全文获取类型
收费全文 | 60663篇 |
免费 | 10650篇 |
国内免费 | 9057篇 |
专业分类
化学 | 30117篇 |
晶体学 | 696篇 |
力学 | 2673篇 |
综合类 | 639篇 |
数学 | 4626篇 |
物理学 | 17128篇 |
无线电 | 24491篇 |
出版年
2024年 | 270篇 |
2023年 | 1294篇 |
2022年 | 2006篇 |
2021年 | 2361篇 |
2020年 | 2229篇 |
2019年 | 2170篇 |
2018年 | 1975篇 |
2017年 | 2253篇 |
2016年 | 2546篇 |
2015年 | 3164篇 |
2014年 | 3782篇 |
2013年 | 4654篇 |
2012年 | 5272篇 |
2011年 | 5291篇 |
2010年 | 4462篇 |
2009年 | 4539篇 |
2008年 | 4779篇 |
2007年 | 4275篇 |
2006年 | 3953篇 |
2005年 | 3167篇 |
2004年 | 2431篇 |
2003年 | 2088篇 |
2002年 | 2111篇 |
2001年 | 1749篇 |
2000年 | 1575篇 |
1999年 | 1118篇 |
1998年 | 732篇 |
1997年 | 610篇 |
1996年 | 575篇 |
1995年 | 468篇 |
1994年 | 464篇 |
1993年 | 354篇 |
1992年 | 301篇 |
1991年 | 225篇 |
1990年 | 212篇 |
1989年 | 141篇 |
1988年 | 128篇 |
1987年 | 114篇 |
1986年 | 106篇 |
1985年 | 71篇 |
1984年 | 47篇 |
1983年 | 45篇 |
1982年 | 34篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 25篇 |
1977年 | 12篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1925年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Hui Zhang Yinkun Sun Junjie Yang Zhiyu Sun Yanxin Zhao Xin Li Wei Wang Dongwei Lu Jun Ma 《Advanced functional materials》2023,33(40):2302816
Precise adjustment of the pore size, damage repair, and efficient cleaning is all challenges for the wider application of inorganic membranes. This study reports a simple strategy of combining dry-wet spinning and electrosynthesis to fabricate stainless-steel metal–organic framework composite membranes characterized by customizable pore sizes, targeted reparability, and high catalytic activity for membrane cleaning. The membrane pore size can be precisely customized in the range of 14–212 nm at nanoscale, and damaged membranes can be repaired by targeted treatment in 120 s. In addition, advanced oxidation processes can be used to quickly clean the membrane and achieve 98% flux recovery. The synergistic actions of the membrane matrix and the selective layer increase the adsorption energy of active sites to oxidant, shorten the electron transfer cycle, and enhance the overall catalytic performance. This study can provide a new direction for the development of advanced membranes for water purification and high-efficiency membrane cleaning methods. 相似文献
102.
Yuntong Guo Zhenyu Chen Jinfeng Ge Jintao Zhu Jinna Zhang Yuanyuan Meng Qinrui Ye Shijie Wang Fei Chen Wei Ma Ziyi Ge 《Advanced functional materials》2023,33(47):2305611
Material design of guest acceptor is always a big challenge for improving the efficiency of ternary organic solar cells (OSCs). Here, a pair of isomeric nonfullerene acceptors based on quinoxaline core, Qx–p-C7H8O and Qx–m-C7H8O, is designed and synthesized. By moving the alkoxy chain attached on side phenyl from meta-position to para-position, both π–π stacking distance and crystallinity are enhanced simultaneously. They obtain the uplifted lowest unoccupied molecular orbital level. Compared to Qx–m-C7H8O, Qx–p-C7H8O exhibits wider absorption spectrum and higher extinction coefficient. Using D18-Cl:N3 as host materials, the addition of guest acceptor Qx–p-C7H8O significantly improves the power conversion efficiency (PCE) from 17.61% to 18.49% because of higher open-circuit voltage (0.875 V) and short-circuit current density (27.85 mA cm−2). This can be attributed to the faster exciton dissociation, more balanced carrier mobility, fine fiber morphology, and lower energy loss in the ternary devices. However, Qx–m-C7H8O-based ternary device achieves relatively low PCE of 17.17% because this device shows extremely low electron mobility. The results indicate that molecular stacking, film morphology, etc., can be effectively modulated by fine-tuning the side chains of guest materials, which may be an effective design rule for further improving the PCE of OSCs. 相似文献
103.
Chunsan Deng Yuncheng Liu Xuhao Fan Binzhang Jiao Zexu Zhang Mingduo Zhang Fayu Chen Hui Gao Leimin Deng Wei Xiong 《Advanced functional materials》2023,33(11):2211473
Intelligent micromachines that respond to external light stimuli have a broad range of potential applications, such as microbots, biomedicine, and adaptive optics. However, artificial light-driven intelligent micromachines with a low actuation threshold, rapid responsiveness, and designable and precise 3D transformation capability remain unachievable to date. Here, a single-material and one-step 4D printing strategy are proposed to enable the nanomanufacturing of agile and low-threshold light-driven 3D micromachines with programmable shape-morphing characteristics. The as-developed carbon nanotube-doped composite hydrogel simultaneously enhanced the light absorption, thermal conductivity, and mechanical modulus of the crosslinked network, thus significantly increasing the light sensitivity and response speed of micromachines. Moreover, the structural design and assembly of asymmetric microscale mechanical metamaterial unit cells enable the highly efficient additive nanomanufacturing of 3D shape-morphable micromachines with large dynamic modulation and spatiotemporal controllability. Using this strategy, the world's smallest artificial beating heart with programmable light-stimulus responsiveness for the cardiac cycle is successfully printed. This 4D printing method paves the way for the construction of multifunctional intelligent micromachines for bionics, drug delivery, integrated microsystems, and other fields. 相似文献
104.
Shi Fang Liuan Li Danhao Wang Wei Chen Yang Kang Weiyi Wang Xin Liu Yuanmin Luo Huabin Yu Haochen Zhang Muhammad Hunain Memon Wei Hu Jr-Hau He Chen Gong Chengjie Zuo Sheng Liu Haiding Sun 《Advanced functional materials》2023,33(37):2214408
Underwater optical communication (UOC) has attracted considerable interest in the continuous expansion of human activities in marine/ocean environments. The water-durable and self-powered photoelectrodes that act as a battery-free light receiver in UOC are particularly crucial, as they may directly face complex underwater conditions. Emerging photoelectrochemical (PEC)-type photodetectors are appealing owing to their intrinsic aqueous operation characteristics with versatile tunability of photoresponses. Herein, a self-powered PEC photodetector employing n-type gallium nitride (GaN) nanowires as a photoelectrode, which is decorated with an iridium oxide (IrOx) layer to optimize charge transfer dynamics at the GaN/electrolyte interface, is reported. Strikingly, the constructed n-GaN/IrOx photoelectrode breaks the responsivity-bandwidth trade-off limit by simultaneously improving the response speed and responsivity, delivering an ultrafast response speed with response/recovery times of only 2 µs/4 µs while achieving a high responsivity of 110.1 mA W−1. Importantly, the device exhibits a large bandwidth with 3 dB cutoff frequency exceeding 100 kHz in UOC tests, which is one of the highest values among self-powered photodetectors employed in optical communication system. 相似文献
105.
Fenglei Lyu Bingyun Ma Xulan Xie Daqi Song Yuebin Lian Hao Yang Wei Hua Hao Sun Jun Zhong Zhao Deng Tao Cheng Yang Peng 《Advanced functional materials》2023,33(26):2214609
Cobalt phthalocyanine (CoPc) anchored on heterogeneous scaffold has drawn great attention as promising electrocatalyst for carbon dioxide reduction reaction (CO2RR), but the molecule/substrate interaction is still pending for clarification and optimization to maximize the reaction kinetics. Herein, a CO2RR catalyst is fabricated by affixing CoPc onto the Mg(OH)2 substrate primed with conductive carbon, demonstrating an ultra-low overpotential of 0.31 ± 0.03 V at 100 mA cm−2 and high faradaic efficiency of >95% at a wide current density range for CO production, as well as a heavy-duty operation at 100 mA cm−2 for more than 50 h in a membrane electrode assembly. Mechanistic investigations employing in situ Raman and attenuated total reflection surface-enhanced infrared absorption spectroscopy unravel that Mg(OH)2 plays a pivotal role to enhance the CO2RR kinetics by facilitating the first-step electron transfer to form anionic *CO2− intermediates. DFT calculations further elucidate that introducing Lewis acid sites help to polarize CO2 molecules absorbed at the metal centers of CoPc and consequently lower the activation barrier. This work signifies the tailoring of catalyst-support interface at molecular level for enhancing the turnover rate of CO2RR. 相似文献
106.
Yingjie Kong Wenjian Shen Haoyu Cai Wei Dong Cong Bai Juan Zhao Fuzhi Huang Yi-Bing Cheng Jie Zhong 《Advanced functional materials》2023,33(25):2300932
Despite the rapid developments are achieved for perovskite solar cells (PSCs), the existence of various defects in the devices still limits the further enhancement of the power conversion efficiency (PCE) and the long-term stability of devices. Herein, the efficient organic potassium salt (OPS) of para-halogenated phenyl trifluoroborates is presented as the precursor additives to improve the performance of PSCs. Studies have shown that the 4-chlorophenyltrifluoroborate potassium salt (4-ClPTFBK) exhibits the most effective interaction with the perovskite lattice. Strong coordination between BF3−/halogen in anion and uncoordinated Pb2+/halide vacancies, along with the hydrogen bond between F in BF3− and H in FA+ are observed. Thus, due to the synergistic contribution of the potassium and anionic groups, the high-quality perovskite film with large grain size and low defect density is achieved. As a result, the optimal devices show an enhanced efficiency of 24.50%, much higher than that of the control device (22.63%). Furthermore, the unencapsulated devices present remarkable thermal and long-term stability, maintaining 86% of the initial PCE after thermal test at 80 °C for 1000 h and 95% after storage in the air for 2460 h. 相似文献
107.
Ruiqi Li Lian Chen Qin Ji Qing Liang Ying Zhu Wei Fu Tianyou Chen Hongwei Duan Wenshan He Zushun Xu Xiaofang Dai Jinghua Ren 《Advanced functional materials》2023,33(37):2213292
Radiotherapy is identified as a crucial treatment for patients with glioblastoma, but recurrence is inevitable. The efficacy of radiotherapy is severely hampered partially due to the tumor evolution. Growing evidence suggests that proneural glioma stem cells can acquire mesenchymal features coupled with increased radioresistance. Thus, a better understanding of mechanisms underlying tumor subclonal evolution may develop new strategies. Herein, data highlighting a positive correlation between the accumulation of macrophage in the glioblastoma microenvironment after irradiation and mesenchymal transdifferentiation in glioblastoma are presented. Mechanistically, elevated production of inflammatory cytokines released by macrophages promotes mesenchymal transition in an NF-κB-dependent manner. Hence, rationally designed macrophage membrane-coated porous mesoporous silica nanoparticles (MMNs) in which therapeutic anti-NF-κB peptides are loaded for enhancing radiotherapy of glioblastoma are constructed. The combination of MMNs and fractionated irradiation results in the blockage of tumor evolution and therapy resistance in glioblastoma-bearing mice. Intriguingly, the macrophage invasion across the blood-brain barrier is inhibited competitively by MMNs, suggesting that these nanoparticles can fundamentally halt the evolution of radioresistant clones. Taken together, the biomimetic MMNs represent a promising strategy that prevents mesenchymal transition and improves therapeutic response to irradiation as well as overall survival in patients with glioblastoma. 相似文献
108.
Haiping Wu Shun Huang Ying Zhu Jia Li Xiaoxiao Pang Yongyao Tang Siqiao Li Ping Ji Shijia Ding Wei Cheng Wenyang Li 《Advanced functional materials》2023,33(19):2212669
The accumulation of reactive oxygen species (ROS) and minimal osteogenic raw material in the osteoporotic bone microenvironment greatly inhibits the activity of osteoblasts. Herein, it is originally proposed to construct a biomatrix multifaceted bone microenvironment amendment -Mineralized zippered G4-Hemin DNAzyme hydrogel (MDH)-to improve osteoporotic osteogenic capacity and promote high-quality bone defect repair. The programmed design of the rolling circle amplified DNA hydrogel synthesis system allows the introduction of massive amounts of zippered G4-Hemin DNAzyme in MDH. The zippered G4-Hemin DNAzyme highly mimics the tight catalytic configuration of horseradish peroxidase and exerts excellent enzyme-like activity with considerable ROS molecule scavenging ability. In addition, the DNA amplification by-product pyrophosphate is ingeniously employed as a sufficient phosphorus source, thus constituting an autonomous mineralization system for waste reuse through the introduction of pyrophosphate hydrolase and calcium ions, which deposits in MDH as an osteogenic raw material and addresses the challenge of DNA hydrogel bio-application stability. The remarkable in vitro and in vivo outcomes demonstrate that MDH can effectively improve the oxidative stress status of osteoblasts, restore the balance of mitochondrial membrane potential, and reduce apoptosis, ultimately demonstrating superior osteogenic capacity. 相似文献
109.
Xinzhen Lu Yifeng Cheng Menghao Li Yucheng Zou Cheng Zhen Duojie Wu Xianbin Wei Xiangyan Li Xuming Yang Meng Gu 《Advanced functional materials》2023,33(12):2212847
Solid-state lithium metal batteries (SSLMBs) are a promising candidate for next-generation energy storage systems due to their intrinsic safety and high energy density. However, they still suffer from poor interfacial stability, which can incur high interfacial resistance and insufficient cycle lifespan. Herein, a novel poly(vinylidene fluoride‑hexafuoropropylene)-based polymer electrolyte (PPE) with LiBF4 and propylene carbonate plasticizer is developed, which has a high room-temperature ionic conductivity up to 1.15 × 10−3 S cm−1 and excellent interfacial stability. Benefitting from the stable interphase, the PPE-based symmetric cell can operate for over 1000 h. By virtue of cryogenic transmission electron microscopy (Cryo-TEM) characterization, the high interfacial compatibility between Li metal anode and PPE is revealed. The solid electrolyte interphase is made up of an amorphous outer layer that can keep intimate contact with PPE and an inner Li2O-dominated layer that can protect Li from continuous side reactions during battery cycling. A LiF-rich transition layer is also discovered in the region of PPE close to Li metal anode. The feasibility of investigating interphases in polymer-based solid-state batteries via Cryo-TEM techniques is demonstrated, which can be widely employed in future to rationalize the correlation between solid-state electrolytes and battery performance from ultrafine interfacial structures. 相似文献
110.
本文介绍了一种基于砷化镓材料的高功率490~530 GHz单片集成三倍频器。基于提出的对称平衡结构,该三倍频器不仅可以实现良好的振幅和相位平衡,用来实现高效的功率合成,还可以在没有任何旁路电容的情况下提供直流偏置路径以保证高效倍频效率。同时,开展容差性仿真分析二极管关键电气参数与结构参数对倍频性能的影响研究,以便最大化提升倍频性能。最终,在大约80~200 mW的输入功率驱动下,研制的510 GHz三倍频,在490~530 GHz频率范围内,输出功率为4~16 mW,其中峰值倍频效率11%。在522 GHz频点处,该三倍频在218 mW的输入功率驱动下,产生16 mW的最大输出功率。该三倍频器后期将用于1 THz的固态外超外差混频器的本振源。 相似文献