全文获取类型
收费全文 | 87525篇 |
免费 | 13152篇 |
国内免费 | 9058篇 |
专业分类
化学 | 59816篇 |
晶体学 | 1001篇 |
力学 | 5012篇 |
综合类 | 511篇 |
数学 | 10323篇 |
物理学 | 33072篇 |
出版年
2025年 | 34篇 |
2024年 | 914篇 |
2023年 | 1888篇 |
2022年 | 3285篇 |
2021年 | 3686篇 |
2020年 | 4106篇 |
2019年 | 3871篇 |
2018年 | 2998篇 |
2017年 | 2703篇 |
2016年 | 4123篇 |
2015年 | 3988篇 |
2014年 | 4927篇 |
2013年 | 6224篇 |
2012年 | 7388篇 |
2011年 | 7593篇 |
2010年 | 5274篇 |
2009年 | 5030篇 |
2008年 | 5385篇 |
2007年 | 4750篇 |
2006年 | 4478篇 |
2005年 | 3797篇 |
2004年 | 2999篇 |
2003年 | 2331篇 |
2002年 | 2152篇 |
2001年 | 1770篇 |
2000年 | 1544篇 |
1999年 | 1620篇 |
1998年 | 1365篇 |
1997年 | 1260篇 |
1996年 | 1264篇 |
1995年 | 1130篇 |
1994年 | 1004篇 |
1993年 | 799篇 |
1992年 | 724篇 |
1991年 | 626篇 |
1990年 | 549篇 |
1989年 | 407篇 |
1988年 | 317篇 |
1987年 | 258篇 |
1986年 | 273篇 |
1985年 | 219篇 |
1984年 | 151篇 |
1983年 | 124篇 |
1982年 | 106篇 |
1981年 | 66篇 |
1980年 | 50篇 |
1979年 | 21篇 |
1978年 | 19篇 |
1976年 | 18篇 |
1957年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
Xin-Zhang Yu Wen-Long Wei Yu-Lan Niu Xing Li Ming Wang Wen-Chao Gao 《Molecules (Basel, Switzerland)》2022,27(19)
Symmetrical diaryl sulfides and diaryl disulfides have been efficiently and selectively constructed via the homocoupling of sodium arenesulfinates. The selectivity of products relied on the different reaction systems: symmetrical diaryl sulfides were predominately obtained under the Pd(OAc)2 catalysis, whereas symmetrical diaryl sulfides were exclusively yielded in the presence of the reductive Fe/HCl system. 相似文献
202.
Lingyun Lou Tianqi Xu Yuzhan Li Changli Zhang Bochun Wang Xusheng Zhang Hean Zhang Yuting Qiu Junyan Yang Dong Wang Hui Cao Wanli He Zhou Yang 《Molecules (Basel, Switzerland)》2022,27(19)
Pure organic room-temperature phosphorescence (RTP) materials built upon noncovalent interactions have attracted much attention because of their high efficiency, long lifetime, and stimulus-responsive behavior. However, there are limited reports of noncovalent RTP materials because of the lack of specific design principles and clear mechanisms. Here, we report on a noncovalent material prepared via facile grinding that can emit fluorescence and RTP emission differing from their components’ photoluminescent behavior. Exciplex can be formed during the preparation process to act as the minimum emission unit. We found that H-bonds in the RTP system provide restriction to nonradiative transition but also enhance energy transformation and energy level degeneracy in the system. Moreover, water-stimulated photoluminescent ink is produced from the materials to achieve double-encryption application with good resolution. 相似文献
203.
Weiwen Zheng Zuhao Li Kaijin Chen Siwei Liu Zhenguo Chi Jiarui Xu Yi Zhang 《Molecules (Basel, Switzerland)》2022,27(19)
High dielectric constant polymers have been widely studied and concerned in modern industry, and the induction of polar groups has been confirmed to be effective for high permittivity. However, the way of connection of polar groups with the polymer backbone and the mechanism of their effect on the dielectric properties are unclear and rarely reported. In this study, three polyimides (C0-SPI, C1-SPI, and C2-SPI) with the same rigid backbone and different linking groups to the dipoles were designed and synthesized. With their rigid structure, all of the polyimides show excellent thermal stability. With the increase in the flexibility of linking groups, the dielectric constant of C0-SPI, C1-SPI, and C2-SPI enhanced in turn, showing values of 5.6, 6.0, and 6.5 at 100 Hz, respectively. Further studies have shown that the flexibility of polar groups affected the dipole polarization, which was positively related to the dielectric constant. Based on their high permittivity and high temperature resistance, the polyimides exhibited outstanding energy storage capacity even at 200 °C. This discovery reveals the behavior of the dipoles in polymers, providing an effective strategy for the design of high dielectric constant materials. 相似文献
204.
Guangxu Xing Xuefeng Sun Ning Li Xuewu Li Tiantian Wu Fangyu Wang 《Molecules (Basel, Switzerland)》2022,27(19)
With the continuous development of China’s economy and society, people and the government have higher and higher requirements for food safety. Testing for food dopants and toxins can prevent the occurrence of various adverse health phenomena in the world’s population. By deploying new and powerful sensors that enable rapid sensing processes, the food industry can help detect trace adulteration and toxic substances. At present, as a common food safety detection method, lateral flow immunochromatography (LFI) is widely used in food safety testing, environmental testing and clinical medical treatment because of its advantages of simplicity, speed, specificity and low cost, and plays a pivotal role in ensuring food safety. This paper mainly focuses on the application of lateral flow immunochromatography and new technologies combined with test strips in food safety detection, such as aptamers, surface-enhanced Raman spectroscopy, quantum dots, electrochemical test strip detection technology, biosensor test strip detection, etc. In addition, sensing principles such as fluorescence resonance energy transfer can also more effective. Different methods have different characteristics. The following is a review of the application of these technologies in food safety detection. 相似文献
205.
Herein, a 3D hierarchical structure is constructed by growing NiCo2O4 nanowires on few-layer Ti3C2 nanosheets using Ni foam (NF) as substrate via simple vacuum filtration and solvothermal treatment. Ti3C2 nanosheets are directly anchored on NF surface without binders or surfactants, and NiCo2O4 nanowires composed of about 15 nm nanoparticles uniformly grow on Ti3C2/NF skeleton, which can provide abundant active sites and ion diffusion pathways for enhancing electrochemical performance. Benefiting from the unique structure feature and the synergistic effects of active materials, NiCo2O4/Ti3C2 exhibits a high specific capacitance of 2468 F g−1 at a current density of 0.5 A g−1 and a good rate performance. Based on this, an asymmetric supercapacitor (ASC) based on NiCo2O4/Ti3C2 as positive electrode and activated carbon (AC)/NF as negative electrode is assembled. The ASC achieves a high specific capacitance of 253 F g−1 at 1 A g−1 along with 91.5% retention over 10,000 cycles at 15 A g−1. Furthermore, the ACS presents an outstanding energy density of 90 Wh kg−1 at the power density of 2880 W kg−1. This work provides promising guidance for the fabrication of binder-free, free-standing and hierarchical composites for energy storage application. 相似文献
206.
We report a novel strategy for the front passivation of solar cells via aluminum-doped zinc oxide (AZO) films in the case of CIGS solar cells, leading to the highest efficiency of 15.07% without alkali metal post treatment and anti−reflective layer. The good passivation of CIGS solar cells via AZO films is attributed to the field passivation simulated by the SCAPS−1D software. The AZO films also exhibit high optical transparency both in visible and near infrared wavelength region, high conductivity, and cost−effective fabrication advantage. Importantly, the AZO films are deposited at room temperature via radio−frequency magnetron sputtering, showing that the AZO films are also applicable to other solar cells such as perovskite solar cells. Our work is of significance for advancing the development of CIGS−based photovoltaics devices by the well front passivation of AZO. The wide application of AZO in other solar cells such as perovskite solar cells and related tandem solar cells may also accelerate the development of these solar cells because of potential passivation of AZO, low deposition temperature, and high optical transparency of AZO. 相似文献
207.
Libo He Yang Liu Junling Xu Jingjing Li Guohua Cheng Jiaxiu Cai Jinye Dang Meng Yu Weiyan Wang Wei Duan Ke Liu 《Molecules (Basel, Switzerland)》2022,27(20)
Advanced glycation end products (AGEs) are the compounds produced by non-enzymatic glycation of proteins, which are involved in diabetic-related complications. To investigate the potential anti-glycation activity of Myriocin (Myr), a fungal metabolite of Cordyceps, the effect of Myr on the formation of AGEs resulted from the glycation of bovine serum albumin (BSA) and the interaction between Myr and BSA were studied by multiple spectroscopic techniques and computational simulations. We found that Myr inhibited the formation of AGEs at the end stage of glycation reaction and exhibited strong anti-fibrillation activity. Spectroscopic analysis revealed that Myr quenched the fluorescence of BSA in a static process, with the possible formation of a complex (approximate molar ratio of 1:1). The binding between BSA and Myr mainly depended on van der Waals interaction, hydrophobic interactions and hydrogen bond. The synchronous fluorescence and UV-visible (UV-vis) spectra results indicated that the conformation of BSA altered in the presence of Myr. The fluorescent probe displacement experiments and molecular docking suggested that Myr primarily bound to binding site 1 (subdomain IIA) of BSA. These findings demonstrate that Myr is a potential anti-glycation agent and provide a theoretical basis for the further functional research of Myr in the prevention and treatment of AGEs-related diseases. 相似文献
208.
Supplementation of SDF1 during Pig Oocyte In Vitro Maturation Improves Subsequent Embryo Development
209.
Shuai Yuan Pei-Yu Dong Hao-Hai Ma Sheng-Lin Liang Long Li Xi-Feng Zhang 《Molecules (Basel, Switzerland)》2022,27(20)
In this study, the synthesis parameters of the lotus root polysaccharide iron complex (LRPF) were determined and optimized by response surface methodology. Under the optimum preparation conditions, the pH of the solution was 9, the ratio of M (trisodium citrate): m (lotus root polysaccharide) was 0.45, the reaction time was 3 h. UV spectroscopy, thermogravimetry, FT-IR spectroscopy, X-ray diffraction, CD, and NMR were used for the characterization of the LRPF. LRPF has good stability and easily releases iron ions under artificial gastrointestinal conditions. LRPF exhibited antioxidant activity in vitro and can significantly improve the antioxidant activity in vivo. In addition, LRPF has a good effect in the treatment of iron deficiency anemia in model mice, impacts the gut microbiome, and reduces the iron deficiency-induced perniciousness by regulating steroid hormone biosynthesis. Therefore, LRPF can be used as a nutritional supplement to treat and prevent iron-deficiency anemia and improve human immunity. 相似文献
210.
Yong Hou Meiying Chen Zhaocui Sun Guoxu Ma Deli Chen Haifeng Wu Junshan Yang Yihang Li Xudong Xu 《Molecules (Basel, Switzerland)》2022,27(20)
Indole diterpenes are a large class of secondary metabolites produced by fungi, possessing a cyclic diterpenoid backbone and an indole moiety. Novel structures and important biological activity have made indole diterpenes one of the focuses of synthetic chemists. Although the discovery, identification, structural diversity, biological activity and especially structure–activity relationship of indole diterpenes have been reported in some papers in recent years, they are absent of a systematic and comprehensive analysis, and there is no elucidation of enzymes related to this kind of natural product. Therefore, it is necessary to summarize the relevant reports to provide new perspectives for the following research. In this review, for the first time, the function of related synthases and the structure–activity relationship of indole diterpenes are expounded, and the recent research advances of them are emphasized. 相似文献