全文获取类型
收费全文 | 4119篇 |
免费 | 697篇 |
国内免费 | 350篇 |
专业分类
化学 | 2714篇 |
晶体学 | 55篇 |
力学 | 300篇 |
综合类 | 19篇 |
数学 | 401篇 |
物理学 | 1677篇 |
出版年
2024年 | 18篇 |
2023年 | 116篇 |
2022年 | 161篇 |
2021年 | 184篇 |
2020年 | 169篇 |
2019年 | 164篇 |
2018年 | 162篇 |
2017年 | 129篇 |
2016年 | 223篇 |
2015年 | 201篇 |
2014年 | 237篇 |
2013年 | 312篇 |
2012年 | 384篇 |
2011年 | 372篇 |
2010年 | 250篇 |
2009年 | 217篇 |
2008年 | 241篇 |
2007年 | 225篇 |
2006年 | 216篇 |
2005年 | 178篇 |
2004年 | 131篇 |
2003年 | 104篇 |
2002年 | 83篇 |
2001年 | 76篇 |
2000年 | 84篇 |
1999年 | 73篇 |
1998年 | 69篇 |
1997年 | 52篇 |
1996年 | 59篇 |
1995年 | 53篇 |
1994年 | 29篇 |
1993年 | 42篇 |
1992年 | 41篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 1篇 |
1983年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有5166条查询结果,搜索用时 15 毫秒
101.
Dou Ma Ping Li Xiangyu Duan Jiazhen Li Pengpeng Shao Zhongling Lang Lixia Bao Yuanyuan Zhang Zhengguo Lin Bo Wang 《Angewandte Chemie (International ed. in English)》2020,59(10):3905-3909
Metal–organic frameworks (MOFs) with long‐term stability and reversible high water uptake properties can be ideal candidates for water harvesting and indoor humidity control. Now, a mesoporous and highly stable MOF, BIT‐66 is presented that has indoor humidity control capability and a photocatalytic bacteriostatic effect. BIT‐66 (V3(O)3(H2O)(BTB)2), possesses prominent moisture tunability in the range of 45–60 % RH and a water uptake and working capacity of 71 and 55 wt %, respectively, showing good recyclability and excellent performance in water adsorption–desorption cycles. Importantly, this MOF demonstrates a unique photocatalytic bacteriostatic behavior under visible light, which can effectively ameliorate the bacteria and/or mold breeding problem in water adsorbing materials. 相似文献
102.
Hui Duan Wan‐Ping Chen Min Fan Wen‐Peng Wang Le Yu Shuang‐Jie Tan Xiang Chen Qiang Zhang Sen Xin Li‐Jun Wan Yu‐Guo Guo 《Angewandte Chemie (International ed. in English)》2020,59(29):12069-12075
Garnet‐type electrolytes suffer from unstable chemistry against air exposure, which generates contaminants on electrolyte surface and accounts for poor interfacial contact with the Li metal. Thermal treatment of the garnet at >700 °C could remove the surface contaminants, yet it regenerates the contaminants in the air, and aggravates the Li dendrite issue as more electron‐conducting defective sites are exposed. In a departure from the removal approach, here we report a new surface chemistry that converts the contaminants into a fluorinated interface at moderate temperature <180 °C. The modified interface shows a high electron tunneling barrier and a low energy barrier for Li+ surface diffusion, so that it enables dendrite‐proof Li plating/stripping at a high critical current density of 1.4 mA cm?2. Moreover, the modified interface exhibits high chemical and electrochemical stability against air exposure, which prevents regeneration of contaminants and keeps high critical current density of 1.1 mA cm?2. The new chemistry presents a practical solution for realization of high‐energy solid‐state Li metal batteries. 相似文献
103.
Kaikai Wen Lifen Wu Xiaoxi Wu Ying Lu Tao Duan Han Ma Aidong Peng Qinqin Shi Hui Huang 《Angewandte Chemie (International ed. in English)》2020,59(31):12756-12761
Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano‐agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy‐Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3. The photothermal and photodynamic effects of semiconducting nano‐agents under the first near‐infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy‐Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano‐agents for cancer treatment. 相似文献
104.
Qiang-Ming Li Hui Jiang Xue-Qiang Zha Li-Hua Pan Jun Duan 《Natural product research》2020,34(4):563-566
AbstractThe stems of Dendrobium huoshanense have long been used to prevent various diseases, including inflammatory diseases. This study was aimed to explain the anti-inflammatory effect of D. huoshanense stems in LPS-induced RAW 264.7 macrophages and to discover potential anti-inflammatory compounds. Results exhibited that D. huoshanense stems ethanol extract could significantly inhibit LPS-induced production of NO, TNF-α and IL-1β. Based on bioassay guided strategy, four bibenzyls (1–4) were isolated from D. huoshanense stems for the first time. Anti-inflammatory assay showed 1–4 could remarkably inhibit the production of NO in LPS-induced macrophages. Moreover, quantitative RT-PCR analysis displayed that the mRNA levels of iNOs, TNF-α and IL-1β could also be significantly reduced by 1–4. These results suggested that D. huoshanense stems ethanol extract and bibenzyls 1–4 might be well developed as therapeutic agent to prevent inflammatory diseases. 相似文献
105.
We conduct extensive research into the structures of BexZn1-xOO ternary alloys in a pressure range of 0-60GPa,using the ab initio total energy evolutionary algorithm and total energy calculations,finding several metastable structures.Our pressure-composition phase diagram is constructed using the enthalpy results.In addition,we calculate the electronic structures of the BexZn1-xOO structures and investigate the bandgap values at varying pressures and Be content.The calculated results show that the bandgap of the BexZn1-xOO ternary alloys increases with an increase in Be content at the same pressure.Moreover,the bandgap of the BexZn1-xOO ternary alloys increases with the increasing pressure with fixed Be content.At the same Be content,the formation enthalpy of the BexZn1-xOO ternary alloys first decreases,then increases with the increasing pressure. 相似文献
106.
107.
108.
颗粒材料三维应力路径下的接触组构特性 总被引:1,自引:0,他引:1
颗粒材料的宏观应力变形特征与其微观接触力、组构等紧密相关.一般而言,强接触系统属于颗粒内部体系的传力结构,其对应的组构张量是影响宏观应力性质的重要因素.细观数值方法(如离散单元法)能够反映物理试验的基本规律,并且可以方便地提取宏微观数据来研究颗粒体系的应力变形机制.采用离散单元法(discrete element method,DEM)进行一系列等$p$等$b$应力路径下颗粒材料的真三轴试验,在此基础上研究了三维应力路径下颗粒材料的宏微观力学参数的演化过程、三维组构张量与应力张量多重联系以及强接触体系反映的宏观应力特征.研究表明:颗粒体系偏应力峰值状态和临界状态均存在与加载路径无关的宏微观特征;三维应力路径下组构张量与应力张量存在非共轴性,但其联合不变量演化过程表现出加载路径无关的特征;与弱接触系统的组构张量相比,强接触系统的组构张量更能反映宏观应力张量的特征;强弱接触体系的组构张量对颗粒体系宏观响应的贡献不同,其分界点存在一定取值范围,但采用平均接触力较为简单合理. 相似文献
109.
Li-Wei Wang Songwei Jiang Ying-Hui Yuan Jilong Duan Nian-Dong Mao Zi Hui Renren Bai Tian Xie Xiang-Yang Ye 《Molecules (Basel, Switzerland)》2022,27(8)
As one of the key phosphatidylinositol 3-kinase-related kinases (PIKKs) family members, ataxia telangiectasia and RAD3-related protein kinase (ATR) is crucial in maintaining mammalian cell genomic integrity in DNA damage response (DDR) and repair pathways. Dysregulation of ATR has been found across different cancer types. In recent years, the inhibition of ATR has been proven to be effective in cancer therapy in preclinical and clinical studies. Importantly, tumor-specific alterations such as ATM loss and Cyclin E1 (CCNE1) amplification are more sensitive to ATR inhibition and are being exploited in synthetic lethality (SL) strategy. Besides SL, synergistic anticancer effects involving ATRi have been reported in an increasing number in recent years. This review focuses on the recent advances in different forms of synergistic antitumor effects, summarizes the pharmacological benefits and ongoing clinical trials behind the biological mechanism, and provides perspectives for future challenges and opportunities. The hope is to draw awareness to the community that targeting ATR should have great potential in developing effective anticancer medicines. 相似文献
110.
The development of display technology has continuously increased the requirements for image resolution. However, the imaging systems of many cameras are limited by their physical conditions, and the image resolution is often restrictive. Recently, several models based on deep convolutional neural network (CNN) have gained significant performance for image super-resolution (SR), while extensive memory consumption and computation overhead hinder practical applications. For this purpose, we present a lightweight network that automatically searches dense connection (ASDCN) for image super-resolution (SR), which effectively reduces redundancy in dense connection and focuses on more valuable features. We employ neural architecture search (NAS) to model the searching of dense connections. Qualitative and quantitative experiments on five public datasets show that our derived model achieves superior performance over the state-of-the-art models. 相似文献