全文获取类型
收费全文 | 24620篇 |
免费 | 4953篇 |
国内免费 | 3398篇 |
专业分类
化学 | 18336篇 |
晶体学 | 379篇 |
力学 | 1497篇 |
综合类 | 246篇 |
数学 | 2611篇 |
物理学 | 9902篇 |
出版年
2024年 | 75篇 |
2023年 | 598篇 |
2022年 | 903篇 |
2021年 | 1104篇 |
2020年 | 1270篇 |
2019年 | 1268篇 |
2018年 | 1062篇 |
2017年 | 996篇 |
2016年 | 1319篇 |
2015年 | 1468篇 |
2014年 | 1628篇 |
2013年 | 2004篇 |
2012年 | 2439篇 |
2011年 | 2386篇 |
2010年 | 1606篇 |
2009年 | 1740篇 |
2008年 | 1824篇 |
2007年 | 1511篇 |
2006年 | 1401篇 |
2005年 | 1132篇 |
2004年 | 837篇 |
2003年 | 614篇 |
2002年 | 570篇 |
2001年 | 464篇 |
2000年 | 389篇 |
1999年 | 368篇 |
1998年 | 289篇 |
1997年 | 263篇 |
1996年 | 221篇 |
1995年 | 198篇 |
1994年 | 153篇 |
1993年 | 162篇 |
1992年 | 129篇 |
1991年 | 102篇 |
1990年 | 83篇 |
1989年 | 61篇 |
1988年 | 57篇 |
1987年 | 50篇 |
1986年 | 49篇 |
1985年 | 45篇 |
1984年 | 26篇 |
1983年 | 23篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1977年 | 5篇 |
1975年 | 5篇 |
1971年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Jie Lu Ju-Kang Wu Yao Jiang Dr. Peng Tan Lin Zhang Yu Lei Prof. Xiao-Qin Liu Prof. Lin-Bing Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(16):6490-6496
Hierarchically porous metal–organic frameworks (HP-MOFs) are promising in various applications. Most reported HP-MOFs are prepared based on the generation of mesopores in microporous frameworks, and the formed mesopores are connected by microporous channels, limiting the accessibility of mesopores for bulky molecules. A hierarchical structure is formed by constructing microporous MOFs in uninterrupted mesoporous tunnels. Using the confined space in as-prepared mesoporous silica, highly dispersed metal precursors for MOFs are coated on the internal surface of mesoporous tunnels. Ligand vapor-induced crystallization is employed to enable quantitative formation of MOFs in situ, in which sublimated ligands diffuse into mesoporous tunnels and react with metal precursors. The obtained hierarchically porous composites exhibit record-high adsorption capacity for the bulky molecule trypsin. The thermal and storage stability of trypsin is improved upon immobilization on the composites. 相似文献
12.
13.
14.
15.
In the view of substrate availability, atomic efficiency and cost, directly using arenols as coupling partners in cross‐coupling, would be one of the most attractive goals. Up to date, many efforts have been made to activate the C—O bond of phenols with different strategies, for example, through in‐situ formed intermediates, through a catalytic reductive dearomatization‐condensation‐rearomatization sequence or catalytic deoxygenation. In this review, we summarized recent advances in cross‐couplings of arenols as the electrophiles via C—O activation. 相似文献
16.
17.
Lithium-sulfur batteries (LSBs) with high energy density and low cost have been recognized as one of the most promising next-generation energy storage systems. Although it has taken decades of development, the practical application of LSBs has been hindered by several inherent obstacles, particularly the severe shuttle effect and sluggish reaction kinetics in the sulfur cathode. Various strategies have been proposed to address these problems via rational design of electrode materials and configurations. Freestanding sulfur cathode could be a promising strategy to improve the sulfur mass loading at the cathode level and energy density of LSBs. This minireview will briefly summary the recent advances in freestanding cathodes for LSBs. The advantages and disadvantages of various freestanding cathodes are discussed and the prospects for the development of flexible cathodes are envisioned. 相似文献
18.
Hierarchical motion planning at the acceleration level based on task priority matrix for space robot
Nonlinear Dynamics - A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge is to... 相似文献
19.
Nonlinear Dynamics - Conventional tuned liquid column dampers (TLCDs) are deficient in multidirectionality. In contrast, toroidal TLCDs are designed to extend the application to multidirectional... 相似文献
20.
Chen Fenge Li Bing Peng Xingchun 《Methodology and Computing in Applied Probability》2022,24(2):635-659
Methodology and Computing in Applied Probability - This paper is devoted to the study of an optimal investment and risk control problem for an insurer. The risky asset process and the insurance... 相似文献