全文获取类型
收费全文 | 93311篇 |
免费 | 18736篇 |
国内免费 | 9779篇 |
专业分类
化学 | 81191篇 |
晶体学 | 1180篇 |
力学 | 4150篇 |
综合类 | 620篇 |
数学 | 9155篇 |
物理学 | 25530篇 |
出版年
2024年 | 177篇 |
2023年 | 1066篇 |
2022年 | 2031篇 |
2021年 | 2260篇 |
2020年 | 3281篇 |
2019年 | 4536篇 |
2018年 | 2908篇 |
2017年 | 2650篇 |
2016年 | 5781篇 |
2015年 | 6104篇 |
2014年 | 6618篇 |
2013年 | 8294篇 |
2012年 | 8094篇 |
2011年 | 7683篇 |
2010年 | 6698篇 |
2009年 | 6723篇 |
2008年 | 6669篇 |
2007年 | 5514篇 |
2006年 | 4902篇 |
2005年 | 4486篇 |
2004年 | 3625篇 |
2003年 | 3096篇 |
2002年 | 3755篇 |
2001年 | 2826篇 |
2000年 | 2507篇 |
1999年 | 1497篇 |
1998年 | 971篇 |
1997年 | 861篇 |
1996年 | 830篇 |
1995年 | 677篇 |
1994年 | 663篇 |
1993年 | 571篇 |
1992年 | 513篇 |
1991年 | 425篇 |
1990年 | 372篇 |
1989年 | 285篇 |
1988年 | 250篇 |
1987年 | 199篇 |
1986年 | 213篇 |
1985年 | 205篇 |
1984年 | 133篇 |
1983年 | 102篇 |
1982年 | 92篇 |
1981年 | 69篇 |
1980年 | 62篇 |
1979年 | 78篇 |
1978年 | 49篇 |
1976年 | 47篇 |
1974年 | 49篇 |
1973年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns... 相似文献
2.
Lin Yu Wu Yeyu Tan Xuecai Wu Jiawen Huang Kejing Mi Yan Ou Panpan Wei Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin... 相似文献
3.
Mathematical Programming - We provide a control-theoretic perspective on optimal tensor algorithms for minimizing a convex function in a finite-dimensional Euclidean space. Given a function... 相似文献
4.
Shilin Jiang Dr. Yalan Liu Dr. Lin Wang Prof. Zhifang Chai Prof. Wei-Qun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201145
The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties. 相似文献
5.
6.
Zhengcheng Wang Shangyan Zhou Wei Liao Qian Zhou Meida Chen Jin Long Prof. Qingmei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202201987
The designs of efficient and inexpensive Pt-based catalysts for methanol oxidation reaction (MOR) are essential to boost the commercialization of direct methanol fuel cells. Here, the highly catalytic performance PtFe alloys supported on multiwalled carbon nanotubes (MWCNTs) decorating nitrogen-doped carbon (NC) have been successfully prepared via co-engineering of the surface composition and electronic structure. The Pt1Fe3@NC/MWCNTs catalyst with moderate Fe3+ feeding content (0.86 mA/mgPt) exhibits 2.26-fold enhancement in MOR mass activity compared to pristine Pt/C catalyst (0.38 mA/mgPt). Furthermore, the CO oxidation initial potential of Pt1Fe3@NC/MWCNTs catalyst is lower relative to Pt/C catalyst (0.71 V and 0.80 V). Benefited from the optimal surface compositions, the anti-corrosion ability of MWCNT, strong electron interaction between PtFe alloys and MWCNTs and the N-doped carbon (NC) layer, the Pt1Fe3@NC/MWCNTs catalyst presents an improved MOR performance and anti-CO poisoning ability. This study would open up new perspective for designing efficient electrocatalysts for the DMFCs field. 相似文献
7.
8.
9.
Li Jun Zheng Dayong Wei Ning Sun Yunfeng Liu Li Yuan Yuan Jiang Qinghua 《Chemistry of Natural Compounds》2022,58(4):650-652
Chemistry of Natural Compounds - A new quassinoid, dehydrobruceantinol B (1), was isolated from the seeds of Brucea javanica, together with two known compounds, bruceantinol (2) and bruceine A (3).... 相似文献
10.
Wei Yuting Wang Qihua Liu Wei 《Annals of the Institute of Statistical Mathematics》2021,73(3):535-553
Annals of the Institute of Statistical Mathematics - In this paper, a model averaging approach is developed for the linear regression models with response missing at random. It is shown that the... 相似文献