全文获取类型
收费全文 | 3131篇 |
免费 | 144篇 |
国内免费 | 9篇 |
专业分类
化学 | 2437篇 |
晶体学 | 27篇 |
力学 | 39篇 |
数学 | 129篇 |
物理学 | 652篇 |
出版年
2023年 | 21篇 |
2022年 | 10篇 |
2021年 | 46篇 |
2020年 | 54篇 |
2019年 | 59篇 |
2018年 | 38篇 |
2017年 | 35篇 |
2016年 | 77篇 |
2015年 | 89篇 |
2014年 | 103篇 |
2013年 | 181篇 |
2012年 | 187篇 |
2011年 | 220篇 |
2010年 | 128篇 |
2009年 | 108篇 |
2008年 | 207篇 |
2007年 | 165篇 |
2006年 | 189篇 |
2005年 | 165篇 |
2004年 | 160篇 |
2003年 | 118篇 |
2002年 | 130篇 |
2001年 | 56篇 |
2000年 | 65篇 |
1999年 | 59篇 |
1998年 | 27篇 |
1997年 | 42篇 |
1996年 | 38篇 |
1995年 | 31篇 |
1994年 | 37篇 |
1993年 | 32篇 |
1992年 | 39篇 |
1991年 | 24篇 |
1990年 | 15篇 |
1989年 | 24篇 |
1988年 | 22篇 |
1987年 | 25篇 |
1986年 | 16篇 |
1985年 | 25篇 |
1984年 | 22篇 |
1983年 | 16篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 20篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1974年 | 13篇 |
1973年 | 13篇 |
排序方式: 共有3284条查询结果,搜索用时 187 毫秒
21.
We define nontempered (exponential growth) function spaces on the Lie group ax+b which are stable under some left-invariant (convergent) star product. The techniques used to achieved the latter come from symmetric spaces geometry and star representation theory. 相似文献
22.
In connection with a characteristic feature of the effective optical potential in the Dirac approach two types of time delays are considered in the relativistic eikonal approximation. One is obtained from the scattering amplitude and the other given by the wave packet motion in the interaction region. These time delays turn out to differ in sign at intermediate energies, in contrast to the agreement between corresponding nonrelativistic time delays. 相似文献
23.
24.
Cyclic voltammetry of TEMPO in aqueous 0.1 M NaOH in the presence of glutathione (GSH) or cysteine (Cys) indicated the following points: (i) Both of the thiols rapidly formed adducts 3 with oxoammonium ion 1 anodically generated from TEMPO. (ii) 3 generated from GSH entered a succeeding reaction that generated N-oxide anion 2- (the reduced TEMPO). (iii) 3 produced from Cys remained intact over the time scale of voltammetry. A structural feature of GSH was considered to contribute to the observed behavior of this tripeptide. Possible structural features were evaluated by screening various thiols on the basis of whether they provided GSH-like voltammetric results. The 3-mercaptopropionamide group with an amide hydrogen in GSH was determined to be responsible for the observed difference between GSH and Cys. The likely function is to transform 3 from GSH into a 5-imino-1,2-oxathiolane intermediate, thereby releasing 2-. Product analysis for reactions of model thiols representing GSH and Cys with 1 provided support for this argument and suggested that the reaction of GSH or Cys with 1 would produce the corresponding disulfides, regardless of whether a five-membered ring intermediate was formed. The proposed function of the 3-mercaptopropionamide moiety of GSH may provide useful insight for the molecular design of exogenous thiol compounds as novel drugs for the treatment of GSH-depletion-related disorders. 相似文献
25.
Dedicated to Professor John C. Sheehan on the occasion of his sixty-fifth birthday. Chemical and biological modifications of bleomycin, an antitumor glycopeptide antibiotic, have been achieved by three procedures analogous to the modifications of penicillin. 相似文献
26.
27.
Chowdhury Wasimul Q. Idehara Kenji Maeda Isamu Umeda Fusako Yagi Kiyohito Miura Yoshiharu Mizoguchi Tadashi 《Applied biochemistry and biotechnology》1996,57(1):361-366
Applied Biochemistry and Biotechnology - A marine photosynthetic bacterium,Rhodopseudomonas sp. strain W-1S, accumulated polyhydroxybutyrate (PHB) to 56% of the dry cell weight under microaerobic... 相似文献
28.
29.
30.
Tae Oan Ahn Jung Ho Kim Jong Chan Lee Han Mo Jeong Jong-Yoon Park 《Journal of polymer science. Part A, Polymer chemistry》1993,31(2):435-441
A macro-azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy-terminated polyarylates having viscosity-average molecular weights of 6200, 8100, and 12 400. These macro-azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate-polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc. 相似文献