全文获取类型
收费全文 | 5517篇 |
免费 | 705篇 |
国内免费 | 804篇 |
专业分类
化学 | 3988篇 |
晶体学 | 46篇 |
力学 | 426篇 |
综合类 | 48篇 |
数学 | 782篇 |
物理学 | 1736篇 |
出版年
2024年 | 13篇 |
2023年 | 94篇 |
2022年 | 126篇 |
2021年 | 203篇 |
2020年 | 218篇 |
2019年 | 217篇 |
2018年 | 175篇 |
2017年 | 177篇 |
2016年 | 220篇 |
2015年 | 211篇 |
2014年 | 257篇 |
2013年 | 399篇 |
2012年 | 455篇 |
2011年 | 481篇 |
2010年 | 348篇 |
2009年 | 295篇 |
2008年 | 345篇 |
2007年 | 294篇 |
2006年 | 284篇 |
2005年 | 281篇 |
2004年 | 208篇 |
2003年 | 194篇 |
2002年 | 178篇 |
2001年 | 165篇 |
2000年 | 135篇 |
1999年 | 160篇 |
1998年 | 115篇 |
1997年 | 102篇 |
1996年 | 98篇 |
1995年 | 88篇 |
1994年 | 59篇 |
1993年 | 67篇 |
1992年 | 55篇 |
1991年 | 50篇 |
1990年 | 43篇 |
1989年 | 38篇 |
1988年 | 25篇 |
1987年 | 17篇 |
1986年 | 17篇 |
1985年 | 18篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1970年 | 4篇 |
排序方式: 共有7026条查询结果,搜索用时 31 毫秒
1.
2.
Hongjin Wang Tengfei Long Hao Zhang Meng Li Qi Sun Xin Zhai Lixin Sun 《Biomedical chromatography : BMC》2022,36(4):e5301
3,4-Difluorobenzyl(1-ethyl-5-(4-((4-hydroxypiperidin-1-yl)-methyl)thiazol-2-yl)-1H-indol-3-yl)carbamate (NAI59), a small molecule with outstanding therapeutic effectiveness to anti-pulmonary fibrosis, was developed as an autotaxin inhibitor candidate compound. To evaluate the pharmacokinetics and plasma protein binding of NAI59, a UPLC–MS/MS method was developed to quantify NAI59 in plasma and phosphate-buffered saline. The calibration curve linearity ranged from 9.95 to 1990.00 ng/mL in plasma. The accuracy was −6.8 to 5.9%, and the intra- and inter-day precision was within 15%. The matrix effect and recovery, as well as dilution integrity, were within the criteria. The chromatographic and mass spectrometric conditions were also feasible to determine phosphate-buffered saline samples, and it has been proved that this method exhibits good precision and accuracy in the range of 9.95–497.50 ng/mL in phosphate-buffered saline. This study is the first to determine the pharmacokinetics, absolute bioavailability, and plasma protein binding of NAI59 in rats using this established method. Therefore, the pharmacokinetic profiles of NAI59 showed a dose-dependent relationship after oral administration, and the absolute bioavailability in rats was 6.3%. In addition, the results of protein binding showed that the combining capacity of NAI59 with plasma protein attained 90% and increased with the increase in drug concentration. 相似文献
3.
4.
In this research article, we describe the synthesis and characterization of mononuclear and dinuclear Cu complexes bound by a family of tridentate redox-active ligands with tunable H-bonding donors. The mononuclear Cu-anion complexes were oxidized to the corresponding “high-valent” intermediates by oxidation of the redox-active ligand. These species were capable of oxidizing phenols with weak O−H bonds via H-atom abstraction. Thermodynamic analysis of the H-atom abstractions, which included reduction potential measurements, pKa determination and kinetic studies, revealed that modification of the anion coordinated to the Cu and changes in the H-bonding donor did not lead to major differences in the reactivity of the “high-valent” CuY complexes (Y: hydroxide, phenolate and acetate), which indicated that the tridentate ligand scaffold acts as the H+ and e− acceptor. 相似文献
5.
6.
This paper through discussing subdifferentiability and convexity of convex functions shows that a Banach space admits an equivalent
uniformly [locally uniformly, strictly] convex norm if and only if there exists a continuous uniformly [locally uniformly,
strictly] convex function on some nonempty open convex subset of the space and presents some characterizations of super-reflexive
Banach spaces.
Supported by NSFC 相似文献
7.
L. Tong Y. Tian Q. Y. Wang Y. S. Ling 《International Journal of Infrared and Millimeter Waves》2006,27(9):1307-1314
The paper introduces a special system calibration technology in s-parameters measurement of microwave and millimeter wave
devices. The 8-term errors module is built by analyzing the signals flowing in the measurement system. Then the calibration
technology using non-standard kits is designed on the base. Finally, the experiment using the calibration technology is introduced. 相似文献
8.
A lithium(I) coordination polymer has been formed from LiClO4 and the 2,2′‐bipyrimidine (bpym) ligand in which each square pyramidal lithium(I) atom is coordinated in the basal plane by four nitrogen donor atoms derived from two bpym ligands and one water molecule at the apical position. These are connected into a layer structure via hydrogen‐bonding interactions involving the perchlorate anions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
9.
A locally convex space is said to be a Gateaux differentiability space (GDS)provided every continuous convex function defined on a nonempty convex open subset D of the space is densely Gateaux differentiable in D.This paper shows that the product of a GDS and a family of separable Frechet spaces is a GDS,and that the product of a GDS and an arbitrary locally convex space endowed with the weak topology is a GDS. 相似文献
10.