全文获取类型
收费全文 | 30204篇 |
免费 | 810篇 |
国内免费 | 170篇 |
专业分类
化学 | 20377篇 |
晶体学 | 170篇 |
力学 | 730篇 |
数学 | 5353篇 |
物理学 | 4554篇 |
出版年
2022年 | 206篇 |
2021年 | 389篇 |
2020年 | 416篇 |
2019年 | 452篇 |
2018年 | 374篇 |
2017年 | 309篇 |
2016年 | 649篇 |
2015年 | 585篇 |
2014年 | 634篇 |
2013年 | 1625篇 |
2012年 | 1429篇 |
2011年 | 1837篇 |
2010年 | 953篇 |
2009年 | 948篇 |
2008年 | 1568篇 |
2007年 | 1585篇 |
2006年 | 1548篇 |
2005年 | 1499篇 |
2004年 | 1284篇 |
2003年 | 1098篇 |
2002年 | 979篇 |
2001年 | 447篇 |
2000年 | 363篇 |
1999年 | 309篇 |
1998年 | 334篇 |
1997年 | 362篇 |
1996年 | 404篇 |
1995年 | 277篇 |
1994年 | 324篇 |
1993年 | 309篇 |
1992年 | 279篇 |
1991年 | 292篇 |
1990年 | 237篇 |
1989年 | 266篇 |
1988年 | 272篇 |
1987年 | 237篇 |
1986年 | 236篇 |
1985年 | 344篇 |
1984年 | 389篇 |
1983年 | 260篇 |
1982年 | 402篇 |
1981年 | 380篇 |
1980年 | 358篇 |
1979年 | 365篇 |
1978年 | 371篇 |
1977年 | 336篇 |
1976年 | 311篇 |
1975年 | 294篇 |
1974年 | 275篇 |
1973年 | 272篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
2.
3.
4.
Journal of Computer-Aided Molecular Design - Accurate predictions of acid dissociation constants are essential to rational molecular design in the pharmaceutical industry and elsewhere. There has... 相似文献
5.
6.
Robert G. W. Anderson 《Ambix》2015,62(4):333-344
Following colonisation of South America by the Spanish, many new naturally occurring substances were sent to Europe. One of these was the silvery, unreactive metal, platinum, discovered in New Grenada in the mid-eighteenth century. It was often found in granular form, associated with gold, and the challenge to chemists was to refine it, produce it as wire or sheet, and determine its chemical properties. This interested the professor of chemistry at the University of Edinburgh, Joseph Black, who was able to obtain samples from London-based Spanish contacts, particularly Ignacio Luzuriaga. This paper examines how Black transmitted his knowledge of the metal to large numbers of students attending his annual course. 相似文献
7.
8.
9.
Hui Li Jian Liu Juan Zhao Huiting He Dr. Dabo Jiang Prof. Steven Robert Kirk Prof. Qiong Xu Dr. Xianxiang Liu Prof. Dulin Yin 《ChemistryOpen》2021,10(4):477-485
A series of tetraimidazolium salts with different anions was prepared and applied in the isomerization of β-pinene oxide. After examining the activity of different catalysts, a remarkable enhancement of the selectivity of perillyl alcohol (47 %) was obtained over [PEimi][HNO3]4 under mild reaction conditions and using DMSO as the solvent. Furthermore, noncovalent interactions between solvent molecules and the catalyst were found by FT-IR spectroscopy and confirmed by computational chemistry. The homogeneous catalyst showed excellent stability and was reused up to six times without significant loss. 相似文献
10.
Avramenko Andriy A. Shevchuk Igor V. Dmitrenko Nataliia P. Skitsko Ivan F. 《Journal of Thermal Analysis and Calorimetry》2022,147(22):12709-12719
Journal of Thermal Analysis and Calorimetry - The paper focuses on the analytical analysis of the propagation of a normal shock wave in an adiabatic gas flow with nanoparticles. A modified... 相似文献