全文获取类型
收费全文 | 203340篇 |
免费 | 1492篇 |
国内免费 | 427篇 |
专业分类
化学 | 105023篇 |
晶体学 | 3400篇 |
力学 | 10272篇 |
综合类 | 10篇 |
数学 | 21888篇 |
物理学 | 64666篇 |
出版年
2021年 | 1982篇 |
2020年 | 2025篇 |
2019年 | 2575篇 |
2018年 | 3666篇 |
2017年 | 3678篇 |
2016年 | 4827篇 |
2015年 | 2356篇 |
2014年 | 4333篇 |
2013年 | 8623篇 |
2012年 | 6869篇 |
2011年 | 8073篇 |
2010年 | 6480篇 |
2009年 | 6668篇 |
2008年 | 7661篇 |
2007年 | 7610篇 |
2006年 | 6714篇 |
2005年 | 5941篇 |
2004年 | 5655篇 |
2003年 | 5178篇 |
2002年 | 5164篇 |
2001年 | 5616篇 |
2000年 | 4146篇 |
1999年 | 3141篇 |
1998年 | 2705篇 |
1997年 | 2758篇 |
1996年 | 2543篇 |
1995年 | 2219篇 |
1994年 | 2330篇 |
1993年 | 2229篇 |
1992年 | 2528篇 |
1991年 | 2645篇 |
1990年 | 2553篇 |
1989年 | 2628篇 |
1988年 | 2531篇 |
1987年 | 2554篇 |
1986年 | 2413篇 |
1985年 | 3039篇 |
1984年 | 3103篇 |
1983年 | 2596篇 |
1982年 | 2564篇 |
1981年 | 2530篇 |
1980年 | 2336篇 |
1979年 | 2709篇 |
1978年 | 2672篇 |
1977年 | 2875篇 |
1976年 | 2873篇 |
1975年 | 2664篇 |
1974年 | 2603篇 |
1973年 | 2712篇 |
1972年 | 2088篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
JETP Letters - A new approach to search for axions in the storage ring experiments, applicable at a short coherence time of the in-plane polarization as is the case for protons is discussed. The... 相似文献
2.
Gaineev A. M. Galkina I. V. Davletshin R. R. Davletshina N. V. Kuznetsov N. O. Grishaev D. Yu. Shulayeva M. P. Pozdeev O. K. 《Russian Journal of General Chemistry》2022,92(7):1208-1213
Russian Journal of General Chemistry - Aminophosphabetaines, i.e., isobutyl {[alkyl(dimethyl)ammonio]methyl}phosphonates with higher alkyl substituents at the nitrogen atom, were obtained by a... 相似文献
3.
Mamatkulova N. M. Mukarramov N. I. Sasmakov S. A. Khidirova N. K. 《Chemistry of Natural Compounds》2022,58(4):726-727
Chemistry of Natural Compounds - 相似文献
4.
Petrov P. A. Filippova E. A. Kompankov N. B. Sukhikh T. S. Sokolov M. N. 《Journal of Structural Chemistry》2022,63(3):470-475
Journal of Structural Chemistry - A new polymorph of the [ReCl3(MeCN)(PPh3)2] complex is synthesized and characterized by single crystal X-ray diffraction (XRD). Its recrystallization from the... 相似文献
5.
Chetan Bhadaliya Bala Krishna Panigrahy Dipanjan Goswami Sovan Maiti Sanjay Jagannath Gurule Arshad H. Khuroo 《Biomedical chromatography : BMC》2022,36(4):e5337
A selective, highly sensitive, precise, and novel bioanalytical method has been developed and validated to quantify sinococuline, an active constituent present in the phytopharmaceutical drug product containing Cocculus hirsutus plant extract, in vivo. Chromatographic separation was achieved on a Luna Omega Polar-C18 bonded analytical column maintained at 45°C. The isocratic mobile phase consisted of methanol and ammonium formate buffer (60:40, v/v) at acidic pH with a low flow rate of 0.250 mL/min. Detection was performed on an API 4000 mass spectrometer using electrospray ionization in positive polarity and multiple reaction monitoring mode to achieve a lower limit of quantification of 1.50 ng/mL. Excellent accuracy and precision were obtained after extracting the analyte from plasma samples using a chemical analogue as an internal standard in the absence of an isotope-labeled compound. The extraction efficacy was evidenced from recovery study, and the analyte was found to be stable in plasma. Validation study demonstrated linearity with coefficient of correlation, r ≥ 0.99, and minimal matrix effect. This bioanalytical method was successfully applied to evaluate pharmacokinetic parameters of sinococuline from a phase I clinical trial of an aqueous extract of C. hirsutus in healthy human volunteers. 相似文献
6.
Russian Chemical Bulletin - New representatives of (O-Si)-chelate compounds, N-(fluorosilyl)methyl derivatives of N-methylacetamide, N-methylbenzamide, N-phenylacetamide, and N-phenylbenzamide,... 相似文献
7.
Russian Journal of General Chemistry - A mechanochemical method was developed for the synthesis of ferromagnetic Pd–Fe–Co–Ni composites based on the natural biopolymer chitosan,... 相似文献
8.
Yuki Shintani Taku Ohtomi Dr. Aya Shibata Dr. Yoshiaki Kitamura Koichiro M. Hirosawa Prof. Kenichi G. N. Suzuki Prof. Masato Ikeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104421
Aqueous self-assembly of short peptides has attracted growing attention for the construction of supramolecular materials for various bioapplications. Herein, we describe how the thermolysin-assisted biocatalytic construction of a dipeptide hydrazide from an N-protected amino acid and an amino acid hydrazide leads to the formation of thermally stable supramolecular hydrogels. In addition, we demonstrate the post-assembly modification of the supramolecular architectures constructed in situ tethering hydrazide groups as a chemical handle by means of fluorescence imaging. 相似文献
9.
Journal of Structural Chemistry - Atomic and electronic structures of cyclic organosilicon compound 9,9,10,10-tetraethynyl-9,10-dihydrodisilaanthracene are studied by the density functional theory.... 相似文献
10.
Tsyganova S. I. Fetisova O. Yu. Mazurova E. N. Taran O. P. Kuznetsov B. N. 《Russian Journal of Applied Chemistry》2022,95(3):408-416
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed.... 相似文献