全文获取类型
收费全文 | 447900篇 |
免费 | 7069篇 |
国内免费 | 1883篇 |
专业分类
化学 | 241264篇 |
晶体学 | 6604篇 |
力学 | 19348篇 |
综合类 | 49篇 |
数学 | 52296篇 |
物理学 | 137291篇 |
出版年
2021年 | 4073篇 |
2020年 | 4625篇 |
2019年 | 4887篇 |
2018年 | 6238篇 |
2017年 | 6117篇 |
2016年 | 9546篇 |
2015年 | 6171篇 |
2014年 | 9198篇 |
2013年 | 21268篇 |
2012年 | 16674篇 |
2011年 | 20321篇 |
2010年 | 14222篇 |
2009年 | 14008篇 |
2008年 | 18348篇 |
2007年 | 18068篇 |
2006年 | 16760篇 |
2005年 | 14919篇 |
2004年 | 13843篇 |
2003年 | 12163篇 |
2002年 | 11967篇 |
2001年 | 13620篇 |
2000年 | 10275篇 |
1999年 | 8144篇 |
1998年 | 6785篇 |
1997年 | 6495篇 |
1996年 | 6266篇 |
1995年 | 5643篇 |
1994年 | 5541篇 |
1993年 | 5329篇 |
1992年 | 5954篇 |
1991年 | 6048篇 |
1990年 | 5744篇 |
1989年 | 5547篇 |
1988年 | 5575篇 |
1987年 | 5450篇 |
1986年 | 5167篇 |
1985年 | 6645篇 |
1984年 | 6767篇 |
1983年 | 5366篇 |
1982年 | 5432篇 |
1981年 | 5421篇 |
1980年 | 5008篇 |
1979年 | 5406篇 |
1978年 | 5538篇 |
1977年 | 5446篇 |
1976年 | 5378篇 |
1975年 | 4954篇 |
1974年 | 4930篇 |
1973年 | 4927篇 |
1972年 | 3480篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Mazurenko V. V. Kvashnin Y. O. Lichtenstein A. I. Katsnelson M. I. 《Journal of Experimental and Theoretical Physics》2021,132(4):506-516
Journal of Experimental and Theoretical Physics - Dzyaloshinskii–Moriya interaction, DMI in short, represents an antisymmetric type of magnetic interactions that favor orthogonal orientation... 相似文献
2.
Chuprin A. S. Belova S. A. Bugaenko M. G. Vologzhanina A. V. Loktev A. S. Voloshin Ya. Z. Buznik V. M. Dedov A. G. 《Kinetics and Catalysis》2022,63(1):108-116
Kinetics and Catalysis - A new ruthenium(II) cage complex with polar terminal groups in the apical substituents has been synthesized; the molecular design of the complex contributes to the... 相似文献
3.
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
4.
Sakhautdinova G. F. Sakhautdinov I. M. Mustafin A. G. Yunusov M. S. 《Chemistry of Natural Compounds》2022,58(1):185-186
Chemistry of Natural Compounds - 相似文献
5.
Dan Chen Kaixin Du Xiaochen Niu Hongwei Zhang Xue Zhang Yu Tang Jianchun Zhao 《Biomedical chromatography : BMC》2022,36(3):e5288
Amlexanox, an anti-inflammatory and anti-allergic agent, has been widely used clinically for the treatment of canker sores, asthma, and allergic rhinitis. Recently, amlexanox has received considerable attention in curing nonalcoholic fatty liver diseases and hepatitis virus infection. Herein, we first established a sensitive high-performance liquid chromatography-tandem mass spectrum (LC–MS/MS) method for the determination of amlexanox in rat plasma. Propranolol was used as the internal standard (IS). Using a simple protein precipitation method, the amlexanox and IS were separated with Capcell Pak C18 column (2.0 × 50 mm, 5 μm) and eluted with water and acetonitrile each containing 0.1% formic acid using gradient elution condition at a flow rate of 0.4 mL·min−1. Amlexanox and IS were detected by a triple quadrupole mass in multiple reactive monitoring (MRM) under the transitions of m/z 299.2 → 281.2 and m/z 259.9 → 116.1 with positive electrospray ionization, respectively. The calibration curves of amlexanox were established with the range of 50 to 2000 ng·mL−1 (r2 > 0.99). The validation method consisted of selectivity, accuracy, precision, carryover effect, matrix effect, recovery, dilution effect, and stability. The fully validated method was successfully applied to the pharmacokinetic study of amlexanox in Wistar rats. 相似文献
6.
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
7.
Romanenko G. V. Fokin S. V. Bogomyakov A. S. Zueva E. M. Ovcharenko V. I. 《Journal of Structural Chemistry》2022,63(3):441-450
Journal of Structural Chemistry - The structures of Ni(II), Cu(II), and Zn(II) complexes with anions of 2,5-pyrrolyl-disubstituted nitronyl nitroxide (L1) and iminonitroxide (L2) diradicals (HL1 is... 相似文献
8.
Hassan E. A. M. Elabid A. E. A. Bashier E. O. Elagib T. H. H. 《Mechanics of Composite Materials》2022,58(2):261-270
Mechanics of Composite Materials - Carbon fiber (CF)/ polyamide (PA6) composites are one of the most promising thermoplastic materials for automobile applications. However, the interfacial... 相似文献
9.
In the pursuit to enlarge the library of polyimide materials for energy applications, new polyimide/MWCNTs composite films have been developed by MWCNTs-assisted polycondensation reaction of a hydroxyl and triphenylmethane-containing diamine with benzophenone tetracarboxylic dianhydride targeting to highlight their electrical storage capability as flexible electrodes in micro-supercapacitors (mSCs). The Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance, UV–vis, fluorescence, and Raman spectroscopies were used to demonstrate the evolution of interfacial interactions between MWCNTs and the precursors (diamine monomer and intermediate polyamidic acid) and polyimide matrix that proved to be the origin of MWCNTs homogeneous dispersion. Thus, composite films incorporating 1, 3, 5, and 10 w.t.% MWCNTs were obtained and thoroughly investigated with regard to their morphology, mechanical behavior, thermal stability, and electrical conductivity. The electrochemical performance of these composites was first analyzed in a classical three-electrode cell by cyclic voltammetry and galvanostatic charge-discharge in both aqueous and organic electrolyte systems. By far, the best electrical storage capacity was obtained with the composite polyimide film containing 10% MWCNTs that was further used as both active material and current collector in a flexible symmetric mSC realized by a straightforward and low-cost procedure. In the attempt to better exploit the advantages of this composite film, it was layered with a graphite-containing paint and tested as an electrode in a flexible mSC, which provided satisfactory results. To our knowledge, this is the first report on the electrical charge storage capability of a polyimide/MWCNTs free-standing film as a flexible electrode in mSCs, which do not require time- and resource-consuming processing steps. 相似文献
10.
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