全文获取类型
收费全文 | 351581篇 |
免费 | 18737篇 |
国内免费 | 9711篇 |
专业分类
化学 | 200835篇 |
晶体学 | 4607篇 |
力学 | 17458篇 |
综合类 | 521篇 |
数学 | 39419篇 |
物理学 | 117189篇 |
出版年
2022年 | 3233篇 |
2021年 | 4734篇 |
2020年 | 5901篇 |
2019年 | 5704篇 |
2018年 | 6172篇 |
2017年 | 5825篇 |
2016年 | 8847篇 |
2015年 | 6745篇 |
2014年 | 9299篇 |
2013年 | 17103篇 |
2012年 | 15906篇 |
2011年 | 18079篇 |
2010年 | 12504篇 |
2009年 | 12133篇 |
2008年 | 14925篇 |
2007年 | 14421篇 |
2006年 | 13519篇 |
2005年 | 11773篇 |
2004年 | 10255篇 |
2003年 | 8947篇 |
2002年 | 8681篇 |
2001年 | 9019篇 |
2000年 | 7193篇 |
1999年 | 6132篇 |
1998年 | 5416篇 |
1997年 | 5363篇 |
1996年 | 5106篇 |
1995年 | 4627篇 |
1994年 | 4610篇 |
1993年 | 4157篇 |
1992年 | 4497篇 |
1991年 | 4435篇 |
1990年 | 4224篇 |
1989年 | 3943篇 |
1988年 | 3926篇 |
1987年 | 3767篇 |
1986年 | 3603篇 |
1985年 | 4616篇 |
1984年 | 4782篇 |
1983年 | 3987篇 |
1982年 | 4101篇 |
1981年 | 3904篇 |
1980年 | 3870篇 |
1979年 | 3817篇 |
1978年 | 4137篇 |
1977年 | 4059篇 |
1976年 | 4127篇 |
1975年 | 3796篇 |
1974年 | 3862篇 |
1973年 | 4004篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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
12.
Song Zhang Luke A. Galuska Xiaodan Gu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(7):1108-1129
Thin films with a nanometer-scale thickness are of great interest to both scientific and industrial communities due to their numerous applications and unique behaviors different from the bulk. However, the understanding of thin-film mechanics is still greatly hampered due to their intrinsic fragility and the lack of commercially available experimental instruments. In this review, we first discuss the progression of thin-film mechanical testing methods based on the supporting substrate: film-on-solid substrate method, film-on-water tensile tests, and water-assisted free-standing tensile tests. By comparing past studies on a model polymer, polystyrene, the effect of different substrates and confinement effect on the thin-film mechanics is evaluated. These techniques have generated fruitful scientific knowledge in the field of organic semiconductors for the understanding of structure–mechanical property relationships. We end this review by providing our perspective for their bright prospects in much broader applications and materials of interest. 相似文献
13.
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
14.
Tian Xiu-Zhi Yang Rui Ma Jia-Jia Ni Yong-Hao Deng Hai-Bo Dai Lei Tan Jiao-Jun Zhang Mei-Yun Jiang Xue 《高分子科学》2022,40(7):789-798
Chinese Journal of Polymer Science - Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments. Herein, polyurethane was... 相似文献
15.
16.
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
17.
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
18.
Gürbüzbalaban Mert Ruszczyński Andrzej Zhu Landi 《Journal of Optimization Theory and Applications》2022,194(3):1014-1041
Journal of Optimization Theory and Applications - We consider a distributionally robust formulation of stochastic optimization problems arising in statistical learning, where robustness is with... 相似文献
19.
Russian Journal of Applied Chemistry - In September 1975, the head of Russian electrochemists, Academician A.N. Frumkin (1895–1976), in his report at the XI Mendeleev Congress on General and... 相似文献
20.
Mathematical Programming - In this paper, we study the lower iteration complexity bounds for finding the saddle point of a strongly convex and strongly concave saddle point problem: $$\min _x\max... 相似文献