全文获取类型
收费全文 | 637417篇 |
免费 | 10333篇 |
国内免费 | 5895篇 |
专业分类
化学 | 318783篇 |
晶体学 | 8922篇 |
力学 | 34417篇 |
综合类 | 339篇 |
数学 | 92488篇 |
物理学 | 198696篇 |
出版年
2021年 | 6482篇 |
2020年 | 7129篇 |
2019年 | 7898篇 |
2018年 | 14375篇 |
2017年 | 14551篇 |
2016年 | 15843篇 |
2015年 | 8353篇 |
2014年 | 12868篇 |
2013年 | 26845篇 |
2012年 | 24318篇 |
2011年 | 32289篇 |
2010年 | 22983篇 |
2009年 | 22975篇 |
2008年 | 29272篇 |
2007年 | 30973篇 |
2006年 | 21153篇 |
2005年 | 21820篇 |
2004年 | 18873篇 |
2003年 | 17558篇 |
2002年 | 16489篇 |
2001年 | 16367篇 |
2000年 | 12820篇 |
1999年 | 9854篇 |
1998年 | 8620篇 |
1997年 | 8292篇 |
1996年 | 7915篇 |
1995年 | 7065篇 |
1994年 | 7095篇 |
1993年 | 6777篇 |
1992年 | 7054篇 |
1991年 | 7518篇 |
1990年 | 7234篇 |
1989年 | 7074篇 |
1988年 | 6833篇 |
1987年 | 6595篇 |
1986年 | 6333篇 |
1985年 | 7921篇 |
1984年 | 8253篇 |
1983年 | 6972篇 |
1982年 | 7240篇 |
1981年 | 6708篇 |
1980年 | 6377篇 |
1979年 | 6944篇 |
1978年 | 7183篇 |
1977年 | 6997篇 |
1976年 | 7056篇 |
1975年 | 6730篇 |
1974年 | 6553篇 |
1973年 | 6918篇 |
1972年 | 5094篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Filatova S. M. Guseva M. K. Bodrova T. G. Parshina D. V. Budanova U. A. Sebyakin Yu. L. 《Russian Journal of General Chemistry》2022,91(1):S13-S23
Russian Journal of General Chemistry - The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial... 相似文献
32.
Knyazev Yu. V. Kazak N. V. Gavrichkov V. A. Polukeev S. I. Ovchinnikov S. G. 《JETP Letters》2022,116(8):567-573
JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and... 相似文献
33.
Varfolomeev S. D. Panin A. A. Semenova N. A. Ublinskiy M. V. Akhadov T. A. Bykov V. I. Tsybenova S. B. 《Russian Chemical Bulletin》2022,71(3):591-594
A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.
相似文献34.
Russian Journal of Organic Chemistry - A highly efficient green protocol has been proposed for the synthesis of symmetrical S-aryl arenesulfonothioates by irradiation of N-hydroxy arenesulfonamides... 相似文献
35.
Siberian Mathematical Journal - Let $ \{(A_{i},B_{i})\}_{i=1}^{m} $ be a set pair system. Füredi, Gyárfás, and Király called it $ 1 $ -cross intersecting if $... 相似文献
36.
Mathematical Notes - Subspaces of the space of analytic functions on a convex domain in the complex plane that are invariant with respect to the differentiation operator are studied. The problem of... 相似文献
37.
Hao Lu Xiaodong Wang Hang Wang Andong Zhang Xinming Zheng Na Yu Zheng Tang Xinjun Xu Yahui Liu Ya-Nan Chen Zhishan Bo 《中国科学:化学(英文版)》2022,65(3):594-601
Three nonfused ring electron acceptors (NFREAs) TTC6,TT-C8T and TT-TC8 were purposefully designed and synthesized.The molecular geometry can be adjusted by the steric hindrance of lateral substituents.According to the DFT calculations,from TTC6 to TT-C8T and TT-TC8,planarity of the molecular backbone is gradually improved,accompanying with the enhancing of intramolecular charge transfer effect.As for TT-TC8,the two phenyl substituents are almost perpendicular to the molecular backbone,which endues the acceptor with good solubility and suppresses it to form over-aggregation.Multidirectional regular molecular orientation and closer molecular stacking are formed in TT-TC8 film.As a result,TT-TC8 based devices afford the highest PCE of 13.13%,which is much higher than that of TTC6 (4.41%) and TT-C8T (10.42%) and among the highest PCE values based on NFREAs. 相似文献
38.
Mohammad A. Khalilzadeh Soo Young Kim Ho Won Jang Rafael Luque Rajender S. Varma Richard A. Venditti Mohammadreza Shokouhimehr 《Materials Today Chemistry》2022
The requirement of green and sustainable materials to prepare heterogeneous catalysts has intensified for practical reasons over the past few decades. Carbohydrates are possibly the most plentiful and renewable organic materials in nature with inimitable physiochemical properties, plausible low-cost and large-scale production, and sustainability features could be exploited in the generation of nanostructured heterogeneous catalysts. This review article outlines the organic transformations catalyzed by diverse carbohydrate-based nanostructured catalysts in greener and environmentally friendly processes. Selected examples are highlighted for a variety of organic reactions exploiting the proposed catalysts’ reactivity and reusability, and interactions with the intrinsic nature of the applied carbohydrate supports; advantages and speculated challenges of the introduced catalysts are deliberated as well. 相似文献
39.
40.
Machado J. A. Tenreiro Rocha-Neves J. M. Azevedo Filipe Andrade J. P. 《Nonlinear dynamics》2021,106(2):1525-1555
Nonlinear Dynamics - Given a data-set of Ribonucleic acid (RNA) sequences we can infer the phylogenetics of the samples and tackle the information for scientific purposes. Based on current data and... 相似文献