全文获取类型
收费全文 | 2075篇 |
免费 | 47篇 |
国内免费 | 3篇 |
专业分类
化学 | 1140篇 |
晶体学 | 11篇 |
力学 | 53篇 |
数学 | 294篇 |
物理学 | 627篇 |
出版年
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 23篇 |
2018年 | 20篇 |
2017年 | 11篇 |
2016年 | 40篇 |
2015年 | 27篇 |
2014年 | 35篇 |
2013年 | 88篇 |
2012年 | 78篇 |
2011年 | 71篇 |
2010年 | 34篇 |
2009年 | 24篇 |
2008年 | 73篇 |
2007年 | 75篇 |
2006年 | 73篇 |
2005年 | 88篇 |
2004年 | 73篇 |
2003年 | 83篇 |
2002年 | 67篇 |
2001年 | 61篇 |
2000年 | 60篇 |
1999年 | 48篇 |
1998年 | 22篇 |
1997年 | 41篇 |
1996年 | 42篇 |
1995年 | 32篇 |
1994年 | 27篇 |
1993年 | 33篇 |
1992年 | 38篇 |
1991年 | 29篇 |
1990年 | 51篇 |
1989年 | 39篇 |
1988年 | 39篇 |
1987年 | 24篇 |
1986年 | 29篇 |
1985年 | 42篇 |
1984年 | 38篇 |
1983年 | 30篇 |
1982年 | 36篇 |
1981年 | 28篇 |
1980年 | 28篇 |
1979年 | 21篇 |
1978年 | 27篇 |
1977年 | 28篇 |
1976年 | 20篇 |
1975年 | 26篇 |
1974年 | 21篇 |
1973年 | 31篇 |
1971年 | 12篇 |
排序方式: 共有2125条查询结果,搜索用时 281 毫秒
81.
This paper extends some properties of the generalized complementary basic matrices, in particular, in a combinatorial direction. These include inheritance (such as for Alternating Sign Matrices), spectral, and sign pattern matrix (including sign nonsingularity) properties. 相似文献
82.
Accreditation and Quality Assurance - When reporting expanded uncertainty, rounding the number of significant figures can affect the associated level of confidence. A simple numerical method is... 相似文献
83.
84.
85.
86.
Philip J. Hammond C. Dennis Hall 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):351-353
Abstract Cis-1-alkyl (or aryl)-2,5-dimethyl-3-phospholens isomerize to the trans-isomers in deuteriochloroform and the isomerization is probably due to small quantities of phosgene in the solvent. 相似文献
87.
Dzmitry Padhorny David R. Hall Hanieh Mirzaei Artem B. Mamonov Mohammad Moghadasi Andrey Alekseenko Dmitri Beglov Dima Kozakov 《Journal of computer-aided molecular design》2018,32(1):225-230
Fast Fourier transform (FFT) based approaches have been successful in application to modeling of relatively rigid protein–protein complexes. Recently, we have been able to adapt the FFT methodology to treatment of flexible protein–peptide interactions. Here, we report our latest attempt to expand the capabilities of the FFT approach to treatment of flexible protein–ligand interactions in application to the D3R PL-2016-1 challenge. Based on the D3R assessment, our FFT approach in conjunction with Monte Carlo minimization off-grid refinement was among the top performing methods in the challenge. The potential advantage of our method is its ability to globally sample the protein–ligand interaction landscape, which will be explored in further applications. 相似文献
88.
89.
90.
Mainly through the extensive investigations of Nakagawa and coworkers, nickel peroxide has emerged as a powerful oxidant for organic compounds. For example, it has been used for the oxidation of alcohols to aldehydes or carboxylic acids,2,3 allylic hydroxyl (selectively) to the carbonyl group,4 α-ketols to α-diketones,5 α-glycols, α-ketols, α-hydroxyl and α-keto acids to cleavage products,6 aldehydes to amides or nitriles in the presence of ammonia,7 phenols to quinones,8,9 certain Schiff bases to benzoxazoles,10 amines to azo compounds or nitriles,11,12 diarylamines to hydrazines,13 carbazoles to dimers and trimers,14 hydrazones to diazo compounds,15,16 1-aminobenzotriazole to benzyne,17 N-substituted hydroxylamines to azoxy compounds,18 phenylacetonitrile to dimeric products,19 a thiouracil to a uracil derivative,20 thiols to disulfides and sulfides to sulfones,21 N-substituted phenothiazines to sulfoxides and sulfones,21 haloforms to hexahaloethanes.23 相似文献