全文获取类型
收费全文 | 225672篇 |
免费 | 3298篇 |
国内免费 | 618篇 |
专业分类
化学 | 126086篇 |
晶体学 | 3419篇 |
力学 | 8489篇 |
综合类 | 4篇 |
数学 | 24310篇 |
物理学 | 67280篇 |
出版年
2018年 | 1654篇 |
2016年 | 3170篇 |
2015年 | 2445篇 |
2014年 | 3239篇 |
2013年 | 9559篇 |
2012年 | 6649篇 |
2011年 | 8294篇 |
2010年 | 5326篇 |
2009年 | 5124篇 |
2008年 | 7585篇 |
2007年 | 7703篇 |
2006年 | 7287篇 |
2005年 | 6573篇 |
2004年 | 5907篇 |
2003年 | 5182篇 |
2002年 | 5053篇 |
2001年 | 6304篇 |
2000年 | 4898篇 |
1999年 | 3861篇 |
1998年 | 3053篇 |
1997年 | 3092篇 |
1996年 | 3130篇 |
1995年 | 2884篇 |
1994年 | 2795篇 |
1993年 | 2767篇 |
1992年 | 3164篇 |
1991年 | 2936篇 |
1990年 | 2913篇 |
1989年 | 2909篇 |
1988年 | 2840篇 |
1987年 | 2849篇 |
1986年 | 2646篇 |
1985年 | 3648篇 |
1984年 | 3645篇 |
1983年 | 3020篇 |
1982年 | 3227篇 |
1981年 | 3156篇 |
1980年 | 3068篇 |
1979年 | 3163篇 |
1978年 | 3441篇 |
1977年 | 3248篇 |
1976年 | 3126篇 |
1975年 | 2972篇 |
1974年 | 2920篇 |
1973年 | 2934篇 |
1972年 | 1864篇 |
1968年 | 2035篇 |
1967年 | 2228篇 |
1966年 | 2038篇 |
1965年 | 1606篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
11.
Clemens G. Raab Georg Regensburger Jamal Hossein Poor 《Journal of Pure and Applied Algebra》2021,225(5):106564
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials. 相似文献
12.
Analysis Mathematica - We introduce and study the k-Hankel Gabor transform. We investigate the localization operators for this transform. In particular, we study their trace class properties and we... 相似文献
13.
14.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
15.
Vasile M. Loots H. Vercammen L. Bruggeman M. Verrezen F. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(8):3349-3357
Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine... 相似文献
16.
17.
In a 2:2 reaction with silver(I) chloride or bromide, 1,5-bis(1-phospholano)pentane ( 1a ) afforded frame-like macrocyclic structures, with intra- ( 2 , Cl) or intermolecular ( 3 , Br) halido bridges. In contrast, 1,7-bis(1-phospholano)heptane ( 1b ) formed coordination polymers 4a (Cl) and 4b (Br) with bridging bis-phospholane and halido ligands. A unique paddle wheel-type metallacryptand structure 5 was obtained from 1a and silver(I) bromide in a 2:3 reaction (M:L). All complexes were fully characterized by NMR, IR spectroscopy, mass spectrometry, and X-ray crystallography. 相似文献
18.
Laurens Kooijman Dr. Matthias Schuster Christian Baumann Simon Jurt Dr. Frank Löhr Dr. Boris Fürtig Prof. Dr. Peter Güntert Prof. Dr. Oliver Zerbe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21151-21158
To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR. 相似文献
19.
20.
The European Physical Journal Special Topics - The removal of suspended particles from the interior of a thermocapillary liquid bridge via a finite-particle-size effect restricting the particle... 相似文献