全文获取类型
收费全文 | 30176篇 |
免费 | 1079篇 |
国内免费 | 74篇 |
专业分类
化学 | 19555篇 |
晶体学 | 189篇 |
力学 | 650篇 |
综合类 | 1篇 |
数学 | 5535篇 |
物理学 | 5399篇 |
出版年
2023年 | 199篇 |
2022年 | 285篇 |
2021年 | 427篇 |
2020年 | 501篇 |
2019年 | 510篇 |
2018年 | 614篇 |
2017年 | 548篇 |
2016年 | 1164篇 |
2015年 | 916篇 |
2014年 | 1004篇 |
2013年 | 1963篇 |
2012年 | 1991篇 |
2011年 | 2007篇 |
2010年 | 1194篇 |
2009年 | 1193篇 |
2008年 | 1750篇 |
2007年 | 1773篇 |
2006年 | 1568篇 |
2005年 | 1415篇 |
2004年 | 1321篇 |
2003年 | 971篇 |
2002年 | 839篇 |
2001年 | 598篇 |
2000年 | 545篇 |
1999年 | 415篇 |
1998年 | 302篇 |
1997年 | 293篇 |
1996年 | 375篇 |
1995年 | 247篇 |
1994年 | 287篇 |
1993年 | 227篇 |
1992年 | 247篇 |
1991年 | 218篇 |
1990年 | 225篇 |
1989年 | 186篇 |
1988年 | 177篇 |
1987年 | 166篇 |
1986年 | 169篇 |
1985年 | 251篇 |
1984年 | 251篇 |
1983年 | 164篇 |
1982年 | 175篇 |
1981年 | 176篇 |
1980年 | 172篇 |
1979年 | 123篇 |
1978年 | 132篇 |
1977年 | 123篇 |
1976年 | 101篇 |
1975年 | 95篇 |
1973年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
51.
J. Gróh 《Colloid and polymer science》1941,94(1):1-10
Ohne Zusammenfassung
Die mitgeteilten Untersuchungen haben wir mit Unterstützung der Ungarischen wissenschaftlichen „Széchenyi“-Gesellschaft durchgeführt. 相似文献
52.
Miklós Csörgő 《Periodica Mathematica Hungarica》2005,50(1-2):1-27
Summary This article provides a glimpse of some of the highlights of the joint work of Endre Csáki and Pál Révész since 1979. The topics of this short exploration of the rich stochastic milieu of this inspiring collaboration revolve around Brownian motion, random walks and their long excursions, local times and additive functionals, iterated processes, almost sure local and global central limit theorems, integral functionals of geometric stochastic processes, favourite sites--favourite values and jump sizes for random walk and Brownian motion, random walking in a random scenery, and large void zones and occupation times for coalescing random walks. 相似文献
53.
Mrio J. Edmundo 《Mathematical Logic Quarterly》2005,51(6):639-641
We show that if G is a definably compact, definably connected definable group defined in an arbitrary o‐minimal structure, then G is divisible. Furthermore, if G is defined in an o‐minimal expansion of a field, k ∈ ? and pk : G → G is the definable map given by pk (x ) = xk for all x ∈ G , then we have |(pk )–1(x )| ≥ kr for all x ∈ G , where r > 0 is the maximal dimension of abelian definable subgroups of G . (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
54.
55.
Robert Jerrard Alberto Montero Peter Sternberg 《Communications in Mathematical Physics》2004,249(3):549-577
We establish the existence of locally minimizing vortex solutions to the full Ginzburg-Landau energy in three dimensional simply-connected domains with or without the presence of an applied magnetic field. The approach is based upon the theory of weak Jacobians and applies to nonconvex sample geometries for which there exists a configuration of locally shortest line segments with endpoints on the boundary.Research partially supported by NSERC grant number 261955 相似文献
56.
57.
Alberto Plaza Sonia Piacente Angela Perrone Arafa Hamed Cosimo Pizza Giuseppe Bifulco 《Tetrahedron》2004,60(52):12201-12209
Stemmosides C and D, two novel pregnane glycosides characterized by an unusual C-17 side chain were isolated from the pericarps of Solenostemma argel. In addition, stemmoside D displays an uncommon 14β proton configuration, apparently being the first pregnane isolated from plants known to have a 15 keto, cis CD ring junction. Their structures have been established by ESIMS and NMR experiments. The relative configuration of the molecules was determined using a strategy based on the simulation of 1H, 13C, and J coupling NMR parameters. DFT calculations of 1H and 13C chemical shifts, and of the 1H homonuclear spin–spin coupling constants were performed with the mPW1PW91 functional using the 6-31G(d,p) basis set on the fully optimized geometries of all the possible stereoisomers. 相似文献
58.
A. Baeza M. Fernández M. Herranz F. Legarda C. Miró A. Salas 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(2):321-326
We studied the effectiveness of potable water treatment processes that consist of the stages of coagulation-flocculation-decantation,
using iron-based coagulants, in eliminating gamma-emitting man-made radioisotopes of cesium, strontium, and americium from
two natural waters with different degrees of mineralization. The resulting decontamination was found to depend on the chemical
behavior of each of the radionuclides considered, on the pH at which the process of coagulation is carried out, and on the
concentration of the other stable cations present.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
59.
Alberto Mariani Simone Bidali Stefano Fiori Marco Sangermano Giulio Malucelli Roberta Bongiovanni Aldo Priola 《Journal of polymer science. Part A, Polymer chemistry》2004,42(9):2066-2072
By combining frontal polymerization and radical‐induced cationic polymerization, it was possible to cure thick samples of an epoxy monomer bleached by UV light. The effect of the relative amounts of cationic photoinitiator and radical initiator was thoroughly investigated and was related to the front's velocity and its maximum temperature. The materials obtained were characterized by quantitative conversion also in the deeper layers, not reached by UV light. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2066–2072, 2004 相似文献
60.
Michael A. Brook Yang Chen Kui Guo Zheng Zhang Wen Jin Anil Deisingh Jorge Cruz-Aguado John D. Brennan 《Journal of Sol-Gel Science and Technology》2004,31(1-3):343-348
The preparation of discrete polyol based silane precursors derived from glycerol by a simple one-pot process is described. These polyol-based silanes could be hydrolyzed under mild pH conditions and upon gelation resulted in the formation of optically clear, monolithic, mesoporous silica. The hydrolysis and condensation reactions lead to cure rates that are very sensitive to ionic strength, but are almost unaffected by pH in contrast to those of alkoxysilanes derived from primary alcohols such as Si(OEt)4. Residual glycerol in the silica monolith could be removed by washing, or could be left in the silica to reduce the magnitude of shrinkage during long term storage. The biocompatible glyceroxysilane precursors lead to materials that were able to retain the activity of entrapped enzymes over repeated cycles of use for periods of up to several months. 相似文献