全文获取类型
收费全文 | 9133篇 |
免费 | 273篇 |
国内免费 | 78篇 |
专业分类
化学 | 6665篇 |
晶体学 | 42篇 |
力学 | 206篇 |
数学 | 1362篇 |
物理学 | 1209篇 |
出版年
2023年 | 35篇 |
2022年 | 67篇 |
2021年 | 110篇 |
2020年 | 145篇 |
2019年 | 141篇 |
2018年 | 101篇 |
2017年 | 74篇 |
2016年 | 220篇 |
2015年 | 191篇 |
2014年 | 223篇 |
2013年 | 517篇 |
2012年 | 540篇 |
2011年 | 683篇 |
2010年 | 307篇 |
2009年 | 237篇 |
2008年 | 522篇 |
2007年 | 600篇 |
2006年 | 626篇 |
2005年 | 503篇 |
2004年 | 460篇 |
2003年 | 393篇 |
2002年 | 365篇 |
2001年 | 134篇 |
2000年 | 88篇 |
1999年 | 84篇 |
1998年 | 80篇 |
1997年 | 108篇 |
1996年 | 113篇 |
1995年 | 84篇 |
1994年 | 76篇 |
1993年 | 90篇 |
1992年 | 73篇 |
1991年 | 56篇 |
1990年 | 83篇 |
1989年 | 44篇 |
1988年 | 61篇 |
1987年 | 60篇 |
1986年 | 74篇 |
1985年 | 109篇 |
1984年 | 105篇 |
1983年 | 68篇 |
1982年 | 95篇 |
1981年 | 93篇 |
1980年 | 94篇 |
1979年 | 69篇 |
1978年 | 85篇 |
1977年 | 62篇 |
1976年 | 58篇 |
1975年 | 52篇 |
1973年 | 59篇 |
排序方式: 共有9484条查询结果,搜索用时 15 毫秒
161.
162.
163.
164.
165.
Stephen L. Adler 《Foundations of Physics》2018,48(11):1557-1567
We review the argument that latent image formation is a measurement in which the state vector collapses, requiring an enhanced noise parameter in objective reduction models. Tentative observation of a residual noise at this level, plus several experimental bounds, imply that the noise must be colored (i.e., non-white), and hence frame dependent and non-relativistic. Thus a relativistic objective reduction model, even if achievable in principle, would be incompatible with experiment; the best one can do is the non-relativistic CSL model. This negative conclusion has a positive aspect, in that the non-relativistic CSL reduction model evades the argument leading to the Conway–Kochen “Free Will Theorem”. 相似文献
166.
Matrix reactions of Mg, Zn and Cd atoms and NO2 have been performed. Infrared absorptions in the 1220 cm?1 range show isotopic shifts appropriate for M+NO2? species. Bands near 950 cm?1 in the zinc experiments are attributed to a different ion-pair structural isomer. 相似文献
167.
Payne Stephen A. Chase L. L. Smith L. K. Chai Bruce H. T. 《Optical and Quantum Electronics》1990,22(1):S259-S268
The results of flashlamp pumping of the LiCaAIF6:Cr3+ (Cr:LiCAF) laser crystal are reported. We have so far obtained slope efficiencies as high as 1.55% in a close-coupled, diffusely reflecting cavity. Based on the measured insertion loss of the presently available material, we predict that an efficiency of about 4% will be obtained when low-loss material becomes available. This extrapolated efficiency is comparable with the performance of a high-quality alexandrite laser rod in the same apparatus. 相似文献
168.
Rebekah Hahn Stephen Mitchell 《Transactions of the American Mathematical Society》2007,359(11):5207-5238
The Iwasawa algebra is a power series ring in one variable over the -adic integers. It has long been studied by number theorists in the context of -extensions of number fields. It also arises, however, as a ring of operations in -adic topological -theory. In this paper we study -local stable homotopy theory using the structure theory of modules over the Iwasawa algebra. In particular, for odd we classify -local spectra up to pseudo-equivalence (the analogue of pseudo-isomorphism for -modules) and give an Iwasawa-theoretic classification of the thick subcategories of the weakly dualizable spectra.
169.
170.
We investigate the quality of solutions obtained from sample-average approximations to two-stage stochastic linear programs
with recourse. We use a recently developed software tool executing on a computational grid to solve many large instances of
these problems, allowing us to obtain high-quality solutions and to verify optimality and near-optimality of the computed
solutions in various ways.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grant 9726385.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grant DMS-0073770.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grants 9726385 and 0082065. 相似文献