全文获取类型
收费全文 | 7180篇 |
免费 | 216篇 |
国内免费 | 14篇 |
专业分类
化学 | 5437篇 |
晶体学 | 81篇 |
力学 | 70篇 |
综合类 | 2篇 |
数学 | 323篇 |
物理学 | 1497篇 |
出版年
2023年 | 50篇 |
2022年 | 59篇 |
2021年 | 74篇 |
2020年 | 128篇 |
2019年 | 121篇 |
2018年 | 70篇 |
2017年 | 36篇 |
2016年 | 138篇 |
2015年 | 156篇 |
2014年 | 156篇 |
2013年 | 348篇 |
2012年 | 372篇 |
2011年 | 400篇 |
2010年 | 232篇 |
2009年 | 229篇 |
2008年 | 398篇 |
2007年 | 426篇 |
2006年 | 402篇 |
2005年 | 413篇 |
2004年 | 366篇 |
2003年 | 300篇 |
2002年 | 304篇 |
2001年 | 152篇 |
2000年 | 150篇 |
1999年 | 116篇 |
1998年 | 87篇 |
1997年 | 77篇 |
1996年 | 99篇 |
1995年 | 76篇 |
1994年 | 67篇 |
1993年 | 81篇 |
1992年 | 80篇 |
1991年 | 78篇 |
1990年 | 58篇 |
1989年 | 71篇 |
1988年 | 62篇 |
1987年 | 68篇 |
1986年 | 54篇 |
1985年 | 112篇 |
1984年 | 87篇 |
1983年 | 49篇 |
1982年 | 69篇 |
1981年 | 67篇 |
1980年 | 69篇 |
1979年 | 68篇 |
1978年 | 52篇 |
1977年 | 43篇 |
1976年 | 47篇 |
1974年 | 33篇 |
1973年 | 31篇 |
排序方式: 共有7410条查询结果,搜索用时 8 毫秒
21.
We first note that Gentzen's proof-reduction for his consistency proof of PA can be directly interpreted as moves of Kirby-Paris' Hydra Game, which implies a direct independence proof of the game (Section 1 and Appendix). Buchholz's Hydra Game for labeled hydras is known to be much stronger than PA. However, we show that the one-dimensional version of Buchholz's Game can be exactly identified to Kirby-Paris' Game (which is two-dimensional but without labels), by a simple and natural interpretation (Section 2). Jervell proposed another type of a combinatorial game, by abstracting Gentzen's proof-reductions and showed that his game is independent of PA. We show (Section 3) that this Jervell's game is actually much stronger than PA, by showing that the critical ordinal of Jervell's game is φω (0) (while that of PA or of Kirby-Paris' Game is φ1 (0) = ?0) in the Veblen hierarchy of ordinals. 相似文献
22.
Masahiro Kubo 《Journal of Mathematical Analysis and Applications》2005,307(1):232-244
We study Neumann problem for a class of nonlinear degenerate parabolic PDE. A typical nonlinearity we have in mind is, for instance, β(u)=−1/u(u>0). We establish a necessary and sufficient condition on given data for existence of solution. 相似文献
23.
Hiroshi Sato 《Journal of Theoretical Probability》1992,5(2):349-353
The aim of this paper is to characterize the nuclearity of an integral operator, defined by a continuous non-negative definite square integrable kernel on a separable metric space, in terms of the integrability of the trace of the kernel function. Nuclearity here plays a role forU-statistics. 相似文献
24.
25.
Toshiyuki Oyama Akira Kitamura Eiichi Sato Masao Tomoi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2694-2706
The factors affecting pattern‐forming properties in reaction development patterning were examined with polyarylates with various bisphenol moieties. The developability of the photosensitive polyarylates was dependent on the properties of the subtituent (R) in the bisphenol moieties. The development time decreased in the following order: R?C(CH3)2 > fluorenyl unit ? phenolphthalein unit > C(CF3)2 > SO2. This order agreed with that of the reactivity between the polyarylates and ethanolamine, and these orders can be explained by pKa of the bisphenol used to prepare the polyarylates. The development with NH2? R′? OH resulted in successful positive‐tone pattern formation. However, pattern formation with the developers containing NH2? R′? OCH3 was unsuccessful. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2694–2706, 2006 相似文献
26.
In this study, we attempted to control the timing of light-emission from bioluminescent bacteria, by changed cell numbers inoculated into medium. Luminous bacteria express bioluminescence when the number of cells reached a threshold. Inoculated cell density had an effect on the time of bioluminescence starting. Samples were prepared by varying cell density of inoculation. In the results, all the vials showed different luminescence profiles in the order of inoculated cell population. 相似文献
27.
Masahiro Nakao Chikako Yamazaki Hiroshi Tominaga Takako Yamaguchi Yoshikazu Fujita 《Analytical sciences》2006,22(2):313-316
A simple and highly sensitive spectrophotometric method for the determination of anthracycline anticancer agents, such as Daunorubicin hydrochloride (DAU), was established by using aluminum(III) and Chromazurol S (CAS) in a nonionic surfactant micellar medium. In the case of determination of DAU, the apparent molar absorptivity was 1.3 x 10(5) dm3 mol(-1) cm(-1) at 615 nm. Beer's law was obeyed in the concentration range of 0.028 - 2.82 microg ml(-1) for DAU. Owing to no need for solvent extraction, this method could be applied to assays of DAU and related drugs in pharmaceutical preparations. 相似文献
28.
29.
30.
Bond IA Budding E Conway MJ Fenton KB Fujii H Fujii Z Fujimoto M Hasegawa H Hayashida N Honda M Hotta N Humble JE Kabe S Kasahara K Kifune T Masaike A Matsubara Y Mitsui K Miura Y Mori M Murakami K Muraki Y Nagano M Nakamura K Nakamura T Norris PM Ohashi Y Okada A Saito T Sakata M Sato H Shibata S Shima M Storey JR Tanimori T Teshima M Torii S Uchino K Watase Y Woodhams MD Yamamoto Y Yock PC Yuda T 《Physical review letters》1988,61(20):2292-2295