全文获取类型
收费全文 | 18972篇 |
免费 | 859篇 |
国内免费 | 99篇 |
专业分类
化学 | 13074篇 |
晶体学 | 121篇 |
力学 | 420篇 |
数学 | 2894篇 |
物理学 | 3421篇 |
出版年
2023年 | 122篇 |
2022年 | 172篇 |
2021年 | 268篇 |
2020年 | 377篇 |
2019年 | 397篇 |
2018年 | 234篇 |
2017年 | 236篇 |
2016年 | 601篇 |
2015年 | 557篇 |
2014年 | 644篇 |
2013年 | 1027篇 |
2012年 | 1116篇 |
2011年 | 1248篇 |
2010年 | 745篇 |
2009年 | 659篇 |
2008年 | 1036篇 |
2007年 | 1024篇 |
2006年 | 952篇 |
2005年 | 881篇 |
2004年 | 773篇 |
2003年 | 638篇 |
2002年 | 605篇 |
2001年 | 308篇 |
2000年 | 290篇 |
1999年 | 273篇 |
1998年 | 241篇 |
1997年 | 231篇 |
1996年 | 264篇 |
1995年 | 247篇 |
1994年 | 217篇 |
1993年 | 211篇 |
1992年 | 199篇 |
1991年 | 174篇 |
1990年 | 174篇 |
1989年 | 174篇 |
1988年 | 149篇 |
1987年 | 126篇 |
1986年 | 114篇 |
1985年 | 166篇 |
1984年 | 161篇 |
1983年 | 126篇 |
1982年 | 153篇 |
1981年 | 157篇 |
1980年 | 132篇 |
1979年 | 140篇 |
1978年 | 158篇 |
1977年 | 115篇 |
1976年 | 100篇 |
1975年 | 117篇 |
1974年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Anjos JC Appel JA Bean A Bracker SB Browder TE Cremaldi LM Duboscq JE Elliott JR Escobar CO Gibney MC Hartner GF Karchin PE Kumar BR Losty MJ Luste GJ Mantsch PM Martin JF McHugh S Menary SR Morrison RJ Nash T Ong P Pinfold J Punkar G Purohit MV Santoro AF Sidhu JS Sliwa K Sokoloff MD Souza MH Spalding WJ Streetman ME Stundia AB Witherell MS 《Physical review letters》1990,64(24):2885-2888
122.
123.
Martin Schlichenmaier 《Letters in Mathematical Physics》1990,19(2):151-165
Krichever-Novikov algebras of meromorphic vector fields with more than two poles on higher genus Riemann surfaces are introduced. The structure of these algebras and their induced modules of forms of weight is studied. 相似文献
124.
125.
126.
Stewart C Zieminski A Blessing S Crittenden R Draper P Dzierba A Heinz R Krider J Marshall T Martin J Sambamurti A Smith P Sulanke T Gomez R Dauwe L Haggerty H Malamud E Nikolic M Hagopian S Abrams R Ares J Goldberg H Halliwell C Margulies S McLeod D Salminen A Solomon J Wu G Ellsworth R Goodman J Gupta S Yodh G Watts T Abramov V Antipov Y Baldin B Denisov S Glebov V Gorin Y Kryshkin V Petrukhin A Polovnikov S Sulyaev R 《Physical review D: Particles and fields》1990,42(5):1385-1395
127.
Summary Consider a reversible Markov chain X
n
which takes values in a subset of d. If the steps of the chain are uniformly bounded and the invariant measure satisfies a mild regularity condition, Varopoulos, Carne and Kesten have obtained estimates on
\lambda n^{1/2} )$$
" align="middle" border="0">
which exhibit a Gaussian tail in but blow up as n. Following Kesten's approach we derive bounds which are uniform in n in some special cases. Our main result, however, is an example which shows that in general the estimates of Varopoulos, Carne and Kesten are essentially best possible.Research partially supported by an S.E.R.C. (U.K.) visiting fellowship and an operating grant from N.S.E.R.C. of Canada 相似文献
128.
A variety of dolphin sonar discrimination experiments have been conducted, yet little is known about the cues utilized by dolphins in making fine target discriminations. In order to gain insights on cues available to echolocating dolphins, sonar discrimination experiments were conducted with human subjects using the same targets employed in dolphin experiments. When digital recordings of echoes from targets ensonified with a dolphinlike signal were played back at a slower rate to human subjects, they could also make fine target discriminations under controlled laboratory conditions about as well as dolphins under less controlled conditions. Subjects reported that time-separation-pitch and duration cues were important. They also reported that low-amplitude echo components 32 dB below the maximum echo component were usable. The signal-to-noise ratio had to be greater than 10 dB above the detection threshold for simple discrimination and 30 dB for difficult discrimination. Except for two cases in which spectral cues in the form of "click pitch" were important, subjects indicated that time-domain rather than frequency-domain processing seemed to be more relevant in analyzing the echoes. 相似文献
129.
Let G be a Lie transformation group on a manifold M. Then a map f: NG is differentiable, iff for every point pM the map q f(q)·p is differentiable. 相似文献
130.