全文获取类型
收费全文 | 113222篇 |
免费 | 6041篇 |
国内免费 | 4003篇 |
专业分类
化学 | 49030篇 |
晶体学 | 1126篇 |
力学 | 8770篇 |
综合类 | 242篇 |
数学 | 35862篇 |
物理学 | 28236篇 |
出版年
2024年 | 112篇 |
2023年 | 764篇 |
2022年 | 1235篇 |
2021年 | 1348篇 |
2020年 | 1449篇 |
2019年 | 1333篇 |
2018年 | 11301篇 |
2017年 | 11068篇 |
2016年 | 7516篇 |
2015年 | 2451篇 |
2014年 | 2288篇 |
2013年 | 2875篇 |
2012年 | 6946篇 |
2011年 | 13436篇 |
2010年 | 7668篇 |
2009年 | 7965篇 |
2008年 | 8678篇 |
2007年 | 10582篇 |
2006年 | 2042篇 |
2005年 | 2813篇 |
2004年 | 2785篇 |
2003年 | 2927篇 |
2002年 | 1883篇 |
2001年 | 978篇 |
2000年 | 975篇 |
1999年 | 989篇 |
1998年 | 882篇 |
1997年 | 782篇 |
1996年 | 902篇 |
1995年 | 717篇 |
1994年 | 628篇 |
1993年 | 565篇 |
1992年 | 502篇 |
1991年 | 426篇 |
1990年 | 373篇 |
1989年 | 294篇 |
1988年 | 274篇 |
1987年 | 255篇 |
1986年 | 198篇 |
1985年 | 202篇 |
1984年 | 177篇 |
1983年 | 152篇 |
1982年 | 121篇 |
1981年 | 97篇 |
1980年 | 95篇 |
1979年 | 77篇 |
1978年 | 60篇 |
1976年 | 43篇 |
1975年 | 47篇 |
1914年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The Hamiltonian formulation of the usual complex quantum mechanics in the theory of generalized quantum dynamics is discussed.
After the total trace Lagrangian, total trace Hamiltonian and two kinds of Poisson brackets are introduced, both the equations
of motion of some total trace functionals which are expressed by total trace Poisson brackets and the equations of motion
of some operators which are expressed by the without-total-trace Poisson brackets are obtained. Then a set of basic equations
of motion of the usual complex quantum mechanics are obtained, which are also expressed by the Poisson brackets and total
trace Hamiltonian in the generalized quantum dynamics. The set of equations of motion are consistent with the corresponding
Heisenberg equations.
Project supported by Prof. T.D. Lee’s NNSC Grant, the National Natural Science Foundation of China, the Foundation of Ph.
D. Directing Programme of Chinese University, and the Chinese Academy of Sciences. 相似文献
992.
993.
994.
995.
Brick DH Widgoff M Beilliere P Lutz P Narjoux JL Gelfand N Alyea ED Bloomer M Bober J Busza W Cole B Frank TA Fuess TA Grodzins L Hafen ES Haridas P Huang D Huang HZ Hulsizer R Kistiakowsky V Ledoux RJ Milstene C Noguchi S Oh SH Pless IA Steadman S Stoughton TB Suchorebrow V Tether S Trepagnier PC Wadsworth BF Wu Y Yamamoto RK Cohn HO Calligarich E Castoldi C Dolfini R Introzzi G Ratti S Badiak M DiMarco R Jacques PF Kalelkar M Plano RJ Stamer PE Brucker EB Koller EL Alexander G Grunhaus J 《Physical review D: Particles and fields》1990,41(3):765-773
996.
This paper is concerned with a combined production-transportation scheduling problem. The problem comprises a simple, two-machine, automated manufacturing cell, which either stands alone or is a subunit of a complete flexible manufacturing system. The cell consists of two machines in series with a dedicated part-handling device such as a crane or robotic arm for transferring parts from the first machine to the second. The loading of a new piece on the first machine and the ejection of a finished piece from the second machine are performed by dedicated automated mechanisms. The introduction of parts into the system is done n at a time, whereby the parts are reshuffled into a sequence that minimizes completion time. All processing and transfer times are considered deterministic—a reasonable assumption for a cell comprising a robotic transfer device and two CNC machining units. What complicates the problem is the assumption of a non-negligible time for the transfer device to return (empty) from the second machine to the first. The operation is a generalization of a two-machine flowshop problem, and is formulated as a specially structured, asymmetric travelling salesman problem. An approximate polynomial time 0(n log n) algorithm is proffered. The procedure incorporates a lower bound using the Gilmore–Gomory algorithm for the no-wait, two-machine flowshop problem. 相似文献
997.
998.
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
999.
Wu DY Hayes K Perl ML Barklow T Boyarski A Burchat PR Burke DL Dorfan JM Feldman GJ Gladney L Hanson G Hollebeek RJ Innes WR Jaros JA Karlen D Klein SR Lankford AJ Larsen RR LeClaire BW Lockyer NS Lüth V Ong RA Richter B Riles K Yelton JM Abrams G Amidei D Baden AR Boyer J Butler F Gidal G Gold MS Goldhaber G Golding L Haggerty J Herrup D Juricic I Kadyk JA Levi ME Nelson ME Rowson PC Schellman H Schmidke WB Sheldon PD Trilling GH Wood DR Schaad T 《Physical review D: Particles and fields》1990,41(7):2339-2342
1000.
Wu Zhende 《数学学报(英文版)》1989,5(4):302-306
In this paper, we determine the groups
(k
i
are odd),
(k
i
are odd and
(k
i
are even andn>k
l
),
(k
i
are even andn>k
l
),
(k
i
are even andn>k
l
,k
l
12),J
n
1,2,J
n
2,3,J
n
1,4. And we obtain the relation Im
n
k
=J
n
l,k
. 相似文献