全文获取类型
收费全文 | 643738篇 |
免费 | 5018篇 |
国内免费 | 1570篇 |
专业分类
化学 | 287409篇 |
晶体学 | 9258篇 |
力学 | 38211篇 |
综合类 | 10篇 |
数学 | 115227篇 |
物理学 | 200211篇 |
出版年
2021年 | 5094篇 |
2020年 | 5458篇 |
2019年 | 6380篇 |
2018年 | 21124篇 |
2017年 | 21245篇 |
2016年 | 19022篇 |
2015年 | 7494篇 |
2014年 | 11805篇 |
2013年 | 24536篇 |
2012年 | 24044篇 |
2011年 | 36512篇 |
2010年 | 25228篇 |
2009年 | 25992篇 |
2008年 | 31246篇 |
2007年 | 34364篇 |
2006年 | 19277篇 |
2005年 | 20280篇 |
2004年 | 18199篇 |
2003年 | 17476篇 |
2002年 | 15868篇 |
2001年 | 15902篇 |
2000年 | 12401篇 |
1999年 | 9302篇 |
1998年 | 8203篇 |
1997年 | 7847篇 |
1996年 | 7449篇 |
1995年 | 6513篇 |
1994年 | 6446篇 |
1993年 | 6335篇 |
1992年 | 6627篇 |
1991年 | 7170篇 |
1990年 | 6892篇 |
1989年 | 6828篇 |
1988年 | 6457篇 |
1987年 | 6643篇 |
1986年 | 6201篇 |
1985年 | 7526篇 |
1984年 | 7810篇 |
1983年 | 6599篇 |
1982年 | 6761篇 |
1981年 | 6333篇 |
1980年 | 6131篇 |
1979年 | 6761篇 |
1978年 | 6805篇 |
1977年 | 6860篇 |
1976年 | 6897篇 |
1975年 | 6447篇 |
1974年 | 6252篇 |
1973年 | 6471篇 |
1972年 | 5039篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
S. Cloëz 《Fresenius' Journal of Analytical Chemistry》1872,11(1):71
Ohne Zusammenfassung 相似文献
942.
943.
Ohne Zusammenfassung 相似文献
944.
S. B. Ellis S. J. Kiehl W. S. Hughes K. Schwabe W. C. Gardiner H. L. Sanders H. Yoshimura Hanna Jablezynska-Jedrzewska J. Domański W. A. Dorfman P. Nylén Barbara Stone F. Hovorka W. C. Dearing E. Biilmann W. Kordatzki P. Wulff G. Florence A. Drilhon P. Szigeti O. Tomiček F. Poupě O. Redlich W. Stricks 《Analytical and bioanalytical chemistry》1937,111(2-4):94-104
945.
J. B. Lewis E. L. Baldeschwieler L. D. Tabern E. F. Shelberg D. Hillis S. Cromer I. F. Bingham S. Givaudon M. Aubert M. R. Moutte A. Andant P. Lambert J. Lecomte J. Tausz H. Wolf B. Gordon W. Dachnow I. Perrier M. Lobunetz M. O. Chaikin C. Engler D. Holde 《Analytical and bioanalytical chemistry》1940,119(7-8):307-310
946.
947.
948.
A new family of annulated inositols (inosito-inositols) has been conceptualized. Naphthalene has been elaborated into novel cyclohexa-annulated neo- and chiro-inositols, with two additional hydroxyl functionalities, through a series of stereoselective oxyfunctionalization protocols. The trans-ring fusion present in these new annulated inositols ensures conformational locking. 相似文献
949.
We present all-atom molecular dynamics simulations ofn-hexane on the basal plane of graphite at monolayer and multilayer coverages. In keeping with experimental data, we find the
presence of ordered adsorbed layers both at single monolayer coverage and when the adsorbed layer coexists with excess liquid
adsorbate. Using a simulation method that does not impose any particular periodicity on the adsorbed layer, we quantitatively
compare our results to the results of neutron diffraction experiments and find a structural transition from a uniaxially incommensurate
lattice to a fully commensurate structure on increasing the coverage from a monolayer to a multilayer. The zig-zag backbone
planes of all the alkane molecules lie parallel to the graphite surface at the multilayer coverage, while a few molecules
are observed to attain the perpendicular orientation at monolayer coverage.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
950.
Chris Hope 《The Journal of the Operational Research Society》2003,54(11):1167-1176
What strategy should a football (soccer, in American parlance) club adopt when deciding whether to sack its manager? This paper introduces a simple model assuming that a club's objective is to maximize the number of league points that it scores per season. The club's strategy consists of three choices: the length of the honeymoon period during which it will not consider sacking a new manager, the level of the performance trapdoor below which the manager get the sack, and the weight that it will give to more recent games compared to earlier ones. Some data from the last six seasons of the English Premiership are used to calibrate the model. At this early stage of the research, the best strategy appears to have only a short honeymoon period of eight games (much less than the actual shortest period of 12 games), to set the trapdoor at 0.74 points per game, and to put 47% of the weight on the last five games. A club adopting this strategy would obtain on average 56.8 points per season, compared to a Premiership average of 51.8 points. 相似文献