全文获取类型
收费全文 | 583225篇 |
免费 | 4828篇 |
国内免费 | 1305篇 |
专业分类
化学 | 284282篇 |
晶体学 | 7017篇 |
力学 | 30820篇 |
综合类 | 17篇 |
数学 | 85497篇 |
物理学 | 181725篇 |
出版年
2021年 | 5018篇 |
2020年 | 5501篇 |
2019年 | 6255篇 |
2018年 | 13056篇 |
2017年 | 13453篇 |
2016年 | 13946篇 |
2015年 | 6625篇 |
2014年 | 10571篇 |
2013年 | 23687篇 |
2012年 | 21013篇 |
2011年 | 29271篇 |
2010年 | 20644篇 |
2009年 | 20659篇 |
2008年 | 26935篇 |
2007年 | 29022篇 |
2006年 | 18875篇 |
2005年 | 20186篇 |
2004年 | 17307篇 |
2003年 | 16184篇 |
2002年 | 14904篇 |
2001年 | 14882篇 |
2000年 | 11634篇 |
1999年 | 8811篇 |
1998年 | 7649篇 |
1997年 | 7404篇 |
1996年 | 6621篇 |
1995年 | 6239篇 |
1994年 | 6265篇 |
1993年 | 6002篇 |
1992年 | 6348篇 |
1991年 | 6854篇 |
1990年 | 6550篇 |
1989年 | 6456篇 |
1988年 | 6313篇 |
1987年 | 6143篇 |
1986年 | 5863篇 |
1985年 | 7437篇 |
1984年 | 7834篇 |
1983年 | 6572篇 |
1982年 | 6860篇 |
1981年 | 6367篇 |
1980年 | 6026篇 |
1979年 | 6570篇 |
1978年 | 6811篇 |
1977年 | 6658篇 |
1976年 | 6635篇 |
1975年 | 6316篇 |
1974年 | 6143篇 |
1973年 | 6516篇 |
1972年 | 4720篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
M. D. Srinivas 《Pramana》2003,60(6):1137-1152
We derive an optimal bound on the sum of entropic uncertainties of two or more observables when they are sequentially measured
on the same ensemble of systems. This optimal bound is shown to be greater than or equal to the bounds derived in the literature
on the sum of entropie uncertainties of two observables which are measured on distinct but identically prepared ensembles
of systems. In the case of a two-dimensional Hilbert space, the optimum bound for successive measurements of two-spin components,
is seen to be strictly greater than the optimal bound for the case when they are measured on distinct ensembles, except when
the spin components are mutually parallel or perpendicular 相似文献
992.
H. E. Schweyer R. N. Traxler und L. A. H. Baum 《Fresenius' Journal of Analytical Chemistry》1940,119(1-2):58
Ohne Zusammenfassung 相似文献
993.
994.
995.
F. A. Flückiger 《Fresenius' Journal of Analytical Chemistry》1870,9(1):337-342
Ohne Zusammenfassung 相似文献
996.
Keller Teichmann Hans Pfeiffer W. Langenbeck A. Reid Heinrich Menzel Th. Höpner W. Mühlsteph M. Ulmann Geib R. E. Liesegang 《Colloid and polymer science》1939,87(1):100-104
Ohne Zusammenfassung 相似文献
997.
On the Application of the Auxiliary Problem Principle 总被引:6,自引:0,他引:6
The auxiliary problem principle (APP) derives from a general theory on decomposition-coordination methods establishing a comprehensive framework for both one-level and two-level methods. In this paper, the results of the two-level methods of APP are specialized for an efficient application to some engineering problems. 相似文献
998.
999.
For the decay of two identical particles with close momenta, the angular correlations between the directions of emission of decay products are considered on the basis of the model of independent single-particle sources emitting unstable unpolarized particles of nonzero spin. These correlations reflect spin correlations that are caused by quantum-statistics and final-state-interaction effects. A general theory of angular correlations in the decays of two arbitrarily polarized particles (resonances) is constructed. 相似文献
1000.
A T Brint 《The Journal of the Operational Research Society》2003,54(11):1177-1188
The annual turnover of online auctions is already in tens of billions of dollars and this amount is predicted to grow substantially over the next few years. Hence, it is important to know how buyers and sellers can influence their chances of success. Therefore, data were collected from eBay auctions for three different categories of collectible items, namely those with a published guide price, those with a rough guide price and those having no easily obtainable guide price. The options available to buyers and sellers of items were then analysed. It was found that it was hard for the seller to influence an item's achieved price significantly, apart from items with no guide price where the starting price could have an effect. Most bidders bid close to the current value and so there were insufficient data to determine the consequences of timing on the placing of high bids. For low bids, delaying a bid was found to improve significantly the chances of winning for one of the data sets. 相似文献