全文获取类型
收费全文 | 11818篇 |
免费 | 282篇 |
国内免费 | 95篇 |
专业分类
化学 | 8226篇 |
晶体学 | 225篇 |
力学 | 253篇 |
综合类 | 1篇 |
数学 | 2024篇 |
物理学 | 1466篇 |
出版年
2022年 | 84篇 |
2021年 | 105篇 |
2020年 | 126篇 |
2019年 | 118篇 |
2018年 | 93篇 |
2017年 | 96篇 |
2016年 | 227篇 |
2015年 | 194篇 |
2014年 | 201篇 |
2013年 | 574篇 |
2012年 | 541篇 |
2011年 | 637篇 |
2010年 | 321篇 |
2009年 | 279篇 |
2008年 | 588篇 |
2007年 | 618篇 |
2006年 | 597篇 |
2005年 | 559篇 |
2004年 | 490篇 |
2003年 | 388篇 |
2002年 | 457篇 |
2001年 | 130篇 |
2000年 | 139篇 |
1999年 | 134篇 |
1998年 | 126篇 |
1997年 | 156篇 |
1996年 | 203篇 |
1995年 | 134篇 |
1994年 | 123篇 |
1993年 | 132篇 |
1992年 | 133篇 |
1991年 | 115篇 |
1990年 | 132篇 |
1989年 | 116篇 |
1988年 | 119篇 |
1987年 | 101篇 |
1986年 | 106篇 |
1985年 | 184篇 |
1984年 | 206篇 |
1983年 | 143篇 |
1982年 | 230篇 |
1981年 | 197篇 |
1980年 | 169篇 |
1979年 | 154篇 |
1978年 | 148篇 |
1977年 | 134篇 |
1976年 | 145篇 |
1975年 | 127篇 |
1974年 | 153篇 |
1973年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
This paper explores the structure of optimal investment strategies using stochastic programming and duality theory in investment
portfolios containing options for a hedge fund manager who attempts to beat a benchmark. Explicit optimal conditions for option
investments are obtained for several models.
This research was supported by Inquire, the Social Sciences and Humanities Research Council of Canada, the Natural Sciences
and Engineering Research Council of Canada, the National Center of Competence in Research FINRISK, a research instrument of
the Swiss National Science Foundation, and MIT’s Sloan School of Management.
J. R. Rodríguez-Mancilla thanks Gabriel Casillas-Olvera, Deputy Manager of Risk Control at Banco de Mexico, who read several
drafts of this paper and made many helpful comments. The opinions in this paper do not necessarily represent those of Banco
de México. 相似文献
997.
William R. Dolbier Jr. Yian Zhai Wei Xu Will Wheelus Florian Dulong Efram Goldberg Ion Ghiviriga Merle A. Battiste 《Journal of fluorine chemistry》2008,129(12):1133-1138
When 4-nitro-AF4 is treated with nucleophiles such as alkoxides and cyanide, a novel ring opening, cyclophane destroying reaction is observed whereby, via an SNAr mechanism, the nucleophile attacks the bridgehead aryl carbon vicinal to the nitro group with subsequent aryl-CF2 bond cleavage. 相似文献
998.
William Layton Carolina C. Manica Monika Neda Leo G. Rebholz 《Numerical Methods for Partial Differential Equations》2008,24(2):555-582
We study a computationally attractive algorithm (based on an extrapolated Crank‐Nicolson method) for a recently proposed family of high accuracy turbulence models, the Leray‐deconvolution family. First we prove convergence of the algorithm to the solution of the Navier‐Stokes equations and delineate its (optimal) accuracy. Numerical experiments are presented which confirm the convergence theory. Our 3d experiments also give a careful comparison of various related approaches. They show the combination of the Leray‐deconvolution regularization with the extrapolated Crank‐Nicolson method can be more accurate at higher Reynolds number that the classical extrapolated trapezoidal method of Baker (Report, Harvard University, 1976). We also show the higher order Leray‐deconvolution models (e.g. N = 1,2,3) have greater accuracy than the N = 0 case of the Leray‐α model. Numerical experiments for the 2d step problem are also successfully investigated. Around the critical Reynolds number, the low order models inhibit vortex shedding behind the step. The higher order models, correctly, do not. To estimate the complexity of using Leray‐deconvolution models for turbulent flow simulations we estimate the models' microscale.© 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008 相似文献
999.
John David Norris James David Joseph Andrea Barreto Sherk Dalia Juzumiene Philip Stewart Turnbull Stephen William Rafferty Huaxia Cui Erin Anderson Daju Fan Delita Arnelle Dye Xiang Deng Dmitri Kazmin Ching-Yi Chang Timothy Mark Willson Donald Patrick McDonnell 《Chemistry & biology》2009,16(4):452-460
1000.