全文获取类型
收费全文 | 319952篇 |
免费 | 4424篇 |
国内免费 | 737篇 |
专业分类
化学 | 175588篇 |
晶体学 | 4423篇 |
力学 | 13489篇 |
综合类 | 11篇 |
数学 | 39140篇 |
物理学 | 92462篇 |
出版年
2020年 | 2876篇 |
2019年 | 3096篇 |
2018年 | 4552篇 |
2017年 | 4187篇 |
2016年 | 6179篇 |
2015年 | 4148篇 |
2014年 | 5821篇 |
2013年 | 13808篇 |
2012年 | 11568篇 |
2011年 | 13604篇 |
2010年 | 9300篇 |
2009年 | 8793篇 |
2008年 | 12489篇 |
2007年 | 12624篇 |
2006年 | 11643篇 |
2005年 | 10730篇 |
2004年 | 9675篇 |
2003年 | 8605篇 |
2002年 | 8263篇 |
2001年 | 8187篇 |
2000年 | 6466篇 |
1999年 | 4945篇 |
1998年 | 4295篇 |
1997年 | 4272篇 |
1996年 | 4116篇 |
1995年 | 3671篇 |
1994年 | 3871篇 |
1993年 | 3577篇 |
1992年 | 4065篇 |
1991年 | 4007篇 |
1990年 | 3941篇 |
1989年 | 3761篇 |
1988年 | 3815篇 |
1987年 | 3706篇 |
1986年 | 3499篇 |
1985年 | 4733篇 |
1984年 | 4979篇 |
1983年 | 4108篇 |
1982年 | 4331篇 |
1981年 | 4230篇 |
1980年 | 4177篇 |
1979年 | 4144篇 |
1978年 | 4456篇 |
1977年 | 4325篇 |
1976年 | 4420篇 |
1975年 | 4071篇 |
1974年 | 4107篇 |
1973年 | 4265篇 |
1972年 | 2947篇 |
1971年 | 2453篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Applied Magnetic Resonance - The suggested approach allowed us to derive analytical expressions for modeling the shape of solid-echo signal and its time evolution for a system of three-spin groups... 相似文献
62.
63.
Physics of Atomic Nuclei - We have studied the mechanisms influencing production of cumulative pions and protons in the fragmentation of the incident deuterons into cumulative pions and protons... 相似文献
64.
65.
In this paper, we study the local linear convergence properties of a versatile class of Primal–Dual splitting methods for minimizing composite non-smooth convex optimization problems. Under the assumption that the non-smooth components of the problem are partly smooth relative to smooth manifolds, we present a unified local convergence analysis framework for these methods. More precisely, in our framework, we first show that (i) the sequences generated by Primal–Dual splitting methods identify a pair of primal and dual smooth manifolds in a finite number of iterations, and then (ii) enter a local linear convergence regime, which is characterized based on the structure of the underlying active smooth manifolds. We also show how our results for Primal–Dual splitting can be specialized to cover existing ones on Forward–Backward splitting and Douglas–Rachford splitting/ADMM (alternating direction methods of multipliers). Moreover, based on these obtained local convergence analysis result, several practical acceleration techniques are discussed. To exemplify the usefulness of the obtained result, we consider several concrete numerical experiments arising from fields including signal/image processing, inverse problems and machine learning. The demonstration not only verifies the local linear convergence behaviour of Primal–Dual splitting methods, but also the insights on how to accelerate them in practice. 相似文献
66.
67.
68.
G. Grätzer 《Algebra Universalis》2015,74(3-4):351-359
69.
Robert G. W. Anderson 《Ambix》2015,62(4):333-344
Following colonisation of South America by the Spanish, many new naturally occurring substances were sent to Europe. One of these was the silvery, unreactive metal, platinum, discovered in New Grenada in the mid-eighteenth century. It was often found in granular form, associated with gold, and the challenge to chemists was to refine it, produce it as wire or sheet, and determine its chemical properties. This interested the professor of chemistry at the University of Edinburgh, Joseph Black, who was able to obtain samples from London-based Spanish contacts, particularly Ignacio Luzuriaga. This paper examines how Black transmitted his knowledge of the metal to large numbers of students attending his annual course. 相似文献
70.