全文获取类型
收费全文 | 19094篇 |
免费 | 743篇 |
国内免费 | 99篇 |
专业分类
化学 | 13087篇 |
晶体学 | 120篇 |
力学 | 422篇 |
数学 | 2894篇 |
物理学 | 3413篇 |
出版年
2023年 | 122篇 |
2022年 | 172篇 |
2021年 | 269篇 |
2020年 | 377篇 |
2019年 | 397篇 |
2018年 | 234篇 |
2017年 | 236篇 |
2016年 | 600篇 |
2015年 | 556篇 |
2014年 | 644篇 |
2013年 | 1024篇 |
2012年 | 1115篇 |
2011年 | 1249篇 |
2010年 | 745篇 |
2009年 | 659篇 |
2008年 | 1036篇 |
2007年 | 1021篇 |
2006年 | 949篇 |
2005年 | 883篇 |
2004年 | 775篇 |
2003年 | 638篇 |
2002年 | 605篇 |
2001年 | 310篇 |
2000年 | 291篇 |
1999年 | 274篇 |
1998年 | 242篇 |
1997年 | 231篇 |
1996年 | 264篇 |
1995年 | 247篇 |
1994年 | 217篇 |
1993年 | 212篇 |
1992年 | 199篇 |
1991年 | 175篇 |
1990年 | 174篇 |
1989年 | 175篇 |
1988年 | 149篇 |
1987年 | 125篇 |
1986年 | 115篇 |
1985年 | 166篇 |
1984年 | 161篇 |
1983年 | 126篇 |
1982年 | 153篇 |
1981年 | 157篇 |
1980年 | 132篇 |
1979年 | 140篇 |
1978年 | 158篇 |
1977年 | 115篇 |
1976年 | 100篇 |
1975年 | 117篇 |
1974年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Martin H. Gutknecht 《Numerische Mathematik》1989,56(6):547-589
Summary We discuss first the block structure of the Newton-Padé table (or, rational interpolation table) corresponding to the double sequence of rational interpolants for the data{(z
k, h(zk)}
k
=0. (The (m, n)-entry of this table is the rational function of type (m,n) solving the linearized rational interpolation problem on the firstm+n+1 data.) We then construct continued fractions that are associated with either a diagonal or two adjacent diagonals of this Newton-Padé table in such a way that the convergents of the continued fractions are equal to the distinct entries on this diagonal or this pair of diagonals, respectively. The resulting continued fractions are generalizations of Thiele fractions and of Magnus'sP-fractions. A discussion of an some new results on related algorithms of Werner and Graves-Morris and Hopkins are also given.Dedicated to the memory of Helmut Werner (1931–1985) 相似文献
72.
Martin Charles Golumbic 《Graphs and Combinatorics》1988,4(1):307-321
Let be a family of sets. The intersection graph of is obtained by representing each set in by a vertex and connecting two vertices by an edge if and only if their corresponding sets intersect. Of primary interest are those classes of intersection graphs of families of sets having some specific topological or other structure. The grandfather of all intersection graphs is the class of interval graphs, that is, the intersection graphs of intervals on a line.The scope of research that has been going on in this general area extends from the mathematical and algorithmic properties of intersection graphs, to their generalizations and graph parameters motivated by them. In addition, many real-world applications involve the solution of problems on such graphs.In this paper a number of topics in algorithmic combinatorics which involve intersection graphs and their representative families of sets are presented. Recent applications to computer science are also discussed. The intention of this presentation is to provide an understanding of the main research directions which have been investigated and to suggest possible new directions of research. 相似文献
73.
74.
75.
Anjos JC Appel JA Bean A Bracker SB Browder TE Cremaldi LM Elliott JR Escobar CO Estabrooks P Gibney MC Hartner GF Karchin PE Kumar BR Losty MJ Luste GJ Mantsch PM Martin JF McHugh S Menary SR Morrison RJ Nash T Nauenberg U Ong P Pinfold J Punkar G Purohit MV Raab JR Santoro AF Sidhu JS Sliwa K Sokoloff MD Souza MH Spalding WJ Streetman ME Stundia AB Witherell MS 《Physical review letters》1988,60(14):1379-1381
76.
77.
R. Kleiss A. D. Martin W. J. Stirling 《Zeitschrift fur Physik C Particles and Fields》1988,39(3):393-398
We study means of identifying top quarks of mass in the range 70–120 GeV at the CERN and FNAL \(\bar pp\) colliders. We show that “W+dijet” production presents a serious background to the conventional “isolated electron+dijet” signature of top. We study an improved signature, calculate the expected event rates, and discuss the determination of the mass of the top quark. 相似文献
78.
79.
80.
Hatchling American alligators, Alligator mississippiensis , display a diel rhythm of extra-retinal (non-pineal) photosensitivity. There is a bimodal pattern in the threshold fluence rate required for initiating and effecting extra-retinally-mediated phototaclic responses. Significantly greater threshold fluence rates are required in the photophase than the scotophasc of a 12 h light: 12 h dark cycle. Under constant darkness there continues an endogenous, apparently circadian rhythm of extra-retinal photosensitivity. In all cases there is a significantly greater photosensitivity at lower temperatures. 相似文献