全文获取类型
收费全文 | 22850篇 |
免费 | 491篇 |
国内免费 | 449篇 |
专业分类
化学 | 4066篇 |
晶体学 | 934篇 |
力学 | 403篇 |
综合类 | 45篇 |
数学 | 14474篇 |
物理学 | 3868篇 |
出版年
2023年 | 62篇 |
2022年 | 196篇 |
2021年 | 161篇 |
2020年 | 168篇 |
2019年 | 451篇 |
2018年 | 465篇 |
2017年 | 304篇 |
2016年 | 348篇 |
2015年 | 362篇 |
2014年 | 670篇 |
2013年 | 1515篇 |
2012年 | 611篇 |
2011年 | 1751篇 |
2010年 | 1573篇 |
2009年 | 1496篇 |
2008年 | 1603篇 |
2007年 | 1605篇 |
2006年 | 1210篇 |
2005年 | 1018篇 |
2004年 | 886篇 |
2003年 | 705篇 |
2002年 | 691篇 |
2001年 | 455篇 |
2000年 | 455篇 |
1999年 | 444篇 |
1998年 | 437篇 |
1997年 | 337篇 |
1996年 | 393篇 |
1995年 | 391篇 |
1994年 | 368篇 |
1993年 | 282篇 |
1992年 | 273篇 |
1991年 | 181篇 |
1990年 | 188篇 |
1989年 | 179篇 |
1988年 | 110篇 |
1987年 | 132篇 |
1986年 | 93篇 |
1985年 | 171篇 |
1984年 | 130篇 |
1983年 | 74篇 |
1982年 | 111篇 |
1981年 | 135篇 |
1980年 | 107篇 |
1979年 | 66篇 |
1978年 | 108篇 |
1977年 | 94篇 |
1976年 | 91篇 |
1975年 | 40篇 |
1974年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
M. Frigon 《Journal of Fixed Point Theory and Applications》2007,1(2):189-194
We present results on the global existence of analytic solutions to the Cauchy problem in starshaped or convex complex domains.
No growth conditions are imposed. Our results rely on a notion of solution-tube that we introduce.
à la mémoire de Jean Leray 相似文献
52.
The new phenylpropanoid diglycoside ligusinenoside A ( 1 ), and the two new 8,4′‐oxyneolignan(‘8‐O‐4′‐neolignan’) diglycosides ligusinenosides B ( 2 ) and C ( 3 ), together with nine known compounds, were isolated from the rhizomes of Ligusticum sinensis Oliv. The structures of 1 – 3 were elucidated on the basis of spectroscopic analyses. 相似文献
53.
Marilyn Breen 《Journal of Geometry》1989,36(1-2):8-16
LetS be a compact, simply connected set inR
2. If every boundary point ofS is clearly visible viaS from at least one of the three pointsa, b, c, thenS is a union of three starshaped sets whose kernels containa, b, c, respectively. The result fails when the number three is replaced by four.As a partial converse, ifS is a union of three starshaped sets whose kernels containa, b, c, respectively, then the set of points in the boundary ofS clearly visible from at least one ofa, b, orc is dense in the boundary ofS.Supported in part by NSF grant DMS-8705336. 相似文献
54.
Valery Agoshkov Paola Gervasio Alfio Quarteroni 《Mediterranean Journal of Mathematics》2006,3(2):147-176
New domain decomposition methods (DDM) based on optimal control approach are introduced for the coupling of first and second
order equations on overlapping subdomains. Several cost functionals and control functions are proposed. Uniqueness and existence
results are proved for the coupled problem, and the convergence of iterative processes is analyzed.
The work was supported by the Russian Foundation for Basic Research (04-01-00615) and it was partly carried out while the
first author was visiting the IACS at EPFL. 相似文献
55.
The authors give a consistent affirmative response to a question of Juhász, Soukup and Szentmiklóssy: If GCH fails, there are (many) extraresolvable, not maximally resolvable Tychonoff spaces. They show also in ZFC that for ω<λ?κ, no maximal λ-independent family of λ-partitions of κ is ω-resolvable. In topological language, that theorem translates to this: A dense, ω-resolvable subset of a space of the form (DI(λ)) is λ-resolvable. 相似文献
56.
Martin Loebl 《Advances in Mathematics》2007,211(2):546-565
We define a q-chromatic function and q-dichromate on graphs and compare it with existing graph functions. Then we study in more detail the class of general chordal graphs. This is partly motivated by the graph isomorphism problem. Finally we relate the q-chromatic function to the colored Jones function of knots. This leads to a curious expression of the colored Jones function of a knot diagram K as a chromatic operator applied to a power series whose coefficients are linear combinations of long chord diagrams. Chromatic operators are directly related to weight systems by the work of Chmutov, Duzhin, Lando and Noble, Welsh. 相似文献
57.
Historians have always seen jabr (restoration) and muqābala (confrontation) as technical terms for specific operations in Arabic algebra. This assumption clashes with the fact that the words were used in a variety of contexts. By examining the different uses of jabr, muqābala, ikmāl (completion), and radd (returning) in the worked-out problems of several medieval mathematics texts, we show that they are really nontechnical words used to name the immediate goals of particular steps. We also find that the phrase al-jabr wa'l-muqābala was first used within the solutions of problems to mean al-jabr and/or al-muqābala, and from there it became the name of the art of algebra. 相似文献
58.
We consider Sinai’s random walk in random environment. We prove that infinitely often (i.o.) the size of the concentration neighborhood of this random walk is bounded almost surely. We also get that i.o. the maximal distance between two favorite sites is bounded almost surely. 相似文献
59.
Fidel Casarrubias-Segura Alejandro Ramírez-Páramo 《Topology and its Applications》2007,154(7):1307-1313
In this paper we make use of the Pol-Šapirovski?'s technique to prove several cardinal inequalities, which generalize other well-known inequalities. 相似文献
60.
The q-Catalan numbers studied by Carlitz and Riordan are polynomials in q with nonnegative coefficients. They evaluate, at q = 1, to the Catalan numbers: 1, 1, 2, 5, 14,…, a log-convex sequence. We use a combinatorial interpretation of these polynomials
to prove a q-log-convexity result. The sequence of q-Catalan numbers is not q-log-convex in the narrow sense used by other authors, so our work suggests a more flexible definition of q-log convex be adopted.
Received January 2, 2007 相似文献