全文获取类型
收费全文 | 4611篇 |
免费 | 64篇 |
国内免费 | 13篇 |
专业分类
化学 | 3115篇 |
晶体学 | 12篇 |
力学 | 46篇 |
数学 | 719篇 |
物理学 | 796篇 |
出版年
2016年 | 61篇 |
2015年 | 52篇 |
2014年 | 71篇 |
2013年 | 122篇 |
2012年 | 94篇 |
2011年 | 122篇 |
2010年 | 92篇 |
2009年 | 65篇 |
2008年 | 105篇 |
2007年 | 139篇 |
2006年 | 91篇 |
2005年 | 124篇 |
2004年 | 122篇 |
2003年 | 85篇 |
2002年 | 81篇 |
2001年 | 69篇 |
2000年 | 78篇 |
1999年 | 62篇 |
1998年 | 40篇 |
1996年 | 52篇 |
1995年 | 43篇 |
1994年 | 63篇 |
1993年 | 47篇 |
1992年 | 51篇 |
1991年 | 47篇 |
1989年 | 41篇 |
1988年 | 41篇 |
1987年 | 52篇 |
1986年 | 62篇 |
1985年 | 63篇 |
1984年 | 50篇 |
1983年 | 43篇 |
1982年 | 62篇 |
1981年 | 75篇 |
1980年 | 61篇 |
1979年 | 44篇 |
1978年 | 64篇 |
1977年 | 53篇 |
1976年 | 48篇 |
1974年 | 49篇 |
1972年 | 44篇 |
1971年 | 40篇 |
1967年 | 40篇 |
1965年 | 55篇 |
1964年 | 107篇 |
1963年 | 133篇 |
1962年 | 176篇 |
1961年 | 158篇 |
1960年 | 150篇 |
1958年 | 54篇 |
排序方式: 共有4688条查询结果,搜索用时 15 毫秒
61.
The ASED-MO method has been used to gather electronic and energetic information on Pd deposits on Ni(111) and Pd atom inclusion in the first Ni layer since these model catalysts exhibit a striking catalytic efficiency towards butadiene hydrogenation. The electronic structure of Pd atoms is strongly altered compared with pure Pd. A Pd(4d)→Pd(5s) electronic transfer occurs in the case of the deposit when a slight similar transfer and a charge transfer from Pd to surrounding Ni takes place in the case of the inclusion. Those results are consistent with XPS experimental data. A low density of states, near the Fermi level, is also observed. The optimal geometrical situation for Pd deposits is found to be 2D-aggregates (in pseudoepitaxy or pseudomorphy with the underlying Ni surface, depending on the aggregate size). Small aggregates (part of the first Ni layer) are found to be the most stable in the case of a Pd inclusion in the Ni with a Pd---Pd distance of 2.64 Å, in agreement with available EXAFS experimental data. 相似文献
62.
In a recent paper [O. Bärwald, R.W. Gebert, M. Günaydin and H. Nicolai, preprint KCL-MTH-97-22, IASSNS-HEP-97/20, PSU-TH-178, AEI-029, hep-th/9703084, to appear in Commun. Math. Phys.] it was conjectured that the imaginary simple roots of the Borcherds algebra II9,1 at level 1 are its only ones. We here propose an independent test of this conjecture, establishing its validity for all roots of norm − 8. However, the conjecture fails for roots of norm −10 and beyond, as we show by computing the simple multiplicities down to norm −24, which turn out to be remarkably small in comparison with the corresponding E10 multiplicities. Our derivation is based on a modified denominator formula combining the denominator formulas for E10 and II9,1, and provides an efficient method for determining the imaginary simple roots. In addition, we compute the E10 multiplicities of all roots up to height 231, including levels up to l = 6 and norms −42. 相似文献
63.
Hermann Thorisson 《Probability Theory and Related Fields》1994,99(4):477-483
Summary The result linking shift-coupling to time-average total variation convergence and to the invariant -field is extended to continuous time and an analogous result established linking -couplings to smooth total variation convergence and to a smooth tail -field. Shift- and -coupling inequalities are presented. 相似文献
64.
Spectral methods for pantograph-type differential and integral equations with multiple delays 总被引:1,自引:0,他引:1
We analyze the convergence properties of the spectral method when used to approximate smooth solutions of delay differential
or integral equations with two or more vanishing delays. It is shown that for the pantograph-type functional equations the
spectral methods yield the familiar exponential order of convergence. Various numerical examples are used to illustrate these
results.
相似文献
65.
We consider the blow-up behavior of Hammerstein-type delay Volterra integral equations (DVIEs). Two types of delays, i.e., vanishing delay (pantograph delay) and non-vanishing delay (constant delay), are considered. With the same assumptions of Volterra integral equations (VIEs), in a similar technology to VIEs, the blow-up conditions of the two types of DVIEs are given. The blow-up behaviors of DVIEs with non-vanishing delay vary with different initial functions and the length of the lag, while DVIEs with pantograph delay own the same blow-up behavior of VIEs. Some examples and applications to delay differential equations illustrate this influence. 相似文献
66.
The cellular functions of most RNA molecules involve protein binding, and non-Watson-Crick base pairs are hallmark sites for interactions with proteins. The determination of three-dimensional structures of RNA-peptide and RNA-protein complexes reveals the molecular basis of non-Watson-Crick base-pair recognition. 相似文献
67.
Sami El Deeb Hermann Wätzig Deia Abd El‐Hady Cari Sänger‐van de Griend Gerhard K. E. Scriba 《Electrophoresis》2016,37(12):1591-1608
This review updates and follows‐up a previous review by highlighting recent advancements regarding capillary electromigration methodologies and applications in pharmaceutical analysis. General approaches such as quality by design as well as sample injection methods and detection sensitivity are discussed. The separation and analysis of drug‐related substances, chiral CE, and chiral CE‐MS in addition to the determination of physicochemical constants are addressed. The advantages of applying affinity capillary electrophoresis in studying receptor–ligand interactions are highlighted. Finally, current aspects related to the analysis of biopharmaceuticals are reviewed. The present review covers the literature between January 2013 and December 2015. 相似文献
68.
69.
70.
The existence of electrophoretic mobility at high electrolyte concentrations defines a remarkable peculiarity in the electrosurface characteristics of soft particles. According to Ohshima [H. Ohshima, Colloids Surf. 103 (1995) 249], this effect is caused by the electroosmotic flow within the soft particle shell. An explanation supporting Ohshima's conclusion can be derived from classic electrokinetic theories. Based on the Henry theory [D.C. Henry, Proc. R. Soc. London Ser. A 133 (1931) 106], we demonstrate that the electrophoretic mobility of soft particles does not disappear at decinormal concentration. 相似文献