全文获取类型
收费全文 | 228201篇 |
免费 | 1893篇 |
国内免费 | 756篇 |
专业分类
化学 | 105095篇 |
晶体学 | 2781篇 |
力学 | 13272篇 |
综合类 | 7篇 |
数学 | 46620篇 |
物理学 | 63075篇 |
出版年
2020年 | 1111篇 |
2019年 | 1172篇 |
2018年 | 11717篇 |
2017年 | 11491篇 |
2016年 | 8412篇 |
2015年 | 2361篇 |
2014年 | 2691篇 |
2013年 | 6585篇 |
2012年 | 8578篇 |
2011年 | 16426篇 |
2010年 | 9742篇 |
2009年 | 10178篇 |
2008年 | 12094篇 |
2007年 | 14276篇 |
2006年 | 5584篇 |
2005年 | 6238篇 |
2004年 | 5875篇 |
2003年 | 5770篇 |
2002年 | 4852篇 |
2001年 | 4558篇 |
2000年 | 3585篇 |
1999年 | 2704篇 |
1998年 | 2413篇 |
1997年 | 2317篇 |
1996年 | 2167篇 |
1995年 | 2009篇 |
1994年 | 1958篇 |
1993年 | 1817篇 |
1992年 | 2043篇 |
1991年 | 2179篇 |
1990年 | 1965篇 |
1989年 | 1973篇 |
1988年 | 1914篇 |
1987年 | 1812篇 |
1986年 | 1747篇 |
1985年 | 2238篇 |
1984年 | 2364篇 |
1983年 | 1933篇 |
1982年 | 2118篇 |
1981年 | 2000篇 |
1980年 | 1932篇 |
1979年 | 2072篇 |
1978年 | 2229篇 |
1977年 | 2085篇 |
1976年 | 2128篇 |
1975年 | 2035篇 |
1974年 | 2083篇 |
1973年 | 2084篇 |
1972年 | 1371篇 |
1971年 | 1218篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
981.
F. Severcan 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(1):127-134
Normal human, hemoglobin free erythrocyte ghosts were labelled with14C–N-Ethylmaleimide and incubated at two different temperatures 4°C and 37°C. Gel electrophoresis, autoradiography and nuclear scintillation counting techniques were used in analysing which proteins were labelled. The results of the experiments with incubation at 4°C and 37°C indicated that 35% of the NEM was associated with spectrin and 50% was bound to spectrin- actin complex. 相似文献
982.
In this paper, we study the growth of solutions of a first order linear differential equation. From this we verify that a
conjecture given by Brück is true under the restriction of the hyper order less than 1/2, and obtain some uniqueness theorems
of a nonconstant entire function and its first derivative sharing a nonzero constant CM. The results in this paper also improve
some known results. Some examples show that the results in this paper are best possible.
Project supported by the NSFC (NO. A0324617) and the RFDP (NO. 20060422049).
Received: 20 April 2006 Revised: 4 February 2007 相似文献
983.
Axel Ruhe 《BIT Numerical Mathematics》2007,47(2):239-240
984.
Iron alloys and aluminum were nitrogen implanted in a controlled oxygen atmosphere and the role of hydrogen on the surface etching mechanisms studied. The surface composition was analyzed by in situ photoemission electron spectroscopy (XPS). In iron alloys, hydrogen strongly etches oxygen, improving nitrogen retention on the surface. On the other hand, hydrogen removes nitrogen from aluminum surfaces, with a deleterious effect on the nitriding effectiveness. The oxygen removal in iron alloys is associated with the catalytic effect of electrons in d-orbitals and the nitrogen removal in aluminum is associated with a steric effect. 相似文献
985.
D. Chiladze J. Carbonell S. Dymov V. Glagolev M. Hartmann V. Hejny A. Kacharava I. Keshelashvili A. Khoukaz H.R. Koch V. Komarov P. Kulessa A. Kulikov G. Macharashvili Y. Maeda T. Mersmann S. Merzliakov S. Mikirtytchiants A. Mussgiller M. Nioradze H. Ohm F. Rathmann R. Schleichert H.J. Stein H. Ströher Yu. Uzikov S. Yaschenko C. Wilkin 《Physics letters. [Part B]》2006
986.
We demonstrate that the 3-power torsion points of the Jacobians of the principal modular curves X(3n) are fixed by the kernel of the canonical outer Galois representation of the pro-3 fundamental group of the projective line
minus three points. The proof proceeds by demonstrating the curves in question satisfy a two-part criterion given by Anderson
and Ihara. Two proofs of the second part of the criterion are provided; the first relies on a theorem of Shimura, while the
second uses the moduli interpretation.
Received: 30 September 2005 相似文献
987.
In this paper we present several results about local MV-algebras, extending existing results given for MV-chains. The role
of local MV-algebras in sheaf representation and weak boolean product is stressed and the relationship of local MV-algebras
with varieties of MV-algebras is analyzed.
Presented by S. Pulmannova.
Received November 11, 2005; accepted in final form December 20, 2005. 相似文献
988.
In this paper we consider operators of the form H=λ(-i∇), with λ analytic in a strip and with some specific growth conditions at infinity, and prove Hardy type estimates in L
2(ℝ
n
) with exponential weights. In fact we extend our previous results [19] from bounded analytic functions on a strip to analytic
functions with polynomial growth in that strip. 相似文献
989.
Instability of Solitary Waves in Nonlinear Composite Media 总被引:1,自引:0,他引:1
Ye Zhao 《应用数学学报(英文版)》2007,23(2):311-318
In this paper,we investigate a class of Hamiltonian systems arising in nonlinear composite media.By detailed analysis and computation we obtain a decaying estimates on the semigroup and prove the orbitalinstability of two families of explicit solitary wave solutions (slow family in anisotropic case and solitary wavesin isotropic case),which theoretically verify the related guess and numerical results. 相似文献
990.
Lanju Xu 《Discrete and Computational Geometry》2007,37(3):485-491
The lower bounds for the translative kissing numbers of superballs are studied in this note. We improve the bound given by
Larman and Zong. Furthermore, we give a constructive bound based on algebraic-geometry codes that also improves the bound
by Larman and Zong in almost all cases. 相似文献