全文获取类型
收费全文 | 5218篇 |
免费 | 614篇 |
国内免费 | 437篇 |
专业分类
化学 | 905篇 |
晶体学 | 57篇 |
力学 | 482篇 |
综合类 | 98篇 |
数学 | 2967篇 |
物理学 | 1760篇 |
出版年
2024年 | 6篇 |
2023年 | 46篇 |
2022年 | 76篇 |
2021年 | 102篇 |
2020年 | 139篇 |
2019年 | 133篇 |
2018年 | 138篇 |
2017年 | 134篇 |
2016年 | 177篇 |
2015年 | 141篇 |
2014年 | 267篇 |
2013年 | 320篇 |
2012年 | 255篇 |
2011年 | 306篇 |
2010年 | 256篇 |
2009年 | 325篇 |
2008年 | 370篇 |
2007年 | 339篇 |
2006年 | 304篇 |
2005年 | 298篇 |
2004年 | 218篇 |
2003年 | 240篇 |
2002年 | 228篇 |
2001年 | 164篇 |
2000年 | 181篇 |
1999年 | 137篇 |
1998年 | 128篇 |
1997年 | 109篇 |
1996年 | 118篇 |
1995年 | 59篇 |
1994年 | 77篇 |
1993年 | 61篇 |
1992年 | 40篇 |
1991年 | 42篇 |
1990年 | 39篇 |
1989年 | 28篇 |
1988年 | 35篇 |
1987年 | 25篇 |
1986年 | 22篇 |
1985年 | 28篇 |
1984年 | 28篇 |
1983年 | 9篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 15篇 |
1976年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有6269条查询结果,搜索用时 15 毫秒
961.
The dependence of physical and mechanical properties of monolithic and foamed rigid polyurethanes on the content of flame
retardants was investigated at 293 and 98 K. The character of the influence of the content of trichloroethyl phosphate on
the ultimate tensile elongation and the coefficient of linear thermal expansion for monolithic and foamed polyurethanes at
a temperature of 98 K was established.
Latvian State Institute of Wood Chemistry, Riga, LV-1006 Latvia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35,
No. 5, pp. 671–676, September–October, 1999. 相似文献
962.
963.
Approximation of Metric Spaces by Partial Metric Spaces 总被引:1,自引:0,他引:1
Reinhold Heckmann 《Applied Categorical Structures》1999,7(1-2):71-83
Partial metrics are generalised metrics with non-zero self-distances. We slightly generalise Matthews' original definition of partial metrics, yielding a notion of weak partial metric. After considering weak partial metric spaces in general, we introduce a weak partial metric on the poset of formal balls of a metric space. This weak partial metric can be used to construct the completion of classical metric spaces from the domain-theoretic rounded ideal completion. 相似文献
964.
本文给出Fuzzy度量空间一些扩张型映象的不动点定理,这些结果发展和改进了普通度量空间中相应的结果。 相似文献
965.
966.
给出子考虑剪胀作用的线性软化土体中柱形孔扩张的应力、位移场解析解;根据体积平衡方程导出极限护孔压力和最大塑性区半径的解析表达式,较好地弥补了经典理论的不足;计算讨论了土体软化和剪胀特性对柱形扩孔的影响。 相似文献
967.
Arakelov and Faltings developed an admissible theory on regulararithmetic surfaces by using Arakelov canonical volume formson the associated Riemann surfaces. Such volume forms are inducedfrom the associated Kähler forms of the flat metric onthe corresponding Jacobians. So this admissible theory is inthe nature of Euclidean geometry, and hence is not quite compatiblewith the moduli theory of Riemann surfaces. In this paper, wedevelop a general admissible theory for arithmetic surfaces(associated with stable curves) with respect to any volume form.In particular, we have a theory of arithmetic surfaces in thenature of hyperbolic geometry by using hyperbolic volume formson the associated Riemann surfaces. Our theory is proved tobe useful as well: we have a very natural Weil function on themoduli space of Riemann surfaces, and show that in order tosolve the arithmetic Bogomolov-Miyaoka-Yau inequality, it issufficient to give an estimation for Petersson norms of somemodular forms. 1991 Mathematics Subject Classification: 11G30,11G99, 14H15, 53C07, 58A99. 相似文献
968.
We continue our study of families of pairs of matrix-valued meromorphic functions P(ρ,P) depending on two parameters p and P introduced in [2]. These include as special cases the projective Schur, Nevanlinna and Carathéodory classes. A two sided Carathéodory Fejér interpolation problem is defined and solved in P(ρ,P), using the fundamental matrix inequality method. A corresponding Schur algorithm is studied. Finally we also consider the case of functions (as opposed to pairs). 相似文献
969.
A large-scale one-centre expansion with a radial B-spline basis set is implemented for bound and continuum states. A Kohn-Sham
hamiltonian is employed with Hartree and exchange-correlation potentials calculated from the SCF electron density taken from
a previous LCAO calculation. An inverse iteration method is used to obtain the continuum wavefunction, from which the cross
section and asymmetry parameter are calculated. The convergence with respect to angular momentum and cut-off radius is analysed
for N2. The relevance of multipolar contributions even at large distances is shown and suggestions for further improvements are
given. In order to show that the present method is suitable to treat systems of moderate size, the (CH3)3N molecule has also been calculated and the results are compared with experiment.
Received: 19 May 1998 / Accepted: 20 August 1998 / Published online: 7 December 1998 相似文献
970.
Existence and iterative algorithms of solutions for generalized mixed quasi-variational inequalities
罗春林 《应用数学和力学(英文版)》1999,20(9):1038-1045
1 ProblemsLetHbearealHilbertspacewithnormandinnerproductsdenotedby‖·‖and〈·,·〉respectively.LetKbeaclosedconvexsubsetinHandf:H→Hbeasinglevaluedmapping.Theclassicalvariationalinequalityproblem(VIP(f,K))istofind^x∈K(^x),suchthat〈f(^x),y-^x〉≥0 (y∈K).(1)… 相似文献