全文获取类型
收费全文 | 202638篇 |
免费 | 1472篇 |
国内免费 | 425篇 |
专业分类
化学 | 104539篇 |
晶体学 | 3391篇 |
力学 | 10271篇 |
综合类 | 10篇 |
数学 | 21827篇 |
物理学 | 64497篇 |
出版年
2021年 | 1968篇 |
2020年 | 2008篇 |
2019年 | 2565篇 |
2018年 | 3656篇 |
2017年 | 3668篇 |
2016年 | 4807篇 |
2015年 | 2342篇 |
2014年 | 4295篇 |
2013年 | 8579篇 |
2012年 | 6835篇 |
2011年 | 8039篇 |
2010年 | 6454篇 |
2009年 | 6639篇 |
2008年 | 7634篇 |
2007年 | 7594篇 |
2006年 | 6692篇 |
2005年 | 5919篇 |
2004年 | 5637篇 |
2003年 | 5164篇 |
2002年 | 5152篇 |
2001年 | 5604篇 |
2000年 | 4135篇 |
1999年 | 3132篇 |
1998年 | 2698篇 |
1997年 | 2757篇 |
1996年 | 2540篇 |
1995年 | 2209篇 |
1994年 | 2326篇 |
1993年 | 2225篇 |
1992年 | 2522篇 |
1991年 | 2644篇 |
1990年 | 2552篇 |
1989年 | 2622篇 |
1988年 | 2531篇 |
1987年 | 2550篇 |
1986年 | 2411篇 |
1985年 | 3032篇 |
1984年 | 3101篇 |
1983年 | 2596篇 |
1982年 | 2562篇 |
1981年 | 2527篇 |
1980年 | 2335篇 |
1979年 | 2708篇 |
1978年 | 2671篇 |
1977年 | 2870篇 |
1976年 | 2872篇 |
1975年 | 2664篇 |
1974年 | 2602篇 |
1973年 | 2711篇 |
1972年 | 2085篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
S. N. Lakaev 《Theoretical and Mathematical Physics》1992,91(1):362-372
The existence of bound states and resonances of the Hamiltonian of a system ofN different quantum lattice particles with nonvanishingN-particle short-range interaction is proved. The dependence of the bound states and the resonances on the coupling constant and the quasimomentum is studied.Samarkand State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 91, No. 1, pp. 51–65, April, 1992. 相似文献
872.
Carmelo Nú¯nez 《Annali di Matematica Pura ed Applicata》1992,161(1):43-56
Summary Let K be a compact Hausdorff space and let E be a Banach space. We denote by C(K, E) the Banach space of all E-valued continuous functions defined on K, endowed with the supremum norm. We study in this paper Banach-Saks operators defined on C(K, E) spaces. We characterize these operators for a large class of compacts K (the scattered ones), or for a large class of Banach spaces E (the superreflexive ones). We also show by some examples that our theorems can not be extended directly.Partially supported by C.A.I.C.Y.T. grant 0338-84. The author wishes to thank Professor F.Bombal for his encouragement. 相似文献
873.
A. N. Kochubei 《Ukrainian Mathematical Journal》1992,44(7):836-840
A manifold M with semi-Riemannian almost product structure invariant relative to a transformation group G is considered. A connection with special G-invariance property is constructed in the corresponding bundle of frames.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 7, pp. 926–931, July, 1992. 相似文献
874.
875.
N. Kh. Kasymov 《Siberian Mathematical Journal》1992,33(6):1126-1128
Novosibirsk. Translated fromSibirskiî Matematicheskiî Zhurnal, Vol. 33, No. 6, pp. 195–198, November–December, 1992. 相似文献
876.
Translated from Sistemnoe Programmirovanie i Modeli Issledovaniya Operatsii, pp. 183–194, 1993. 相似文献
877.
A nonlinear quasi-steady model for the analysis of the dynamics of a loosely supported cylinder, which takes into account position-dependent nonlinear fluid forces as well as nonuniform flow, is formulated. The model includes an approximation for the equivalent viscous damping associated with energy dissipation on impact at the support. The nonlinear model shows reasonably good agreement with experiments, in predicting the observed bifurcations in the cylinder response. Comparison criteria include the standard orbital plots, time traces and response spectra. A borderline chaotic response is found to be predominant over the test velocity range. In this chaotic regime, the theoretical results were verified via attractor fractal-dimension calculations and saddle orbit distributions; theoretical values of these invariant measures compare reasonably well with their experimental counterparts. Two mechanisms leading to chaos have been identified for this system. The first is a switching mechanism , at the onset of impacting. The second, and more prevalent, is the type I intermittency route to chaos. 相似文献
878.
P Nürnberg I Barth E Fuhrmann C Lenzner T Losanova C Peters H P?che G Thiel 《Electrophoresis》1991,12(2-3):186-192
Germline and somatic instability of the human genome was studied, using synthetic oligonucleotides specific for simple repeat motifs. The following probes were used: (GTG)5, (GACA)4, (GATA)4, (CT)8, (TTAGGG)3, (GT)8, (GAA)6 and (GGAT)4. Each of them is unique with respect to the target regions recognized in the genome. Thus compilation of the various fingerprint data provides a complex map of the genome (and its deviations). While the fingerprints of differentiated somatic tissues never showed any alterations, in tumor tissues (namely gliomas) many changes could be detected. Most of the latter reflect secondary karyological aberrations. In nearly one third of the gliomas, drastically amplified and apparently monomorphic DNA fragments were identified. This marker should make it possible to deal with causal pathogenetic mechanisms as well as novel diagnostic strategies. 相似文献
879.
O. N. Ageev 《Mathematical Notes》1991,49(2):124-130
Translated from Matematicheskie Zametki, Vol. 49, No. 2, pp. 14–22, February, 1991. 相似文献
880.