全文获取类型
收费全文 | 8668篇 |
免费 | 1582篇 |
国内免费 | 2380篇 |
专业分类
化学 | 4153篇 |
晶体学 | 34篇 |
力学 | 1335篇 |
综合类 | 42篇 |
数学 | 2362篇 |
物理学 | 4704篇 |
出版年
2023年 | 165篇 |
2022年 | 180篇 |
2021年 | 139篇 |
2020年 | 134篇 |
2019年 | 118篇 |
2018年 | 186篇 |
2017年 | 77篇 |
2016年 | 187篇 |
2015年 | 214篇 |
2014年 | 356篇 |
2013年 | 319篇 |
2012年 | 424篇 |
2011年 | 400篇 |
2010年 | 383篇 |
2009年 | 298篇 |
2008年 | 223篇 |
2007年 | 460篇 |
2006年 | 440篇 |
2005年 | 544篇 |
2004年 | 511篇 |
2003年 | 341篇 |
2002年 | 424篇 |
2001年 | 522篇 |
2000年 | 412篇 |
1999年 | 508篇 |
1998年 | 224篇 |
1997年 | 149篇 |
1996年 | 186篇 |
1995年 | 257篇 |
1994年 | 208篇 |
1993年 | 212篇 |
1992年 | 204篇 |
1991年 | 154篇 |
1990年 | 190篇 |
1989年 | 185篇 |
1988年 | 218篇 |
1987年 | 226篇 |
1986年 | 191篇 |
1985年 | 254篇 |
1984年 | 170篇 |
1983年 | 114篇 |
1982年 | 107篇 |
1981年 | 88篇 |
1975年 | 114篇 |
1959年 | 83篇 |
1958年 | 125篇 |
1957年 | 123篇 |
1956年 | 109篇 |
1955年 | 118篇 |
1954年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
LI JUNJIE 《高校应用数学学报(英文版)》1994,9(1):55-64
ANOTEONREGULARITYANDEXISTENCEOFSOLUTIONSFORACLASSOFNON-UNIFORMLYDEGENERATEELLIPTICEQUATIONS¥LIJUNJIE(Dept.ofMath.,ZhejiangUni... 相似文献
992.
In this paper,we demonstrate that the double-shift QL algorithm for an irreducible anti-symmetric iridiagonal matrix with the shifts being two eigenvalues of the 2×2 matrix in the left upper corner of this matrix is convergent and the convergence rale of Ms kind of algorithm is generally cubic. 相似文献
993.
Wo Gouwei Qin Taiyan Tang Renji 《Acta Mechanica Solida Sinica》1994,7(4):354-366
By using the hypothesis of the deformation of the straight bar and beamin mechanics of materials,a new engineering calculating model for a linear inclusion inplane is presented.Through the Kelvin's solution of a concentrated force,the inclusionproblem is reduced to solving a set of uncoupled singular integral equations which canbe solved by the numerical method of singular integral equation.Based on theseresults,several applicable examples including an inclusion-crack problem are calculatedand the results are quite satisfactory. 相似文献
994.
Calculations have been carried out on spin-polarized Auger electron emission from a seven-layer chromium (lO0)-film. The core and valence states concerning the Auger transition are obtained from a self-consistent full-potential linearized augmented plane wave calculation by using a repeated slab geometry. The calculations refer to experiments on the L3M23 V- and L3 VV-transRions that have recently been carried out by Heinzmann et al. The Auger spectrum obtained for the L3VV transition agrees relatively well with our calculations, whereas the observed L3M23V-Auger structure is considerably wider than that predicted by our theory. Nevertheless, the spin-polarization in the latter case, which is about -13%, is in fair agreement with the experiment, different from the L3VV-transition where the experiment yields -10% as opposed to the theoretical value of -25%. We give possible reasons for the origin of these discrepancies. 相似文献
995.
996.
In this work we present the behavior of a very compact XeCl laser system.Itconsists of an oscillator and an amplifier,both with lateral UV-preionization.Both dischargeelectrodes are contained in a single vessel.An unstable optical cavity is applied to the oscilla-tor.An output beam of 105 mJ,with a brightness of 5.5× 10~(l3)Wcm~(-2)Sr~(-1) and with a diver-gence of 0.9 mrad has been obtained. 相似文献
997.
A UNIFIED ENERGY APPROACH TO A CLASS OF MICROMECHANICS MODELS FOR MICROCRACKED SOLIDS 总被引:2,自引:0,他引:2
Y.Huang K.C.Hwang 《Acta Mechanica Solida Sinica》1995,8(2):110-120
Micromechanics models have been developed for the determination ofthe elastic moduli of microcracked solids based on different approaches andinterpretations,including the dilute or non-interacting solution,the Mori-Tanakamethod,the self-consistent method,and the generalized self-consistent method.It isshown in the present study that all these micromechanics models can be unified withinan energy-equivalence framework,and that they differ only in the way in which themicrocrack opening and sliding displacements are evaluated.Relevance to thedifferential methods and the verification of these models are discussed. 相似文献
998.
999.
EXISTENCEANDUNIQUENESSOFTHEENTROPYSOLUTIONTOANONLINEARHYPERBOLICEQUATION¥R.EYMARD;T.GALLOUET;R.HERBIN(LaboratoireCentraldesPo... 相似文献
1000.
Spatial Nonparametric Regression Estimation: Non-isotropic Case 总被引:3,自引:0,他引:3
Zu-di Lu Xing ChenInstitute of Systems Science Academy of Mathematics Systems Sciences Chinese Academy of Sciences. Beijing ChinaDepartment of Statistics Yunnan University Kunming China 《应用数学学报(英文版)》2002,18(4):641-656
Data collected on the surface of the earth often has spatial interaction. In this paper, a non-isotropic mixing spatial data process is introduced, and under such a spatial structure a nonparametric kernel method is suggested to estimate a spatial conditional regression. Under mild regularities, sufficient conditions are derived to ensure the weak consistency as well as the convergence rates for the kernel estimator. Of interest are the following: (1) All the conditions imposed on the mixing coefficient and the bandwidth are simple; (2) Differently from the time series setting, the bandwidth is found to be dependent on the dimension of the site in space as well; (3) For weak consistency, the mixing coefficient is allowed to be unsummable and the tendency of sample size to infinity may be in different manners along different direction in space; (4) However, to have an optimal convergence rate, faster decreasing rates of mixing coefficient and the tendency of sample size to infinity along each direction a 相似文献