全文获取类型
收费全文 | 8860篇 |
免费 | 1624篇 |
国内免费 | 2519篇 |
专业分类
化学 | 4320篇 |
晶体学 | 39篇 |
力学 | 1342篇 |
综合类 | 47篇 |
数学 | 2466篇 |
物理学 | 4789篇 |
出版年
2023年 | 87篇 |
2022年 | 146篇 |
2021年 | 128篇 |
2020年 | 137篇 |
2019年 | 112篇 |
2018年 | 185篇 |
2017年 | 82篇 |
2016年 | 188篇 |
2015年 | 219篇 |
2014年 | 366篇 |
2013年 | 328篇 |
2012年 | 435篇 |
2011年 | 412篇 |
2010年 | 400篇 |
2009年 | 315篇 |
2008年 | 241篇 |
2007年 | 469篇 |
2006年 | 456篇 |
2005年 | 563篇 |
2004年 | 528篇 |
2003年 | 358篇 |
2002年 | 442篇 |
2001年 | 534篇 |
2000年 | 435篇 |
1999年 | 540篇 |
1998年 | 249篇 |
1997年 | 174篇 |
1996年 | 205篇 |
1995年 | 277篇 |
1994年 | 233篇 |
1993年 | 229篇 |
1992年 | 222篇 |
1991年 | 172篇 |
1990年 | 200篇 |
1989年 | 196篇 |
1988年 | 221篇 |
1987年 | 229篇 |
1986年 | 194篇 |
1985年 | 256篇 |
1984年 | 171篇 |
1983年 | 116篇 |
1982年 | 115篇 |
1981年 | 91篇 |
1975年 | 114篇 |
1959年 | 84篇 |
1958年 | 126篇 |
1957年 | 128篇 |
1956年 | 110篇 |
1955年 | 119篇 |
1954年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 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.
利用固相反应烧结法制备了La067Pb033MnO3单相多晶样品.研究了其结构、磁性及输运特性.结果表明,样品呈菱面相晶体结构,空间群为R3C,居里温度TC(=353K)非常接近TMI(=360K).在居里温度附近,发生铁磁-顺磁转变,导电特性由金属特征向半导体特征过渡.磁电阻在居里点达到极大值.当H=16T时,磁电阻的极大值为145%;当H=08T时,磁电阻的极大值为9%.输运性质表明,TTMI时
关键词:
磁电阻
输运特性
磁极化子
钙钛石 相似文献
995.
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
996.
997.
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
998.
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
999.
The structures of Y2Fe17-xCrx are simulated by the ab initio potentials. The site preference of Cr atom in Y2Fe17 is evaluated and the order is determined as 4f, 12j, which is close to the experimental result. Based on the site preference behavior, the calculated parameters and the atom sites of Y-Fe-Cr system are studied. The result corresponds well to observed data. Further, the DOS of the relaxed structures are calculated and the variation in Curie temperature is explained qualitatively by the spin-fluctuation theory. 相似文献
1000.