全文获取类型
收费全文 | 8519篇 |
免费 | 249篇 |
国内免费 | 18篇 |
专业分类
化学 | 5162篇 |
晶体学 | 31篇 |
力学 | 156篇 |
数学 | 1192篇 |
物理学 | 2245篇 |
出版年
2023年 | 47篇 |
2021年 | 75篇 |
2020年 | 105篇 |
2019年 | 90篇 |
2018年 | 78篇 |
2017年 | 75篇 |
2016年 | 229篇 |
2015年 | 178篇 |
2014年 | 198篇 |
2013年 | 378篇 |
2012年 | 359篇 |
2011年 | 431篇 |
2010年 | 246篇 |
2009年 | 211篇 |
2008年 | 373篇 |
2007年 | 378篇 |
2006年 | 328篇 |
2005年 | 330篇 |
2004年 | 288篇 |
2003年 | 238篇 |
2002年 | 209篇 |
2001年 | 162篇 |
2000年 | 133篇 |
1999年 | 130篇 |
1998年 | 113篇 |
1997年 | 123篇 |
1996年 | 133篇 |
1995年 | 130篇 |
1994年 | 117篇 |
1993年 | 122篇 |
1992年 | 124篇 |
1991年 | 92篇 |
1990年 | 79篇 |
1989年 | 112篇 |
1988年 | 106篇 |
1987年 | 113篇 |
1986年 | 89篇 |
1985年 | 93篇 |
1984年 | 108篇 |
1983年 | 91篇 |
1982年 | 112篇 |
1981年 | 107篇 |
1980年 | 91篇 |
1979年 | 91篇 |
1978年 | 79篇 |
1977年 | 83篇 |
1976年 | 72篇 |
1975年 | 84篇 |
1974年 | 56篇 |
1973年 | 68篇 |
排序方式: 共有8786条查询结果,搜索用时 9 毫秒
101.
The job-shop problem is one of the most difficult NP-hard scheduling problems. A 10×10-problem published in 1963 has been solved only recently by Carlier and Pinson using a branch and bound method. Other branch and bound algorithms have been developed recently. The efficiency of all these branch and bound methods relies on the concept of immediate selection which allows to introduce order relations on the setI of all operations to be processed on the same machine before branching. We present new algorithms for immediate selection. Among them are
- anO(max {n logn,f})-algorithm for fixing all disjunctions induced by cliques;
- anO(n 2)-algorithm based on concepts which are different from those used by Carlier and Pinson.
102.
103.
104.
Bockhorst M. Burbach G. Burgwinkel R. Empt J. Guse B. Guse B. Haas K. -M. Hannappel J. Heinloth K. Hey T. Hoffmann-Rothe P. Honscheid K. Jahnen T. Jakob H. P. Jöpen N. Jüngst H. Kirch U. Klein F. -J. Kostrewa D. Lindemann L. Link J. Manns J. Menze D. Merkel H. Merkel R. Neuerburg W. Paul E. Plötzke R. Schenk U. Schmidt S. Scholmann J. Schütz P. Schultz-Coulon H. -C. Schweitzer M. Schwille W. J. Tran M. -Q. Umlauf G. Vogl W. Wedemeyer R. Wehnes F. Wißkirchen J. Wolf A. 《Zeitschrift fur Physik C Particles and Fields》1994,63(1):37-47
The reactions pK
+ and pK
+ 0 have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the polarization and, for the first time, the 0 polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°–180°). The polarization of both and 0 is substantial at all energies and varies strongly with the production angle.This work is supported by the Bundesminister für Forschung und Technologie (BMFT), FK 06 BN 621 I 相似文献
105.
106.
The anisotropic homogeneous 3 is isometrically globally embedded into a nine-dimensional Euclidean or pseudo-Euclidean space. In a special case the Euclidean space is six-dimensional. The space-sections of the anti-Mach metric appear as a submanifold of theE
9. We obtain also the isometric embedding ofSO(3) with its natural Killing metric. 相似文献
107.
Lopez-Martens A Hannachi F Dossing T Schück C Collatz R Gueorguieva E Vieu C Leoni S Herskind B Khoo TL Lauritsen T Ahmad I Blumenthal DJ Carpenter MP Gassmann D Janssens RV Nisius D Korichi A Bourgeois C Astier A Ducroux L Le Coz Y Meyer M Redon N Sharpey-Schafer JF Wilson AN Korten W Bracco A Lucas R 《Physical review letters》1996,77(9):1707-1710
108.
Theorem 3 gives a condition when two -weights can be ``pasted' together to yield another -weight. It is subsequently used in Example 6 to give an example that shows that a necessary condition by Gohberg, Krupnik, and Spitkovsky is not sufficient.
109.
The ligand-field spectrum of [Cr(NH(3))(4)F(2)]AsF(6) has been pressure-tuned up to 100 kbar. The parametrical analysis shows that the absolute values of the two independent tetragonalities of the chromophoric ion both decrease with increasing isotropic pressure so that the molecular ion becomes more isotropic. Moreover, the Cr-N single bonds appear to be more compressible than the Cr-F bonds, for which it is parametrically clear that they have a partial multiple-bond character. While the spectrochemical parameter for F(-), Delta(F), increases with pressure, its two components Delta(sigma)(F) and Delta(pi)(F) decrease. It is confirmed that nephelauxetism increases with pressure. 相似文献
110.