全文获取类型
收费全文 | 1542篇 |
免费 | 43篇 |
国内免费 | 2篇 |
专业分类
化学 | 976篇 |
晶体学 | 13篇 |
力学 | 48篇 |
数学 | 230篇 |
物理学 | 320篇 |
出版年
2022年 | 11篇 |
2021年 | 14篇 |
2020年 | 16篇 |
2019年 | 18篇 |
2018年 | 12篇 |
2016年 | 31篇 |
2015年 | 19篇 |
2014年 | 26篇 |
2013年 | 67篇 |
2012年 | 73篇 |
2011年 | 84篇 |
2010年 | 43篇 |
2009年 | 46篇 |
2008年 | 68篇 |
2007年 | 79篇 |
2006年 | 77篇 |
2005年 | 70篇 |
2004年 | 54篇 |
2003年 | 48篇 |
2002年 | 51篇 |
2001年 | 43篇 |
2000年 | 21篇 |
1999年 | 16篇 |
1998年 | 24篇 |
1997年 | 13篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 39篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 20篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 18篇 |
1978年 | 26篇 |
1977年 | 20篇 |
1976年 | 20篇 |
1975年 | 20篇 |
1974年 | 12篇 |
1973年 | 18篇 |
1972年 | 14篇 |
排序方式: 共有1587条查询结果,搜索用时 15 毫秒
81.
Christopher J. Morris Brian Mary Sara Barron Omar Knio Ralph Hodgin Chadd May 《Journal of Physics and Chemistry of Solids》2010,71(2):84-1650
Research into nanoenergetic materials is enabling new capabilities for controlling exothermic reaction rates and energy output, as well as new methods for integrating these materials with conventional electronics fabrication techniques. Many reactions produce primarily heat, and in some cases it is desirable to increase the rate of heat release beyond what is typically observed. Here we investigate the Al-Ni intermetallic reaction, which normally propagates across films or foils at rates lower than 10 m/s. However, models and experiments indicate that local heating rates can be very high (107 K/s), and uniform heating of such a multilayer film can lead to a rapid, thermally explosive type of reaction. With the hopes of using a device to transduce electrical energy to kinetic energy of a flyer plate in the timescale of 100's of nanoseconds, we have incorporated a Ni/Al nanolayer film that locally heats upon application of a large electrical current. We observed flyer plate velocities in the 2-6 km/s range, corresponding to 4-36 kJ/g in terms of specific kinetic energy. Several samples containing Ni/Al films with different bilayer thicknesses were tested, and many produced additional kinetic energy in the 1.1-2.3 kJ/g range, as would be expected from the Ni-Al intermetallic reaction. These results provide evidence that nanoscale Ni/Al layers reacted in the timescale necessary to contribute to device output. 相似文献
82.
83.
Miller RI Kiefl RF Brewer JH Sonier JE Chakhalian J Dunsiger S Morris GD Price AN Bonn DA Hardy WH Liang R 《Physical review letters》2002,88(13):137002
Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa2Cu3O6+x is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa2Cu3O6.50 in applied fields of H = 1 T and H = 4 T reveal a feature in the high-field tail of the field distribution which is not present in optimally doped YBa2Cu3O6.95 and which fits well to a model with static magnetic fields in the vortex cores. The magnitude of the fields is estimated to be 18(2) G and decreases above T = 10 K. We discuss possible origins of the additional vortex core magnetism within the context of existing theories. 相似文献
84.
Distributed automated docking of flexible ligands to proteins: Parallel applications of AutoDock 2.4 总被引:17,自引:0,他引:17
Garrett M. Morris David S. Goodsell Ruth Huey Arthur J. Olson 《Journal of computer-aided molecular design》1996,10(4):293-304
Summary AutoDock 2.4 predicts the bound conformations of a small, flexible ligand to a nonflexible macromolecular target of known structure. The technique combines simulated annealing for conformation searching with a rapid grid-based method of energy evaluation based on the AMBER force field. AutoDock has been optimized in performance without sacrificing accuracy; it incorporates many enhancements and additions, including an intuitive interface. We have developed a set of tools for launching and analyzing many independent docking jobs in parallel on a heterogeneous network of UNIX-based workstations. This paper describes the current release, and the results of a suite of diverse test systems. We also present the results of a systematic investigation into the effects of varying simulated-annealing parameters on molecular docking. We show that even for ligands with a large number of degrees of freedom, root-mean-square deviations of less than 1 Å from the crystallographic conformation are obtained for the lowest-energy dockings, although fewer dockings find the crystallographic conformation when there are more degrees of freedom.The AutoDock 2.4 suite is written in ANSI C, and is supplied with Makefiles for the following platforms: Convex, DEC Alpha OSF/1, Hewlett-Packard Precision Architecture, Silicon Graphics, and Sun. The AutoDock suite of programs is freely available to the noncommercial scientific community and to educational establishments. Further information, including additional figures and MPEG animations showing all docked conformations for each test system, can be found at the following URL: http://www.scripps.edu/pub/olson-web/doc/autodock. 相似文献
85.
It is shown in this paper that if A is a closed normal subgroup of kω-topological groups G and H, then the free product of G and H with A amalgamated, G1AH, exists, is Hausdorff and indeed a kω-group. 相似文献
86.
87.
88.
89.
Carolyn E. M. Morris A. E. Alexander A. G. Parts 《Journal of polymer science. Part A, Polymer chemistry》1966,4(5):985-995
The polymerization of methyl acrylate in water and in dilute, aqueous, soap solutions, initiated by potassium peroxydisulfate, has been investigated, a dilatometric method being used to follow the conversion. It has been shown that small amounts of an anionic soap increase the rate of reaction while a cationic soap has the reverse effect. The change of molecular weight with conversion has also been examined as well as the effect of the exclusion of oxygen from the system. 相似文献
90.
The application of a dissipative Galerkin scheme to the numerical solution of the Korteweg de Vries (KdV) and Regularised Long Wave (RLW) equations, is investigated. The accuracy and stability of the proposed schemes is derived using a localised Fourier analysis. With cubic splines as basis functions, the errors in the numerical solutions of the KdV equation for different mesh-sizes and different amounts of dissipation is determined. It is shown that the Galerkin scheme for the RLW equation gives rise to much smaller errors (for a given mesh-size), and allows larger steps to be taken for the integrations in time (for a specified error tolerance). Also, the interaction of two solitons is compared for the KdV and RLW equations, and several differences in their behaviour are found. 相似文献