全文获取类型
收费全文 | 316篇 |
免费 | 9篇 |
国内免费 | 9篇 |
专业分类
化学 | 155篇 |
晶体学 | 1篇 |
力学 | 10篇 |
数学 | 126篇 |
物理学 | 42篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 2篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 26篇 |
2012年 | 25篇 |
2011年 | 20篇 |
2010年 | 25篇 |
2009年 | 13篇 |
2008年 | 18篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 4篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1908年 | 2篇 |
1906年 | 1篇 |
排序方式: 共有334条查询结果,搜索用时 15 毫秒
101.
Catalin Florin Petre Abdelaaziz Azizi Caroline Olsen Abdelaziz Baçaoui Faïçal Larachi 《Journal of separation science》2008,31(22):3902-3910
A capillary electrophoretic protocol for the separation and quantification of the most important species potentially liberated during the cyanidation of gold sulfide‐rich ores was accomplished in this study. The separation of 11 ions: S2O32–, Cu(CN)32–, Fe(CN)64–, Fe(CN)63–, SCN–, Au(CN)2–, Ag(CN)2–, SO42–, OCN–, SO32–, and HS– was achieved using an indirect UV detection method. The robustness of the analytical protocol was tested by analyzing ions speciation during the cyanidation of two gold sulfide‐rich ores. The 1‐h cyanidation of the two ores released up to six complexes into solution: S2O32–, Cu(CN)32–, SCN–, Fe(CN)64–, OCN–, and SO42–. The mineralogy of the ore was found to influence directly the nature and the amount of the dissolved species. Conserving the cyanidation solution for 72 h after sampling resulted in 96% total sulfur recovery. These results allow us to conclude that the analytical protocol developed in this study can become very useful for the optimization of precious‐metals cyanidation plants. 相似文献
102.
The thermal position fluctuations of a single micron-sized sphere immersed in a fluid were recorded by optical trapping interferometry with nanometer spatial and microsecond temporal resolution. We find, in accord with the theory of Brownian motion including hydrodynamic memory effects, that the transition from ballistic to diffusive motion is delayed to significantly longer times than predicted by the standard Langevin equation. This delay is a consequence of the inertia of the fluid. On the shortest time scales investigated, the sphere's inertia has a small, but measurable, effect. 相似文献
103.
Spatiotemporal networks are studied in a photosensitive Belousov-Zhabotinsky medium that allows both local and nonlocal transmission of excitation. Local transmission occurs via propagating excitation waves, while nonlocal transmission takes place by nondiffusive jumps to destination sites linked to excited sites in the medium. Static, dynamic, and domain link networks are experimentally and computationally characterized. Transitions to synchronized behavior are exhibited with increasing link density, and power-law relations are observed for first-coverage time as a function of link probability. 相似文献
104.
We give an explicit L
2-representation of chiral charged fermions using the Hardy–Lebesgue octant decomposition. In the pure case such a representation has already been used by M. Sato in holonomic field theory. We study both pure and mixed cases. In the compact case, we rigorously define unsmeared chiral charged fermion operators inside the unit circle. Using chiral fermions, we orient our findings towards a functional analytic study of vertex algebras as one-dimensional quantum field theory. 相似文献
105.
Florin Radulescu 《Proceedings of the American Mathematical Society》2000,128(8):2405-2411
We prove that the algebra , a free group with finitely many generators, contains a subnormal operator such that the linear span of the set is weakly dense in . This is the analogue for the factor , finite, of a well known fact about the unilateral shift on a Hilbert space : the linear span of all the monomials is weakly dense in .
We also show that for a suitable space of square summable analytic functions, if is the projection from the Hilbert space of all square summable functions onto and is the unbounded operator of multiplication by on , then the (unbounded) operator is nonzero (with nonzero domain).
106.
107.
We prove exponential decay for derivatives of covariance operators on the lattice. This result is obtained by using random walk methods on the v-dimensional lattice and a certain estimate on the generating function of the one-dimensional random walk. The result is useful in the frame of the cluster and mean field expansion of continuous spin models on the lattice. 相似文献
108.
Copolymerization of ethylene and hexene has been carried out using Phillips' catalysts (chromium oxide deposited on silica) modified with small amounts of triethylaluminium [Al(C2H5)3], without solvent other than hexene itself and under constant ethylene pressure. The copolymers are highly disperse, not only in molecular weight but also in composition; the amount of hexene incorporated in the solid fraction is always less than 4%. Most of the hexene units are in a waxy fraction, which may account for a very high proportion of the copolymer produced. The behaviour of the catalyst is strongly dependent upon the amount of Al(C2H5)3 used. 相似文献
109.
110.
Pyrolysis gas chromatography of the polymers of 1,3,3,3-tetrafluoropropene, 3,3,4,4,5,5,5-heptafluoropentene-1 and of the copolymers of tetrafluoroethylene with the above and with 3,3,3-trifluoropropene and with isobutene in all instances gave only 3 to 19% of volatiles below C16, distributed among many peaks. This and the absence of significant char indicate predominantly a random scission mechanism of decomposition. 相似文献