全文获取类型
收费全文 | 272篇 |
免费 | 1篇 |
国内免费 | 3篇 |
专业分类
化学 | 142篇 |
晶体学 | 2篇 |
力学 | 16篇 |
数学 | 37篇 |
物理学 | 79篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 10篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1970年 | 2篇 |
1934年 | 2篇 |
1933年 | 3篇 |
1907年 | 2篇 |
排序方式: 共有276条查询结果,搜索用时 0 毫秒
81.
Growth rate measurements of β-cyclodextrin in water were performed both ways. Firstly, experiments were conducted with single monocrystals located in a supersaturation-controlled flow cell. Diffusional limitations and perturbations due to a competition between surface secondary nucleation and growth at high level of supersaturation have been put in evidence. The evolution of the growth rate with supersaturation has been modelled with a BCF law, assuming a screw dislocation mechanism. Secondly seeded cooling batch trials have been carried on in a well-mixed suspension crystallizer in order to assess the growth rate of the seeds. Refractometry was used as an in situ sensor for measuring the evolution of the concentration of the solute. Measurements of the crystals size distribution of the seeds and of the final crystals are performed off line with laser diffraction technique. A kinetic law with three parameters allows a consistent assessment of the growth of the seeds. The comparison of the two sets of data shows that overall growth rate of the seed is partially limited by diffusion. Nevertheless, the estimation of a surface integration growth kinetic coefficient from batch trials is rather difficult. The theoretical framework of nucleation models developed by Mersmann et al. (Crystallization Technology Handbook, second ed., Marcel Dekker, New York, 2001, pp. 45–80 and 81–144) coupled with the estimated growth kinetics can therefore be used to better monitor the seeding process during batch crystallization operations so as to favor the growth of the seed crystals. 相似文献
82.
83.
84.
Dillmann I Kratz KL Wöhr A Arndt O Brown BA Hoff P Hjorth-Jensen M Köster U Ostrowski AN Pfeiffer B Seweryniak D Shergur J Walters WB;ISOLDE Collaboration 《Physical review letters》2003,91(16):162503
First beta- and gamma-spectroscopic decay studies of the N=82 r-process "waiting-point" nuclide 130Cd have been performed at CERN/ISOLDE using the highest achievable isotopic selectivity. Several nuclear-physics surprises have been discovered. The first one is the unanticipatedly high energy of 2.12 MeV for the [pi g(9/2) multiply sign in circle nu g(7/2)] 1(+) level in 130In, which is fed by the main Gamow-Teller transition. The second surprise is the rather high Q(beta) value of 8.34 MeV, which is in agreement only with recent mass models that include the phenomenon of N=82 shell quenching. Possible implications of these new results on the formation of the A approximately 130 r-process abundance peak are presented. 相似文献
85.
86.
David Hoff 《Journal of Mathematical Analysis and Applications》1982,86(1):221-236
We prove the existence of a large class of globally smooth solutions of the Cauchy problem for the system of n equations ut + Λ(x, t, u)ux = 0, where Λ is a diagonal matrix. We show that, under certain monotonicity conditions on both Λ and the initial data u0, the solution u will be locally Lipschitz continuous at positive times. Since u0 is a function of locally bounded variation, our result thus provides both for the smoothing of discontinuities in u0 as well as for the global preservation of smoothness. The global existence results from an a priori estimate of , which we obtain by a device which enables us to effectively uncouple the system of equations for . Finally, we prove a partial converse which demonstrates that our hypotheses are not overly restrictive. 相似文献
87.
Photolysis of C5H5Nb(CO)4 with excess cycloheptatriene gives the dark brown tetrahapto complex C5H5Nb(CO)2C7H8 but no C5H5NbC7H7 analogous to the corresponding reaction of C5H5V(CO)4 with cycloheptatriene. Photolysis of C5H5Nb(CO)4 with cyclooctatetraene gives the dark green tetrahapto complex C5H5Nb(CO)2C8H8, the C8H8 ring in this complex remains fluxional below -86° C. Reaction of C5H5Nb(CO)4 with I2 gives re-brown C5H5Nb(CO)3I2 in which the carbonyl groups are relatively labile. Thus reaction of C5H5Nb-(CO)3I2 with (CH3)2PCH2CH2P(CH3)2 under ambient conditions results in the rapid replacement of two CO groups to give C5H5Nb(CO)[(CH3)2PCH2CH2 -P(CH3)2]I2. Treatment of C5H5V(CO)4 with I2 at room temperature gives the carbonyl-free complex C5H5VI2 with no evidence for any cyclopentadienyl-vanadium carbonyl iodide intermediates. 相似文献
88.
89.
G. Hoff 《Colloid and polymer science》1962,181(1):71-73
Ohne Zusammenfassung 相似文献
90.
Envelopes of energy spectra of delayed neutrons from 8 precursors are calculated, taking into account transitions to excited states in the final nuclei. Theoretical branching ratios to these states are presented and compared with the few observed data available. 相似文献