全文获取类型
收费全文 | 1306篇 |
免费 | 34篇 |
国内免费 | 2篇 |
专业分类
化学 | 883篇 |
晶体学 | 4篇 |
力学 | 60篇 |
数学 | 199篇 |
物理学 | 196篇 |
出版年
2023年 | 10篇 |
2022年 | 36篇 |
2021年 | 28篇 |
2020年 | 23篇 |
2019年 | 30篇 |
2018年 | 20篇 |
2017年 | 24篇 |
2016年 | 47篇 |
2015年 | 35篇 |
2014年 | 32篇 |
2013年 | 91篇 |
2012年 | 68篇 |
2011年 | 82篇 |
2010年 | 51篇 |
2009年 | 49篇 |
2008年 | 71篇 |
2007年 | 70篇 |
2006年 | 70篇 |
2005年 | 60篇 |
2004年 | 42篇 |
2003年 | 46篇 |
2002年 | 44篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1974年 | 6篇 |
1968年 | 4篇 |
排序方式: 共有1342条查询结果,搜索用时 15 毫秒
101.
102.
We numerically study properties of the dynamics of vortices in nonrotating Bose-Einstein condensates in the Thomas-Fermi regime. On the one hand, we compute the vortex energy as a function of its position and we predict, using the expression of the Magnus force, the vortex precession velocity. On the other hand, we calculate the temporal evolution of the vortex-state and test the accuracy of the previous prediction. We also investigate the validity of analytical formulae of this velocity involving the healing length. In addition, we analyze the velocity field and the angular momentum and we compare them to available analytical expressions. 相似文献
103.
Vincenzo Cunsolo Elisa Cairone Rosaria Saletti Vera Muccilli Salvatore Foti 《Rapid communications in mass spectrometry : RCM》2009,23(13):1907-1916
Two coeluting components, with experimentally measured Mr values of 25529 and 24606 Da, were identified by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and mass spectrometric analysis in the dephosphorylated casein fraction of a milk sample collected from an individual donkey belonging to the Ragusano breed of the east of Sicily. By coupling enzymatic digestions, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and RP‐HPLC/nano‐electrospray ionization tandem mass spectrometry (nESI‐MS/MS) analysis, the two proteins were identified as donkey β‐CNs and their sequences characterized completely, using the two known β‐CNs from mare as references. The two donkey β‐CNs, showing a mass difference of 923 Da, differ by the presence of the domain E27SITHINK34 in the full‐length component (Mr 25529 Da). In comparison with the mare's β‐CNs used as reference, they present nine amino acid substitutions: L→S37, R→H52, S→N81, P→V84, L→V91, R→Q203, P→L/I206, L→F210 and A→P219. Together, these substitutions account for the increase of 18 Da in the Mr of the donkey β‐CNs with respect to the counterparts from the mare. The molecular mass determination by ESI‐MS for the phosphorylated proteins showed that the full‐length component was composed of highly multi‐phosphorylated isoforms with five to seven phosphate groups. By analogy with the homologous mare's β‐CNs, the full‐length (226 amino acids) β‐CN was termed variant A, whereas the shorter (218 amino acids) β‐CN was termed variant AΔ5. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
104.
Salvatore Capozziello Giuseppe Basini Mariafelicia De Laurentis 《The European Physical Journal C - Particles and Fields》2011,71(6):1679
We derive a geometrical approach to produce the mass of particles that could be suitably tested at LHC. Starting from a 5D
unification scheme, we show that all the known interactions could be suitably deduced as an induced symmetry breaking of the
non-unitary GL(4)-group of diffeomorphisms. The deformations inducing such a breaking act as vector bosons that, depending on the gravitational
mass states, can assume the role of interaction bosons like gluons, electroweak bosons or photon. The further gravitational
degrees of freedom, emerging from the reduction mechanism in 4D, eliminate the hierarchy problem since generate a cutoff comparable
with electroweak one at TeV scales. In this “economic” scheme, gravity should induce the other interactions in a non-perturbative
way. 相似文献
105.
106.
107.
108.
Joann Huber Robert G.K. Donald Sang Ho Lee Lisa Wang Jarantow Michael J. Salvatore Xin Meng Ronald Painter Russell H. Onishi James Occi Karen Dorso Katherine Young Young Whan Park Stephen Skwish Michael J. Szymonifka Tim S. Waddell Lynn Miesel John W. Phillips Terry Roemer 《Chemistry & biology》2009,16(8):837-848
109.
110.
Enzo Cadoni Massimiliano Arca Claudia Fattuoni Maria G. Cabiddu Salvatore Cabiddu 《Tetrahedron》2008,64(27):6349-6357
The sulfinyl carbanion derived from 2,3-dihydro-1-benzothiophene-1-oxide and its lithium salt has been investigated by DFT calculations. The lithium carbanion was treated with aldehydes and imines to give chiral hydroxy and amino derivatives, with high stereoselectivity at the carbon α to the sulfoxide group (trans diastereoisomers), but with low diastereoselectivity at the hydroxyl or amine group. DFT calculations were used to rationalize the different stereochemical behavior of cyclic and acyclic lithiated sulfoxides in the reaction with aldehydes and azomethines. 相似文献