全文获取类型
收费全文 | 460622篇 |
免费 | 4350篇 |
国内免费 | 1345篇 |
专业分类
化学 | 236558篇 |
晶体学 | 7397篇 |
力学 | 21806篇 |
综合类 | 9篇 |
数学 | 54631篇 |
物理学 | 145916篇 |
出版年
2020年 | 3506篇 |
2019年 | 3970篇 |
2018年 | 5998篇 |
2017年 | 6021篇 |
2016年 | 7961篇 |
2015年 | 4834篇 |
2014年 | 7638篇 |
2013年 | 19178篇 |
2012年 | 14813篇 |
2011年 | 17740篇 |
2010年 | 12592篇 |
2009年 | 12475篇 |
2008年 | 16278篇 |
2007年 | 16378篇 |
2006年 | 15435篇 |
2005年 | 16209篇 |
2004年 | 15096篇 |
2003年 | 12759篇 |
2002年 | 11471篇 |
2001年 | 12768篇 |
2000年 | 9833篇 |
1999年 | 7658篇 |
1998年 | 6694篇 |
1997年 | 6538篇 |
1996年 | 6228篇 |
1995年 | 5719篇 |
1994年 | 5802篇 |
1993年 | 5621篇 |
1992年 | 6103篇 |
1991年 | 6265篇 |
1990年 | 5995篇 |
1989年 | 5803篇 |
1988年 | 5929篇 |
1987年 | 5706篇 |
1986年 | 5390篇 |
1985年 | 7350篇 |
1984年 | 7675篇 |
1983年 | 6368篇 |
1982年 | 6629篇 |
1981年 | 6534篇 |
1980年 | 6419篇 |
1979年 | 6500篇 |
1978年 | 6879篇 |
1977年 | 6687篇 |
1976年 | 6851篇 |
1975年 | 6323篇 |
1974年 | 6352篇 |
1973年 | 6527篇 |
1972年 | 4585篇 |
1971年 | 3843篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
N. Raju T. Špaček J. Ježek I. M. Caminiti F. Leinisch K. Hideg P. Ježek W. E. Trommer 《Applied magnetic resonance》2006,30(3-4):373-383
Electron paramagnetic resonance (EPR) spectroscopy of spin-labeled fatty acids was used to investigate their interaction withEscherichia coli-expressed human mitochondrial uncoupling protein UCP2 refolded from inclusion bodies in nonaethylene glycol monododecyl ether (C12E9) micelles. 5-DOXYL-stearic acid and 4-PROXYL-palmitic acid bound to UCP2 exhibited additional clearly separated h+1I, h?1I “immobile” peaks in the low- and high-field region, respectively, separated by 42 and 44 Gauss, and extensively reduced h+1M, h?1M “mobile” peaks, separated by about 30 G, whereas with 7-DOXYL-stearic acid the I and M peaks were smoothed together into one wide peak. Competition of 4-PROXYL-palmitic acid with added palmitic acid, arachidonic acid, and all-cis-8,11,14-eicosatrienoic acid and of 7-DOXYL-stearic acid with arachidonic acid was indicated by the disappearance of the h+1I, h?1I “immobile” peaks, whereas redistribution in micelles without protein was indicated by the rising of the h+1M, h?1M “mobile” peaks. In conclusion, a competition of palmitic, arachidonic, and eicosatrienoic acid within a putative fatty acid binding site was observed for mitochondrial uncoupling protein UCP2. This finding together with the observation of EPR spectra of highly immobilized probes exclusively in the presence of the recombinant UCP2 suggest the existence of a fatty acid binding site on UCP2 which is a prerequisite of the fatty acid cycling mechanism as previously postulated for UCP1. 相似文献
992.
993.
994.
P Rabindra Reddy P R Prasad Reddy M Harilatha Reddy 《Journal of Chemical Sciences》1987,99(5-6):297-303
Studies on interaction of La(III), Pr(III), Nd(III), Sm(III), Gd(III), Dy(III) and Er(III) with inosine and xanthosine in
a 1:1 ratio have been carried out by potentiometric equilibrium measurements at 35±0·1°C and 0·1 M (KNO3) ionic strength. Investigations were also made for the interaction of these metal ions and nucleosides with the biologically
important secondary ligands glycine and histidine. These investigations were undertaken with a view to assess the influence
of charge on the structure and stability of 1:1 metal-inosine/xanthosine systems.
DBT/India overseas Fellow at Harvard University (1986–88). 相似文献
995.
996.
Mustafa Çelebier Ertan Şahin Nilgün Ancın Nurşen Altuntaş Öztaş Selma Gül Öztaş 《应用有机金属化学》2007,21(10):viii-viii
The article referenced above was first published online on 30 August 2007 with incorrect pagination; the pagination has now been corrected online and in print. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
997.
We investigate the existence and stability of solutions for higher-order two-point boundary value problems in case the differential
operator is not necessarily positive definite, i.e. with superlinear nonlinearities. We write an abstract realization of the
Dirichlet problem and provide abstract existence and stability results which are further applied to concrete problems. 相似文献
998.
C. P. Massarolo G. P. Menzala A. F. Pazoto 《Mathematical Methods in the Applied Sciences》2007,30(12):1419-1435
The aim of this work is to consider the Korteweg–de Vries equation in a finite interval with a very weak localized dissipation namely the H?1‐norm. Our main result says that the total energy decays locally uniform at an exponential rate. Our analysis improves earlier works on the subject (Q. Appl. Math. 2002; LX (1):111–129; ESAIM Control Optim. Calculus Variations 2005; 11 (3):473–486) and gives a satisfactory answer to a problem suggested in (Q. Appl. Math. 2002; LX (1):111–129). Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
999.
P. De Maesschalck 《Journal of Differential Equations》2007,238(2):338-365
By applying geometric techniques to real analytic singularly perturbed vector fields on the plane, we develop a way to give a bound on the Gevrey type of the Taylor development of canard manifolds at degenerate planar turning points. By blowing up the phase space at the turning point, we find asymptotic estimates even when such expansions w.r.t. traditional phase space variables do not exist. The asymptotic estimates are then used to give a sufficient and necessary condition on the existence of (local) canard solutions. 相似文献
1000.
L. E. Payne G. A. Philippin V. Proytcheva 《Mathematical Methods in the Applied Sciences》2007,30(15):1885-1898
In this paper, we investigate the continuous dependence on the geometry and the initial time for solutions u( x , t) of a class of nonlinear parabolic initial‐boundary value problems. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献