全文获取类型
收费全文 | 5784篇 |
免费 | 307篇 |
国内免费 | 155篇 |
专业分类
化学 | 4192篇 |
晶体学 | 52篇 |
力学 | 136篇 |
综合类 | 12篇 |
数学 | 768篇 |
物理学 | 1086篇 |
出版年
2023年 | 41篇 |
2022年 | 50篇 |
2021年 | 67篇 |
2020年 | 91篇 |
2019年 | 96篇 |
2018年 | 69篇 |
2017年 | 62篇 |
2016年 | 160篇 |
2015年 | 153篇 |
2014年 | 157篇 |
2013年 | 249篇 |
2012年 | 330篇 |
2011年 | 372篇 |
2010年 | 244篇 |
2009年 | 195篇 |
2008年 | 318篇 |
2007年 | 318篇 |
2006年 | 297篇 |
2005年 | 295篇 |
2004年 | 204篇 |
2003年 | 167篇 |
2002年 | 177篇 |
2001年 | 108篇 |
2000年 | 122篇 |
1999年 | 104篇 |
1998年 | 79篇 |
1997年 | 103篇 |
1996年 | 102篇 |
1995年 | 85篇 |
1994年 | 82篇 |
1993年 | 89篇 |
1992年 | 85篇 |
1991年 | 42篇 |
1990年 | 51篇 |
1989年 | 44篇 |
1988年 | 46篇 |
1987年 | 54篇 |
1986年 | 57篇 |
1985年 | 73篇 |
1984年 | 30篇 |
1983年 | 46篇 |
1982年 | 60篇 |
1980年 | 52篇 |
1979年 | 30篇 |
1978年 | 38篇 |
1977年 | 60篇 |
1976年 | 30篇 |
1975年 | 31篇 |
1972年 | 28篇 |
1971年 | 28篇 |
排序方式: 共有6246条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Marko D. Mihovilovic Bernhard Müller Markus Spina Arjumand I. Durrani Peter Stanetty Georg Dazinger Karl Kirchner 《Monatshefte für Chemie / Chemical Monthly》2006,137(6):785-794
Summary. Recombinant Escherichia coli overexpressing Pseudomonas sp. NCIMB 9872 cyclopentanone monooxygenase (CPMO, EC 1.14.13.16) and Acinetobacter sp. NCIMB 9871 cyclohexanone monooxygenase (CHMO, EC 1.14.13.22) have been utilized in whole-cell Baeyer-Villiger biotransformations of prochiral bicycloketones. A significant difference in substrate acceptance and stereoselectivity was
observed for bicyclo[3.3.0] and bicyclo[4.3.0] substrates. A plausible mechanism of these transformations was established
by means of high level DFT/B3LYP calculations suggesting an essential difference in electronic requirements for a successful
enzymatic conversion, which was similarly encountered in recombinant whole-cell mediated biooxidations. Some of the lactones
produced in the biocatalytic Baeyer-Villiger oxidation represent key intermediates for the synthesis of indole alkaloids. 相似文献
25.
A. Loidl A. Krimmel K. Knorr G. Sparn M. Lang C. Geibel S. Horn A. Grauel F. Steglich B. Welslau N. Grewe H. Nakotte F. R. de Boer A. P. Murani 《Annalen der Physik》1992,504(2):78-91
Elastic and inelastic neutron-scattering studies on the system Ce(Cu1?xNix)2Ge2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high-field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T-x phase diagram consisting of two different antiferromagnetic phases for x < 0.2 and 0.2 < x < 0.75, respectively, and a heavy-Fermi-liquid regime at higher Ni concentrations. The experimental results are interpreted in terms of an alloying-induced transition from local-moment to itinerant heavy-fermion magnetism. Fingerprints of this latter phase are a strongly reduced ordered moment and a short incommensurate ordering wave vector, in accord with theoretical predictions. A surprisingly good agreement between theory and experiment is found for x > 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line-shape analysis of the quasielastic neutron-scattering intensity, from magnetization and thermopower experiments. 相似文献
26.
Ahilleas N. Maurellis Rüdiger Lang Jochen Landgraf 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(3):295-323
The computation of radiation transmittance in nongray, inhomogeneous atmospheric models is frequently complicated by complex bands of line spectra which range in value over many orders of magnitudes and depend strongly on either or both of pressure and temperature. We present here a new opacity sampling technique which is shown to determine correctly the wavelength-averaged extinction due to path-dependent realizations of banded line spectra. The technique is easy to implement computationally and is applicable to a wide variety of atmospheric problems in which frequent iteration of the radiative transfer model is required. We consider two such instances: modeling of solar flux attenuation for use in a time-dependent planetary ionosphere model and retrieval from nadir measurements of backscattered solar irradiance. The power of the new method lies in its straightforward analytical treatment of both atmospheric inhomogeneity and spectral complexity. It is thus relevant for both retrieval and radiative transfer modeling purposes. 相似文献
27.
3rd International Conference on Trace Element Speciation in Biomedical, Nutritional and Environmental Sciences 相似文献
28.
Vladimir B. Arion Alexey A. Nazarov Christian G. Hartinger Gerald Giester Bernhard K. Keppler 《应用有机金属化学》2003,17(9):723-724
For the unsymmetrical title compound, 1‐bromo‐1′‐[(2S)‐N‐(1‐hydroxy‐3‐methylbutane‐2‐yl)]‐ferroceneamide, two independent molecules were found in the asymmetric unit. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
29.
30.
Urs Lang 《Mathematische Zeitschrift》1992,210(1):581-592