全文获取类型
收费全文 | 660094篇 |
免费 | 4668篇 |
国内免费 | 1507篇 |
专业分类
化学 | 320920篇 |
晶体学 | 9252篇 |
力学 | 35831篇 |
综合类 | 24篇 |
数学 | 97368篇 |
物理学 | 202874篇 |
出版年
2021年 | 5666篇 |
2020年 | 6126篇 |
2019年 | 6989篇 |
2018年 | 13444篇 |
2017年 | 13738篇 |
2016年 | 15080篇 |
2015年 | 7287篇 |
2014年 | 11877篇 |
2013年 | 26712篇 |
2012年 | 22912篇 |
2011年 | 31065篇 |
2010年 | 22169篇 |
2009年 | 22350篇 |
2008年 | 28678篇 |
2007年 | 30465篇 |
2006年 | 21217篇 |
2005年 | 21530篇 |
2004年 | 19016篇 |
2003年 | 17797篇 |
2002年 | 16780篇 |
2001年 | 17219篇 |
2000年 | 13407篇 |
1999年 | 10196篇 |
1998年 | 8892篇 |
1997年 | 8693篇 |
1996年 | 8234篇 |
1995年 | 7401篇 |
1994年 | 7346篇 |
1993年 | 7147篇 |
1992年 | 7508篇 |
1991年 | 8105篇 |
1990年 | 7739篇 |
1989年 | 7701篇 |
1988年 | 7481篇 |
1987年 | 7287篇 |
1986年 | 6975篇 |
1985年 | 8894篇 |
1984年 | 9214篇 |
1983年 | 7810篇 |
1982年 | 8089篇 |
1981年 | 7596篇 |
1980年 | 7161篇 |
1979年 | 7847篇 |
1978年 | 8147篇 |
1977年 | 8003篇 |
1976年 | 8026篇 |
1975年 | 7695篇 |
1974年 | 7483篇 |
1973年 | 7878篇 |
1972年 | 5847篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Structural characterisation of such bio-objects as fibrinogen solution, yeast cells, wheat seeds and bone tissues has been done using two versions of cryoporometry based on the integral Gibbs-Thomson (IGT) equation for freezing point depression of pore liquids and the measurements by 1H NMR spectroscopy (180-200 < T < 273 K) and the thermally stimulated depolarisation current (TSDC) method (90 < T < 273 K) of structured water. The IGT equation was solved using a self-consisting regularization procedure including the maximum entropy principle applied to the distribution function of pore size (PSD). Both methods give clear pictures of changes in the structural characteristics caused, e.g., by hydration and swelling of wheat seeds and yeast cells, coagulation and interaction of fibrinogen with solid nanoparticles in the aqueous media, and the human bone tissue disease. 相似文献
992.
B. M. Azizur Rahman A. K. M. Saiful Kabir Muttukrishnan Rajarajan Kenneth T. V. Grattan 《Optical and Quantum Electronics》2005,37(1-3):171-183
Modal solutions of planar photonic crystal waveguides with rectangular air-holes are presented by using a rigorous full-vectorial finite element-based approach. The effective indices, mode field profiles, spot-sizes, power confinements, modal hybridness, beat lengths and group velocity dispersions are shown for the fundamental and higher order modes of the quasi-TE and TM polarizations. 相似文献
993.
The results of the elemental analysis of blood serum are often used for the diagnosis of different diseases associated with derangements of mineral metabolism. In this work, we studied the main sources of a systematic error in the atomic-emission spectrometric (AES) analysis of blood serum and developed a procedure for the AES determination of Ca, Cu, Fe, Mg, P, and Zn in the human blood serum. The repeatability relative standard deviations of determinations varied from 10 to 24%. 相似文献
994.
995.
A. Di Maio A. Rocco P. Ferraro M. De Rosa P. De Natale S. De Nicola A. Finizio G. Pierattini G. Coppola M. Iodice V. Striano 《Optics and Lasers in Engineering》2007,45(3):385
In view of the growing interest for non-destructive tests of materials, geodynamical monitoring and in general remote sensing, there is a great effort to bring practical optical sensors from research labs to industrial and environmental applications. In this paper, we employ digital holographic technique as an efficient tool for evaluating the strain measurement capability of fiber Bragg gratings (FBG). A cantilever beam has been employed as a test structure under loading test. The strain measurements results obtained by fiber-based sensors have been compared to those obtained by using full-field digital holographic technique and point-wise strain gauge sensors glued on the same cantilever beam. A simple theoretical model is also presented to interpret and compare the experimental results coming from different techniques. 相似文献
996.
Kwang-Hua W. Chu 《International Journal of Theoretical Physics》2007,46(12):3230-3233
The modified Gross–Pitaevskii equation was derived and solved to obtain the 1D solution in the zero-energy limit. This stationary
solution could account for the dominated contributions due to the kinetic effect as well as the chemical potential in inhomogeneous
Bose gases. 相似文献
997.
A new approach to identify the independent amplitudes along with their partial wave multipole expansions, for photo-and electro-production
is suggested, which is generally applicable to mesons with arbitrary spin-parity. These amplitudes facilitate direct identification
of different resonance contributions.
相似文献
998.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献
999.
1000.