全文获取类型
收费全文 | 507626篇 |
免费 | 4100篇 |
国内免费 | 1851篇 |
专业分类
化学 | 255005篇 |
晶体学 | 7322篇 |
力学 | 24352篇 |
综合类 | 21篇 |
数学 | 81250篇 |
物理学 | 145627篇 |
出版年
2021年 | 3306篇 |
2020年 | 3693篇 |
2019年 | 4327篇 |
2018年 | 15615篇 |
2017年 | 15422篇 |
2016年 | 14070篇 |
2015年 | 5763篇 |
2014年 | 8117篇 |
2013年 | 20199篇 |
2012年 | 18213篇 |
2011年 | 27570篇 |
2010年 | 18032篇 |
2009年 | 18182篇 |
2008年 | 22754篇 |
2007年 | 24873篇 |
2006年 | 15691篇 |
2005年 | 15131篇 |
2004年 | 13787篇 |
2003年 | 12823篇 |
2002年 | 11782篇 |
2001年 | 12192篇 |
2000年 | 9748篇 |
1999年 | 7291篇 |
1998年 | 6409篇 |
1997年 | 6405篇 |
1996年 | 5852篇 |
1995年 | 5146篇 |
1994年 | 5004篇 |
1993年 | 5087篇 |
1992年 | 5446篇 |
1991年 | 5555篇 |
1990年 | 5274篇 |
1989年 | 5240篇 |
1988年 | 5228篇 |
1987年 | 5053篇 |
1986年 | 4856篇 |
1985年 | 6482篇 |
1984年 | 6771篇 |
1983年 | 5547篇 |
1982年 | 6070篇 |
1981年 | 5868篇 |
1980年 | 5573篇 |
1979年 | 5817篇 |
1978年 | 6111篇 |
1977年 | 5972篇 |
1976年 | 6154篇 |
1975年 | 5624篇 |
1974年 | 5682篇 |
1973年 | 6147篇 |
1972年 | 3967篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
A. E. Zernov 《Ukrainian Mathematical Journal》1991,43(6):705-709
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 6, pp. 755–760, June, 1991. 相似文献
162.
H. Glatzel R. Schneider T. Fauster V. Dose 《Zeitschrift für Physik B Condensed Matter》1992,88(1):53-61
Inverse photoemission spectra were taken for thin epitaxial iron films on Cu(100). For a film thickness of eight monolayers the observed electronic states are characteristic for a fcc(100) surface. Thed-bands of iron show a ferromagnetic exchange splitting of 1.1 eV, considerably smaller than the bulk value of 1.8 eV, which we observe for film thicknesses above 18 monolayers. 相似文献
163.
164.
165.
A technique is proposed for improving the accuracy of the heat of fusion of semicrystalline polymers by DSC. The results of three commercially available instruments are compared. 相似文献
166.
Summary X-ray reflectivity may be used to determine the internal structure of thin polymer films. An electron density difference of 10% for polystyrene and polyisoprene is sufficient to distinguish between a random distribution of lamellae, complete orientation parallel to the substrate surface and a surface induced formation of lamellae. The disappearance of the lamellar Bragg-peaks, with heating of the film, shows the transition into the disordered state. 相似文献
167.
168.
169.
170.
A combined-modality treatment program consisting of botulinum toxin injection (Botox) and voice therapy was used to treat 17 subjects diagnosed with adductor spasmodic dysphonia (ADD SD). Ten subjects with ADD SD served as the control and were given Botox only. Voice therapy after Botox injection was directed toward reducing the hyperfunctional vocal behaviors, primarily glottal overpressure at voice onset and anterior-posterior squeezing. The results indicated that subjects who underwent combined-modality treatment maintained significantly higher mean airflow rates for significantly longer periods. Moreover, there was a carryover effect in these patients when they received Botox only. Adductor spasmodic dysphonia is treated most effectively when intrinsic laryngeal muscle spasms are reduced or eliminated by Botox injection and extrinsic hyperfunctional vocal behaviors are treated with voice therapy 相似文献