全文获取类型
收费全文 | 6237篇 |
免费 | 208篇 |
国内免费 | 99篇 |
专业分类
化学 | 3152篇 |
晶体学 | 23篇 |
力学 | 50篇 |
综合类 | 39篇 |
数学 | 2716篇 |
物理学 | 564篇 |
出版年
2024年 | 12篇 |
2023年 | 48篇 |
2022年 | 73篇 |
2021年 | 61篇 |
2020年 | 242篇 |
2019年 | 417篇 |
2018年 | 163篇 |
2017年 | 372篇 |
2016年 | 142篇 |
2015年 | 156篇 |
2014年 | 186篇 |
2013年 | 301篇 |
2012年 | 217篇 |
2011年 | 302篇 |
2010年 | 212篇 |
2009年 | 352篇 |
2008年 | 375篇 |
2007年 | 331篇 |
2006年 | 320篇 |
2005年 | 242篇 |
2004年 | 254篇 |
2003年 | 248篇 |
2002年 | 214篇 |
2001年 | 196篇 |
2000年 | 148篇 |
1999年 | 140篇 |
1998年 | 109篇 |
1997年 | 123篇 |
1996年 | 89篇 |
1995年 | 50篇 |
1994年 | 47篇 |
1993年 | 44篇 |
1992年 | 32篇 |
1991年 | 30篇 |
1990年 | 23篇 |
1989年 | 21篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 15篇 |
1985年 | 29篇 |
1984年 | 26篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 23篇 |
1977年 | 18篇 |
1976年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有6544条查询结果,搜索用时 31 毫秒
161.
A qualitative discussion on atom-surface elastic scattering taking place in the presence of laser radiation is given. It is suggested that appreciable effects of laser radiation on diffraction patterns may be expected if the laser radiation is capable of inducing electronic transitions in atoms with a large probability.Research sponsored by the Air Force Office of Scientific Research (AFSC), United States Air Force, under Contract No. F49620-78-C-0005, and the National Science Foundation under Grant No. CHE77-27826. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.Alfred P. Sloan Research Fellow, 1976–1980; Camille and Henry Dreyfus Teacher-Scholar, 1975–1980. 相似文献
162.
The phases occurring in samples of gross composition BaxWO3 (0.01 < x < 0.33) heated at temperatures between 1073 and 1373°K have been determined using X-ray diffraction and electron microscopy. At all temperatures a tetragonal tungsten bronze phase with a narrow homogeneity range of x = 0.20?0.21 was observed to form. In addition, at temperatures up to 1273°K, a series of orthorhombic intergrowth bronzes forms within a restricted composition range around x = 0.04. The latter phases are unstable at higher temperatures and were not found in preparations made at 1323°K. Similarly a new type of bronze phase forms at x = 0.14?0.16 at temperatures up to 1323°K, but not at 1373°K. The structure of this phase is unknown. Aspects of the crystal chemistry of the barium bronzes and the relationships to other bronze phases are discussed. 相似文献
163.
164.
165.
166.
167.
C. Yaicle F. Fauth R. Retoux M. Hervieu A. Maignan 《Journal of solid state chemistry》2005,178(5):1652-1660
Combining low-temperature electron (ED) and synchrotron powder diffraction (SPD) techniques, we have precisely determined the phase-separated crystal structure of Pr0.5Ca0.5Mn0.97Ga0.03O3. We demonstrate that the phase separation is associated with the onset of charge/orbital ordering at ∼230 K and that two ordered phases coexist at low temperature. In order to account for the significant anisotropic linewidth broadening observed in the SPD patterns, we had to include a specific strain model in the refinements. One of the phases, the most severely strained, is suggested to result from an imperfect charge ordering. 相似文献
168.
The reaction of decacarbonyldimanganese Mu2(CO)10 (1) With thallium(t) 3,6-di-tert-butyl-o-benzosemiquinolate (2) in solution was studied by ESR spectroscopy. Irradiation of solutions containing1 and2 in organic solvents with visible light at 220–280 K leads totrinuclear MnTlMn complex (3). An analysis of hyperfine structure parameters indicates that3 is a semiquinone complex of thallium. A possible mechanism of the formation of complex3 and its molecular structure was discussed.Translated fromIzveshya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 95–98, January, 1996. 相似文献
169.
170.