全文获取类型
收费全文 | 1407267篇 |
免费 | 43671篇 |
国内免费 | 19212篇 |
专业分类
化学 | 716666篇 |
晶体学 | 21147篇 |
力学 | 79592篇 |
综合类 | 768篇 |
数学 | 251628篇 |
物理学 | 400349篇 |
出版年
2021年 | 16451篇 |
2020年 | 19006篇 |
2019年 | 19377篇 |
2018年 | 15001篇 |
2017年 | 13098篇 |
2016年 | 31457篇 |
2015年 | 24465篇 |
2014年 | 35252篇 |
2013年 | 80662篇 |
2012年 | 45003篇 |
2011年 | 41534篇 |
2010年 | 42141篇 |
2009年 | 44452篇 |
2008年 | 38793篇 |
2007年 | 33421篇 |
2006年 | 39835篇 |
2005年 | 31057篇 |
2004年 | 31814篇 |
2003年 | 29817篇 |
2002年 | 30742篇 |
2001年 | 30254篇 |
2000年 | 26270篇 |
1999年 | 24219篇 |
1998年 | 22545篇 |
1997年 | 22385篇 |
1996年 | 22458篇 |
1995年 | 20357篇 |
1994年 | 19696篇 |
1993年 | 18988篇 |
1992年 | 18936篇 |
1991年 | 19146篇 |
1990年 | 18284篇 |
1989年 | 18131篇 |
1988年 | 17617篇 |
1987年 | 17605篇 |
1986年 | 16475篇 |
1985年 | 22795篇 |
1984年 | 23992篇 |
1983年 | 20159篇 |
1982年 | 21729篇 |
1981年 | 20927篇 |
1980年 | 20237篇 |
1979年 | 20456篇 |
1978年 | 21735篇 |
1977年 | 21341篇 |
1976年 | 20994篇 |
1975年 | 19703篇 |
1974年 | 19362篇 |
1973年 | 19777篇 |
1972年 | 14297篇 |
排序方式: 共有10000条查询结果,搜索用时 796 毫秒
181.
Safaei Bezgabadi A. Zarandi M. Borhani Bolorizadeh M. A. 《Optical and Quantum Electronics》2021,53(3):1-20
Optical and Quantum Electronics - Classification of hyperspectral image (HSI) is widely used for the study of remotely sensed images. Convolutional Neural Networks (CNNs) are one of the most... 相似文献
182.
Zmushko V. V. Razin A. N. Sinelnikova A. A. 《Journal of Applied Mechanics and Technical Physics》2022,63(3):400-407
Journal of Applied Mechanics and Technical Physics - Turbulent mixing at interfaces of three-layer gas systems after shock-wave passage has been studied. The influence of the initial roughness of... 相似文献
183.
Radiophysics and Quantum Electronics - We find self-consistent stationary distributions of the electric field and plasma density in the process of ionization self-channeling of quasielectrostatic... 相似文献
184.
Ukrainian Mathematical Journal - We establish new criteria of compatibility for a linear system of equations (equivalent to the Kronecker–Capelli theorem) or inequalities (equivalent to the... 相似文献
185.
Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.
相似文献186.
Journal of Fourier Analysis and Applications - We develop a theory of Sobolev orthogonal polynomials on the Sierpiński gasket ( $$SG$$ ), which is a fractal set that can be viewed as a limit... 相似文献
187.
Physics of Atomic Nuclei - We have investigated the robustness of the spin-navigator based method for manipulating the beam polarization to bend magnet installation errors. Toward that end,... 相似文献
188.
Dzhun I. O. Babaitsev G. V. Kozin M. G. Romashkina I. L. Shanova E. I. Chechenin N. G. 《Physics of the Solid State》2021,63(6):825-831
Physics of the Solid State - The external factors which influence the ferromagnetic resonance (FMR) line width in bilayer (ferromagnet/antiferromagnet) exchange-biased systems are studied. The... 相似文献
189.
Donglei Wei Huili Li Chuanqing Yang Jianmin Fu Hou Chen Liangjiu Bai Wenxiang Wang Huawei Yang Lixia Yang Ying Liang 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1588-1594
Acridone as a new kind of visible light photocatalyst has been developed to catalyze metal free atom transfer radical polymerization (ATRP). The photocatalyst possess low excited state potential as can undergo an oxidative quenching pathway to initiate ATRP of vinyl monomers. Kinetic study and light on/off reaction demonstrate the “living”/controlled nature of the polymerization by light. Block copolymers can be achieved by using PMMA as macroinitiator to reinitiate polymerization of other vinyl monomers, which shows highly preserved Br chain-end functionality in the synthesized polymers. Moreover, the polymerization can be conducted under air atmosphere as most photocatalysts need anaerobic condition, which may give inspiration of further application of this kind of photocatalyst. 相似文献
190.
Chueshova A. G. Pavlova L. A. Peshcherova S. M. Nepomnyashchikh A. I. 《Crystallography Reports》2021,66(7):1206-1215
Crystallography Reports - The orientation of grains and the special boundaries formed by them in multicrystalline silicon has been studied by electron backscattered diffraction. It is found that... 相似文献