全文获取类型
收费全文 | 705973篇 |
免费 | 15626篇 |
国内免费 | 3896篇 |
专业分类
化学 | 386411篇 |
晶体学 | 9771篇 |
力学 | 32692篇 |
综合类 | 78篇 |
数学 | 91603篇 |
物理学 | 204940篇 |
出版年
2021年 | 6184篇 |
2020年 | 7755篇 |
2019年 | 9642篇 |
2018年 | 10746篇 |
2017年 | 10526篇 |
2016年 | 16955篇 |
2015年 | 11063篇 |
2014年 | 15806篇 |
2013年 | 33493篇 |
2012年 | 26411篇 |
2011年 | 30388篇 |
2010年 | 23367篇 |
2009年 | 23055篇 |
2008年 | 28924篇 |
2007年 | 28188篇 |
2006年 | 25765篇 |
2005年 | 23451篇 |
2004年 | 21406篇 |
2003年 | 19152篇 |
2002年 | 19566篇 |
2001年 | 19976篇 |
2000年 | 15667篇 |
1999年 | 11477篇 |
1998年 | 9638篇 |
1997年 | 9469篇 |
1996年 | 9004篇 |
1995年 | 8064篇 |
1994年 | 8136篇 |
1993年 | 7803篇 |
1992年 | 8324篇 |
1991年 | 8717篇 |
1990年 | 8293篇 |
1989年 | 8148篇 |
1988年 | 7936篇 |
1987年 | 7645篇 |
1986年 | 7408篇 |
1985年 | 9618篇 |
1984年 | 9979篇 |
1983年 | 8363篇 |
1982年 | 8781篇 |
1981年 | 8222篇 |
1980年 | 7796篇 |
1979年 | 8308篇 |
1978年 | 8679篇 |
1977年 | 8583篇 |
1976年 | 8573篇 |
1975年 | 8118篇 |
1974年 | 8024篇 |
1973年 | 8349篇 |
1972年 | 6181篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
81.
82.
Nonlinear Dynamics - In this paper, we analyze the effect which the choice of a friction model has on tippe top inversion in the case where the resulting action of all dissipative forces is... 相似文献
83.
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
84.
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
85.
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
86.
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
87.
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88.
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
89.
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
90.
Corinne Rondeau-Mouro Mireille Cambert Laurent Blondel Yves Diascorn Léo Mbaya Nor Nadiah Binti Ahmad Nazari Sarah Helary Tiphaine Lucas 《Magnetic resonance in chemistry : MRC》2022,60(7):678-691
A temperature control unit was implemented to vary the temperature of samples studied on a commercial Mobile Universal Surface Explorer nuclear magnetic resonance (MOUSE-NMR) apparatus. The device was miniaturized to fit the maximum MOUSE sampling depth (25 mm). It was constituted by a sample holder sandwiched between two heat exchangers placed below and above the sample. Air was chosen as the fluid to control the temperature at the bottom of the sample, at the interface between the NMR probe and the sample holder, in order to gain space. The upper surface of the sample was regulated by the circulation of water inside a second heat exchanger placed above the sample holder. The feasibility of using such a device was demonstrated first on pure water and then on several samples of bread dough with different water contents. For this, T1 relaxation times were measured at various temperatures and depths and were then compared with those acquired with a conventional compact closed-magnet spectrometer. Discussion of results was based on biochemical transformations in bread dough (starch gelatinization and gluten heat denaturation). It was demonstrated that, within a certain water level range, and because of the low magnetic field strength of the MOUSE, a linear relationship could be established between T1 relaxation times and the local temperature in the dough sample. 相似文献