全文获取类型
收费全文 | 228389篇 |
免费 | 8589篇 |
国内免费 | 4896篇 |
专业分类
化学 | 131812篇 |
晶体学 | 2929篇 |
力学 | 10156篇 |
综合类 | 289篇 |
数学 | 22678篇 |
物理学 | 74010篇 |
出版年
2021年 | 2111篇 |
2020年 | 2498篇 |
2019年 | 2476篇 |
2018年 | 2471篇 |
2017年 | 2316篇 |
2016年 | 3966篇 |
2015年 | 3342篇 |
2014年 | 4416篇 |
2013年 | 10382篇 |
2012年 | 8349篇 |
2011年 | 9867篇 |
2010年 | 6659篇 |
2009年 | 6571篇 |
2008年 | 8372篇 |
2007年 | 8293篇 |
2006年 | 7947篇 |
2005年 | 6981篇 |
2004年 | 6207篇 |
2003年 | 5473篇 |
2002年 | 5294篇 |
2001年 | 6522篇 |
2000年 | 5184篇 |
1999年 | 4290篇 |
1998年 | 3444篇 |
1997年 | 3442篇 |
1996年 | 3391篇 |
1995年 | 3122篇 |
1994年 | 2916篇 |
1993年 | 2702篇 |
1992年 | 3191篇 |
1991年 | 2982篇 |
1990年 | 2906篇 |
1989年 | 2751篇 |
1988年 | 2666篇 |
1987年 | 2636篇 |
1986年 | 2441篇 |
1985年 | 3331篇 |
1984年 | 3307篇 |
1983年 | 2680篇 |
1982年 | 2869篇 |
1981年 | 2805篇 |
1980年 | 2665篇 |
1979年 | 2831篇 |
1978年 | 3080篇 |
1977年 | 2896篇 |
1976年 | 2846篇 |
1975年 | 2697篇 |
1974年 | 2646篇 |
1973年 | 2675篇 |
1967年 | 2126篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Yanxia Xu Yanbing Lv Ruili Wu Huaibin Shen Huawei Yang Han Zhang Jinjie Li Lin Song Li 《Particle & Particle Systems Characterization》2020,37(3):1900441
Indium phosphide (InP) quantum dots (QDs) are ideal substitutes for widely used cadmium-based QDs and have great application prospects in biological fields due to their environmentally benign properties and human safety. However, the synthesis of InP core/shell QDs with biocompatibility, high quantum yield (QY), uniform particle size, and high stability is still a challenging subject. Herein, high quality (QY up to 72%) thick shell InP/GaP/ZnS core/shell QDs (12.8 ± 1.4 nm) are synthesized using multiple injections of shell precursor and extension of shell growth time, with GaP serving as the intermediate layer and 1-octanethiol acting as the new S source. The thick shell InP/GaP/ZnS core/shell QDs still keep high QY and photostability after transfer into water. InP/GaP/ZnS core/shell QDs as fluorescence labels to establish QD-based fluorescence-linked immunosorbent assay (QD-FLISA) for quantitative detection of C-reactive protein (CRP), and a calibration curve is established between fluorescence intensity and CRP concentrations (range: 1–800 ng mL−1, correlation coefficient: R2 = 0.9992). The limit of detection is 2.9 ng mL−1, which increases twofold compared to previously reported cadmium-free QD-based immunoassays. Thus, InP/GaP/ZnS core/shell QDs as a great promise fluorescence labeling material, provide a new route for cadmium-free sensitive and specific immunoassays in biomedical fields. 相似文献
33.
34.
The European Physical Journal Special Topics - The removal of suspended particles from the interior of a thermocapillary liquid bridge via a finite-particle-size effect restricting the particle... 相似文献
35.
We study the full counting statistics of transport electrons through a semiconductor two-level quantum dot with Rashba spin–orbit (SO) coupling, which acts as a nonabelian gauge field and thus induces the electron transition between two levels along with the spin flip. By means of the quantum master equation approach, shot noise and skewness are obtained at finite temperature with two-body Coulomb interaction. We particularly demonstrate the crucial effect of SO coupling on the super-Poissonian fluctuation of transport electrons, in terms of which the SO coupling can be probed by the zero-frequency cumulants. While the charge currents are not sensitive to the SO coupling. 相似文献
36.
37.
An approach of dynamic mesh adaptation for simulating 3‐dimensional unsteady moving‐immersed‐boundary flows 下载免费PDF全文
In this paper, we present an approach of dynamic mesh adaptation for simulating complex 3‐dimensional incompressible moving‐boundary flows by immersed boundary methods. Tetrahedral meshes are adapted by a hierarchical refining/coarsening algorithm. Regular refinement is accomplished by dividing 1 tetrahedron into 8 subcells, and irregular refinement is only for eliminating the hanging points. Merging the 8 subcells obtained by regular refinement, the mesh is coarsened. With hierarchical refining/coarsening, mesh adaptivity can be achieved by adjusting the mesh only 1 time for each adaptation period. The level difference between 2 neighboring cells never exceeds 1, and the geometrical quality of mesh does not degrade as the level of adaptive mesh increases. A predictor‐corrector scheme is introduced to eliminate the phase lag between adapted mesh and unsteady solution. The error caused by each solution transferring from the old mesh to the new adapted one is small because most of the nodes on the 2 meshes are coincident. An immersed boundary method named local domain‐free discretization is employed to solve the flow equations. Several numerical experiments have been conducted for 3‐dimensional incompressible moving‐boundary flows. By using the present approach, the number of mesh nodes is reduced greatly while the accuracy of solution can be preserved. 相似文献
38.
Nonlinear Dynamics - With an increasing number of people sharing feelings and opinions online, the online platforms have become one of the most important channels for public opinion dissemination.... 相似文献
39.
40.