全文获取类型
收费全文 | 221864篇 |
免费 | 5812篇 |
国内免费 | 3757篇 |
专业分类
化学 | 127983篇 |
晶体学 | 3621篇 |
力学 | 9138篇 |
综合类 | 238篇 |
数学 | 21818篇 |
物理学 | 68635篇 |
出版年
2020年 | 1949篇 |
2019年 | 2020篇 |
2018年 | 2032篇 |
2017年 | 1935篇 |
2016年 | 3355篇 |
2015年 | 2798篇 |
2014年 | 3705篇 |
2013年 | 9683篇 |
2012年 | 7428篇 |
2011年 | 9016篇 |
2010年 | 6115篇 |
2009年 | 6020篇 |
2008年 | 7839篇 |
2007年 | 7840篇 |
2006年 | 7394篇 |
2005年 | 6726篇 |
2004年 | 6005篇 |
2003年 | 5286篇 |
2002年 | 5156篇 |
2001年 | 6436篇 |
2000年 | 4945篇 |
1999年 | 4057篇 |
1998年 | 3218篇 |
1997年 | 3203篇 |
1996年 | 3179篇 |
1995年 | 2888篇 |
1994年 | 2747篇 |
1993年 | 2619篇 |
1992年 | 3090篇 |
1991年 | 2926篇 |
1990年 | 2833篇 |
1989年 | 2811篇 |
1988年 | 2732篇 |
1987年 | 2707篇 |
1986年 | 2534篇 |
1985年 | 3399篇 |
1984年 | 3370篇 |
1983年 | 2768篇 |
1982年 | 2967篇 |
1981年 | 2884篇 |
1980年 | 2798篇 |
1979年 | 2944篇 |
1978年 | 3173篇 |
1977年 | 2983篇 |
1976年 | 2922篇 |
1975年 | 2779篇 |
1974年 | 2734篇 |
1973年 | 2753篇 |
1967年 | 2137篇 |
1966年 | 1931篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Dr. Chen-Ming Lin Maritess Arancillo Jonathan Whisenant Prof. Kevin Burgess 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9484-9488
Secondary structures tend to be recognizable because they have repeating structural motifs, but mimicry of these does not have to follow such well-defined patterns. Bioinformatics studies to match side-chain orientations of a novel hydantoin triazole chemotype ( 1 ) to protein-protein interfaces revealed it tends to align well across parallel and antiparallel sheets, like rungs on a ladder. One set of these overlays was observed for the protein-protein interaction uPA⋅uPAR. Consequently, chemotype 1 was made with appropriate side-chains to mimic uPA at this interface. Biophysical assays indicate these compounds did in fact bind uPAR, and elicit cellular responses that affected invasion, migration, and wound healing. 相似文献
22.
23.
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
24.
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
25.
Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis Extracts by LC‐MS/MS
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
26.
27.
28.
An approach of dynamic mesh adaptation for simulating 3‐dimensional unsteady moving‐immersed‐boundary flows
下载免费PDF全文
![点击此处可从《国际流体数值方法杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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
29.
30.
Jie Lu Ju-Kang Wu Yao Jiang Dr. Peng Tan Lin Zhang Yu Lei Prof. Xiao-Qin Liu Prof. Lin-Bing Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(16):6490-6496
Hierarchically porous metal–organic frameworks (HP-MOFs) are promising in various applications. Most reported HP-MOFs are prepared based on the generation of mesopores in microporous frameworks, and the formed mesopores are connected by microporous channels, limiting the accessibility of mesopores for bulky molecules. A hierarchical structure is formed by constructing microporous MOFs in uninterrupted mesoporous tunnels. Using the confined space in as-prepared mesoporous silica, highly dispersed metal precursors for MOFs are coated on the internal surface of mesoporous tunnels. Ligand vapor-induced crystallization is employed to enable quantitative formation of MOFs in situ, in which sublimated ligands diffuse into mesoporous tunnels and react with metal precursors. The obtained hierarchically porous composites exhibit record-high adsorption capacity for the bulky molecule trypsin. The thermal and storage stability of trypsin is improved upon immobilization on the composites. 相似文献