全文获取类型
收费全文 | 98482篇 |
免费 | 12426篇 |
国内免费 | 9388篇 |
专业分类
化学 | 51241篇 |
晶体学 | 794篇 |
力学 | 4165篇 |
综合类 | 516篇 |
数学 | 9071篇 |
物理学 | 25591篇 |
无线电 | 28918篇 |
出版年
2024年 | 308篇 |
2023年 | 1980篇 |
2022年 | 2524篇 |
2021年 | 3256篇 |
2020年 | 3158篇 |
2019年 | 3004篇 |
2018年 | 2590篇 |
2017年 | 2576篇 |
2016年 | 3593篇 |
2015年 | 3944篇 |
2014年 | 4759篇 |
2013年 | 6192篇 |
2012年 | 7525篇 |
2011年 | 7697篇 |
2010年 | 5615篇 |
2009年 | 5707篇 |
2008年 | 6163篇 |
2007年 | 5734篇 |
2006年 | 5305篇 |
2005年 | 4704篇 |
2004年 | 3640篇 |
2003年 | 3012篇 |
2002年 | 2798篇 |
2001年 | 2401篇 |
2000年 | 2211篇 |
1999年 | 2271篇 |
1998年 | 1996篇 |
1997年 | 1826篇 |
1996年 | 1842篇 |
1995年 | 1617篇 |
1994年 | 1479篇 |
1993年 | 1293篇 |
1992年 | 1204篇 |
1991年 | 1007篇 |
1990年 | 865篇 |
1989年 | 617篇 |
1988年 | 540篇 |
1987年 | 437篇 |
1986年 | 368篇 |
1985年 | 431篇 |
1984年 | 328篇 |
1983年 | 257篇 |
1982年 | 224篇 |
1981年 | 155篇 |
1980年 | 143篇 |
1979年 | 124篇 |
1978年 | 109篇 |
1976年 | 109篇 |
1975年 | 97篇 |
1974年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
21.
22.
Nonlinear Dynamics - Epilepsy is the second largest neurological disease which seriously threatens human life and health. The one important reason of inducing epileptic seizures is ischemic stroke... 相似文献
23.
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
24.
Rongrong Li Hongjie Peng Qingping Wu Xuejun Zhou Jiang He Hangjia Shen Minghui Yang Chilin Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):12227-12236
Herein, we propose the construction of a sandwich-structured host filled with continuous 2D catalysis–conduction interfaces. This MoN-C-MoN trilayer architecture causes the strong conformal adsorption of S/Li2Sx and its high-efficiency conversion on the two-sided nitride polar surfaces, which are supplied with high-flux electron transfer from the buried carbon interlayer. The 3D self-assembly of these 2D sandwich structures further reinforces the interconnection of conductive and catalytic networks. The maximized exposure of adsorptive/catalytic planes endows the MoN-C@S electrode with excellent cycling stability and high rate performance even under high S loading and low host surface area. The high conductivity of this trilayer texture does not compromise the capacity retention after the S content is increased. Such a job-synergistic mode between catalytic and conductive functions guarantees the homogeneous deposition of S/Li2Sx, and avoids thick and devitalized accumulation (electrode passivation) even after high-rate and long-term cycling. 相似文献
25.
We consider concentrated vorticities for the Euler equation on a smooth domain in the form of supported on well-separated vortical domains , , of small diameters . A conformal mapping framework is set up to study this free boundary problem with being part of unknowns. For any given vorticities and small , through a perturbation approach, we obtain such piecewise constant steady vortex patches as well as piecewise smooth Lipschitz steady vorticities, both concentrated near non-degenerate critical configurations of the Kirchhoff–Routh Hamiltonian function. When vortex patch evolution is considered as the boundary dynamics of , through an invariant subspace decomposition, it is also proved that the spectral/linear stability of such steady vortex patches is largely determined by that of the 2N-dimensional linearized point vortex dynamics, while the motion is highly oscillatory in the 2N-codim directions corresponding to the vortical domain shapes. 相似文献
26.
27.
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)
28.
针对传统低压回路电阻测试仪只能在被测设备停电时使用的一大限制,本文提出并设计了一种新型低压回路电阻测试仪。该仪器可在低压设备运行状态下对其回路电阻进行测量,在保证测量精度的前提下减少了设备停电率,大大提高了工作效率。 相似文献
29.
30.