全文获取类型
收费全文 | 83724篇 |
免费 | 1670篇 |
国内免费 | 1462篇 |
专业分类
化学 | 28794篇 |
晶体学 | 956篇 |
力学 | 7099篇 |
综合类 | 67篇 |
数学 | 32576篇 |
物理学 | 17364篇 |
出版年
2023年 | 219篇 |
2022年 | 382篇 |
2021年 | 330篇 |
2020年 | 392篇 |
2019年 | 370篇 |
2018年 | 10678篇 |
2017年 | 10465篇 |
2016年 | 6352篇 |
2015年 | 1213篇 |
2014年 | 676篇 |
2013年 | 780篇 |
2012年 | 4344篇 |
2011年 | 10986篇 |
2010年 | 5962篇 |
2009年 | 6376篇 |
2008年 | 6965篇 |
2007年 | 9096篇 |
2006年 | 516篇 |
2005年 | 1570篇 |
2004年 | 1697篇 |
2003年 | 2134篇 |
2002年 | 1181篇 |
2001年 | 399篇 |
2000年 | 427篇 |
1999年 | 268篇 |
1998年 | 274篇 |
1997年 | 219篇 |
1996年 | 284篇 |
1995年 | 180篇 |
1994年 | 129篇 |
1993年 | 140篇 |
1992年 | 92篇 |
1991年 | 89篇 |
1990年 | 80篇 |
1989年 | 77篇 |
1988年 | 72篇 |
1987年 | 69篇 |
1986年 | 69篇 |
1985年 | 57篇 |
1984年 | 52篇 |
1983年 | 50篇 |
1982年 | 46篇 |
1981年 | 40篇 |
1980年 | 47篇 |
1979年 | 48篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications. 相似文献
2.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
3.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
4.
5.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
6.
7.
8.
9.
Hierarchical motion planning at the acceleration level based on task priority matrix for space robot
Nonlinear Dynamics - A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge is to... 相似文献
10.
S. V. Panin I. V. Vlasov V. P. Sergeev B. B. Ovechkin P. O. Marushchak Sunder Ramasubbu P. S. Lyubutin V. V. Titkov 《Physical Mesomechanics》2015,18(3):261-272
The structure and properties of 12Cr1MoV steel irradiated with a zirconium ion beam were studied by optical microscopy, scanning electron microscopy, and micro- and nanoindentation. It is shown that the modification covers the entire cross-section of the irradiated specimens to a depth of 1 mm. The data on irradiation-induced structural changes are used to interpret the changes in mechanical properties of the irradiated specimens under static and cyclic loading. Particular attention is given to analysis of strain estimation by the digital image correlation method. 相似文献