全文获取类型
收费全文 | 104822篇 |
免费 | 4824篇 |
国内免费 | 5164篇 |
专业分类
化学 | 46221篇 |
晶体学 | 1292篇 |
力学 | 7787篇 |
综合类 | 352篇 |
数学 | 34550篇 |
物理学 | 24608篇 |
出版年
2024年 | 85篇 |
2023年 | 482篇 |
2022年 | 1057篇 |
2021年 | 1045篇 |
2020年 | 1098篇 |
2019年 | 1171篇 |
2018年 | 11207篇 |
2017年 | 11151篇 |
2016年 | 7323篇 |
2015年 | 2353篇 |
2014年 | 2171篇 |
2013年 | 2620篇 |
2012年 | 6460篇 |
2011年 | 13128篇 |
2010年 | 7669篇 |
2009年 | 7927篇 |
2008年 | 8723篇 |
2007年 | 10568篇 |
2006年 | 1983篇 |
2005年 | 2662篇 |
2004年 | 2550篇 |
2003年 | 2784篇 |
2002年 | 1955篇 |
2001年 | 1004篇 |
2000年 | 824篇 |
1999年 | 621篇 |
1998年 | 504篇 |
1997年 | 377篇 |
1996年 | 396篇 |
1995年 | 285篇 |
1994年 | 206篇 |
1993年 | 231篇 |
1992年 | 155篇 |
1991年 | 167篇 |
1990年 | 106篇 |
1989年 | 133篇 |
1988年 | 91篇 |
1987年 | 108篇 |
1986年 | 96篇 |
1985年 | 81篇 |
1984年 | 59篇 |
1983年 | 49篇 |
1982年 | 50篇 |
1981年 | 47篇 |
1980年 | 54篇 |
1979年 | 49篇 |
1914年 | 45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 31 毫秒
1.
Tian Jie Yang Weifeng Chen Min Zheng Minfang Chen Ding Qiu Yusheng 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(2):1039-1049
Journal of Radioanalytical and Nuclear Chemistry - This study presents a time-efficient method of analysing 210Pb, 210Bi, and 210Po in natural waters. The optimum pH (1.00), temperature... 相似文献
2.
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
3.
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
4.
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
5.
Jing Zhihong Ling Baoping Yu Yang Qi Wei Zhang Shufang 《Journal of Sol-Gel Science and Technology》2015,73(1):112-117
Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants... 相似文献
6.
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
7.
8.
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
9.
10.
JPC – Journal of Planar Chromatography – Modern TLC - A new high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous estimation of... 相似文献