全文获取类型
收费全文 | 22410篇 |
免费 | 3979篇 |
国内免费 | 3599篇 |
专业分类
化学 | 17544篇 |
晶体学 | 311篇 |
力学 | 1072篇 |
综合类 | 244篇 |
数学 | 2421篇 |
物理学 | 8396篇 |
出版年
2024年 | 50篇 |
2023年 | 424篇 |
2022年 | 610篇 |
2021年 | 818篇 |
2020年 | 985篇 |
2019年 | 917篇 |
2018年 | 800篇 |
2017年 | 859篇 |
2016年 | 1144篇 |
2015年 | 1233篇 |
2014年 | 1467篇 |
2013年 | 1840篇 |
2012年 | 2266篇 |
2011年 | 2358篇 |
2010年 | 1697篇 |
2009年 | 1548篇 |
2008年 | 1681篇 |
2007年 | 1528篇 |
2006年 | 1406篇 |
2005年 | 1027篇 |
2004年 | 783篇 |
2003年 | 576篇 |
2002年 | 646篇 |
2001年 | 538篇 |
2000年 | 418篇 |
1999年 | 418篇 |
1998年 | 290篇 |
1997年 | 280篇 |
1996年 | 223篇 |
1995年 | 210篇 |
1994年 | 171篇 |
1993年 | 179篇 |
1992年 | 119篇 |
1991年 | 99篇 |
1990年 | 80篇 |
1989年 | 70篇 |
1988年 | 50篇 |
1987年 | 55篇 |
1986年 | 33篇 |
1985年 | 37篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1959年 | 2篇 |
1957年 | 4篇 |
1916年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Tian Xiu-Zhi Yang Rui Ma Jia-Jia Ni Yong-Hao Deng Hai-Bo Dai Lei Tan Jiao-Jun Zhang Mei-Yun Jiang Xue 《高分子科学》2022,40(7):789-798
Chinese Journal of Polymer Science - Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments. Herein, polyurethane was... 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.
International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable... 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.
7.
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
8.
Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have been deemed as clean and sustainable strategies to solve the energy crisis and environmental problems. Various catalysts have been developed to promote the process of HER and OER. Among them, two-dimensional covalent organic frameworks (2D COFs) have received great attention due to their diverse and designable structure. In this minireview, we mainly summarize the diverse linkages of 2D COFs and strategies for enhancing the catalytic performance of 2D COFs for HER and OER, such as introducing active building blocks, metal ions and tailored linkages. Furthermore, a brief outlook for the development directions of COFs in the field of HER and OER is provided, expecting to stimulate new opportunities in future research. 相似文献
9.
10.
We investigate terahertz radiation(T-rays) from a pentacene organic diode at room temperature. The quantum chemistry calculation for frequency-related Huang–Rhys factor of pentacene is also carried out. The results demonstrate that the T-rays can come from a bending vibration of pentacene skeleton after the energy of pentacene exciton transferring to the vibrational excited state via electron–phonon coupling. Frequency and natural bond orbital analytics of pentacene and its derivatives are performed in order to explain the result and develop new materials to get higher emission. This work provides a new way to produce T-rays with a simple device at room temperature. 相似文献