全文获取类型
收费全文 | 32836篇 |
免费 | 5493篇 |
国内免费 | 4542篇 |
专业分类
化学 | 23881篇 |
晶体学 | 406篇 |
力学 | 1904篇 |
综合类 | 438篇 |
数学 | 3899篇 |
物理学 | 12343篇 |
出版年
2024年 | 16篇 |
2023年 | 579篇 |
2022年 | 637篇 |
2021年 | 855篇 |
2020年 | 1232篇 |
2019年 | 1225篇 |
2018年 | 984篇 |
2017年 | 967篇 |
2016年 | 1461篇 |
2015年 | 1427篇 |
2014年 | 1755篇 |
2013年 | 2344篇 |
2012年 | 2862篇 |
2011年 | 2992篇 |
2010年 | 2241篇 |
2009年 | 2151篇 |
2008年 | 2419篇 |
2007年 | 2257篇 |
2006年 | 2144篇 |
2005年 | 1719篇 |
2004年 | 1409篇 |
2003年 | 1199篇 |
2002年 | 1049篇 |
2001年 | 863篇 |
2000年 | 736篇 |
1999年 | 732篇 |
1998年 | 622篇 |
1997年 | 504篇 |
1996年 | 508篇 |
1995年 | 464篇 |
1994年 | 431篇 |
1993年 | 386篇 |
1992年 | 325篇 |
1991年 | 276篇 |
1990年 | 273篇 |
1989年 | 181篇 |
1988年 | 144篇 |
1987年 | 107篇 |
1986年 | 113篇 |
1985年 | 82篇 |
1984年 | 43篇 |
1983年 | 53篇 |
1982年 | 40篇 |
1981年 | 22篇 |
1980年 | 10篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1973年 | 3篇 |
1970年 | 3篇 |
1957年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Acta Mathematicae Applicatae Sinica, English Series - So far there have been few results presented on the exponential stability for time-changed stochastic differential equations. The main aim of... 相似文献
2.
Liu Zhu Sun Wen-Yang Fan Xiao-Gang Wang Dong Ye Liu 《International Journal of Theoretical Physics》2021,60(7):2412-2422
International Journal of Theoretical Physics - In this paper, we investigate Einstein-Podolsky-Rosen steering, Bell non-locality, first-order coherence and concurrence in the spin- $\frac {1}{2}$... 相似文献
3.
Potential Analysis - The purpose of this paper is to provide necessary and sufficient conditions of the boundedness for singular integrals on the local Hardy space and its dual. Particularly the... 相似文献
4.
This study is to numerically test the interfacial instability of ferrofluid flow under the presence of a vacuum magnetic field. The ferrofluid parabolized stability equations(PSEs) are derived from the ferrofluid stability equations and the Rosensweig equations, and the characteristic values of the ferrofluid PSEs are given to describe the ellipticity of ferrofluid flow. Three numerical models representing specific cases considering with/without a vacuum magnetic field or viscosity are created to mathematically examine the interfacial instability by the computation of characteristic values. Numerical investigation shows strong dependence of the basic characteristic of ferrofluid Rayleigh-Taylor instability(RTI) on viscosity of ferrofluid and independence of the vacuum magnetic field.For the shock wave striking helium bubble, the magnetic field is not able to trigger the symmetry breaking of bubble but change the speed of the bubble movement. In the process of droplet formation from a submerged orifice, the collision between the droplet and the liquid surface causes symmetry breaking. Both the viscosity and the magnetic field exacerbate symmetry breaking. The computational results agree with the published experimental results. 相似文献
5.
Song Zi-Long Zhu Yun Liu Jing-Rui Guo Shu-Ke Gu Yu-Cheng Han Xinya Dong Hong-Qiang Sun Qi Zhang Wei-Hua Zhang Ming-Zhi 《Molecular diversity》2021,25(1):205-221
Molecular Diversity - Based on the strategy of diversity-oriented synthesis and the structures of natural product pimprinine and streptochlorin, two series of novel pimprinine derivatives... 相似文献
6.
Nonlinear Dynamics - The paper studies the stability and control of radial deployment of an electric solar wind sail with the consideration of high-order modes of elastic tethers. The electric... 相似文献
7.
Chinese Journal of Polymer Science - The emerging chemical recyclable polymers, such as poly(γ-butyrolactone) (PGBL) and poly((R)-3,4-trans six-membered ring-fused GBL) (P((R)-M)), provide a... 相似文献
8.
Li Hongying Liu Xiaoxuan Huang Jiaqi Zhu Wenjuan Ding Aimin Yao Chengli Zhu Jinmiao 《Crystallography Reports》2022,67(7):1231-1238
Crystallography Reports - Sodium dodecyl sulfonate and rape pollen were selected as soft and hard templates to induce ZnO formation under hydrothermal conditions, respectively. In the preparation... 相似文献
9.
Czechoslovak Mathematical Journal - The irregularity of a graph G = (V, E) is defined as the sum of imbalances ∣du ? dv∣ over all edges uv ∈ E, where du denotes the degree... 相似文献
10.
SHANG Anqi ZHAO Lele LI Zhenhua CHENG Zhuang JIN Haixu FENG Zijun CHEN Zhijun ZHANG Haiquan LU Ping 《高等学校化学研究》2022,38(6):1461-1466
Near-infrared(NIR) fluorescent materials with high photoluminescent quantum yields(PLQYs) have wide application prospects. Therefore, we design and synthesize a D-A type NIR organic molecule, TPATHCNE, in which triphenylamine and thiophene are utilized as the donors and fumaronitrile is applied as the acceptor. We systematically investigate its molecular structure and photophysical property. TPATHCNE shows high Tgof 110℃ and Td of 385℃ and displays an aggregation-induced emission(AIE) property. A narrow optical bandgap of 1.65 eV is obtained. The non-doped film of TPATHCNE exhibits a high PLQY of 40.3% with an emission peak at 732 nm, which is among the best values of NIR emitters. When TPATHCNE is applied in organic light-emitting diode(OLED), the electroluminescent peak is located at 716 nm with a maximum external quantum efficiency of 0.83%. With the potential in cell imaging, the polystyrene maleic anhydride(PMSA) modified TPATHCNE nanoparticles(NPs) emit strong fluorescence when labeling HeLa cancer cells, suggesting that TPATHCNE can be used as a fluorescent carrier for specific staining or drug delivery for cellular imaging. TPATHCNE NPs fabricated by bovine serum protein(BSA) are cultivated with mononuclear yeast cells, and the intense intracellular red fluorescence indicates that it can be adopted as a specific stain for imaging. 相似文献