全文获取类型
收费全文 | 9041篇 |
免费 | 1912篇 |
国内免费 | 2134篇 |
专业分类
化学 | 6656篇 |
晶体学 | 264篇 |
力学 | 797篇 |
综合类 | 289篇 |
数学 | 1098篇 |
物理学 | 3983篇 |
出版年
2024年 | 35篇 |
2023年 | 147篇 |
2022年 | 349篇 |
2021年 | 371篇 |
2020年 | 412篇 |
2019年 | 353篇 |
2018年 | 349篇 |
2017年 | 413篇 |
2016年 | 406篇 |
2015年 | 502篇 |
2014年 | 612篇 |
2013年 | 723篇 |
2012年 | 793篇 |
2011年 | 806篇 |
2010年 | 645篇 |
2009年 | 717篇 |
2008年 | 701篇 |
2007年 | 596篇 |
2006年 | 566篇 |
2005年 | 532篇 |
2004年 | 440篇 |
2003年 | 333篇 |
2002年 | 347篇 |
2001年 | 384篇 |
2000年 | 307篇 |
1999年 | 220篇 |
1998年 | 164篇 |
1997年 | 107篇 |
1996年 | 117篇 |
1995年 | 86篇 |
1994年 | 97篇 |
1993年 | 91篇 |
1992年 | 66篇 |
1991年 | 51篇 |
1990年 | 39篇 |
1989年 | 33篇 |
1988年 | 38篇 |
1987年 | 19篇 |
1986年 | 24篇 |
1985年 | 20篇 |
1984年 | 14篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1962年 | 2篇 |
1960年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
931.
PENG ChiaKuei 《中国科学 数学(英文版)》2010,(1)
Let M be a closed oriented surface immersed in R4 . Associated it one has the generalized Gauss map from M into the Grassmann manifold G 4,2 . This note will be concerned with the geometry of the generalized Gauss map by using the moving frame theory and the quaternion interpretation of Plcker coordinates. As one of consequences,we get the celebrated theorem of Chern and Spanier,Hoffman and Osserman,who proved it by quite different methods. At last,we give an explicit construction of a series of immersions of S2 in R4 with any given normal Euler number. 相似文献
932.
A new method for the synthesis of substituted thiophenes was through intramolecular aldol condensation of α-oxo ketene dibenzylthioacetals.All products were confirmed with IR,1H NMR and elemental analysis. 相似文献
933.
介绍了测量不确定度的评定方法及其在基准试剂纯度、干涉滤光片波长标准物质、锌合金成分标准物质中的应用实例。 相似文献
934.
Jianming Dai Weili Zhang Lizhe Zhang Lu Chai Yong Wang Zhigang Zhang Qirong Xing Ching-yue Wang Kenji Torizuka Tadashi Nakagawa Takeyoshi Sugaya 《Optics & Laser Technology》2001,33(2)
In this paper, a self-starting, diode-pumped self-mode-locked Cr:LiSGAF laser, which produced a stable pulse train of 45 fs duration with about 20 mW-average power at the repeated rate of 90 MHz, was presented. Self-mode-locked operation can be obtained whether there is the semiconductor saturable absorber mirror (SESAM) in the Cr:LiSGAF laser cavity or not, and with the SESAM in the cavity, the self-mode-locked operation could self-start. The shortest pulses, as short as 38 fs, which were not very stable, were obtain with the SESAM in the cavity. 相似文献
935.
区域稳定动力学研究(二)——基本原则 总被引:1,自引:0,他引:1
区域稳定动力学是一个多源、多层次、多子系统、多影响因素的复合动力学系统, 本文提出了研究这一复合动力学系统的六个基本原则, 即连续性原则、立体性原则、系统性原则、非线性原则、动态性原则及工程实用原则。 相似文献
936.
937.
Huang Yun Liu Bo Cao Haijun Lin Yuanhua Tang Shuihua Wang Mingshan Li Xing 《Journal of Solid State Electrochemistry》2017,21(8):2291-2299
Journal of Solid State Electrochemistry - One novel cage kind of polyhedral ligomeric silsesquioxane (POSS), for modification application of gel polymer electrolyte (GPE) in lithium ion batteries... 相似文献
938.
To model red blood cell (RBC) deformation and multiple‐cell interactions in flow, the recently developed technique derived from the lattice Boltzmann method and the distributed Lagrange multiplier/fictitious domain method is extended to employ the mesoscopic network model for simulations of RBCs in flow. The flow is simulated by the lattice Boltzmann method with an external force, while the network model is used for modeling RBC deformation. The fluid–RBC interactions are enforced by the Lagrange multiplier. To validate parameters of the RBC network model, stretching tests on both coarse and fine meshes are performed and compared with the corresponding experimental data. Furthermore, RBC deformation in pipe and shear flows is simulated, revealing the capacity of the current method for modeling RBC deformation in various flows. Moreover, hydrodynamic interactions between two RBCs are studied in pipe flow. Numerical results illustrate that the leading cell always has a larger flow velocity and deformation, while the following cells move slower and deform less.Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
939.
ZHAO Xiao-ping JIN Ye-cheng ZENG Xing ZHANG Bo-li ZHANG Yu-feng .Tianjin State Key Laboratory of Modern Chinese Medicine Tianjin University of Traditional Chinese Medicine Tianjin P.R.China .College of Preclinical Medicine Zhejiang Chinese Medical University Hangzhou .College of Pharmaceutical Sciences Zhejiang University Hangzhou 《高等学校化学研究》2011,(4):562-565
In order to identify the potential nephrotoxic compounds in traditional Chinese medicine Lithospermum erythrorhizon,it was separated into serial fractions according to their polarities.An in vitro method was utilized to determine the nephrotoxicity of these fractions with the help of fluorescence image analysis.As a result,the primary fraction A05 and its secondary fractions C06 C09 and C12 C14 were found to have significant toxicity to LLC-PK1 cell line,as determined by the survive rate less than 20% after... 相似文献
940.
In this paper,we study the complete q-moment convergence of moving average processes under -mixing assumption.The results obtained not only extend some previous known results,but also improve them. 相似文献