全文获取类型
收费全文 | 6861篇 |
免费 | 1597篇 |
国内免费 | 495篇 |
专业分类
化学 | 4319篇 |
晶体学 | 54篇 |
力学 | 218篇 |
综合类 | 39篇 |
数学 | 65篇 |
物理学 | 4258篇 |
出版年
2024年 | 19篇 |
2023年 | 83篇 |
2022年 | 181篇 |
2021年 | 229篇 |
2020年 | 246篇 |
2019年 | 233篇 |
2018年 | 204篇 |
2017年 | 298篇 |
2016年 | 250篇 |
2015年 | 273篇 |
2014年 | 316篇 |
2013年 | 531篇 |
2012年 | 513篇 |
2011年 | 485篇 |
2010年 | 356篇 |
2009年 | 432篇 |
2008年 | 368篇 |
2007年 | 515篇 |
2006年 | 413篇 |
2005年 | 342篇 |
2004年 | 310篇 |
2003年 | 324篇 |
2002年 | 248篇 |
2001年 | 225篇 |
2000年 | 185篇 |
1999年 | 138篇 |
1998年 | 150篇 |
1997年 | 116篇 |
1996年 | 131篇 |
1995年 | 96篇 |
1994年 | 101篇 |
1993年 | 83篇 |
1992年 | 117篇 |
1991年 | 66篇 |
1990年 | 62篇 |
1989年 | 61篇 |
1988年 | 36篇 |
1987年 | 43篇 |
1986年 | 33篇 |
1985年 | 29篇 |
1984年 | 25篇 |
1983年 | 10篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 3篇 |
排序方式: 共有8953条查询结果,搜索用时 109 毫秒
11.
12.
HUA Jianjun LIU Yanhong & ZHANG Zhihe . Institute of Physics Chinese Academy of Sciences Beijing China . College of Biomedical Engineering Capital University of Medical Sciences Beijing China Correspondence should be addressed to Hua Jianjun 《中国科学G辑(英文版)》2004,(1)
Adustyplasmacanbedefinedasacomplicatedplasmacontainingsmallsolidmattercalleddustgrainsordustparticles,whichareusuallychargednegatively,duetoelectronshighermobilitythanion,bycollectingelectronsandionsfromthebackgroundplasma.Theuniverseisfilledwithdustyplasmassuchasplanetaryrings,comettails,andnebulae.Also,inindustrialplasmaprocessing,particulatessuspendedinplasmaarethemajorcontaminationinsemiconductormanufacture.Studiesondustyplasmahavebeenextendedtofar-flungtopicssuchaswaves,instabilities,stro… 相似文献
13.
LIN Chang ZHANG Xiu-Lian 《理论物理通讯》2005,44(2):247-251
The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation. 相似文献
14.
G Padmaja A V Ravi Kumar V Vidyalal P Radhakrishnan V P N Nampoori C P G Vallabhan 《Pramana》1989,32(5):L693-L698
Laser induced plasma emission spectra from highT
c superconducting samples of YBa2Cu3O7 and GdBa2Cu3O7 obtained with 1.06μm radiation from a Q switched Nd:YAG laser beam has been analysed. The results clearly show the presence of diatomic oxides
in addition to ionized species of the constituent metals in the plasma thus produced. 相似文献
15.
In different regimes of exposure of metals to pulsed laser radiation, we show the role played by the liquid-drop phase formed from the target material in a laser-induced erosion plume due to bulk vaporization, in the dynamics of this plume. For some metals, the ranges of power densities of the acting laser radiation, at which the condensed-phase particles influence the passage of laser radiation to the target surface, have been determined experimentally. The mechanism of realization of a low-threshold breakdown has been revealed. 相似文献
16.
Yu. Satov B. Sharkov H. Haseroth Yu. Smakovski K. Makarov S. Kondrashev V. Roerich A. Stepanov H. Kugler R. Scrivens O. Camut A. Shumshurov A. Balabaev A. Charushin 《Journal of Russian Laser Research》2004,25(3):205-216
Experimental and numerical calculation results devoted to development of an optical system for an ion source based on a repetition rate CO2 laser are described. The laser chain consists of a master oscillator, gas absorber cells, and a four-pass amplifier. The optical system provides smooth laser pulses with variable duration and high spatial quality that ensures efficiency for plasma heating and ion generation. The parameters of the plasma ion component measured in the CERN laboratory are applied for a lead target illumination. 相似文献
17.
Jem‐Kun Chen I‐Kuan Lin Fu‐Hsiang Ko Chih‐Feng Huang Kuo‐Shen Chen Chia‐Hao Chan Feng‐Chih Chang 《Journal of Polymer Science.Polymer Physics》2004,42(22):4063-4074
Polybenzoxazine (PBZZ) thin films can be fabricated by the plasma‐polymerization technique with, as the energy source, plasmas of argon, oxygen, or hydrogen atoms and ions. When benzoxazine (BZZ) films are polymerized through the use of high‐energy argon atoms, electronegative oxygen atoms, or excited hydrogen atoms, the PBZZ films that form possess different properties and morphologies in their surfaces. High‐energy argon atoms provide a thermodynamic factor to initiate the ring‐opening polymerization of BZZ and result in the polymer surface having a grid‐like structure. The ring‐opening polymerization of the BZZ film that is initiated by cationic species such as oxygen atoms in plasma, is propagated around nodule structures to form the PBZZ. The excited hydrogen atom plasma initiates both polymerization and decomposition reactions simultaneously in the BZZ film and results in the formation of a porous structure on the PBZZ surface. We evaluated the surface energies of the PBZZ films polymerized by the action of these three plasmas by measuring the contact angles of diiodomethane and water droplets. The surface roughness of the films range from 0.5 to 26 nm, depending on the type of carrier gas and the plasma‐polymerization time. By estimating changes in thickness, we found that the PBZZ film synthesized by the oxygen plasma‐polymerization process undergoes the slowest rate of etching in CF4 plasma. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4063–4074, 2004 相似文献
18.
19.
基于可压缩的全Naiver-Stokes方程,利用PHOENICS程序对由会聚 辐射阳极形状等离子体炬产生的超声速等离子体射流进行了数值模拟.考虑了等离子体的黏性、可压缩性以及变物性对等离子体射流特性影响.研究了超声速等离子体射流的流场结构特性以及不同环境压力对等离子体射流产生激波结构的影响.结果表明,超声速等离子体射流在喷口附近形成的周期性激波结构是其和环境气体相互作用的结果.
关键词:
等离子体炬
超声速等离子体射流
PHOENICS 相似文献
20.