首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   19914篇
  免费   1330篇
  国内免费   1499篇
化学   637篇
晶体学   53篇
力学   299篇
综合类   69篇
数学   203篇
物理学   12006篇
综合类   9476篇
  2024年   87篇
  2023年   280篇
  2022年   323篇
  2021年   351篇
  2020年   287篇
  2019年   147篇
  2018年   123篇
  2017年   224篇
  2016年   260篇
  2015年   404篇
  2014年   1042篇
  2013年   893篇
  2012年   1210篇
  2011年   1248篇
  2010年   1192篇
  2009年   1226篇
  2008年   1392篇
  2007年   1269篇
  2006年   1004篇
  2005年   1057篇
  2004年   1447篇
  2003年   1264篇
  2002年   1097篇
  2001年   936篇
  2000年   900篇
  1999年   529篇
  1998年   431篇
  1997年   386篇
  1996年   333篇
  1995年   235篇
  1994年   216篇
  1993年   159篇
  1992年   204篇
  1991年   173篇
  1990年   155篇
  1989年   169篇
  1988年   28篇
  1987年   22篇
  1986年   16篇
  1985年   8篇
  1984年   1篇
  1983年   6篇
  1982年   4篇
  1981年   1篇
  1980年   2篇
  1965年   1篇
  1962年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
《大学物理》2006,25(10):F0004-F0004
南京航空航天大学应用物理系有36人,其中教授8人,拥有博士学位教师24人。现有“凝聚态物理”二级学科和“光学工程”一级学科等学科的博士学位授予权,“物理学”和“光学”工程等一级学科、“物理电子学”和“光学工程”工程硕士专业领域等硕士学位授予权,以及“应用物理学”本科专业。  相似文献   
912.
The evolution of shower parton distributions in a jet is investigated in the framework of a quark recombination model. The distributions are parameterized and the Q^2 dependence of the parameters is given by polynomials of In Q^2 for a wide range of Q^2  相似文献   
913.
Following a previous systematic theoretical study of the ground-state properties of over 7000 nuclei from the proton drip line to the neutron drip line in the relativistic mean field model [Prog. Theor. Phys. 113 (2005) 785], which is in fair agreement with existing experimental data, we observe a few spurious shell closures, i.e. proton shell closures at Z = 58 and Z = 92. These spurious shell closures are found to persist in all the effective forces of the relativistic mean field model, e.g. TMA, NL3, PKDD and DD-ME2.  相似文献   
914.
A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSⅡ) is proposed for inner surface modification of tubes. In MGA-PSⅡ, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TIN) films are prepared on the inner surface of a stainless steel tube in diameter 90mm and length 600mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.  相似文献   
915.
The stochastic resonance in an over-damped bias linear system subject to multiplicative and additive dichotomous noise (DN) is investigated. By using the linear-response theory and the properties of the DN, the exact expressions are found for the signal-to-noise ratio (SNR). It is shown that the SNR is a non-monotonic function of the correlation time of the additive DN, and it varies non-monotonically with the bias of the external field, the intensity and asymmetry of the multiplicative DN, as well as the external field frequency. Moreover, the SNR depends on the bias of the system, as well as the strength and asymmetry of the additive DN.  相似文献   
916.
The phonon dispersion curves (PDC) of Ca70Mg30 metallic glass has been studied at room temperature in terms of phonon eigen frequencies of longitudinal and transverse modes employing three different approaches proposed by Hubbard and Beeby (J. Phys. C: Solid State Phys. 13 (1969) 556), Takeno and Goda (Prog. Theor. Phys. 45 (1971) 331; 47 (1972) 790) and Bhatia and Singh (Phys. Rev. B 31 (1985) 4751). The well recognized model potential of Gajjar et al. is employed successfully to explain electron-ion interaction in the metallic glass. The effective pair potential is used to generate the pair correlation function g(r). The local field correction function (Int. J. Mod. Phys. B 17 (2003) 6001) is used for the first time to introduce the exchange and correlation effects on the aforesaid properties. The present findings of PDCs are found to be in agreement with the available theoretical as well as experimental data. The thermodynamic and elastic properties, i.e. longitudinal and transverse sound velocities, isothermal bulk modulus, modulus of rigidity, Poisson's ratio, Young's modulus and Debye temperature, are also investigated successfully.  相似文献   
917.
Non-recycling impurities are injected into ohmic HL-2A plasma for the first time. The impurities of titanium and aluminium are injected in the discharges with varying plasma density and current. The convection and diffusion process of the injected impurity ions during the inward phase are qualitatively investigated. The results show that the transport of impurities is much slower in the central region of the plasma than outside of it and that it is greatly enhanced during sawtooth crashes.  相似文献   
918.
The duplication and divergence process is ubiquitous in nature and man-made networks. Motivated by the duplication-divergence mechanism which depicts the growth of protein networks, we propose a weighted network model in which topological evolution is coupled with weight dynamics. Large scale numerical results indicate that our model can naturally generate networks with power-law-like distributions of degree, strength and weight. The degree-strength correlation is illustrated as well. These properties are in agreement well with empirical data observed in real-world systems. Furthermore, by altering the retention probability δ, weighted, structured exponential networks are realized.  相似文献   
919.
《发光学报》2006,27(6):916-916
由中国物理学会发光分会、中国稀土学会发光专业委员会主办,中国科学院激发态物理重点实验室承办,海南大学理工学院协办的第1届掺杂纳米材料发光性质学术会议于2006年11月5~7日在海南省海口市举行。这是国内外举办的首次掺杂纳米发光材料方面的专题学术研讨会。来自全国20个省市49个单位、香港地区(3人)以及美国(2人)、荷兰(1人)的专家学者总计100余人出席了此次会议。会议共收录论文摘要101篇,其中大会邀请报告8篇、分会邀请报告12篇、口头报告36篇、张贴报告45篇。内容涉及到:新型纳米发光材料与新的纳米合成、组装技术;纳米材料发光中的激发态过程;上转换纳米发光材料;纳米材料中的限域效应、表面效应及其诱导的新现象;表面修饰与核壳结构的纳米材料;一维纳米材料线、管及纳米薄膜的结构与发光性质;掺杂纳米材料发光中的新概念、新理论.  相似文献   
920.
《物理实验》2006,26(11):29-29
安康学院的方小兵老师来信指出:在《物理实验》2006年第2期上,关于“超声波波型转换与表面波的检测”一文中,出现波形与波型混用.波形和波型,虽然都是用来描述波的性质,但两者没有任何因果关系,波形由波源的振动决定,由示波器来显示,波型则是通过测量声速来判定,它的类型由波源和介质共同决定且在介面上能发生波型转换.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号