全文获取类型
收费全文 | 536篇 |
免费 | 82篇 |
国内免费 | 40篇 |
专业分类
化学 | 264篇 |
晶体学 | 9篇 |
力学 | 27篇 |
综合类 | 6篇 |
数学 | 17篇 |
物理学 | 335篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 21篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 23篇 |
2015年 | 21篇 |
2014年 | 35篇 |
2013年 | 33篇 |
2012年 | 30篇 |
2011年 | 29篇 |
2010年 | 25篇 |
2009年 | 25篇 |
2008年 | 36篇 |
2007年 | 34篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 32篇 |
2003年 | 26篇 |
2002年 | 20篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 14篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 21篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有658条查询结果,搜索用时 15 毫秒
1.
An experimental method is developed to examine the near tip deformation at the mesoscopic scale level. The differential interference contrast (DIC) method is used by application of the Nomarski prism in polarized microscope for measuring the out of surface deformation. The method is very sensitive to small height changes detected by different interference color. Discussed are results for the crack tip deformation field. 相似文献
2.
3.
We analyze the polarization changes introduced by a rotated Dove prism on the linearly polarized light, using the Jones calculus and the exact ray trace analysis. The state of polarization changes from the linear to a mildly elliptical one when a plane wave front passes through a rotated Dove prism: its semi-major axis is nearly parallel to the input plane of polarization, for any angle of prism rotation. The interferogram contrast remains high for all shearing angles in spite of polarization changes when the Dove prism is incorporated into a rotational shearing interferometer. These results are confirmed experimentally. 相似文献
4.
5.
In this paper, based on known crystal structures of square pyramid (SP) and trigonal bipyramid (TBP) penta coordinated phosphorus compounds containing amino acid side chains, such as amino, carboxyl, hydroxyl or thiol, a software for survey the P(5)-structure of phosphorylated proteins was derived. By this software, it was found that 382 of 398 phosphorus related kinases (96%) from current PDB could go through the penta-coordinated phosphorus transition state or intermediate. 相似文献
7.
0IntroductionThestudyofcopper?complexesisinvestigatedinmanylaboratories.Amongthereasonsforcarryingouttheinvestigationofsuchspeciesaretheirstructuralfeatures犤1犦,theusefulnessofcopper?compoundsinorganicsyntheses犤2犦andthewell-documentedimpor-tanceofcopper?centersattheactivesitesofanumberofprotein犤3犦.Concerningcopper?carboxy-latesafurtherinterestexists,stemmingfromtheiruseinhomogeheouscatalysedhydrogenation犤4犦.Thecopper?bis(triphenylphosphine)cationisasoft,butflexi-bleacceptorionthatcanacc… 相似文献
8.
吡啶—2,6—二羧酸体系导数荧光法同时测定铀,钐,铕,铽,镝 总被引:4,自引:0,他引:4
本研究了吡啶-2,6-二羧酸(DPA)体系导数荧光法同时测定铀,钐,铕,铽,镝的最佳条件。在pH5.5,4.8×10^-^5mol/LDPA,激发波长272nm的条件下,可分别在518,639,621,539和66nm处测定铀,钐,铕,铽和镝,检测限分别达到7,0.4,0.004,0.026和0.25ng/mL。应用本法测定了混合成试液中上术五种离子含量,回收率为92.3-108.1%。 相似文献
9.
Khoroshen'kov G. V. Fag A. A. Bochkarev M. N. Dechert S. Schumann H. 《Russian Chemical Bulletin》2003,52(8):1715-1719
The reactions of LnI2 (Ln = Nd (1) or Dy (2)) with cyclopentadiene (CpH) in THF at 0 °C afforded the CpLnI2(THF)3 complexes in 65—67% yields. The reaction of thulium diiodide (3) with an excess of CpH at 60 °C produced CpTmI2(THF)3, Cp2TmI(THF)2, and TmI3(THF)3 in 21, 58, and 63% yields, respectively. The reactions of 1 and 2 with pentamethylcyclopentadiene (Cp*H) in THF were accompanied by disproportionation giving rise to the Cp*2LnI(THF)2 and LnI3(THF)
x
complexes. Neodymium triiodide was isolated in the ionic form [NdI2(THF)5]+[NdI4(THF)2]–. Its structure and the structure of CpTmI2(THF)3 were established by X-ray diffraction analysis. 相似文献
10.
本文报道了不同组成的YPxV1-xO4(0≤x≤1):Dy^3+的合成和结构。YPxV1-xO4(0≤x≤1)为四方晶系,晶胞参数随x的增大呈线性减小。基质的Stokes位移随x的增大逐渐变大,而激发光谱峰值则向短波方向移动。在YPxV1-xO4:0.006Dy^3+体系中,x>0.4时出现的基质发射是由PO^3-4引起的。基质及Dy^3+的发光效率和Dy^3+的发光强度的黄蓝比均与x有关。同时探 相似文献