全文获取类型
收费全文 | 1188篇 |
免费 | 15篇 |
专业分类
化学 | 771篇 |
晶体学 | 20篇 |
力学 | 12篇 |
数学 | 64篇 |
物理学 | 336篇 |
出版年
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 27篇 |
2015年 | 23篇 |
2014年 | 20篇 |
2013年 | 44篇 |
2012年 | 52篇 |
2011年 | 64篇 |
2010年 | 47篇 |
2009年 | 43篇 |
2008年 | 63篇 |
2007年 | 62篇 |
2006年 | 58篇 |
2005年 | 48篇 |
2004年 | 45篇 |
2003年 | 55篇 |
2002年 | 62篇 |
2001年 | 32篇 |
2000年 | 38篇 |
1999年 | 14篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 18篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 19篇 |
1984年 | 14篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1968年 | 6篇 |
1967年 | 6篇 |
排序方式: 共有1203条查询结果,搜索用时 203 毫秒
131.
The neodymium isotope effects were investigated in Nd–malate ligand exchange system using the highly porous cation exchange resin SQS-6. The temperature of the chromatographic columns was kept constant at 50 °C by temperature controlled water passed through the columns jackets. The separation coefficient of neodymium isotopes, ?’s, was calculated from the isotopic ratios precisely measured by means of an ICP mass spectrometer equipped with nine collectors as ion detectors. The separation coefficient, ? × 105, were calculated and found to be 1.4, 4.8, 5.4, 10.6, 16.8 and 20.2 for 143Nd, 144Nd, 145Nd, 146Nd, 148Nd and 150Nd, respectively. 相似文献
132.
133.
134.
Takeharu Innami Ryushi Fujimura Masahiro Nomura Tsutomu Shimura Kazuo Kuroda 《Optical Review》2005,12(6):448-450
The photorefractive effect was observed in He-ion-implanted semi-insulating GaN film in the UV spectral region. The photorefractive
grating is induced by the electroabsorption effect near the band-edge. Two beam coupling experiments were performed at a wavelength
of 363.8 nm. The experimental results indicate that absorption grating mainly contributes to the beam coupling. 相似文献
135.
136.
The interaction between metal ions and bovine serum albumin (BSA) was studied by using a piezoelectric quartz crystal (PQC) arranged in the electrode-separated configuration. A silanized surface of the PQC was coated with a BSA membrane via a coupling reaction with glutaraldehyde. The frequency shifts obtained from PQC coated with a BSA membrane suggested that various kinds of metal ions could be adsorbed onto the BSA membrane from aqueous solutions containing a low concentration of metal ions (2 or 10 micromol dm(-3)), only when the BSA was denatured with an alkaline solution. Anionic species of Pt(IV) and Au(III) were adsorbed onto the denatured BSA membrane from an acetic acid solution at pH 2.2, and cationic species of Cd(II), Zn(II), Co(II), Ni(II), Cu(II), and Ag(I), and cations, such as Ca2+, Ba2+, and Mg2+, were adsorbed from ammonia buffer at pH 9.5, whereas Al(III), Cr(III), Fe(III), Hg(II), and Pb(II) were hardly adsorbed. The adsorption mechanisms of these metal ions are discussed, based on the electrostatic interaction between the metal ions and the denatured BSA membrane, and complex formation between the metal ions and amino acid residues of the denatured BSA. Further, the PQC coated with a denatured BSA membrane was applied to the determination of Pt and Cd, using large frequency shifts for Pt(IV) and Cd(II). 相似文献
137.
E. Kuzmann K. Nomura M. El-Sharif C.U. Chisholm G. Principi C. Tosello R. Gupta K. Havancsak A. Vértes 《Hyperfine Interactions》1998,112(1-4):175-178
Electrodeposited Fe-Ni-Cr alloys irradiated with 209 MeV energy 84Kr ions were investigated by conversion electron Mössbauer spectroscopy, X-ray diffraction and electron microprobe analysis. Significant dose dependent changes were found between Mössbauer spectra of the irradiated and non-irradiated deposits. These changes reflect the dose dependent transformation of the metastable ferromagnetic phase to the paramagnetic one. 相似文献
138.
D. Jancik M. Mashlan R. Zboril J. Adetunji K. Nomura 《Czechoslovak Journal of Physics》2005,55(7):803-811
A new miniaturised Mössbauer spectrometer has been developed for laboratory and industrial application. Equipped with a YAIO3:Ce crystal fast scintillation detector unit and mini transducer for the energy modulation of gamma rays, the unique mechanical design enhances protection from radiation and prevents disturbance by mechanical vibrations. It can be used with various types of cryostat and furnace.Supported by the LabVIEW graphical programming environment and by the new algorithm for the quantification of iron-components, the spectrometer can be used as a single-purpose instrument for the rapid determination of the Fe2+/Fe3+ ratio in ilmenite and Morin transition temperature of hematite. It can also be used to monitor the manufacturing processes for titanium white and copperas red. 相似文献
139.
T. Nomura 《Hyperfine Interactions》1996,103(1):33-41
We first report the recent experiment on the232Th(40Ar,α3n)265[106] reaction carried out at RIKEN to test the usefulness of the (HI,αχn)-type reaction for the production of very heavy
elements. Reaction residues recoiling out of a thin ThO2 target bombarded with 5.2 MeV/u40Ar beam were separated from the beam by using a gas-filled recoil separator and implanted onto a two-dimensionally position-sensitive
solid-state detector placed at the focal plane of the separator. The preliminary results of the analysis show that the cross
section of the above reaction is around 1 nb, being about four times larger than that of the248Cm(22Ne,5n)265[106] reaction reported in the literature. Secondly, we discuss briefly the merits and demerits of the use of a neutron-rich
beam for the production of superheavy elements, in which we stress the possibility that the demerit of weak secondary-beam
intensity is nearly cancelled out by the increase of the survival probability with the increase of the neutron number of the
compound nucleus and also by the possible enhancement of near-barrier fusion. 相似文献