全文获取类型
收费全文 | 804篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
化学 | 649篇 |
晶体学 | 7篇 |
力学 | 12篇 |
数学 | 22篇 |
物理学 | 126篇 |
出版年
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 28篇 |
2012年 | 23篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 22篇 |
2008年 | 44篇 |
2007年 | 40篇 |
2006年 | 53篇 |
2005年 | 26篇 |
2004年 | 16篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 16篇 |
2000年 | 37篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 27篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 16篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 28篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 10篇 |
1974年 | 10篇 |
1973年 | 11篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1969年 | 4篇 |
1966年 | 8篇 |
排序方式: 共有816条查询结果,搜索用时 15 毫秒
161.
162.
Kinetic study of the reactions of diphenyldiazomethane with various electron acceptors were made in six aromatic solvents. Log k were correlated with the solvent basicity parameter, Dπ, and the regression slopes were found to be a function of electron affinities. 相似文献
163.
A bicyclic dipeptide derivative with fixed conformation simulating that of the two central amino acid residues in type II′ β-turn has been synthesized starting from L-glutamic acid and L-cysteine in short steps. 相似文献
164.
165.
We measured thermal diffusivity and heat capacity of polymers by laser flash method, and the effects of measurement condition and sample size on the accuracy of the measurement are discussed. Thermal diffusivities of PTFE films with thickness 200–500 μm were the same as those data that have been reported. But, the data for film thickness less than 200 μm have to be corrected by an equation to cancel thermal resistance between sample film and graphite layers for receiving light and detecting temperature. Thermal diffusivity was almost unaffected by the size of area vertical to the direction of laser pulse, because heat flow for the direction could be negligible. Specific heat capacity of polymer film was exactly measured at room temperature, provided that low absorbed energy (< 0.3 J) and enough sample mass (> 25 mg) were satisfied as measuring conditions. Thermal diffusivity curve of PS or PC versus temperature had a terrace around Tg, whereas that of PE decreased monotonously with increasing in temperature until Tm. Further, we estimated relative specific heat capacity (RCp) by calculating ratios of heat capacities at various temperatures to the one at 299 K. RCp for PS obtained by laser flash method was larger than that obtained by DSC method, whereas the RCps for PE obtained by the both methods agreed with one another until Tm (305 K). RCp for PS decreased linearly, with increase in temperature after it increased linearly until Tg (389 K), showing similarity to temperature dependency of thermal conductivity. RCp for PE also decreased until Tm, similar to thermal conductivity. ©1995 John Wiley & Sons, Inc. 相似文献
166.
Masaya Nagai Hiroyuki Yada Takashi Arikawa Koichiro Tanaka 《International Journal of Infrared and Millimeter Waves》2006,27(4):505-515
We demonstrate time-domain attenuated total reflection spectroscopy in terahertz frequency region. Geometry of the reflection
measurement is well optimized to obtain accurate optical constants of water or aqueous biomolecular system. We determine the
dielectric constants of distilled water and sucrose solutions with this technique. This technique will open new aspects in
the research field of biological systems in water. 相似文献
167.
The zero-order desorption kinetics is described for adsorbate systems in which three phases are in equilibrium and first-order desorption kinetics is assumed for the desorption from the topmost phase. The calculated results represent typical features of the observed zero-order desorption spectra. The possibility of specifying the phase boundaries from the thermal or isothermal desorption spectra is proposed. The relationship between the thermal or isothermal desorption processes and trajectories in the phase diagram is also discussed. 相似文献
168.
Analysis of antimony around the abandoned Tsugu mine in Aichi Prefecture by neutron activation analysis 总被引:1,自引:0,他引:1
Y. Katayama A. Misawa N. Yamada S. Yachi H. Muto T. Aoki Y. Kawabata M. Nagai 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(2):283-286
At Tsugu mine in Aichi Prefecture, antimony was mined and smelted until 1956. The amounts of antimony present in the soil
of the abandoned mine were measured to enable us to detect any traces of the operation of the mine and to measure the level
of environmental contamination with antimony. The quantity of antimony in rings of hinoki and sugi was also measured to obtain
information about chronological changes in environmental conditions. The quantity of antimony in the samples was determined
by INAA. The antimony concentrations in eight soil samples at different points in the Tsugu mine area were 8–17,000 ppm. 相似文献
169.
Hiroyuki Nagai 《Hyperfine Interactions》1989,51(1-4):1003-1007
The NMR of89Y in Y(Fe1−xMnx)2 has been observed. Two kinds of Mn moments were estimated by analyzing the89Y hyperfine field: (1) the low spin state with about 0.6 μB in antiparallel to Fe moment and (2) the high spin state with about 2.8 μB in parallel to Fe moment.
The magnetizations estimated from NMR results are in good agreement with those of magnetization measurements. 相似文献
170.