全文获取类型
收费全文 | 233篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
化学 | 187篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 1篇 |
物理学 | 53篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 15篇 |
2012年 | 10篇 |
2011年 | 15篇 |
2010年 | 6篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1932年 | 2篇 |
排序方式: 共有244条查询结果,搜索用时 203 毫秒
161.
S.D. Ellis J. Huston K. Hatakeyama P. Loch M. Tnnesmann 《Progress in Particle and Nuclear Physics》2008,60(2):484-551
In this article, we review some of the complexities of jet algorithms and of the resultant comparisons of data to theory. We review the extensive experience with jet measurements at the Tevatron, the extrapolation of this acquired wisdom to the LHC and the differences between the Tevatron and LHC environments. We also describe a framework (SpartyJet) for the convenient comparison of results using different jet algorithms. 相似文献
162.
Y.F. Li R. Hatakeyama T. Kaneko 《Applied Physics A: Materials Science & Processing》2007,88(4):745-749
Electrical transport properties of double-walled carbon nanotubes (DWNTs) are modulated by encapsulating alkali-metal Cs atom
or C60 molecules via a plasma ion-irradiation method. The pristine DWNTs are found to exhibit ambipolar semiconducting behavior
due to their small bandgap. In contrast, Cs and C60 encapsulated DWNTs exhibit high performance unipolar n-type and p-type semiconducting behavior since they can operate as
an electron donor and acceptor, respectively. Moreover, by controlling the filling level, p–n junction is found to be formed
in DWNTs by Cs encapsulation. Our results indicate that DWNTs have great potential as building blocks for various electronic
nano devices.
PACS 73.63.Fg; 73.63.-b; 61.48.+c 相似文献
163.
164.
New theoretical expressions of probability density and cumulative distribution functions for the output response are exactly derived without any simplification of the problem and any approximation of analysis in the case when a general random signal with arbitrary probability distribution and correlation functions is passed through an arbitrary linear vibratory system with finite order. The result is given as an explicit solution of expansion series in a functional form of input statistics and vibratory system parameters, and not given as a mere numerical solution by use of a recurrence algorithm. An effect of random input and system characteristics is concretely reflected in the expansion coefficients. The experimental results obtained by digital simulation are in good agreement with the theory. Thus, the above theory is experimentally confirmed for some typical examples by the method of digital simulation. 相似文献
165.
Ohne Zusammenfassung 相似文献
166.
Y. Shimura und T. Hatakeyama 《Colloid and polymer science》1977,255(9):933
Ohne Zusammenfassung 相似文献
167.
M. Takahashi M. Iijima K. Kimura T. Hatakeyama H. Hatakeyama 《Journal of Thermal Analysis and Calorimetry》2006,85(3):669-674
The viscoelasticity and thermal properties of aqueous
solutions of blended xanthan gum (XA) with chitosan were investigated in order
to study the electrostatic interaction established between two polysaccharides.
Storage modulus G’, loss modulus G” and zero shear rate viscosity ηO
attain a maximum at a chitosan concentration C
max.
The above results indicate that the junction between XA and chitosan is formed
in a concentration range lower than C
max
and the viscoelasticity of systems increases with increasing concentration.
In a concentration range higher than C
max,
junction formation may not occur effectively since the excess amount of chitosan
completely screens anions of XA. The chain rigidity of XA decreases by the
screening of the repulsive interaction between anions on XA chains. The ineffective
junction formation and the decrease of XA chain rigidity may cause the decrease
of viscoelasticity of systems with increasing concentration. The value of C
max decreases with increasing
molecular mass of chitosan. From melting enthalpy of the above system measured
by DSC, the amount of non-freezing water (W
nf)
was evaluated. W
nf
shows a minimum at the concentration C
max.
This fact suggests that hydrophobic fields increased by junction structure
formation through ion-complexation between XA and chitosan molecules. 相似文献
168.
Microgram-scale testing of reaction conditions in solution using nanoliter plugs in microfluidics with detection by MALDI-MS 总被引:2,自引:0,他引:2
This paper describes a microfluidic system to screen and optimize organic reaction conditions on a submicrogram scale. The system uses discrete droplets (plugs) as microreactors separated and transported by a continuous phase of a fluorinated carrier fluid. Previously, we demonstrated the use of a microfabricated PDMS plug-based microfluidic system to perform assays and crystallization experiments in aqueous solutions with optical detection. Here, we developed an approach that does not require microfabrication of microfluidic devices, is applicable to synthetic reactions in organic solvents, and uses detection by MALDI-MS. As a demonstration, conditions for selective deacetylation of ouabain hexaacetate were tested, and the optimum conditions for mono-, bis-, or trisdeacetylation have been identified. These conditions were validated by scale-up reactions and isolating these potentially neurotoxic products. Mono- and bisdeacetylated products are unstable intermediates in the deacetylation and were isolated for the first time. This system enables no-loss handling of submicroliter volumes containing a few micrograms of a compound of interest. It could become valuable for investigating or optimizing reactions of precious substrates (e.g., products of long synthetic sequences and natural products that can be isolated only in small quantities). 相似文献
169.
Takahashi K Matsumura T Corbin GR Ishihara J Hatakeyama S 《The Journal of organic chemistry》2006,71(11):4227-4231
Neodysiherbaine A, a neuroexitotoxin occurring in a Micronesian marine sponge Dysidea herbacea, was synthesized from tri-O-acetyl-D-glucal with excellent stereocontrol. The method established enables us to obtain gram quantities of neodysiherbaine A and its related compounds. 相似文献
170.
The Rishiri Fall Experiment (RISFEX ) campaign was performed in September 2003 at Rishiri island (45.07 N, 141.12 E, and 35
m asl) in the sea of Japan to investigate photochemical production of ozone in the marine boundary layer. Total peroxy radicals
RO
x
(HO2 + RO2) and NO
x
(NO + NO2) were measured together with other chemical species and physical parameters relevant to ozone production. The ozone production
rate (P(O3)) was estimated from measured peroxy radicals and was found to be highly variable between days, with 30-min averaged midday
values varying from 0.2 to 1.7 ppbv/h (ppbv refers to part per billion by volume). The daytime mean P(O3) for the air masses from relatively clean NE sector is close to zero, but significantly higher for air masses from more polluted
W and SE sector, suggesting the impact of transport of pollutants on the remote local ozone production. The experimentally
determined P(O3) is compared with those derived from a time-dependent box model based on Regional Atmospheric Chemistry Modeling (RACM),
and both the methods give the results generally in agreement. The model calculation shows that HO2 + NO reaction contributes most to ozone production, ca. 60% at midday, followed by the reactions of CH3O2 and ISOP (peroxy radicals formed from isoprene) with NO which account for ca. 13% and 10% to ozone production, respectively,
at noon. Sensitivity analysis indicates that the ozone production during the measurement period is within NO
x
-limited regime. 相似文献