全文获取类型
收费全文 | 739篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
化学 | 557篇 |
晶体学 | 15篇 |
力学 | 7篇 |
数学 | 18篇 |
物理学 | 158篇 |
出版年
2021年 | 3篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 16篇 |
2012年 | 32篇 |
2011年 | 38篇 |
2010年 | 26篇 |
2009年 | 23篇 |
2008年 | 50篇 |
2007年 | 65篇 |
2006年 | 32篇 |
2005年 | 40篇 |
2004年 | 44篇 |
2003年 | 38篇 |
2002年 | 30篇 |
2001年 | 35篇 |
2000年 | 29篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1966年 | 3篇 |
1965年 | 4篇 |
排序方式: 共有755条查询结果,搜索用时 15 毫秒
101.
Kitagawa O Takahashi M Yoshikawa M Taguchi T 《Journal of the American Chemical Society》2005,127(11):3676-3677
In the presence of (R)-DTBM-SEGPHOS-Pd(OAc)2 catalyst, N-arylation of ortho-tert-butyl-NH-anilides with 4-nitroiodobenzene proceeds with high enantioselectivity (89-95% ee) to give optically active atropisomeric anilides possessing N-C chiral axis. Furthermore, the intramolecular version of the present catalytic asymmetric N-arylation gave atropisomeric lactams with high optical purity (94-96% ee). 相似文献
102.
A new method is proposed for reconstructing wavefront from discretely sampled interferogram data obtained by a digital lateral shearing interferometer. Assumptions applied in the conventional methods are not used and reconstruction error caused by the difference between the amount of shear and the sampling interval can be removed. System error and the influence of the discrete sampling, which limit accuracy of the tested results of the lateral shearing interferometer, are analyzed. 相似文献
103.
104.
H. N. Yoshikawa F. Zoueshtiagh H. Caps P. Kurowski P. Petitjeans 《The European physical journal. E, Soft matter》2010,31(2):191-199
The stability of centimeter scale air bubbles is studied in quiescent suspending liquid under an imposed oscillatory acceleration
field. Experiments were performed in reduced- and normal-gravity environments. A strong acceleration resulted in an instability
leading to the breakups of the bubbles in both gravity environments. The breakup onset was investigated and found to be characterized
by a critical acceleration a
cr . The influence of the liquid viscosity and the gravitational environment was studied. Empirical correlations for the onset
are presented and discussed with the intention to reveal splitting mechanism. The inertial mechanism often deemed to cause
the breakup of drops subjected to a rapid gas stream is shown to give explanations consistent with the experiments. A breakup
criterion for both gravitational environments is proposed through discussions from an energetic point of view. 相似文献
105.
Akihiro Fukabori Takayuki Yanagida Federico Moretti Yuui Yokota Rayko Shimura Shuji Maeo Jan Pejchal Kei Kamada Akira Yoshikawa 《Radiation measurements》2010,45(3-6):453-456
Micro-pulling down (μ-PD) method allows to prepare single crystals quickly and relatively inexpensively. Since it is a melt growth and taking into account segregation phenomena, the μ-PD method allows also to obtain single crystals characterized by dopant concentration gradients. Especially, taking the advantage of the grown crystal high aspect ratio, it allows to prepare crystalline samples with variable and wide range concentrations of dopants. These samples can help in understanding the correlation between dopant concentration and luminescence properties. 相似文献
106.
Novel indeno[1,2-b]benzo[4,5-e]pyran-11-one-type fluorophores exhibiting intense solid-state fluorescence were conveniently synthesized and the relation between their solid-state photophysical properties and the X-ray crystal structures were investigated, which demonstrates that non-planar structures with sterical hindered substituents prevent the fluorophores from forming short pi-pi contacts causing fluorescence quenching in the solid state. 相似文献
107.
Yoshikawa M Kawamura K Ejima A Aoki T Sakurai S Hayashi K Watanabe K 《Macromolecular bioscience》2006,6(3):210-215
Novel molecular recognition materials were prepared from water soluble proteins from thermophile G. thermodenitrificans DSM465 by an alternative molecular imprinting method. Water soluble proteins from G. thermodenitrificans DSM465 were converted into the molecularly imprinted materials by adopting 9-EA as a print molecule. The molecularly imprinted protein membranes recognized As in preference to Gs. The adsorption isotherms led to the conclusion that molecular recognition sites toward As were constructed by the presence of 9-EA during the membrane preparation process. The affinity constant between As and the molecular recognition site thus constructed was determined to be 1.75 x 10(5) mol(-1) dm(3). The results obtained in the present study suggest that water soluble proteins from G. thermodenitrificans DSM465 is one of environmentally-friendly 'green' polymers to be converted into molecular recognition materials by applying an alternative molecular imprinting method. 相似文献
108.
Masatomo Sumiya Yutaro Kamo Masaki Takeguchi Hideki Yoshikawa Keisuke Kobayashi Minoru Hagino Shunro Fuke 《Applied Surface Science》2010,256(14):4442-4446
Photocathode devices operating in reflection-mode, where the photoemission is detected on the same side as the light irradiation, were developed for the detection of deep ultraviolet light by using p-AlxGa1−xN films grown on Si(1 1 1) substrates. The external quantum efficiencies were as high as 20-15% at 200 nm and 280 nm, while the value was as low as 10−2% at 310 nm. The on-off ratio was more than four orders of magnitude, which represents high solar-blind sensitivity. The escape probability of AlxGa1−xN photocathode was decreased with increase of AlN mole fraction. The effective barrier potential against the photoelectron emission near the surface was reduced due to the upward shift of conduction band of AlxGa1−xN. The photoemission from the AlxGa1−xN films terminated with Cs-O adatoms will be discussed in terms of band diagrams that were evaluated by hard X-ray photoelectron spectroscopy. 相似文献
109.
M. Nikl A. Yoshikawa K. Kamada K. Nejezchleb C.R. Stanek J.A. Mares K. Blazek 《Progress in Crystal Growth and Characterization of Materials》2013,59(2):47-72
A review of research and development of Lu3Al5O12 (LuAG)-based single crystal scintillators is presented. Crystals of this type have been prepared by the micro-pulling down method at the initial stage of material screening and by Czochralski or Bridgman methods to obtain higher quality and larger size single crystals afterward. Several different activators, namely Ce3+, Pr3+, Yb3+ and Sc3+ have been reported in the literature and such doped LuAG single crystals have been extensively studied to understand a number of issues, including: the scintillation mechanism, underlying energy transfer and trapping processes including the nature and role of material defects involved in the scintillation process and their relation to manufacturing technology. Significant improvements in the understanding of aluminum garnet scintillators lead to the discovery of multicomponent garnet single crystal scintillators in 2011, which are described. These materials gave rise to new class of ultraefficient complex oxide scintillators, the light yield of which considerably exceeds the values achieved for the best Ce-doped orthosilicate scintillators. 相似文献
110.
Masayoshi Yoshikawa 《代数通讯》2013,41(5):2046-2060
We will investigate the structure of noncommutative imprimitive association schemes of rank 6 and the representation of their adjacency algebras. From this investigation, we will construct new integral standard generalized table algebras with three parameters. These algebras are noncommutative, imprimitive, and 6-dimensional. 相似文献