全文获取类型
收费全文 | 671篇 |
免费 | 21篇 |
国内免费 | 1篇 |
专业分类
化学 | 515篇 |
晶体学 | 6篇 |
力学 | 5篇 |
数学 | 29篇 |
物理学 | 138篇 |
出版年
2019年 | 7篇 |
2018年 | 5篇 |
2016年 | 17篇 |
2015年 | 5篇 |
2014年 | 16篇 |
2013年 | 40篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 27篇 |
2007年 | 26篇 |
2006年 | 20篇 |
2005年 | 23篇 |
2004年 | 38篇 |
2003年 | 28篇 |
2002年 | 30篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1973年 | 10篇 |
1972年 | 4篇 |
1970年 | 7篇 |
1969年 | 5篇 |
1964年 | 3篇 |
排序方式: 共有693条查询结果,搜索用时 31 毫秒
61.
The divalent ruthenium complexes bearing benzene, mesitylene triphenylbenzene as a π-ligand were prepared and their catalytic activity for olefin hydrogenation was examined. They showed activity in the presence of a small amount of base. Particularly, the complex with triphenylbenzene was found to have extremely high activity. Discussion here is on a role of a π-arene ligand in the activity. 相似文献
62.
63.
Karataev P Araki S Hamatsu R Hayano H Muto T Naumenko G Potylitsyn A Terunuma N Urakawa J 《Physical review letters》2004,93(24):244802
An experiment on the investigation of optical diffraction radiation (ODR) from a slit target as a possible tool for noninvasive electron beam-size diagnostics has been performed at the KEK accelerator test facility. The experimental setup has been installed at the diagnostics section of the extraction line. We have performed the first incoherent ODR observation from a slit target. The measured angular distributions are in reasonable agreement with the theoretical expectation. The beam-size effect onto the ODR angular pattern has been observed. Moreover, the sensitivity to the beam size as small as 14 microm has been achieved. 相似文献
64.
The hydrodynamic instability of surfactant solutions between two coaxial cylinders was investigated by using a laser-induced-fluorescence flow visualization technique to clarify the effect of drag-reducing additives on vortex formation in Taylor-Couette flow. The test fluids were Ethoquad O/12 surfactant solutions, which have a gel-like structure called “shear-induced structurer” (SIS). Photographs of the formation of Görtler vortices were taken and compared with these of tap water. In the Taylor number range of 1.2×105≤Ta≤7.1×105, tap water and 10 ppm surfactant solution flows consisted of Taylor vortices and much smaller Görtler vortices at the rotating inner wall. However, for 50 and 100 ppm surfactant solutions, Taylor vortices were not apparent and Görtler vortices were collapsed. Measurements of the wavelength of Görtler vortices lead to the conclusion that surfactant solutions have a stabilizing effect on Görtler instabilities. This effect depends on surfactant concentration and becomes considerable with increasing acceleration of the inner cylinder. 相似文献
65.
T. Yabe C. Phipps K. Aoki M. Yamaguchi R. Nakagawa C. Baasandash Y. Ogata M. Shiho G. Inoue M. Onda K. Horioka I. Kajiwara K. Yoshida 《Applied Physics A: Materials Science & Processing》2003,77(2):243-249
Laser-supported propulsion of a micro-airplane with a water-covered ablator is demonstrated. The repetitive use of an overlay
structure is experimentally demonstrated with a specially designed water supply. Various transparent overlays are investigated
by the CIP-based hydrodynamic code and by experiments using a pendulum and using a semi-conductor load cell. A momentum-coupling
efficiency of ∼104 N s/MJ is achieved by water–exotic-target experiments, in agreement with the simulation code, which predicts a maximum efficiency
of ∼105 N s/MJ. The concept of laser-supported propulsion can also be used for driving a Mach 5 airplane in the stratosphere, a micro-ship
inside the human body, and a robot in a nuclear power reactor accident, during which large numbers of neutrons make electronic
devices useless.
Received: 7 October 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +81-3/5734-2165, E-mail: yabe@mech.titech.ac.jp 相似文献
66.
67.
Masakazu Yoshikawa Takashi Yukoshi Kohei Sanui Naoya Ogata 《Journal of polymer science. Part A, Polymer chemistry》1986,24(7):1585-1597
Separation of water–ethanol mixture through a membrane was carried out by pervaporation using a membrane which provided a hydrogen-bonding interaction. A membrane obtained from poly(acrylic acid-co-acrylonitrile) was effective for a selective separation of water from aqueous ethanol solution by pervaporation technique. Spectroscopic and flux analyses verified that this high selectivity toward water was attributed to the hydrogen-bonding interaction between water and acrylic acid (carboxylic acid) unit in the membrane. On the other hand, a membrane from poly(acrylic acid-co-styrene) preferentially permeated ethanol in the low water feed concentration region. 相似文献
68.
Hiroshi Oki Ichiro Oura Tatsuhito Nakamura Kenichi Ogata Shin-ichi Fukuzawa 《Tetrahedron: Asymmetry》2009,20(18):2185-2191
A series of diphosphine ClickFerrophos ligands (CF), based on a triazoleferrocene backbone, was synthesized in a four-step sequence via click chemistry methodology. In addition to the four previously synthesized ligands CF1, CF4, CF7 and CF10, six novel CF ligands CF2–3 and CF5–8 were prepared. Hydrogenation reactions of alkenes and ketones were significantly improved upon by using CF ligands as rhodium- or ruthenium-complexes in which the % ee values can be optimized by choosing the appropriate CF ligand depending on the substrate. 相似文献
69.
Akitoshi Ogata 《Tetrahedron letters》2008,49(19):3071-3074
Titanocene(II)-promoted alkenylation of functionalized alkynes with (Z)-alkenyl sulfones proceeded with high regio- and stereoselectivity to produce functionalized dienes. Conjugated dienylcarboxylic acids and dienylphosphonic esters were obtained using acetylenic lithium carboxylates and dialkyl phosphonates as starting materials. 相似文献
70.
Sakae Tsuda 《Colloid and polymer science》1928,45(4):325-331
Ohne Zusammenfassung 相似文献