全文获取类型
收费全文 | 405篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
化学 | 286篇 |
晶体学 | 9篇 |
力学 | 10篇 |
数学 | 20篇 |
物理学 | 90篇 |
出版年
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 22篇 |
2012年 | 30篇 |
2011年 | 29篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 26篇 |
2004年 | 22篇 |
2003年 | 19篇 |
2002年 | 26篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有415条查询结果,搜索用时 15 毫秒
51.
The basic characteristics of vaporization and flowing behavior of n-pentane injected through a single nozzle into a column of hot water have been studied photographically. Subcools at the nozzle-outlet have a strong influence on the critical temperature driving forces at over which vaporization can be maintained. The length of a Rayleigh jet is remarkably shortened when vaporization occurs, whereas mean diameters of drops are little affected whether vaporization occurs or not. A specific condition that a bubble appears in each drop is satisfied not on a specific line but over a wide region on the ΔT∞ - UN plane. 相似文献
52.
53.
The B1A1 state of SiH2 and SiD2 was observed by the optical-optical double resonance technique for the first time. The electronic band origin of the B state of SiD2 was determined to be 27 214.11 cm(-1). A very clear exclusive behavior depending on the even/odd value of the bending vibrational quantum number was observed in the spectra, representing a quasilinear behavior of the B state. The barrier height to linearity was estimated to be approximately 125 cm(-1) by the quasilinear analysis of the bending vibrational level structure of SiD2. 相似文献
54.
55.
Yozo Chatani Takao Ohno Tadafumi Yamauchi Yasuhiko Miyake 《Journal of Polymer Science.Polymer Physics》1973,11(2):369-388
One of the cyclic oligomers of formaldehyde, 1,3,5,7,9,11-hexoxecane, was found to undergo polymerization in the solid state to form polyoxymethylene both during and subsequent to x- or γ-irradiation. The polymer yield increases with polymerization temperature but decreases drastically near the melting point of the hexoxecane crystal. In order to clarify the specificity of the solid-state polymerization, the crystal structure of hexoxecane was first analyzed; hexoxecane forms a trigonal crystal with cell dimensions of a = b = 7.917 Å, c = 11.345 Å, space group R3 –C3i2, three molecules of 3 symmetry per unit cell. The polyoxymethylene as polymerized from a single crystal of hexoxecane is highly crystalline and the crystallites are definitely oriented with respect to the original crystal. There are three kinds of oriented trigonal polyoxymethylene: i.e., with the polymer chains oriented along the 〈100〉, 〈001〉, and 〈210〉 axes of the hexoxecane crystal. The relative yields of these crystallites depend upon the polymerization temperature. In addition to the ordinary trigonal polyoxymethylene, oriented orthorhombic polyoxymethylene was also found in the case of polymerization during treatment with x-rays. 相似文献
56.
57.
In the dimethyl sulfoxide (DMSO)-metal oxide oxidation of alcohol to carbonyl compound, molybdenum oxides were the only useful catalytic reagents, and various alcohols were oxidized to the corresponding carbonyl compounds in high yields. 相似文献
58.
Here we show, analytically and numerically, that in a TiO(2) double-groove grating with two different groove widths per period attached on the SiO(2) substrate, the normally incident light couples to the +1st-order transmission with 96.9% efficiency and with a 50° diffraction angle that is larger than the SiO(2)-air interface critical angle. Modal analysis reveals that three propagating modes for the +1st diffraction order reach the grating back end in phase, while the corresponding propagating modes for the -1st and zeroth orders are added destructively at the grating end. Four optical devices based on this grating characteristic are numerically demonstrated. 相似文献
59.
We determine the necessary and sufficient conditions for the based SU(l)-instanton moduli spaces over CP2 and the unbased SU(2)-instanton moduli spaces over S4 having spin structures. 相似文献
60.
Yumiko Sano Keishi Kato Masaaki Yokoyama Yasuhiko Shirota Hiroshi Mikawa 《Molecular Crystals and Liquid Crystals》2013,570(1-2):137-141
Glass-forming properties of 2-pyrazoline derivatives were examined and discussed in terms of the molecular structure. The results show that the molecular shape of 1,3,5-triaryl-2-pyrazolines is responsible for the glass-forming properties of these compounds. Glass transition points of several 1,3,5-triaryl-2-pyrazoline derivatives were measured. 相似文献