全文获取类型
收费全文 | 791篇 |
免费 | 13篇 |
国内免费 | 5篇 |
专业分类
化学 | 628篇 |
晶体学 | 7篇 |
力学 | 10篇 |
数学 | 49篇 |
物理学 | 115篇 |
出版年
2022年 | 4篇 |
2019年 | 5篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 52篇 |
2012年 | 42篇 |
2011年 | 35篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 35篇 |
2007年 | 39篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 41篇 |
2003年 | 30篇 |
2002年 | 27篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 20篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 18篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1978年 | 7篇 |
1977年 | 14篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 8篇 |
1970年 | 3篇 |
1967年 | 4篇 |
1960年 | 3篇 |
1930年 | 4篇 |
排序方式: 共有809条查询结果,搜索用时 15 毫秒
51.
52.
[reaction: see text] Radical cascade reaction with various 1,4-dienes and 1,4-enynes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate as a homoallyl radical precursor smoothly proceeds through an iodine atom transfer mechanism to give functionalized bicyclo[3.3.0]octane derivatives in good yields. 相似文献
53.
Visible photoluminescence (PL) of nanocrystalline silicon (nc-Si) embedded in single crystal CaF2 formed on Si(1 1 1) has been studied and the influence of ex situ rapid thermal annealing (RTA) on the surface morphology and PL spectra has been studied. It has been found that the PL intensity and uniformity was improved by RTA with appropriate temperature and short annealing time. 相似文献
54.
Munetaka Nakata Masaaki Sugie Harutoshi Takeo Chi Matsumura Tsutomu Fukuyama Kozo Kuchitsu 《Journal of Molecular Spectroscopy》1981,86(1):241-249
The microwave spectra of four isotopic species of dichlorine monoxide (OCl2) have been observed, and the rotational constants have been obtained. The rm structure for each isotopic species has been determined by Watson's method. The equilibrium structure has been estimated by taking proper averages of rm structures to be and ∠eClOCl = 110.886(6)°. The general applicability and the merit of the present method for estimating the equilibrium structure are pointed out. 相似文献
55.
56.
Both abilities of germination of spores formed after UV irradiation and of growth of amoeboid cells emerged from the spores were studied on two kinds of Dictyostelium discoideum strains, NC-4 and ys-13.
An inhibition of germination was observed on the spores of ys -13 when formed after UV irradiation, while no inhibition was detected on the ability of germination of spores of NC-4. The amoeboid cells of ys -13 emerged from the spores showed a heavy delay of growth, although no delay of growth was detected even on the amoeboid cells of NC-4 emerged from the spores formed after UV irradiation. The strain of NC-4 must repair UV lesions fully before spore formation, while the spores of ys-13 must keep some UV lesions unrepaired and send them to the next generation of amoeboid cells. The characters of UV lesion inheritable through the spores to the next amoeboid cells in ys-13 were discussed. 相似文献
An inhibition of germination was observed on the spores of ys -13 when formed after UV irradiation, while no inhibition was detected on the ability of germination of spores of NC-4. The amoeboid cells of ys -13 emerged from the spores showed a heavy delay of growth, although no delay of growth was detected even on the amoeboid cells of NC-4 emerged from the spores formed after UV irradiation. The strain of NC-4 must repair UV lesions fully before spore formation, while the spores of ys-13 must keep some UV lesions unrepaired and send them to the next generation of amoeboid cells. The characters of UV lesion inheritable through the spores to the next amoeboid cells in ys-13 were discussed. 相似文献
57.
Takeo Ojika 《Journal of Mathematical Analysis and Applications》1980,73(1):192-203
A natural interpretation of “maj” and “inv” q-counting of multiset permutations in terms of walks on a lattice with multilane highways is presented. This is applied to give a short combinatorial proof of two theorems of MacMahon and to rederive a recent result of Gessel. 相似文献
58.
59.
60.
In this paper we give a proof for convergence of the initial value adjusting method, described in detail in part I, based on Kantorovich's theorem. Under standard assumptions on the dynamics, boundary conditions, and initial approximations, a quadratic convergence rate is obtained. 相似文献