全文获取类型
收费全文 | 601篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
化学 | 482篇 |
晶体学 | 6篇 |
力学 | 14篇 |
数学 | 47篇 |
物理学 | 62篇 |
出版年
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 3篇 |
2013年 | 28篇 |
2012年 | 18篇 |
2011年 | 26篇 |
2010年 | 7篇 |
2009年 | 13篇 |
2008年 | 26篇 |
2007年 | 18篇 |
2006年 | 30篇 |
2005年 | 28篇 |
2004年 | 29篇 |
2003年 | 20篇 |
2002年 | 31篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1983年 | 6篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 11篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1961年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有611条查询结果,搜索用时 0 毫秒
1.
Optical Review - This paper demonstrates a method to estimate the depth of a fluorescence object in turbid media using dual-wavelength excited photodynamic diagnosis, to aid in the invasion depth... 相似文献
2.
Cellulose derivative resin (CDR) suspensions containing resin particles of cellulose nitrate (CDR(CN)), cellulose acetate (CDR(CA)), or cellulose triacetate (CDR(CTA)) were prepared as the sorbent for resin suspension injection (RSI) electrothermal atomic absorption spectrometry (ETAAS), in which fine resin particles holding a desired trace element were directly injected into the graphite tube as the suspension. To compare the sorption ability, the distribution ratios of the Mo(VI)-phenylfluorone complex were measured between the aqueous phase and the sorbents, including the CDRs mentioned above and the finely divided anion exchange resin (AR). The results showed that the sorption ability decreases in the following order: CDR(CN) > or = AR > CDR(CA) > or = CDR(CTA). It was concluded that CDR(CN) was able to extract more than 98% of Mo(VI), and was suitable for RSI-ETAAS as well as AR. CDR(CN) was used for the determination of Mo in NIES certified reference materials, No. 10 Rice flour-unpolished; the results showed fairly good agreements between the analytical values and the certified values. 相似文献
3.
An InGaAs/InAlAs five-layer asymmetric coupled quantum well (FACQW) is expected to show very large electrorefractive index change. n in a wideband transparency region. Band structures of the FACQW are analyzed with Luttinger-Kohn Hamiltonian. The electrorefractive characteristics of the FACQW are discussed. 相似文献
4.
13C NMR studies showed that the population of the norcaradiene form of the title systems containing p-CH3O, H, and p-CF3 on the 7-aryl group increases in this order. The result is consistent with the prediction from the π-acceptor strength of the aryl group estimated by INDO calculations. 相似文献
5.
Andrzej Skowronski Kunio Yamagata 《Proceedings of the American Mathematical Society》2004,132(3):659-667
We prove that a large class of self-injective algebras of tilted type is invariant under stable equivalences of module categories.
6.
7.
8.
Interactions between poly(amidoamine) dendrimer (PAMAM)-gold nanocomposites and alkanethiols and between the former nanocomposites and thiol-modified poly(amidoamine) dendrons in ethyl acetate were investigated by adding alkanethiols, such as 1-propanethiol and 1,3-propanedithiol, and thiol-modified poly(amidoamine) dendrons, generations 0.5 and 2.5 (G0.5-SH and G2.5-SH). The PAMAM dendrimers with surface methyl ester groups used were generations 1.5 and 5.5 (G1.5 and G5.5). The mean particle sizes of PAMAM-gold nanocomposites were about 2.1 for G1.5 and 2.4 nm for G5.5. In both nanocomposite systems where 1-propanethiol and 1,3-propanedithiol were added, the mean particle size was about 4 nm, twice that of the systems where these thiols were not added. Increasing the addition of 1,3-propanedithiol made the average particle size smaller for both nanocomposites systems. To compare with alkanethiol, thiol-modified poly(amidoamine) dendron with a highly branched structure on one side was synthesized. Using G2.5-SH as a protective agent, dendron-gold nanocomposites with mean diameters of 3 to 4 nm were obtained. The difference in particle size was seen only when the combination of PAMAM-gold nanocomposites and thiol-modified dendron was less sterically dense, modified dendron (G0.5-SH). The mechanisms for morphology changes in the dendrimer-gold nanocomposites by the addition of these thiols are discussed. 相似文献
9.
A simple and selective route to the Strychnos framework containing 19,20-double bond has been developed employing the thio-Claisen rearrangement. 相似文献
10.
Abstract— The chromophore of the visual pigment of the fruit fly Drosophila melanogaster was studied by high-pressure liquid chromatography (HPLC). Oxime derivatives of the chromophore were successfully analyzed with a more polar solvent than has been used for retinaloximes. A preceding monochromatic irradiation resulted in reversible interchanges in the amount among geometric isomers of the oximes that reflected the photointerconversion of rhodopsin and metarhodopsin of the peripheral photoreceptors (Rl-R6). Authentic all- trans -3-h-ydroxyretinal was used to identify the chromophore from metarhodopsin. Results demonstrated that the chromophore of the visual pigment in Drosophila is 3-h-ydroxyretinal as was proposed in larger flies. 相似文献