全文获取类型
收费全文 | 140篇 |
免费 | 2篇 |
专业分类
化学 | 76篇 |
晶体学 | 6篇 |
力学 | 5篇 |
数学 | 20篇 |
物理学 | 35篇 |
出版年
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2013年 | 17篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 1篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有142条查询结果,搜索用时 31 毫秒
101.
Comparison of δ18O and δ13C values between tree‐ring whole wood and cellulose in five species growing under two different site conditions 下载免费PDF全文
102.
Enaminones are very stable compounds and can be prepared from cheap and easily available starting materials. Therefore they are excellent starting materials in organic synthesis. The selective reduction of ortho-acylated β-enaminones under mild conditions, keeping the enaminone moiety intact, is reported. The appropriated conditions for cyclization of newly obtained hydroxienamides were found. Novel 1-substituted 1,2,3,4-tetrahydroisoquinolines with potential anticonvulsic activity were synthesized. 相似文献
103.
Estimates for the moduli of noncompact convexity of lp-sums and real interpolation spaces for finite families of spaces are given. It is proved that such an interpolation preserves nearly uniform convexity and property (β). 相似文献
104.
The kinetics of dehydration of Al2(SeO3)3·6H2O, Ga2(SeO3)3·6H2O and In2(SeO3)3·6H2O were studied under non-isothermal heating on a derivatograph. The method of Coats-Redfern was used with different kinetics models. The values of the kinetics parameters characterizing the process were calculated. The dependencies observed were interpreted according to the generalized perturbation theory of chemical reactivity. Kinetic compensation effect was found. 相似文献
105.
L.Y Nikolova 《Journal of Mathematical Analysis and Applications》2003,283(2):549-556
We show how uniform convexity can be preserved in the logarithmic spaces Aθ(logA)b,p. Estimates are given for the moduli of convexity of Aθ(logA)b,p in terms of the moduli of A0 and A1, when one or both of them are uniformly convex. 相似文献
106.
A model for the rate of dissolution in liquid film on horizontal rotating disk is obtained by the method of Leveque. It as
well as models found in the literature are subjected to experimental verification by dissolving disk cast of gypsum in two
liquids. Satisfactory agreement with the model predictions is found. The rate with rotation is compared to that in gravitational
film. Enhancements up to 2.5 times are established. 相似文献
107.
108.
The one‐pot tandem reaction of diethyl coumarin‐3‐phosphonate 1 with a mixture of sodium borohydride/acid anhydrides gives mainly the corresponding hydrogenation/acylation product of diethyl 3‐acyl‐2‐oxochroman‐3‐ylphosphonates 3a–d in good yields. Different experimental conditions have been examined to get the best yields of the reaction products. From this reaction the hydrogenation product of diethyl 2‐oxochroman‐3‐ylphosphonate, 2, as well as the products of the consecutive hydrogenation, diethyl 2‐hydroxychroman‐3‐ylphosphonate (4) and diethyl 3‐[2‐hydroxyphenyl]‐1‐hydroxy‐propan‐2‐ylphosphonate (5), have been isolated. 相似文献
109.
Neli Christova Boryana Tuleva Anton Kril Milka Georgieva Spiro Konstantinov Ivan Terziyski Biliana Nikolova Ivanka Stoineva 《Applied biochemistry and biotechnology》2013,170(3):676-689
A newly isolated indigenous strain BN10 identified as Pseudomonas aeruginosa was found to produce glycolipid (i.e., rhamnolipid-type) biosurfactants. Two representative rhamnolipidic fractions, RL-1 and RL-2, were separated on silica gel columns and their chemical structure was elucidated by a combination of nuclear magnetic resonance and mass spectroscopy. Subsequently, their cytotoxic effect on cancer cell lines HL-60, BV-173, SKW-3, and JMSU-1 was investigated. RL-1 was superior in terms of potency, causing 50 % inhibition of cellular viability at lower concentrations, as compared to RL-2. Furthermore, the results from fluorescent staining analysis demonstrated that RL-1 inhibited proliferation of BV-173 pre-B human leukemia cells by induction of apoptotic cell death. These findings suggest that RL-1 could be of potential for application in biomedicine as a new and promising therapeutic agent. 相似文献
110.
Stela Statkova-Abeghe Plamen A. Angelov Iliyan Ivanov Stoyanka Nikolova Ekaterina Kochovska 《Tetrahedron letters》2007,48(38):6674-6676
A series of cyclic enaminoketones were selectively amidoalkylated at the α-carbon in reactions with acyliminium reagents derived from 3,4-dihydroisoquinolines. 相似文献