全文获取类型
收费全文 | 138篇 |
免费 | 2篇 |
专业分类
化学 | 105篇 |
力学 | 3篇 |
数学 | 13篇 |
物理学 | 19篇 |
出版年
2021年 | 1篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1997年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1967年 | 1篇 |
1959年 | 1篇 |
1940年 | 1篇 |
1939年 | 2篇 |
1937年 | 1篇 |
1935年 | 4篇 |
1934年 | 4篇 |
1933年 | 2篇 |
1932年 | 1篇 |
1931年 | 3篇 |
1928年 | 3篇 |
1927年 | 3篇 |
1924年 | 4篇 |
1919年 | 1篇 |
1913年 | 2篇 |
排序方式: 共有140条查询结果,搜索用时 46 毫秒
1.
The flat rank of a totally disconnected locally compact group G, denoted flat-rk(G), is an invariant of the topological group
structure of G. It is defined thanks to a natural distance on the space of compact open subgroups of G. For a topological
Kac-Moody group G with Weyl group W, we derive the inequalities alg-rk(W) ≤ flat-rk(G) ≤ rk(|W|0). Here, alg-rk(W) is the maximal Z-rank of abelian subgroups of W, and rk(|W|0) is the maximal dimension of isometrically embedded flats in the CAT0-realization |W|0. We can prove these inequalities under weaker assumptions. We also show that for any integer n ≥ 1 there is a simple, compactly
generated, locally compact, totally disconnected group G, with flat-rk(G) = n and which is not linear. 相似文献
2.
Monika Remy 《manuscripta mathematica》1988,62(3):277-296
For every finite measure space (X,A,P) we find a unique representation P=Q1+Q2+Q3 such that Q1 is compact, Q2 is perfect and purely noncompact and Q3 is purely nonperfect. We show that every Pachl-O-disintegrable probability space is Ramachandran-O-disintegrable and therefore perfect and under a certain condition we prove the equivalence between compactness and Ramachandran-O-disintegrability. 相似文献
3.
D. Giron P. Remy S. Thomas E. Vilette 《Journal of Thermal Analysis and Calorimetry》1997,48(3):465-472
The amorphous state of solids is characterized by a higher chemical and physical reactivity and a hygroscopic behaviour. Furthermore processing of amorphous powders is often difficult, because of the instability. Fast crystallizations, precipitations and milling favour the formation of the amorphous state. Galenical processes like granulation, drying, lyophilization, mixing, may also induce amorphous regions in the drug products.X-ray diffraction techniques can be used for the determination of the amorphicity of drug raw materials or drug products. Unfortunately, 10% is the detection limit, which in normal cases can be attained. Amorphous substances undergo an exothermic crystallization at temperatures above the glass transition point. Water which is a plasticizer decreases the temperature of the glass transition point, allowing the crystallization to occur at lower temperatures. The crystallization energy is measure of by microcalorimetry.Examples show the influence of the choice of the experimental conditions, especially the influence of the amorphicity on the kinetic of the reaction. Critical steps are discussed for three different drug substances. Limits of detection in the magnitude of 1 % are possible using microcalorimetry. 相似文献
4.
A. G. Gagliano † N. E. Geacintov ‡ J. Breton S. Acker R. Remy § 《Photochemistry and photobiology》1979,29(2):415-418
Abstract— The P700 chlorophyll a -protein complex (CPI) isolated from green plants was oriented in aqueous solutions using pulsed electric fields of up to 6700 V cm-1 . The electric linear dichroism spectrum is reported in the range of 400–720nm. Positive peaks in the linear dichroism Δ A = A I - A 1 (where AI and A1 are the absorbance components in which the polarizer orientation is parallel and perpendicular with respect to the electric field. respectively) are observed at 443 and 686 nm. The ΔA signal at 686 nm is discussed in terms of either a specialized chlorophyll form absorbing at 686 nm. or due to an exciton component absorbing at the same wavelength. 相似文献
5.
Codée JD Litjens RE den Heeten R Overkleeft HS van Boom JH van der Marel GA 《Organic letters》2003,5(9):1519-1522
Diphenylsulfoxide in combination with triflic anhydride provides a very potent thiophilic glycosylation promotor system, capable of activating disarmed thioglycosides. The usefulness of this novel thiophilic activator is illustrated in a successful chemoselective glycosylation sequence in which the donor thioglycoside in the first condensation step may be either armed or disarmed. [reaction: see text] 相似文献
6.
Dimerizable cationic detergents with a low cmc condense plasmid DNA into nanometric particles and transfect cells in culture 总被引:4,自引:0,他引:4
The size of condensed DNA particles is a key determinant for in vivo diffusion and gene delivery to cells. Gene molecules can be individually compacted by cationic thiol detergents into nanometric particles that are stabilized by oxidative conversion of the detergent into a gemini lipid. To reach the other goal, gene delivery, a series of cationic thiol detergents with various chain lengths (C(12)-C(16)) and headgroups (ornithine or spermine) was prepared, using a versatile polymer-supported synthetic strategy. Critical micelle concentrations and thiol oxidation rates of the detergents were measured. The formation and stability of complexes formed with plasmid DNA, as well as the size, xi-potential, morphology, and transfection efficiency of the particles were investigated. Using the tetradecane/ornithine detergent, a solution of 5.5 Kpb plasmid DNA molecules was converted into a homogeneous population of 35 nm particles. The same detergent, once oxidized, exhibited a typical lipid phase internal structure and was capable of effective cell transfection. The particle size did not increase with time. Surprisingly, the gel electrophoretic mobility of the DNA complexes was found to be higher than that of plasmid DNA itself. Favorable in vivo diffusion and intracellular trafficking properties may thus be expected for these complexes. 相似文献
7.
Kyle Clagg Sara Hold Archana Kumar Stefan G. Koenig Remy Angelaud 《Tetrahedron letters》2019,60(1):5-7
The direct application of Knochel-Hauser derivative arylmagnesium halides in Kumada-Corriu couplings is described. By utilizing the in situ-generated Grignard reagents, the transmetalation with stoichiometric zinc salts to known Negishi coupling conditions is avoided, thereby streamlining the transformation. Several aromatic hetereocycles participate in the deprotonation and couple with a variety of phenyl iodides and bromides in isolated yields up to 81%. The parent system is demonstrated on 6?g scale with 79% yield, and monitored via ReactIR to show the stability of the Grignard and progression of the deprotonation/CC coupling reaction. 相似文献
8.
9.
Masumi Torii Yuki Hitora Hikaru Kato Yuhei Koyanagi Teppei Kawahara Fitje Losung Remy E.P. Mangindaan Sachiko Tsukamoto 《Tetrahedron》2018,74(52):7516-7521
Four new sulfonated serinol derivatives, siladenoserinols M–P (1–4), were isolated from a tunicate of the family Didemnidae collected in Indonesia. Their chemical structures were elucidated by the interpretation of NMR and mass spectroscopic data. Two of them (2 and 4) were revealed to be disulfonate serinol derivatives, and the others were monosulfonates. Siladenoserinols A (5) and B (6), which we previously isolated from the same tunicate, inhibited the p53–Hdm2 interaction with an IC50 value of 2.0?μM. However, 1–4 did not inhibit the activity. The result suggested that the acetyl group in the bicyclic ketal unit and/or the glycerophospholipid moiety in 5 and 6 were responsible for the inhibition of the p53–Hdm2 interaction. 相似文献
10.
A two-step, one-pot procedure using methyl chloroformate and lithium borohydride was developed to transform 2-substituted-oxazolines into alcohols. This methodology is compatible with a wide range of substrates including heterocyclic, aromatic, and aliphatic functionalized 2-oxazolines. Best results are obtained with electron-rich and ortho substituted 2-aryl-oxazolines. 相似文献