全文获取类型
收费全文 | 146篇 |
免费 | 16篇 |
专业分类
化学 | 100篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 29篇 |
物理学 | 13篇 |
无线电 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 12篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 12篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1939年 | 1篇 |
1931年 | 1篇 |
排序方式: 共有162条查询结果,搜索用时 31 毫秒
41.
The synthesis of bifunctional dinuclear platinum complexes, [{PtCl(dach)}(2)-mu-Y](n+)Cl(n) (1-3; Y = H(2)N(CH(2))(3)NH(2)(CH(2))(4)NH(2), H(2)N(CH(2))(6)NH(2)(CH(2))(6)NH(2), and H(2)N(CH(2))(6)NH(2)(CH(2))(2)NH(2)(CH(2))(6)NH(2), respectively; Figure 1) is reported. There was no labilization of the polyamine linker groups of the cis-1,2-diaminocyclohexane complexes in the presence of sulfur-containing species at physiological pH, in contrast to previous studies preformed on trans complexes. Metabolism reactions are somewhat dependent on the nature of the polyamine: at physiological pH, the spermidine complex 1 forms an inert (tetraamine)platinum species in which one platinum is chelated by a central and terminal amino group. The stability of cis-geometry complexes may make them viable second-generation polynuclear platinum clinical candidates. 相似文献
42.
We derive an integral representation for the subelliptic heat kernel of the complex anti-de Sitter fibration. Our proof is different from the one used in Wang (Potential Anal 45:635–653, 2016) since it appeals to the commutativity of the D’Alembertian and of the Laplacian acting on the vertical variable rather than the analytic continuation of the heat semigroup of the real hyperbolic space. Our approach also sheds the light on the connection between the sub-Laplacian of the above fibration and the so-called generalized Maass Laplacian, and on the role played by the odd dimensional real hyperbolic space. 相似文献
43.
Semigroup Forum - Let $${mathscr {C}}! om $$ denote the variety of all commutative semigroups. For $$nge 1$$ let $${{mathscr {N}}! il }_n$$ (respectively $${mathscr {N}}_n$$ ) denote the... 相似文献
44.
Dr. Ki-Young Lee Dr. Zhenhao Fang Dr. Masahiro Enomoto Dr. Genevieve Gasmi-Seabrook Le Zheng Prof. Shohei Koide Prof. Mitsuhiko Ikura Dr. Christopher B. Marshall 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):11130-11138
KRAS homo-dimerization has been implicated in the activation of RAF kinases, however, the mechanism and structural basis remain elusive. We developed a system to study KRAS dimerization on nanodiscs using paramagnetic relaxation enhancement (PRE) NMR spectroscopy, and determined distinct structures of membrane-anchored KRAS dimers in the active GTP- and inactive GDP-loaded states. Both dimerize through an α4–α5 interface, but the relative orientation of the protomers and their contacts differ substantially. Dimerization of KRAS-GTP, stabilized by electrostatic interactions between R135 and E168, favors an orientation on the membrane that promotes accessibility of the effector-binding site. Remarkably, “cross”-dimerization between GTP- and GDP-bound KRAS molecules is unfavorable. These models provide a platform to elucidate the structural basis of RAF activation by RAS and to develop inhibitors that can disrupt the KRAS dimerization. The methodology is applicable to many other farnesylated small GTPases. 相似文献
45.
Bonneau AL Robert N Hoarau C Baudoin O Marsais F 《Organic & biomolecular chemistry》2007,5(1):175-183
The synthesis of three novel racemic phenylpyridine-carbamate analogues of rhazinilam and their biological evaluation as inhibitors of microtubule assembly and disassembly by interaction with tubulin are described. The sterically hindered ortho-disubstituted biaryl unit as the challenging key structural element is first obtained by a sequential regiocontrolled nucleophilic addition of a lithium ortho-lithiohomobenzylic alkoxide species to 3-bromo-5-oxazolyl pyridine as the electrophile and a subsequent oxidation step. The incorporation of the amino group by replacement of the bromide has been achieved using a Buchwald-Hartwig amination coupling. Ultimate deprotection steps furnished free-amino and free-hydroxyl appendages which were connected by phosgenation to furnish the nine-membered median carbamate ring. 相似文献
46.
Baudoin O 《Chemical Society reviews》2011,40(10):4902-4911
Transition-metal-catalyzed C-H bond arylation has recently emerged as a powerful tool for the functionalization of organic molecules that may complement or even replace traditional catalytic cross-couplings. While many efforts have focused on the arylation of arenes and heteroarenes in the past two decades, less studies have been devoted to the arylation of nonacidic C-H bonds of alkyl groups. This tutorial review highlights recent work in this active area. 相似文献
47.
A one-step homogeneous immunoassay for cancer biomarker detection using gold nanoparticle probes coupled with dynamic light scattering 总被引:1,自引:0,他引:1
Liu X Dai Q Austin L Coutts J Knowles G Zou J Chen H Huo Q 《Journal of the American Chemical Society》2008,130(9):2780-2782
A one-step homogeneous immunoassay for the detection of a prostate cancer biomarker, free-PSA (prostate specific antigen), was developed using gold nanoparticle probes coupled with dynamic light scattering (DLS) measurements. A spherical gold nanoparticle with a core diameter around 37 nm and a gold nanorod with a dimension of 40 by 10 nm were first conjugated with two different primary anti-PSA antibodies and then used as optical probes for the immunoassay. In the presence of antigen f-PSA in solution, the nanoparticles and nanorods aggregate together into pairs and oligomers through the formation of a sandwich type antibody-antigen-antibody linkage. The relative ratio of nanoparticle-nanorod pairs and oligomers versus individual nanoparticles was quantitatively monitored by DLS measurement. A correlation can be established between this relative ratio and the amount of antigen in solution. The light scattering intensity of nanoparticles and nanoparticle oligomers is several orders of magnitude higher than proteins and other typical molecules, making it possible to detect nanoparticle probes in the low picomolar concentration range. f-PSA in the concentration range from 0.1 to 10 ng/mL was detected by this one-step and washing-free homogeneous immunoassay. 相似文献
48.
49.
Liu Y Li W Perez T Gunton JD Brett G 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):3-9
We propose a primitive model of Janus ellipsoids that represents particles with an ellipsoidal core and two semisurfaces coded with dissimilar properties, for example, hydrophobicity and hydrophilicity, respectively. We investigate the effects of the aspect ratio on the self-assembly morphology and aggregation processes using Monte Carlo simulations. We also discuss certain differences between our results and those of earlier results for Janus spheres. In particular, we find that the size and structure of the aggregate can be controlled by the aspect ratio. 相似文献
50.