全文获取类型
收费全文 | 244篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学 | 133篇 |
晶体学 | 3篇 |
力学 | 16篇 |
数学 | 41篇 |
物理学 | 64篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 13篇 |
2012年 | 20篇 |
2011年 | 19篇 |
2010年 | 9篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 15 毫秒
51.
Tetrazole Photoclick Chemistry: Reinvestigating Its Suitability as a Bioorthogonal Reaction and Potential Applications 下载免费PDF全文
Dr. Zhengqiu Li Linghui Qian Prof. Dr. Lin Li Dr. Jan C. Bernhammer Prof. Dr. Han Vinh Huynh Prof. Dr. Jun‐Seok Lee Prof. Dr. Shao Q. Yao 《Angewandte Chemie (International ed. in English)》2016,55(6):2002-2006
The bioorthogonality of tetrazole photoclick chemistry has been reassessed. Upon photolysis of a tetrazole, the highly reactive nitrile imine formed undergoes rapid nucleophilic reaction with a variety of nucleophiles present in a biological system, along with the expected cycloaddition with alkenes. The alternative use of the tetrazole photoclick reaction was thus explored: tetrazoles were incorporated into Bodipy and Acedan dyes, providing novel photo‐crosslinkers with one‐ and two‐photon fluorescence Turn‐ON properties that may be developed into protein‐detecting biosensors. Further introduction of these photo‐activatable, fluorogenic moieties into staurosporine resulted in the corresponding probes capable of photoinduced, no‐wash imaging of endogenous kinase activities in live mammalian cells. 相似文献
52.
In the present paper, we are interested in the propagation of Rayleigh waves in an isotropic elastic half-space coated with a thin isotropic elastic layer. The contact between the layer and the half space is assumed to be smooth. The main purpose of the paper is to establish an approximate secular equation of the wave. By using the effective boundary condition method, an approximate, yet highly accurate secular equation of fourth-order in terms of the dimensionless thickness of the layer is derived. From the secular equation obtained, an approximate formula of third-order for the velocity of Rayleigh waves is established. The approximate secular equation and the formula for the velocity obtained in this paper are potentially useful in many practical applications. 相似文献
53.
Vinh NB Simpson JS Scammells PJ Chalmers DK 《Journal of computer-aided molecular design》2012,26(4):409-423
We have used virtual screening to develop models for the binding of aryl substituted heterocycles to p38α MAPK. Virtual screening
was conducted on a number of p38α MAPK crystal structures using a library of 46 known p38α MAPK inhibitors containing a heterocyclic
core substituted by pyridine and fluorophenyl rings (structurally related to SB203580) and a set of decoy compounds. Multiple
protonation states and tautomers of active and decoy compounds were considered. Each docking model was evaluated using receiver
operating characteristic (ROC) curves and enrichment factors. The two best performing single crystal structures were found
to be 1BL7 and 2EWA, with enrichment factors of 14.1 and 13.0 at 2 % of the virtual screen respectively. Ensembles of up to
four receptors of similar conformations were generated, generally giving good or very good performances with high ROC AUCs
and good enrichment. The 1BL7-2EWA ensemble was able to outperform each of its constituent receptors and gave high enrichment
factors of 17.3, 12.0, 8.0 at 2, 5 and 10 % respectively, of the virtual screen. A ROC AUC of 0.94 was obtained for this ensemble.
This method may be applied to other proteins where there are a large number of inhibitor classes with different binding site
conformations. 相似文献
54.
Shahali Y Sutra JP Haddad I Vinh J Guilloux L Peltre G Sénéchal H Poncet P 《Electrophoresis》2012,33(3):462-469
Italian cypress (Cupressus sempervirens, Cups) pollen causes allergic diseases in inhabitants of many of the cities surrounding the Mediterranean basin. However, allergens of Cups pollen are still poorly known. We introduce here a novel proteomic approach based on double one‐dimensional gel electrophoresis (D1‐DE) as an alternative to the 2‐DE immunoblot, for the specific IgE screening of allergenic proteins from pollen extracts. The sequential one‐dimensional combination of IEF and SDS‐PAGE associated with IgE immunoblotting allows a versatile multiplexed immunochemical analysis of selected groups of allergens by converting a single protein spot into an extended protein band. Moreover, the method appears to be valuable for MS/MS identification, without protein purification, of a new Cups pollen allergen at 43 kDa. D1‐DE immunoblotting revealed that the prevalence of IgE sensitization to this allergen belonging to the polygalacturonase (PG) family was 70% in tested French allergic patients. In subsequent triple one‐dimensional gel electrophoresis, the Cups pollen PG was shown to promote lectin‐based protein‐protein interactions. Therefore, D1‐DE could be used in routine work as a convenient alternative to 2‐DE immunoblotting for the simultaneous screening of allergenic components under identical experimental conditions, thereby saving considerable amounts of sera and allergen extracts. 相似文献
55.
Controlling the Spontaneous Precipitation of Silver Nanoparticles in Sol-Gel Materials 总被引:1,自引:0,他引:1
Wu Pu-Wei Dunn Bruce Doan Vinh Schwartz Benjamin J. Yablonovitch Eli Yamane Masayuki 《Journal of Sol-Gel Science and Technology》2000,19(1-3):249-252
The mechanisms responsible for spontaneous silver precipitation in silver-doped sol-gel materials are identified. The chemistry of the solvent phase is found to be the critical factor in controlling this phenomenon. The addition of HCl as catalyst leads to the formation of AgCl and subsequent formation of silver upon light exposure. Another factor leading to silver precipitation is the reducing capability of methanol radicals. Silver precipitation is inhibited by simply washing out the pore solvents by a solvent exchange method. 相似文献
56.
Ngoc Vinh Huynh Thi Hoai Thu Nguyen Kim Phi Phung Nguyen Poul Erik Hansen 《Magnetic resonance in chemistry : MRC》2013,51(7):439-443
Tithonia tagetiflora Desv. (Asteraceae) is a widespread plant in Vietnam, and the species of Tithonia are known as plants containing many biologically active compounds. However, T. tagetiflora's chemical composition remains mostly unknown. Therefore, we now report the structural elucidation of two new sesquiterpene lactones, 8‐angeloyloxy‐2,14‐epoxygermacra‐4,10(1),11(13)‐trien‐6,12‐olide (1) and 6‐angeloyloxy‐1‐hydroxy‐3,4‐epoxygermacra‐9,11(13)‐dien‐8,12‐olide (2), together with three known compounds, including two norisoprenoids, (6S,9S)‐vomifoliol or (6R,9R)‐vomifoliol (3) and (6S,9S)‐roseoside (4), and one glutinane type triterpene, epi‐glutinol (5), from the leaves of T. tagetiflora. Their structures are established by 1D and 2D NMR spectroscopy, as well as ESI‐MS analysis and comparison with literature data. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
57.
Ha Vinh Tan 《Czechoslovak Journal of Physics》1985,35(1):72-85
The polarization properties cf second order nonlinear acousto-optical effect in semiconductors are investigated by the symmetry consideration. The scattering tensor of the process is derived in terms of the Clebsh-Gordon coefficients of the crystalline symmetry group. As an example a semiconductor with zinc-blende structure is studied.The author would like to thank Professor Hguyen Van Hieu for suggesting the problem and and for fruitful discussions. 相似文献
58.
The continuous element method is presented in the context of the harmonic response of beam assemblies. A general formulation is described from the displacement solution of the elementary problem. A direct computation of elementary dynamic stiffness matrices is presented. In the present formulation, distributed loadings are taken into account. In the case of more complex geometries for which many coupling phenomena occur, an explicit formulation is no more conceivable. In this case, a numerical approach is presented. This approach allows an algorithmic computation of exact dynamic stiffness matrices. This method, called “Numerical Continuous Element”, allows one to consider the coupled vibrations of curved beams and those of helical beams. The validation of this numerical method is achieved by comparisons with the harmonic response of various beams obtained by a finite element approach. Finally, a comparison between eigenfrequencies obtained experimentally and numerically for a straight beam and a helical beam has been made to evaluate the performances of the method. 相似文献
59.
Ph(C2)CH2Cl and Ph(C2)'CO2Na [where (C2) = -C=C- or trans-CH=CH-, (C2)' = -C=C- or cis-CH=CH-] reacted in refluxing dimethylformamide to yield unsaturated esters Ph(C2)'CO2-CH2(C2)Ph and/or their intramolecular Diels-Alder cyclization products (cyclolignan lactones). It was found that modal selectivity for cyclization in DMF sometimes varies from that found previously with acetic anhydride as solvent. Two new parent tetrahydrocyclolignan lactones were synthesized. 相似文献
60.