全文获取类型
收费全文 | 201篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
化学 | 155篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 15篇 |
物理学 | 36篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 10篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 16篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 109 毫秒
61.
Paul A. Clemons Angela N. Koehler Bridget K. Wagner Timothy G. Sprigings David R. Spring Randall W. King Stuart L. Schreiber Michael A. Foley 《Chemistry & biology》2001,8(12):1183-1195
BACKGROUND: Chemical genetics provides a systematic means to study biology using small molecules to effect spatial and temporal control over protein function. As complementary approaches, phenotypic and proteomic screens of structurally diverse and complex small molecules may yield not only interesting individual probes of biological function, but also global information about small molecule collections and the interactions of their members with biological systems. RESULTS: We report a general high-throughput method for converting high-capacity beads into arrayed stock solutions amenable to both phenotypic and proteomic assays. Polystyrene beads from diversity-oriented syntheses were arrayed individually into wells. Bound compounds were cleaved, eluted, and resuspended to generate 'mother plates' of stock solutions. The second phase of development of our technology platform includes optimized cleavage and elution conditions, a novel bead arraying method, and robotic distribution of stock solutions of small molecules into 'daughter plates' for direct use in chemical genetic assays. This library formatting strategy enables what we refer to as annotation screening, in which every member of a library is annotated with biological assay data. This phase was validated by arraying and screening 708 members of an encoded 4320-member library of structurally diverse and complex dihydropyrancarboxamides. CONCLUSIONS: Our 'one-bead, multiple-stock solution' library formatting strategy is a central element of a technology platform aimed at advancing chemical genetics. Annotation screening provides a means for biology to inform chemistry, complementary to the way that chemistry can inform biology in conventional ('investigator-initiated') small molecule screens. 相似文献
62.
Clark RJ Foley LJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(7):1389-1393
Photolyses of matrices of either BrCHCHBr/NO2/Ar or ClCHCHCl/NO2/Ar using quartz-filtered radiation (lambda>240 nm) led to the appearance of infrared bands attributable to carbonyl, carbon monoxide, and ketene species; no bands belonging to a precursor complex NO2cdots, three dots, centeredXCHCHX (where X=Br or Cl) were observed upon matrix deposition. The possible reaction pathway is discussed. 相似文献
63.
The variation of the SIMS spectra of Ni(001)c(2 × 2)-CO induced by bombardment of Ar+ primary ions with kinetic energy between 300 and 1200 eV has been examined in detail. The purpose of the study is to examine the influence of primary ion energy on a number of experimental observables and to test the accuracy of classical dynamics calculations for neutral particles in predicting the experimental results for ejected ions. The calculations were performed using two extreme forms of the Ar+ -substrate interaction potential to examine the sensitivity of the results to the parameters that need to be included in the model. We find excellent agreement between the NiCO+/Ni+ ion yield ratio measured between 300–1200 eV Ar+ ion energy and the computational results if the Molière form of the ion-substrate potential is used and if the calculated results are corrected by including an image force. The calculated angular distributions of the ejected particles also agree well with those observed experimentally. From the calculations we see that the extent of CO fragmentation relative to the amount of molecular CO ejection is roughly constant in the 300–1200 eV beam energy range with a slight increase seen at lower (~ 300 eV) energies. The implications of these results are discussed in terms of our ability to study the chemistry and structure of surfaces with SIMS. 相似文献
64.
We report here studies at room temperature of the electrical conductivity of AsF5-graphite, a lamellar intercalation compound. Compounds with composition C8nAsF5 have been synthesized where n is the stage. Preliminary measurements of basal plane electrical conductivities indicating values comparable with OFHC copper have been confirmed. Associated anisotropy ratios are observed for n ≤ 3. Data for both the a-axis and c-axis conductivities as a function of stage for low stage compounds is reported. 相似文献
65.
66.
The isolation and identification of the first examples of anhydrous lanthanide chloride tetraphenylporphyrin complexes have been described. The purple complexes were generated by the reaction of dilithiotetraphenylporphyrin bis(dimethoxyethane) with lanthanide trichloride tris(tetrahydrofuran) salts to yield the products in up to 85% yield. The crystal structures for the holmium and ytterbium complexes are also presented. 相似文献
67.
68.
Dr. Daniel J. Foley M. Sc. Sarah Zinken Dr. Dale Corkery Assist. Prof. Luca Laraia Dr. Axel Pahl Prof. Dr. Yao-Wen Wu Prof. Dr. Herbert Waldmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(30):12570-12576
Pseudo-natural-product (NP) design combines natural product fragments to provide unprecedented NP-inspired compounds not accessible by biosynthesis, but endowed with biological relevance. Since the bioactivity of pseudo-NPs may be unprecedented or unexpected, they are best evaluated in target agnostic cell-based assays monitoring entire cellular programs or complex phenotypes. Here, the Cinchona alkaloid scaffold was merged with the indole ring system to synthesize indocinchona alkaloids by Pd-catalyzed annulation. Exploration of indocinchona alkaloid bioactivities in phenotypic assays revealed a novel class of azaindole-containing autophagy inhibitors, the azaquindoles. Subsequent characterization of the most potent compound, azaquindole-1, in the morphological cell painting assay, guided target identification efforts. In contrast to the parent Cinchona alkaloids, azaquindoles selectively inhibit starvation- and rapamycin-induced autophagy by targeting the lipid kinase VPS34. 相似文献
69.
Luke M. Haverhals Hadley M. Sulpizio Zane A. Fayos Matthew A. Trulove W. Matthew Reichert Matthew P. Foley Hugh C. De Long Paul C. Trulove 《Cellulose (London, England)》2012,19(1):13-22
A systematic study of variables that affect the fiber welding process is presented. Cotton cloth samples are treated with
controlled amounts of 1-ethyl-3-methylimidazolium acetate for a series of times and temperatures. Diluting the ionic liquid
with a volatile molecular co-solvent allows temporal and spatial control of the welding process not possible with neat ionic
liquids. Materials are characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and mechanical
(tensile) testing. Results suggest careful management of process variables permits controlled, reproducible manipulation of
chemical and physical properties. 相似文献
70.
Determination of eleven coccidiostats in animal feed by liquid chromatography-tandem mass spectrometry at cross contamination levels 总被引:1,自引:0,他引:1
A confirmatory multi-residue method has been developed to allow for the detection, confirmation and quantification of eleven coccidiostats in animal feed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method can be used to determine halofuginone, robenidine, nicarbazin, diclazuril, decoquinate, semduramicin, lasalocid, monensin, salinomycin, narasin, maduramicin at levels relating to unavoidable carry over as stated in Regulation 2009/8/EC. Feed samples are extracted with water and acetonitrile with the addition of anhydrous magnesium sulphate and sodium chloride. The extract then undergoes a freezing out step before being diluted and injected onto the LC-MS/MS system. The LC-MS/MS system is run in MRM mode with both positive and negative electrospray ionisation and can confirm all eleven analytes in a run time of 19 min. The sensitivity of the method allows quantification and confirmation for all coccidiostats at a 0.5% carry over level. The method was validated over three days in accordance with of European legislation; Commission Decision 2002/657/EC. Validation criteria of accuracy, precision, decision limit (CCα), and detection capability (CCβ) along with measurement uncertainty are calculated for all analytes. The method was then successfully used to analyse a number of feed samples that contained various coccidiostat substances. 相似文献