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101.
Proteomic profiling of human urine using multi-dimensional protein identification technology 总被引:2,自引:0,他引:2
Ru QC Katenhusen RA Zhu LA Silberman J Yang S Orchard TJ Brzeski H Liebman M Ellsworth DL 《Journal of chromatography. A》2006,1111(2):166-174
Human urine samples are ideal for proteomic profiling and have tremendous potential as sources of biomarkers. Multi-dimensional protein identification technology (MudPIT) is an effective approach to analyzing human urine or other fluids dominated by diverse metabolites. MudPIT analysis was used to identify 87 proteins in just 15 ml of human urine. A high throughput, reproducible, and sensitive technology, MudPIT may soon be used for more proteomic analyses of metabolites. 相似文献
102.
Ru QC Zhu LA Katenhusen RA Silberman J Brzeski H Liebman M Shriver CD 《Journal of chromatography. A》2006,1111(2):175-191
Multi-dimensional protein identification technology (MudPIT) is becoming a prevalent proteomic approach due to its high-throughput separations and accurate mass detection. Prior to MudPIT analysis, complicated samples required in-solution digestion. Unlike in-gel digestion, in which enzymes work on just a few proteins, in-solution digestion involves simultaneous digestion of hundreds or thousands of proteins. In-solution digestion protocols must therefore be very efficient. Few investigations have evaluated the efficiency of in-solution digestion protocols. The present research compared three such protocols. Results suggest that a protocol utilizing trifluoroethanol (TFE) as denaturant is most efficient. 相似文献
103.
The first unequivocal thermochemical/calorimetric determination of the enthalpies of combustion, phase change, and formation of a pair of (E)- and (Z)-disubstituted olefins of the type XCH = CHX, where X is an electron withdrawing group, is reported in this paper for the isomeric species dimethyl fumarate and dimethyl maleate (X = COOCH3). The corresponding density functional calculations, corrected for vibrational and thermal effects, confirm that the former isomer is more stable by some 30 kJ mol-1. 相似文献
104.
It is well established that the ??-bond in the elemental halogens is weak. It is likewise weak in peroxides, disulfides, interhalogens, noble gas monohalide cations, and other isoelectronic species. This is normally explained in terms of lone pair?Clone pair repulsion. Other explanations are given as well. 相似文献
105.
In the current review the content of the journal Structural Chemistry for the calendar year 2010 is related to thermochemistry. To a short summary of each article in this volume of the journal a thermochemical comment is added. 相似文献
106.
Shakeela Jabeen Alexander Greer Kathleen F. Edwards Joel F. Liebman 《Photochemistry and photobiology》2020,96(5):1140-1143
A unique approach is used to relate the HOMO-LUMO energy difference to the difference between the ionization potential (IP) and electron affinity (EA) to assist in deducing not only the colors, but also chromophores in elemental nonmetals. Our analysis focuses on compounds with lone pair electrons and σ electrons, namely X2 (X = F, Cl, Br, I), S8 and P4. For the dihalogens, the [IP – EA] energies are found to be: F2 (12.58 eV), Cl2 (8.98 eV), Br2 (7.90 eV), I2 (6.78 eV). We suggest that the interahalogen X–X bond itself is the chromophore for these dihalogens, in which the light absorbed by the F2, Cl2, Br2, I2 leads to longer wavelengths in the visible by a π → σ* transition. Trace impurities are a likely case of cyclic S8 which contains amounts of selenium leading to a yellow color, where the [IP – EA] energy of S8 is found to be 7.02 eV. Elemental P4 with an [IP – EA] energy of 9.09 eV contains a tetrahedral and σ aromatic structure. In future work, refinement of the analysis will be required for compounds with π electrons and σ electrons, such as polycyclic aromatic hydrocarbons (PAHs). 相似文献
107.
Stefan Perisanu Iulia Contineanu Ana Neacsu Nigam P. Rath James S. Chickos Rafael Notario Joel F. Liebman 《Structural chemistry》2013,24(6):1975-1980
The crystalline and gas phase enthalpy of formation of 5-cyano-7H-dibenzo-[a,c]-cyclohepten-6-amine (1) (142.0 ± 11.6 and 264 ± 20 kJ mol?1, respectively) are reported. The sublimation enthalpy at T = 298.15 K for this compound was evaluated by combining the fusion enthalpy from DSC measurements adjusted to 298 K with estimated vaporization enthalpy. The experimental enthalpy of formation is discussed in relationship with values calculated at the G3(MP2)//B3LYP level of quantum chemical theory and by means of group additivity. The crystal structure of this compound was determined by X-ray crystallography and shown to exist entirely in the cyanoenamine form 1, i.e. not the tautomeric α-cyanoimine 2. 相似文献
108.
David H. Ahlstrom Shirley A. Liebman Kent B. Abbs 《Journal of polymer science. Part A, Polymer chemistry》1976,14(10):2479-2495
A series of polyethylenes (PE), reduced poly(vinyl chlorides), and precursor poly(vinyl chloride) (PVC) systems were studied by pyrolysis–gas chromatography (PGC) and by pyrolysis–hydrogenation–gas chromatography (PHGC). The branch content of these polymers has been interpreted on the basis of previously established literature information. Low-density PE (LDPE) was found to contain a significant number of ethyl branches. The pyrolysis results on an LAH-reduced PVC series gave significant insight on PVC microstructure. It was determined that the short-chain branches in PVC are mainly one carbon long. Some ethyl side chains and virtually no butyl branches were found in this experimental PVC series. The effect of chain branching on the pyrolysis of PVC is to increase fragmentation. The benzene/toluene ratio, along with relative amounts of benzene and naphthalene formed, may be used to indicate the relative degree of branching in this system. The application of PGC and PHGC have thus been shown to successfully extend analytical work on PE and PVC and to provide microstructural information. 相似文献
109.
Structural Chemistry - The contents of issues 1 and 2 of Structural Chemistry from the calendar year 2016 are summarized in the present review. A brief thermochemical commentary and possible... 相似文献
110.
Computed Regioselectivity and Conjectured Biological Activity of Ene Reactions of Singlet Oxygen with the Natural Product Hyperforin 下载免费PDF全文
Inna Abramova Benjamin Rudshteyn Joel F. Liebman Alexander Greer 《Photochemistry and photobiology》2017,93(2):626-631
Hyperforin is a constituent of St. John's wort and coexists with the singlet oxygen sensitizer hypericin. Density functional theory, molecular mechanics and Connolly surface calculations show that accessibility in the singlet oxygen “ene” reaction favors the hyperforin “southwest” and “southeast” prenyl (2‐methyl‐2‐butenyl) groups over the northern prenyl groups. While the southern part of hyperforin is initially more susceptible to oxidation, up to 4 “ene” reactions of singlet oxygen can take place. Computational results assist in predicting the fate of adjacent hydroperoxides in hyperforin, where the loss of hydrogen atoms may lead to the formation of a hydrotrioxide and a carbonyl instead of a Russell reaction. 相似文献