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161.
J. R. Barker L. Brouwer R. Patrick M. J. Rossi P. L. Trevor D. M. Golden 《国际化学动力学杂志》1985,17(9):991-1006
Pulsed laser photolysis of N2O5 near 290 nm coupled with fluorescence detection (calibrated by NO2 photolysis) showed that the O(3P) quantum yield is ≤0.1. A pulsed laser optoacoustic technique in a flow tube (ca. 6 torr of N2) was tested by photolysis of NO2 and then applied to N2O5. Nitric oxide was added to react with NO3 free radical and the resulting increase in the optoacoustic signal confirmed the presence of NO3 free radicals. Based on the relative optoacoustic signals observed for NO2 and N2O5, the quantum yield for NO3 production is 0.8 ± 0.2. 相似文献
162.
The average downward collisional energy transfer (<ΔEdown>) is obtained for highly vibrationally excited tert-butyl chloride, both undeuterated and per-deuterated, with Kr, N2, CO2, and C2H4 bath gases, at ca. 760 K. Data are obtained using the technique of pressure-dependent very low-pressure pyrolysis. Reactant internal energies to which the data are sensitive are in the range 200–250 kJ mol?1. For C4H9Cl, the <ΔEdown> values (cm?1) are 255 (Kr), 265 (N2), 440 (CO2), and 585 (C2H4), and for C4D9Cl, 245 (N2), 370 (CO2), and 540 (C2H4). The uncertainties in these values are ca. 20% (40% for Kr); the uncertainties in the deuteration ratios are 10–15%. The value for Kr is in agreement with theoretical predictions of a biased random walk model for internal energy change in monatomic/substrate collisions. The effect of deuteration of <ΔEdown> is also in accord with that predicted by a modification of the theory. Extrapolated highpressure rate coefficients for the thermal decomposition of reactant are 1013.6 exp(-187 kJ mol?1/RT) s?1 (C4H9Cl) and 1014.2 exp(?196 kJ mol?1/RT) s?1 (C4D9Cl), in accord with other studies and the expected isotope effect. 相似文献
163.
David E. Jackson Barrie W. Bycroft Trevor J. King 《Journal of computer-aided molecular design》1989,2(4):321-328
Summary X-ray crystallographic studies on synthetic DL-quisqualic acid and the corresponding carbon analogue have revealed pyramidal and almost planar geometries respectively for the ring nitrogen atoms carrying the alkyl side chain. Semi-empirical molecular orbital calculations on methyl-substituted model systems predict ring geometries in close agreement with experimentally observed data. The calculated energy barriers between the two enantiomeric forms (invertomers) of the oxadiazolidine systems along with some physical data would suggest that such forms are rapidly interconverting.Deceased. 相似文献
164.
Esteban Aramendia María J. Barandiaran Jos C. De La Cal Jo Grade Trevor Blease Jos M. Asua 《Journal of polymer science. Part A, Polymer chemistry》2004,42(17):4202-4211
The mechanisms by which a new nonionic alkenyl‐based surfmer (Maxemul 5011?) was involved in acrylic emulsion polymerization were investigated. No proof of homopolymerization or of chain transfer to surfmer was obtained under the conditions studied. The effect of the initiator type, feeding time of the surfmer, particle size of the seed, and surfmer concentration, on kinetics and surfmer incorporation showed that the surfmer reacted mainly by copolymerization with the monomers in the outer shell of the polymer particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4202–4211, 2004 相似文献
165.
Using a combination of nmr techniques, the structure of the acetylation product of methyl 3-[2-amino-3-cyano-9-methoxy-4H-5,6-dihydronaphtho[1,2-b]pyran-4-yl] benzoate 2b has been shown to be the N-acetyl derivative 5a , rather than the rearranged 2-acetoxydihydropyridine 6a. 相似文献
166.
Dr. Amit Kumar Dr. Trevor Janes Dr. Noel Angel Espinosa‐Jalapa Prof. David Milstein 《Angewandte Chemie (International ed. in English)》2018,57(37):12076-12080
The first example of a homogeneous catalyst based on an earth‐abundant metal for the hydrogenation of organic carbonates to methanol and alcohols is reported. Based on the mechanistic investigation, which indicates metal‐ligand cooperation between the manganese center and the N?H group of the pincer ligand, we propose that the hydrogenation of organic carbonates to methanol occurs via formate and aldehyde intermediates. The reaction offers an indirect route for the conversion of CO2 to methanol, which coupled with the use of an earth abundant catalyst, makes the overall process environmentally benign and sustainable. 相似文献
167.
Trevor Alan Welsh 《Czechoslovak Journal of Physics》1996,46(2-3):283-291
In this paper, we initiate a study into the explicit construction of irreducible representations of the Hecke algebraH
n
(q) of typeA
n-1
in the non-generic case whereq is a root of unity. The approach is via the Specht modules ofH
n
(q) which are irreducible in the generic case, and possess a natural basis indexed by Young tableaux. The general framework in which the irreducible non-genericH
n
(q)-modules are to be constructed is set up and, in particular, the full set of modules corresponding to two-part partitions is described. Plentiful examples are given.Presented at the 4th International Colloquium Quantum Groups and Integrable Systems, Prague, 22–24 June 1995. 相似文献
168.
169.
Electrocatalysis at graphite and carbon nanotube modified electrodes: edge-plane sites and tube ends are the reactive sites 总被引:3,自引:0,他引:3
Banks CE Davies TJ Wildgoose GG Compton RG 《Chemical communications (Cambridge, England)》2005,(7):829-841
Carbon, and particularly graphite in its various forms, is an attractive electrode material. Two areas of particular interest are modified carbon electrodes and carbon nanotube electrodes. In this article we focus on the relationship between surface structure and electrochemical and chemical reactivity of electrodes based on these materials. We overview recent work in this area which has led us to believe that much of the catalytic activity, electron transfer and chemical reactivity of graphitic carbon electrodes is at surface defect sites, and in particular edge-plane-like defect sites. We also question the claimed special "catalytic" properties of carbon nanotube modified electrodes. 相似文献
170.
Trevor M. Letcher Ma?gorzata Marciniak 《The Journal of chemical thermodynamics》2005,37(12):1327-1331
The activity coefficients at infinite dilution, (where 1 refers to the solute and 3 to the solvent), for both polar and non-polar solutes (alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, benzene, carbon tetrachloride, and methanol) in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide [HMIM][Tf2N] at three temperatures T = (298.15, 313.15, and 333.15) K have been determined by gas-liquid chromatography. The interaction at the gas-liquid interface between the solutes and the solvent was examined by varying solvent liquid loading on the column. Corrected retention values, taking carrier gas and solute imperfections into account, were determined and used to calculate the activity coefficients at infinite dilution. The results have been used to predict the solvent potential for the hexane/benzene separation from calculated selectivity values. The results were compared to for similar systems found in the literature in an attempt to understand the effect of the nature of the cation and anion has on solute-solvent interactions.The partial molar excess enthalpies at infinite dilution values were calculated from the experimental values obtained over the temperature range. 相似文献