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991.
992.
Vera Yu. Petukhova Leonid L. Fershtat Vadim V. Kachala Vladimir V. Kuznetsov Dmitriy V. Khakimov Tatyana S. Pivina Nina N. Makhova 《Journal of heterocyclic chemistry》2013,50(2):326-336
An interaction of 1,2‐dialkyldiaziridine and 1,2,3‐trialkyldiaziridine with methyl propiolate was studied both in organic solvent (MeCN, CH2Cl2, C6H6) and in ionic liquids. Earlier unknown linear structures, in which three molecules of methyl propiolate were suited to one diaziridine molecule (adducts 1 : 3), were obtained in MeCN. The diaziridine ring expansion products 1,2,3,4‐tetrahydropyrimidine derivatives (adducts 1 : 2) and, along with them in some cases, the same linear structures were obtained in ionic liquids. A mechanism of reactions found was offered. The regioselectivity of reactions was supposed to determine by the structure of substituents in initial diaziridines. This conclusion was supported by quantum chemical calculations. 相似文献
993.
Mass spectrometric studies of 1‐ethyl‐3‐methylimidazolium and 1‐propyl‐2,3‐dimethylimidazolium bis(trifluoromethyl)‐sulfonylimides 下载免费PDF全文
994.
V. I. Petrenko M. V. Avdeev L. A. Bulavin L. Almasy N. A. Grigoryeva V. L. Aksenov 《Crystallography Reports》2016,61(1):121-125
The structures of ferrofluids (FFs) based on nonpolar solvent decahydronaphthalene, stabilized by saturated monocarboxylic acids with hydrocarbon chains of different lengths, C16 (palmitic acid) and ?12 (lauric acid), with an excess of acid molecules, have been studied by small-angle neutron scattering. It is found that the addition of acid to an initially stable system with optimal composition leads to more significant structural changes (related to aggregation) than those observed previously for this class of FFs. A comparison of the influence of monocarboxylic acids on the stability of nonpolar FFs suggests that the enhancement of aggregation is much more pronounced in the case of palmitic acid excess. This fact confirms the conclusion of previous studies, according to which an increase in the hydrocarbon chain length in a saturated acid reduces the efficiency of the corresponding FF stabilization. 相似文献
995.
996.
Stepan A. Ukhanev Sergei V. Fedorov Yuriy Y. Rusakov Irina L. Rusakova Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2022,60(9):901-914
All possible spin–spin coupling constants, 19F–19F, 19F–13C, and 19F–1H, of pentafluorobenzene were calculated at five different levels of theory, HF, DFT, SOPPA (CCSD), CCSD, and the SOPPA (CCSD)-based composite scheme with taking into account solvent, vibrational, relativistic, and correlation corrections. Most corrections were next to negligible for the long-range couplings but quite essential for the one-bond carbon–fluorine coupling constants. Hartree–Fock calculations were found to be entirely unreliable, while DFT results were comparable in accuracy with the data obtained using the wave function-based methods. 相似文献
997.
Leonid Mochalov Aleksey Nezhdanov Mikhail Kudryashov Alexandr Logunov Askold Strikovskiy Mikhail Gushchin Giuseppe Chidichimo Giovanni De Filpo Aleksandr Mashin 《Plasma Chemistry and Plasma Processing》2017,37(5):1417-1429
First time the method of plasma-enhanced chemical vapor deposition was used for preparation of As–Te chalcogenide films of different chemical and phase composition. The samples were synthesized via direct interaction of arsenic and tellurium vapors into low-temperature non-equilibrium RF (40 MHz) plasma discharge at reduced pressure (0.1 Torr). The plasma parameters such as temperature and concentration of electrons were measured by moving double probe diagnostic system. The dependence of solid phase radial distribution on plasma characteristics was established. Besides, the phase and structural evolution of As–Te films based on equilibrium coexistence of two phases (AsTe and As2Te3) and implemented by changing of the ratio of the initial substances in gas phase has been studied and discussed. 相似文献
998.
999.
Indirect relativistic bridge and substituent effects from the ‘heavy’ environment on the one‐bond and two‐bond 13C1H spin–spin coupling constants 下载免费PDF全文
Irina L. Rusakova Yury Yu. Rusakov Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2016,54(1):39-45
Indirect relativistic bridge effect (IRBE) and indirect relativistic substituent effect (IRSE) induced by the ‘heavy’ environment of the IV‐th, V‐th and VI‐th main group elements on the one‐bond and geminal 13C? 1H spin–spin coupling constants are observed, and spin‐orbit parts of these two effects were interpreted in terms of the third‐order Rayleigh–Schrödinger perturbation theory. Both effects, IRBE and IRSE, rapidly increase with the total atomic charge of the substituents at the coupled carbon. The accumulation of IRSE for geminal coupling constants is not linear with respect to the number of substituents in contrast to the one‐bond couplings where IRSE is an essentially additive quantity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
1000.