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1.
Yi Liu David D. Díaz Adrian A. Accurso K. Barry Sharpless Valery V. Fokin M. G. Finn 《Journal of polymer science. Part A, Polymer chemistry》2007,45(22):5182-5189
1,2,3‐Triazole‐based polymers generated from the Cu(I)‐catalyzed cycloaddition between multivalent azides and acetylenes are effective adhesive materials for metal surfaces. The adhesive capacities of candidate mixtures of azide and alkyne components were measured by a modified peel test, using a customized adhesive tester. A particularly effective tetravalent alkyne and trivalent azide combination was identified, giving exceptional strength that matches or exceeds the best commercial formulations. The addition of Cu catalyst was found to be important for the synthesis of stronger adhesive polymers when cured at room temperature. Heating also accelerated curing rates, but the maximum adhesive strengths achieved at both room temperature and high temperature were the same, suggesting that crosslinking reaches the same advanced point in all cases. Polytriazoles also form adhesives to aluminum, but copper is bound more effectively, presumably because active Cu(I) ions may be leached from the surface to promote crosslinking and adhesion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5182–5189, 2007 相似文献
2.
V. S. Yuminov S. V. Kartsov V. L. Maksimov M. D. Bargamova A. V. Fokin 《Russian Chemical Bulletin》1989,38(4):845-849
Conclusions Perfluoro-2,4-dimethyl-2-fluorocarbonyl-1,3-dioxolane reacts with sodium carbonate to give perfluoro-2-methylene-2-methyl-1,3-dioxolane. Under the reaction conditions, the latter dimerizes to perfluoro-2-(2,4-dimethyl-1,3-dioxolan-2-ylmethylene)-4-methyl-1,3-dioxolane, and on treatment with CsF is converted into perfluoromethyl-(1,3-dioxolany-2-yl)ketone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 938–942, April, 1989. 相似文献
3.
A. V. Fokin Yu. A. Borisov A. F. Kolomiets N. I. Raevskii V. G. Enchev E. B. Bogachuk 《Russian Chemical Bulletin》1992,41(2):266-271
The heats of formation of polychloroarynes (PCA's) from polychlorobenzenes (PCB's) have been calculated by the AMI method as a function of the composition and structure of the PCB's according to a two-step scheme including deprotonation with the formation of carbanions (PCCA's, H1) and dechlorination to PCA's (H2). The influence of the solvent on H1 and H2 has been evaluated in the framework of the solvaton model. It has been shown that the value of H1 decreases as the number of C1 atoms in the PCB is increased, while H2 increases along the same series due to the increase in the relative stability of the PCCA as the number of C1 atoms is increased. Although the dimerization of PCA's with the formation of polychlorobiphenylenes (PCBP's) is forbidden by orbital symmetry rules, calculations of fragments of the potential-energy surface have shown that this reaction takes place with an energy barrier amounting to about 1 kcal/mole.A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Institute of Organic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 350–355, February, 1992. 相似文献
4.
Fokin AA Kushko AO Kirij AV Yurchenko AG Schleyer PR 《The Journal of organic chemistry》2000,65(10):2984-2995
The reaction of a series of ketones with dimsylsodium in dimethyl sulfoxide resulting in the formation of gamma-unsaturated thiols was studied experimentally. [2,3]-Sigmatropic rearrangements of beta-unsaturated sulfinyl carbanions are involved at the key step of those transformations. DFT computations at the B3LYP/6-31+G level indicated that such rearrangements, as well as some typical [2, 3]-sigmatropic rearrangements, e.g., thermal rearrangements of allyl sulfoxides and Wittig rearrangements of sulfur ylides and lithiated allyloxy methyl anions, are concerted and moderately synchronous processes. Negative (diatropic) nucleus-independent chemical shifts (NICS) and high diamagnetic susceptibility exaltations indicate that the transition structures of these [2,3]-sigmatropic migrations are aromatic. 相似文献
5.
R.?V.?Vedrinski? V.?L.?Kra?zman M.?P.?Lemeshko E.?S.?Nazarenko A.?A.?Novakovich L.?A.?Reznichenko V.?N.?Fokin V.?A.?Shuvaeva 《Physics of the Solid State》2009,51(7):1394-1398
The local atomic structure of PbTiO3, BaTiO3, and KNbO3 perovskite-type crystals and K x Na1 ? x NbO3 solid solutions in different phases is investigated using the angular dependence of the pre-edge structure of the Ti and Nb K X-ray absorption spectra and the EXAFS data. In noncubic phases, a considerable deviation of the local structure from the structure determined from diffraction data is observed only for the tetragonal phase of the BaTiO3 crystal. It is revealed that, in the cubic phase of niobates, the niobium atoms are characterized by significant displacements from the centrosymmetric positions along the threefold axes, so that they are close in the magnitude and the direction to the displacements in the low-temperatures rhombohedral phases. 相似文献
6.
7.
A. L. Pirozerskii E. V. Charnaya M. K. Lee L. J. Chang A. I. Nedbai Yu. A. Kumzerov A. V. Fokin M. I. Samoilovich E. L. Lebedeva A. S. Bugaev 《Acoustical Physics》2016,62(3):306-312
The paper presents the results of studying the crystallization and melting processes of Ga–In eutectic alloys, which are embedded in opal matrices, using acoustic and NMR methods. The indium concentrations in the alloys were 4, 6, 9, and 15 at %. Measurements were performed upon cooling from room temperature to complete crystallization of the alloys and subsequent heating. It is revealed how the size effects and alloy composition influence the formation of phases with α- and β-Ga structures and on changes in the melting-temperature ranges. A difference was observed between the results obtained using acoustic and NMR methods, which was attributed to different temperature measurement conditions. 相似文献
8.
9.
Yurii A. Serguchev Maxim V. Ponomarenko Lyudmila F. Lourie Andrey A. Fokin 《Journal of Physical Organic Chemistry》2011,24(5):407-413
The addition of 1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo[2.2.2]octane bis‐tetrafluoroborate (F‐TEDA) to unsaturated systems was modelled computationally at the ab initio levels and studied experimentally. The reaction of olefins with F‐TEDA is driven exclusively by charge transfer and displays the antibonding orbital picture in the transition structure for F‐transfer, similarly to that for the reactions of olefins with F‐radical. In contrast, the electrophilic and concerted fluorinations, respectively with H2O???F+ complex and with F2, show strong bonding interactions between the fluorine and olefin moieties in the transition structures. The reaction with F‐TEDA involves an initial formation of highly delocalized charge‐transfer complexes in the first step with further low‐barrier (ca 4 kcal) migration of fluorine and is best described as an inner‐sphere electron transfer. This nonelectrophilic mechanism is operative for the transannular addition of F‐TEDA to 3‐methylene‐7‐ethylidenebicyclo[3.3.1]nonane studied experimentally. The addition mode is determined by the formation of a more stable complex via the ethylidene fragment and demonstrates selectivities that differ from conventional electrophilic additions. This mechanistic scenario may be extended to the fluorination with xenon difluoride where similar products are formed in high yields. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
Fokin V. N. Son V. B. Fokina E. E. Tarasov B. P. 《Russian Journal of Applied Chemistry》2020,93(12):1831-1836
Russian Journal of Applied Chemistry - The reactions of intermetallic compounds ACo3 (A = Ce, Y) with hydrogen and ammonia at 20–450°C were studied. The composition of the products and... 相似文献