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11.
12.
Tapan Kumar Sengupta 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):2065-2070
In the complete absence of a systematic polymer nomenclature, a scheme of nomenclature based on structure is proposed. The problem of naming a “mer” has been solved for an addition polymer by adding “ne” to the monomer name, the justification being on withdrawal of a π bond a monomer becomes a mer. To furnish completeness to the nomenclature, condensation polymers were included in the system. The present nomenclature system of polymers is very arbitrary. Some polymers are not chemically named, some named incorrectly, and there are some fantastic names. After pointing these out, the possible solutions were shown, encompassing a systematic discussion on nearly every type of polymer–linear, branched, or crosslinked–and copolymer (including block or graft), and plastic, fiber, or rubber, and stereospecific polymer. One or more names were proposed for different cases. 相似文献
13.
Sengupta Soumitra K. Pandey Om P. Srivastava Bimal K. Sharma Vinod K. 《Transition Metal Chemistry》1998,23(4):349-353
The reactions of bis(cyclopentadienyl)titanium(IV)/zirconium(IV) dichloride with a new class of organometallic thiosemicarbazones (LH), derived by condensing acetylferrocene with substituted thiosemicarbazides, have been studied and two types of bimetallic products, viz. [Cp2M(L)Cl] (M = Ti or Zr) and [CpZr(L)3], have been isolated. On the basis of various physicochemical and spectral studies, five- and seven-coordinate structures have been assigned to these derivatives, respectively. Attempts have been made to establish a correlation between biological activity and the structures of the products. 相似文献
14.
Preparation and properties of the salts of the series MVO2F4, where M = NH, Na+, K+, 1/2 Ni2+, and 1/3 [Co(NH3)6]3+ are described. Molecular conductivity of Na3VO2F4 at different dilutions indicates that Na3VO2F4 dissociates into 3 Na+ and VOaF ions. Ion exchange study of (NH4)3VO2F4 solution through cation exchange resin (H+ form) suggests that the corresponding acid decomposes partly to vanadium pentoxide. Reaction between (NH4)3VO2F4 with BaCl2 and AgNO3 solutions shows the formation of BaVO2F3 and AgVO3 respectively. Thermogravimetric study of (NH4)3VO2F4 shows the formation of impure vanadium pentoxide as the ultimate product on heating up to 450°C. X-ray powder diffraction data are given for (NH4)3VO2F4 and Na3VO2F4. 相似文献
15.
The kinetics of the interaction of DL-methionine with [Pt(en)(H2O)2]2+ have been studied spectrophotometrically as a function of [Pt(en)(H2O)22+], [DL-methionine], PH and temperature. The reaction proceeds via a rapid outer sphere association followed by two slow consecutive steps having first order dependence on the aqua ion and methionine concentrations. Activation parameters have been evaluated using the Eyring equation. The low H1 (15.6 kJ mol–1) and large negative value of S1 (–230 J K–1 mol–1) as well as H2 (19.5 kJ mol–1) and S2 (–226 J K–1 mol–1) indicate an associative mode of activation for both the aqua ligand substitution processes in the two consecutive steps. 相似文献
16.
Vinod K. Sharma Om P. Pandey Soumitra K. Sengupta Dost M. Halepoto 《Transition Metal Chemistry》1989,14(4):263-266
Summary The reactions of MCl3·3H2O (M=Ru, Rh or Ir) with hydrazones have been studied by three different methods and complexes of the types [M(LH2)(H2O)2]Cl3, [M(L)Cl(H2O)] and [M(LH2)Cl2]Cl·H2O have been isolated. Tentative structural conclusions are drawn for these products based upon elemental analysis, electrical conductance, magnetic moment, and i.r. and1H n.m.r. data. The thermal stability and mode of decomposition for the complexes have been studied by t.g.a., d.t.g. and d.s.c. techniques. 相似文献
17.
S. Roy S. Sengupta D. Mukherjee P. K. Mukherjee 《International journal of quantum chemistry》1986,29(2):205-210
We report in this paper the results of outer and inner valence IP calculations for the HF molecule using two different many-body methods for the direct evaluation of energy differences. The first is the nonperturbative coupled-cluster based linear response theory (LRT) and the second is the hermitian open-shell many-body perturbation theory (MBPT). A Huzinaga-Dunning (9s5p→ 5s3p/3s) basis has been used. LRT uses an “ionization operator” S as in the equation of motion method (EOM) to generate the ionized states from a coupled-cluster type of ground state. S is chosen to consist of single ionization and ionization-cum-shake-up operators, thus treating the Koopmans as well as the shake-up states on equal footing. LRT would thus be capable of computing both the outer and the inner valence regions with equal facility. This is borne out by the results. For the open-shell MBPT, the model space is chosen to be spanned by the singly ionized determinants. The convergence of the results for the inner valence region is slow, and the results obtained from the [2, 1] Pade' approximants are presented. Unlike the LRT, the inner valence region is not reproduced with full complexity in MBPT, indicating that it is essential to modify the theory by way of expanding the model space to contain the shake-up determinants also. 相似文献
18.
Summary Ruthenium(III) complexes of types [Ru(L)3], [Ru(L)Cl(H2O)2], [Ru(L)Cl2]n, [Ru(L)Cl(H2O)]n(LH =Schiff bases derived from anthranilic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH2=Schiff bases derived from anthranilic acid and salicylaldehyde oro-hydroxyacetophenone; LH=Schiff bases derived fromp-aminobenzoic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH2=Schiff bases derived fromp-aminobenzoic acid and salicylaldehyde oro-hydroxyacetophenone) have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic moment and spectral (electronic, i.r. and1H n.m.r.) data. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of crystal field theory and various parameters have been evaluated. On the basis of the electronic spectra, an octahedral geometry has been established for all these complexes except [Ru(L)Cl2]n. The complexes [Ru(L)Cl2]n are pentacoordinate and a trigonal-bipyramidal environment, D3h, is suggested for the ruthenium(III) ion. The thermal behaviour of these complexes has also been studied by t.g., d.t.g and d.s.c techniques. Heats of reaction for the decomposition steps were calculated from the d.s.c. curves. The antifungal and antiviral activities of the complexes with Schiff bases derived from anthranilic acid were also investigated. 相似文献
19.
Jnanadeva Maharana Samir K. Paul Gautam Sengupta 《Communications in Mathematical Physics》1991,139(3):527-549
The Neveu-Schwarz-Ramond type II closed superstring is considered to evolve in a curved space-time manifold. The Krichever-Novikov global operator formalism is used to construct the generators of a super-conformal algebra on a Riemann surface . The computation for the quantum algebra of these generators is explicitly presented. It is shown that the theory is free from super-conformal anomalies if the target manifold is ten dimensional and satisfies the Ricci flatness condition. 相似文献
20.
We clarify some aspects of our derivation of a Bell-type inequality, in response to a paper by Elby.The following comments refer to Andrew Elby's discussion note immediately following our present paper.(a) We wish to stress that physical distinction between NC and LC is particularly important in the case of local realist theories violating NC for any single system but satisfying LC for any correlated many-component system. Arguments given by Elby do not rule out a reasonable theory violating NC but obeying LC. Therefore, a physically meaningful possibility exists that while Bell's inequality derived from NC is violated for a single system, the inequality derived from LC is satisfied for correlated and spatially separated (non-interacting) systems. It is precisely this possibility which was explored by HS in deriving Bell's inequality from NC.(b) Since Elby's formulation of locality condition necessarily involves a relativistic constraint at the level of individual measurements, it is pointless to discuss its compatibility with predictions derived from non-relativistic quantum mechanics, which is well known to allow superluminal communication by mechanisms such as wavepacket travel or spread. Recently this aspect has been discussed in depth by P. Ghose and D. Home,Phys. Rev. A
43, 6382 (1991). It needs to be stressed that our formulation of LC is in line with the separability condition articulated by Einstein in different contexts; see, for example,J. Franklin Inst.
221, 349 (1936), reprinted inIdeas and Opinions (Crown, New York, 1954), pp. 290–323.On leave from: Department of Physics, Bose Institute, Calcutta 700009, India. 相似文献