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101.
Dr. Maria Korabik Zuzana Repická Ladislav Martiška Jan Moncol Jozef Švorec Zdeňka Padělková Tadeusz Lis Milan Mazúr Prof. Dr. Dušan Valigura 《无机化学与普通化学杂志》2011,637(2):224-231
Polymeric salicylatocopper(II) complexes of unusual composition [C u(X‐ sal)2( μ‐denia)(H2O)]n [denia = diethylnicotinamide, and X‐sal = 5‐methylsalicylate ( 1 ), 3‐methylsalicylate ( 2 ), 4‐methoxysalicylate ( 3 ), 3,5‐dichlorosalicylate ( 4 ) and 3,5‐dibromosalicylate ( 5 )] were synthesized and characterized. Magnetic measurements were performed in the temperature range 1.8–300 K. The structural unit of all complexes consists of a CuII atom, which is monodentately coordinated by the pair of X‐salicylate anions in trans positions. Water and the diethylnicotinamide ligand occupy the other two basal plane positions of the tetragonal pyramid. The axial positions are occupied by a diethylnicotinamide oxygen atom of neighboring structural units, thus forming a spiral polymeric structure parallel to b axis. Magnetic measurements showed that all complexes 1 – 5 exhibit a susceptibility maximum at about 6–8 K. The obtained data fit to Bleaney–Bowers equation gave singlet‐triplet energy gaps 2J = –8.60 cm–1 for 1 , 2J = –6.57 cm–1 for 2 , 2J = –8.57 cm–1 for 3 , 2J = –6.82 cm–1 for 4 , and 2J = –6.45 cm–1 for 5 . The supramolecular structure based on hydrogen bonds [described by supramolecular synthons R22(10) and R22(12)] is the pathway for antiferromagnetic interactions of the magnetically coupled pairs of copper atoms of neighboring chains within the 2D supramolecular layers. The results of the magnetic measurements suggest involvement of the COO groups in the magnetic interaction pathway for all five complexes. 相似文献
102.
Pawe? Niedzia?kowski Tadeusz Ossowski Rados?aw Majewski Zdzis?awa Nowakowska Grzegorz Schroeder 《Monatshefte für Chemie / Chemical Monthly》2011,89(3):1121-1129
Abstract
In this work, the synthesis of various thiol-functionalized anthraquinone compounds is presented. The studied compounds were characterized by mass spectrometry and the main fragmentation pathways are discussed. The compounds studied formed stable self-assembled monolayers (SAMs) in the gold surface. The parameters for the reduction processes in the gold surface of the studied new anthraquinones were determined by cyclic voltamperometry tests. 相似文献103.
Kovalenko OO Brusylovets OA Kinzhybalo V Lis T Brusilovets AI 《Dalton transactions (Cambridge, England : 2003)》2011,40(18):4814-4817
The low-coordinate phosphorus compounds (Me(3)Si)(2)N-P=NSiMe(3), (Me(3)Si)(2)N-P(=S)=N(t)Bu and (Me(3)Si)(2)N-P(=NSiMe(3))(2) react with ((i)PrO)(3)M≡M(O(i)Pr)(3) (M = Mo, W) to form four- and five-membered metallacycles with intact endocyclic or exocyclic M≡M triple bonds. The first four-membered planar metallacycles, containing an M≡M triple bond were obtained in reaction with (Me(3)Si)(2)N-P=NSiMe(3). 相似文献
104.
With almost 20 years having passed since John B. Phillips described the first comprehensive two-dimensional gas chromatography
(GC × GC) separation, much has occurred in this ever-expanding field of separation science. GC × GC is currently one of the
most effective techniques for the separation and analysis of complex mixtures, offering significantly greater peak capacities
than conventional chromatographic methods. The technique is generally based upon separations performed on two chromatographic
columns characterized by considerably different selectivities, joined together through a modulating interface. The modulator
periodically traps or samples the primary column effluent, usually refocuses it into a narrow chromatographic band and injects
the focused fraction into the secondary column. The modulator is often referred to as the ‘heart’ of the instrument, since
a GC × GC separation is impossible without its use. This article reviews major innovations in GC × GC modulator development
since its first use by Phillips in 1991. Emphasis has been placed on modulator design and function. 相似文献
105.
Tadeusz Antczak 《Journal of Computational and Applied Mathematics》2011,235(17):4991-5000
In this paper, a new approximation method is introduced to characterize a so-called vector strict global minimizer of order 2 for a class of nonlinear differentiable multiobjective programming problems with (F,ρ)-convex functions of order 2. In this method, an equivalent vector optimization problem is constructed by a modification of both the objectives and the constraint functions in the original multiobjective programming problem at the given feasible point. In order to prove the equivalence between the original multiobjective programming problem and its associated F-approximated vector optimization problem, the suitable (F,ρ)-convexity of order 2 assumption is imposed on the functions constituting the considered vector optimization problem. 相似文献
106.
Efficiency in HPLC can be enhanced by increasing the column length and/or decreasing the particle size. The use of high temperature in HPLC has emerged as a valuable tool to overcome the increase in column backpressure when using small packing particles, as it allows for reduction in mobile phase viscosity. In this study, high plate count was obtained by coupling sub-2 ??m columns at elevated temperature to reduce the viscosity of the mobile phase, thus reducing the column backpressure. At 80 °C, up to three columns of 15 cm × 4.6 mm I.D. packed with 1.8 ??m particles could be coupled generating ~84,000 theoretical plates for the last eluting compound. The number of theoretical plates was increased on average by a factor of ~3.6 when three columns were coupled at 80 °C compared with one column at 30 °C. The relationships between separation efficiency and column length were examined using Van Deemter plots constructed at 30 °C and 80 °C for different column lengths. The advantages of using coupled columns in combination with elevated temperature for the environmental analysis were illustrated using test mixtures comprised of eight sulfonamides separated on one column at 30 °C and three coupled columns at 80 °C by isocratic elution. Sample clean up was carried out by employing solid-phase extraction (SPE) using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection and quantification limits. Recoveries generally ranged from 71.7 to 99% (with the exception of sulfanilamide), with standard deviations not higher than 4.7%. The detection limits of the method ranged from 0.6?C2 ??g L?1, while limits of quantification were in the range 2?C6.7 ??g L?1 with UV detection. 相似文献
107.
Wojciech Jankowski Maria Gdaniec Tadeusz Pooski 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o492-o494
The crystal structure of the title compound, benzamide–2,3,4,5,6‐pentafluorobenzoic acid (2/1), 2C7H7NO·C7HF5O2, consists of centrosymmetric hexameric supermolecules composed of four amide and two carboxylic acid molecules connected via O—H⋯O and N—H⋯O hydrogen bonds. No phenyl–perfluorophenyl π–π stacking interactions are observed in this cocrystal. 相似文献
108.
Christian Albrecht Christoph Wagner Kurt Merzweiler Tadeusz Lis Dirk Steinborn 《应用有机金属化学》2005,19(11):1155-1163
The platina‐β‐diketone [Pt2{(COMe)2H}2(µ‐Cl)2] ( 1 ) was found to react with monodentate phosphines to yield acetyl(chloro)platinum(II) complexes trans‐[Pt(COMe)Cl(PR3)2] (PR3 = PPh3, 2a ; P(4‐FC6H4)3, 2b ; PMePh2, 2c ; PMe2Ph, 2d ; P(n‐Bu)3, 2e ; P(o‐tol)3, 2f ; P(m‐tol)3, 2g ; P(p‐tol)3, 2h ). In the reaction with P(o‐tol)3 the methyl(carbonyl)platinum(II) complex [Pt(Me)Cl(CO){P(o‐tol)3}] ( 3a ) was found to be an intermediate. On the other hand, treating 1 with P(C6F5)3 led to the formation of [Pt(Me)Cl(CO){P(C6F5)3}] ( 3b ), even in excess of the phosphine. Phosphine ligands with a lower donor capability in complexes 2 and the arsine ligand in trans‐[Pt(COMe)Cl(AsPh3)2] ( 2i ) proved to be subject to substitution by stronger donating phosphine ligands, thus forming complexes trans‐[Pt(COMe)Cl(L)L′] (L/L′ = AsPh3/PPh3, 4a ; PPh3/P(n‐Bu)3, 4b ) and cis‐[Pt(COMe)Cl(dppe)] ( 4c ). Furthermore, in boiling benzene, complexes 2a – 2c and 2i underwent decarbonylation yielding quantitatively methyl(chloro)platinum(II) complexes trans‐[Pt(Me)Cl(L)2] (L = PPh3, 5a ; P(4‐FC6H4)3, 5b ; PMePh2, 5c ; AsPh3, 5d ). The identities of all complexes were confirmed by 1H, 13C and 31P NMR spectroscopy. Single‐crystal X‐ray diffraction analyses of 2a ·2CHCl3, 2f and 5b showed that the platinum atom is square‐planar coordinated by two phosphine ligands (PPh3, 2a ; P(o‐tol)3, 2f ; P(4F‐C6H4)3, 5b ) in mutual trans position as well as by an acetyl ligand ( 2a, 2f ) and a methyl ligand ( 5b ), respectively, trans to a chloro ligand. Single‐crystal X‐ray diffraction analysis of 3b exhibited a square‐planar platinum complex with the two π‐acceptor ligands CO and P(C6F5)3 in mutual cis position (configuration index: SP‐4‐3). Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
109.
Tadeusz Rzezuchowski 《Set-Valued Analysis》1997,5(2):181-193
The solutions of differential inclusions staying at the boundary of attained sets are investigated using the contingent cones to attained sets. The possibility of recovering the starting point and the time which elapsed since the beginning is shown when some fragments of an attained set are known. 相似文献
110.
An implementation of the p‐version of the finite element method for solving two‐dimensional linear elliptic problems on a shared‐memory parallel computer
is analyzed. The idea is to partition the problem among the available processors and perform computations corresponding to
different elements in parallel. The parallelization is based on a domain decomposition technique using the Lagrange multipliers.
The numerical experiments carried out on the Sequent system indicate very high performance of the mixed finite element algorithm
in terms of attained speedups.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献