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921.
Francesco Aquilante Luca De Vico Nicolas Ferr Giovanni Ghigo Per‐ke Malmqvist Pavel Neogrdy Thomas Bondo Pedersen Michal Pitok Markus Reiher Bjrn O. Roos Luis Serrano‐Andrs Miroslav Urban Valera Veryazov Roland Lindh 《Journal of computational chemistry》2010,31(1):224-247
Some of the new unique features of the MOLCAS quantum chemistry package version 7 are presented in this report. In particular, the Cholesky decomposition method applied to some quantum chemical methods is described. This approach is used both in the context of a straight forward approximation of the two‐electron integrals and in the generation of so‐called auxiliary basis sets. The article describes how the method is implemented for most known wave functions models: self‐consistent field, density functional theory, 2nd order perturbation theory, complete‐active space self‐consistent field multiconfigurational reference 2nd order perturbation theory, and coupled‐cluster methods. The report further elaborates on the implementation of a restricted‐active space self‐consistent field reference function in conjunction with 2nd order perturbation theory. The average atomic natural orbital basis for relativistic calculations, covering the whole periodic table, are described and associated unique properties are demonstrated. Furthermore, the use of the arbitrary order Douglas‐Kroll‐Hess transformation for one‐component relativistic calculations and its implementation are discussed. This section especially focuses on the implementation of the so‐called picture‐change‐free atomic orbital property integrals. Moreover, the ElectroStatic Potential Fitted scheme, a version of a quantum mechanics/molecular mechanics hybrid method implemented in MOLCAS, is described and discussed. Finally, the report discusses the use of the MOLCAS package for advanced studies of photo chemical phenomena and the usefulness of the algorithms for constrained geometry optimization in MOLCAS in association with such studies. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献
922.
Marine Cuisinier Jean-Frédéric Martin Nicolas Dupré Atsuo Yamada Ryoji Kanno Dominique Guyomard 《Electrochemistry communications》2010,12(2):238-241
The impact of air exposure on LiFePO4–C nanocomposites has been investigated at moderate temperature. We show here that the storage in 120 °C hot air for 30 days leads not only to the material delithiation but also to the formation of an amorphous ferric phosphate side-phase, accounting for 38% of the total iron. The formed phase is found to be partially hydrated, suggesting a water-driven aging mechanism and a proposed hypothetic formula: LixFePO4(OH)x. The side-phase displays new electrochemical activity but poor cyclability and the overall battery performance is thus deteriorated. The regeneration of pristine structure, together with the performance recovery can be achieved by a simple thermal treatment under inert atmosphere. 相似文献
923.
924.
Carole Rais-Beghdadi Mario A. Roggero Nicolas Fasel Christophe D. Reymond 《Applied biochemistry and biotechnology》1998,74(2):95-103
The efficient removal of a N-or C-terminal purification tag from a fusion protein is necessary to obtain a protein in a pure
and active form, ready for use in human or animal medicine. Current techniques based on enzymatic cleavage are expensive and
result in the presence of additional amino acids at either end of the proteins, as well as contaminating proteases in the
preparation. Here we evaluate an alternative method to the one-step affinity/protease purification process for large-scale
purification. It is based upon the cyanogen bromide (CNBr) cleavage at a single methionine placed in between a histidine tag
and aPlasmodium falciparum antigen. The C-terminal segment of the circumsporozoite polypeptide was expressed as a fusion protein with a histidine tag
inEscherichia coli purified by Ni-NAT agarose column chromatography and subsequently cleaved by CNBr to obtain a polypeptide without any extraneous
amino acids derived from the cleavage site or from the affinity purification tag. Thus, a recombinant protein is produced
without the need for further purification, demonstrating that CNBr cleavage is a precise, efficient, and low-cost alternative
to enzymatic digestion, and can be applied to large-scale preparations of recombinant proteins. 相似文献
925.
N Primas P Verhaeghe A Cohen C Kieffer A Dumètre S Hutter S Rault P Rathelot N Azas P Vanelle 《Molecules (Basel, Switzerland)》2012,17(7):8105-8117
We report herein a simple and efficient two-step synthetic approach to new 2-trichloromethylquinazolines possessing a variously substituted sulfonamide group at position 4 used to prepare new quinazolines with antiparasitic properties. Thus, an original series of 20 derivatives was synthesized, which proved to be less-toxic than previously synthesized hits on the human HepG2 cell line, but did not display significant antiplasmodial activity. A brief Structure-Activity Relationship (SAR) evaluation shows that a more restricted conformational freedom is probably necessary for providing antiplasmodial activity. 相似文献
926.
Masurier N Aruta R Gaumet V Denoyelle S Moreau E Lisowski V Martinez J Maillard LT 《The Journal of organic chemistry》2012,77(7):3679-3685
A series of 20 optically pure 3,4-dihydro-5H-pyrido[1',2':1,2]imidazo[4,5-d][1,3]diazepin-5-ones which form a new family of azaheterocycle-fused [1,3]diazepines were synthesized in four steps with 17-66% overall yields. The key step consists of a selective C-acylation reaction of easily accessible 2-aminoimidazo[1,2-a]pyridine at C-3. 相似文献
927.
Nuss H Claiser N Pillet S Lugan N Despagnet-Ayoub E Etienne M Lecomte C 《Dalton transactions (Cambridge, England : 2003)》2012,41(22):6598-6601
A comparison of the topology of the experimental electron density, as revealed by high resolution X-ray diffraction, is provided for two prototypal transition metal alkyne complexes where the alkyne formally behaves as a 2 or 4e(-) donor. A higher value of the electron density ρ(r)(bcp) at the M(T)···C bond critical point (bcp), a lower value of ρ(r)(bcp) at the coordinated C≡C bcp, outwardly bent MC bond paths and a close to zero ellipticity for the C[triple bond, length as m-dash]C bond constitute the topological signature of a 4e(-) donor alkyne ligand. 相似文献
928.
Wesenhagen P Areephong J Fernandez Landaluce T Heureux N Katsonis N Hjelm J Rudolf P Browne WR Feringa BL 《Langmuir : the ACS journal of surfaces and colloids》2008,24(12):6334-6342
A bifunctional substituted dithienylcyclopentene photochromic switch bearing electropolymerisable methoxystyryl units, which enable immobilization of the photochromic unit on conducting substrates, is reported. The spectroscopic, electrochemical, and photochemical properties of a monomer in solution are compared with those of the polymer formed through oxidative electropolymerization. The electroactive polymer films prepared on gold, platinum, glassy carbon, and indium titanium oxide (ITO) electrodes were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The thickness of the films formed is found to be limited to several monolayer equivalents. The photochromic properties and stability of the polymer films have been investigated by UV/vis spectroscopy, electrochemistry, and XPS. Although the films are electrochemically and photochemically stable, their mechanical stability with respect to adhesion to the electrode was found to be sensitive to both the solvent and the electrode material employed, with more apolar solvents, glassy carbon, and ITO electrodes providing good adhesion of the polymer film. The polymer film is formed consistently as a thin film and can be switched both optically and electrochemically between the open and closed state of the photochromic dithienylethene moiety. 相似文献
929.
Nicolas Sary Laurent Rubatat Cyril Brochon Georges Hadziioannou Raffaele Mezzenga 《Macromolecular Symposia》2008,268(1):28-32
Summary: Two different approaches to obtain electron donor-acceptor interfaces via self-assembly of block copolymer systems are discussed, where the donor domains are formed by a π-conjugated rod-like polymer and the acceptor domains result from a coiled polymer modified by C60 fullerenes. In the first strategy, C60 is chemically grafted onto the coil polymer, typically a statistical copolymer of styrene and chloromethyl styrene. This has as major effect the increase in molecular weight and volume fraction of the coil block, which can markedly perturb the self-assembled block copolymer final morphologies and eventually suppress any microseparated nanostructure in favour of fully isotropic homogeneous phases. We discuss how the presence of free homopolymer rods in the system can help recovering a microphase separated morphology suitable for photovoltaic applications. In the second approach we discuss the poly(diethylhexyl-p-phenylenevinylene-b-4-vinylpyridine) (PPV-P4VP) rod-coil block copolymer system and we argue how supramolecular interactions among P4VP and free C60 can be exploited to blend rod-coil block copolymers and C60 preserving the original lamellar phase. 相似文献
930.