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101.
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103.
H. G. Nowicki C. A. Kieda V. Current T. H. Schaefers 《Journal of separation science》1981,4(4):178-179
The novel application of azulene as a visual monitor of column chromatography performance during fractionation of complex waste water extracts for measurement of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at part-per-trillion concentrations is described. TCDD elutes directly behind azulene, the blue visual aid, in the 6% ethyl ether/hexane fraction during Florisil column chromatography. 相似文献
104.
Weronika Buczyńska Jarosław Buczyński Kaie Kubjas Mateusz Michałek 《Central European Journal of Mathematics》2013,11(9):1577-1592
We study semigroups of labellings associated to a graph. These generalise the Jukes-Cantor model and phylogenetic toric varieties defined in [Buczynska W., Phylogenetic toric varieties on graphs, J. Algebraic Combin., 2012, 35(3), 421–460]. Our main theorem bounds the degree of the generators of the semigroup by g + 1 when the graph has first Betti number g. Also, we provide a series of examples where the bound is sharp. 相似文献
105.
Rebarz M Ghesquière J Boisdenghien A Defrancq E Moucheron C Kirsch-De Mesmaeker A 《Inorganic chemistry》2010,49(23):10867-10874
The photoreaction mechanism of [Ru(TAP)(2)(phen)](2+) and [Ru(TAP)(3)](2+) (TAP = 1,4,5,8-tetraazaphenanthrene) with tryptophan (Trp), N-acetyl-Trp, and Lys-Trp-Lys is examined. The existence of a photoelectron-transfer process from the amino acid unit is demonstrated by laser flash photolysis experiments. The back electron transfer (BET) from the reduced complex to the oxidized amino acid, occurring at the microsecond time scale, corresponds approximately to an equimolecular-bimolecular process; however, it is disturbed by another reaction, originating from the oxidized Trp. Moreover, in competition with the BET, the reduced and oxidized intermediates give rise to an adduct. The latter is clearly detected by gel electrophoresis experiments in denaturing conditions, with a system composed of an oligonucleotide derivatized at the 3' end by the Ru(II)TAP complex and hybridized with the complementary sequence functionalized at the 5' end by the tripeptide Lys-Trp-Lys. Thus, upon illumination, a cross-linking between the two strands is observed, which originates from the presence of a Trp residue. 相似文献
106.
Mateusz F. Serafin Kraig A. Wheeler 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):o620-o621
The title bimolecular compound, C4H5N3·C21H18O2, constructed from 2‐aminopyrimidine and 3,3,3‐triphenylpropanoic acid, forms a tetramolecular hydrogen‐bonded motif via O—H...N, N—H...O and N—H...N contacts. This aggregate organizes to give crystal‐packing motifs with hydrophilic and hydrophobic regions. 相似文献
107.
108.
Artur Budzowski Mateusz Pitak Katarzyna Stadnicka 《Monatshefte für Chemie / Chemical Monthly》2007,138(12):1257-1266
Summary. Tricyclic cyclopenta[b]pyrrolo[3,4-c]pyridine-3,5-dione and pyrrolo[3,4-d]quinoline-3,5-diones with stable hemiaminal function or bicyclic azaspiro[4.4]nonanes and azaspiro[4.5]decanes were obtained
in a domino reaction of cycloalkenecarbothioamides with maleimides. The proposed mechanism involves Michael addition, ring transformation, aqueous hydrolysis of the imine, and additional ring closure which is observed exclusively
for one diastereoisomer. 相似文献
109.
110.
Paweł Tecmer Katharina Boguslawski Mateusz Borkowski Piotr S. Żuchowski Dariusz Kędziera 《International journal of quantum chemistry》2019,119(18):e25983
We present a comprehensive theoretical study of the electronic structures of the Yb atom and the Yb2 molecule, respectively, focusing on their ground and lowest-lying electronically excited states. Our study includes various state-of-the-art quantum chemistry methods such as CCSD, CCSD(T), CASPT2 (including spin-orbit coupling), and EOM-CCSD as well as some recently developed pCCD-based approaches and their extensions to target excited states. Specifically, we scan the lowest-lying potential energy surfaces of the Yb2 dimer and provide a reliable benchmark set of spectroscopic parameters including optimal bond lengths, vibrational frequencies, potential energy depths, and adiabatic excitation energies. Our in-depth analysis unravels the complex nature of the electronic spectrum of Yb2, which is difficult to model accurately by any conventional quantum chemistry method. Finally, we scrutinize the bi-excited character of the first excited state and its evolution along the potential energy surface. 相似文献