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221.
Emine Tekin Elisabeth Holder Veronica Marin Berend‐Jan de Gans Ulrich S. Schubert 《Macromolecular rapid communications》2005,26(4):293-297
Summary: Defined films of luminescent ruthenium(II ) polypyridyl‐poly(methyl methacrylate) (PMMA) and iridium(III ) polypyridyl‐polystyrene (PS) copolymers could be prepared by ink‐jet printing. The copolymers were deposited on photoresist‐patterned glass substrates. Films as thin as 120 nm could be printed with a roughness of 1 to 2%. In addition, the film thickness could be varied in a controlled way through the number of droplets deposited per unit area. The topography of the ink‐jet printed films was analyzed utilizing an optical profilometer. The absorbance and emission spectra were measured using fast parallel UV‐vis and fluorescence plate reader.
222.
A. Carel N. Kwamen Marcel Schlottmann Dr. David Van Craen Dr. Elisabeth Isaak Julia Baums Li Shen Ali Massomi Dr. Christoph Räuber Benjamin P. Joseph Prof. Dr. Gerhard Raabe Dr. Christian Göb Prof. Dr. Iris M. Oppel Dr. Rakesh Puttreddy Dr. Jas S. Ward Prof. Dr. Kari Rissanen Dr. Roland Fröhlich Prof. Dr. Markus Albrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(6):1396-1405
The dissociation of hierarchically formed dimeric triple lithium bridged triscatecholate titanium(IV) helicates with hydrocarbyl esters as side groups is systematically investigated in DMSO. Primary alkyl, alkenyl, alkynyl as well as benzyl esters are studied in order to minimize steric effects close to the helicate core. The 1H NMR dimerization constants for the monomer–dimer equilibrium show some solvent dependent influence of the side chains on the dimer stability. In the dimer, the ability of the hydrocarbyl ester groups to aggregate minimizes their contacts with the solvent molecules. Due to this, most solvophobic alkyl groups show the highest dimerization tendency followed by alkenyls, alkynyls and finally benzyls. Furthermore, trends within the different groups of compounds can be observed. For example, the dimer is destabilized by internal double or triple bonds due to π–π repulsion. A strong indication for solvent supported London dispersion interaction between the ester side groups is found by observation of an even/odd alternation of dimerization constants within the series of n-alkyls, n-Ω-alkenyls or n-Ω-alkynyls. This corresponds to the interaction of the parent hydrocarbons, as documented by an even/odd melting point alternation. 相似文献
223.
Dr. Daniela Mélanie Delannoy López Dr. Dong Tien Tran Dr. Guillaume Viault Dr. Sofiane Dairi Dr. Philippe Alexandre Peixoto Yoan Capello Laëtitia Minder Prof. Laurent Pouységu Dr. Elisabeth Génot Dr. Carmelo Di Primo Dr. Denis Deffieux Prof. Stéphane Quideau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(17):5498-5508
A selection of bioactive polyphenols of different structural classes, such as the ellagitannins vescalagin and vescalin, the flavanoids catechin, epicatechin, epigallocatechin gallate (EGCG), and procyanidin B2, and the stilbenoids resveratrol and piceatannol, were chemically modified to bear a biotin unit for enabling their immobilization on streptavidin-coated sensor chips. These sensor chips were used to evaluate in real time by surface plasmon resonance (SPR) the interactions of three different surface-bound polyphenolic ligands per sensor chip with various protein analytes, including human DNA topoisomerase IIα, flavonoid leucoanthocyanidin dioxygenase, B-cell lymphoma 2 apoptosis regulator protein, and bovine serum albumin. The types and levels of SPR responses unveiled major differences in the association, or lack thereof, and dissociation between a given protein analyte and different polyphenolic ligands. Thus, this multi-analysis SPR technique is a valuable methodology to rapidly screen and qualitatively compare various polyphenol–protein interactions. 相似文献
224.
Qian Wu Avijit Roy Elisabeth Irran Zheng‐Wang Qu Stefan Grimme Hendrik F. T. Klare Martin Oestreich 《Angewandte Chemie (International ed. in English)》2019,58(48):17307-17311
A metal‐free, intermolecular syn‐addition of hexamethyldisilane across simple alkenes is reported. The catalytic cycle is initiated and propagated by the transfer of a methyl group from the disilane to a silylium‐ion‐like intermediate, corresponding to the (re)generation of the silylium‐ion catalyst. The key feature of the reaction sequence is the cleavage of the Si?Si bond in a 1,3‐silyl shift from silicon to carbon. A central intermediate of the catalysis was structurally characterized by X‐ray diffraction, and the computed reaction mechanism is fully consistent with the experimental findings. 相似文献
225.
Anton Beyer Peter Wolschann Armin Becker Elisabeth Pranka Gerhard Buchbauer 《Monatshefte für Chemie / Chemical Monthly》1988,119(6-7):711-715
The conformations of two relatively rigid molecules with sandalwood odor have been investigated by molecular mechanics and the semiempirical method AM1. A comparison between both geometries shows that a common structural element exists in the relative rearrangement of a carbinol function and a quarternary carbon atom. The distance of these two centers as well as the electron density agree well in both structures.
Rechnungen zur Konformation von Molekülen mit Sandelholzgeruch, 1. Mitt.: Die Suche nach dem Geruchsprinzip des Sandelholzöles
Zusammenfassung Die Konformationen zweier relativ starrer Moleküle mit Sandelholzgeruch wurden mit molekularmechanischer und mit einer semiempirischen Methode (AM1) bestimmt. Ein Vergleich der beiden molekularer Geometrien zeigt ein gemeinsames Strukturelement und zwar die relative Anordnung der Carbinolfunktion zu einem quartären Kohlenstoffatom. Sowohl deren Abstand als auch deren Elektronendichte stimmen in beiden Verbindungen überein.相似文献
226.
Elisabeth Bouscaren 《Israel Journal of Mathematics》1984,49(1-3):15-25
InA proof of Vaught’s Conjecture for ω-stable theories, S. Shelah, L. Harrington and M. Makkai show thatω-stable theories satisfy Vaught’s Conjecture. By using their results and pushing the analysis one step further, we show thatω-stable theories also satisfy Martin’s Conjecture. 相似文献
227.
228.
Elisabeth Bouwman J. Christine Ten Hove Willem L. Driessen Jan Reedijk 《Polyhedron》1988,7(24):2591-2595
Transition metal coordination compounds with the novel N2S2-donor ligand 1,6-bis(4(5)-imidazolyl)-2,5-dithiahexane (abbreviated bhdhx) with general formulae M(bhdhx)(NO3)2(M = Co, Ni, Cu) and M(bhdhx)(H2O)2(BF4)2 (M = Cu, Zn) have been isolated. In all compounds the ligand is tetradentate with both thioether sulphurs and imidazole nitrogens coordinating. In all compounds the metal ions are six-coordinated in a distorted octahedral geometry with either nitrates or water molecules as the fifth and sixth ligands. This is confirmed by the ligand field spectra, which agree with a distorted octahedral coordination. The distortion from octahedral, indicated by the ligand field spectrum of the cobalt nitrate compound is such that the S atoms of the ligands must be at a very large distance from the metal ion. A single crystal of Cu(bhdhx)(NO3)2 was used in a structure determination: orthorhombic space group Pbcn, a = 14.351(5), b = 8.554(3), c = 13.057(4) Å, Z = 4, and T = 293 K. The structure was solved by heavy atom techniques and refined by least-squares methods to a residual R value of 0.033 for 847 significant reflections. The copper ion is at a special position on a two-fold axis, which causes a two-fold symmetry in the ligand. The coordination geometry of the copper atom is distorted octahedral with the two nitrates and the two thioether sulphurs in a cis position, and the imidazole nitrogens trans. The copper to nitrogen distances are 1.933(4) Å, the copper to sulphur distances are 2.495(1) Å, and the copper to oxygen distances are 2.280(3) Å. 相似文献
229.
Gamil Alhakimi Elisabeth Klemm 《Journal of polymer science. Part A, Polymer chemistry》1995,33(5):767-770
The tetrafunctional products 3 and 6 were synthesized via Diels-Alder reaction of bis(2-pyrone) with bismaleimides in mol ratio 1:7. The chemical structure of these products was determined by 1H-NMR spectroscopy; the high degree of purity was confirmed by means of elemental analysis. The cyclization of the tetraimide 3 with 2 mol monopyrone 7 to the bicycle 8 was carried out. © 1995 John Wiley & Sons, Inc. 相似文献
230.
Elisabeth E. C. Monteiro Eloisa B. Mano 《Journal of polymer science. Part A, Polymer chemistry》1984,22(3):533-545
In a previous article we presented preliminary information on IR spectrometric evidence for the interaction between poly(vinyl chloride) and ketones by using films with residual solvent as samples for spectrometry. This article reports detailed information on PVC–MEK film systems as compared to model compounds. The results indicate that there are “specific” interactions which were observed by a frequency shift of the carbonyl absorption of the ketone and changes on intensities of the C? Cl vibrational modes of the polymer, which are similar to the effects observed for nonpolymeric systems. 相似文献