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121.
Giang Huong Nguyen Thomas S. Dexheimer Andrew S. Rosenthal Wai Kit Chu Dharmendra Kumar Singh Georgina Mosedale Csanád Z. Bachrati Lena Schultz Masaaki Sakurai Pavel Savitsky Mika Abu Peter J. McHugh Vilhelm A. Bohr Curtis C. Harris Ajit Jadhav Opher Gileadi David J. Maloney Anton Simeonov Ian D. Hickson 《Chemistry & biology》2013,20(1):55-62
122.
Jackelyn M. Kembro Ana Georgina Flesia Raquel M. Gleiser María A. Perillo Raul H. Marin 《Physica A》2013
Detrended Fluctuation Analysis (DFA) is a method that has been frequently used to determine the presence of long-range correlations in human and animal behaviors. However, according to previous authors using statistical model systems, in order to correctly use DFA different aspects should be taken into account such as: (1) the establishment by hypothesis testing of the absence of short term correlation, (2) an accurate estimation of a straight line in the log–log plot of the fluctuation function, (3) the elimination of artificial crossovers in the fluctuation function, and (4) the length of the time series. Taking into consideration these factors, herein we evaluated the presence of long-range correlation in the temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus ). In our study, modeling the data with the general autoregressive integrated moving average (ARFIMA) model, we rejected the hypothesis of short-range correlations (d=0) in all cases. We also observed that DFA was able to distinguish between the artificial crossover observed in the temporal pattern of locomotion of Japanese quail and the crossovers in the correlation behavior observed in mosquito larvae locomotion. Although the test duration can slightly influence the parameter estimation, no qualitative differences were observed between different test durations. 相似文献
123.
Dasarath Mal Rupam Sen Georgina M. Rosair Subratanath Koner 《Journal of chemical crystallography》2011,41(7):1018-1022
Abstract
The reaction of aqueous solution of copper(II) nitrate trihydrate with methanolic solution of the ligand HL and sodium dicyanamide in aqueous medium results in the formation of a dimeric dicyanamide complex of Cu(II), [Cu2(L)2(μ1,5-dca)2]·0.5 H2O (1) [where L = 1-(N-salicylideneamine)-2-(N-ethyl)-aminoethane]. The single crystal X-ray structure reveals that the asymmetric unit of complex 1 consists of two dinuclear units. The complex crystallizes in the monoclinic space group P21 with cell parameters, a = 9.8828(19) ?, b = 19.018(4) ?, c = 14.851(3) ?, (°) = 92.979(6) and Z = 4. χM T, stays in the 0.94–0.91 cm3 mol−1 K range between 300 and 2 K, which is slightly higher than the spin-only value (χM T = 0.75 cm3 mol−1 K) for two uncoupled copper(II) (S = ?) ions assuming g = 2.0, thus indicating that the complex 1 behaves like a simple paramagnet. 相似文献124.
Aitken G Hazari N Frey AS Cloke FG Summerscales O Green JC 《Dalton transactions (Cambridge, England : 2003)》2011,40(42):11080-11088
The role of U((η-C(8)H(6){Si(i)Pr(3)-1,4}(2))(η-C(5)Me(5)) and U((η-C(8)H(6){Si(i)Pr(3)-1,4}(2))(η-C(5)Me(4)H) in the reductive di- tri- and tetramerization of CO has been modelled using density functional methods and U(C(8)H(8))(C(5)H(5)) as the metal fragment. The orbital structure of U(C(8)H(8))(C(5)H(5)) is described. CO binding to form a monocarbonyl U(C(8)H(8))(C(5)H(5))(CO) is found, by a variety of methods, to place spin density on the CO ligand via back-bonding from the U5f orbitals. A possible pathway for formation of the yne diolate complex [U(C(8)H(8))(C(5)H(5))](2)C(2)O(2) is proposed which involves dimerization of U(C(8)H(8))(C(5)H(5))CO via coordination of the CO O atoms to the opposing U atoms followed by C-C bond formation to form a zig-zag intermediate, stable at low temperatures. The intermediate then unfolds to form the yne diolate. The structures of [U(C(8)H(8))(C(5)H(5))]C(2)O(2), the deltate complex [U(C(8)H(8))(C(5)H(5))]C(3)O(3) and the squarate complex [U(C(8)H(8))(C(5)H(5))]C(4)O(4) are optimized and provide good models for the experimental compounds. The reaction of further CO with a zig-zag intermediate to form deltate and squarate complexes was explored using Th(C(8)H(8))(C(5)H(5)) as a model and low energy pathways are proposed. 相似文献
125.
Tricas H Colon M Ellis D Macgregor SA McKay D Rosair GM Welch AJ Glukhov IV Rossi F Laschi F Zanello P 《Dalton transactions (Cambridge, England : 2003)》2011,40(16):4200-4211
The icosahedral carboranes 1-C(6)F(5)-2-Ph-1,2-closo-C(2)B(10)H(10) (1), 1-(4'-F(3)CC(6)H(4))-2-Ph-1,2-closo-C(2)B(10)H(10) (2), 1,2-(4'-F(3)CC(6)H(4))(2)-1,2-closo-C(2)B(10)H(10) (3), 1-(4'-H(3)CC(6)F(4))-2-Ph-1,2-closo-C(2)B(10)H(10) (4), 1-(4'-F(3)CC(6)F(4))-2-Ph-1,2-closo-C(2)B(10)H(10) (5), 1,2-(4'-F(3)CC(6)F(4))(2)-1,2-closo-C(2)B(10)H(10) (6), 1,7-(4'-F(3)CC(6)F(4))(2)-1,7-closo-C(2)B(10)H(10) (7) and 1,12-(4'-F(3)CC(6)F(4))(2)-1,12-closo-C(2)B(10)H(10) (8), with fluorinated aryl substituents on cage carbon atoms, have been prepared in good to high yields and characterised by microanalysis, (1)H, (11)B and (19)F NMR spectroscopies, mass spectrometry, single-crystal X-ray diffraction and (spectro)electrochemistry. By analysis of <δ(11)B>, the weighted average (11)B chemical shift, a ranking order for the ortho carboranes 1-6 is established based on the combined electron-withdrawing properties of the C-substituents, and is in perfect agreement with that established independently by electrochemical study. In a parallel computational study the effects of a wide range of different substituents on the redox properties of carboranes have been probed by comparison of ΔE values, where ΔE is the energy gap between the DFT-optimised [7,9-R(2)-7,9-nido-C(2)B(10)](2-) anion and its DFT-optimised basket-shaped first oxidation product. The overall conclusion from the NMR spectroscopic, electrochemical and computational studies is that strongly electron withdrawing substituents significantly stabilise [7,9-nido-C(2)B(10)](2-) dianions with respect to oxidation, and that the best practical substituent is 4-F(3)CC(6)F(4). Thus attention focussed on the reduction of 1,2-(4'-F(3)CC(6)F(4))(2)-1,2-closo-C(2)B(10)H(10), compound 6. The sequence 6/[6](-)/[6](2-) appears reversible on the cyclic voltammetric timescale but on the longer timescale of macroelectrolysis the radical anion is only partially stable. EPR study of the electrogenerated monoanions from the ortho-carboranes 1-6 confirms the cage-centred nature of the redox processes. In contrast, the reduction of the meta- and para-carboranes 7 and 8, respectively, appears to be centred on the aromatic substituents, a conclusion supported by the results of DFT calculation of the LUMOs of compounds 6-8. Bulk 2-electron reduction of 6 affords a dianion which is remarkably stable to reoxidation, surviving for several hours in the open laboratory in the absence of halogenated solvents. 相似文献
126.
M. Judith Percino Víctor M. Chapela Manuel Salmón Georgina Espinosa-Pérez Ana M. Herrera Américo Flores 《Journal of chemical crystallography》1997,27(9):549-552
We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that is shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion. 相似文献
127.
The asymmetric synthesis of the potent selective NOP agonist 2-(3-{1-[3-(5-methoxy-2-methyl-phenoxy)-4-methyl-pentyl]-piperidin-4-yl}-2-oxo-2,3-dihydro-benzimidazol-1-yl)-N-methyl-acetamide and analogues was developed. The key step, chiral reduction of methyl isobutyryl acetate, was achieved using a mild Noyori-type asymmetric hydrogenation. 相似文献
128.
Two new octahedral Cd(II) complexes [Cd(L)2] (1) and {[Cd(LH)2(SCN)2]H2O} (2) [where LH = C14H13N3O] are synthesized using a tridentate hydrazone ligand (LH) and they are characterized by elemental analysis, IR spectra, NMR spectra, thermal studies and finally the structures have
been determined by single crystal X-ray diffraction. Complex 1 crystallizes in monoclinic system, space group C2/c with a = 22.565(6) ?, b = 10.252(3) ?, c = 12.187(4) ?, β = 118.851(2)∘, and Z = 4. Complex 2 also crystallizes in the monoclinic system, space group P21/c with a = 9.257(9)?, b = 17.809(2)?, c = 9.548(9)?, β = 107.439(4)∘, and Z = 2. In 1 the ligand binds the Cd(II) ion in tridentate fashion, whereas in 2 it acts as a bidentate ligand. 相似文献
129.
de la Puente Luz M White CT Rivera-Sagredo A Reilly J Burton K Harvey G 《Journal of chromatography. A》2003,983(1-2):101-114
Novel normal-phase gradient systems have been employed for fast high-throughput chiral analyses of Discovery compounds in our research laboratories in Eli Lilly and Company. In this report, we describe an automated screening approach based on gradient elution, in order to achieve accurate enantiomeric excess determinations, and chiral separations when needed, in the shortest possible timeframe. Baseline resolution of enantiomers has been obtained for over 85% of the samples so tested. For the remaining cases, complete enantioseparation by isocratic optimisation is generally achieved in a single shot. This technique has been proven to be robust and is now standard operating procedure at our analytical research laboratories. 相似文献