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61.
Diego Venegas-Yazigi Patricio Hermosilla-Ibáñez Juan Costamagna Evgenia Spodine Andrés Vega Verónica Paredes-García Eric Le Fur 《Macromolecular Symposia》2011,304(1):80-86
Summary: A novel coordination polymer[{Cu(en)2}(V10O28)]n · 2n[Cu(en)2(H2O)] · 2n(H3BO3) · 2n(H2O) was obtained by hydrothermal reaction. The compound crystallizes in the monoclinic crystal system, in the C2/c space group, with a = 26.490 (3) Å; b = 11.6558 (11) Å; c = 19.8426 (19) Å; β = 124.011 (1)°; V = 5078.6(8) Å3. The solid structure is formed by polymeric chains, [Cu(en)2(H2O)]2+ cations, and boric acid and water solvate molecules, stabilized through a multiple hydrogen bond network. 相似文献
62.
Carmen Paz Suárez Araujo Patricio García Báez Álvaro Sánchez Rodríguez José Juan Santana Rodríguez 《Analytical and bioanalytical chemistry》2009,394(4):1059-1072
In this paper, we approach, using neural computation and ensemble systems, a pattern classification problem in fluorescence
spectrometry, the resolution of difficult multi-fungicide mixtures (overlapping), specifically the benzimidazole fungicides,
benomyl, carbendazim, thiabendazole and fuberidazole. These fungicides are compounds of an important environmental interest.
Because of this, from an analytical point of view, it is interesting to develop sensitive, selective and simple methods for
their determination. Fluorescence spectrometry has proven to be a sensitive and selective technique for determination of many
compounds of environmental interest, but in some cases it is not enough. HUMANN is a hierarchical, unsupervised, modular,
adaptive neural net with high biological plausibility, which has shown to be suitable for identification of these fungicides
and organochlorinated compounds of environmental interest. We propose two modular artificial intelligent systems, with a structure
of pre-processing and processing stage, a multi-input HUMANN-based system, using multi-fluorescence spectra as input to the
system, and a HUMANN-ensemble system. We analyze the optimal configuration of inputs and the ensemble in order to obtain better
results. We study such figures as precision and sensitivity of the method. Our proposal is a smart, flexible and effective
complementary method, which allows reducing the analytical and/or computational complexity of the analysis.
Figure Stages in identification of benzimidazole fungicides
Based on a contribution presented at the XIII International Symposium on Luminescence Spectrometry held in Bologna, Italy
from Sept. 7–11, 2008. 相似文献
63.
Manuel Abad Cecilia Rossana Cimadamore José Patricio Díaz Varela 《Central European Journal of Mathematics》2009,7(2):299-309
In this paper, every monadic implication algebra is represented as a union of a unique family of monadic filters of a suitable
monadic Boolean algebra. Inspired by this representation, we introduce the notion of a monadic implication space, we give
a topological representation for monadic implication algebras and we prove a dual equivalence between the category of monadic
implication algebras and the category of monadic implication spaces.
相似文献
64.
Dynamic and static ultrasonic procedures involving ultrasonic bath and tandem focused ultrasound (i.e. two probes were used in the same sample treatment) have been assessed in order to implement a reliable solid-liquid back extraction of mercury from commercial resins (dowex and chelex-100), previously used to concentrate Hg(II) from treated urine. The urine had been previously treated with an advanced oxidation process provided by the conjunction of potassium permanganate, hydrochloric acid and high intensity focused ultrasound, which allowed that organic matter degradation was achieved in less than 3 min. 95 ± 10% of mercury in the certified urine and 97 ± 6% of the spiked methyl-mercury was recovered with the dowex resin plus the static ultrasonic procedure, whilst 96 ± 11% of the spiked mercury was recovered with the dowex resin plus the dynamic procedure, for which ultrasonication was not necessary. The Hg pre-concentration factor used in this work was 8 (20 mL of urine to 2.5 mL of acid), but different volume ratios can be used in order to increase this factor. 相似文献
65.
66.
Zapata-Torres G Fierro A Miranda-Rojas S Guajardo C Saez-Briones P Salgado JC Celis-Barros C 《Journal of chemical information and modeling》2012,52(5):1213-1221
Although substrate conversion mediated by human monoaminooxidase (hMAO) has been associated with the deprotonated state of their amine moiety, data regarding the influence of protonation on substrate binding at the active site are scarce. Thus, in order to assess protonation influence, steered molecular dynamics (SMD) runs were carried out. These simulations revealed that the protonated form of the substrate serotonin (5-HT) exhibited stronger interactions at the protein surface compared to the neutral form. The latter displayed stronger interactions in the active site cavity. These observations support the possible role of the deprotonated form in substrate conversion. Multigrid docking studies carried out to rationalize the role of 5-HT protonation in other sites besides the active site indicated two energetically favored docking sites for the protonated form of 5-HT on the enzyme surface. These sites seem to be interconnected with the substrate/inhibitor cavity, as revealed by the tunnels observed by means of CAVER program. pK(a) calculations in the surface loci pointed to Glu32?, Asp32?, His???, and Asp132 as candidates for a possible in situ deprotonation step. Docking analysis of a group of inhibitors (structurally related to substrates) showed further interactions with the same two docking access sites. Interestingly, the protonated/deprotonated amine moiety of almost all compounds attained different docking poses in the active site, none of them oriented to the flavin moiety, thus producing a more variable and less productive orientations to act as substrates. Our results highlight the role of deprotonation in facilitating substrate conversion and also might reflect the necessity of inhibitor molecules to adopt specific orientations to achieve enzyme inhibition. 相似文献
67.
In this paper we present a one dimensional and radial theory for the existence of eigenvalues and eigenfunctions for fully nonlinear elliptic (α+1)-homogeneous operators, α>−1. A general theory for the first eigenvalue and eigenfunction exists in the frame of viscosity solutions, but in this particular case a simpler theory can be established, that extends, via degree theory, to obtain the complete set of eigenvalues and eigenfunctions characterized by the number of zeros. 相似文献
68.
69.
Pessoa-Mahana H Núñez CU Araya-Maturana R Barría CS Zapata-Torres G Pessoa-Mahana CD Iturriaga-Vasquez P Mella-Raipán J Reyes-Parada M Celis-Barros C 《Chemical & pharmaceutical bulletin》2012,60(5):632-638
A series of 3-[3-(4-aryl-1-piperazinyl)-propyl]-1H-indole derivatives (12a-h) was synthesized and evaluated for binding affinity at the human 5-hydroxytryptamine(1A) receptor (5-HT(1A)R) compounds (12b) and (12h) showed the highest 5-HT(1A) receptor affinity (IC(50)=15 nM). Molecular docking studies with all the compounds in a homology model of 5-HT(1A) showed that the main interaction anchoring the ligand in the receptor was a charge-reinforced bond between the protonated nitrogen atom (N-4) of the piperazine ring and Aspartate(3.32). 相似文献
70.
Matías Bejide Patricio Contreras Pia Homm Boris Duran Jos Antonio García-Merino Andreas Rosenkranz Juliano C. Denardin Rodrigo del Río Samuel A. Hevia 《Molecules (Basel, Switzerland)》2020,25(22)
Nickel nanopillar arrays were electrodeposited onto silicon substrates using porous alumina membranes as a template. The characterization of the samples was done by scanning electron microscopy, X-ray diffraction, and alternating force gradient magnetometry. Ni nanostructures were directly grown on Si by galvanostatic and potentiostatic electrodeposition techniques in three remarkable charge transfer configurations. Differences in the growth mechanisms of the nanopillars were observed, depending on the deposition method. A high correlation between the height of the nanopillars and the charge synthesis was observed irrespective of the electrochemical technique. The magnetization measurements demonstrated a main dependence with the height of the nanopillars. The synthesis of Ni nanosystems with a controllable aspect ratio provides an effective way to produce well-ordered networks for wide scientific applications. 相似文献