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81.
Time harmonic Maxwell equations in lossless media lead to a second order differential equation for the electric field involving a differential operator that is neither elliptic nor definite. A Galerkin method using Nedelec spaces can be employed to get approximate solutions numerically. The problem of preconditioning the indefinite matrix arising from this method is discussed here. Specifically, two overlapping Schwarz methods will be shown to yield uniform preconditioners.
82.
B. Viswanathan R. Gopalakrishnan R. Vetrivel 《Reaction Kinetics and Catalysis Letters》1982,18(1-2):209-212
Three different binding states of CO on cobalt surfaces have been identified by TPD studies. The energetics of these adsorption states and their relevance in Fischer-Tropsch synthesis are considered.
CO - . -.相似文献
83.
AVO3 (A = Ba2+, Sr2+, La3+, Gd3+) oxides have been prepared by hydrogen reduction of suitable vanadium(V) ternary oxides. The oxidation state of vanadium in the reduction products seems to be controlled by the nature of other cations. In the presence of strongly basic alkaline-earth metal ions, Ba2+ and Sr2+ as in Ba2V2O7 and Sr2V2O7, vanadium is reduced to +4 state. But when A is a trivalent lanthanide ion as in LnVO4 (Ln = La or Gd), the reduction of vanadium proceeds to +3 state to yield LnVO3 phases. The products have been characterized by X-ray diffraction. BaVO3 crystallizes in a hexagonal structure related to Ba3V2O8 while SrVO3, LaVO3 and GdVO3 crystallize in GdFeO3 type structure. Electrical transport measurements indicate that BaVO3, LaVO3 and GdVO3 are p-type semiconductors while SrVO3 is metallic. 相似文献
84.
N. Vijayan G. Bhagavannarayana K. K. Maurya S. Pal S. N. Datta R. Gopalakrishnan P. Ramasamy 《Crystal Research and Technology》2007,42(2):195-200
Single crystal of 8‐hydroxyquinoline (8HQ) having chemical formula C9H7NO, an organic nonlinear optical (NLO) material has been successfully grown by slow evaporation solution growth technique at room temperature. The crystal system has been confirmed from the powder X‐ray diffraction (PXRD) analysis. The crystalline perfection was evaluated by high resolution X‐ray diffractometry (HRXRD). From this analysis we found that the quality of the crystal is quite good. However, a very low angle (tilt angle 14 arc sec) boundary was observed which might be due to entrapping of solvent molecules in the crystal during growth. Its optical behavior has been examined by UV‐Vis. analysis, which shows the absence of absorbance between the wavelengths ranging from 400 to 1200 nm. From the thermal analysis it was observed that the material exhibits single sharp weight loss starting at 113°C without any degradation. The laser damage threshold was measured at single shot mode and the SHG behavior has been tested using Nd:YAG laser as a source. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
85.
Dr. Priyankar Paira Mun Juinn Chow Gopalakrishnan Venkatesan Vamsi Krishna Kosaraju Dr. Siew Lee Cheong Karl‐Norbert Klotz Dr. Wee Han Ang Assoc.Prof. Giorgia Pastorin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8321-8330
Human A3 adenosine receptor (hA3AR) is a membrane‐bound G protein‐coupled receptor implicated in a number of severe pathological conditions, including cancer, in which it acts as a potential therapeutic target. To derive structure–activity relationships on pyrazolo–triazolo–pyrimidine (PTP)‐based A3AR antagonists, we developed a new class of organometallic inhibitors through replacement of the triazolo moiety with an organoruthenium fragment. The objective was to introduce by design structural diversity into the PTP scaffold in order to tune their binding efficacy toward the target receptor. These novel organoruthenium antagonists displayed good aquatic stability and moderate binding affinity toward the hA3 receptor in the low micromolar range. The assembly of these complexes through a template‐driven approach with selective ligand replacement at the metal center to control their steric and receptor‐binding properties is discussed. 相似文献
86.
Amuthan Arunkumar Ramabathiran S. Gopalakrishnan 《Journal of Computational and Applied Mathematics》2012
An energy–momentum conserving time integrator coupled with an automatic finite element algorithm is developed to study longitudinal wave propagation in hyperelastic layers. The Murnaghan strain energy function is used to model material nonlinearity and full geometric nonlinearity is considered. An automatic assembly algorithm using algorithmic differentiation is developed within a discrete Hamiltonian framework to directly formulate the finite element matrices without recourse to an explicit derivation of their algebraic form or the governing equations. The algorithm is illustrated with applications to longitudinal wave propagation in a thin hyperelastic layer modeled with a two-mode kinematic model. Solution obtained using a standard nonlinear finite element model with Newmark time stepping is provided for comparison. 相似文献
87.
Solvent effects in the reaction between (anthracen‐9‐yl)methyl sulfides and electron‐deficient acetylenes 下载免费PDF全文
Reshma Gopalakrishnan Jomon P. Jacob Rekha R. Mallia Perupparampil A. Unnikrishnan Sreedharan Prathapan 《Journal of Physical Organic Chemistry》2015,28(7):472-479
Solvent‐dependent diverse reactivity of (anthracen‐9‐yl)methyl sulfides with a few electron‐deficient acetylenes is described. Diversity in reactivity is attributed to competition between one electron transfer, two electron transfer and Diels–Alder reaction of these sulfides with electron‐deficient acetylenes. We have proposed plausible mechanisms to account for various reactions observed by us. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
88.
89.
Jomon P. Jacob Reshma Gopalakrishnan Rekha R. Mallia Jean John Vadakkan Perupparampil A. Unnikrishnan Sreedharan Prathapan 《Journal of Physical Organic Chemistry》2014,27(11):884-891
Herein, we describe diverse reactivity of (anthracen‐9‐yl)methanamines with a few electron‐deficient acetylenes. Depending on the solvent and concentration, (anthracen‐9‐yl)methanamines reacted with acetylenes through one electron transfer, two electron transfer, or Diels–Alder pathways; and under certain conditions, we observed multiple reaction pathways. We have proposed plausible mechanisms to account for various reactions observed by us. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
90.
V. Kanagarajan J. Thanusu M. R. Ezhilarasi M. Gopalakrishnan 《Chemistry of Heterocyclic Compounds》2011,47(1):60-66
A novel approach towards the synthesis of spiropiperidinyl 1,2,4-triazolidine-3-thiones was proposed, exploiting microwave
activation coupled with solvent-free reaction conditions. In search for new leads towards potent antimicrobial agents, we
tested all the synthesized compounds for their in vitro antibacterial activity against Bacillus subtilis and Micrococcus luteus
and antifungal activity against Aspergillus niger, Candida albicans, Candida-6, and Candida-51. Two of the compounds exerted
strong in vitro antibacterial activity against B. subtilis and M. luteus, and all the synthesized compounds were potent against
the tested fungal strains. 相似文献