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401.
It is shown that non-convergent calculations of the Fermi contact term of spin-spin coupling constants within the self-consistent and finite perturbation schemes used to solve the coupled Hartree-Fock equations, are originated in non-singlet Hartree-Fock instabilities of the closed-shell restricted Hartree-Fock wavefunction. In CNDO/S and INDO/S wavefunctions, where the electronic system response has been successfully reproduced, all investigated molecules containing MOs were found to be unstable. Results of spin-spin coupling constants are given and compared with experimental as well as FP and SOS INDO values.Part of a Ph.D. thesis (G.E.S.) to be presented to the University of Buenos Aires.Comisión de Investigaciones Científicas (CIC, Pcia. de Bs. As.) fellow. 相似文献
402.
Marisela Reyes Daniel Mercades Bernardo Fontal Trino Suárez Fernando Bellandi Ricardo R. Contreras Isolda Romero Yuraima Fonseca Pedro Cancines 《Reaction Kinetics and Catalysis Letters》2007,90(2):347-354
The chlorocarbonyl bis-[butylphenyl (meta-sulfonate-phenyl)phosphine] rhodium (I) complex shows catalytic hydroformylation
activity in toluene/water biphasic medium for 1-hexene, cyclohexene, 2,3-dimethyl-2-butene and 2-methyl-2-pentene, their binary
mixtures and a real Venezuelan naphtha, under standardized reaction conditions (1000 psi of syngas (1:1 H2/CO), 100°C, substrate/catalyst molar ratio (600:1) and 4 h reaction time), obtaining high percent conversion to oxygenated
products. 相似文献
403.
M. E. Vaschetto B. A. Retamal M. L. Contreras J. H. Zagal L. O. S. BulhÕes 《Structural chemistry》1995,6(2):131-140
We present some semiempirical quantum chemistry calculations, geometric structures, charge distribution, gap energy, and enthalpy of formation (H
f
) for aniline oligomers in the different oxidation states using the AM1 method. A linear relationship between calculated optical transition values and the experimental reported ones was found. The effect of the interaction between the chloride counterion and these molecules was analyzed and indicates a decrease both in H
f
of the aniline oligomers in the radical cation state and in E(SOMO-LUMO). The withdrawal of one electron from the reduced aniline tetramer to form a radical cation in the presence of chloride (Cl–) yields to the radical cation band, similar to the polaron band in the polyaniline case. Contrary to the expected results, our calculations show that Cl– was able to transfer about 80% of its charge to the oligomers. 相似文献
404.
Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bacchetta N Bailey MW Bamberger A de Barbaro P Barnett BA Barbaro-Galtieri A Barnes VE Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Bisello D Blair R Blocker C Bodek A Bolognesi V Booth AW Boswell C Brandenburg G Brown D Buckley-Geer E Budd HS Busetto G Byon-Wagner A Byrum KL Campagnari C Campbell M Caner A Carey R Carithers W Carlsmith D 《Physical review letters》1992,68(8):1104-1108
405.
Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bacchetta N Bailey MW Bamberger A de Barbaro P Barnett BA Barbaro-Galtieri A Barnes VE Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Bisello D Blair R Blocker C Bodek A Bolognesi V Booth AW Boswell C Brandenburg G Brown D Buckley-Geer E Budd HS Busetto G Byon-Wagner A Byrum KL Campagnari C Campbell M Caner A Carey R Carithers W Carlsmith D 《Physical review letters》1992,68(23):3403-3407
406.
Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bacchetta N Bailey MW Bamberger A de Barbaro P Barnett BA Barbaro-Galtieri A Barnes VE Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Blair R Blocker C Bloom K Bolognesi V Booth AW Boswell C Brandenburg G Brown D Buckley-Geer E Budd HS Busetto G Byon-Wagner A Byrum KL Campagnari C Campbell M Caner A Carey R Carithers W Carlsmith D Carroll JT 《Physical review letters》1992,68(23):3398-3402
407.
Abe F Albrow M Amidei D Anway-Wiese C Apollinari G Areti H Auchincloss P Azfar F Azzi P Bacchetta N Badgett W Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Beretvas A Bhatti A Biery K Binkley M Bird F Bisello D Blair RE Blocker C Bodek A Bolognesi V Boswell C Boulos T Brandenburg G Buckley-Geer E Budd HS Burkett K Busetto G Byon-Wagner A Byrum KL Campagnari C Campbell M 《Physical review letters》1993,71(11):1685-1689
408.
Filippo Bracci Manuel D. Contreras Santiago Díaz-Madrigal 《Advances in Mathematics》2007,208(1):318-350
We give a complete classification up to conjugation of continuous semigroups of linear fractional self-maps of the unit ball. 相似文献
409.
Abraham F. Jalbout Flavio F. Contreras‐Torres L. Adamowicz 《International journal of quantum chemistry》2008,108(2):279-288
In this work we explore the torsional potentials for hydroxyacetone using second order Møller‐Plesset (MP2) and coupled‐cluster (CCSD(T)) ab initio theoretical methods. We have calculated these potential energy surfaces as a function of single OH rotation, and simultaneous OH and methyl rotation. The results indicate that the low energy isomers coupled to the reduced barrier to methyl rotation can lead to several rotamers for this species to form. The values are compared to experimental quantities and implications for astrobiological research are also addressed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 相似文献