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401.
The crystals of tetramethylammonium triiodolead(II) are hexagonal with = 9.7823(11) A, c = 7.9167(8) A and γ = 120.0, Z = 2, space group P63/m. The structure was solved by direct methods and refined by least-squares techniques to a conventional R = 2.97% for the 312 independent reflections. The structure consists of chains of PbI3 units running along the c axis. Each lead atom is octahedrally coordinated to six iodides with a Pb---I bond distance of 3.223 A. The tetramethylammonium cations sit in holes in the packing of the iodide ions. The cations are disordered.
The Raman spectra of salts of this species formed with several tetraalkylammonium cations are also reported and the bands tentatively assigned. 相似文献
402.
Trino Suárez Bernardo Fontal Marisela Reyes Fernando Bellandi Ricardo Contreras Gustavo León Pedro Cancines 《Reaction Kinetics and Catalysis Letters》2002,76(1):161-169
A synthetic route is reported for the water soluble complex RuCl(h5- C5H5)(TPPMS)2(1), (TPPMS = (C6H5)2P(C6H4-m-SO3Na) and characterized by UV-Vis, FTIR, 1H, 13C NMR and GC-MS. Complex 1 is a good catalytic precursor in biphasic media (toluene/ water) for 1-hexene hydrogenation under moderate reaction conditions (e.g. 500 psi H2, 100°C) giving good yields of n-hexane, and smaller amounts of cis-2-hexene and trans-2-hexene. Other organic substrates (cinnamaldehyde, crotonaldehyde, cyclohexene, acetone and butylaldehyde) are hydrogenated. 相似文献
403.
Norberto Farfn J. Manuel Hernndez Pedro Joseph-Nathan Rosalinda Contreras 《Journal of heterocyclic chemistry》1990,27(6):1745-1749
Reaction of N-methylaniline with 40% glyoxal yields 1-methyl-2-(N-methyl-N-phenylglycyl)-3-(N-methylanilino)indole ( 1a ) as the main product together with 1-methyl-3-(N-methylanilino)indole ( 1b ). The reaction appears to be general for aromatic secondary amines since N-ethylaniline and N-phenylbenzylamine yield the corresponding indoles. The structure of 1a has been verified by single crystal X-ray diffraction. Compound 1a (C25H25N3O) crystallized in the triclinic space group Pl? with cell dimensions a = 10.085(3)Å, b = 10.371(3)Å, c = 11.908(5)Å, α = 74.2(3)°, β = 74.7(3)° and γ = 60.7(2)° with Z = 2. The complete 1H and 13C nmr assignment of indoles 1a and 1b was achieved from two-dimensional HETCOR and COSY spectra with the aid of homonuclear and heteronuclear double resonance experiments. 相似文献
404.
The self-consistent perturbation theory is used to calculate noncontract contributions to spin–spin coupling constants involving protons. Molecular wave functions were obtained with a modified version of the INDO method which includes hydrogen 2p orbitals in its basis set. It is found that in many cases the orbital and dipolar terms are by no means negligible, being particularly important in geminal H? H couplings. Results reported in this paper for this type of coupling, reproduce experimental trends in the series CH4, NH3, and OH2. In general, noncontact terms are found to decrease as the number of bonds separating the interacting nuclei increases. 相似文献
405.
Norah Barba-Behrens Fabián Salazar-García Angélica Mara Bello-Ramírez Efrén García-Báez María de Jesús Rosales-Hoz Rosalinda Contreras Angelina Flores-Parra 《Transition Metal Chemistry》1994,19(6):575-581
Summary The synthesis and characterization of the following coordination compounds derived from quinic acid (quin) (1): [Cu(quin)Cl(H2O)]n·(H2O)n(2); [Ni(quin)Cl(H2O)]n·(2H2O) n (3); [Co(quin) Cl(H2O)]n·(2H2O)n(4); [Cu(quin) (NO3)(H2O)]n·(2H2O)n(5); [Cu(quin)(AcO)(H2O)]n· (2H2O)n(6); [Cu(quin)H2O]2·2H2O(7); [Co(quin)2]n (8); [Zn(quin)2](9); [Cd(quin)2](10) and [Hg(quin)2]· 4H2O (11) is presented. All of the compounds were characterized by i.r. and u.v. spectroscopy; in addition, (9) and (10) were analysed by n.m.r., and (2), (5) and (7) by X-ray crystallography. Due to the polyfunctionality of quinic acid diverse structures were obtained: (2) –(6) and (8) were polymeric, (7) was dimeric and (9) –(11) were spiranic. In compound (2) the Cu had a distorted octahedral structure; it was a chiral centre with six different substituents and an optically active ligand. Only one stereoisomer (OC-6-25-A) of the 30 possible was observed in the crystal. Compound (5) was also polymeric, the hexacoordinated Cu atom was a chiral centre (OC-6-53C) and only one stereoisomer was observed. It was bonded to three quinic acid ligands in three different coordination modes and each quinic acid was in turn bonded to three different Cu atoms. Each chain was linked to another two chains giving a net structure. Compound (7) was a dimer with two square pyramidal Cu atoms. Two apical water molecules were found in acis arrangement. Each quinic acid ligand was bonded to two Cu atoms which were linked by two oxygen bridges and each Cu atom was bonded to two quinic acid moieties. 相似文献
406.
Contreras C Román R Pérez C Alarcón F Zavala M Pérez S 《Chemical & pharmaceutical bulletin》2005,53(11):1408-1410
A new ulopyranose isolated from aqueous extract of roots and rhizomas of Psacalium peltatum has been determined to have hypoglycemic activity at doses of 100 mg/kg, comparable to that of tolbutamide and insulin in alloxan diabetic mice. The skeletal structure of the new compound was established by spectral analysis. 相似文献
407.
Reversible adsorption isotherms at different temperatures have been used to study the system of water adsorbed on Aerosil and on Aerosil whose surface has been partially methylated with trimethylchlorosilane.The change in the shape of the isotherm upon surface methylation from type II to type III, according to Brunauer's classification, renders difficult the calculation of the capacity of the monolayer; however, in this case it can be obtained by Kaganer's method.The variation in the mobility of the monolayer on surface methylation can be shown by comparing the experimental and theoretical integral entropies, while the molecules adsorbed in the multilayer region always have a high degree of freedom. 相似文献
408.
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
409.
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
410.
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