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201.
(Pivaloyloxy)methyl 6,6-dihalo-, 6-monosubstituted- and 6-halo 1,1-dioxide penicillanates, N-benzoylglycine methyl ester and several selected esters are efficiently hydrolyzed with bis(tributyltin) oxide (nBu3Sn)2O with yields from 43 to 100%. 相似文献
202.
Harri Takalo Veli-Matti Mukkala Liisa Meri Juan Carlos Rodríguez-Ubis Rosa Sedano Olga Juanes Ernesto Brunet 《Helvetica chimica acta》1997,80(2):372-387
The synthesis of novel TbIII labels suitable for protein labelling are reported. Their luminescence properties as antibody conjugates were measured and compared to the results of corresponding TbIII chelates of the parent ligand structures. When the lowest triplet-state energy level of the parent donor ligand was over 23000 cm?1, i.e., the energy gap between the 5D4 level of TbIII and the lowest triplet-state energy level of the ligand exceeded 2600 cm?1, the label derivative with a long decay time (τ = 1.35–2.93 ms) and a high luminescence yield (?. Φ = 3770–4560) was found to be suitable for bioaffinity assays. 相似文献
203.
[reaction: see text] The reaction of 3-azido-2,3-dideoxy-hexopyranose compounds from the d-gluco, d-galacto, d-lacto, and l-arabino carbohydrate series, with (diacetoxyiodo)benzene and iodine, generated 2-azido-1,2-dideoxy-1-iodo-alditols with one carbon less than the starting carbohydrate. These beta-iodo azides could be transformed by dehydroiodination into vinyl azides, which in turn afforded 3-monosubstituted 2H-azirines under thermal conditions. These beta-iodo azides and 2H-azirines may be interesting chiral synthons for the preparation of more complex heterocyclic systems. 相似文献
204.
Fullerene reacted with mono- and diphosphonate-bearing bipyridines by way of Bingel-type reactions to give adducts which were easily transformed in the corresponding dyads by forming Ru(bpy)3 complexes. Electrochemical measurements and the observation of heavy quenching of the Ru(bpy)3 luminescence manifested strong interactions between the active moieties. Attempts to include the dyads into inorganic matrices derived from zirconium phosphate are reported. 相似文献
205.
Sotelo E Fraiz N Yáñez M Laguna R Cano E Raviña E 《Chemical & pharmaceutical bulletin》2002,50(12):1574-1577
This paper describes the synthesis and the antiplatelet activity of a series of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones. Some of these compounds show a dose-dependent activity and were found to be more active than their 5-substituted analogues. 相似文献
206.
Cámpora J Maya CM Palma P Carmona E Gutiérrez-Puebla E Ruiz C 《Journal of the American Chemical Society》2003,125(6):1482-1483
The often facile C-/O-tautomerization of transition metal enolates is severely hindered in the cyclic Ni complexes 1 and 2, allowing the study of their individual reactivities. At room temperature only the O-bound tautomer, 2, reacts with aldehydes, giving rise to the corresponding addition products. 相似文献
207.
Occhiato EG Prandi C Ferrali A Guarna A Deagostino A Venturello P 《The Journal of organic chemistry》2002,67(20):7144-7146
Alkoxydienyl- and alkoxystyrylboronates were used for Pd-catalyzed cross-coupling reactions with lactam-derived vinyl triflates. The hydrolysis of the coupling products with alkoxystyrylboronates provided the corresponding alpha-acyl-substituted 3,4-dihydro-(2H)-pyridines and 2,3,4,5-tetrahydroazepines in good to high yields. The hydrolysis of the coupling products with alkoxydienylboronates, performed in the presence of Amberlyst 15, resulted in a Nazarov-type cyclization that afforded hexahydro[1]pyrindin-7-ones and 3,4,5,6,7,8-hexahydro-(2H)-cyclopenta[b]azepin-8-ones. This methodology represents a novel and efficient procedure for the preparation of these classes of azacyclic compounds. 相似文献
208.
Ernesto Schulz Lang Gelson Manzoni de Oliveira Ramo Marceli Fernandes Jr. Ezequiel M. VzquezLpez 《无机化学与普通化学杂志》2004,630(5):717-721
The direct reaction between PhTeCl3 and CsCl in methanol affords {Cs[PhTeCl4]·CH3OH}. Cs[PhTeBr4] was prepared by refluxing [2‐Br‐C5NH5][PhTeBr4] and CsCl in ethanol in the presence of an excess of HBr. In {Cs[PhTeCl4]·CH3OH} the [PhTeCl4]— units form dimers by secondary Te···Cl bonds with methanol molecules bridging adjacent Cs+ cations. In both compounds, the alkali metal cation interacts secondarily with the chlorine and bromine Te‐ligands, achieving singular coordination polyhedrons and holding the lattices in supramolecular tridimensional assemblies. The new complexes, {Cs[PhTeCl4]·CH3OH} and Cs[PhTeBr4], crystallize in the space groups P21/c and P21/n, respectively. Only one such structure has been reported before. 相似文献
209.
[reaction: see text]. The beta-fragmentation of 2,2-difluoro-saccharide anomeric alkoxyl radicals, generated under oxidative condition by treatment of the respective alcohols with (diacetoxyiodo)benzene (DIB) and iodine, afforded 1,1-difluoro-1-iodo alditols in high yield. The reactivity of the fluorinated radical generated by rupture of the C-I bond has been preliminarily assessed by reductive deiodination with tributyltin hydride/AIBN and intermolecular allylation using the Keck reaction. 相似文献
210.
Lucio Forni Elena Selli Ernesto Fumagalli Daniela Mainini 《Reaction Kinetics and Catalysis Letters》1997,61(2):267-273
The poisoning effect of CO2 on a HY catalyst for the dehydration of 2-(2-hydroxyethyl)-pyridine (HEP) to 2-vinylpyridine (VP) has been investigated by
FT-IR analysis in the presence and absence of pyridine. CO2 was found to adsorb on sites not occupied by pyridine,i.e. on weak basic sites accompanying the strongly acidic sites, characteristic of Y zeolites in the protonated form. When the
basic sites are occupied by preadsorbed CO2, HEP dehydration cannot take place any more through the minor mechanism, involving a couple of acid-base sites, and the reaction
proceeds only through the major mechanism, involving a carbocation intermediate, on Br?nsted acid sites only. 相似文献