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111.
Properties of serial kanban systems 总被引:1,自引:0,他引:1
Sridhar R. Tayur 《Queueing Systems》1992,12(3-4):297-318
In this paper we show some structural results of a kanban system by using results about the underlying GSMP. The main results from this connection are: dominance of allocations, optimal partition, upper and lower bounds on throughput, consistency of the IPA derivative, convexity of throughput as a function of service time parameters and concavity of throughput with respect to number of kanbans. Although the dominance and the partition results were obtained previously by sample path arguments, the proofs here are less cumbersome and generalize the earlier results. The second-order properties for kanban lines are new. These results form a basis for results in multi-product lines where proofs by sample paths require extensive notation. 相似文献
112.
113.
Boyapati M. Choudary Chidara Sridhar Mannepalli L. Kantam Bojja Sreedhar 《Tetrahedron letters》2004,45(39):7319-7321
The coupling of three-components, namely an aldehyde, an alkyne and an amine to prepare propargylamines was performed using copper exchanged hydroxyapatite (CuHAP) as the catalyst under mild reaction conditions and in the absence of any co-catalyst. A variety of aldehydes and amines were converted to the corresponding propargylamines, demonstrating the versatility of the reaction. CuHAP was recovered quantitatively by simple filtration and reused several times. 相似文献
114.
115.
Sridhar K 《Physical review letters》1996,77(24):4880-4883
116.
117.
K. Srinivas Sanyasi Sitha B. Sridhar V. Jayathirtha Rao K. Bhanuprakash K. Ravikumar 《Structural chemistry》2006,17(6):561-568
In order to study the keto and enol forms of cyanuric acid derivatives in the solid state, we have synthesized bis(2,4-benzyloxy)-6-(5H)-one-1,3,5-triazine, 1. Computational investigations indicate that keto form is more stable than enol form in both gas phase and solution phase
by 9.69–11.18 kcal mol−1 IR and crystallographic analysis shows that 1 exists in keto form in the solid state also. To obtain the enol form in the solid state, we adopted co-crystallization with
an organic base. The crystal structures of both keto/amine and the enol/imine forms (in a co-crystal) are reported.
IICT Communication No. 2505/CMM-0022. 相似文献
118.
A new and efficient synthesis of a variety of highly embellished bicyclooctenones having an endo-vinyl moiety and their sigmatropic shifts in ground and excited states leading to a stereoselective route to substituted cis-decalins and diquinane frameworks have been described. Functionalized bicyclo[2.2.2]octenones having an endo-vinyl group and a beta,gamma-enone chromophore were prepared by in situ generation of 6-chloromethyl-6-hydroxycyclohexadienones and cycloaddition with butadiene (also generated in situ) followed by manipulation of the adducts. The presence of contiguous carbonyl, hydroxyl, and chloromethyl groups in adducts led to the introduction of various alkyl groups alpha to the ketone in a stereoselective fashion. The 3,3-sigmatropic shift in the bridged bicyclic compounds gave the corresponding cis-decalins, whereas the triplet sensitized irradiation led to the formation of diquinanes as a result of a 1,2-acyl shift. 相似文献
119.
Balasubramanian Sridhar Krishnan Ravikumar 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):o415-o418
In the title compounds, C5H6N5+·C8H7O2−·C8H8O2·H2O, (I), and C5H6N5+·C4H3O4−·H2O, (II), the adeninium cations form N—H...O hydrogen bonds with their anion counterparts and adeninium–adeninium self‐association base pairs with the R22(10) motif (Bernstein et al., 1995). A complete hydrogen‐bonding motif analysis is presented. Conventional hydrogen bonds lead to layer structures in (I) and to two‐dimensional infinite polymeric ribbons in (II). C—H...O interactions are found in both structures, while weak π–π stacking interactions are only observed in (I). 相似文献
120.
G. Y. S. K. Swamy K. Ravikumar B. Sridhar I. Mahender K. V. N. S. Srinivas 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o495-o497
The title compound [systematic name: 5‐hydroxy‐2‐(3‐hydroxy‐4,5‐dimethoxyphenyl)‐3,6,7‐trimethoxy‐4H‐chromen‐4‐one], C20H20O9, was isolated from the seeds of Cleom viscosa Linn. Two independent molecules (A and B) are present in the asymmetric unit with almost similar conformations. The dihedral angles between the fused chromene ring system and the benzene ring bonded to it in molecules A and B are 4.2 (1) and 12.7 (1)°, respectively. The hydroxy O atoms are involved in intramolecular hydrogen bonding. The molecules are linked by C—H⋯O and O—H⋯O interactions into chains of edge‐fused R33(22) rings. Aromatic π–π and weak C—H⋯π(arene) interactions are also observed. 相似文献