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131.
The cranial anatomy of Chinese placodonts and the phylogeny of Placodontia (Diapsida: Sauropterygia)
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James M. Neenan Chun Li Olivier Rieppel Torsten M. Scheyer 《Zoological Journal of the Linnean Society》2015,175(2):415-428
Placodonts are Triassic marine reptiles that inhabited the eastern and western margins of the Tethys Ocean (modern South China and Europe/Middle East). Although the crania of European taxa are relatively well understood, those of Chinese taxa have not been extensively studied, and most of them have not been incorporated into a comprehensive phylogeny. Here we present the first reconstructions of all known Chinese placodont holotype skulls using micro‐computed tomographic (μCT) scanning and/or detailed anatomical study. We also present the first phylogenetic analyses that incorporate all placodont genera using a general diapsid matrix that includes postcranial characters, and a placodont‐only cranial matrix. Results vary between the matrices; however, both support a monophyletic Placodontia with eastern taxa interspaced throughout, indicating no major separation between the eastern and western Tethyan realms. Support is strong for a western Tethyan origin of Placodontia, although the highly nested Placochelyidae first appear in the upper Middle Triassic of the eastern Tethys. Thus, all placodont clades appear to have originated in a period of intense speciation during the Middle Triassic. © 2015 The Linnean Society of London 相似文献
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133.
Johnsen L Flåtten I Morigen Dalhus B Bjørås M Waldminghaus T Skarstad K 《Molecular microbiology》2011,79(2):433-446
Escherichia coli cells with a point mutation in the dnaN gene causing the amino acid change Gly157 to Cys, were found to underinitiate replication and grow with a reduced origin and DNA concentration. The mutant β clamp also caused excessive conversion of ATP-DnaA to ADP-DnaA. The DnaA protein was, however, not the element limiting initiation of replication. Overproduction of DnaA protein, which in wild-type cells leads to over-replication, had no effect in the dnaN(G157C) mutant. Origins already opened by DnaA seemed to remain open for a prolonged period, with a stage of initiation involving β clamp loading, presumably limiting the initiation process. The existence of opened origins led to a moderate SOS response. Lagging strand synthesis, which also requires loading of the β clamp, was apparently unaffected. The result indicates that some aspects of β clamp activity are specific to the origin. It is possible that the origin specific activities of β contribute to regulation of initiation frequency. 相似文献
134.
Matias Pasquali Marco Beyer Torsten Bohn Lucien Hoffmann 《Journal of Phytopathology》2011,159(10):700-704
Genetic chemotyping is an essential tool for characterizing Fusarium populations causing head blight on wheat and other cereals. Three PCR methods, based on tri cluster polymorphism, were optimized and compared on 94 single‐spore isolates obtained from three continents belonging to F. gramineaurm, F. culmorum, F. poae, F. avenaceum and Microdochium nivale. While the methods based on the tri3, tri7 and tri12 polymorphism correctly identified all the tested strains, the method based on tri13 polymorphism was unable to discriminate between the 3‐ and 15‐acetylated DON forms in F. graminearum. It is advised to avoid the use of tri13 polymorphism for genetic chemotyping of the two acetylated chemotypes. 相似文献
135.
Guhl S Artuc M Neou A Babina M Zuberbier T 《Bioscience, biotechnology, and biochemistry》2011,75(2):382-384
Human skin mast cells proliferated in the presence of interleukin (IL)-4+SCF (expanding 18-fold in 8 weeks) and acquired profound responsiveness towards high affinity IgE receptor (FcεRI) cross-linking, liberating about 75% of their histamine. In a proof-of-concept, we found that these cells are useful for pharmacological testing. Even a subtle inhibition of degranulation can be visualized. This model might prove valuable in tests of novel anti-allergic drugs. 相似文献
136.
Sielaff F Than ME Bevec D Lindberg I Steinmetzer T 《Bioorganic & medicinal chemistry letters》2011,21(2):836-840
A novel series of amidinohydrazone-derived furin inhibitors was prepared; the most potent compounds 17 and 21 inhibit furin with Ki values of 0.46 and 0.59 μM, respectively. In contrast to inhibitor 17, which still contains a guanidino residue, compound 21 possesses only weakly basic amidinohydrazone groups. 相似文献
137.
Sielaff F Böttcher-Friebertshäuser E Meyer D Saupe SM Volk IM Garten W Steinmetzer T 《Bioorganic & medicinal chemistry letters》2011,21(16):4860-4864
A series of substrate analogue inhibitors of the serine protease HAT, containing a 4-amidinobenzylamide moiety as the P1 residue, was prepared. The most potent compounds possess a basic amino acid in the d-configuration as P3 residue. Whereas inhibitor 4 (Ki 13 nM) containing proline as the P2 residue completely lacks selectivity, incorporation of norvaline leads to a potent inhibitor (15, Ki 15 nM) with improved selectivity for HAT in comparison to the coagulation proteases thrombin and factor Xa or the fibrinolytic plasmin. Selected inhibitors were able to suppress influenza virus replication in a HAT-expressing MDCK cell model. 相似文献
138.
Jackson RW LaPorte MG Herbertz T Draper TL Gaboury JA Rippin SR Patel R Chunduru SK Benetatos CA Young DC Burns CJ Condon SM 《Bioorganic & medicinal chemistry letters》2011,21(11):3227-3231
We describe the structure-activity relationship of the C7-position of pyrano[3,4-b]indole-based inhibitors of HCV NS5B polymerase. Further exploration of the allosteric binding site led to the discovery of the significantly more potent compounds 13 and 14. 相似文献
139.
Previously, a dominant role of the adaptive immune system in the pathogenesis of Sj?gren's syndrome was suspected. Recent
advances, however, have revealed a major role of the type I IFN pathway, documented by an increased circulating type I IFN
activity and an IFN 'signature' in peripheral blood mononuclear cells and minor salivary gland biopsies from the patients.
Polymorphisms in the genes IRF5 and STAT4 leading to increased IFN activation are associated with disease susceptibility. In the pathogenesis of Sj?gren's syndrome,
the activation of salivary gland epithelial cells appears to be the initial event. Once intrinsically activated, they express
costimulatory and Toll-like receptors (TLRs) and MHC class I and II molecules, can present autoantigens and produce proinflammatory
cytokines. The subsequent activation of plasmacytoid dendritic cells induces the production of high levels of proinflammatory
cytokines in individuals with the risk alleles of the susceptibility genes IRF5 and STAT4. Under the influence of the high IFN concentration in the glands and through TLR ligation, B-cell activating factor is produced
by epithelial cells and, together with autoantigen presentation on salivary gland epithelial cells, stimulates the adaptive
immune system. In view of the central role of IFNalpha in at least the initiation of the pathogenesis of Sj?gren's syndrome,
blockade of this cytokine may be a rational therapeutic approach. 相似文献
140.