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961.
Andrews ZB 《Peptides》2011,32(11):2248-2255
Ghrelin is a stomach hormone, secreted into the bloodstream, that initiates food intake by activating NPY/AgRP neurons in the hypothalamic acruate nucleus. This review focuses on recent evidence that details the mechanisms through which ghrelin activate receptors on NPY neurons and downstream signaling within NPY neurons. The downstream signaling involves a novel CaMKK-AMPK-CPT1-UCP2 pathway that enhances mitochondrial efficiency and buffers reactive oxygen species in order to maintain an appropriate firing response in NPY. Recent evidence that shows metabolic status affects ghrelin signaling in NPY is also described. In particular, ghrelin does not activate NPY neurons in diet-induced obese mice and ghrelin does not increase food intake. The potential mechanisms and implications of ghrelin resistance are discussed. 相似文献
962.
Fazeli A Liew CG Matin MM Elliott S Jeanmeure LF Wright PC Moore H Andrews PW 《The International journal of developmental biology》2011,55(2):175-180
Upon prolonged culture, human embryonic stem (hES) cells undergo adaptation, exhibiting decreased population doubling times and increased cloning efficiencies, often associated with karyotypic changes. To test whether culture adaptation influences the patterns of differentiation of hES cells, we compared the expression of genes indicative of distinct embryonic lineages in the embryoid bodies produced from two early passage, karyotypically normal hES cell lines, and two late passage, karyotypically abnormal hES cell lines. One of the abnormal lines was a subline of one of the normal early passage lines. The embryoid bodies from each of the lines showed evidence of extensive differentiation. However, there were differences in the expression of several genes, indicating that the culture adapted hES cells show altered patterns of differentiation compared to karyotypically normal hES cells. The loss of induction of alphafetoprotein in the culture-adapted cells was especially marked, suggesting that they had a reduced capacity to produce extra-embryonic endoderm. These changes may contribute to the growth advantages of genetically variant cells, not only by reflecting an increased tendency to self renewal rather than to differentiate, but also by reducing spontaneous differentiation to derivatives that themselves may produce factors that could induce further differentiation of undifferentiated stem cells. 相似文献
963.
Hsu WS Erickson SL Tsai HJ Andrews CA Vas AC Clarke DJ 《Molecular and cellular biology》2011,31(12):2470-2483
Genome stability depends on faithful chromosome segregation, which relies on maintenance of chromatid cohesion during S phase. In eukaryotes, Pds1/securin is the only known inhibitor that can prevent loss of cohesion. However, pds1Δ yeast cells and securin-null mice are viable. We sought to identify redundant mechanisms that promote cohesion within S phase in the absence of Pds1 and found that cells lacking the S-phase cyclins Clb5 and Clb6 have a cohesion defect under conditions of replication stress. Similar to the phenotype of pds1Δ cells, loss of cohesion in cells lacking Clb5 and Clb6 is dependent on Esp1. However, Pds1 phosphorylation by Cdk-cyclin is not required for cohesion. Moreover, cells lacking Clb5, Clb6, and Pds1 are inviable and lose cohesion during an unperturbed S phase, indicating that Pds1 and specific B-type cyclins promote cohesion independently of one another. Consistent with this, we find that Mcd1/Scc1 is less abundant on chromosomes in cells lacking Clb5 and Clb6 during replication stress. However, clb5Δ clb6Δ cells do accumulate Mcd1/Scc1 at centromeres upon mitotic arrest, suggesting that the cyclin-dependent mechanism is S phase specific. These data indicate that Clb5 and Clb6 promote cohesion which is then protected by Pds1 and that both mechanisms are required during replication stress. 相似文献
964.
965.
966.
Andrews MD Fish PV Blagg J Brabham TK Brennan PE Bridgeland A Brown AD Bungay PJ Conlon KM Edmunds NJ af Forselles K Gibbons CP Green MP Hanton G Holbrook M Jessiman AS McIntosh K McMurray G Nichols CL Root JA Storer RI Sutton MR Ward RV Westbrook D Whitlock GA 《Bioorganic & medicinal chemistry letters》2011,21(9):2715-2720
New pyrimido[4,5-d]azepines 7 are disclosed as potent 5-HT2C receptor agonists. A preferred example, 7b had minimal activation at either the 5-HT2A or 5-HT2B receptors combined with robust efficacy in a preclinical canine model of stress urinary incontinence (SUI) and attractive pharmacokinetic and safety properties. Based on this profile, 7b (PF-3246799) was identified as a candidate for clinical development for the treatment of SUI. In addition, it proved to be critical to build an understanding of the translation between recombinant cell-based systems, native tissue preparations and in vivo preclinical models. This was a significant undertaking and proved to be crucial in compound selection. 相似文献
967.
Andrews KM Beebe DA Benbow JW Boyer DA Doran SD Hui Y Liu S McPherson RK Neagu C Parker JC Piotrowski DW Schneider SR Treadway JL VanVolkenberg MA Zembrowski WJ 《Bioorganic & medicinal chemistry letters》2011,21(6):1810-1814
A 3-amino-4-substituted pyrrolidine series of dipeptidyl peptidase IV (DPP-4) inhibitors was rapidly developed into a candidate series by identification of a polar valerolactam replacement for the lipophilic 2,4,5-trifluorophenyl pharmacophore. The addition of a gem-difluoro substituent to the lactam improved overall DPP-4 inhibition and an efficient asymmetric route to 3,4-diaminopyrrolidines was developed. Advanced profiling of a subset of analogs identified 5o with an acceptable human DPP-4 inhibition profile based on a rat PK/PD model and a projected human dose that was suitable for clinical development. 相似文献
968.
Cheshire DR Åberg A Andersson GM Andrews G Beaton HG Birkinshaw TN Boughton-Smith N Connolly S Cook TR Cooper A Cooper SL Cox D Dixon J Gensmantel N Hamley PJ Harrison R Hartopp P Käck H Leeson PD Luker T Mete A Millichip I Nicholls DJ Pimm AD St-Gallay SA Wallace AV 《Bioorganic & medicinal chemistry letters》2011,21(8):2468-2471
By careful analysis of experimental X-ray ligand crystallographic protein data across several inhibitor series we have discovered a novel, potent and selective series of iNOS inhibitors exemplified by compound 8. 相似文献
969.
Peterson EA Andrews PS Be X Boezio AA Bush TL Cheng AC Coats JR Colletti AE Copeland KW DuPont M Graceffa R Grubinska B Harmange JC Kim JL Mullady EL Olivieri P Schenkel LB Stanton MK Teffera Y Whittington DA Cai T La DS 《Bioorganic & medicinal chemistry letters》2011,21(7):2064-2070
mTOR is part of the PI3K/AKT pathway and is a central regulator of cell growth and survival. Since many cancers display mutations linked to the mTOR signaling pathway, mTOR has emerged as an important target for oncology therapy. Herein, we report the discovery of triazine benzimidazole inhibitors that inhibit mTOR kinase activity with up to 200-fold selectivity over the structurally homologous kinase PI3Kα. When tested in a panel of cancer cell lines displaying various mutations, a selective inhibitor from this series inhibited cellular proliferation with a mean IC50 of 0.41 μM. Lead compound 42 demonstrated up to 83% inhibition of mTOR substrate phosphorylation in a murine pharmacodynamic model. 相似文献
970.
Xu M Andrews KT Birrell GW Tran TL Camp D Davis RA Quinn RJ 《Bioorganic & medicinal chemistry letters》2011,21(2):846-848
Mass-directed isolation of the CH2Cl2/CH3OH extract from a marine sponge of the genus Pseudoceratina resulted in the purification of a new antimalarial bromotyrosine alkaloid, psammaplysin H (1), along with the previously isolated analogs psammaplysins G (2) and F (3). The structure of 1 was elucidated following 1D and 2D NMR, and MS data analysis. All compounds were tested in vitro against the 3D7 line of Plasmodium falciparum and mammalian cell lines (HEK293 and HepG2), with 1 having the most potent (IC50 0.41 μM) and selective (>97-fold) antimalarial activity. 相似文献