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991.
Barnes GL Della Torre T Sommer B Young MF Gerstenfeld LC 《Journal of cellular biochemistry》2002,87(4):458-469
This study identifies a cis-acting element that confers tissue-restricted expression to the bone sialoprotein (BSP) gene. Using both gain of function and loss-of function studies, we demonstrate that this element acts as a tissue specific enhancer of BSP expression in osteoblasts and hypertrophic chondrocytes but does not function in non-hypertrophic chondrocytes or fibroblasts. Furthermore, our data demonstrate that binding of this element occurs in correlation with active BSP expression. While Dlx5 has been implicated as the tissue-specific regulator of BSP expression through direct DNA binding at an element with homology to the one under study here, our results demonstrate that Dlx5 does not act as a positive regulator of BSP expression. Finally, mutational analyses of this element demonstrate that while there is homology to putative homeodomain binding elements, this site is unlikely to bind homeodomain factors including Dlx5. Thus, these studies identify an important cis-acting element in the BSP promoter that acts as a tissue-specific enhancer of BSP expression in both osteoblasts and hypertrophic chondrocytes. As such this is the first demonstration of a common regulatory mechanism utilized by both chondrocytes and osteoblasts for the tissue-restricted expression of the BSP gene. 相似文献
992.
Sameith Katrin Amini Saman Groot Koerkamp Marian J. A. van Leenen Dik Brok Mariel Brabers Nathalie Lijnzaad Philip van Hooff Sander R. Benschop Joris J. Lenstra Tineke L. Apweiler Eva van Wageningen Sake Snel Berend Holstege Frank C. P. Kemmeren Patrick 《BMC biology》2015,13(1):1-7
Karrikins are a family of compounds produced by wildfires that can stimulate the germination of dormant seeds of plants from numerous families. Seed plants could have ‘discovered’ karrikins during fire-prone times in the Cretaceous period when flowering plants were evolving rapidly. Recent research suggests that karrikins mimic an unidentified endogenous compound that has roles in seed germination and early plant development. The endogenous signalling compound is presumably not only similar to karrikins, but also to the related strigolactone hormones. 相似文献
993.
Van Remmen H Qi W Sabia M Freeman G Estlack L Yang H Mao Guo Z Huang TT Strong R Lee S Epstein CJ Richardson A 《Free radical biology & medicine》2004,36(12):1625-1634
To examine the effect of compound deficiencies in antioxidant defense, we have generated mice (Sod2+/−/Gpx1−/−) that are deficient in Mn superoxide dismutase (MnSOD) and glutathione peroxidase 1 (Gpx1) by breeding Sod2+/− and Gpx1−/− mice together. Although Sod2+/−/Gpx1−/− mice showed a 50% reduction in MnSOD and no detectable Gpx1 activity in either mitochondria or cytosol in all tissues, they were viable and appeared normal. Fibroblasts isolated from Sod2+/−/Gpx1−/− mice were more sensitive (4- to 6-fold) to oxidative stress (t-butyl hydroperoxide or γ irradiation) than fibroblasts from wild-type mice, and were twice as sensitive as cells from Sod2+/− or Gpx1−/− mice. Whole-animal studies demonstrated that survival of the Sod2+/−/Gpx1−/− mice in response to whole body γ irradiation or paraquat administration was also reduced compared with that of wild-type, Sod2+/−, or Gpx1−/− mice. Similarly, endogenous oxidative stress induced by cardiac ischemia/reperfusion injury led to greater apoptosis in heart tissue from the Sod2+/−/Gpx1−/− mice than in that from mice deficient in either MnSOD or Gpx1 alone. These data show that Sod2+/−/Gpx1−/− mice, deficient in two mitochondrial antioxidant enzymes, have significantly enhanced sensitivity to oxidative stress induced by exogenous insults and to endogenous oxidative stress compared with either wild-type mice or mice deficient in either MnSOD or Gpx1 alone. 相似文献
994.
995.
Marian Irwin 《The Journal of general physiology》1919,1(4):399-403
In petals of Salvia high concentrations of ether cause an increase in oxygen consumption and in the production of CO2, while at the same time a decrease occurs in the acidity of the cell contents. 相似文献
996.
Nowak Kinga Giertych Marian J. Pers-Kamczyc Emilia Thomas Peter A. Iszkuło Grzegorz 《Journal of plant research》2021,134(5):947-962
Journal of Plant Research - Causes of secondary sexual dimorphism (SSD) in dioecious plants are very poorly understood, especially in woody plants. SSD is shown mainly in mature plants, but little... 相似文献
997.
Flaviano Giorgini Shao-Yi Huang Korrapati V. Sathyasaikumar Francesca M. Notarangelo Marian A. R. Thomas Margarita Tararina Hui-Qiu Wu Robert Schwarcz Paul J. Muchowski 《The Journal of biological chemistry》2013,288(51):36554-36566
Kynurenine 3-monooxygenase (KMO), a pivotal enzyme in the kynurenine pathway (KP) of tryptophan degradation, has been suggested to play a major role in physiological and pathological events involving bioactive KP metabolites. To explore this role in greater detail, we generated mice with a targeted genetic disruption of Kmo and present here the first biochemical and neurochemical characterization of these mutant animals. Kmo−/− mice lacked KMO activity but showed no obvious abnormalities in the activity of four additional KP enzymes tested. As expected, Kmo−/− mice showed substantial reductions in the levels of its enzymatic product, 3-hydroxykynurenine, in liver, brain, and plasma. Compared with wild-type animals, the levels of the downstream metabolite quinolinic acid were also greatly decreased in liver and plasma of the mutant mice but surprisingly were only slightly reduced (by ∼20%) in the brain. The levels of three other KP metabolites: kynurenine, kynurenic acid, and anthranilic acid, were substantially, but differentially, elevated in the liver, brain, and plasma of Kmo−/− mice, whereas the liver and brain content of the major end product of the enzymatic cascade, NAD+, did not differ between Kmo−/− and wild-type animals. When assessed by in vivo microdialysis, extracellular kynurenic acid levels were found to be significantly elevated in the brains of Kmo−/− mice. Taken together, these results provide further evidence that KMO plays a key regulatory role in the KP and indicate that Kmo−/− mice will be useful for studying tissue-specific functions of individual KP metabolites in health and disease. 相似文献
998.
G. R. V. Babu J. H. Wolfram J. M. Marian K. D. Chapatwala 《Applied microbiology and biotechnology》1995,43(4):739-745
Pseudomonas marginalis, capable of utilizing acetonitrile as the sole source of carbon and nitrogen, was isolated from an industrial waste site. P. marginalis metabolized acetonitrile into ammonia and acetate. The minimal inhibitory concentration values of different nitriles and amides for P. marginalis were in the range 5–300 mM. The bacterium was able to transform high-molecular-mass nitrile compounds and their respective amides into ammonia. The data from substrate-dependent kinetics showed that the K
m and V
max values of P. marginalis for acetonitrile were 33 mM and 67 nmol oxygen consumed min–1 (ml cell suspension)–1 respectively. The study with [14C]acetonitrile indicated that nearly 66% of the carbon was released as 14CO2 and 12% was associated with the biomass. The enzyme system involved in the hydrolysis of acetonitrile was shown to be intracellular and inducible. The specific activities of the enzymes nitrile aminohydrolase and amidase were determined in the cell-free extracts of P. marginalis. Both the enzymes could hydrolyze a wide range of nitriles and amides. The present study suggests that the biodegradation of organic nitriles and the bioproduction of organic acids may be achieved with the cells of P. marginalis. 相似文献
999.
José Eduardo A.R. Marian 《Journal of morphology》2012,273(3):248-278
During copulation, spermatophores produced by male coleoid cephalopods undergo the spermatophoric reaction, a complex process of evagination that culminates in the attachment of the spermatangium (everted spermatophore containing the sperm mass) on the female's body. To better understand this complicated phenomenon, the present study investigated the functional morphology of the spermatophore of the squid Doryteuthis plei applying in vitro analysis of the reaction, as well as light and electron microscopy investigation of spermatangia obtained either in vitro, or naturally attached on females. Hitherto unnoticed functional features of the loliginid spermatophore require a reappraisal of some important processes involved in the spermatophoric reaction. The most striking findings concern the attachment mechanism, which is not carried out solely by cement adhesive material, as previously believed, but rather by an autonomous, complex process performed by multiple structures during the spermatophoric reaction. During evagination, the ejaculatory apparatus provides anchorage on the targeted tissue, presumably due to the minute stellate particles present in the exposed spiral filament. Consequently, the ejaculatory apparatus maintains the attachment of the tip of the evaginating spermatophore until the cement body is extruded. Subsequently, the cement body passes through a complex structural rearrangement, which leads to the injection of both its viscid contents and pointed oral region onto the targeted tissue. The inner membrane at the oral region of the cement body contains numerous stellate particles attached at its inner side; eversion of this membrane exposes these sharp structures, which presumably adhere to the tissue and augment attachment. Several naturally attached spermatangia were found with their bases implanted at the deposition sites, and the possible mechanisms of perforation are discussed based on present evidence. The function of the complex squid spermatophore and its spermatophoric reaction is revisited in light of these findings. J. Morphol. 2012. © 2011 Wiley Periodicals, Inc. 相似文献
1000.