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1.
Fatty acid-amino acid conjugates (FACs) have been identified in Lepidopteran larvae as elicitors of plant defenses. Plant responses include the production of primary defense compounds and induction of secondary defense strategies including attraction of parasitoid wasps. These elicitors are present despite fitness costs, suggesting that they are important for the larvae’s survival. In order to exploit FAC-mediated plant defense responses in agricultural settings, an understanding of FAC purpose and metabolism is crucial. To clarify their role, enzymes involved in this metabolism are being investigated. In this work a previously undiscovered FAC hydrolase was purified from Heliothis virescens frass by liquid chromatography and PAGE techniques and was identified as an aminoacylase-like protein (L-ACY-1) using MALDI-ToF/ToF and Edman sequencing. The full length gene was cloned and expressed in Escherichia coli and a polyclonal antibody against L-ACY-1 was made. L-ACY-1 was confirmed to be responsible for FAC hydrolysis activity through inhibition of N-linolenoyl-l-glutamine hydrolysis by titration with the polyclonal anti-L-ACY-1 antibody. L-ACY-1 activity is dependent on a divalent cation. This is the first time an aminoacylase has been described from an insect. L-ACY-1 appears to play a vastly different role in insects than ACYs do in mammals and may be involved in maintaining glutamine supplies for gut tissue metabolism. Identification of L-ACY-1, a FAC hydrolase, clarifies a previously uncharacterized portion of FAC metabolism.  相似文献   
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IL‐18 is known to play a key role limiting Cryptosporidium parvum infection. In this study, we show that IL‐18 depletion in SCID mice significantly exacerbates C. parvum infection, whereas, treatment with recombinant IL‐18 (rIL‐18), significantly decreases the parasite load, as compared to controls. Increases in serum IFN‐γ levels as well as the up‐regulation of the antimicrobial peptides, cathelicidin antimicrobial peptide and beta defensin 3 (Defb3) were observed in the intestinal mucosa of mice treated with rIL‐18. In addition, C. parvum infection significantly increased mRNA expression levels (> 50 fold) of the alpha defensins, Defa3 and 5, respectively. Interestingly, we also found a decrease in mRNA expression of IL‐33 (a recently identified cytokine in the same family as IL‐18) in the small intestinal tissue from mice treated with rIL‐18. In comparison, the respective genes were induced by IL‐18 depletion. Our findings suggest that IL‐18 can mediate its protective effects via different routes such as IFN‐γ induction or by directly stimulating intestinal epithelial cells to increase antimicrobial activity.  相似文献   
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Spinal muscular atrophy (SMA) is a heterogeneous group of neuromuscular disorders caused by degeneration of lower motor neurons. Although functional loss of SMN1 is associated with autosomal-recessive childhood SMA, the genetic cause for most families affected by dominantly inherited SMA is unknown. Here, we identified pathogenic variants in bicaudal D homolog 2 (Drosophila) (BICD2) in three families afflicted with autosomal-dominant SMA. Affected individuals displayed congenital slowly progressive muscle weakness mainly of the lower limbs and congenital contractures. In a large Dutch family, linkage analysis identified a 9q22.3 locus in which exome sequencing uncovered c.320C>T (p.Ser107Leu) in BICD2. Sequencing of 23 additional families affected by dominant SMA led to the identification of pathogenic variants in one family from Canada (c.2108C>T [p.Thr703Met]) and one from the Netherlands (c.563A>C [p.Asn188Thr]). BICD2 is a golgin and motor-adaptor protein involved in Golgi dynamics and vesicular and mRNA transport. Transient transfection of HeLa cells with all three mutant BICD2 cDNAs caused massive Golgi fragmentation. This observation was even more prominent in primary fibroblasts from an individual harboring c.2108C>T (p.Thr703Met) (affecting the C-terminal coiled-coil domain) and slightly less evident in individuals with c.563A>C (p.Asn188Thr) (affecting the N-terminal coiled-coil domain). Furthermore, BICD2 levels were reduced in affected individuals and trapped within the fragmented Golgi. Previous studies have shown that Drosophila mutant BicD causes reduced larvae locomotion by impaired clathrin-mediated synaptic endocytosis in neuromuscular junctions. These data emphasize the relevance of BICD2 in synaptic-vesicle recycling and support the conclusion that BICD2 mutations cause congenital slowly progressive dominant SMA.  相似文献   
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Zusammenfassung Die teratologischen Korollblätter vonMalus prunifolia sind, wie die Analyse des äußeren Baues und der Gefäßbündelanordnung ergibt, hypopeltat-schlauchförmig gebaut und verkörpern eine bisher unbekannte Variante des hypopeltaten Spreitenbaues, welcher eine Umkehrung des epipeltaten Blattbaues darstellt. Die hypopeltaten Korollblätter sind durch den Besitz eines superunifazialen Stielabschnitts und einer dorsalen Querzone gekennzeichnet, auf deren Auswachsen die mehr oder weniger große Pseudodorsalspreite zurückzuführen ist. Pseudodorsalspreite und Pseudoventralspreite bilden den abaxial liegenden Spreitentrichter. Die Anordnung der Gefäßbündel der hypopeltaten Korollblätter ist genau umgekehrt wie die epipeltater Blätter, nämlich evers.Die hypopeltate Gestalt der teratologischen Korollblätter stellt nichts anderes als eine Weiterentwicklung der subhypopeltaten Anlage der jungen normalen Kronblätter dar. Durch diese Tendenz zu subhypopeltatem bzw. manifest hypopeltatem Bau sind die Kronblätter scharf von den epipeltat-schlauchförmigen und -diplophyllen verbildeten Staubblättern geschieden, die manchmal beiMalus prunifolia auftreten. Diese hypopeltaten Blätter haben also nichts mit einer etwaigen hypopeltaten Staubblattform zu tun.Herrn Prof. Dr. L.Geitler möchte ich für sein freundliches Entgegenkommen, durch das ich diese Arbeit in seinem Institut fertigstellen konnte, herzlich danken.  相似文献   
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Floral scent is a key mediator in many plant–pollinator interactions. It is known to vary not only among plant species, but also within species among populations. However, there is a big gap in our knowledge of whether such variability is the result of divergent selective pressures exerted by a variable pollinator climate or alternative scenarios (e.g., genetic drift). Cypripedium calceolus is a Eurasian deceptive lady’s-slipper orchid pollinated by bees. It is found from near sea level to altitudes of 2500 m. We asked whether pollinator climate and floral scents vary in a concerted manner among different altitudes. Floral scents of four populations in the Limestone Alps were collected by dynamic headspace and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Flower visitors and pollinators (the subset of visitors with pollen loads) were collected and identified. Preliminary coupled gas chromatographic and electroantennographic measurements with floral scents and pollinators revealed biologically active components. More than 70 compounds were detected in the scent samples, mainly aliphatics, terpenoids, and aromatics. Although several compounds were found in all samples, and all samples were dominated by linalool and octyl acetate, scents differed among populations. Similarly, there were strong differences in flower visitor spectra among populations with most abundant flower visitors being bees and syrphid flies at low and high altitudes, respectively. Pollinator climate differed also among populations; however, independent of altitude, most pollinators were bees of Lasioglossum, Andrena, and Nomada. Only few syrphids acted as pollinators and this is the first record of flies as pollinators in C. calceolus. The electrophysiological tests showed that bees and syrphid flies sensed many of the compounds released by the flowers, among them linalool and octyl acetate. Overall, we found that both floral scent and visitor/pollinator climate differ among populations. We discuss whether interpopulation variation in scent is a result of pollinator-mediated selection.  相似文献   
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Amrein I  Lipp HP 《Biology letters》2009,5(1):141-144
Substantial production of new neurons in the adult mammalian brain is restricted to the olfactory system and the hippocampal formation. Its physiological and behavioural role is still debated. By comparing adult hippocampal neurogenesis (AHN) across many mammalian species, one might recognize a common function. AHN is most prominent in rodents, but shows considerable variability across species, being lowest or missing in primates and bats. The latter finding argues against a critical role of AHN in spatial learning and memory. The common functional denominator across all species investigated thus far is a strong decline of AHN from infancy to midlife. As predicted by Altman and colleagues in 1973, this implies a role in transforming juvenile unpredictable to predictable behaviour, typically characterizing mammalian behaviour once reproductive competence has been attained. However, as only a fraction of mammalian species has been investigated, further comparative studies are necessary in order to recognize whether AHN has a common unique function, or whether it mediates species-specific hippocampal functions.  相似文献   
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Mu- and m-calpain are cysteine proteases requiring micro- and millimolar Ca2+ concentrations for their activation in vitro. Among other mechanisms, interaction of calpains with membrane phospholipids has been proposed to facilitate their activation by nanomolar [Ca2+] in living cells. Here the interaction of non-autolysing, C115A active-site mutated heterodimeric human mu-calpain with phospholipid bilayers was studied in vitro using protein-to-lipid fluorescence resonance energy transfer and surface plasmon resonance. Binding to liposomes was Ca2+-dependent, but not selective for specific phospholipid head groups. [Ca2+]0.5 for association with lipid bilayers was not lower than that required for the exposure of hydrophobic surface (detected by TNS fluorescence) or for enzyme activity in the absence of lipids. Deletion of domain V reduced the lipid affinity of the isolated small subunit (600-fold) and of the heterodimer (10- to 15-fold), thus confirming the proposed role of domain V for membrane binding. Unexpectedly, mutations in the acidic loop of the 'C2-like' domain III, a putative Ca2+ and phospholipid-binding site, did not affect lipid affinity. Taken together, these results support the hypothesis that in vitro membrane binding of mu-calpain is due to the exposed hydrophobic surface of the active conformation and does not reduce the Ca2+ requirement for activation.  相似文献   
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