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491.
Kouadio A. Olivier Koffi N. Konan Felicia N. Anike Georges N. Agbo Hortense W. Dodo 《Plant Cell, Tissue and Organ Culture》2012,109(1):179-189
Two methods were used to produce yam minitubers from two different yam cultivars (cv. Krengle and cv. Kponan) using in vitro
culture techniques. Method 1: Yam microtubers were first initiated in vitro and then transplanted to soil to generate plants
from which minitubers were produced. Yam plants were obtained either by directly planting the microtubers to soil, or by inducing
the germination of the microtubers using various chemical and physical treatments, before their transfer to soil. Method 2:
Yam plantlets were first produced in vitro and then transplanted to soil for further development and tuber production. In
both methods, the presence of jasmonic acid (JA) in the culture medium was found to be essential for yam tuberization, as
well as for the germination of yam microtubers. In vitro production of yam microtubers was variety dependant. Compared to
cv. Krengle, cv. Kponan responded better to microtuberization, and 2.5 μM JA was the optimum concentration resulting in 70
and 90% explants producing microtubers in the MS medium and the Tuberization medium (T-medium), respectively. Germination
of the microtubers required treatment of JA at concentrations ranging from 1.0 to 2.5 μM. The overall length of the process
to produce minitubers from microtubers took 32 weeks. In contrast, minitubers were obtained within 20 weeks when plantlets
were directly transferred to soil. In this case, plantlets were first grown for 8 weeks on medium containing JA (0.1–1.0 μM)
and 8% sucrose to initiate plant growth and rooting. 相似文献
492.
Childs EW Tharakan B Hunter FA Tinsley JH Cao X 《American journal of physiology. Heart and circulatory physiology》2007,292(6):H3179-H3189
Hemorrhagic shock (HS) disrupts the endothelial cell barrier, resulting in microvascular hyperpermeability. Recent studies have also demonstrated that activation of the apoptotic signaling cascade is involved in endothelial dysfunction, which may result in hyperpermeability. Here we report involvement of the mitochondrial "intrinsic" pathway in microvascular hyperpermeability following HS in rats. HS resulted in the activation of the mitochondrial intrinsic pathway, as is evident from an increase in the proapoptotic Bcl-2 family member BAK, release of mitochondrial cytochrome c into the cytoplasm, and activation of caspase-3. This, along with the in vivo transfection of the proapoptotic peptide BAK (BH3), resulted in hyperpermeability (as visualized by intravital microscopy), release of mitochondrial cytochrome c into the cytoplasm, and activation of caspase-3. Conversely, transfection of the BAK (BH3) mutant had no effect on hyperpermeability. Together, these results demonstrate involvement of the mitochondrial intrinsic apoptotic pathway in HS-induced hyperpermeability and that the attenuation of this pathway may provide an alternative strategy in preserving vascular barrier integrity. 相似文献
493.
Annamaria Macchiaroli Daniel Kelberman Renata Simona Auriemma Suzanne Drury Lily Islam Sara Giangiobbe Gabriele Ironi Nicholas Lench Jane C. Sowden Annamaria Colao Rosario Pivonello Luciano Cavallo Maurizio Gasperi Maria Felicia Faienza 《Gene》2014
Heterozygous de novo mutations in SOX2 have been reported in approximately 10–20% of patients with unilateral or bilateral anophthalmia or microphthalmia. An additional phenotype of hypopituitarism, with anterior pituitary hypoplasia and hypogonadotropic hypogonadism, has been reported in patients carrying SOX2 alterations. We report a novel heterozygous mutation in the SOX2 gene in a male affected with congenital bilateral anophthalmia, hypogonadotrophic hypogonadism and growth hormone deficiency. The mutation we describe is a cytosine deletion in position 905 (c905delC) which causes frameshift and an aberrant C-terminal domain. Our report highlights the fact that subjects affected with eye anomalies and harboring SOX2 mutations are at high risk for gonadotropin deficiency, which has important implications for their clinical management. 相似文献
494.
Xiurong Wu Wan-Ting He Shuye Tian Dan Meng Yuanyue Li Wanze Chen Lisheng Li Lili Tian Chuan-Qi Zhong Felicia Han Jianming Chen Jiahuai Han 《PLoS pathogens》2014,10(4)
Viruses hijack host factors for their high speed protein synthesis, but information about these factors is largely unknown. In searching for genes that are involved in viral replication, we carried out a forward genetic screen for Drosophila mutants that are more resistant or sensitive to Drosophila C virus (DCV) infection-caused death, and found a virus-resistant line in which the expression of pelo gene was deficient. Our mechanistic studies excluded the viral resistance of pelo deficient flies resulting from the known Drosophila anti-viral pathways, and revealed that pelo deficiency limits the high level synthesis of the DCV capsid proteins but has no or very little effect on the expression of some other viral proteins, bulk cellular proteins, and transfected exogenous genes. The restriction of replication of other types of viruses in pelo deficient flies was also observed, suggesting pelo is required for high level production of capsids of all kinds of viruses. We show that both pelo deficiency and high level DCV protein synthesis increase aberrant 80S ribosomes, and propose that the preferential requirement of pelo for high level synthesis of viral capsids is at least partly due to the role of pelo in dissociation of stalled 80S ribosomes and clearance of aberrant viral RNA and proteins. Our data demonstrated that pelo is a host factor that is required for high efficiency translation of viral capsids and targeting pelo could be a strategy for general inhibition of viral infection. 相似文献
495.
Life History and Demographic Drivers of Reservoir Competence for Three Tick-Borne Zoonotic Pathogens
Richard S. Ostfeld Taal Levi Anna E. Jolles Lynn B. Martin Parviez R. Hosseini Felicia Keesing 《PloS one》2014,9(9)
Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management. 相似文献
496.
497.
498.
Martin Lundsgaard Hansen Eva Fallentin Carsten Lauridsen Ian Law Birgitte Federspiel Lene B?ksgaard Lars Bo Svendsen Michael Bachmann Nielsen 《PloS one》2014,9(5)
Objectives
To evaluate whether early reductions in CT perfusion parameters predict response to pre-operative chemotherapy prior to surgery for gastroesophageal junction (GEJ) and gastric cancer.Materials and Methods
Twenty-eight patients with adenocarcinoma of the gastro-esophageal junction (GEJ) and stomach were included. Patients received three series of chemotherapy before surgery, each consisting of a 3-week cycle of intravenous epirubicin, cisplatin or oxaliplatin, concomitant with capecitabine peroral. The patients were evaluated with a CT perfusion scan prior to, after the first series of, and after three series of chemotherapy. The CT perfusion scans were performed using a 320-detector row scanner. Tumour volume and perfusion parameters (arterial flow, blood volume and permeability) were computed on a dedicated workstation with a consensus between two radiologists. Response to chemotherapy was evaluated by two measures. Clinical response was defined as a tumour size reduction of more than 50%. Histological response was evaluated based on residual tumour cells in the surgical specimen using the standardized Mandard Score 1 to 5, in which values of 1 and 2 were classified as responders, and 3 to 5 were classified as nonresponders.Results
A decrease in tumour permeability after one series of chemotherapy was positively correlated with clinical response after three series of chemotherapy. Significant changes in permeability and tumour volume were apparent after three series of chemotherapy in both clinical and histological responders. A cut-off value of more than 25% reduction in tumour permeability yielded a sensitivity of 69% and a specificity of 58% for predicting clinical response.Conclusion
Early decrease in permeability is correlated with the likelihood of clinical response to pre-operative chemotherapy in GEJ and gastric cancer. As a single diagnostic test, CT Perfusion only has moderate sensitivity and specificity in response assessment of pre-operative chemotherapy making it insufficient for clinical decision purposes. 相似文献499.
Thomas C. Ings José M. Montoya Jordi Bascompte Nico Blüthgen Lee Brown Carsten F. Dormann François Edwards David Figueroa Ute Jacob J. Iwan Jones Rasmus B. Lauridsen Mark E. Ledger Hannah M. Lewis Jens M. Olesen F.J. Frank van Veen Phil H. Warren Guy Woodward 《The Journal of animal ecology》2009,78(1):253-269
500.
Phosphorylation of Jak2 on Ser(523) inhibits Jak2-dependent leptin receptor signaling 总被引:1,自引:0,他引:1 下载免费PDF全文
Ishida-Takahashi R Rosario F Gong Y Kopp K Stancheva Z Chen X Feener EP Myers MG 《Molecular and cellular biology》2006,26(11):4063-4073
The leptin receptor, LRb, and other cytokine receptors are devoid of intrinsic enzymatic activity and rely upon the activity of constitutively associated Jak family tyrosine kinases to mediate intracellular signaling. In order to clarify mechanisms by which Jak2, the cognate LRb-associated Jak kinase, is regulated and mediates downstream signaling, we employed tandem mass spectroscopic analysis to identify phosphorylation sites on Jak2. We identified Ser523 as the first-described site of Jak2 serine phosphorylation and demonstrated that this site is phosphorylated on Jak2 from intact cells and mouse spleen. Ser523 was highly phosphorylated in HEK293 cells independently of LRb-Jak2 activation, suggesting a potential role for the phosphorylation of Ser523 in the regulation of LRb by other pathways. Indeed, mutation of Ser523 sensitized and prolonged signaling by Jak2 following activation by the intracellular domain of LRb. The effect of Ser523 on Jak2 function was independent of Tyr570-mediated inhibition. Thus, the phosphorylation of Jak2 on Ser523 inhibits Jak2 activity and represents a novel mechanism for the regulation of Jak2-dependent cytokine signaling. 相似文献