全文获取类型
收费全文 | 206篇 |
免费 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 15篇 |
2012年 | 12篇 |
2011年 | 9篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 27篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 4篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有231条查询结果,搜索用时 187 毫秒
31.
Damodar M. Shenoy K. B. Sujith Mangesh U. Gauns Shrikant Patil Amit Sarkar Hema Naik P. V. Narvekar S. W. A. Naqvi 《Biogeochemistry》2012,110(1-3):47-55
Subsurface waters over the western Indian continental shelf experience seasonal anoxia towards the end of the southwest monsoon season. During a 3-day study carried out at the Candolim time series site (off the coast of Goa), dimethylsulphide (DMS) concentrations showed a 40-fold increase to a maximum of 442?nM at 25?m depth compared to the oxygenated surface waters. This extremely high DMS was found to be associated with relatively low chlorophyll a, low phytoplankton cell counts and a high concentration of hydrogen sulphide. However, total dimethylsulphoniopropionate, total dimethylsulphoxide and methanethiol concentrations were quite low and unlikely to account for the DMS build-up through presently known pathways of DMS production. While there are several possible mechanisms for the observed accumulation of DMS, we were unable to pinpoint the exact pathway of DMS production. Future work will involve investigation of the source of DMS through sediment slurry experiments, to explore this interesting link between the carbon and sulphur cycles under anoxic conditions. 相似文献
32.
Background
Bile acids (BAs) regulate cardiovascular function via diverse mechanisms. Although in both health and disease serum glycine-conjugated BAs are more abundant than taurine-conjugated BAs, their effects on myogenic tone (MT), a key determinant of systemic vascular resistance (SVR), have not been examined.Methodology/Principal Findings
Fourth-order mesenteric arteries (170–250 µm) isolated from Sprague-Dawley rats were pressurized at 70 mmHg and allowed to develop spontaneous constriction, i.e., MT. Deoxycholylglycine (DCG; 0.1–100 µM), a glycine-conjugated major secondary BA, induced reversible, concentration-dependent reduction of MT that was similar in endothelium-intact and -denuded arteries. DCG reduced the myogenic response to stepwise increase in pressure (20 to 100 mmHg). Neither atropine nor the combination of L-NAME (a NOS inhibitor) plus indomethacin altered DCG-mediated reduction of MT. K+ channel blockade with glibenclamide (KATP), 4-aminopyradine (KV), BaCl2 (KIR) or tetraethylammonium (TEA, KCa) were also ineffective. In Fluo-2-loaded arteries, DCG markedly reduced vascular smooth muscle cell (VSM) Ca2+ fluorescence (∼50%). In arteries incubated with DCG, physiological salt solution (PSS) with high Ca2+ (4 mM) restored myogenic response. DCG reduced vascular tone and VSM cytoplasmic Ca2+ responses (∼50%) of phenylephrine (PE)- and Ang II-treated arteries, but did not affect KCl-induced vasoconstriction.Conclusion
In rat mesenteric resistance arteries DCG reduces pressure- and agonist-induced vasoconstriction and VSM cytoplasmic Ca2+ responses, independent of muscarinic receptor, NO or K+ channel activation. We conclude that BAs alter vasomotor responses, an effect favoring reduced SVR. These findings are likely pertinent to vascular dysfunction in cirrhosis and other conditions associated with elevated serum BAs. 相似文献33.
34.
35.
36.
Recent studies have suggested that antithrombin (AT) could act as a significant physiologic regulator of FVIIa. However, in vitro studies showed that AT could inhibit FVIIa effectively only when it was bound to tissue factor (TF). Circulating blood is known to contain only traces of TF, at best. FVIIa also binds endothelial cell protein C receptor (EPCR), but the role of EPCR on FVIIa inactivation by AT is unknown. The present study was designed to investigate the role of TF and EPCR in inactivation of FVIIa by AT in vivo. Low human TF mice (low TF, ∼1% expression of the mouse TF level) and high human TF mice (HTF, ∼100% of the mouse TF level) were injected with human rFVIIa (120 µg kg−1 body weight) via the tail vein. At varying time intervals following rFVIIa administration, blood was collected to measure FVIIa-AT complex and rFVIIa antigen levels in the plasma. Despite the large difference in TF expression in the mice, HTF mice generated only 40–50% more of FVIIa-AT complex as compared to low TF mice. Increasing the concentration of TF in vivo in HTF mice by LPS injection increased the levels of FVIIa-AT complexes by about 25%. No significant differences were found in FVIIa-AT levels among wild-type, EPCR-deficient, and EPCR-overexpressing mice. The levels of FVIIa-AT complex formed in vitro and ex vivo were much lower than that was found in vivo. In summary, our results suggest that traces of TF that may be present in circulating blood or extravascular TF that is transiently exposed during normal vessel damage contributes to inactivation of FVIIa by AT in circulation. However, TF’s role in AT inactivation of FVIIa appears to be minor and other factor(s) present in plasma, on blood cells or vascular endothelium may play a predominant role in this process. 相似文献
37.
Sarita Pandey Anurag Kirti Arvind Kumar Hema Rajaram 《Functional & integrative genomics》2018,18(4):357-367
The ubiquitous SbcCD exonuclease complex has been shown to perform an important role in DNA repair across prokaryotes and eukaryotes. However, they have remained uncharacterized in the ancient and stress-tolerant cyanobacteria. In the cyanobacterium Anabaena sp. strain PCC7120, SbcC and SbcD homologs, defined on the basis of the presence of corresponding functional domains, are annotated as hypothetical proteins, namely Alr3988 and All4463 respectively. Unlike the presence of sbcC and sbcD genes in a bicistronic operon in most organisms, these genes were distantly placed on the chromosome in Anabaena, and found to be negatively regulated by LexA. Both the genes were found to be essential in Anabaena as the individual deletion mutants were non-viable. On the other hand, the proteins could be individually overexpressed in Anabaena with no effect on normal cell physiology. However, they contributed positively to enhance the tolerance to different DNA damage-inducing stresses, such as mitomycin C and UV- and γ-radiation. This indicated that the two proteins, at least when overexpressed, could function independently and mitigate the damage caused due to the formation of DNA adducts and single- and double-strand breaks in Anabaena. This is the first report on possible independent in vivo functioning of SbcC and SbcD homologs in any bacteria, and the first effort to functionally characterize the proteins in any cyanobacteria. 相似文献
38.
39.
Four Plasmodium species cause malaria in humans: Plasmodium vivax is the most widespread and results in pronounced morbidity. India (population >1 billion) is a major contributor to the burden of vivax malaria. With a resurgence in interest concerning the neglected burden of vivax malaria and the completion of the P. vivax genome, it is timely to review what is known concerning P. vivax in India. The P. vivax population is highly diverse in terms of relapse patterns, drug response and clinical profiles, and highly genetically variable according to studies of antigen genes, isoenzyme markers and microsatellites. The unique epidemiology of malaria in India, where P. vivax predominates over Plasmodium falciparum, renders this location ideal for studying the dynamics of co-infection. 相似文献
40.