首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   945篇
  免费   57篇
  国内免费   3篇
  1005篇
  2023年   3篇
  2022年   11篇
  2021年   27篇
  2020年   20篇
  2019年   28篇
  2018年   20篇
  2017年   27篇
  2016年   40篇
  2015年   46篇
  2014年   57篇
  2013年   69篇
  2012年   83篇
  2011年   76篇
  2010年   52篇
  2009年   52篇
  2008年   61篇
  2007年   63篇
  2006年   37篇
  2005年   41篇
  2004年   36篇
  2003年   28篇
  2002年   32篇
  2001年   10篇
  2000年   6篇
  1999年   10篇
  1998年   4篇
  1997年   2篇
  1996年   9篇
  1995年   5篇
  1994年   3篇
  1993年   3篇
  1992年   5篇
  1991年   4篇
  1990年   4篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1973年   2篇
  1972年   1篇
  1970年   1篇
  1964年   1篇
排序方式: 共有1005条查询结果,搜索用时 15 毫秒
141.

Background

To determine correlation of multiple parameters of socioeconomic status with cardiovascular risk factors in India.

Methods

The study was performed at eleven cities using cluster sampling. Subjects (n = 6198, men 3426, women 2772) were evaluated for socioeconomic, demographic, biophysical and biochemical factors. They were classified into low, medium and high socioeconomic groups based on educational level (<10, 10–15 and >15 yr formal education), occupational class and socioeconomic scale. Risk factor differences were evaluated using multivariate logistic regression.

Results

Age-adjusted prevalence (%) of risk factors in men and women was overweight or obesity in 41.1 and 45.2, obesity 8.3 and 15.8, high waist circumference 35.7 and 57.5, high waist-hip ratio 69.0 and 83.8, hypertension 32.5 and 30.4, hypercholesterolemia 24.8 and 25.3, low HDL cholesterol 34.1 and 35.1, high triglycerides 41.2 and 31.5, diabetes 16.7 and 14.4 and metabolic syndrome in 32.2 and 40.4 percent. Lifestyle factors were smoking 12.0 and 0.5, other tobacco use 12.7 and 6.3, high fat intake 51.2 and 48.2, low fruits/vegetables intake 25.3 and 28.9, and physical inactivity in 38.8 and 46.1%. Prevalence of > = 3 risk factors was significantly greater in low (28.0%) vs. middle (23.9%) or high (22.1%) educational groups (p<0.01). In low vs. high educational groups there was greater prevalence of high waist-hip ratio (odds ratio 2.18, confidence interval 1.65–2.71), low HDL cholesterol (1.51, 1.27–1.80), hypertriglyceridemia (1.16, 0.99–1.37), smoking/tobacco use (3.27, 2.66–4.01), and low physical activity (1.15, 0.97–1.37); and lower prevalence of high fat diet (0.47, 0.38–0.57),overweight/obesity (0.68, 0.58–0.80) and hypercholesterolemia (0.79, 0.66–0.94). Similar associations were observed with occupational and socioeconomic status.

Conclusions

Low educational, occupational and socioeconomic status Asian Indians have greater prevalence of truncal obesity, low HDL cholesterol, hypertriglyceridemia, smoking or tobacco use and low physical activity and clustering of > = 3 major cardiovascular risk factors.  相似文献   
142.

Background

The Indian golden saturniid silkmoth (Antheraea assama), popularly known as muga silkmoth, is a semi-domesticated silk producing insect confined to a narrow habitat range of the northeastern region of India. Owing to the prevailing socio-political problems, the muga silkworm habitats in the northeastern region have not been accessible hampering the phylogeography studies of this rare silkmoth. Recently, we have been successful in our attempt to collect muga cocoon samples, although to a limited extent, from their natural habitats. Out of 87 microsatellite markers developed previously for A. assama, 13 informative markers were employed to genotype 97 individuals from six populations and analyzed their population structure and genetic variation.

Methodology/Principal Findings

We observed highly significant genetic diversity in one of the populations (WWS-1, a population derived from West Garo Hills region of Meghalaya state). Further analysis with and without WWS-1 population revealed that dramatic genetic differentiation (global FST = 0.301) was due to high genetic diversity contributed by WWS-1 population. Analysis of the remaining five populations (excluding WWS-1) showed a marked reduction in the number of alleles at all the employed loci. Structure analysis showed the presence of only two clusters: one formed by WWS-1 population and the other included the remaining five populations, inferring that there is no significant genetic diversity within and between these five populations, and suggesting that these five populations are probably derived from a single population. Patterns of recent population bottlenecks were not evident in any of the six populations studied.

Conclusions/Significance

A. assama inhabiting the WWS-1 region revealed very high genetic diversity, and was genetically divergent from the five populations studied. The efforts should be continued to identify and study such populations from this region as well as other muga silkworm habitats. The information generated will be very useful in conservation of dwindling muga culture in Northeast India.  相似文献   
143.
144.
Medicinal plants are extensively utilized in traditional and herbal medicines, both in India and around the world due to the presence of diverse low molecular weight natural products such as flavonoids, alkaloids, terpenoids and sterols. Flavonoids which have health benefits for humans are the large class of phenylpropanoid-derived secondary metabolites and are mostly glycosylated by UDP-glycosyltransferases (UGTs). Although large numbers of different UGTs are known from higher plants, very few protein structures have been reported till now. In the present study, the three-dimensional model of flavonoid specific glycosyltransferases (WsFGT) from Withania somnifera was constructed based on the crystal structure of plant UGTs. The resulted model was assessed by various tools and the final refined model revealed GT-B type fold. Further, to understand the sugar donors and acceptors interactions with the active site of WsFGT, docking studies were performed. The amino acids from conserved PSPG box were interacted with sugar donor while His18, Asp110, Trp352 and Asn353 were important for catalytic function. This structural and docking information will be useful to understand the glycosylation mechanism of flavonoid glucosides.

Abbreviations

DOPE - Discrete Optimized Potential Energy, PDB - Protein Data Bank, PSPG - Plant Secondary Product Glycosyltransferase, RMSD - Root Mean Squared Deviation, UDP - Uridine diphosphate, UGT - UDP-glycosyltransferases.  相似文献   
145.
146.
147.
This report examines an unusual case of Srongyloides stercoralis hyperinfection in a 63-yr-old man. The patient had a history of vitamin B deficiency, on and off diarrhea, and clinical pellagra for a decade and a half. There was also evidence of extreme eosinophilia. The patient did not have any associated illness suggestive of immunosuppression. Treatment with ivermectin resulted in remarkable clinical improvement and reversion of eosinophil count to normal.  相似文献   
148.
Old World cutaneous leishmaniasis is caused by infection with Leishmania major and Leishmania tropica. Pentamidine and related dications exhibit broad spectrum antiprotozoal activity. Based on the previously reported efficacy of these compounds against related organisms, 18 structural analogs of pentamidine were evaluated for in vitro antileishmanial activity, using pentamidine as the standard reference drug for comparison. Furan analogs and reversed amidine compounds were examined for activity against L. major and L. tropica promastigotes. The most active compounds against both Leishmania species were in the reversed amidine series. DB745 and DB746 exhibited the highest activity against L. major and DB745 was the most active compound against L. tropica. Both of these compounds exhibited 50% inhibitory concentrations (IC50) below 1 nM for L. major. Ten reversed amidines were also tested for their ability to inhibit growth in an axenic amastigote model. Nine of 10 reversed amidine analogs were active at concentrations below 1 nM. These results justify further study of dicationic compounds as potential new agents for treating cutaneous leishmaniasis.  相似文献   
149.
Top-down control analysis (TDCA) is a useful tool for quantifying constraints on metabolic pathways that might be overcome by biotechnological approaches. Previous studies on lipid accumulation in oilseed rape have suggested that diacylglycerol acyltransferase (DGAT), which catalyses the final step in seed oil biosynthesis, might be an effective target for enhancing seed oil content. Here, increased seed oil content, increased DGAT activity, and reduced substrate:product ratio are demonstrated, as well as reduced flux control by complex lipid assembly, as determined by TDCA in Brassica napus (canola) lines which overexpress the gene encoding type-1 DGAT. Lines overexpressing DGAT1 also exhibited considerably enhanced seed oil content under drought conditions. These results support the use of TDCA in guiding the rational selection of molecular targets for oilseed modification. The most effective lines had a seed oil increase of 14%. Moreover, overexpression of DGAT1 under drought conditions reduced this environmental penalty on seed oil content.  相似文献   
150.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号