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   70篇
  免费   2篇
  2021年   1篇
  2020年   2篇
  2018年   1篇
  2017年   2篇
  2015年   1篇
  2014年   8篇
  2013年   8篇
  2012年   4篇
  2011年   4篇
  2010年   3篇
  2009年   7篇
  2008年   5篇
  2007年   6篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  1999年   1篇
  1998年   3篇
  1995年   1篇
  1989年   1篇
  1988年   4篇
  1987年   1篇
  1986年   2篇
排序方式: 共有72条查询结果,搜索用时 500 毫秒
51.
52.
53.
54.
55.
56.
Sesame (Sesamum indicum L.) is an important staple crop of the family Pedaliaceae. The commercial production of sesame is still dependent on the applications of chemical fertilizers. Mycorrhiza inoculum resulted in better morphological and biochemical traits in vegetables. Thus, here the outcome of arbuscular mycorrhizal fungi (AMF) and Pseudomonas fluorescence (ATCC-17400) inoculation was studied in the pot culture experiment. Primarily, there seems to be a promising opportunity of AMF in sesame under pot and field trials because of enhanced morphological parameters, especially root weight, and disparities in nutrients and metabolites. The AMF appears to be an option to boost plant growth, mineral content, and sesame yield. The AMF treatment with Pseudomonas fluorescence strain (ATCC-17400) determined the maximum values for the morphological traits and mineral content. Overall, our study highlights mycorrhizal fungi and other microbes efficacy in achieving a successful sesame production.  相似文献   
57.

Background

Leisure time physical activity reduces the risk of premature mortality, but the years of life expectancy gained at different levels remains unclear. Our objective was to determine the years of life gained after age 40 associated with various levels of physical activity, both overall and according to body mass index (BMI) groups, in a large pooled analysis.

Methods and Findings

We examined the association of leisure time physical activity with mortality during follow-up in pooled data from six prospective cohort studies in the National Cancer Institute Cohort Consortium, comprising 654,827 individuals, 21–90 y of age. Physical activity was categorized by metabolic equivalent hours per week (MET-h/wk). Life expectancies and years of life gained/lost were calculated using direct adjusted survival curves (for participants 40+ years of age), with 95% confidence intervals (CIs) derived by bootstrap. The study includes a median 10 y of follow-up and 82,465 deaths. A physical activity level of 0.1–3.74 MET-h/wk, equivalent to brisk walking for up to 75 min/wk, was associated with a gain of 1.8 (95% CI: 1.6–2.0) y in life expectancy relative to no leisure time activity (0 MET-h/wk). Higher levels of physical activity were associated with greater gains in life expectancy, with a gain of 4.5 (95% CI: 4.3–4.7) y at the highest level (22.5+ MET-h/wk, equivalent to brisk walking for 450+ min/wk). Substantial gains were also observed in each BMI group. In joint analyses, being active (7.5+ MET-h/wk) and normal weight (BMI 18.5–24.9) was associated with a gain of 7.2 (95% CI: 6.5–7.9) y of life compared to being inactive (0 MET-h/wk) and obese (BMI 35.0+). A limitation was that physical activity and BMI were ascertained by self report.

Conclusions

More leisure time physical activity was associated with longer life expectancy across a range of activity levels and BMI groups. Please see later in the article for the Editors'' Summary  相似文献   
58.
59.
The nurse shark, Ginglymostoma cirratum, is an obligate suction feeder that preys on benthic invertebrates and fish. Its cranial morphology exhibits a suite of structural and functional modifications that facilitate this mode of prey capture. During suction‐feeding, subambient pressure is generated by the ventral expansion of the hyoid apparatus and the floor of its buccopharyngeal cavity. As in suction‐feeding bony fishes, the nurse shark exhibits expansive, compressive, and recovery kinematic phases that produce posterior‐directed water flow through the buccopharyngeal cavity. However, there is generally neither a preparatory phase nor cranial elevation. Suction is generated by the rapid depression of the buccopharyngeal floor by the coracoarcualis, coracohyoideus, and coracobranchiales muscles. Because the hyoid arch of G. cirratum is loosely connected to the mandible, contraction of the rectus cervicis muscle group can greatly depress the floor of the buccopharyngeal cavity below the depressed mandible, resulting in large volumetric expansion. Suction pressures in the nurse shark vary greatly, but include the greatest subambient pressures reported for an aquatic‐feeding vertebrate. Maximum suction pressure does not appear to be related to shark size, but is correlated with the rate of buccopharyngeal expansion. As in suction‐feeding bony fishes, suction in the nurse shark is only effective within approximately 3 cm in front of the mouth. The foraging behavior of this shark is most likely constrained to ambushing or stalking due to the exponential decay of effective suction in front of the mouth. Prey capture may be facilitated by foraging within reef confines and close to the substrate, which can enhance the effective suction distance, or by foraging at night when it can more closely approach prey. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.  相似文献   
60.
This article explores why in India's Jharkhand, Mundas, often depicted as poor tribals, participate in elections to keep the state away, seeing it as foreign, dangerous, and juxtaposing its self-interested and divisive politics with a sacral polity, the parha . Munda disengagement with the state results from a complex combination of their contrasting the state with the sacral polity, historical experience of exploitation by state officers, and social relations with rural elites who, seeking to maintain dominance, reproduce Munda imaginings. The article thus draws attention to multiple co-existing notions of politics and the importance of a local political economy in the social production of cultural imaginings of the state.  相似文献   
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