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   134篇
  免费   13篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   2篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   5篇
  2012年   6篇
  2011年   15篇
  2010年   8篇
  2009年   7篇
  2008年   3篇
  2007年   6篇
  2006年   2篇
  2005年   3篇
  2004年   2篇
  2003年   2篇
  2001年   2篇
  2000年   3篇
  1999年   8篇
  1998年   3篇
  1996年   3篇
  1995年   2篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   5篇
  1988年   6篇
  1987年   5篇
  1985年   3篇
  1984年   3篇
  1983年   1篇
  1981年   3篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1975年   3篇
  1973年   2篇
  1970年   1篇
  1935年   1篇
排序方式: 共有147条查询结果,搜索用时 203 毫秒
71.

Key message

Coordinated association and linkage mapping identified 25 grain quality QTLs in multiple environments, and fine mapping of the Wx locus supports the use of high-density genetic markers in linkage mapping.

Abstract

There is a wide range of end-use products made from cereal grains, and these products often demand different grain characteristics. Fortunately, cereal crop species including sorghum [Sorghum bicolor (L.) Moench] contain high phenotypic variation for traits influencing grain quality. Identifying genetic variants underlying this phenotypic variation allows plant breeders to develop genotypes with grain attributes optimized for their intended usage. Multiple sorghum mapping populations were rigorously phenotyped across two environments (SC Coastal Plain and Central TX) in 2 years for five major grain quality traits: amylose, starch, crude protein, crude fat, and gross energy. Coordinated association and linkage mapping revealed several robust QTLs that make prime targets to improve grain quality for food, feed, and fuel products. Although the amylose QTL interval spanned many megabases, the marker with greatest significance was located just 12 kb from waxy (Wx), the primary gene regulating amylose production in cereal grains. This suggests higher resolution mapping in recombinant inbred line (RIL) populations can be obtained when genotyped at a high marker density. The major QTL for crude fat content, identified in both a RIL population and grain sorghum diversity panel, encompassed the DGAT1 locus, a critical gene involved in maize lipid biosynthesis. Another QTL on chromosome 1 was consistently mapped in both RIL populations for multiple grain quality traits including starch, crude protein, and gross energy. Collectively, these genetic regions offer excellent opportunities to manipulate grain composition and set up future studies for gene validation.
  相似文献   
72.
The compounds (eta5-C5H5)2TiCl2 (I), currently undergoing phase II trials, (eta5-C5H5)(eta5-C5H4CO2Me)TiCl2 (II) and C5H4CO2Me)2TiCl2 (III) are assessed for their efficacies against a small lung cancer cell line. It is found that the introduction of the electron withdrawing carbomethoxy group into the cyclopentadienyl rings increases the effectiveness of this class of drugs, such that III compares favorably with the well known cisplatin.  相似文献   
73.
(1) We measured the thermal conductance of dorsal pelage from meadow voles (Microtus pennsylvanicus) and white-footed mice (Peromyscus leucopus) during summer and winter.

(2) Thermal conductance was lower in the winter pelage of both species, but the seasonal change was greater in meadow voles.

(3) The form of wind speed dependence was determined by fitting a nonlinear curve of the form a+buc to data recorded at five wind speeds. The most appropriate exponent c was between 0.908 and 0.987, depending on species and season. These values are common and suggest that thermal and dynamic forces are important.

Keywords: Heat loss; Insulation; Meadow voles; Pelage; Rodentia; Thermoregulation; White-footed mice  相似文献   

74.

Background  

In V. cholerae, the biogenesis of capsule polysaccharide is poorly understood. The elucidation of capsule structure and biogenesis is critical to understanding the evolution of surface polysaccharide and the internal relationship between the capsule and LPS in this species. V. cholerae serogroup O31 NRT36S, a human pathogen that produces a heat-stable enterotoxin (NAG-ST), is encapsulated. Here, we report the covalent structure and studies of the biogenesis of the capsule in V. cholerae NRT36S.  相似文献   
75.
Andrew JG Simpson 《Genome biology》2000,1(1):reports411.1-reports4112
A meeting report of the sessions on human, eukaryotic and bacterial genome sequencing at the American Society for Microbiology and Institut Pasteur joint conference: Genomes 2000 International Conference on Microbial and Model Genomes, Paris, April 11-15, 2000  相似文献   
76.
77.
Many studies have shown that endotherms become more heterothermic when the costs of thermoregulation are high and/or when limited energy availability constrains thermoregulatory capacity. However, the roles of many ecological variables, including constraints on foraging opportunities and/or success, remain largely unknown. To test the prediction that thermoregulatory patterns should be related to foraging opportunities in a heterothermic endotherm, we examined the relationship between the lunar cycle and heterothermy in Freckled Nightjars (Caprimulgus tristigma), which are visually orienting, nocturnal insectivores that are dependent on ambient light to forage. This model system provides an opportunity to assess whether variation in foraging opportunities influences the expression of heterothermy. The nightjars were active and foraged for insects when moonlight was available but became inactive and heterothermic in the absence of moonlight. Lunar illumination was a much stronger predictor of the magnitude of heterothermic responses than was air temperature (T(a)). Our data suggest that heterothermy was strongly related to variation in foraging opportunities associated with the lunar cycle, even though food abundance appeared to remain relatively high throughout the study period. Patterns of thermoregulation in this population of Freckled Nightjars provide novel insights into the environmental and ecological determinants of heterothermy, with the lunar cycle, and not T(a), being the strongest predictor of torpor use.  相似文献   
78.
The design of drugs with selective tissue distribution can be an effective strategy for enhancing efficacy and safety, but understanding the translation of preclinical tissue distribution data to the clinic remains an important challenge. As part of a discovery program to identify next generation liver selective HMG-CoA reductase inhibitors we report the identification of (3R,5R)-7-(4-((3-fluorobenzyl)carbamoyl)-5-cyclopropyl-2-(4-fluorophenyl)-1H-imidazol-1-yl)-3,5-dihydroxyheptanoic acid (26) as a candidate for treating hypercholesterlemia. Clinical evaluation of 26 (PF-03491165), as well as the previously reported 2 (PF-03052334), provided an opportunity for a case study comparison of the preclinical and clinical pharmacokinetics as well as pharmacodynamics of tissue targeted HMG-CoA reductase inhibitors.  相似文献   
79.

Background

Low environmental air quality is a significant cause of mortality and morbidity and this question is now emerging as a main concern of governmental authorities. Airborne pollution results from the combination of chemicals, fine particles, and micro-organisms quantitatively or qualitatively dangerous for health or for the environment. Increasing regulations and limitations for outdoor air quality have been decreed in regards to chemicals and particles contrary to micro-organisms. Indeed, pertinent and reliable tests to evaluate this biohazard are scarce. In this work, our purpose was to evaluate the Caenorhaditis elegans killing test, a model considered as an equivalent to the mouse acute toxicity test in pharmaceutical industry, in order to monitor air bacterial quality.

Findings

The present study investigates the bacterial population in dust clouds generated during crop ship loading in harbor installations (Rouen harbor, Normandy, France). With a biocollector, airborne bacteria were impacted onto the surface of agar medium. After incubation, a replicate of the colonies on a fresh agar medium was done using a velvet. All the replicated colonies were pooled creating the "Total Air Sample". Meanwhile, all the colonies on the original plate were isolated. Among which, five representative bacterial strains were chosen. The virulence of these representatives was compared to that of the "Total Air Sample" using the Caenorhaditis elegans killing test. The survival kinetic of nematodes fed with the "Total Air Sample" is consistent with the kinetics obtained using the five different representatives strains.

Conclusions

Bacterial air quality can now be monitored in a one shot test using the Caenorhaditis elegans killing test.
  相似文献   
80.

Background  

Most dental implant systems are presently made of two pieces: the implant itself and the abutment. The connection tightness between those two pieces is a key point to prevent bacterial proliferation, tissue inflammation and bone loss. The leak has been previously estimated by microbial, color tracer and endotoxin percolation.  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