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   98篇
  免费   5篇
  国内免费   4篇
  2021年   5篇
  2020年   4篇
  2019年   1篇
  2018年   2篇
  2017年   2篇
  2016年   5篇
  2015年   3篇
  2014年   3篇
  2013年   5篇
  2012年   4篇
  2011年   5篇
  2010年   7篇
  2009年   6篇
  2008年   3篇
  2007年   8篇
  2006年   3篇
  2004年   7篇
  2003年   1篇
  2001年   4篇
  1998年   4篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1993年   2篇
  1990年   1篇
  1987年   1篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1976年   1篇
  1972年   1篇
  1971年   1篇
  1955年   1篇
  1954年   4篇
  1950年   1篇
  1934年   1篇
  1916年   1篇
  1906年   1篇
  1905年   1篇
排序方式: 共有107条查询结果,搜索用时 578 毫秒
1.
This is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape (Brassica napus var. silvestris) cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities. The proportion of infected seeds produced by artificially infected plants of winter oilseed rape (Brassica napus ssp. oleifera) and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus-infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL-507 0.2%, SL-509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seedlings.  相似文献   
2.
Supraorbital bones in Saurolophus angustirostris are described, and their presence in all hadrosaurs is suggested. Frontal-nasal and premaxillar-nasal fontanellae are distinguished in hadrosaurs; their presence is explained as connected with growth and considered to he responsible for the variability of crest structures. New data indicating the presence of a cartilaginous diverticulum nasi within the circumnarial depression in Saurobphus ongustirostris are presented. A physiological (respiratory and/or thermoregulatory) function of the nasal diverticulum is proposed.  相似文献   
3.
Food rewards were given contingent upon the performance of one of three natural responses in adult male pigtail macaques: scratching, yawning, and the facial expression “protruded lips.” Scratching rapidly increased in frequency when it was followed by food, as did variability in form of scratching and one form in particular, using the feet. The facial expression was resistant to the conditioning procedures. Yawning increased in frequency when followed by food, with extinction and reconditioning procedures confirming the establishment of the conditioned response. This is the first report of the conditioning of yawning in primates. Together, the results contribute to the literature on the differential conditionability of different classes of behavior, and suggest the possibility that macaques can voluntarily display “reflexive” acts for social goals.  相似文献   
4.
5.
The paper presents multiplex panels of polymorphic microsatellites for two closely related cryptic species Pipistrellus pipistrellus and Pipistrellus pygmaeus. We tested the cross‐species amplification of 34 microsatellite loci, originally developed for five vespertilionid bat species. Ten and nine polymorphic loci in P. pipistrellus (mean number of alleles per locus = 10.5) and P. pygmaeus (8.1), respectively, in three multiplex polymerase chain reactions per species were amplified. All loci can be analysed in a single fragment analysis and can be used as markers to the study of evolution and the ecology of structured populations of socially living bats.  相似文献   
6.
7.
8.

Background  

Cystic Fibrosis is a pleiotropic disease in humans with primary morbidity and mortality associated with a lung disease phenotype. However, knockout in the mouse of cftr, the gene whose mutant alleles are responsible for cystic fibrosis, has previously failed to produce a readily, quantifiable lung phenotype.  相似文献   
9.
Globozoospermia is a rare (incidence <0.1% in male infertile patients) form of teratozoospermia, mainly characterized by round-headed spermatozoa that lack an acrosome. It originates from a disturbed spermiogenesis, which is expected to be induced by a genetic factor. Several family cases and recessive mouse models with the same phenotype support this expectation. In this study, we present a consanguineous family with three affected brothers, in whom we have identified a homozygous mutation in the spermatogenesis-specific gene SPATA16. This is the first example of a nonsyndromic male infertility condition in humans caused by an autosomal gene defect, and it could also mean that the identification of other partners like SPATA16 could elucidate acrosome formation.  相似文献   
10.
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