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   614篇
  免费   47篇
  2023年   3篇
  2021年   10篇
  2020年   5篇
  2019年   6篇
  2018年   10篇
  2017年   10篇
  2016年   12篇
  2015年   34篇
  2014年   31篇
  2013年   33篇
  2012年   46篇
  2011年   40篇
  2010年   32篇
  2009年   35篇
  2008年   41篇
  2007年   30篇
  2006年   30篇
  2005年   22篇
  2004年   27篇
  2003年   25篇
  2002年   26篇
  2001年   6篇
  1999年   9篇
  1998年   5篇
  1997年   5篇
  1996年   4篇
  1995年   6篇
  1994年   4篇
  1993年   6篇
  1992年   4篇
  1991年   6篇
  1990年   6篇
  1989年   3篇
  1988年   7篇
  1985年   3篇
  1984年   3篇
  1983年   4篇
  1982年   3篇
  1980年   9篇
  1979年   4篇
  1978年   5篇
  1975年   5篇
  1973年   5篇
  1972年   4篇
  1971年   6篇
  1970年   3篇
  1968年   4篇
  1967年   5篇
  1966年   5篇
  1965年   3篇
排序方式: 共有661条查询结果,搜索用时 500 毫秒
1.
2.
The aim of the study was to investigate the possibility of a seasonal variation in reactivity to apples in 27 birch pollen allergic patients. Before and during the birch pollen season 1998, the patients were subjected to double-blind, placebo-controlled food challenges (DBPCFCs) with grated fresh Golden Delicious apple followed by an open food challenge with whole fresh apple. The clinical reactions elicited during the challenges were evaluated both by the patients and the investigators. Moreover, the skin reactivity and the in vitro reactivity to apple were evaluated by skin prick test (SPT), leukocyte histamine release (HR), measurement of specific IgE, and immunoblotting experiments. The sensitivity of the DBPCFC, when compared with the result of the open challenge, was 0.74 (14/19) before the season and 0.80 (16/20) during the season. None of the patients reacted to the blinded challenge without a subsequent reaction to the open challenge. One placebo reaction was registered both before and in season, but not in the same patient. The patient scores of the first positive challenges, and the maximal scores of each combined blinded and open challenge session, were significantly increased during the pollen season (P<0.05). The scores of the open challenge were significantly higher than the scores of the DBPCFC both before the season and during the in-season challenges (P<0.05). Specific IgE against Golden Delicious increased during season (P<0.05), while neither SPT, HR, nor immunoblotting experiments could confirm an increase in reactivity. In conclusion, the results of the oral challenge tests indicated an increase in clinical reactivity to apples during the birch pollen season in birch pollen allergic individuals.  相似文献   
3.
4.
5.
6.
Helle  K. B.  Miralto  A.  Pihl  K. E.  Tota  B. 《Cell and tissue research》1983,231(2):399-414
Summary The general and ultrastructural organization of the heart of the elasmobranch, Scyllium stellare, was studied in normal and in anoxic animals. The rich coronary supply was revealed three-dimensionally by the use of corrosion casts, showing a thebesian system of coronary arterioles and capillaries in the thin, outer compact layer as well as in the predominant, inner spongy layer of trabeculae.Only the sinus venosus received a neuronal input of large bundles of granule-containing axons terminating at fenestrated regions of the endocardium and suggesting a neurohormonal function.A simple, tubular sarcoplasmic reticulum with flattened junctional cisternae was present in myocardial cells of 1–5 m diameter, which contained one or two bundles of myofibrils. The latter were closely apposed to the inner aspect of the plasmalemma. Mitochondria were located centrally in the cells, which were joined by unfolded desmosomes involving Z-band material.Long periods of anoxia were tolerated without loss of heart function, but at the expense of cytoplasmic glycogen. Lipid granules were abundant in all layers and chambers, notably in animals prepared in the summer. The lipid granules displayed a marked increase in electron density when the heart was incubated in a buffered oxalate solution prior to fixation. A glycogen-sparing effect of the lipids during anoxia was observed.  相似文献   
7.
1. Chromogranin A has been isolated from the washed membrane fraction of highly purified chromaffin granules after solubilization in Triton X-100. A hydrated molecular weight of 2.9·105 has been obtained for chromogranin AM which in its electrophoretic mobility and molecular volume appears very similar to chromogranin AI of the water-soluble fraction.  相似文献   
8.
The susceptibility to Tedion of haploid and diploid-haploid mixtures of eggs of Tetranychus urticae Koch was examined. It was concluded for a normal susceptible strain that haploid eggs are more susceptible to Tedion than diploid eggs. This difference in tolerance between haploid and diploid eggs could not be established for a strain resistant to Tedion.Mass crosses between the susceptible and the resistant strain were made. Susceptible females, mated by resistant males, produce susceptible haploid and resistant diploid offspring. Resistant females, mated by susceptible males, gave a resistant offspring. Both sexes can also transmit resistance to Tedion. As there was a difference in tolerance between diploid offspring in the reciprocal crosses, it is assumed that either a maternal or a cytoplasmic component is also present in the genetical mechanism of Tedion-resistance.
Zusammenfassung Es wurde die Empfindlichkeit haploider und diploid-haploider Gemische von Eiern von Tetranychus urticae Koch gegenüber Tedion untersucht. Für einen normal empfindlichen Stamm wurde aus toxikologischen Daten und einer Verschiebung des Geschlechterverhältnisses erschlossen, daß haploide Eier gegenüber Tedion empfindlicher sind als diploide. Dieser Toleranzunterschied zwischen haploiden und diploiden Nachkommen konnte bei einem gegen Tedion resistenten Stamm nicht nachgewiesen werden.Es wurden Massenkreuzungen zwischen empfindlichen und resistenten Stämmen durch-geführt. Empfindliche Weibchen, mit resistenten Männchen gepaart, produzierten empfindliche haploide und resistente diploide Nachkommen. Resistente Weibchen, mit empfindlichen Männchen gepaart, ergaben eine resistente Nachkommenschaft. Beide Geschlechter können also die Resistenz gegen Tedion übertragen. Da bei den reziproken Kreuzungen ein Toleranzunterschied zwischen den diploiden Nachkommen auftritt, wird angenommen, daß in dem genetischen Mechanismus der Tedion-Resistenz auch eine mütterliche oder eine zytoplasmatische Komponente vorhanden ist.
  相似文献   
9.
An albino male was discovered in a population of Tetranychus pacificus, as a result of spontaneous mutation. It appeared that this albinism was recessive and under monogenic control. A maternal effect was demonstrated. The albinism is a suitable marker for all stages of development in this mite species.
Albinismus als genetische markierung bei tetranychus pacificus
Zusammenfassung In einer Population von Tetranychus pacificus wurde als Ergebnis spontaner Mutation ein albinotisches Männchen entdeckt. Es wird erwiesen dass dieser Albinismus rezessiv und monogenetisch beding ist. Ein mütterlicher Effekt war nachzuweisen. Der Albinismus ist eine geeignete genetische Markierung für alle Entwicklungsstadien bei dieser Spinnmilben-Art.
  相似文献   
10.
The release of protein from the stimulated adrenal medulla.   总被引:8,自引:0,他引:8       下载免费PDF全文
  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