不能生育的雌鸽     

J·P·史托斯高夫  刘正光 《环球赛鸽科技》2004,(6)

造成雌鸽不能生育的情况的原因一定是很多的,作者以自己养鸽生涯中的经验,历数种种可能,想必会对你有所启发。这是一个广义的概念,涉及从先天性不育到老年不育的各个方面,包括相对性不育,即雌鸽产蛋少、产蛋不正常(比如无壳蛋),也可能是个别雌鸽不育,出现雏鸽  相似文献   

幼鸽日益消瘦的问题     

J·P·杜夏尔  刘正光 《环球赛鸽科技》2006,(1)

每年春季,比利时各地的鸽友都在抱怨一种疾病,一般称其为鸽腺病毒病。这究竟是种什么疾病呢?有些科研人员把这种疾病规为圆环病毒 (circovirus),一种极少有人知道的病毒。为了使问题更明确一些,我们把这问题转告了吉恩·皮埃尔·杜夏尔(Jean Pierre Duchatel),他在列日大学兽医系工作。需告诉大家的是,吉恩·皮埃尔·杜夏尔先生也是位鸽友,而且自1974年以来就是鸟类医学系的成员,一直与文德夫格教授(Vindevogel)共事。他们一起深入研究感染鸽子的各类病毒,并为Fort Dodge公司研制了多种疫苗,如 Colombovac PMV(副粘病毒疫苗),Colombovac Pox (鸽痘病毒)和Colombovac Paratyphus (副伤寒病毒)。目前,杜夏尔先生正负责一项由FCI(国际赛鸽联合总会)出资扶植的研究项目,研究可传染给信鸽的圆环病毒。  相似文献   

贸易,就业与工资     

Krug.  P 朱疆 《科学中国》1994,(8):6-10

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感悟、鉴赏和探究：文学作品教学的三种重要方法——关于文学作品教学的几点浅思     

周红阳． 《教学月刊》2004,(11):9-12

笔者以为，文学作品教学与非文学作品教学有许多共通之处，当以“文本”为依托、“语言”为核心、“理解”为基础、“能力”为目标，换言之，要紧扣文本，揣摩语言，理解内容，发展能力。但“以艺术形象的方式对以人为中心的社会生活的整体作审美反映”㈨是文学与其他社会科学的主要区别，可见文学的特点在于形象和审美，故文学作品的教学又必须通过对形象的感悟(体验)、鉴赏(品味)和探究(发现)等方式，以达到培养和提升学  相似文献   

Success in elite cycling: A prospective and retrospective analysis of race results     

Schumacher YO  Mroz R  Mueller P  Schmid A  Ruecker G 《Journal of sports sciences》2006,24(11):1149-1156

The development of peak performances is a main research focus in sports science. It is unclear how many former top junior athletes achieve success in the elite class later. The aim of the present study was to examine the careers of athletes who participated in major junior or adult/elite cycling events using prospective and retrospective analysis of competition results. The official results of major junior (age < or = 18 years) and elite (age > 18 years) cycling races from 1980 to 2004 were analysed. Age-related aspects, career lengths, and success were compared between riders who presented results in both junior and elite races (JUNIOR ELITE) and riders who had no junior race results (ELITE ONLY). Altogether, 27,454 results of 8004 athletes from 108 countries were collected. We found that 29.4% of the elite athletes had participated in junior World Championships, and that 34% of the participants in junior World Championships later participated in major elite competitions. JUNIOR ELITE athletes are significantly more successful in several cycling disciplines and have their first and last elite result at a younger age than ELITE ONLY athletes. No difference was found in career lengths. The data presented here emphasize the importance of long-term training programmes in the development of peak performance in cycling.  相似文献   

俄罗斯会出现“普京突破期”吗?     

弗亚切斯拉夫·科斯基科夫  胡雅娟 《对外大传播》2006,(1)

俄罗斯《论据与事实》 2005年12月7日文章很多读者都很想知道,俄罗斯现政府能否在历史上留下属于自己的一笔。俄罗斯有这样一个传统,就是总喜欢把各个历史时期以领导者的名字来命名。我们经常说到的有“列宁电气化时期”,“斯大林个人崇拜时期”,“赫鲁晓夫解冻时期”,“勃列日涅夫停滞期”, “叶利钦膨胀时期”。“当弗·普京把政权交接给下一任  相似文献   

俄罗斯田径教练经验谈     

B.门谢列科夫  苏全生 《成都体育学院学报》1993,(2)

短跑训练过程的组织是一个非常复杂的问题。比如说以前认为,增大运动量是提高成绩的最可靠手段,这好象是唯一正确的途径,因为大多数冠军和纪录创造者都是靠此取得好成绩的。但如今运动负荷量已达到很大,以至于对于高水平运动员来说,进一步提高运动量已无助于运动成绩的继续提高。  相似文献   

Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions     

Andersson H  Ekblom B  Krustrup P 《Journal of sports sciences》2008,26(2):113-122

The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.  相似文献   

人对历史的观察     

阿诺德．汤因比 《中学历史教学参考》1996,(4)

人对历史的观察未来尚未降临，过去已不复存在，因此，当我们合上史册的时候，过去了的事情都已是无可改变的了。然而，这不可改变的过去并不总会到处重复再现。处于不同的时空之中，它便会异彩纷呈，而我们所获知的信息的增减，也会改变其面貌，我们对过去事情的相互关系...  相似文献   

动热身活动     

兰．如特菜  张东彦 《体育科技信息》2002,22(3):19-21

当有人问高级教练员和运动员静拉热身活动的目的是什么时，回答很有趣，他们认为静拉伸热身活动可减少对运动员的损伤程度，但是这一点至今仍未被证明。实际上，最近POPe对此也提出了相反意见。  相似文献