全文获取类型
收费全文 | 154篇 |
免费 | 3篇 |
国内免费 | 14篇 |
出版年
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 14篇 |
2006年 | 14篇 |
2005年 | 5篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有171条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
樟脊网蝽生物学特性观察 总被引:2,自引:0,他引:2
樟脊网蝽是香樟的重要害虫,在上海1年发生4代。4月下旬越冬卵始孵,9月下旬开始出现越冬卵。成虫末见期在11月中旬。经室内饲养,樟脊网蝽第三代各龄若虫历期为:一龄61.45±7.8h,二龄48.00±7.6h,三龄43.43±7.6h,四龄51.00±8.0h,五龄70.50±7.5h,整个若虫期历期为281.92±14.8h。第三代野外雌雄比为1:4.07。第三代每雌产2~96粒。日最高产卵量为34粒/头,孤雌可产卵。10%灭百可2000倍稀释液和50%杀螟松2000倍稀释液喷雾防治效果可达93%以上。 相似文献
6.
大叶黄杨长毛斑蛾的生物学研究 总被引:1,自引:0,他引:1
大叶黄杨长毛斑蛾于1990年在山东威海地区首次发现,是为害大叶黄杨的重要害虫,一年发生1代,以卵在枝条上越冬,翌年4月初出现幼虫,5月中旬初开始结茧化蛹,10月底始见成虫,作于1990-1993年对该虫的形态特征,生活史及为害习性进行了观察研究,并提出综合防治措施。 相似文献
7.
R.M. Kaplan J.B. Dame G.R. Reddy C.H. Courtney 《International journal for parasitology》1997,27(12):1585-1593
Accurate snail intermediate host infection prevalence data have the potential to be extremely useful in determining seasonal transmission dynamics of Fasciola hepatica. Because the microscopic techniques currently used lack the sensitivity and specificity necessary to obtain meaningful infection prevalence data, we developed a highly accurate and efficient DNA probe assay. The assay has a sensitivity of 100%, a specificity of >99%, easily detects a single miracidia and does not cross-hybridize with DNA of Fascioloides magna, Paramphistomum liorchis or Heterobilharzia americana, trematodes that share the same intermediate host and enzootic range as Fasciola hepatica. Using this assay, we determined the prevalence of F. hepatica in its snail intermediate host, Fossaria cubensis, during the second year of a 2-year study on the epizootiology of Fasciola hepatica in Florida. The overall infection prevalence of snails assayed in this study (n = 5246) was 1.5% and ranged from 0.1% to 3.1% for individual cattle ranches. Additionally, infection prevalence differed significantly for successive size groupings of snails, varying from 0% for 1-mm snails to 18.5% for 9- and 10-mm snails. The accuracy and efficiency of the DNA probe assay reported here for determining snail infection prevalence offers an inexpensive alternative to tracer animal studies for determining the epizootiology of F. hepatica. 相似文献
8.
9.
Daniel Molloy 《Journal of nematology》1979,11(4):321-3287
Mesomermis camdenensis n. sp. is described from larvae of Simulium tuberosum (lundstroem) collected in Camden Valley Creek, Washington County, New York. This species possesses a barrel-shaped vagina, vulval flap. two short separate spicules, terminal mouth, six longitudinal chords, six cephalic papillae, large sexually dimorpbic anaphids, an esophagns of uniform width which extends for less than one-third of the body length, and a cone-shaped tail directed ventrally without appendage. Juveniles also are described and illustrated.A detailed morphological comparison with the mermithid M. flumenalis Welch is presented. The most pronounced morphological differences between these species are in the shape of the vulva, juvenile tail, and infective stage. Cross-mating trials support the integrity of the new species.The life cycle of M. camdenensis is closely synchronized with that of its primary host, S. tuberosum larvae. Infected S. tuberosum larvae were first collected in May. Emergence of postparasites from late instars took place from mid-June through mid-October. Sampling data indicate a lower susceptibility to infection among S. venuslum Say larvae. 相似文献
10.
以全麦粉和酵母粉(10:1)为饲料,分别在8种温度(17.5-35℃)及5种相对湿度(50%-90%RH)条件下系统地研究了嗜虫书虱的生物学特性,获得了其在不同温、湿度组合情况下的生长发育、生存和繁殖的一系列特性和参数。结果表明,在75%RH、20-35℃范围内,世代发育历期在71.9-21.7天之间。世代发育起点温度和有效积温分别为15.7℃和460.7日·度。各虫态及世代存活率均以27.5℃时最高,温度过高或过低均不利于该虫存活。成虫平均寿命在64.4-32.4天之间。每雌平均产卵量为21.1-13.9粒。在28℃条件下,较高的相对温度有利于该虫生长发育和繁殖。相对湿度低于50%或温度低于17.5℃,该虫均不能完成世代发耷。总体来看该虫生长发育、繁殖的最适温区为28-30℃,最适相对湿度在80%—90%之间并就该虫在我国分布及为害严重的原因进行了探讨。 相似文献