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   99篇
  免费   9篇
林业   5篇
农学   1篇
  22篇
综合类   1篇
农作物   6篇
水产渔业   3篇
畜牧兽医   48篇
园艺   6篇
植物保护   16篇
  2021年   1篇
  2020年   3篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   8篇
  2015年   3篇
  2014年   4篇
  2013年   10篇
  2012年   10篇
  2011年   2篇
  2010年   7篇
  2009年   3篇
  2008年   7篇
  2007年   13篇
  2006年   2篇
  2005年   1篇
  2004年   2篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1997年   2篇
  1992年   2篇
排序方式: 共有108条查询结果,搜索用时 31 毫秒
1.
2.
Plant Foods for Human Nutrition - St. John’s wort has been used for centuries in traditional medicine of many cultures, and nowadays it is well-known as a clinically important antidepressant...  相似文献   
3.
Tineola bisselliella is a common pest on natural fabrics of economic importance. Two commercially available repellents for use against adult webbing clothes moths were tested for their efficacy in dual- and no-choice bioassays. Oil of cloves and citral in combination, as well as citronellol scented with oil of lavender showed promising repellent effects for 4 weeks when applied in small compartments of a wardrobe. Although the repellent efficacy was not 100% under the conditions tested, the usage of essential oils in combination with other infestation prevention techniques is discussed.
Zusammenfassung Die KleidermotteTineola bisselliella Hum. ist einer der wirtschaftlich bedeutenden tierischen Wollzerstörer. Auch Pelze, Felle, Polsterhaare und Federn werden von dem weit verbreiteten Kleinschmetterling aus der Familie der Tineidae befallen. In der Praxis gilt es vor allem Kleidungsstücke, die z. B. saisonbedingt für längere Zeit ungenutzt in einem Kleiderschrank aufbewahrt werden, vor dem Befall durch die Kleidermotte zu schützen. Hierfür stehen dem Verbraucher neben den konventionellen Bekämpfungsmitteln mit den Wirkstoffen Kampfer, Naphthalin und Paradichlorbenzol sowie pyrethrum- und pyrethroidhaltige Mittel auch Präparate zur Verfügung, die auf die repellierende Wirkung von ätherischen Ölen zurückgreifen. Die abstoßende Wirkung von Nelkenöl in Kombination mit Citral und von Citronellol parfümiert mit Lavendelöl auf die Falter der Kleidermotte wurde auf vergleichbare Eigenschaften untersucht. In Wahlversuchen wurden deutliche Repellent-Wirkungen der Mottenschutz-Präparate sichtbar. Die Präparate zeigten gute Wirkungen, wenn sie zum Schutz gegen den Zuflug von Kleidermotten an wollhaltigen Stoffen in kleinen Kompartimenten eines Kleiderschrankes ausgelegt waren. Auch in Zwangsversuchen hatte dieser Befund zum Teil Bestand. Bei längeren Versuchszeiten wurden allerdings verstärkt Fraßschäden durch Larven an den Wollstoffen festgestellt. Dies ist darauf zurückzuführen, daß Mottenweibchen nicht mehr in dem Maße repelliert wurden und ihre Eier an den Stoffen ablegten.


This article reports the results of research only. Mention of a proprietary product or pesticide does not constitute an endorsement or a recommendation for its use by the Federal Biological Research Centre for Agriculture and Forestry or by the USDA-ARS.  相似文献   
4.
Archaeologists often encounter problems in interpreting the genesis of layers and the context in which specific materials occur in excavations. Field visits of geologists, soil scientists or biologists can solve a number of questions, but often, problems remain that only can be studied by microscopic research as, for example, soil micromorphology and palynology. In the past, the employment of these two disciplines, one in earth science and one in biology, generally occurred independently of each other, also in interdisciplinary research and contract research. Consequently, results could not always be correlated, permitting only a restricted integration of data. It was realised that soils, as archives, contain much more information than generally utilised. A skillful employment and balancing of both specialties create a real integrated approach that offers a substantially improved interpretation potential without hardly additional efforts and costs. The results of 7 years of experience were very stimulating and presented here.In this article, the essence of soil micromorphology and palynology applied to archaeology is briefly outlined and illustrated by selected examples of the different research themes covered, showing the possibilities and results of integrated research. Both specialties generate essential information that, when combined and integrated properly, lead to improved understanding of the landscape genesis and human activities in the past. To be able to employ the full interpretive potential of this integrated approach, the research procedures followed by both specialties had to be compared. The key requirements for optimal integration of each other's databases comprised a combined effort to compare the pros and cons during the first four steps of the research procedure: defining research questions, field survey, selection of sampling locations and sampling. This approach enabled optimal correlation of the individual results, made cross-checking and references possible and led to higher levels of interpretation that would not have been possible otherwise. The integrated research elucidated lacunae in the other's discipline, resulting in a distinctly more complete reconstruction of paleoenvironments and past land uses, important research themes of archaeologists for the specialties concerned.  相似文献   
5.
6.
In recent years, several species of alien scale insects have arrived and spread rapidly through European and Mediterranean countries. One hundred and twenty‐nine species of alien scale insects have so far been recorded in Europe. This paper presents a list of alien scale insect species for Croatia, comprising 56 species from 8 different families. Four of them are new records for Croatia: Aonidiella taxus Leonardi, 1906, Ichnaspis longirostris (Signoret, 1882), Phoenicococcus marlatii (Cockerell, 1899) and Spilococcus mammillariae (Bouche, 1844). The majority of species recorded belong to the following families: Diaspididae (28 species), Coccidae (12 species), Pseudococcidae (10 species), Eriococcidae (two species). The scale insect families Dactylopidae, Margarodidae, Ortheziidae and Pheniococcidae comprised only one recorded alien species each. During the time frame covered in the review (from the beginning of the 20th century until 2015), the majority of alien scale insect species (23) were registered in the period from 2000 to 2015. Data on the origin of introduced alien scale insects shows that the majority of the species originate from Asia (22 species), followed by North America (6 species), Africa, Australia and Central America (5 species each) and South America (4 species), with 9 species being of unknown origin.  相似文献   
7.
8.
The effect of Diesel fuel on stability of aggregates, plasticity index and shear strength of two soil materials The influence of Diesel fuel contamination on mechanical properties of soil are investigated with regard to the retreatment of materials after a cleaning process. Following aspects are examined in laboratory tests: waterstability of aggregates, plasticity index and shear strength parameter. The used soil materials are mixed samples of a Luvisol (=Bt) and a tidal influenced alluvial clay sediment of a Gley (=Klei). The aggregate stability of Bt material is rising at increasing Diesel fuel contaminations due to a hydrophob effect on the surfaces of the aggregates. This influence cannot be shown for clay material. On the other hand the plasticity index shows a decrease for low Diesel fuel contaminations, because the Diesel fuel acts directly to the particle surfaces. At increasing contaminations these effects are overlayed by increasing viscosity and shear strength of water and Diesel fuel phases or emulsions. The increase in stability of aggregates is not evident in a shear box test. The Diesel fuel shows no influence to angle of internal friction for both investigated materials. On the other hand there is an effect to the cohesion. This phenomenon could be explicated with above mentioned increase in cohesion due to an increase in shear strength and viscosity of a two phase system.  相似文献   
9.
The objectives of this study were to assess the effects of the production systems of wheat from different production systems on the mortality, progeny production and preference of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The factors tested were production system (integrated [INT], organic [ORG], biodynamic [BD] and control), which differed in plant protection and fertiliser procedures during plant growth and development; exposure interval (7, 14 and 21 d); relative humidity (r.h.) (55% and 75%) and temperature (20°C, 25°C and 30°C). Mortality after 7 d increased with the temperature increase and decreased with the increase in r.h. in most of the tested combinations. The mortality of weevils was higher in ORG compared to INT-produced wheat after 7 d. Progeny production was recorded 56 d after removal of parental adults and was higher at 75% r.h. in comparison to 55% r.h. At 55% r.h. and 20°C, progeny was 60.8% higher when S. zeamais were exposed to ORG in comparison to INT-produced wheat. Wheat from different production systems influenced mortality rates which were higher in alternative compared to INT production systems under optimal conditions for wheat storage (low temperature and r.h.). The reverse was recorded for temperature and r.h. increase. Progeny was not affected by wheat from various production systems. Significantly more S. zeamais adults were found in traps containing wheat from BD and control in comparison to INT. An understanding of the agricultural processes, biotic and abiotic factors which alter the post-harvest response of storage pests could be useful for the development of efficient post-harvest strategies for ORG and BD farms and the processing industry.  相似文献   
10.
Enteric duplication is a rare developmental malformation in people, dogs and cats. The purpose of the present report is to describe the first case of a rectal duplication cyst in a 7-year-old domestic shorthair cat presenting for acute constipation and tenesmus. On rectal palpation a spherical mass compressing the lumen of the rectum could be felt in the dorsal wall of the rectum. A computed tomography (CT) scan confirmed the presence of a well demarcated cystic lesion in the pelvic canal, dorsal to the rectum. The cyst was surgically removed via a perineal approach. No communication with the rectal lumen could be demonstrated. Histopathological examination was consistent with a rectal duplication cyst. Clinical signs resolved completely after excision of this conjoined non-communicating cystic rectal duplicate.  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