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   18篇
  免费   0篇
  3篇
综合类   3篇
水产渔业   3篇
畜牧兽医   6篇
植物保护   3篇
  2023年   1篇
  2020年   1篇
  2017年   1篇
  2015年   1篇
  2012年   2篇
  2011年   3篇
  2009年   2篇
  2007年   2篇
  2001年   1篇
  1968年   1篇
  1967年   2篇
  1966年   1篇
排序方式: 共有18条查询结果,搜索用时 304 毫秒
1.
2.
3.
Zeylanicobdella arugamensis (Annelida: Hirudinea), a marine parasitic leech, is currently affecting different species of cultured groupers, hybrid groupers, snappers and sea bass in Malaysia. Dillenia suffruticosa (Dilleniaceae), a medicinal plant found in Sabah, has been selected in our experiment to kill the leeches as a natural control method. The leech‐infested hybrid groupers were collected from aquaculture facilities, and the isolated leeches were challenged against methanol extract of D. suffruticosa leaves. The experiment was carried out using various concentrations of the extracts such as 25, 50 and 100 mg/ml. The methanol extract showed significant antiparasitic activity against Z. arugamensis with 100% mortality at a concentration of 100 mg/ml in 14.39 ± 3.75 min., followed by 50 and 25 mg/ml in 32.97 ± 9.29 and 41.77 ± 5.40 min., respectively. The phytochemical composition of the extract was determined using GC‐MS analysis to understand the nature of the principal compounds responsible for its antiparasitic properties. The leaves of D. suffruticosa demonstrated the presence of different bioactive compounds of various natures with varying percentages. Thus, it could be revealed that the methanol extract of D. suffruticosa mainly contains vital phytochemical compounds and showed an effective antiparasitic activity against the harmful leeches of hybrid groupers.  相似文献   
4.
The energy and protein value for Guinea pigs (GP) of 9 forages (7 dicots and 2 grasses) and 5 hay-based diets was determined. The apparent faecal digestibility of dry matter, organic matter, crude protein and energy was measured on GP housed in metabolic cages. The forages and the diets were digested in vitro using pepsin and pancreatin hydrolysis and gas fermentation test to simulate stomach, small intestine and large intestine, respectively. Most of the dicots had high digestible crude protein content (152–201 g/kg DM) and the 2 grasses showed lower values (80–85 g/kg DM). Digestible energy content of the forages ranged between 5.79 to 13.08 MJ/kg DM. None of the forage species or hay-based diets provided sufficient energy to supply the 11.7 MJ/kg metabolic energy requirements. The influence of intestinal fermentation on energy and protein values was highlighted by correlations (P<0.05) between in vivo and in vitro data, including gas fermentation. It is the first time that such relationships are reported in single-stomach animals.  相似文献   
5.
Spectroscopic observations of the two stars near the pulsar CP 1919+21 are not sufficiently conclusive to permit an identification of either object with the source of the radio pulses. However, our most extensive series of photometric observations of a region of sky near the radio source position, which region includes the brighter of the two stars, suggests an approximately sinusoidal variation. It is significant that the period of the variation is double the period of the radio pulsations.  相似文献   
6.
In stellar astronomy, the future of automation techniques lies in their application to the largest telescopes. In such a case, the cost of automation is small compared to that of the telescope project as a whole, and is well repaid in the savings in observing time. A "stand-alone" capability for manual operation in event of computer breakdown is usually provided for systems like this; an example is the 107-inch (272-cm) telescope under construction at the McDonald Observatory of the University of Texas, which will be associated with an IBM 1800 computer.  相似文献   
7.
Bindelle, J., Ilunga, Y., Delacollette, M., Muland Kayij, M., Umba di M’Balu, J., Kindele, E. and Buldgen, A. Voluntary intake, chemical composition and in vitro digestibility of fresh forages fed to Guinea pigs in periurban rearing systems of Kinshasa (Democratic Republic of Congo). Tropical Animal Health and Production. The daily voluntary intake (DVI) of Guinea pigs (GP) fed 15 fresh forages used in periurban rearing systems of Kinshasa (Democratic Republic of Congo) was investigated. In order to determine the best forages combination for GP diet, DVI was compared to their nutritional value measured in vitro using 1) a pepsin-pancreatin hydrolysis, 2) an gas fermentation test on the hydrolysed residues with an inoculum prepared from GP faeces, and 3) the chemical composition of the offered feeds and the hydrolysis residues. The forages ranking based on the DVI was correlated to the NDF content, but not to their nutritional values determined in vitro. According to their high DVI (from 4.23 to 7.75 g/kg liveweigth), and their valuable in vitro nutritional values (crude protein ranging from 261 to 279 g crude protein kg−1DM, pepsin-pancreatin digestibilities of the dry matter from 0.55 to 0.59 and final gas production from 170 to 196 l kg−1DM), Desmodium intortum, Euphorbia heterophylla or Amaranthus hybridus, can be suggested to the farmers to complement the usual diet distributed to the GP based on Panicum maximum.  相似文献   
8.
Caligid copepods (Crustacea) known as sea lice are pests of cultured fish, causing serious diseases and economic losses in fish aquaculture worldwide. One species, Caligus sclerotinosus Roubal, Armitage & Rohde, 1983 (Caligidae), is considered a serious pest of the highly prized red seabream Pagrus major (Temminck and Schlegel, 1843) (Sparidae) cultured in Japan. Recently, in neighboring Korea, red seabream culture has intensified and almost replaced yellow tail culture. However, until now, there have been no reports on infection of this sea louse from red seabream in Korea. We surveyed 120 (20 fish per month) P. major from a sea ranched Tongyeong Marine Research Center aquaculture facility, Gyeongsangnamdo, Korea for six months in 2011 (June to November). We recorded severe infection by the sea louse C. sclerotinosus on the skin of P. major. Prevalence was 100%, mean intensity 7.06, maximum intensity 49, and minimum intensity 2. Adult females (624), males (219) and few chalimi (5) were observed and identified by their morphology. As an average of all our collections, less than 0.6% of individuals were chalimi. We suggest, therefore, that adults of C. sclerotinosus undergo ontogenetic host switching after their final moult. No infection of C. sclerotinosus was found on wild P. major collected from Tongyeong and Yeosu fish markets on the southern coast of Korea. Severe infection by this sea louse may cause secondary infections of the host. This copepod is already reported from Australia and Japan and hence, this is the first report from Korea. We expect this pest to have an impact on Korean red seabream fisheries equally serious to that being experienced in Japan.  相似文献   
9.
As part of a conservation initiative, captive-bred individuals of the endangered European mink Mustela lutreola were released to a Baltic island ‘sanctuary’, Hiiumaa Island (Estonia), and their survival was monitored over eight years. Altogether, 54 released mink were equipped with radio-collars between 2000 and 2003 and their survival and causes of death were studied as a function of sex, age, housing conditions before release and number of generations in captivity. Mortality was greatest (∼ 50%) during 1-1.5 months following release. The survival of males was significantly higher than that of females (25% decline in 21 days, and 10 days, for males and females, respectively). Releasing pregnant females appeared to be an unsuccessful strategy. There was no evidence that the number of generations for which the lineage of the released individuals had been bred in captivity had any effect on survival. The main cause of death was other carnivores and raptors, although this broad categorization may conceal a diversity of fatal scenarios.We recommend for the future that the European mink being prepared for release should be maintained in large naturalistic enclosures beforehand, that a preponderance of females should be released, and that the indications that younger animals make better candidates for release should be investigated.  相似文献   
10.
Tobacco streak virus (TSV), inciting cotton necrosis, exhibits multifarious symptoms. Common types of symptoms include, purplish brown, necrotic lesions in the leaves, squares, and petioles. Telangana (India) had the highest incidence of TSV (51.11 PDI - hybrid RCH659), among the surveyed locations including, Tamil Nadu, Andhra Pradesh, Telangana and Maharashtra states of India. Environmental factors greatly influenced the establishment of TSV in cotton. Minimum temperature (22.81 °C), relative humidity (81.42%), and leaf wetness (23.94 h) favoured maximum TSV incidence with a mean PDI of 30.68 at Annur, (Tamil Nadu, India). Serological assay through DAC-ELISA confirmed the presence of TSV in cotton samples expressing necrosis symptoms. Bioassay revealed that Chenopodium amaranticolor and Chenopodium quinoa are excellent indicator host plants with high virus titres. Further, molecular characterization revealed the conserved nature of the coat protein gene, among the TSV isolates infecting cotton in four different states (Tamil Nadu, Andhra Pradesh, Telangana, and Maharashtra).  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