全文获取类型
收费全文 | 121篇 |
免费 | 8篇 |
专业分类
林业 | 5篇 |
农学 | 3篇 |
基础科学 | 2篇 |
30篇 | |
综合类 | 8篇 |
农作物 | 8篇 |
水产渔业 | 12篇 |
畜牧兽医 | 40篇 |
园艺 | 8篇 |
植物保护 | 13篇 |
出版年
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1970年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 147 毫秒
1.
2.
A 4-year study of parasitoids attackingChrysoperla carnea (Stephens) in the cotton fields of Çukurova, Turkey, revealed the activities of three principal taxa:Telenomus sp. nr.suvae attacks the eggs ofC. carnea: Catolaccus sp. andBaryscapus sp. are larval and pupal parasitoids, respectively. In general, percent egg parasitism increased starting from the second half of June and into July, then decreased until the beginning of August before rising again at the end of growing season. During the early season, weekly parasitism was found to be as high as 94%. Overall, seasonal egg parasitism varied between 13.6% and 62.0% among all study sites. According to the results of a one-year field study at Hac?ali, total larval and pupal parasitism was found to be 12.5% and 55.6%, respectively. Therefore, different factors influencing the effectiveness of the generalist predatorC. carnea against cotton pests, and the differential effects of cotton treatments on both host and parasitoids, need to be evaluated. 相似文献
3.
Bahram Falahatkar Konrad Dabrowski Murat Arslan & Jacques Rinchard 《Aquaculture Research》2006,37(8):834-841
This study was conducted to examine the effects of different forms and concentrations of ascorbic acid (vitamin C), and different enrichment times (24 and 48 h post ovulation) on egg, embryo and alevin ascorbate concentrations and survival of rainbow trout (enrichment was at the ova stage). In experiments 1 and 2, fertilized eggs were immersed in water containing ascorbate at 0 (control), 100, 1000 mg L?1 l ‐ascorbic acid (AA) and 2000 mg L?1 l ‐ascorbyl monophosphate (AP). In experiment 3, 0 (control), 500 and 1000 mg L?1 AA neutralized (N) with NaOH, 1000 mg L?1 AA non‐neutralized (NN), 1000 and 2000 mg L?1 AP immersions were used. The mean total ascorbic acid (TAA) and dehydroascorbic acid (DHA) concentrations were measured before fertilization, at 3 and 24 h after fertilization, at the eyed stage, and in hatched alevins. We observed significant differences in TAA concentration at different immersion levels at 3 and 24 h after fertilization. Survival decreased significantly depending on the level of vitamin C, pH of the solutions and immersion time. We suggest that when broodstock rainbow trout do not have enough vitamin C in their ovaries, immersion of eggs in 1000 mg L?1 of neutralized AA may be useful. 相似文献
4.
Munir K Muneer MA Tiwari A Chaudhry RM Muruganandan S 《Veterinary research communications》2007,31(7):909-929
Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian
paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential
component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective
immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were
divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four
served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide
(CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the
next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid
organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated.
Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as
compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses
but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV
and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks. 相似文献
5.
Nanotechnology creates a new challenge for materials characterization because device properties now depend on size and shape as much as they depend on the traditional parameters of structure and composition. Here we show that Z-contrast tomography in the scanning transmission electron microscope has been developed to determine the complete three-dimensional size and shape of embedded structures with a resolution of approximately 1 cubic nanometer. The results from a tin/silicon quantum dot system show that the positions of the quantum dots and their size, shape, structure, and formation mechanism can be determined directly. These methods are applicable to any system, providing a unique and versatile three-dimensional visualization tool. 相似文献
6.
Dr. S. H. Arslan C. P. Mackenzie R. Brown J. T. Baxter 《Veterinary research communications》1983,6(1):51-58
The stage of hair growth which predominated in dogs not affected with hypothyroidism appeared to be breed-dependent. For example, in boxers, Labradors and collies, the resting stage (telogen) predominated, whereas in West Highland White terriers and cairn terriers the active stage (anagen) predominated. However, even in pet dogs kept mainly indoors, the proportion of hairs in anagen tended to increase during the winter months.In dogs affected with hypothyroidism, the proportion of hairs in anagen or telogen in members of a particular breed was the same as in the normal dogs of the breed. From this, it appeared that breed was more influential than hypothyroidism in determining the predominant phase of hair growth. 相似文献
7.
8.
Summary Four species of amphistomes were recorded from buffaloes in Peshawar region. The incidence of different species was determined.
The significance of amphistomes in causing disease is discussed.
Sumario Se registraron cuatro especies de Paramfistomas de bufalos en la región de Peshawar. Se determinó la incidencia de las diferentes especies. Se discute el significado de los amfistomas como causantes de Enfermedates.
Résumé 4 espèces d'amphistomes sont signalées chez les buffles de la région de Peshawar. L'incidence de ces différentes espèces est déterminée. L'importance de ces amphistomes sous l'angle de leur pouvoir pathogène est discutée.相似文献
9.
Chaudhry AS 《Journal of animal physiology and animal nutrition》2005,89(11-12):403-412
Two experiments compared the suitability of two commercial enzymes to estimate in vitro proteolysis of different proteins. Experiment 1 compared the proteolytic activity over various incubation times of a microbial enzyme (protease from Streptomyces griseus) with a plant enzyme (papain from Papaya latex) by using either 1.33 (high, H) or 0.4 (low, L) units (U, amount) of each enzyme per mg crude protein (CP) of purified proteins including bovine (BA) or egg albumin (EA). Experiment 2 compared the activity of 0.66 U of each of these enzymes per mg CP of semi-purified proteins including casein, wheat gluten (WG) and maize gluten meal (MG). Each incubation was terminated by adding trichloroacetic acid (TCA) and the TCA soluble supernatant collected to estimate concentration of total amino acids (AA) as the measure of proteolysis of each protein over each time. The data on proteolysis over time were fitted into a non-linear model to derive constants for solubility (a) and rate (c) and extents (a + b) of proteolysis of each food by each amount of each enzyme. All data on proteolysis over time and the derived constants were statistically analysed to study the effect of food, enzyme, amount and their interactions. Significant differences were observed between foods, enzymes, enzyme amount (H vs. L for Experiment 1 only) for the proteolysis at most incubation times in both experiments (p<0.001). The mean proteolysis over all times for BA was 1.6 (SD, 0.52) times greater than EA (p<0.001). While the protease gave about four times (SD, 2.1) more proteolysis than papain (p<0.001), the high amount of enzyme gave only about two times (SD, 0.28) greater proteolysis than that of the low amount (p<0.001). On average, the protease was over three times faster (c) than papain (p<0.001) and high amount was two times faster than the low amount of enzyme (p<0.001). While both purified foods were similar in solubility (p>0.05), they differed in the rate and extent of proteolysis (p<0.001). The BA was degraded about four times faster than EA (p < 0.001). Amongst semi-pure proteins, casein gave the highest but MG the lowest proteolysis at each incubation (p<0.001). However, the magnitude of proteolysis depended upon enzyme, food and hours of incubation. On average, casein was degraded at a much faster rate than WG or MG by both enzymes. It appeared that the protease and not papain can be used to estimate in vitro proteolysis of pure and semi-pure food proteins. However, further studies are needed to standardise the relevant procedures when using protease to estimate proteolysis of ruminant foods. 相似文献
10.
Establishment of ornamental and aesthetic plants in hot, arid conditions of India is difficult due to the prevailing climatic, edaphic and biotic factors. Effect of turfgrass on the growth of ornamental plants in hot arid conditions has not been studied so far anywhere in the world. A study was conducted on the campus of Arid Forest Research Institute, Jodhpur, India to assess the performance of a few ornamental plant species in combination with turfgrass and without turfgrass with respect to different soil tilling intervals. Growth of plants was better with turfgrass than without turfgrass. We suggest adopting a soil tilling interval of 30 days to achieve optimum growth of ornamental plant species in terms of height and crown diameter. Our results can help reduce labor costs and achieving better landscapes in fewer days in hot urban conditions of Indian sub continent. 相似文献