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   90篇
  免费   0篇
林业   5篇
农学   7篇
  1篇
综合类   7篇
农作物   2篇
水产渔业   11篇
畜牧兽医   36篇
植物保护   21篇
  2014年   1篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   2篇
  2005年   2篇
  1998年   1篇
  1997年   2篇
  1996年   6篇
  1995年   2篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1991年   4篇
  1990年   6篇
  1989年   2篇
  1988年   7篇
  1987年   5篇
  1986年   1篇
  1983年   3篇
  1982年   1篇
  1981年   3篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1967年   1篇
  1964年   1篇
  1963年   1篇
  1960年   1篇
  1958年   1篇
  1955年   1篇
  1954年   2篇
  1946年   1篇
排序方式: 共有90条查询结果,搜索用时 156 毫秒
1.
2.
3.
One method of increasing the value of aquacultured product is to produce fillets that are fortified with minerals that are beneficial to human health – that is enhance the functionality of an already healthy product. A good candidate mineral in this regard is selenium (Se) which is of vital importance to normal metabolism in humans. In order to evaluate the dose response and tissue accumulation of supplemental dietary Se, a study was undertaken with hybrid striped bass (HSB). Animals were fed diets supplemented with either organic (0–3.2 mg kg?1 as SelPlex®) or inorganic (0.2 and 0.4 mg kg?1 as sodium selenite) Se for 6 weeks. Because basal fishmeal‐based diets contained 1.22 mg Se kg?1, doses of Se delivered equated to 1.22–4.42 mg kg?1. At trial end, greatest weight gain was observed in fish receiving 0.2 mg Se kg?1, irrespective of form (organic/inorganic). Se accumulation in HSB liver and fillet revealed a classical dose‐response once a threshold level of 0.2 mg Se kg?1 was surpassed. Greatest tissue accumulation of Se was observed in fish fed the 3.2 mg Se kg?1 level (P > 0.0001). A 100 g portion of Se‐enhanced HSB fillet would contain between 33 and 109 μg Se, amounting to a dietary intake of between 25 and 80 μg Se; a level that would satisfy present daily intake recommendations. Comparison of tissue Se levels indicated that the muscle provides a more conspicuous gauge of dietary Se dose‐response than does liver. Dietary treatments of between 0.4 and 1.6 mg organic Se kg?1 reduced (P < 0.024) plasma glutathione peroxidase (GSH‐Px) activity. No differences were observed in ceruloplasmin, lysozyme or GSH‐Px activities between organic and inorganic Se when delivered at the 0.2 mg Se kg?1 level. Ceruloplasmin, lysozyme and GSH‐Px levels were elevated (P ≥ 0.025) in fish fed the diet containing 0.4 mg inorganic Se kg?1.  相似文献   
4.
Five dogs with unilateral thoracic limb lameness, neurologic deficits, muscle atrophy, and pain, or a combination of these signs, were examined using ultrasonograghy. Large, hypoechoic tubular masses that displaced vessels and destroyed the normal architecture were found in each dog. The affected axilla of each patient was then imaged with computed tomography or magnetic resonance to fully assess the extent of the masses. We describe the use of ultrasound in screening patients for brachial plexus tumors.  相似文献   
5.
Five hybridoma cell lines secreting antibodies (MAbs) recognizing zoospores of S. subterranea were raised from splenocytes of mice. One MAb also weakly recognized plasmodia/zoosporangia and cystosori of S. subterranea , and another recognized only plasmodia/zoosporangia in plate-trapped antigen ELISA. Polymyxa graminis was recognized most strongly out of 26 micro-organisms other than S. subterranea against which the MAbs were tested. Most were recognized only weakly or not at all. The MAb that recognized zoospores of S. subterranea most strongly detected as few as three zoospores per microtitre plate well when 12 replicate wells per treatment were arranged randomly on plates and absorbance values subjected to analysis of variance. The sensitivity of detection was not improved by mixing antibodies, using a biotin-streptavidin amplification system, or by using a double antibody sandwich system. Zoospores of S. subterranea flushed from soil were detected only after unrealistically large numbers of cystosori had been added. They were not detected in samples of naturally infested soil removed from a field shortly after a severely scabbed potato crop had been harvested.  相似文献   
6.
An orthotopic colon graft based on the middle colic artery and vein was implanted with microvascular technique and a stapling instrument in five dogs. The grafts were successful in four dogs. A similar colon autograft was used to replace the entire thoracic esophagus in five dogs. The recipient vessels were the left carotid artery and left external jugular vein. Four of the grafts failed because of kinking and thrombosis of the arterial supply (2 dogs) or the venous outflow (2 dogs). One graft, which had a viable vascular supply, developed a severe leak at the colon-to-stomach anastomosis, and the dog was euthanatized on day 3. The recipient vascular pedicle was modified and used successfully to replace a portion of the cervical esophagus in three dogs. The grafts survived, the dogs could swallow liquids and semisolid food well, and, at necropsy after 4 weeks, the anastomotic sites were well healed. The graft sites contained essentially normal colon mucosa.  相似文献   
7.
Climatic changes over the North Pacific which began in the mid 1970s, peaked in the early 1980s, and ended by the late 1980s, appear to have altered productivity at various trophic levels in the marine ecosystem in the central North Pacific. The climatic change resulted in increased mixed layer depth and the frequency of deep mixing events, particularly during January-March. A number of biological time series for species ranging from primary to apex levels in the North-western Hawaiian Islands, show corresponding declines in productivity of 30–50% from the early 1980s to the present. We hypothesize that during the early 1980s, increased mixing due to the climate event resulted in greater nutrient input into the euphotic zone and ultimately increased ecosystem productivity. Productivity over a range of trophic levels declined when the climate event ended.  相似文献   
8.
Seed of Acer pseudoplatanus was obtained from six widely scatteredlocations in Europe, and seedlings from these seed-sources weregrown on 25 different soils, covering a wide range of soil properties.Seedlings from four seed-sources of Betula verrucosa were alsogrown. There was a very wide variation in growth on the differentsoils, and between the two species; but relatively little variationbetween seed-lots within a species, and no significant interactionbetween seed-lot and soil, over the 2-year period of the experiment.It is concluded, therefore, that any one of the seed-lots usedin this experiment could have been used to assess the responseof seedlings of that species to changes in soil type, and thatvariation in growth due to genetic differences within thesespecies is likely to be small in comparison to the variationdue to soil conditions.  相似文献   
9.
A 3-year-old dog with cervical myelopathy resulting from a vascular anomaly is described. Marked intradural-extramedullary spinal cord compression was observed, in association with multilevel ectatic anastomotic radicular arterial branches connecting the left and right vertebral arteries. A nonpatent proximal segment of the right subclavian artery had resulted in compensatory enlargement of the left vertebral artery. Flow within the right vertebral artery was retrograde and fed into the patent distal segment of the right subclavian artery. Multiple imaging techniques including myelography, computed tomography, magnetic resonance imaging, and selective digital angiography were used to document this anomaly. To reduce spinal cord compression the largest collateral vessel was embolized without complication. Good clinical response was observed within 6 weeks and improved clinical neurologic function was maintained at the time of a 12-month re-evaluation.  相似文献   
10.
Pharmacokinetics of fenbendazole in dogs   总被引:1,自引:0,他引:1  
Fenbendazole was administered to dogs at a dose rate of 20 mg/kg body weight on a single occasion in gelatin capsules, on 5 consecutive days in feed, and on a single occasion as an alginate suspension. It was also administered at a dose rate of 100 mg/kg body weight on a single occasion in feed. Following single administration of 20 mg/kg fenbendazole mean maximum concentrations (Cmax) of the parent drug and its known active sulphoxide metabolite were 0.42 +/- 0.05 and 0.31 +/- 0.05 microgram/ml, respectively. Mean times until maximum concentrations were achieved (tmax) were 12.67 +/- 4.18 and 15.33 +/- 2.81 h, respectively, and areas under the plasma concentration-time curves (AUC) were 5.83 +/- 0.65 and 4.60 +/- 0.57 microgram.h/ml, respectively. Administration in feed increased the apparent bioavailability and administration for 5 consecutive days provided sustained plasma concentrations, generally greater than 0.2 microgram/ml. Administration as an alginate did not increase bioavailability or extend the persistence in plasma. It did increase the tmax to 16.80 +/- 2.93 and 20.00 +/- 2.53 h for fenbendazole and its sulphoxide metabolite, respectively. Increasing the dose from 20 mg/kg to 100 mg/kg did not substantially increase the Cmax or AUC.  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