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   197篇
  免费   2篇
  国内免费   1篇
林业   1篇
农学   10篇
  7篇
综合类   37篇
农作物   5篇
水产渔业   2篇
畜牧兽医   118篇
园艺   2篇
植物保护   18篇
  2019年   2篇
  2018年   2篇
  2016年   3篇
  2014年   2篇
  2013年   8篇
  2010年   4篇
  2009年   3篇
  2008年   5篇
  2007年   5篇
  2006年   3篇
  2002年   5篇
  2000年   8篇
  1999年   2篇
  1998年   3篇
  1997年   6篇
  1996年   5篇
  1995年   5篇
  1994年   3篇
  1993年   4篇
  1992年   5篇
  1991年   6篇
  1990年   4篇
  1989年   3篇
  1987年   5篇
  1986年   6篇
  1985年   7篇
  1984年   8篇
  1983年   6篇
  1982年   5篇
  1981年   4篇
  1980年   2篇
  1979年   3篇
  1977年   4篇
  1974年   2篇
  1971年   2篇
  1968年   2篇
  1966年   1篇
  1965年   1篇
  1962年   1篇
  1961年   1篇
  1960年   2篇
  1959年   4篇
  1957年   3篇
  1956年   3篇
  1955年   4篇
  1954年   1篇
  1953年   6篇
  1952年   1篇
  1950年   6篇
  1946年   3篇
排序方式: 共有200条查询结果,搜索用时 15 毫秒
191.
Five dogs with nasal aspergillosis were treated by surgical exposure and delayed closure of the nasal cavity and involved frontal sinus. Diseased tissue was excised, and 10% povidone-iodine solution was applied three times daily with cotton-tipped applicators. Skin wounds were closed at weeks 6 through 8. In one dog, the frontal sinus was partially obliterated with a temporalis muscle flap before skin closure. At months 6 through 34, all dogs were clinically free of aspergillosis. Open treatment has potential clinical application as a primary approach to nasal aspergillosis or for cases that are unresponsive to previous medical management.  相似文献   
192.
Reasons for performing study: Previous studies have suggested that agreement between equine veterinarians subjectively evaluating lameness in horses is low. These studies were limited to small numbers of horses, evaluating movement on the treadmill or to evaluating previously‐recorded videotape. Objectives: To estimate agreement between equine practitioners performing lameness evaluations in horses in the live, over ground setting. Methods: 131 mature horses were evaluated for lameness by 2–5 clinicians (mean 3.2) with a weighted‐average of 18.7 years of experience. Clinicians graded each limb using the AAEP lameness scale by first watching the horse trot in a straight line only and then after full lameness evaluation. Agreement was estimated by calculation of Fleiss' (κ). Evaluators agreed if they picked the same limb as lame or not lame regardless of the severity of perceived lameness. Results: After only evaluating the horse trot in a straight line clinicians agreed whether a limb was lame or not 76.6% of the time (κ= 0.44). After full lameness evaluation clinicians agreed whether a limb was lame or not 72.9% of the time (κ= 0.45). Agreement on forelimb lameness was slightly higher than on hindlimb lameness. When the mean AAEP lameness score was >1.5 clinicians agreed whether or not a limb was lame 93.1% of the time (κ= 0.86), but when the mean score was ≤1.5 they agreed 61.9% (κ= 0.23) of the time. When given the task of picking whether or not the horse was lame and picking the worst limb after full lameness evaluation, clinicians agreed 51.6% (κ= 0.37) of the time. Conclusions: For horses with mild lameness subjective evaluation of lameness is not very reliable. Potential relevance: A search for and the development of more objective and reliable methods of lameness evaluation is justified and should be encouraged and supported.  相似文献   
193.
Pharmacokinetics of dantrolene sodium in horses   总被引:1,自引:0,他引:1  
The pharmacokinetics of dantrolene sodium were investigated in horses following both intravenous (2 mg/kg) and intragastric (4 mg/kg) administration. Two ponies also received dantrolene sodium intravenously (2 mg/kg) in a pilot study to obtain preliminary kinetic data and to determine urinary and biliary excretion of the intact drug. Distribution and elimination of dantrolene was rapid, resulting in an elimination half-life of 129 +/- 8 (SEM) min and a whole body clearance of 4.16 +/- 0.52 ml/min/kg. Following intragastric administration, dantrolene rapidly acheived peak concentrations within 1.5 h, but was incompletely absorbed, with a bioavailability of 39 +/- 10%. Small amounts of intact drug were recovered in urine and bile. Based upon disposition kinetics of dantrolene in these studies, intravenous and intragastric dosage regimens were determined which would maintain blood dantrolene concentrations within the predicted clinically effective range.  相似文献   
194.
Thoracic duct embolization was created by injecting an isobutyl 2-cyanoacrylate/iophendylate (IBCA) mixture through a cannulated mesenteric lymphatic vessel in eight normal dogs. Aqueous contrast lymphangiography was repeated at minute 10 and week 6. Six dogs were euthanatized at week 6 and two dogs at month 6. Embolization with 1.5 to 3.9 ml of the mixture resulted in complete obstruction of the thoracic duct in all eight dogs. Results of lymphangiography in six dogs at week 6 showed a persistent, complete obstruction of the thoracic duct in six dogs and alternate lymphaticovenous anastomoses in four dogs. Histologically, there were a sclerosing granulomatous response surrounding the lymphatic embolus, mild congestive changes in the mesenteric lymph nodes, and mild lacteal dilatation in the jejunum. The procedure was well tolerated with only a few complications. One dog suffered partial thrombosis of the cranial vena cava by the injected material with later dislodgement and embolization of a pulmonary artery branch. Modifications have been made in the injection procedure to avoid this complication. This technique for occlusion of the thoracic duct shows potential for clinical use in the management of canine chylothorax. The obstruction appears to be complete and permanent, and surgical/anesthetic time is decreased greatly from previously described procedures.  相似文献   
195.
This study aimed to establish a culture system that improves the in vitro development of caprine preantral follicles. In a first experiment, follicles were encapsulated as a single unit per bead and cultured singly or in groups or with five follicles in the same alginate (ALG) bead for 18 days. In a subsequent experiment, the “five follicles per bead” design was chosen to culture in ALG, fibrin–alginate (FA) or hyaluronate (HA) for 18 days. In a third experiment, we chose the five follicles per bead in FA to culture for 30 days. The culture set‐up of five follicles per ALG bead increased antrum formation and follicle diameter compared to the other culture designs (p < .05). Moreover, under this condition, 44.44% of the oocytes from in vitro cultured preantral follicles reached meiotic resumption. A significant increase of follicle diameter occurred in attachment system and FA (p < .05), but the ALG condition reached the highest among all groups on day 18 (p < .05). Follicles encapsulated in matrix produced more estradiol and progesterone than attachment system (p < .05). The expression of MMP‐9 mRNA was higher in FA than in other groups (p < .05) and similar to antral follicles from in vivo control (p > .05). Only FA group resulted in oocytes matured. After 30 days, oocytes from preantral follicles in vitro grown in FA developed to eight‐cell parthenotes. In conclusion, a culture system using FA supported the development of caprine preantral follicles cultured in group and included in the same bead of hydrogel, improving the oocyte maturation and producing parthenotes.  相似文献   
196.
The relationship between the cultural and biochemical characteristics of 22 strains of Bacteroides nodosus and their virulence for sheep was examined. Virulent, intermediate and benign strains were recognised. Although there was some relationship between virulence and colony morphology on hoof medium with 4% agar, colonies of one virulent and 4 intermediate strains resembled those of benign strains. However, on hoof medium with 2% agar and on blood Euonagar, colonies of this virulent and one intermediate strain differed from each other and the other 3 intermediate strains, which in turn differed from the benign. The degree of piliation, as assessed by electron microscopy, was not a reliable indicator of virulence in strains not possessing a beaded colony type. Together, the results of colony morphology and proteolytic tests such as zymogram, degrading proteinase and elastin-agar tests allowed better discrimination of virulent and benign strains. Intermediate strains generally possessed virulent protease activity. In strains with benign zymogram patterns, activity bands 2 and 3 were more labile than in strains with virulent patterns. The addition of CaCl2 to the culture medium resulted in greater stability of proteolytic activity, particularly with benign strains, and prevented the disappearance of protease activity in the band 5 position in virulent, intermediate and benign strains during prolonged incubation. There were slight differences in the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) patterns of outer membrane proteins of some benign strains but those of intermediate category resembled virulent strains. There was some relationship between the apparent Mr of the pilin monomer on SDS-PAGE gels and serogroup specificity.  相似文献   
197.
针对《现代养殖设施与设备》课程没有规范教材的现状,探索符合人才培养目标和规格、适应市场需求的特色应用型教材建设,为应用型人才培养提供知识载体。并通过进一步实践,为教材的修订完善明确了方向。  相似文献   
198.
The effect of night feeding and feeding frequency on exocrine pancreatic secretion was studied in five chronically catherized growing pigs (16 to 31 kg). Feeding during the night (2200 to 2400 h) as compared to the day (1000 to 1200 h) tended to stimulate cholesterol ester lipase activity and tended to lower the colipase : lipase ratio in the pancreatic juice, but no effect on volume output, protein output and the activities of trypsin, chymotrypsin, amylase, lipase and colipase could be demonstrated. Feeding 12 small meals between 0800 and 2000 h as compared to one large meal (1000 to 1200 h) daily, altered the pattern of exocrine pancreatic secretion, tended to stimulate protein output by 44 %, chymotrypsin activity by 29 % and lipase activity by 46 %. These observations strengthened the theory that exocrine pancreatic secretion is partly regulated by feed intake per se and does not only depend on the amount of feed consumed. Feeding 12 small meals versus one large meal, compared at the same total daily feed intake, lowered the colipase : lipase ratio by 32 %. It can be concluded that feed intake pattern affected exocrine pancreatic secretion.  相似文献   
199.
A chewable tablet incorporating ivermectin and pyrantel was tested in 12 Beagle dogs for efficacy against the adult hookworm, Ancylostoma braziliense. The dogs were administered infective larvae of A braziliense orally. Twenty-one days after infection the dogs were weighed and allocated randomly to receive either an oral treatment with ivermectin and pyrantel in a beef-based chewable tablet or no treatment. The chewable tablet was a commercially available product, which was made to deliver ivermectin at 6 μg/kg and pyrantel at 5.0 mg/kg to each dog. Seven days after treatment the dogs were euthanased, necropsied, and examined for adult hookworms. At necropsy, no adult A braziliense was observed in any of the 6 treated dogs and all 6 dogs that had been left untreated were infected with adult A braziliense (range, 48 to 161). It was concluded that this combination product is 100% efficacious against adult A braziliense.  相似文献   
200.
In a 20‐yr‐old long‐term experiment, the impact of continuous application of organic manures and inorganic fertilizers on soil quality and the sustainability of finger millet production was conducted on two cropping systems: finger millet and finger millet–groundnut on an Alfisol of semi‐arid southern India. The study was conducted from 1992 to 2011 at the All India Coordinated Research Project for Dryland Agriculture, UAS, Bangalore, using a randomized block design. The treatments comprised of T1: control [no fertilizer and no farmyard manure (FYM) applied], T2: FYM 10 t/ha, T3: FYM 10 t/ha + 50% of recommended NPK (50:50:25 kg/ha), T4: FYM 10 t/ha + 100% of recommended NPK and T5: 100% recommended NPK. Comparison of long‐term yield data between treatments was used to calculate a ‘sustainability yield index’ (SYI), which was greatest for T4 (FYM 10 t/ha + 100% of recommended NPK), in both rotational (0.68) and monocropping (0.63) situations. Soil quality indices were determined using principal component analysis linear scoring functions. The key indicators which contributed to the soil quality index (SQI) under rotation were organic C; potentially available N; extractable P, K and S; exchangeable Ca and Mg; dehydrogenase activity and microbial biomass C and N. The largest SQI (7.29) was observed in T4 (FYM 10 t/ha + 100% NPK), and the smallest (3.70) SQI was for the control. Application of 10 t/ha FYM together with NPK (50:50:25 kg/ha) sustained a mean yield of 3884 kg/ha.  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