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   442篇
  免费   42篇
林业   27篇
农学   3篇
基础科学   1篇
  32篇
综合类   63篇
农作物   5篇
水产渔业   45篇
畜牧兽医   278篇
园艺   5篇
植物保护   25篇
  2023年   6篇
  2021年   7篇
  2020年   16篇
  2019年   14篇
  2018年   13篇
  2017年   12篇
  2016年   11篇
  2015年   6篇
  2014年   10篇
  2013年   20篇
  2012年   18篇
  2011年   17篇
  2010年   13篇
  2009年   7篇
  2008年   21篇
  2007年   12篇
  2006年   16篇
  2005年   17篇
  2004年   15篇
  2003年   18篇
  2002年   14篇
  2001年   21篇
  2000年   8篇
  1999年   10篇
  1994年   5篇
  1993年   6篇
  1992年   10篇
  1991年   11篇
  1990年   8篇
  1989年   9篇
  1988年   7篇
  1987年   7篇
  1985年   5篇
  1984年   3篇
  1982年   3篇
  1981年   5篇
  1980年   5篇
  1979年   11篇
  1978年   5篇
  1977年   3篇
  1976年   4篇
  1974年   3篇
  1973年   5篇
  1972年   4篇
  1971年   3篇
  1970年   5篇
  1969年   3篇
  1967年   4篇
  1960年   2篇
  1958年   3篇
排序方式: 共有484条查询结果,搜索用时 31 毫秒
121.
Cetirizine hydrochloride was administered orally at 5 mg/cat, q24h, to 32 cats with allergic skin disease. Pruritus was reduced in 41% (13/32) of the cats. The antipruritic effect was repeatable and sustainable. There was no significant association between patient age, disease severity, or cutaneous reaction pattern and improvement during cetirizine administration. No adverse side effects were reported.  相似文献   
122.
AIM: To assess the degree of interference with bovine tuberculin testing in farmed red deer that vaccination of young deer with an oil-adjuvanted vs aqueous formulation of live attenuated Mycobacterium paratuberculosis Strain 316F vaccines would be likely to cause, and to compare immunological responses between vaccine formulations. METHODS: Five-month-old red deer (n = 45) were randomly allocated to three treatment groups of 15 animals, which received either no vaccine, a single 2-ml dose of an oil-adjuvanted formulation or two 2-ml doses, 6 weeks apart, of an aqueous formulation of live attenuated M. paratuberculosis Strain 316F vaccine injected subcutaneously (S/C) in the neck (Control, Oil-adjuvant Ptb, and Aqueous Ptb groups, respectively). Injection- site reactions were described and measured on Weeks 3, 6 and 9. Animals were weighed and lymphocyte transformation tests (LTT) and antibody enzyme-linked immunosorbent assays (ELISA) using avian, bovine and Johnin tuberculin were conducted on blood samples collected at Weeks 0, 6, 12, 15, 24, 27, 36 and 39. A bovine mid-cervical skin test (MCT) was applied at Week 12, and comparative cervical skin tests (CCTs) at Weeks 24 and 36. At Week 42, the animals were slaughtered at a commercial deer slaughter premises and subjected to rigorous meat inspection. RESULTS: Two animals were eliminated at the start of the trial due to a positive cross-reaction with bovine tuberculin in the initial LTT. Almost all animals reacted to the MCT at Week 12, with mean skin thicknesses of 3.9, 2.9 and 1.0 mm for the Oil-adjuvant Ptb, Aqueous Ptb and Control groups, respectively. When the CCT was conducted at Week 24, 2/15 Oil-adjuvant Ptb, 2/14 Aqueous Ptb and 1/14 Control animals were classified as CCT-positive to bovine tuberculin. By Week 36, all animals were CCT-negative. The Oil-adjuvant Ptb vaccination resulted in high persistent levels of antibody that reacted with bovine tuberculin, compared with negligible levels in the Aqueous Ptb group. Overall, a single dose of the Oil-adjuvant Ptb vaccine in deer stimulated a vigorous, cross-reactive immune response, evidenced by high LTT, skin-test and antibody reactions to bovine tuberculin, with both cell-mediated and humoral characteristics. By comparison, two doses of the Aqueous Ptb vaccine produced less cross-reactivity and a bias towards a cell-mediated response. The Oil-adjuvant Ptb vaccine resulted in moderate injection site lesions that were quite persistent, whereas the Aqueous Ptb vaccine resulted in smaller nodules that regressed more quickly. CONCLUSIONS: Vaccination of farmed deer with an oil-adjuvanted Johne's vaccine has the potential to cause significant interference with routine tuberculin skin testing. The cross-reactivity should decline with time and the CCT should be able to clear MCT-positives, but there is a risk of false-positives to the blood test for tuberculosis (BTB), due to high persistent levels of antibody. The CCT could be used as a primary skin test in vaccinated deer on some farms. The Aqueous Ptb caused fewer problems with skin testing and produced significantly less bovine antibody than the Oil-adjuvant Ptb, but stimulated persistent cell-mediated immune responses that may provide some protection against Johne's disease.  相似文献   
123.
The prevalence of Escherichia coli O157 was determined in 10662 fecal samples, 2130 water and 1132 water tank-sediment samples collected during the summer months in 2001 from 711 pens in 73 feedlots located in Kansas, Nebraska, Texas, or Oklahoma, USA. Overall, 10.2% of fecal samples were positive for E. coli O157, with 52% of the pens and 95.9% of the feedlots having at least one positive fecal sample. There were no differences among states or months in the fecal prevalences. Water or water tank-sediment was positive in 13.1% of the water tanks, and 60.3% of feedlots had at least one positive tank. Cattle were more likely to be shedding E. coli O157 in pens with positive water tanks, and water was more likely to be positive when E. coli O157 was detected in the sediment.  相似文献   
124.
OBJECTIVE: To evaluate a canine D-dimer point-of-care (cD-d POC) test kit for use in healthy dogs and dogs with disseminated intravascular coagulation (DIC), thromboembolic disease (TED), and hemorrhage. ANIMALS: 12 healthy dogs, 18 dogs with DIC, 23 dogs with TED (19 acute and 4 chronic), and 18 dogs with hemorrhage. PROCEDURE: The cD-d POC, canine D-dimer ELISA (cD-d ELISA), human D-dimer latex agglutination (hD-d LA), and fibrin degradation product (FDP) tests were performed on citrated plasma. RESULTS: All healthy dogs had negative cD-d POC test results and mean cD-d ELISA value of 0.2 U/mL. All dogs with DIC had positive cD-d POC test results and mean cD-d ELISA value of 44 U/mL. Dogs with acuteTED had a mean cD-d ELISA value of 34 U/mL, and 17 of 19 had positive cD-d POC test results. Mean cD-d ELISA value in dogs with hemorrhage was 14 units/mL, and 15 of 18 had positive cD-d POC test results. The cD-d ELISA values in dogs with hemorrhage were significantly higher than those of healthy dogs but lower than those of dogs with DIC and acute TED. The cD-d POC, cD-d ELISA, and hD-d LA tests were comparable in differentiating healthy dogs from dogs with DIC, acute TED, or hemorrhage and appeared to be superior to measurement of FDPs. CONCLUSIONS AND CLINICAL RELEVANCE: The cD-d POC test kit can be quickly and easily used and reliably detects dogs with DIC or acute TED. Positive results may also be seen in dogs with internal hemorrhage.  相似文献   
125.
Limited nutritional information exists on diets of free-ranging orangutans, Pongo abelii and P. pygmaeus. Although they are classified as frugivores, the chemical composition of their diet and their gastrointestinal anatomy suggest that they rely on fiber fermentation for a substantial portion of energy. However, the extent to which they can ferment fiber is not known. Continuous culture systems, inoculated with orangutan fecal bacteria, were established to determine the fiber-digesting capacity of orangutan hindgut microflora. The cultures received one of four treatments: soybean hulls, ground corncobs, corn starch, or no food. Neither dry matter nor neutral detergent fiber digestibilities differed significantly among treatments. However, neutral detergent fiber digestibilities were high for both the soybean hull (88.4%) and ground corncob (86.1%) treatments, indicating that the microflora had a strong fibrolytic capability. To determine whether the same fiber-degrading capacity occurred in vivo, two adult orangutans and one juvenile were fed four gel-matrix diets containing soybean hulls, ground corncobs, or ground primate biscuits. Neutral detergent fiber concentrations (dry matter basis) of the gel matrices were 52.9% with soybean hulls, 46.8% and 63.7% with ground corncobs, and 31.3% with ground primate biscuits. A fifth diet consisted of primate biscuits with 27.3% neutral detergent fiber (dry matter basis) and was considered the baseline diet. Neutral detergent fiber digestibility (74.5%) was greatest (P < 0.05) for the soybean hull gel diet and least (57.5% and 45.0%, respectively; P < 0.05) for the 63.7% neutral detergent fiber (dry matter basis) corncob gel diet and the baseline primate biscuit diet. Total volatile fatty acid concentrations in orangutan feces were not significantly different among diets; however, molar proportions of acetic, propionic, and butyric acid differed (P < 0.05) among diets. The results from both studies indicated that orangutans are capable of extensive fiber fermentation.  相似文献   
126.
The objective of the present study was to compare the efficacy of a commercial limited-antigen diet (Eukanuba Veterinary Diets Response Formula FP/Canine, The Iams Company) with home-prepared diets in the diagnosis of adverse food reaction in dogs. The study was conducted in two phases. The first phase utilized 28 dogs fed a home-prepared diet to enable a diagnosis of adverse food reaction. Dogs diagnosed from this phase were entered into the second phase in which these dogs were fed the commercial limited-antigen diet. Owners of 10 of the 28 dogs quit Phase 1 before it could be completed, and one case was eliminated because extended treatment with steroids was required. Eight of the remaining 17 (47 %) dogs were diagnosed with an adverse food reaction. A reaction occurred in four of eight dogs fed the test diet in Phase 2. These results demonstrated the difficulties encountered by owners and veterinarians attempting to feed dogs home-prepared diets. In addition, the results of the study suggest that the occurrence of adverse reactions to fish could make it a less desirable ingredient as a limited antigenin canine diets.  相似文献   
127.
1. Feeding a diet supplemented with maize oil was found to elevate plasma oestradiol concentration in laying hens.

2. In a larger‐scale experiment, isoenergetic and isonitrogenous diets containing 10, 20, 40 or 60 g/kg supplemental maize oil, tallow, coconut oil or fish oil were fed for 5 weeks.

3. Egg weights showed very different responses to the different fats. The responses could be described by quadratic functions that all gave optimum responses with supplemental dietary fat concentrations of about 40 g/kg. Egg weight increased the most with maize oil and was decreased with fish oil at the highest inclusion rate.

4. Measurements of egg components showed a relatively larger increase in albumen weights with maize oil than with other fats.

5. Across treatments, mean plasma oestradiol concentrations were very highly correlated (r = 0.96) with the changes in egg weights over the experimental period.

6. It is concluded that oestrogen is important in controlling egg weight and that the effect of dietary fats in influencing egg weight is mediated by an effect of the fats on oestrogen metabolism.  相似文献   

128.
1. The relationships between plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) triglyceride concentrations at 3 and 7 weeks of age and body fat content at 7 weeks were studied in male and female broiler grandparent stock fed on diets containing about 25 or 90 g fat/kg.

2. Plasma VLDL plus LDL triglyceride concentrations were similar in males and females and only slightly higher in birds fed on the high‐fat diet. Concentrations at 3 weeks were similar to those at 7 weeks.

3. Body fat content was correlated more closely with plasma VLDL plus LDL triglyceride measured at 7 weeks than at 3 weeks.

4. Phenotypic correlations between body fat content and plasma VLDL plus LDL triglyceride concentrations at 7 weeks were 0.47 and 0.43 for males and females respectively fed on the high‐fat diet and 0.70 and 0.60 for males and females fed on the low‐fat diet.

5. Phenotypic correlations between body fat content and measurements with an abdominal caliper were 0.35 and 0.49 in birds fed on the high‐ and low‐fat diets respectively.

6. A possible procedure for selecting for leanness in broiler breeding programmes on the basis of measurements of plasma VLDL plus LDL triglycerides is discussed.  相似文献   

129.
130.
AIMS: To test the efficacy of a commercially available and an experimental vaccine against Johne's disease in young red deer (Cervus elaphus), using experimental challenge with live virulent Mycobacterium avium subsp paratuberculosis (M. ptb), measure injection-site reactions, and assess the effects of vaccination and challenge on results of subsequent skin tests and ancillary blood tests for bovine tuberculosis (Tb). METHODS: Ninety 6-8-week-old red deer fawns were randomly allocated to three equal groups of 30, and received either a 1-ml S/C injection of either a commercially available whole-cell killed vaccine with a mineral-oil adjuvant (COM), or a live attenuated M. ptb experimental vaccine with a lipid adjuvant (EXP), or were unvaccinated controls. Ten weeks later (Week 10), all 90 fawns received an oral challenge with approximately 10(8) cfu of a bovine strain of M. ptb daily for 4 days. The fawns were regularly weighed and monitored for clinical signs of Johne's disease, and regularly blood-sampled and tested for antibodies to M. ptb, using the Paralisa test, an IgG1 ELISA, and for antibodies to Mycobacterium bovis, using a similar test. A mid-cervical tuberculin skin test (MCT) was administered at Week 23, and comparative cervical skin tests (CCTs) were administered at Weeks 37 and 57. All animals were electively killed at Week 59, injection sites inspected, gastrointestinal tracts examined for gross lesions, and samples taken for culture and histopathology. RESULTS: There were no clinical cases of Johne's disease but, at slaughter, more gross lesions in intestinal lymph nodes were observed in Control (20%) than COM animals (0%; p<0.05). This latter group also had less severe histopathological lesions in samples of intestines and lymph nodes compared with the Control group (p<0.05), but not deer in the EXP group. Over 89% of deer in all three groups were shown by culture to be infected with M. ptb, while only 21-33% of faecal samples were culture-positive. Time to positive culture was longer for COM vs EXP and Control groups (p<0.01), reflecting fewer M. ptb organisms in samples from the ileocaecal valve (ICV) in that group. Almost all (>or=90%) deer reacted to the MCT at Week 23, and there were no significant differences between groups. One or two deer in each group were classified as Tb reactors to the CCT at Week 37, and none were classified as Tb reactors to the CCT at Week 57. At the time of challenge, over 50% of deer in the COM group were classified as positive (9/28) or suspicious (7/28) for M. ptb antibodies in the Paralisa test, one animal in the EXP group was classified as suspicious, and all the Controls were negative. From Week 23 to the end of the trial, 25/28 (89%) deer in the COM group were Paralisa-positive or -suspicious. The proportion of animals in the EXP and Control groups that were Paralisa-positive peaked at Week 39 (60% and 55%, respectively). The majority of deer in the COM group had significant levels of antibody to M. bovis 10 weeks after vaccination, while the proportion of M. bovis-antibody positive Control deer rose gradually throughout the trial, reaching 23/30 (77%) at slaughter. Injection-site lesions in COM deer ranged from 10-38 mm in diameter 4 weeks after vaccination, and then resolved. Minimal injection-site lesions were observed in EXP deer. At slaughter, 14 months after vaccination, 19/28 deer in the COM group had 5-15-mm nodules that were easily trimmed from the carcass. CONCLUSIONS: The experimental challenge with M. ptb produced subclinical Johne's disease in the majority of deer, but did not cause any clinical disease. The number and severity of gross and microscopic lesions was significantly reduced in the COM compared with Control and EXP groups; vaccination of the EXP group did not appear to give significant protection. Deer vaccinated with the commercial vaccine are likely to give a false-positive reaction to the MCT but should have an avian reaction to the CCT, if it is carried out >12 months after vaccination. Most of the deer vaccinated with the commercial vaccine produced significant levels of antibodies against both M. ptb and M. bovis, which interfered with ancillary Tb tests. If this vaccine or similar oil-based vaccines are used on deer farms in the future, it may be advisable to only vaccinate animals destined for slaughter, that would not need to be Tb-tested, but would be 'works-monitored' for evidence of Tb instead.  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