全文获取类型
收费全文 | 1257篇 |
免费 | 38篇 |
专业分类
林业 | 31篇 |
农学 | 20篇 |
基础科学 | 9篇 |
103篇 | |
综合类 | 310篇 |
农作物 | 36篇 |
水产渔业 | 97篇 |
畜牧兽医 | 583篇 |
园艺 | 13篇 |
植物保护 | 93篇 |
出版年
2020年 | 17篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2016年 | 15篇 |
2014年 | 20篇 |
2013年 | 46篇 |
2012年 | 37篇 |
2011年 | 47篇 |
2010年 | 31篇 |
2009年 | 25篇 |
2008年 | 52篇 |
2007年 | 54篇 |
2006年 | 56篇 |
2005年 | 43篇 |
2004年 | 49篇 |
2003年 | 33篇 |
2002年 | 21篇 |
2001年 | 29篇 |
2000年 | 30篇 |
1999年 | 20篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 13篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 21篇 |
1991年 | 41篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 38篇 |
1987年 | 24篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1980年 | 13篇 |
1979年 | 19篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1975年 | 8篇 |
1974年 | 22篇 |
1973年 | 20篇 |
1972年 | 15篇 |
1971年 | 13篇 |
1970年 | 14篇 |
1969年 | 18篇 |
1968年 | 10篇 |
1967年 | 12篇 |
1966年 | 10篇 |
排序方式: 共有1295条查询结果,搜索用时 15 毫秒
41.
Ana Afonso Jose Cortinas Abrahantes Franz Conraths Anouk Veldhuis Armin Elbers Helen Roberts Yves Van der Stede Estelle Méroc Kristel Gache Jane Richardson 《Preventive veterinary medicine》2014
During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006–2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases. 相似文献
42.
An adult female neutered crossbred dog was referred in respiratory distress. Thoracic radiographs revealed tracheal narrowing with a soft tissue opacity dorsal to the trachea, near the thoracic inlet, and a patchy interstitial pulmonary infiltrate. The tracheal narrowing was thought to be due to a combination of intraluminal haemorrhage and mediastinal haemorrhage resulting from a coagulopathy caused by anticoagulant rodenticide intoxication. Treatment included supportive care and administration of vitamin K1, and the dog showed a complete resolution of the clinical signs. 相似文献
43.
A case of primary intraocular melanoma in an alpaca is reported. This patient also presented with a mild normocytic, normochromic anemia and hypoproteinemia. These can be markers of an immunodeficiency syndrome associated with llamas. Although this patient did not appear to have clinical signs of this syndrome, its presence needed to be ruled out as animals affected with this syndrome are subject to recurrent severe debilitating diseases and death. To our knowledge, intraocular melanoma has not been previously reported in an alpaca. 相似文献
44.
45.
Two experiments were conducted to evaluate two carrier proteins and nine adjuvants in promoting antibody production in heifers immunized against LH. The anti-LH antibody response was evaluated in heifers immunized against LH conjugated to either ovalbumin or keyhole limpet hemocyanin (KLH) (Exp. 1). In Exp. 2, an LH-ovalbumin conjugate was used to evaluate effectiveness of nine different adjuvants in antibody production. Weekly blood samples were collected from all heifers throughout the 23-wk study to determine LH antibody binding activity. In Exp. 1, heifers immunized with the LH-ovalbumin (LH-oval) conjugate had greater LH antibody binding activities (P less than .001) than those immunized with the LH-KLH conjugate. In Exp. 2, nine groups of heifers were immunized with LH-oval suspended in one of nine adjuvants; a 10th group was immunized against ovalbumin alone (control). Only adjuvants that contained at least 40% oil resulted in LH antibody binding activity that differed (P less than .01) from control. These results show that ovalbumin was a superior carrier protein to KLH in enhancing antibody production; adjuvants with greater than 50% oil were superior to those with less oil in promoting LH antibody production. 相似文献
46.
The effect of meal size and frequency on plasma volume, plasma aldosterone concentration and urinary Na and K clearances was determined in ponies. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen, ie, 12 equal portions fed at 2-hour intervals, or as single large feedings, ie, half the ration fed every 12 hours at 0800 and 2000 hours. Only the effect of the single morning feeding was studied, using the latter regimen. Serial measurements of plasma volume were made by use of an indicator-dilution technique and indocyanine green (0.15 mg/kg of body weight, IV) that allowed repeated determinations at 2-hour intervals. Ingestion of the single large meal caused a 15% decrease in plasma volume by the end of a 1-hour feeding period. Feeding hypovolemia was confirmed by a coincident increase in plasma protein concentration (12%) and, in separate experiments, by analysis of postfeeding changes in the elimination of Evans blue dye. Plasma aldosterone concentration was significantly (P less than 0.05) increased from 2 to 5 hours after feeding. Urinary Na clearance decreased in response to feeding and remained lower than the prefeeding value until 9 hours after feeding. Urinary K clearance increased from prefeeding and reached a peak value between 5 and 7 hours after feeding. Creatinine clearance was unaffected. In contrast, the aforementioned variables were unchanged during the multiple regimen. Results indicate that ingestion of a large concentrate meal by ponies causes periprandial hypovolemia, activation of the renin-angiotensin-aldosterone system, and a subsequent antinatriuresis-kaliuresis that lasts for several hours. 相似文献
47.
M G Davidson E B Breitschwerdt M P Nasisse S M Roberts 《Journal of the American Veterinary Medical Association》1989,194(6):777-781
Dogs were examined ophthalmoscopically to determine the prevalence and type of ocular lesions associated with naturally acquired Rocky Mountain spotted fever (RMSF). In a consecutive series of 11 dogs with serologically confirmed RMSF, 9 had ocular involvement reflecting various degrees of vascular damage, including subconjunctival hemorrhage, hyphema, anterior uveitis, iris stromal hemorrhage, retinal petechiae, and focal areas of retinal edema and perivascular inflammatory cell infiltrate. The ophthalmic lesions generally were mild, and most resolved without complication after systemic administration of appropriate antibiotics. The high prevalence of ocular lesions in these dogs suggested that critical ophthalmologic evaluation is a useful diagnostic tool for the early detection and management of RMSF in dogs. 相似文献
48.
49.
J. A. Roberts 《Australian veterinary journal》1972,48(9):514-514
50.
Effects of hyperbaric oxygen therapy on uncomplicated incisional and open wound healing in dogs 下载免费PDF全文