全文获取类型
收费全文 | 421篇 |
免费 | 18篇 |
专业分类
林业 | 16篇 |
农学 | 16篇 |
基础科学 | 6篇 |
53篇 | |
综合类 | 33篇 |
农作物 | 71篇 |
水产渔业 | 14篇 |
畜牧兽医 | 184篇 |
园艺 | 12篇 |
植物保护 | 34篇 |
出版年
2023年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 25篇 |
2012年 | 15篇 |
2011年 | 39篇 |
2010年 | 18篇 |
2009年 | 14篇 |
2008年 | 19篇 |
2007年 | 21篇 |
2006年 | 24篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 4篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1994年 | 6篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1986年 | 3篇 |
1984年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1971年 | 8篇 |
1970年 | 7篇 |
1964年 | 2篇 |
1962年 | 2篇 |
1958年 | 4篇 |
1957年 | 2篇 |
1953年 | 3篇 |
1948年 | 2篇 |
1939年 | 5篇 |
1933年 | 4篇 |
排序方式: 共有439条查询结果,搜索用时 367 毫秒
101.
102.
Hugh F. Evans 《Integrated Pest Management Reviews》1999,4(4):295-299
The minor position of microbial insecticides within the global pesticide market can be attributed to a number of causes, including high cost of production, high specificity, poor application technology, poor persistence and slow speed of kill. These aspects are discussed in relation to the potential for use of microbial insecticides against forest pests. Many of the constraints are not limiting in forestry and some of the ways in which they can be overcome are discussed, including the concept of a better appreciation of the ecological context. This approach encompasses knowledge of the behaviour of the target host species, both for improved targeting and for maximum exploitation of secondary inoculum. These, and other aspects are brought together in discussing the future for microbial insecticides in forest pest management. 相似文献
103.
104.
105.
106.
107.
108.
109.
Andrea C Bourque Gary Conboy Lisa M Miller Hugh Whitney 《Journal of veterinary diagnostic investigation》2008,20(1):11-20
Fifty-six dogs from St. John's, Newfoundland, Canada, were evaluated for Angiostrongylus vasorum infection. Small numbers of nematodes were found within pulmonary arteries of 6 dogs. Larvae were identified in fecal samples in 2 of 6 dogs. All 6 dogs had multifocal granulomatous pneumonia and sometimes foci of chronic thrombosis, which varied from very mild to severe. One dog had extensive pulmonary lesions resulting in cor pulmonale. Right heart failure was characterized by right ventricular hypertrophy, hepatic congestion, ascites, and hydrothorax. Microscopically, in most cases, eggs, larvae, and sometimes intravascular adults, were present within lung tissue sections. Small foci of granulomatous inflammation with and without larvae were present in kidney and brain in 4 dogs. An additional dog, diagnosed antemortem with angiostrongylosis via fecal examination, was also examined. Pathological findings consisted of severe pyogranulomatous interstitial pneumonia with myriad eggs, larvae, and numerous intravascular pulmonary adult nematodes with extensive arterial thrombosis. Five hundred and seventy-two adult worms were removed from pulmonary arteries. Foci of granulomatous inflammation, often associated with larvae and/or eggs, were present in tracheobronchial lymph nodes, adrenal gland, brain, and kidneys. Severe seizuring noted antemortem was attributed to several large, discrete areas of acute hemorrhagic infarction within the cerebrum and cerebellum. Natural A. vasorum infection in domestic dogs in eastern Newfoundland causes lung pathology of variable severity, which in some cases, may progress to cor pulmonale and which may be associated with extrapulmonary lesions and clinical signs. 相似文献
110.
Marco Tulio C. Almeida Josimari R. Paschoaloto Henrique L. Perez Vanessa B. Carvalho Antonio C. Homem Junior Vanessa R. Favaro Hugh T. Blair Jane M. B. Ezequiel 《Journal of animal physiology and animal nutrition》2019,103(4):988-996
The effects of adding crude glycerine with sodium monensin or essential oils to beef cattle diets on the intake, degradability of DM and nutrients, rumen concentration of volatile fatty acids (VFA) and in vitro gas production were evaluated. Five ruminally cannulated Nellore steers were randomly assigned to a 5 × 5 Latin square design. The treatments were as follows: CONT, without crude glycerine and additives; EO, with essential oils and without crude glycerine; MON, with sodium monensin and without crude glycerine; EOG, with essential oils and crude glycerine; MONG, with sodium monensin and crude glycerine. Treatments with essential oil and sodium monensin increased the NDF and STC intake and the DM degradability. When crude glycerine was combined with either sodium monensin or essential oil, there was a reduction in DM, NDF and STC intake and an increase in DM and CP degradability of the diets. The adding crude glycerine to essential oil diets reduced the CH4 production. Sodium monensin treatments reduced DM and NDF intake and the production of total gas, CH4, total VFA and acetic acid concentration. In conclusion, the adding crude glycerine (200 g/kg DM) with either sodium monensin (0.03 g/kg DM) or essential oil (0.5 g/kg DM) can be utilized in diets for Nellore cattle without causing detrimental effects on feed intake and improving the DM degradability. 相似文献