全文获取类型
收费全文 | 616篇 |
免费 | 33篇 |
专业分类
林业 | 15篇 |
农学 | 18篇 |
基础科学 | 3篇 |
104篇 | |
综合类 | 90篇 |
农作物 | 60篇 |
水产渔业 | 54篇 |
畜牧兽医 | 258篇 |
园艺 | 12篇 |
植物保护 | 35篇 |
出版年
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 19篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 20篇 |
2015年 | 14篇 |
2014年 | 15篇 |
2013年 | 37篇 |
2012年 | 36篇 |
2011年 | 55篇 |
2010年 | 24篇 |
2009年 | 20篇 |
2008年 | 26篇 |
2007年 | 34篇 |
2006年 | 37篇 |
2005年 | 26篇 |
2004年 | 35篇 |
2003年 | 24篇 |
2002年 | 22篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1966年 | 3篇 |
排序方式: 共有649条查询结果,搜索用时 31 毫秒
91.
Georgios Theodoropoulos Helen Theodoropoulou Georgios Skopelitis Konstantinos Benardis 《Preventive veterinary medicine》2009,89(3-4):277-281
Commission Regulation (EC) No. 2075/2005 of 5 December 2005 lays down detailed conditions for Trichinella-free farms. The objectives of the present study were: (1) to assess the current state of swine farms in Greece in relation to the risk of exposure of pigs to Trichinella as a first step towards certification of Trichinella-free farms in Greece and (2) to identify a profile and characteristics of swine farms and farmers which can be used to formulate appropriate measures to promote good production practices for reducing risk of exposure of pigs to Trichinella. A total of 70 swine farms were inspected using audit components similar to those used by the U.S. Trichinae Certification Programme. Only four farms (6%) complied with all the criteria used for assessing the good production practices for reducing risk of exposure of pigs to Trichinella. A common characteristic of these four farms was that they had a large size (>300 sows) and produced their own feed. The most common issues among the farms that did not meet audit criteria in the present study were related to proper rodent control and accessibility of other animals in the feed storage area and the facility. In addition, the predominant significant differentiating characteristic for the farms not meeting the criteria was their small (<150 sows) size, while for the farmers it was their low educational level. These characteristics, which are linked to poor infrastructure and reluctance for improvements, respectively, will be difficulties that must be dealt with in the promotion of good production practices for Trichinella-free farms in Greece. 相似文献
92.
93.
Corrigan RL Waldner C Epp T Wright J Whitehead SM Bangura H Young E Townsend HG 《Preventive veterinary medicine》2006,76(3-4):263-272
In 2003, an outbreak of West Nile virus (WNV) occurred in Saskatchewan, Canada from July to September. One-hundred thirty-three horse cases and 947 human cases were recorded and data were analyzed retrospectively for evidence of clustering to determine if clinical infection in the horse population could be used to estimate human risk of infection with WNV. Kulldorff's scan statistic was used to identify spatial-temporal clusters in both the human and horse cases. In most areas, human clusters were not preceded by horse clusters. In one area, a significant cluster of horse cases preceded human cases by 1 week; however, 1 week does not provide sufficient time for human-health authorities to act and provide advance warning for the public. 相似文献
94.
Fish Physiology and Biochemistry - Sharks are not only threatened, but also have a low fecundity as they are being overfished. The shark family, Sphyrnidae, consists of nine species of which three... 相似文献
95.
96.
Positive PCR alone should not be considered sufficient to establish Dirofilaria repens as the cause of subcutaneous nodular lesions in the absence of a clear cytologic picture
下载免费PDF全文
![点击此处可从《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
97.
Xiuzhen Shi Hang-Wei Hu Kevin Kelly Deli Chen Ji-Zheng He Helen Suter 《Journal of Soils and Sediments》2017,17(4):974-984
Purpose
The nitrification inhibitor 3,4-dimethylpyrazol-phosphate (DMPP) and the urease inhibitor N-(n-butyl) thiophosphoric triamide (nBTPT) can mitigate N losses through reducing nitrification and ammonia volatilization, respectively. However, the impact of repeated applications of these inhibitors on nitrogen cycling microorganisms is not well documented. This study aimed to investigate the changes in the abundance and community structure of the functional microorganisms involved in nitrification and denitrification in Australian pasture soils after repeated applications of DMPP and nBTPT.Materials and methods
Soil was collected in autumn and spring, 2014 from two pasture sites where control, urea, urea ammonium nitrate, and urea-coated inhibitors had been repeatedly applied over 2 year. Soil samples were analyzed to determine the potential nitrification rates (PNRs), the abundances of amoA, narG, nirK and bacterial 16S rRNA genes, and the community structure of ammonia oxidizers.Results and discussion
Two years of urea application resulted in a significantly lower soil pH at Terang and a significant decrease in total bacterial 16S rRNA gene abundance at Glenormiston and led to significantly higher PNRs and abundances of ammonia oxidizers compared to the control. Amendment with either DMPP or nBTPT significantly decreased PNRs and the abundance of amoA and narG genes. However, there was no fertilizer- or inhibitor-induced change in the community structure of ammonia oxidizers.Conclusions
These results suggest that there were inhibitory effects of DMPP and nBTPT on the functional groups mediating nitrification and denitrification, while no significant impact on the community structure of ammonia oxidizers was observed. The application of nitrification or urease inhibitor appears to be an effective approach targeting specific microbial groups with minimal effects on soil pH and the total bacterial abundance.98.
Folate Polyglutamylation is Required for Rice Seed Development 总被引:1,自引:0,他引:1
99.