全文获取类型
收费全文 | 351篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
林业 | 18篇 |
农学 | 3篇 |
24篇 | |
综合类 | 25篇 |
农作物 | 3篇 |
水产渔业 | 17篇 |
畜牧兽医 | 258篇 |
园艺 | 8篇 |
植物保护 | 12篇 |
出版年
2024年 | 3篇 |
2023年 | 9篇 |
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 15篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 3篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 16篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 12篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 11篇 |
1993年 | 1篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有368条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
106.
Hannah E. Wong John M. Cullen Marta Vil-Gonzlez Rachel Pittaway Valeer J. Desmet Tammy D. Gillian 《Journal of veterinary diagnostic investigation》2023,35(2):196
Hepatic ciliated foregut remnants or cysts are congenital abnormalities resulting from retention of embryonic ciliated foregut within the liver. These structures are rarely reported in the human medical literature and have not been reported in the veterinary literature previously, to our knowledge. We describe here a case of an 8-wk-old male French Bulldog with a congenital patent hepatic ciliated foregut remnant resulting in an umbilicobiliary sinus tract. The dog also had concurrent gallbladder agenesis. The patient had yellow fluid discharging from the umbilicus, mimicking a patent urachus. Surgical exploration, removal, and histology provided a conclusive diagnosis of a hepatic foregut remnant and therapeutic resolution of the clinical signs. The histologic appearance of a hepatic foregut remnant is classical, namely a duct composed of 4 layers: an inner ciliated epithelial lining, loose connective tissue, smooth muscle, and a fibrous capsule. 相似文献
107.
H W Hannah 《Journal of the American Veterinary Medical Association》1985,187(11):1105-1106
108.
109.
110.
Monitoring of water resources for pesticide residues is often needed to ensure that pesticide use does not adversely impact the quality of public water supplies or the environment. In many rural areas and throughout much of the developing world, monitoring is often constrained by lack of testing facilities; thus, collection of samples and shipment to centralized laboratories for analysis is required. The portability, ease of use, and potential to enhance analyte stability make solid-phase extraction (SPE) an attractive technique for handling water samples prior to their shipment. We describe performance of an SPE method targeting a structurally diverse mixture of 25 current-use pesticides and two common degradates in samples of raw and filtered drinking water collected in Greater Cairo, Egypt. SPE was completed in a field laboratory in Egypt, and cartridges were shipped to the United States for elution and high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis. Quantitative and reproducible recovery of 23 of 27 compounds (average = 96%; percent relative standard deviation = 21%) from matrix spikes (1 microg L-1 per component) prepared in the field and from deionized water fortified similarly in the analytical laboratory was obtained. Concurrent analysis of unspiked samples identified four parent compounds and one degradate in drinking water samples. No significant differences were observed between raw and filtered samples. Residue levels in all cases were below drinking water and "harm to aquatic-life" thresholds, indicating that human and ecological risks of pesticide contamination were relatively small; however, the study was limited in scale and scope. Further monitoring is needed to define spatial and temporal variation in residue concentrations. The study has demonstrated the feasibility of performing studies of this type using SPE to extract and preserve samples in the field. The approach should be broadly applicable in many settings. 相似文献