全文获取类型
| 收费全文 | 3406篇 |
| 免费 | 139篇 |
| 国内免费 | 3篇 |
专业分类
| 林业 | 211篇 |
| 农学 | 86篇 |
| 基础科学 | 21篇 |
| 618篇 | |
| 综合类 | 490篇 |
| 农作物 | 173篇 |
| 水产渔业 | 286篇 |
| 畜牧兽医 | 1352篇 |
| 园艺 | 104篇 |
| 植物保护 | 207篇 |
出版年
| 2023年 | 20篇 |
| 2022年 | 17篇 |
| 2021年 | 61篇 |
| 2020年 | 64篇 |
| 2019年 | 69篇 |
| 2018年 | 62篇 |
| 2017年 | 68篇 |
| 2016年 | 84篇 |
| 2015年 | 48篇 |
| 2014年 | 86篇 |
| 2013年 | 127篇 |
| 2012年 | 147篇 |
| 2011年 | 235篇 |
| 2010年 | 108篇 |
| 2009年 | 98篇 |
| 2008年 | 188篇 |
| 2007年 | 210篇 |
| 2006年 | 222篇 |
| 2005年 | 204篇 |
| 2004年 | 209篇 |
| 2003年 | 196篇 |
| 2002年 | 191篇 |
| 2001年 | 41篇 |
| 2000年 | 39篇 |
| 1999年 | 40篇 |
| 1998年 | 51篇 |
| 1997年 | 50篇 |
| 1996年 | 44篇 |
| 1995年 | 37篇 |
| 1994年 | 35篇 |
| 1993年 | 29篇 |
| 1992年 | 32篇 |
| 1991年 | 29篇 |
| 1990年 | 33篇 |
| 1989年 | 29篇 |
| 1988年 | 21篇 |
| 1987年 | 20篇 |
| 1986年 | 16篇 |
| 1985年 | 27篇 |
| 1984年 | 19篇 |
| 1983年 | 25篇 |
| 1982年 | 23篇 |
| 1981年 | 21篇 |
| 1980年 | 19篇 |
| 1978年 | 18篇 |
| 1977年 | 10篇 |
| 1975年 | 16篇 |
| 1974年 | 16篇 |
| 1967年 | 8篇 |
| 1966年 | 7篇 |
排序方式： 共有3548条查询结果，搜索用时 15 毫秒
951.
Secondary sewage effluent has been used as a nutrient source for the outdoor mass culture of marine phytoplankton that serve as food for bivalve molluscs in a combined tertiary sewage treatment-aquaculture system. Using a daily harvest rate of 50%, yield in algae ranged from one to five grams carbon/m2/day and averaged 2.6 over the four-month experimental period. 相似文献
952.
953.
954.
A stable adult animal model is needed to mimic as closely as possible the conditions which will exist when a permanent total cardiac prosthesis is placed in a human. Such a model presently under investigation is the adult Nubian goat. One of the studies utilized to assess the thoracic anatomy of this animal was computed tomography. The resulting computed tomograms provide a reference for the normal cross-sectional thoracic anatomy of the adult goat 相似文献
955.
Larval Distribution and Histopathology of Experimental Strongyloides ransomi Infection in Young Swine 
下载免费PDF全文
下载免费PDF全文 Necropsy at various intervals of three week old pigs following experimental infection with larvae of Strongyloides ransomi showed distribution of the larvae through the body during the first 24 hours. Quiescent larvae at the 24 hour necropsy, as indicated by higher recovery before and after this period may be an indication of physiological changes preceding a moult. Whether or not a moult occurs in the lung prior to migration of the larvae to the intestine has not been determined. At the 72 hour necropsy, larvae were largely confined to the lung and juvenile worms were beginning to appear in the small intestine. Migration to the small intestine was completed by the 96 hour necropsy. Lesions were observed in the skin and lungs up to the 96 hour necropsy, and lymphocytic accumulations were observed in the skin and lungs to this point and lymphocytic accumulations were observed in the liver to the 72 hour necropsy. At 28 days post-application lung lesions were still evident and the duodenum and jejunum were heavily parasitized.
Egg passage began on the sixth day post-application and peaked on the 12th day.
相似文献956.
William J. Donawick 《Veterinary surgery : VS》1975,4(1):39-43
The horse with an abdominal crisis caused by acute gastro-intestinal tract obstruction develops hypovolemia, hemoconcentration, electrolyte depletion, metabolic acidosis and shock. During preparation for operation, treatment with fluids, antibiotics and bicarbonate will impede metabolic imbalance. Stomach decompression may slow the passage of sodium, water and potassium to the gut lumen, reduce pain and minimize the risk of stomach rupture. Selected laboratory determinations and the monitoring of arterial and venous pressures will provide a measure of severity and serve as a guide to replacement therapy. In the post surgical period, vigilance must be directed towards potassium and bicarbonate imbalanc and adequate hydration. 相似文献
957.
958.
959.
960.
A sensitive, specific and convenient method for the determination of dichlorvos in air is described. The method involves the use of glass tubes containing potassium nitrate for trapping dichlorvos vapour from the air and flame-photometric gas chromatography for the determination of dichlorvos. The recovery of dichlorvos is 80% and the coefficient of variation for the method is 10%. The method gives results which compare favourably with those obtained by the Drechsel bottle procedure. In addition, the method requires only low sample volumes and can be applied to determine levels of dichlorvos in confined spaces. The sampling flow rate is not critical but storage of the sampling tubes below room temperature prior to analysis is necessary. 相似文献