全文获取类型
收费全文 | 8724篇 |
免费 | 415篇 |
国内免费 | 57篇 |
专业分类
林业 | 1353篇 |
农学 | 298篇 |
基础科学 | 70篇 |
1451篇 | |
综合类 | 788篇 |
农作物 | 288篇 |
水产渔业 | 394篇 |
畜牧兽医 | 3755篇 |
园艺 | 229篇 |
植物保护 | 570篇 |
出版年
2022年 | 76篇 |
2021年 | 109篇 |
2020年 | 138篇 |
2019年 | 81篇 |
2018年 | 221篇 |
2017年 | 188篇 |
2016年 | 217篇 |
2015年 | 192篇 |
2014年 | 176篇 |
2013年 | 454篇 |
2012年 | 421篇 |
2011年 | 391篇 |
2010年 | 249篇 |
2009年 | 170篇 |
2008年 | 335篇 |
2007年 | 384篇 |
2006年 | 345篇 |
2005年 | 299篇 |
2004年 | 268篇 |
2003年 | 263篇 |
2002年 | 247篇 |
2001年 | 151篇 |
2000年 | 162篇 |
1999年 | 129篇 |
1995年 | 59篇 |
1992年 | 101篇 |
1991年 | 113篇 |
1990年 | 136篇 |
1989年 | 147篇 |
1988年 | 124篇 |
1987年 | 104篇 |
1986年 | 115篇 |
1985年 | 109篇 |
1984年 | 99篇 |
1983年 | 79篇 |
1982年 | 60篇 |
1979年 | 106篇 |
1978年 | 79篇 |
1977年 | 73篇 |
1976年 | 58篇 |
1975年 | 74篇 |
1974年 | 89篇 |
1973年 | 106篇 |
1972年 | 75篇 |
1971年 | 96篇 |
1970年 | 85篇 |
1969年 | 91篇 |
1968年 | 74篇 |
1967年 | 71篇 |
1965年 | 60篇 |
排序方式: 共有9196条查询结果,搜索用时 15 毫秒
991.
992.
993.
The neonatal depression of puppies, developed by C-section, can be treated effectively by the application of 0.1-0.2 ml Narcanti respectively Narcanti Neonatal (Naloxon) right after development. The technique of the intravenous injection in newborn puppies is simple and easy to learn. 相似文献
994.
995.
Relationships between the Quality of Dietary Proteins and the Functional State of the Adrenal Cortex. (5) Content of Corticosterone and Cortisol in the Liver and in the Mucosa of the Small Intestine of Rats Fed Proteins of Varying Quality (Estimation of the Binding Capacity for Corticosteroids). Growing male Wistar rats were used to investigate in which way the quality of dietary proteins (maize gluten and maize gluten supplemented with amino acids) influenced the content of corticosteroids in the liver and in the mucosa of the small intestine of untreated rats (N), adrenalectomized animals (AE) and animals treated with corticosteroids (N + S). In AE animals the content of corticosteroids in the tissues was very low. In N + S animals of both dietary groups the mucosa of the small intestine contained more corticosteroids than the liver; the content of corticosteroids in the mucosa, however, was also found to vary in dependence upon the diet fed. The mucosa of N + S animals receiving dietary proteins of high quality contained more corticosteroids; this indicates a higher binding capacity of the mucosa for corticosteroids. 相似文献
996.
997.
998.
Three pigs, of 34 kg live weight, were each fitted with re-entrant cannulas both in the duodenum and terminal ileum and catheters in the jugular vein and in the carotid artery. Pigs received a diet based on wheat and dried skimmed milk in equal amounts at 12 h intervals. During the preliminary period the digesta flowing from both duodenal and ileal cannulas were collected over 12 h after feeding on two consecutive days and half of them were reintroduced into the gut and half were stored at -20 degrees C. During the experimental period 15N-urea was infused into the jugular vein for 12 hours starting with the morning meal. Total amount of urea infused was 5 g containing 1.22 g 15N-excess. The digesta from both proximal duodenal and ileal cannulas were collected and stored, while the digesta from the preliminary period were reintroduced into the respective distal cannulas. Blood samples were taken at different time of infusion. At the end of infusion period the animals were sacrificed and samples of the contents of the digestive tract and tissues were taken. Urea flux calculated according to atom-% 15N-excess of urea N in plasma was 1.23 to 2.37 g/kg body weight/day. In the duodenal digesta 94.5 +/- 0.2 and in ileal digesta 57.1 +/- 7.39 per cent of 15N were in the TCA soluble fraction. The total amount of 15N in the duodenal digesta was 1.7 to 6.3 times greater than in the ileal digesta. Only small amount of 15N was found in the caecum and almost none in the contents of colon and rectum. It is concluded that urea is secreted into all parts of the digestive tract, the main sites of urea secretion being pancreatic juice and/or bile as well as the small intestine. The total amount of urea secreted is assumed to be similar to the daily urea excretion. 相似文献
999.
1000.