全文获取类型
收费全文 | 224289篇 |
免费 | 12165篇 |
国内免费 | 445篇 |
专业分类
林业 | 10120篇 |
农学 | 7562篇 |
基础科学 | 1530篇 |
29945篇 | |
综合类 | 37828篇 |
农作物 | 9500篇 |
水产渔业 | 11650篇 |
畜牧兽医 | 109904篇 |
园艺 | 3454篇 |
植物保护 | 15406篇 |
出版年
2020年 | 1981篇 |
2019年 | 2343篇 |
2018年 | 4000篇 |
2017年 | 4452篇 |
2016年 | 3818篇 |
2015年 | 2988篇 |
2014年 | 3763篇 |
2013年 | 9059篇 |
2012年 | 7035篇 |
2011年 | 8765篇 |
2010年 | 5950篇 |
2009年 | 5848篇 |
2008年 | 8272篇 |
2007年 | 7940篇 |
2006年 | 6951篇 |
2005年 | 6515篇 |
2004年 | 6154篇 |
2003年 | 6282篇 |
2002年 | 5647篇 |
2001年 | 6630篇 |
2000年 | 6620篇 |
1999年 | 5247篇 |
1998年 | 2324篇 |
1997年 | 2227篇 |
1996年 | 2025篇 |
1995年 | 2416篇 |
1994年 | 2126篇 |
1993年 | 2044篇 |
1992年 | 4219篇 |
1991年 | 4438篇 |
1990年 | 4158篇 |
1989年 | 4329篇 |
1988年 | 3901篇 |
1987年 | 3942篇 |
1986年 | 4121篇 |
1985年 | 3885篇 |
1984年 | 3162篇 |
1983年 | 2836篇 |
1982年 | 1981篇 |
1979年 | 2994篇 |
1978年 | 2430篇 |
1977年 | 2034篇 |
1976年 | 2012篇 |
1975年 | 2157篇 |
1974年 | 2609篇 |
1973年 | 2632篇 |
1972年 | 2496篇 |
1971年 | 2310篇 |
1970年 | 2148篇 |
1969年 | 2163篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
G S Johnson M A Turrentine K H Kraus 《Veterinary Clinics of North America: Small Animal Practice》1988,18(1):195-229
The term "von Willebrand's disease," refers to a group of inherited bleeding disorders, all of which are caused by a deficiency of the multimeric plasma glycoprotein, von Willebrand factor. The various forms of canine von Willebrand's disease can be categorized into one of three major types: in type I canine von Willebrand's disease, all sizes of von Willebrand factor multimers can be detected in the plasma; in type II canine von Willebrand's disease, only the smaller von Willebrand factor multimers are found in the plasma (larger multimers are absent); and in type III canine von Willebrand's disease, von Willebrand factor is completely absent from the plasma or present in only trace amounts. Von Willebrand's disease is common in dogs, but some forms of the disease are so mild that they are of questionable clinical significance. 相似文献
992.
993.
Cribb AE Burgener DC Reimann KA 《The Canadian veterinary journal. La revue veterinaire canadienne》1988,29(8):654-657
Seven icteric dogs were determined to have bile duct obstruction secondary to chronic pancreatitis. All dogs had histories of intermittent vomiting and diarrhea. Alkaline phosphatase and alanine aminotransferase activities and total bilirubin concentrations were markedly elevated. Diagnosis was based on exploratory laparotomy and histological examination. Each dog had a 3 to 10 cm mass in the body of the pancreas and obstruction of the common bile duct. Three dogs treated with pancreatectomy, gastrojejunostomy, and cholecystojejunostomy died within five weeks. Three dogs treated with conservative surgical procedures were alive at 8, 16, and 26 months postoperatively. One dog was euthanized because of suspected neoplasia. Hepatic enzyme activity and bilirubin levels decreased markedly in the surviving dogs. Histological examination of the pancreatic masses indicated chronic pancreatitis. Hepatic biopsies revealed evidence of cholestasis. Chronic pancreatitis should be included in the differential diagnoses of icterus, bile duct obstruction, and masses in the pancreas. 相似文献
994.
Kerr RA 《Science (New York, N.Y.)》1988,239(4841):729-730
995.
996.
997.
998.
Dermer OC 《Science (New York, N.Y.)》1988,239(4844):1184-1185
999.
1000.