全文获取类型
收费全文 | 57625篇 |
免费 | 3062篇 |
国内免费 | 100篇 |
专业分类
林业 | 3532篇 |
农学 | 1726篇 |
基础科学 | 275篇 |
6900篇 | |
综合类 | 10779篇 |
农作物 | 2165篇 |
水产渔业 | 2668篇 |
畜牧兽医 | 28434篇 |
园艺 | 763篇 |
植物保护 | 3545篇 |
出版年
2019年 | 511篇 |
2018年 | 922篇 |
2017年 | 942篇 |
2016年 | 885篇 |
2015年 | 801篇 |
2014年 | 911篇 |
2013年 | 2131篇 |
2012年 | 1834篇 |
2011年 | 1967篇 |
2010年 | 1281篇 |
2009年 | 1300篇 |
2008年 | 1906篇 |
2007年 | 1966篇 |
2006年 | 1809篇 |
2005年 | 1683篇 |
2004年 | 1585篇 |
2003年 | 1545篇 |
2002年 | 1474篇 |
2001年 | 1648篇 |
2000年 | 1607篇 |
1999年 | 1311篇 |
1998年 | 485篇 |
1997年 | 492篇 |
1996年 | 502篇 |
1995年 | 559篇 |
1994年 | 492篇 |
1993年 | 510篇 |
1992年 | 999篇 |
1991年 | 1004篇 |
1990年 | 1006篇 |
1989年 | 1033篇 |
1988年 | 963篇 |
1987年 | 985篇 |
1986年 | 977篇 |
1985年 | 974篇 |
1984年 | 799篇 |
1983年 | 709篇 |
1979年 | 737篇 |
1978年 | 602篇 |
1977年 | 509篇 |
1976年 | 503篇 |
1975年 | 566篇 |
1974年 | 764篇 |
1973年 | 694篇 |
1972年 | 739篇 |
1971年 | 743篇 |
1970年 | 667篇 |
1969年 | 661篇 |
1968年 | 512篇 |
1967年 | 565篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Meat regulations also involve game inspection. This publication deals with the regulations concerning furred game intended for slaughter and furred game hunted for food. 相似文献
42.
Duration of maternal immunity to peste des petits ruminants 总被引:1,自引:0,他引:1
43.
Chicken anemia agent in the United States: isolation of the virus and detection of antibody in broiler breeder flocks 总被引:4,自引:0,他引:4
Chicken anemia agent (CAA) was isolated from broiler chickens in Texas with a blue wing or anemia dermatitis-like syndrome. Specific-pathogen-free chicks inoculated with field material developed anemia, and CAA was isolated in MDCC-MSB1 cells from bone marrow and lymphoid tissue from inoculated chicks. One isolate, designated EF88/78/276, was further characterized. Infectivity of EF88/78/276 was resistant to treatment with chloroform and with heat at 70 C for 5 minutes. EF88/78/276 was indistinguishable from the Cux-1 and Gifu-1 isolates of CAA by cross-neutralization tests. Almost all 1-day-old susceptible chicks inoculated intramuscularly with EF88/78/276 developed anemia, but contact-infected chicks did not. Antibody to CAA was detected in broiler breeder flocks from Texas, the Delmarva peninsula, and Alabama. 相似文献
44.
We studied the ability of lambs to select safe foods in the presence of harmful foods. In a series of feeding experiments, 3- to 6-mo-old lambs were offered a choice between 1) a familiar, safe and a novel, harmful food, 2) a novel, safe and a novel, harmful food and 3) a familiar, harmful and a novel, safe food. All harmful foods were palatable feeds that had been treated with lithium chloride (LiCl), a non-lethal gastrointestinal poison. When lambs ingested a meal composed of a novel food containing LiCl and a familiar, safe food, lambs subsequently avoided the novel food. Lambs avoided the novel food even when the familiar food contained LiCl. The response of lambs varied when lambs were given a choice between a novel, safe food and a novel food containing LiCl. Lambs either avoided the novel food containing LiCl and ingested the safe food or they limited their intake of both novel foods. Their response was dependent on the novelty of the food containing LiCl. When a novel, palatable food contained 2% LiCl, lambs always ate some of the food, even after experiencing illness from ingesting it. Lambs experienced with foods containing LiCl displayed greater food neophobia than lambs naive to LiCl-treated foods. Thus, novelty was the major criterion that lambs used to associate foods with gastrointestinal illness. 相似文献
45.
The anatomical-pathological findings of 15 woolly monkeys were comparable with those described in man with essential benign or malignant hypertension. Kidneys revealed arterio- and arteriolosclerosis or an onion peel-like proliferation, in some cases necrotizing endarteritis. Obesity due to restricted physical activity, unnatural feeding, and psychical and physical stress could have contributed to the development of this condition. Further, high vulnerability of the genus woolly monkey is postulated. Thus, essential hypertension of woolly monkeys appears to be a multifactorial disease. 相似文献
46.
M Steinhardt S Reimer J Kutschke U Bünger 《Archiv fuer experimentelle veterinaermedizin》1989,43(1):111-119
4 female and 2 male untrained fattening pigs, weighing 43.9 +/- 1.6 kg at the beginning of the experiment underwent continuous measurement of VO2, VCO2, and rectal temperature, prior to, during, and after running on a horizontal exercise belt set to speeds of 0.7, 1.3, and 2.5 m.s-1. The highest values of VO2 and VCO2 (ml-min-1/kg-1) and rectal temperature (degrees C) were usually measured few minutes after running. They were 18.84 +/- 3.65 and 20.4 +/- 4.53 as well as 41.2 +/- 0.4, 28.41 +/- 4.07 and 33.26 +/- 5.92 or 41.3 +/- 0.5, 26.21 +/- 7.7 and 32.32 +/- 7.14 as well as 40.5 +/- 0.7, depending on the above belt speeds. Exercise belt speeds of 1.3 to 1.8 m.s-1 were found to be suitable for testing aerobic metabolic capacity of untrained young pigs. 相似文献
47.
48.
49.
50.