全文获取类型
收费全文 | 39134篇 |
免费 | 1042篇 |
国内免费 | 2712篇 |
专业分类
林业 | 6405篇 |
农学 | 4758篇 |
基础科学 | 2054篇 |
6782篇 | |
综合类 | 7269篇 |
农作物 | 3357篇 |
水产渔业 | 2592篇 |
畜牧兽医 | 4333篇 |
园艺 | 1796篇 |
植物保护 | 3542篇 |
出版年
2024年 | 48篇 |
2023年 | 217篇 |
2022年 | 533篇 |
2021年 | 866篇 |
2020年 | 789篇 |
2019年 | 760篇 |
2018年 | 3218篇 |
2017年 | 3378篇 |
2016年 | 1883篇 |
2015年 | 1065篇 |
2014年 | 931篇 |
2013年 | 1177篇 |
2012年 | 2171篇 |
2011年 | 3525篇 |
2010年 | 3489篇 |
2009年 | 2583篇 |
2008年 | 2552篇 |
2007年 | 2948篇 |
2006年 | 1324篇 |
2005年 | 1202篇 |
2004年 | 637篇 |
2003年 | 639篇 |
2002年 | 467篇 |
2001年 | 438篇 |
2000年 | 586篇 |
1999年 | 690篇 |
1998年 | 616篇 |
1997年 | 536篇 |
1996年 | 518篇 |
1995年 | 510篇 |
1994年 | 467篇 |
1993年 | 426篇 |
1992年 | 397篇 |
1991年 | 304篇 |
1990年 | 250篇 |
1989年 | 213篇 |
1988年 | 175篇 |
1987年 | 92篇 |
1986年 | 63篇 |
1985年 | 32篇 |
1984年 | 16篇 |
1983年 | 34篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1977年 | 9篇 |
1974年 | 9篇 |
1964年 | 6篇 |
1963年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
41.
42.
43.
Monde Mapekula Michael Chimonyo Cletos Mapiye Kennedy Dzama 《Tropical animal health and production》2010,42(7):1413-1419
Understanding the utilisation patterns of milk assists in designing appropriate dairy development schemes in rural communities.
The objective of the study was to determine milk utilisation patterns in different smallholder farming systems in the Eastern
Cape Province of South Africa. Data were collected through the administration of recording sheets to 130 randomly selected
households in Alice, Fort Beaufort and Queenstown districts. Amounts of milk produced per household ranged from 9 to 21 l
per household per day. Milk consumption/household/day was similar among the three districts. Milk consumption in the early
lactation doubled the amount consumed in late lactation (P < 0.05). Milk in the communal areas was largely utilised as fresh or sour milk. Fresh milk was mostly used in tea/coffee
or to make porridge for children. Sour milk was consumed with thick boiled maize meal. Fort Beaufort (10.2 ± 1.37 l/day) had
the highest sour milk sales whilst Queenstown had the highest fresh milk sales (9.7 ± 5.57 l/day). It was concluded that quantities
of milk consumed or sold as fresh or sour were generally low and varied across smallholder farming systems. 相似文献
44.
文章从山羊养殖历史、生物学特性、自然社会、经济效益、生态环保、市场消费及国外养殖进展等方面进行研究,认为我国南方农区山羊饲养应回归放牧养羊,可以实现社会生态经济的可持续发展。同时提出放牧养殖的标准化建设思路。 相似文献
45.
U.S Salisu C.A Kudi J.O.O. Bale M Babashani B.Y Kaltungo S.N.A Saidu A Asambe A.Y Baba 《Tropical animal health and production》2017,49(5):1041-1046
A cross-sectional study was carried out to determine the status of Brucella infection in one-humped (Dromedary) camels in the North and Central senatorial districts of Katsina State, Nigeria. Nine hundred and eighty serum samples from live and slaughtered camels were tested. Modified Rose Bengal plate test (RBPT) and serum agglutination test (SAT) with ethylenediaminetetraacetic acid, (EDTA) were used as screening and standard tests, respectively. The prevalence of Brucella antibodies were 110 (11.2%) and 103 (10.5%) for RBPT and SAT, respectively. Of the 472 and 508 serum samples tested from the herds and abattoirs, respectively, 63 (13.3%) and 47 (9.3%) were positive by RBPT while 62 (13.1%) and 41 (8.1%) were positive by SAT, respectively. Based on the results, it was concluded that Brucella antibodies were present in camels in the study area. Poor management practices and mixing of camels with other species of livestock as well as unrestricted movement of camels were proposed to be the reasons for the prevalence of the disease in the study area. In view of the public health importance of the disease, it is recommended that there is the need to develop a strategic plan to decrease spread of brucellosis in the study area. 相似文献
46.
不同的干燥工艺对荷花蜂花粉功能成分的影响 总被引:1,自引:0,他引:1
探讨了5种干燥工艺对荷花蜂花粉功能成分的影响。微波干燥的干燥效率最高,60%火力处理540s可使水分从31.41%降到6.42%;干燥方式对荷花蜂花粉蛋白质影响较小;微波干燥后总黄酮提取率最高,为13.20mg/g;真空冷冻干燥后维生素C和过氧化氢酶含量最高,分别为48.89mg/100g和29.86mg/g·min。总的来说,真空冷冻干燥对荷花蜂花粉的功能成分影响最小;常压恒温干燥对功能成分影响较小、工艺简单、对设备要求低,宜于大规模应用于实际生产中。 相似文献
47.
48.
49.
50.