全文获取类型
收费全文 | 211430篇 |
免费 | 11377篇 |
国内免费 | 122篇 |
专业分类
林业 | 8541篇 |
农学 | 6420篇 |
基础科学 | 1483篇 |
24351篇 | |
综合类 | 39789篇 |
农作物 | 8096篇 |
水产渔业 | 10139篇 |
畜牧兽医 | 107347篇 |
园艺 | 2603篇 |
植物保护 | 14160篇 |
出版年
2018年 | 2506篇 |
2017年 | 2770篇 |
2016年 | 2637篇 |
2015年 | 2315篇 |
2014年 | 2759篇 |
2013年 | 7950篇 |
2012年 | 5364篇 |
2011年 | 6651篇 |
2010年 | 4294篇 |
2009年 | 4306篇 |
2008年 | 6611篇 |
2007年 | 6182篇 |
2006年 | 5952篇 |
2005年 | 5619篇 |
2004年 | 5568篇 |
2003年 | 5549篇 |
2002年 | 5449篇 |
2001年 | 6535篇 |
2000年 | 6370篇 |
1999年 | 4981篇 |
1998年 | 2114篇 |
1997年 | 2153篇 |
1995年 | 2503篇 |
1994年 | 2331篇 |
1993年 | 2219篇 |
1992年 | 4514篇 |
1991年 | 4807篇 |
1990年 | 4792篇 |
1989年 | 4788篇 |
1988年 | 4385篇 |
1987年 | 4517篇 |
1986年 | 4658篇 |
1985年 | 4464篇 |
1984年 | 3750篇 |
1983年 | 3363篇 |
1982年 | 2312篇 |
1981年 | 2176篇 |
1980年 | 2063篇 |
1979年 | 3371篇 |
1978年 | 2850篇 |
1977年 | 2367篇 |
1976年 | 2213篇 |
1975年 | 2325篇 |
1974年 | 3051篇 |
1973年 | 3130篇 |
1972年 | 3052篇 |
1971年 | 2801篇 |
1970年 | 2635篇 |
1969年 | 2428篇 |
1967年 | 2064篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
911.
Fatty acid profiles and sensory and carcass traits of tissues from steers and swine fed an elevated monounsaturated fat diet 总被引:4,自引:0,他引:4
L C St John C R Young D A Knabe L D Thompson G T Schelling S M Grundy S B Smith 《Journal of animal science》1987,64(5):1441-1447
Twelve Angus X Hereford steers were assigned to either a control high-energy diet or a test diet consisting of 20% rapeseed at the expense of 20% corn. Twelve pigs were allotted to a control diet and two test diets containing either 10 or 20% canola oil (CO). Both CO and oil in the rapeseed contained 60 to 64% oleic acid. Cattle fed rapeseed exhibited little effect from the diet due to apparent indigestibility of the rapeseed. Total saturated fatty acids decreased from 40% in adipose tissue of the control pigs to 15% in the 20% CO-fed pigs. The ratio of monounsaturated to saturated fatty acids (M/S) increased from 1.19 in adipose tissue from control pigs to 3.63 with the addition of 20% CO to the diet. In muscle, the M/S ratio increased from 1.21 in control pigs to 2.46 in the 20% CO treatment group. The percentage of the saturated fatty acids in muscle decreased from 42% in the control to 23% in the 20% CO treatment. Significant increases in "oiliness" and decreases in fat firmness were observed when increasing levels of canola oil were fed. Sensory traits, cooking loss and shear-force values of pork chops were similar among treatment groups. In conclusion, monounsaturated fatty acid content can be elevated substantially in pork without adversely influencing the quality of the meat, thus producing a product perceived to be more healthful by the consumer. 相似文献
912.
S R van Amstel F Reyers P T Oberem O Matthee 《The Onderstepoort journal of veterinary research》1987,54(1):45-48
Experimentally-induced cases of sweating sickness in calves were used in an effort to correlate the blood chemistry with some of the known pathological changes. Results showed that the "sweating" associated with necrotic dermatitis did not alter blood electrolyte levels. Laboratory evidence of a disseminated intravascular coagulopathy was found which correlated with the microthrombi described in cases of sweating sickness. A high blood cortisol level was found in one of the animals that died from the disease and could possibly be used as a prognostic indicator in clinical cases. Recommendations are made with regard to the supportive treatment based on the clinical pathological findings. 相似文献
913.
914.
915.
916.
917.
918.
919.
920.