全文获取类型
收费全文 | 166433篇 |
免费 | 8916篇 |
国内免费 | 124篇 |
专业分类
林业 | 7401篇 |
农学 | 5306篇 |
基础科学 | 974篇 |
20900篇 | |
综合类 | 29078篇 |
农作物 | 6688篇 |
水产渔业 | 8192篇 |
畜牧兽医 | 83790篇 |
园艺 | 2198篇 |
植物保护 | 10946篇 |
出版年
2019年 | 1630篇 |
2018年 | 2409篇 |
2017年 | 2762篇 |
2016年 | 2490篇 |
2015年 | 2113篇 |
2014年 | 2664篇 |
2013年 | 6429篇 |
2012年 | 4962篇 |
2011年 | 6031篇 |
2010年 | 3886篇 |
2009年 | 4025篇 |
2008年 | 5886篇 |
2007年 | 5645篇 |
2006年 | 5263篇 |
2005年 | 4968篇 |
2004年 | 4701篇 |
2003年 | 4820篇 |
2002年 | 4379篇 |
2001年 | 5077篇 |
2000年 | 5110篇 |
1999年 | 4099篇 |
1998年 | 1765篇 |
1997年 | 1700篇 |
1996年 | 1590篇 |
1995年 | 1879篇 |
1994年 | 1697篇 |
1993年 | 1562篇 |
1992年 | 3156篇 |
1991年 | 3314篇 |
1990年 | 3198篇 |
1989年 | 3215篇 |
1988年 | 2950篇 |
1987年 | 2962篇 |
1986年 | 3052篇 |
1985年 | 2931篇 |
1984年 | 2388篇 |
1983年 | 2149篇 |
1982年 | 1465篇 |
1979年 | 2209篇 |
1978年 | 1793篇 |
1977年 | 1508篇 |
1976年 | 1535篇 |
1975年 | 1636篇 |
1974年 | 2007篇 |
1973年 | 1939篇 |
1972年 | 1892篇 |
1971年 | 1821篇 |
1970年 | 1692篇 |
1969年 | 1740篇 |
1967年 | 1527篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
996.
997.
Marie-Etancelin C Basso B Davail S Gontier K Fernandez X Vitezica ZG Bastianelli D Baéza E Bernadet MD Guy G Brun JM Legarra A 《Journal of animal science》2011,89(3):669-679
Genetic parameters of traits related to hepatic lipid metabolism, carcass composition, and product quality of overfed mule ducks were estimated on both parental lines of this hybrid: the common duck line for the maternal side and the Muscovy line for the paternal side. The originality of the statistical model was to include simultaneously the additive genetic effect of the common ducks and that of the Muscovy ducks, revealing a greater genetic determinism in common than in Muscovy. Plasma metabolic indicators (glucose, triglyceride, and cholesterol contents) were heritable, in particular at the end of the overfeeding period, and heritabilities increased with the overfeeding stage. Carcass composition traits were highly heritable in the common line, with values ranging from 0.15 for liver weight, 0.21 for carcass weight, and 0.25 for abdominal fat weight to 0.32 for breast muscle weight. Heritabilities of technological outputs were greater for the fatty liver (0.19 and 0.08, respectively, on common and Muscovy sides for liver melting rate) than for the pectoralis major muscle (between 0.02 and 0.05 on both parental sides for cooking losses). Fortunately, the processing industry is mainly facing problems in liver quality, such as too high of a melting rate, than in meat quality. The meat quality appraisal criteria (such as texture and cooking losses), usually dependent on pH and the rate of decline of pH, were also very lowly heritable. This study demonstrated that genetic determinism of meat quality and ability of overfeeding is not similar in the common population and in the Muscovy population; traits related to fattening, muscle development, and BW have heritability values from 2 to 4 times greater on the common line than on the Muscovy line, which is relevant for considering different selection strategies. 相似文献
998.
A total of 47 stool samples were collected at the same stud farm from young foals with rotavirus diarrhoea and from their stud mares. Illness involved foals during three consecutive winter seasons. Infection in the farm appeared firstly in January-February 2008. After vanishing in the warm seasons, cases reappeared in March 2009 and 2010. Determination of the rotavirus G- and P-types was carried out using nested RT-PCR in samples collected in 2009 and 2010. A total of 19 of 47 samples resulted positive for rotavirus. The G type was determined in 19/47 samples, whereas the P genotype was determined in 17/47 samples. All equine strains presented a G14 VP7 in combination with a P[12] VP4, suggesting persistence of the same viral strain in the stud farm, during at least two consecutive winter periods. Sequence analysis of the genes encoding the outer capsid rotavirus proteins VP7 and VP4 revealed that the virus had a close relationship between strains recently isolated in the rest of Europe. 相似文献
999.
Mendes MC Lima CK Nogueira AH Yoshihara E Chiebao DP Gabriel FH Ueno TE Namindome A Klafke GM 《Veterinary parasitology》2011,180(3-4):383-388
This study was undertaken to determine the flea diversity on urban dogs and cats in Australia in 2009-2010. A total of 2530 fleas were recovered from 291 animals (151 dogs, 69 cats and 71 uncategorised dogs or cats) from veterinary clinics across five states of Australia. The majority of specimens were from coastal areas. The cat flea (Ctenocephalides felis felis) was the most frequent flea species identified (98.8%, 2500/2530). The only other flea species identified was the stickfast flea (Echidnophaga gallinacea) from Western Australia. Sequencing of the cytochrome oxidase subunit II mtDNA revealed a single haplotype across Australia within a subset of C. f. felis (n=19). Our study demonstrated dominance and haplotype homogeneity of C. f. felis on dogs and cats. Although Ctenocephalides canis was recovered from a feral fox, it was not identified from the sample of fleas analysed. This suggests that, under current conditions, it is unlikely that foxes are reservoirs of C. canis for domestic dogs or cats residing in coastal Australia, as previously speculated. 相似文献
1000.