全文获取类型
收费全文 | 628篇 |
免费 | 34篇 |
国内免费 | 2篇 |
专业分类
林业 | 30篇 |
农学 | 17篇 |
基础科学 | 3篇 |
99篇 | |
综合类 | 54篇 |
农作物 | 23篇 |
水产渔业 | 53篇 |
畜牧兽医 | 337篇 |
园艺 | 25篇 |
植物保护 | 23篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 21篇 |
2020年 | 29篇 |
2019年 | 28篇 |
2018年 | 25篇 |
2017年 | 23篇 |
2016年 | 17篇 |
2015年 | 19篇 |
2014年 | 30篇 |
2013年 | 29篇 |
2012年 | 38篇 |
2011年 | 55篇 |
2010年 | 30篇 |
2009年 | 38篇 |
2008年 | 17篇 |
2007年 | 24篇 |
2006年 | 25篇 |
2005年 | 15篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 15篇 |
1999年 | 15篇 |
1997年 | 2篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1981年 | 6篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1955年 | 2篇 |
1954年 | 2篇 |
1953年 | 2篇 |
1947年 | 2篇 |
1907年 | 1篇 |
1906年 | 1篇 |
1905年 | 1篇 |
排序方式: 共有664条查询结果,搜索用时 289 毫秒
1.
猪对维生素的需要量主要取决于性能测定时某种能导致最大生长的维生素在日粮中的浓度。然而,某些维生素还可引起一些代谢效应,从而除了可改变生长率之外还可能改变生长的组分。 相似文献
2.
Charles R. Weirich Clifford C. O'Neal Brendan C. Delbos C. Greg Lutz 《Journal of the World Aquaculture Society》2001,32(1):112-116
Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry. 相似文献
3.
K Ueland H Lutz 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1992,39(1):53-58
Serum samples from 224 Norwegian cats were analyzed for the presence of feline leukemia virus (FeLV) p27 common core antigen, and for antibodies to feline immunodeficiency virus (FIV). Ninety specimens originated from the serum bank at the central referral clinic at the Norwegian College of Veterinary Medicine, which had been collected during the years 1983-1989; 67 sera were submitted from veterinarian practitioners; while 67 sera originated from cats presented for euthanasia. The cats were classified into one "healthy" and one "sick" group. Only 2.2% of sick cats and 1.2% of healthy cats showed FeLV antigenemia, a finding which is lower than which has been reported from many other countries. The prevalence of FIV antibodies was 10.1% in sick cats and 5.9% in healthy cats. Antibodies to FIV was most prevalent in male cats (14.7%) than in female cats (2.1%), and more prevalent among domestic cats (12.0%) compared to pedigree cats (2.4%). Antibodies to FIV in the cats demonstrated increasing prevalence with increasing age. It may be concluded that FeLV causes minor problems in Norwegian cats, while FIV is present in a similar prevalence to what is reported from other countries. 相似文献
4.
5.
Paixão Sonália Ferreira Fritzen Juliana Torres Tomazi Crespo Sarah Elizabeth Izzo de Moraes Pereira Helder Alfieri Alice Fernandes Alfieri Amauri Alcindo 《Tropical animal health and production》2018,50(8):1947-1950
Tropical Animal Health and Production - Serological studies have characterized the presence of the bovine viral diarrhea virus (BVDV) infection in water buffalo herds worldwide. However, the... 相似文献
6.
Ana Carina Heil da Silva Matos Angélica Consalter Bárbara Paula dos Santos Batista Ana Beatriz Monteiro Fonseca Ana Maria Reis Ferreira Juliana da Silva Leite 《Reproduction in domestic animals》2021,56(4):667-672
Granulosa cell tumour, an ovarian neoplasm of stromal origin, is an important tumour related to oestrogenic dominance syndrome and cystic endometrial hyperplasia–pyometra complex. In order to analyse ovarian tumour´s malignant potential, immunohistochemical markers can be used, such as anti-HER2 and anti-Ki-67. The aim of this study was to evaluate the expression of immunohistochemical markers HER-2 and Ki-67 in granulosa cell tumour from bitches´ ovaries. In HER-2 immunomarker analysis using the HercepTest® method, most tumours were classified as 2+ (moderate labelling). Concerning Ki-67 immunomarker, only one case was described as having a high proliferative index. An association was found between immunostained cell percentage by anti-HER-2 antibodies and high pleomorphism, represented by the pattern of follicular/trabecular tumour arrangement. There was no correlation between anti-Ki-67 and anti-HER-2 antibody immunostaining intensities, probably due to only one case with a high Ki-67 index. With an effective protocol for HER-2 and Ki-67 immunohistochemical identification in granulosa cell tumours in bitches, it was possible to characterize this neoplasm proliferation profile. 相似文献
7.
8.
Effect of the Glucagon‐like Peptide‐1 Analogue Exenatide Extended Release in Cats with Newly Diagnosed Diabetes Mellitus 下载免费PDF全文
9.
Determination of hematologic and blood chemical reference values in fattening pigs of different ages
In swine medicine, the determination of hematology and blood chemistry parameters is of primary interest in connection with the detection of herd problems. For the evaluation of laboratory results the availability of reference values is a prerequisite. So far, no reference values of fattening pigs have been available in Switzerland. For this reason, in the present study reference values for hematology and blood chemistry were determined for two bodyweight categories, 40-60 kg (group 1) and 85-110 kg (group 2). Hematocrit, hemoglobin and RBC counts were lower in animals in group 1. The number of segmented neutrophils was markedly higher in group 1. Lymphocyte counts exceeded neutrophil values in both groups. Concentrations of total bilirubin, AST, CK and LDH partly reached very high levels due to hemolysis or contamination of the blood samples with muscle tissue. 相似文献
10.
H. Lutz S. Bruggmann L. Corboz R. Müller W. Limacher H. Weber K. Wissler G.H. Theilen 《Veterinary immunology and immunopathology》1981,2(5):425-440
Complex antigenic mixtures were separated on polyacrylamide gels in the presence of SDS. After electrophoresis, the gels were cut into equal fractions. Antigens were eluted from the fractions and could be bound to different solid phases on which a conventional enzyme-linked immunosorbent assay was performed. Antibody binding fractions could then be related with the bands of a stained gel run in parallel. This technique proved to be fast and sensitive. Antigens present in nanogram amounts in individual fractions were sufficient for the detection of specific antibody. We describe here the application of this technique to antibodies specific of parasite, viral, bacterial and mycoplasmal antigens and to antibodies against hormones and a muscle protein. 相似文献