全文获取类型
收费全文 | 355篇 |
免费 | 27篇 |
专业分类
林业 | 13篇 |
农学 | 13篇 |
基础科学 | 3篇 |
60篇 | |
综合类 | 38篇 |
农作物 | 4篇 |
水产渔业 | 21篇 |
畜牧兽医 | 205篇 |
园艺 | 1篇 |
植物保护 | 24篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 32篇 |
2012年 | 13篇 |
2011年 | 15篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 8篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 20篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1971年 | 5篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1931年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有382条查询结果,搜索用时 0 毫秒
1.
2.
Petersen MA Hyldig G Strobel BW Henriksen NH Jørgensen NO 《Journal of agricultural and food chemistry》2011,59(23):12561-12568
Globally, aquaculture systems with water recirculation experience increasing problems with microbial taste and odor compounds (TOCs) such as geosmin and 2-methylisoborneol (MIB). This study investigated the content of geosmin and MIB in water and the flesh of 200 rainbow trouts from eight recirculated aquaculture systems in Denmark. TOC content in the fish flesh was measured by a dynamic headspace extraction method and was evaluated by a sensory panel. The results showed significant correlations between TOC content in water and fish and between chemical analysis and sensory perception. When geosmin exceeded 20 ng/L in the water, 96% of the fish had an intense muddy flavor, but below 10 ng geosmin/L, 18% of the fish (only 3% in special depuration ponds) had an intense muddy flavor. The results indicate that TOC levels <10 ng/L will ensure that a negligible portion of the fish obtains an unpalatable taste and flavor due to TOCs. 相似文献
3.
Joko Tri Wibowo Matthias Y. Kellermann Lars-Erik Petersen Yustian R. Alfiansah Colleen Lattyak Peter J. Schupp 《Marine drugs》2022,20(1)
Melanin is a widely distributed and striking dark-colored pigment produced by countless living organisms. Although a wide range of bioactivities have been recognized, there are still major constraints in using melanin for biotechnological applications such as its fragmentary known chemical structure and its insolubility in inorganic and organic solvents. In this study, a bacterial culture of Streptomyces cavourensis SV 21 produced two distinct forms of melanin: (1) a particulate, insoluble form as well as (2) a rarely observed water-soluble form. The here presented novel, acid-free purification protocol of purified particulate melanin (PPM) and purified dissolved melanin (PDM) represents the basis for an in-depth comparison of their physicochemical and biological properties, which were compared to the traditional acid-based precipitation of melanin (AM) and to a synthetic melanin standard (SM). Our data show that the differences in solubility between PDM and PPM in aqueous solutions may be a result of different adjoining cation species, since the soluble PDM polymer is largely composed of Mg2+ ions and the insoluble PPM is dominated by Ca2+ ions. Furthermore, AM shared most properties with SM, which is likely attributed to a similar, acid-based production protocol. The here presented gentler approach of purifying melanin facilitates a new perspective of an intact form of soluble and insoluble melanin that is less chemical altered and thus closer to its original biological form. 相似文献
4.
Petersen AD Walker RD Bowman MM Schott HC Rosser EJ 《Journal of the American Animal Hospital Association》2002,38(5):407-413
Staphylococcus intermedius (S. intermedius) was isolated from 88.6% and 49.4% of skin and ear samples, respectively, during the years 1992 through 1997, and frequency of isolation remained unchanged. More than 95% of all S. intermedius isolates were susceptible to cephalothin and oxacillin, providing support for empirical treatment of canine skin and ear infections with cephalexin. Pseudomonas aeruginosa (P. aeruginosa) was isolated from 7.5% and 27.8% of skin and ear samples, respectively. The frequency of isolation from skin samples increased over the study period. Because of multidrug-resistant profiles for P. aeruginosa isolates, especially for ear isolates, empirical treatment of P. aeruginosa infections is not advisable. 相似文献
5.
OBJECTIVE: To determine pharmacokinetics and metabolic patterns of fenbendazole after IV and oral administration to pigs. ANIMALS: 4 mixed-breed female pigs weighing 32 to 45 kg. PROCEDURE: Fenbendazole was administered IV at a dose of 1 mg/kg. One week later, it was administered orally at a dose of 5 mg/kg. Blood samples were collected for up to 72 hours after administration, and plasma concentrations of fenbendazole, oxfendazole, and fenbendazole sulfone were determined by use of high-pressure liquid chromatography. Plasma pharmacokinetics were determined by use of noncompartmental methods. RESULTS: Body clearance of fenbendazole after IV administration was 1.36 L/h/kg, volume of distribution at steady state was 3.35 L/kg, and mean residence time was 2.63 hours. After oral administration, peak plasma concentration of fenbendazole was 0.07 microg/ml, time to peak plasma concentration was 3.75 hours, and mean residence time was 15.15 hours. Bioavailability of fenbendazole was 27.1%. Oxfendazole was the major plasma metabolite, accounting for two-thirds of the total area under the plasma concentration versus time curve after IV and oral administration. Fenbendazole accounted for 8.4% of the total AUC after IV administration and 4.5% after oral administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that fenbendazole was rapidly eliminated from plasma of pigs. The drug was rapidly absorbed after oral administration, but systemic bioavailability was low. 相似文献
6.
7.
A migration assay was used to separate a pyrantel-susceptible and -resistant isolate of the pig nematode, Oesophagostomum dentatum. The experiment had three steps. In the first step, LD(50) values for pyrantel of the two isolates in the assay were established. In the second step, susceptible and resistant worms were mixed in various proportions prior to exposure to a fixed concentration of pyrantel and thereafter assayed. The inhibition of migration showed to be linearly correlated with the proportion of resistant worms in a sample. In step three, this line was used as a standard curve to predict the number of resistant worms in samples from pigs infected with mixed samples of susceptible and resistant larvae. 相似文献
8.
9.
10.
B. Beier Petersen 《Journal of pest science》1959,32(8):113-117
Ohne Zusammenfassung 相似文献