全文获取类型
收费全文 | 854篇 |
免费 | 58篇 |
专业分类
林业 | 11篇 |
农学 | 23篇 |
基础科学 | 1篇 |
70篇 | |
综合类 | 141篇 |
农作物 | 19篇 |
水产渔业 | 32篇 |
畜牧兽医 | 555篇 |
园艺 | 19篇 |
植物保护 | 41篇 |
出版年
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 21篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 54篇 |
2012年 | 29篇 |
2011年 | 47篇 |
2010年 | 30篇 |
2009年 | 17篇 |
2008年 | 30篇 |
2007年 | 28篇 |
2006年 | 29篇 |
2005年 | 21篇 |
2004年 | 31篇 |
2003年 | 26篇 |
2002年 | 26篇 |
2001年 | 26篇 |
2000年 | 31篇 |
1999年 | 28篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 31篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 21篇 |
1985年 | 22篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1980年 | 9篇 |
1979年 | 14篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 4篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1967年 | 4篇 |
排序方式: 共有912条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
G J Collins J D Rosen 《Journal of the Association of Official Analytical Chemists》1979,62(6):1274-1280
A method for the analysis of T-2 toxin in milk is presented. Ethyl acetate extracts of milk samples which had been spiked with T-2 toxin were purified by thin layer chromatography and derivatized with N,O-bis(trimethylsilyl)acetamide to produce the T-2 toxin trimethylsilyl ether (T-2 toxin-TMS). N,O-bis(trimethylsilyl-d9)acetamide was used to make T-2 toxin d9-trimethylsilyl ether (T-2 toxin-d9 TMS) which was added to the derivatized milk extract as an internal standard. Samples were analyzed by combined gas-liquid chromatography/mass spectrometry using either electron impact ionization or chemical ionization mass spectrometry. In electron impact ionization analyses, simultaneous monitoring of the T-2 toxin-TMS fragment ion at m/z 436 and the T-2 toxin-d9TMS fragment ion at m/z 445 gave a T-2 toxin-TMS detectability estimated at 6 microgram/kg. In chemical ionization analyses, the T-2 toxin-TMS fragment ion at m/z 377 and the T-2 toxin-d9TMS fragment ion at m/z 386 were simultaneously monitored to give a T-2 toxin-TMS detectability estimated at 3 microgram/kg. Average recovery was 85% at 200 microgram/kg and 65% at 20 microgram/kg. 相似文献
5.
6.
The effects of exposure period and phosphine concentration on mortality of susceptible and resistant Sitophilus oryzae (L) were investigated. Although S oryzae is one of the world's most serious pests of stored grain there are few data on the practical significance of phosphine resistance in this species. The strains investigated were an Australian susceptible strain, a homozygous resistant strain exhibiting a level of resistance common in Australia and an unselected field strain from China with a much stronger resistance. Fumigations were carried out at 25 degrees C on adults and mixed-age cultures. For adults of all three strains and mixed-age cultures of the susceptible and resistant Australian strains, the relationship between concentration and time could be described by equations of the form Cnt = k. In all cases n < 1, indicating that time was a more important variable than concentration. In all fumigations of adults the resistant strains were harder to kill than the susceptible strain. However, in fumigations of mixed-age cultures, which contained the tolerant pupal stage, the difference between susceptible and resistant strains was more pronounced at lower concentrations than higher concentrations. For example, at 0.02 mg litre-1 the estimated LT99.9 for mixed-age cultures of the Australian resistant strain (27 days) is 3.4 times that of the susceptible strain (8 days), but at 1 mg litre-1 there is no difference between the two strains (4 days). Limited data on the Chinese resistant strain supported this finding. Twenty-three days exposure at 0.02 mg litre-1 had no effect on mixed-age cultures of this strain, but there were no survivors after 5 days exposure to 1 mg litre-1. 相似文献
7.
Buergelt CD Layton AW Ginn PE Taylor M King JM Habecker PL Mauldin E Whitlock R Rossiter C Collins MT 《Veterinary pathology》2000,37(5):428-438
Gross and histopathologic examinations were performed on 70 North American bison (Bison bison) from a Mycobacterium avium paratuberculosis culture-positive herd. The bison examined were part of a breeding herd totaling 2,800 animals. Eight of 70 (11%) animals had gross findings of intestinal mucosal thickening, and 16 of 70 (23%) of the animals had enlarged mesenteric lymph nodes. Histologic lesions compatible with Johne's disease were diagnosed in 30 of 70 (43%) bison on the basis of the demonstration of noncaseating granulomatous inflammatory infiltrates and of one or more acid-fast bacilli characteristic of Mycobacterium avium paratuberculosis. A suspicious diagnosis of Johne's disease was obtained in 11 of 70 (16%) bison on the basis of the observation of noncaseating granulomatous inflammatory infiltrates without demonstrable acid-fast bacteria. Twenty-nine of 70 (41%) animals were assessed as histologically paratuberculosis free. Histologic results were compared to Johne's disease tests such as culture, serology, and polymerase chain reaction, which were performed on some of the cohort animals. 相似文献
8.
9.
Rapid detection of canine parvovirus in feces using monoclonal antibodies and enzyme-linked immunosorbent assay 总被引:2,自引:0,他引:2
M M Mildbrand Y A Teramoto J K Collins A Mathys S Winston 《American journal of veterinary research》1984,45(11):2281-2284
Monoclonal antibodies were used to develop a double antibody enzyme-linked immunosorbent assay for the detection of canine parvovirus (CPV) antigen in fecal samples. The assay was specific for the hemagglutinating protein of CPV and detected as little as 1.5 ng of virus within a 15-minute incubation period. The use of monoclonal antibodies against 2 epitopes on the CPV antigen permitted the simultaneous addition of test sample and enzyme-conjugated antibody, thus considerably simplifying the manipulations required for the assay. Results were visually determined without special instrumentation. Clinical studies revealed greater than 95% correlation between enzyme-linked immunosorbent assay results and hemagglutination titers. 相似文献
10.
A neutralizing antibody selected from plasma cells that binds to group 1 and group 2 influenza A hemagglutinins 总被引:2,自引:0,他引:2
Corti D Voss J Gamblin SJ Codoni G Macagno A Jarrossay D Vachieri SG Pinna D Minola A Vanzetta F Silacci C Fernandez-Rodriguez BM Agatic G Bianchi S Giacchetto-Sasselli I Calder L Sallusto F Collins P Haire LF Temperton N Langedijk JP Skehel JJ Lanzavecchia A 《Science (New York, N.Y.)》2011,333(6044):850-856
The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency. 相似文献