全文获取类型
收费全文 | 115151篇 |
免费 | 5866篇 |
国内免费 | 77篇 |
专业分类
林业 | 5052篇 |
农学 | 3658篇 |
基础科学 | 588篇 |
12779篇 | |
综合类 | 21715篇 |
农作物 | 4276篇 |
水产渔业 | 5604篇 |
畜牧兽医 | 59130篇 |
园艺 | 1391篇 |
植物保护 | 6901篇 |
出版年
2018年 | 1462篇 |
2017年 | 1567篇 |
2016年 | 1485篇 |
2015年 | 1258篇 |
2014年 | 1539篇 |
2013年 | 4048篇 |
2012年 | 2721篇 |
2011年 | 3426篇 |
2010年 | 2286篇 |
2009年 | 2171篇 |
2008年 | 3364篇 |
2007年 | 3319篇 |
2006年 | 3067篇 |
2005年 | 2925篇 |
2004年 | 2850篇 |
2003年 | 2858篇 |
2002年 | 2651篇 |
2001年 | 3640篇 |
2000年 | 3662篇 |
1999年 | 2954篇 |
1998年 | 1156篇 |
1997年 | 1119篇 |
1995年 | 1316篇 |
1994年 | 1080篇 |
1993年 | 1068篇 |
1992年 | 2380篇 |
1991年 | 2529篇 |
1990年 | 2589篇 |
1989年 | 2492篇 |
1988年 | 2339篇 |
1987年 | 2358篇 |
1986年 | 2367篇 |
1985年 | 2281篇 |
1984年 | 1869篇 |
1983年 | 1672篇 |
1982年 | 1084篇 |
1979年 | 1730篇 |
1978年 | 1372篇 |
1977年 | 1198篇 |
1976年 | 1128篇 |
1975年 | 1270篇 |
1974年 | 1619篇 |
1973年 | 1635篇 |
1972年 | 1678篇 |
1971年 | 1547篇 |
1970年 | 1439篇 |
1969年 | 1379篇 |
1968年 | 1158篇 |
1967年 | 1221篇 |
1966年 | 1097篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
M Washizu K Kobayashi K Misaka T Hayashi G Kinoshita M Kondo S Aoki H Orima T Washizu 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(5):1051-1053
A 2-year-old female Japanese domestic cat weighing 3.6 kg was presented due to marked abdominal distention and was diagnosed as hepatic cyst. The bile acid concentration of the hepatic cyst was as low as the serum bile acid concentration. The membrane of the cysts was excised from the edge of the compressed hepatic tissue and no other surgical manipulation was performed. This surgical procedure is simple and quick compared to hepatic lobectomy, however, it is necessary to evaluate the fluid of the cyst before performing this procedure. 相似文献
102.
Protective activities of heat-inactivated (60 degrees C for 30 min) merthiolate preserved Bordetella bronchiseptica and B. pertussis bacterins were compared in intraperitoneally immunized mice challenged intracerebrally (i.p./i.c.) or intraperitoneally (i.p./i.p.). In the i.p./i.c. assay (Kendrick test), a B. pertussis bacterin protected mice against challenge with B. pertussis 18-323, as well as against phase I cytotoxic and non-cytotoxic strains of B. bronchiseptica. A B. bronchiseptica bacterin, prepared from a phase I cytotoxic strain, gave protection against two phase I B. bronchiseptica strains, irrespective of their cytotoxin-production. A non-cytotoxic phase I strain of B. bronchiseptica elicited protection against the homologous strain only. Neither cytotoxic nor non-cytotoxic B. bronchiseptica strains protected mice challenged with B. pertussis 18-323. Vaccines prepared from phase III strains of B. bronchiseptica were not protective at all against any of the challenge strains. No such differences in the protective activities of the bacterins could be detected by the i.p./i.p. method. They seem to cross-protect equally well. The results indicate that the Kendrick test may be useful in testing potency of different B. bronchiseptica bacterins. 相似文献
103.
A field experiment was conducted during the winter seasons of 1992–93 and 1993–94 at Anand to study the effect of FYM, nitrogen and source of fertilizer on growth and yield of mustard [ Brassica juncea (L.) Czernj & Cosson]. The results showed significant variation in leaf area index (LAI), crop growth rate (CGR), dry matter production and seed yield. The direct effect of farmyard manure (FYM) was conspicuous in improving the growth of mustard. FYM application at 10 tonnes ha−1 significantly increased the LAI, CGR and dry matter accumulation per plant at almost all the stages during first year study (1992–93) and in pooled analysis. Similarly, nitrogen application registered maximum LAI, CGR at 75 kg level and RGR and NAR at 50 kg level at almost all the during both years. Sulphur carrying source (Ammonium sulphate plus single super phosphate) increased all stages growth characters. Maximum dry matter accumulation per plant and seed yield were recorded with highest levels of FYM (20 tonnes ha−1 ), N (75 kg ha−1 ) and source having S. Seed yield was strongly associated with LAI and dry matter accumulation per plant at all the stages. 相似文献
104.
105.
We report on an outbreak of enzootic abortion in a herd of goats with high losses caused by mixed infection with Coxiella burnetii and Chlamydia psittaci. Both agents could be detected by microscopic investigation of smears from afterbirths by Giménez staining and by a capture enzyme-linked immunofluorescence assay (Capture ELIFA). Additionally, Coxiella burnetii was isolated from the same tissues in BGM cell cultures. Serological investigations with CF, indirect ELIFA, and IF tests revealed high antibody titers against both agents in most animals. Coxiella antigen was still detected 91 days later in milk samples of two infected goats by Capture ELIFA. 相似文献
106.
The determination of differentiation and transplantation antigens will be of growing importance in immune diagnosis for individual animals as well as for breeding purposes in populations. Differentiation antigens characterize subsets of cell populations and indicate their functional capacity while transplantation antigens represent markers of individuals of a species. Occurrence and significance of these antigenic systems are briefly reviewed. 相似文献
107.
108.
109.
Serum antibody (virus neutralisation, complement fixation, IgM and IgG) responses to equine herpesvirus-1 (EHV-1) infection were measured in six foals which were initially free from EHV-1 and EHV-4 infection and maternally-derived antibodies. Following primary infection, high titres of virus neutralisation and complement fixation antibodies were detectable against EHV-1, however, corresponding antibody levels against EHV-4 were low or inapparent, although the two viruses share a number of cross-reactive epitopes. In addition, following the primary infection with EHV-1, IgM levels increased before those of IgG, virus neutralisation and complement fixation antibodies, peaked sooner and thereafter declined. Stimulation of IgM levels was observed on secondary infection with EHV-1 given 61 days later. In contrast, IgG, virus neutralisation and complement fixation antibodies following primary infection were more sustained and no increase in their levels was observed on secondary infection. No consistent changes in IgM or IgG levels were seen after administration of dexamethasone to reactivate latent virus. 相似文献
110.
A. T. Szabó 《Genetic Resources and Crop Evolution》2005,52(3):347