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排序方式: 共有813条查询结果,搜索用时 15 毫秒
41.
Sonnenberg GF Monticelli LA Alenghat T Fung TC Hutnick NA Kunisawa J Shibata N Grunberg S Sinha R Zahm AM Tardif MR Sathaliyawala T Kubota M Farber DL Collman RG Shaked A Fouser LA Weiner DB Tessier PA Friedman JR Kiyono H Bushman FD Chang KM Artis D 《Science (New York, N.Y.)》2012,336(6086):1321-1325
The mammalian intestinal tract is colonized by trillions of beneficial commensal bacteria that are anatomically restricted to specific niches. However, the mechanisms that regulate anatomical containment remain unclear. Here, we show that interleukin-22 (IL-22)-producing innate lymphoid cells (ILCs) are present in intestinal tissues of healthy mammals. Depletion of ILCs resulted in peripheral dissemination of commensal bacteria and systemic inflammation, which was prevented by administration of IL-22. Disseminating bacteria were identified as Alcaligenes species originating from host lymphoid tissues. Alcaligenes was sufficient to promote systemic inflammation after ILC depletion in mice, and Alcaligenes-specific systemic immune responses were associated with Crohn's disease and progressive hepatitis C virus infection in patients. Collectively, these data indicate that ILCs regulate selective containment of lymphoid-resident bacteria to prevent systemic inflammation associated with chronic diseases. 相似文献
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OBJECTIVE: To explore socio-economic factors associated with rising rates of overweight among Vietnamese adults. DESIGN: The study was based on three national surveys of socio-economic factors and health conducted over a 10-year period. The studies were: the Vietnamese Living Standard Survey 1992-1993 (11 982 participants); the Vietnamese Living Standard Survey 1997-1998 (15 975 participants); and the Vietnamese National Health Survey 2001-2002 (94 656 participants). SUBJECTS: Male and female adults >18 years old were stratified by gender, age group, area of residence, occupation, education and relative food expenditures. Overweight was defined using body mass index (BMI) > or = 25 kg m(-2). RESULTS: Overweight rates in Vietnam more than doubled between 1992 and 2002 (from 2.0 to 5.7%). Significant increases were observed for men and women, in urban and rural areas, and for all age groups. In univariate analyses, both age and higher socio-economic status were associated with higher rates of overweight. Using the most recent survey, urban populations were more likely to be overweight than rural ones (odds ratio (OR) = 1.79), white-collar workers were more likely to be overweight than manual labourers (OR = 1.95) and persons in the top level of food expenditures were more likely to be overweight than persons in the bottom level (OR = 4.96) after adjustment for other factors. Education was inversely associated with overweight after adjusting for covariates. CONCLUSION: Economic growth and improved standard of living are associated with higher rates of overweight in nations in early stages of economic development. In Vietnam, higher rates of overweight were observed among the higher income and occupation groups. 相似文献
45.
Hadia OM Khair Ibrahim A Adam Shakir B Bushara Kamal H Eltom Nasreen O Musa Imadeldin E Aradaib 《Irish veterinary journal》2014,67(1):4
Background
Bluetongue virus (BTV) is an insect-transmitted virus, which causes bluetongue disease (BT) in sheep and a fatal hemorrhagic infection in North American white-tailed deer. However, in cattle the disease is typically asymptomatic and no overt clinical signs of disease appear to be associated with BTV infection. Serological evidence and isolation of different BTV serotypes have been reported in Sudan, however, no information is currently available in regard to previous exposure of Sudanese livestock to BTV infection in East Darfur State, Sudan.Aims
To determine the prevalence of BTV antibodies and to identify the potential risk factors associated with BTV infection among cattle in East Darfur State, Sudan.Methods
A total of 224 blood samples were collected randomly from five localities in East Darfur State, Sudan. The serum samples were screened for detection of BTV-specific immunoglobulin G (IgG) antibodies using a competitive enzyme-linked immunosorbent assay (c-ELISA).Results
Serological evidence of BTV infection was observed in 150 out of 224 animals accounting for a 67% prevalence rate among cattle in East Darfur State. Older cattle (>2 years of age) were six times more likely to be infected with BTV (OR = 6.62, CI = 2.87-15.26, p-value = 0.01). Regarding animal source (contact with other herds) as a risk factor, it was shown that cattle purchased from market or introduced from other herds were 3 times at higher risk of being infected with BTV (OR = 3.87, CI = 1.07-13.87, p value = 0.03). Exposure of cattle to the insect vector increased the risk of contracting BTV infection by six times compared to non-exposed cattle (OR = 6.44, CI = 1.53-27.08, p value = 0.01).Conclusion
The present study indicated that age, animal source and the intensity of the insect vector are influential risk factors for BTV infection in cattle in the Darfur region. Surveillance for BTV infection should be extended to include other susceptible ruminants and to study the distribution of the insect vectors to better predict and respond to a possible BTV outbreak in the State of East Darfur, Sudan. 相似文献46.
Abdel-Baset A. Adam Houssni El-Saied Mahmoud K. Soliman 《Wood material science & engineering》2014,9(1):49-57
Sesbania fiber is a fast-growing wood species that has been investigated for medium-density fiberboard (MDF) production. To assess the possibility of applying the local industrial defibration parameters of sugar-cane bagasse (SCB) on defibration of sesbania, the chemical constituents of unfibrated and defibrated sesbania, as well as their thermal stability and scanning electron micrographs, were estimated. Different preparation variables of MDF, such as density, level of urea-formaldehyde (UF) resin (with 0.19% free-formaldehyde [HCHO]), and pressing time were studied, in comparison with that produced by using SCB fibers. The results showed that most of the tested sesbania-based MDFs have mechanical properties that fulfill the minimum requirements of MDF ANSI standard. Additionally, applying 12% UF and pressing for 240 sec provided sesbania-based MDF with optimum reduction in thickness swelling (reached ~7%). It is important to note that the sesbania-based MDF produced under these conditions is characterized by a lower TS property, than that obtained from SCB, or that reported in standards. The preliminary feasibility study revealed that using sesbania fibers will be an added economical potential for MDF production. 相似文献
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Meeting demands for increased cereal production in China 总被引:1,自引:0,他引:1
Meeting demands for increased cereal production in China is a great challenge and this paper provides updated information on cereal production and the potential adaptation of cropping systems to climate change, as well as on progress in improving yield potential and developing molecular markers and GM cereals in China. Maize production and soybean imports are increasing significantly to meet the strong demand for feed by a rapidly growing livestock industry. Extension of the rice and maize growing seasons in northeastern China and improvement of the cropping system through delayed wheat planting have contributed to improving cereal productivity despite changing climatic conditions. Significant improvements in yield potential of rice, maize, and wheat have been achieved. Comparative genomics has been successfully used to develop and validate functional markers for processing quality traits in wheat, and also for developing new varieties. Although transgenic Bt rice and maize, and maize expressing phytase have been developed, their commercialization has not been officially permitted. International collaboration has contributed significantly to cereal production by providing germplasm and improved crop management practices. Full integration of applied molecular technologies into conventional breeding programs and promotion of lower-input technologies, will play a key role in increasing and sustaining future cereal production. 相似文献
49.
Pablo Aran Pablo Aguilar Thomas Bowen Matthew Farson Joseline Tapia Lara Vimercati John L. Darcy Adam J. Solon Dorota Porazinska Steven K. Schmidt Cristina Dorador 《水产资源保护:海洋与淡水生态系统》2021,31(8):2293-2299
- High elevation lakes are extreme ecosystems and serve as sentinels of various global changes.
- An expedition to Volcán Llullaillaco in 1996 discovered an unstudied high-elevation lake (6,170 m a.s.l.) that probably was formed as a result of the past eruptive events or climatic processes such as glacial retreat in the lake basin.
- This article describes an initial physical characterization of the lake and its microbial communities derived from two sampling expeditions in 2013 and 2016.
- The microbial community in the lake, with an area between 1.2 and 1.4 ha and a depth of 6.8 m, was dominated by Proteobacteria, Actinobacteria and Haloarchaea. In addition, 26 bacterial isolates were identified within the genera Subtercola, Xylophilus, Rhodanobacter, Mesorhizobium and Pseudomonas.
- Lago Llullaillaco is one of the highest recorded lakes in the world, and this study highlights the unique microbial diversity of this aquatic ecosystem and the importance of its preservation to understand the complex biological processes under polyextreme conditions.
50.
Small-scale forestry-based enterprises connected with wood processing are becoming of growing importance in the rural economy of developing countries. Little attention has been paid to the characteristics of these enterprises and their role in supporting economic development. The objectives of this study are to: (1) determine the socioeconomic characteristics of the operators of these enterprises; (2) assess the contribution of the informal carpentry sector to operators’ income; and (3) identify the factors limiting the expansion of the sector. The study was carried out in the Singa district, Sinnar State in 2011. Snowball sampling was used to select 250 operators from five markets in the district. The quantitative and qualitative data were collected using Participatory Rural Appraisal methods. The results revealed that most operators involved in the informal carpentry sector are males aged <30 years and their businesses have been in existence for <10 years. Operators’ incomes ranged between USD 100 and 500 monthly on average. The results also indicated that the operators face many constraints (e.g. finance shortage, lack of raw materials, insecure market, lack of technology and lack of organization) to expanding the informal carpentry sector. The study concluded that the informal carpentry sector has potential to contribute to rural economic development through increasing income and reducing rural poverty. 相似文献