全文获取类型
收费全文 | 1054篇 |
免费 | 59篇 |
专业分类
林业 | 45篇 |
农学 | 25篇 |
基础科学 | 8篇 |
178篇 | |
综合类 | 107篇 |
农作物 | 61篇 |
水产渔业 | 49篇 |
畜牧兽医 | 540篇 |
园艺 | 39篇 |
植物保护 | 61篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 19篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2018年 | 15篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 22篇 |
2014年 | 22篇 |
2013年 | 53篇 |
2012年 | 54篇 |
2011年 | 63篇 |
2010年 | 34篇 |
2009年 | 42篇 |
2008年 | 73篇 |
2007年 | 63篇 |
2006年 | 82篇 |
2005年 | 77篇 |
2004年 | 68篇 |
2003年 | 65篇 |
2002年 | 73篇 |
2001年 | 16篇 |
2000年 | 5篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 11篇 |
1996年 | 15篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1969年 | 3篇 |
排序方式: 共有1113条查询结果,搜索用时 78 毫秒
981.
In vitro Utilization of Gold and Green Kiwifruit Oligosaccharides by Human Gut Microbial Populations
Parkar SG Rosendale D Paturi G Herath TD Stoklosinski H Phipps JE Hedderley D Ansell J 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(3):200-207
We examined the effects of whole kiwifruit on gut microbiota using an in vitro batch model of gastric-ileal digestion and colonic fermentation. Faecal fermentations of gold and green kiwifruit, inulin and water (control) digests were performed for up to 48?h. As compared to the control, gold and green kiwifruit increased Bifidobacterium spp. by 0.9 and 0.8 log(10) cfu/ml, respectively (P?0.001), and the Bacteroides-Prevotella-Porphyromonas group by 0.4 and 0.5 log(10) cfu/ml, respectively. Inulin only had a bifidogenic effect (+0.4 log(10) cfu/ml). This was accompanied with increases in microbial glycosidases, especially those with substrate specificities relating to the breakdown of kiwifruit oligosaccharides, and with increased generation of short chain fatty acids. The microbial metabolic activity was sustained for up to 48?h, which we attribute to the complexity of the carbohydrate substrate provided by whole kiwifruit. Kiwifruit fermenta supernatant was also separately shown to affect the in vitro proliferation of Bifidobacterium longum, and its adhesion to Caco-2 intestinal epithelial cells. Collectively, these data suggest that whole kiwifruit may modulate human gut microbial composition and metabolism to produce metabolites conducive to increased bifidobacteria-host association. 相似文献
982.
Sayaka Niwa Katashi Kubo Janet Lewis Rie Kikuchi Manickavelu Alagu Tomohiro Ban 《Breeding Science》2014,64(1):90-96
Fusarium head blight (FHB), caused by Fusarium graminearum, is a serious disease of wheat (Triticum aestivum L.) associated with contamination by the mycotoxin deoxynivalenol (DON). The FHB-resistant wheat cultivar ‘Sumai 3’ has been used extensively around the world. The existence of variation in FHB resistance among ‘Sumai 3’ accessions has been discussed. In this study, genetic variation among ‘Sumai 3’ accessions collected from six countries were identified using SSR markers; our results demonstrate unique chromosome regions in Sumai 3-AUT and Sumai 3-JPN (‘Sumai 3’ accessions from Austria and Japan, respectively). Field evaluation indicated strong resistance to FHB in Sumai 3-AUT. The polymorphic rate (number of polymorphic markers/number of available markers × 100) based on a DArT array was 12.5% between the two ‘Sumai 3’ accessions. Genotyping for DNA markers flanking FHB-resistant quantitative trait loci (QTLs) revealed genetic variations for the QTL regions on 5AS and 2DS; however, no variation was observed for the QTL regions on 3BS and 6B. Thus, the variation in FHB resistance among ‘Sumai 3’ accessions in the field is due to genetic diversity. 相似文献
983.
Stephen N. White Katherine I. O’Rourke Thomas Gidlewski Kurt C. VerCauteren Michelle R. Mousel Gregory E. Phillips Terry R. Spraker 《Canadian journal of veterinary research》2010,74(1):50-53
Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype. 相似文献
984.
Tularemia is a potentially fatal multi-systemic disease of humans and other animals caused by the bacterial pathogen Francisella tularensis. The disease can be transmitted by ticks, biting flies, water exposure, food, and aerosols and occurs around the northern hemisphere including North America, Europe, and Asia. There are several defined species and subspecies, including F. tularensis subsp. tularensis (Jellison Type A) which is pathogenic for rabbits and occurs in North America, F. tularensis subsp. holarctica (Type B) and mediaasiatica which are less pathogenic for rabbits, and F. tularensis subsp. novicida which has been regarded sometimes as the separate species F. novicida. Because it can have a high aerosol-related infection rate, low infectious dose, and ability to induce fatal disease, F. tularensis is considered a potential agent of biological warfare and is classified by the US Department of Health and Human Services as a List A select agent. We discuss microbiological, clinicopathological, epidemiological, and ecological aspects of tularemia. 相似文献
985.
Chopade H Eigenberg D Solon E Strzemienski P Hostetler J McNamara T 《Veterinary therapeutics : research in applied veterinary medicine》2010,11(4):E1-E10
To investigate the cutaneous distribution, localization, and persistence of imidacloprid in dogs, Advantage Topical Solution labeled with carbon 14 (14C) was topically applied as a single treatment at label rates and application pattern based on body weight to two adult beagles. One dog (8.5 kg) received 1.0 mL of the test solution at a single spot in the interscapular area (14 mg active ingredient/kg body weight); the second dog (12.3 kg) was treated with 2.5 mL of the test solution at four sites, each site receiving approximately 0.625 mL, along the dorsal thoracic and lumbar spine area (21 mg active ingredient/kg body weight). Samples of hair, skin surface residue, and skin taken from the application sites and/or distal body regions of the dogs at four intervals between 7 and 56 days after treatment demonstrated the migration of 14C radioactivity from the application sites to distal areas of the canine haircoat and skin. The 14C radioactivity concentrations in the skin biopsy and stratum corneum samples diminished steadily over 56 days after treatment. Microautoradiography of the skin showed focal concentrations of radioactivity in the superficial epidermis, hair follicles, and sebaceous glands. The presence of imidacloprid-derived radioactivity within hair follicles and sebaceous glands and on the skin surface is in good agreement with the reported efficacy of imidacloprid against fleas on dogs and cats for up to 1 month despite posttreatment bathing, shampooing, and/or swimming. 相似文献
986.
Bartholomay LC Waterhouse RM Mayhew GF Campbell CL Michel K Zou Z Ramirez JL Das S Alvarez K Arensburger P Bryant B Chapman SB Dong Y Erickson SM Karunaratne SH Kokoza V Kodira CD Pignatelli P Shin SW Vanlandingham DL Atkinson PW Birren B Christophides GK Clem RJ Hemingway J Higgs S Megy K Ranson H Zdobnov EM Raikhel AS Christensen BM Dimopoulos G Muskavitch MA 《Science (New York, N.Y.)》2010,330(6000):88-90
987.
Andreas Meyer-Aurich Terry W. Griffin Antje Giebel 《Computers and Electronics in Agriculture》2010,74(1):73-79
Knowledge of site-specific response may help farmers to tailor their management decisions with the help of precision farming technologies. However, farmers often have only a vague idea of the economic potential for site-specific management of their fields, which is important for investment decisions on precision farming technologies. This study presents an on-farm experimental approach to identify the economic potential of site-specific fertilization strategies at low costs. A strip trial with winter wheat (Triticum aestivum, L.) was established with precision farming technologies. Twelve different nitrogen fertilizer rates split in two applications were applied to 30 plots over a total strip length of 1.5 km. Geo-referenced yield was recorded with the harvester. Furthermore, electrical conductivity of the soil was measured and grain quality was surveyed with hand selected samples. With the help of advanced spatial statistical methods, within-field site-specific response was modeled with sufficient accuracy at comparably low costs. Electrical conductivity of the soil, elevation above sea level, and derivates of a digital elevation model were used as covariates to identify a possible economic potential for site-specific fertilization. Yield and protein response was best predicted with spatially adjusted regression models with site-characteristics or their interaction with management variables. Protein content was essential for achieving best economic results. The economic potential for site-specific fertilization strategies for the analyzed field was below 2 €/ha. However, the approach to identify the potential may be transferred to other locations with greater potential for site-specific farming. 相似文献
988.
989.
990.
Terry G. McGee 《Asia Pacific viewpoint》2009,50(2):228-246
This paper explores two issues. First, it focuses on the question of what is the most appropriate theoretical framework for the study of the urbanisation process in China and Vietnam over the last 30 years? It is argued that Le Fefebvre's theory of the ‘production of urban space’ offers the most useful approach because the political economy it adopts helps identify the major driving forces in the urbanisation process in these formerly socialist societies. The second issue involves the investigation of the differences and similarities in the urbanisation process in the two countries that are engaged in similar processes of structural economic transformation. The conclusion suggests that despite historical and cultural differences between Vietnam and China, the urbanisation process in both countries is exhibiting converging features as both countries are adopting a form of ‘hybrid urbanisation’ that involves a combination of socialist and market economies that does not involve an inevitable move to ‘capitalism’. 相似文献