全文获取类型
收费全文 | 482篇 |
免费 | 46篇 |
专业分类
林业 | 20篇 |
农学 | 15篇 |
基础科学 | 6篇 |
106篇 | |
综合类 | 46篇 |
农作物 | 28篇 |
水产渔业 | 27篇 |
畜牧兽医 | 238篇 |
园艺 | 5篇 |
植物保护 | 37篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 16篇 |
2020年 | 11篇 |
2019年 | 16篇 |
2018年 | 22篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 36篇 |
2010年 | 31篇 |
2009年 | 26篇 |
2008年 | 37篇 |
2007年 | 40篇 |
2006年 | 28篇 |
2005年 | 20篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1965年 | 1篇 |
1957年 | 2篇 |
1955年 | 3篇 |
1935年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有528条查询结果,搜索用时 15 毫秒
131.
132.
Due to environmental concern a lot of effort has been dedicated to improve the utilisation of phytate phosphorus (P) in cereals and seeds. Consequently, microbial phytases are added to pig diets at the expense of feed phosphates. However, there is still a need for inclusion of feed phosphate, especially in diets for young piglets and lactating sows in order to meet their P requirement. This creates a demand for feed phosphates with a high P availability. Fourteen feed phosphates, including two newly developed monocalcium phosphates (MCP), were tested in this experiment. For each source, a series of 5 diets was prepared by inclusion of increasing amounts of either MCP or MSP. These diets were offered to pigs kept in metabolism crates (6 pigs on each of the 5 diets). After 5 days adaptation, total collection of faeces and urine was performed for 7 days. P availability in each source was determined by regression of the net absorption of P on P-intake. The experiment revealed that MSP had the highest availability (79%) and the availability of all the tested phosphates varied between 50 and 79%. The new MCPs proved to be 71 and 75% available. 相似文献
133.
Louise L. Southwood BVSc MS PhD DACVS DACVECC Gail Russell BS 《Journal of Veterinary Emergency and Critical Care》2007,17(4):382-390
Objective: To compare clinical findings in horses/foals with peritonitis that: (1) had no concurrent (NCA) versus a concurrent abnormality found during hospitalization, (2) survived to discharge versus did not survive to discharge, and (3) survived to discharge without surgery versus did not survive to discharge without surgery. Design: Retrospective study. Setting: George D. Widener Hospital for Large Animals at New Bolton Center. Animals: Horses/foals admitted between 1992 and 2002 with a diagnosis of peritonitis. A diagnosis of peritonitis within 4 days of presentation and peritoneal fluid nucleated cell count >10,000/μL were required for study inclusion. Horses/foals were excluded if the peritonitis was secondary to gastrointestinal or reproductive tract perforation, a complication of exploratory celiotomy, or if peritonitis was not diagnosed until surgery or necropsy. Interventions: None. Measurements and main results: Information obtained from the medical records included clinical findings at presentation and during the initial 4 days of hospitalization. Outcome was defined as: (1) NCA (yes/no), (2) survived to discharge (yes/no), and (3) survived to discharge without surgery (yes/no). Forty‐two percent (23/55) of horses/foals had NCA; 78% (43/55) survived to discharge, and 68% (36/55) survived to discharge without surgery. Horses/foals with peritonitis that had any one of the following clinical findings were likely to survive to discharge without surgery: no signs of abdominal pain, normal/improved rectal temperature, normal/improved intestinal borborygmi, normal fecal production, no abnormal findings on abdominal palpation per rectum, no nasogastric reflux, or yellow/orange peritoneal fluid. Conclusion: Clinical findings can be used to identify equine peritonitis cases that will respond favorably to medical therapy. 相似文献
134.
K. Blaabjerg D. Carlson J. Hansen-Mller A.-H. Tauson H.D. Poulsen 《Livestock Science》2007,109(1-3):240
A series of in vitro experiments simulating liquid feeding were performed to evaluate the effect of microbial phytase addition, heat-treatment and soaking time on degradation of phytate and lower inositol phosphates when soaking compound wheat/soybean meal diets or the single feedstuffs wheat or soybean meal. The effect of phytase addition on phytate degradation was greatest in soybean meal, almost intermediate for wheat/soybean meal diets and not detectable in wheat, which might be due to a better accessibility to phytate in soybean meal compared with wheat. Heat-treatment seemed to enhance the accessibility between phytase and phytate, whereby phytate degradation was stimulated. Additionally, it was shown that wheat phytase is able to stimulate degradation of phytate in soybean meal. Independent of treatment, the amount of IP5–IP2 was extremely small in relation to phytate in both wheat and soybean meal, indicating that when one phosphate group is removed from the phytate complex, degradation of IP5–IP2 is completed. Consequently, it is anticipated that liquid feeding might result in a higher digestibility of plant P compared with dry feeding of pigs. 相似文献
135.
The acid-base balance in small carnivores (mink, Mustela vison) was examined during 6 feeding periods, when the same animals were given different feeds during a prolonged time. The feeds consisted of normal farm feed to which different amounts of sulphuric acid-preserved feed and feed silaged with organic acids were added (Tables I--II). When the pH of the feed was decreased to below 5.5, the acid-base balance of the animals was changed and metabolic acidosis occurred (Tables III--V, Fig. 1). On neutralization of the acid-preserved feed a normal acid-base balance could be maintained. However, the growth of the animals was reduced after prolonged feeding with silage as they lost weight during the following periods (Table vii). 相似文献
136.
137.
Poulsen J Permin A Hindsbo O Yelifari L Nansen P Bloch P 《Preventive veterinary medicine》2000,45(3-4):237-245
We conducted a cross-sectional study to determine the prevalence and species of gastro-intestinal helminths and haemoparasites in 100 chickens kept under extensive management systems in Ghana, West Africa. All the examined chickens (100%) were infected with gastro-intestinal helminths; a total of 18 species were detected. The species and their prevalences were: Acuaria hamulosa (25%), Allodapa suctoria (20%), Ascaridia galli (24%), Capillaria spp. (60%), Choanotaenia infundibulum (13%), Gongylonema ingluvicola (62%), Heterakis gallinarum (31%), H. isolonche (16%), Hymenolepis spp. (66%), Raillietina cesticillus (12%), R. echinobothrida (81%), R. tetragona (59%), Strongyloides avium (2%), Subulura strongylina (10%), Tetrameres fissispina (58%), Trichostronygylus tenuis (2%), and finally one unidentified acanthocephalan (1%) and one unidentified trematode (1%). Thirty-five per cent of the chickens were infected with the haemoparasites Aegyptinella pullorum and Plasmodium juxtanucleare (prevalences 9% and 27%, respectively). Association between chicken sex and prevalences was not significant. An over-dispersed distribution was seen for most of the helminth species. 相似文献
138.
Leigh Cuttell Maria Angeles Gómez-Morales Beth Cookson Peter J. Adams Simon A. Reid Paul B. Vanderlinde Louise A. Jackson C. Gray Rebecca J. Traub 《Veterinary parasitology》2014,199(3-4):179-190
Trichinella surveillance in wildlife relies on muscle digestion of large samples which are logistically difficult to store and transport in remote and tropical regions as well as labour-intensive to process. Serological methods such as enzyme-linked immunosorbent assays (ELISAs) offer rapid, cost-effective alternatives for surveillance but should be paired with additional tests because of the high false-positive rates encountered in wildlife. We investigated the utility of ELISAs coupled with Western blot (WB) in providing evidence of Trichinella exposure or infection in wild boar. Serum samples were collected from 673 wild boar from a high- and low-risk region for Trichinella introduction within mainland Australia, which is considered Trichinella-free. Sera were examined using both an ‘in-house’ and a commercially available indirect-ELISA that used excretory–secretory (E/S) antigens. Cut-off values for positive results were determined using sera from the low-risk population. All wild boar from the high-risk region (352) and 139/321 (43.3%) of the wild boar from the low-risk region were tested by artificial digestion. Testing by Western blot using E/S antigens, and a Trichinella-specific real-time PCR was also carried out on all ELISA-positive samples. The two ELISAs correctly classified all positive controls as well as one naturally infected wild boar from Gabba Island in the Torres Strait. In both the high- and low-risk populations, the ELISA results showed substantial agreement (k-value = 0.66) that increased to very good (k-value = 0.82) when WB-positive only samples were compared. The results of testing sera collected from the Australian mainland showed the Trichinella seroprevalence was 3.5% (95% C.I. 0.0–8.0) and 2.3% (95% C.I. 0.0–5.6) using the in-house and commercial ELISA coupled with WB respectively. These estimates were significantly higher (P < 0.05) than the artificial digestion estimate of 0.0% (95% C.I. 0.0–1.1). Real-time PCR testing of muscle from seropositive animals did not detect Trichinella DNA in any mainland animals, but did reveal the presence of a second larvae-positive wild boar on Gabba Island, supporting its utility as an alternative, highly sensitive method in muscle examination. The serology results suggest Australian wildlife may have been exposed to Trichinella parasites. However, because of the possibility of non-specific reactions with other parasitic infections, more work using well-defined cohorts of positive and negative samples is required. Even if the specificity of the ELISAs is proven to be low, their ability to correctly classify the small number of true positive sera in this study indicates utility in screening wild boar populations for reactive sera which can be followed up with additional testing. 相似文献
139.
140.
Saint André Av Blackwell NM Hall LR Hoerauf A Brattig NW Volkmann L Taylor MJ Ford L Hise AG Lass JH Diaconu E Pearlman E 《Science (New York, N.Y.)》2002,295(5561):1892-1895
Parasitic filarial nematodes infect more than 200 million individuals worldwide, causing debilitating inflammatory diseases such as river blindness and lymphatic filariasis. Using a murine model for river blindness in which soluble extracts of filarial nematodes were injected into the corneal stroma, we demonstrated that the predominant inflammatory response in the cornea was due to species of endosymbiotic Wolbachia bacteria. In addition, the inflammatory response induced by these bacteria was dependent on expression of functional Toll-like receptor 4 (TLR4) on host cells. 相似文献