全文获取类型
收费全文 | 255篇 |
免费 | 14篇 |
专业分类
林业 | 10篇 |
农学 | 4篇 |
基础科学 | 2篇 |
39篇 | |
综合类 | 63篇 |
农作物 | 24篇 |
水产渔业 | 10篇 |
畜牧兽医 | 100篇 |
园艺 | 5篇 |
植物保护 | 12篇 |
出版年
2023年 | 3篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2013年 | 6篇 |
2012年 | 19篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1995年 | 4篇 |
1992年 | 3篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1981年 | 3篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1948年 | 2篇 |
1947年 | 4篇 |
1946年 | 3篇 |
1945年 | 2篇 |
1944年 | 3篇 |
1943年 | 5篇 |
1935年 | 2篇 |
1933年 | 2篇 |
1911年 | 2篇 |
排序方式: 共有269条查询结果,搜索用时 31 毫秒
51.
52.
53.
54.
55.
Burke SJ McCarthy SN O'Neill JL Hannon EM Kiely M Flynn A Gibney MJ 《Public health nutrition》2007,10(6):599-607
OBJECTIVES: To examine the influence of eating location on the quality of the diets of Irish children and to compare intakes at home with intakes at other people's homes and intakes outside the home, and to compare intakes at various locations outside the home. DESIGN: Food intake was measured using a 7-day weighed diary in 594 children from the Republic of Ireland (aged 5-12 years). Details of where the food was prepared or obtained were also recorded. RESULTS: Eighty-nine per cent of all eating occasions occurred at home; < 6% occurred at both other people's homes and outside the home (takeaway, restaurant, shop, other). The percentage of food energy from fat was above the recommended 35% at other people's homes and outside the home, specifically at takeaways and restaurants. Fibre and micronutrient intakes (per 10 MJ) were significantly higher at home than at the other locations (P < 0.05). Within the 'out' locations, fibre and micronutrient intakes were generally higher at restaurants and lower at shops. High consumers of foods outside the home had a statistically significant, but relatively small decline in nutrient intakes compared with non- or low consumers. Chips and processed potatoes, meat products, savouries, sugars and confectionery, and savoury snacks made the greatest contribution to foods consumed outside the home. CONCLUSIONS: The main focus of nutrition policies to improve the diets of Irish children should be the home environment rather than the food service sector. However, guidelines could call for better food choices outside the home to improve nutrient intakes. 相似文献
56.
High levels of anthelmintic resistance in gastrointestinal nematodes (GIN) of small ruminants have created the need for alternative approaches to parasite control. Copper oxide wire particles (COWP; 2g) have proven effective in decreasing GIN infection in lambs. However, the risk of copper toxicity has limited the usefulness of this approach. Recently, smaller doses (0.5 and 1g) have proven effective in GIN control, reducing the risk of toxicity. The objective of this study was to examine the effectiveness and risk of toxicity using multiple small doses of COWP for GIN control in lambs between weaning and market weight. Dorper crossbred ram lambs were orally administered levamisole (Levasol, 8.0mg/kg; n=8), 0.5g (n=9), or 1g COWP (n=9) at weaning (Day 0; 118+/-2 days of age; late May 2005) and again at 6-week intervals for a total of four treatments. A pooled fecal culture determined that Haemonchus contortus was the predominant gastrointestinal parasite at weaning. Lambs grazed bermudagrass pastures and were supplemented with up to 500g corn/soybean meal and free choice trace mineralized salt. Fecal egg counts (FEC), packed cell volume (PCV), and plasma aspartate aminotransferase (AST) activity were determined every 14 days and lambs weighed every 28 days. GIN infection reached a peak at Day 42 (high FEC, low PCV). COWP effectively reduced FEC on Days 0 and 42 compared with the previous week, but did not reduce FEC on Days 84 and 126 (treatment by time interaction, P<0.005). Plasma AST activity and weight gains were similar among treatment groups throughout the study period. Concentrations of copper in the liver on Day 155 were greater in COWP-treated lambs (P<0.001), but all concentrations were normal. Multiple doses of COWP were as effective as levamisole for control of H. contortus without risk of copper toxicity. 相似文献
57.
The objective of this study was to determine the effectiveness of a sustained-release multi-trace element/vitamin ruminal bolus (TEB) containing copper administered to mature does for control of gastrointestinal nematodes (GIN) during summer months and during late gestation. Haemonchus contortus was the predominant nematode during these trials. In Experiment 1, yearling Spanish does were untreated or administered TEB (n=11/group) on Day 0 (August 2005) prior to breeding. In Experiment 2, Spanish and Boer does were untreated or administered TEB 6 weeks before kidding. Fecal egg counts (FEC) and blood packed cell volume (PCV) were determined weekly between Days 0 and 42. In both experiments, FEC were reduced within 7 days in TEB-treated compared with untreated does. PCV was similar between treatment groups (Experiment 1) or tended to be lower in the TEB group (Experiment 2). GIN control did not persist more than 28 days. These studies suggest that TEB may be an effective means of GIN control in mature goats, but additional control measures may be necessary. 相似文献
58.
Burke B 《Science (New York, N.Y.)》2006,314(5800):766-767
59.
BACKGROUND: The widespread acceptance of reduced‐tillage farming in cereal cropping systems in the Pacific Northwest of the United States has resulted in increased use of herbicides for weed control. However, soil residual concentrations of widely used imidazalone herbicides limit the cultivation of barley, which is more sensitive than wheat. In addition, increased severity of the root rot disease caused by Rhizoctonia solani is associated with reduction in tillage. Many crops exhibit altered disease responses after application of registered herbicides. In this study, the injury symptoms in barley caused by sublethal rates of two acetolactate synthase (ALS)‐inhibiting herbicides, imazamox and propoxycarbazone‐sodium, were assessed in factorial combinations with a range of inoculum concentrations of the root rot pathogen Rhizoctonia solani AG‐8. RESULTS: Both herbicides and pathogen had negative impacts on plant growth parameters such as root and shoot dry weight, shoot height and first leaf length, and interactions between pathogen and herbicide were detected. CONCLUSIONS: The results suggested that sublethal rates of herbicides and R. solani could alter severity of injury symptoms, possibly owing to the herbicide predisposing the plant to the pathogen. Copyright © 2012 Society of Chemical Industry 相似文献
60.
Alternatives to chemical dewormers are needed to counter anthelmintic resistance and improve worm control in organic management systems. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) compared with grass pastures for control of gastrointestinal nematodes (GIN) in lambs. In Experiment 1, Katahdin lambs grazed bermudagrass (BG; n=14), tall fescue (TF; n=7), or SL (n=19) pastures during early summer months. In Experiment 2, lambs grazed TF (n=15) or SL (n=13) pastures during late summer. Stocking rate of pastures was based on forage availability; additional lambs grazed pastures in Experiment 2, but were not sampled. Lambs were dewormed with 0.5 g COWP if FAMACHA(?) score was >3. In Experiment 1, FEC were reduced within 35 days in SL compared with BG lambs (forage by time, P=0.03). The PCV was more resilient to changes over time in SL compared with other groups of lambs (forage by time, P=0.001). In Experiment 2, FEC were lower (P=0.02) and PCV tended to be higher (P=0.09) in lambs grazing SL compared with TF forage. Incidence of deworming was similar among forage groups in both experiments. Grazing SL reduced FEC in lambs in early and late summer, despite reluctance by lambs to graze. Grazing forage and selective deworming using COWP was effective in lambs. 相似文献