全文获取类型
收费全文 | 1296篇 |
免费 | 105篇 |
国内免费 | 56篇 |
专业分类
林业 | 160篇 |
农学 | 51篇 |
基础科学 | 11篇 |
188篇 | |
综合类 | 454篇 |
农作物 | 40篇 |
水产渔业 | 126篇 |
畜牧兽医 | 326篇 |
园艺 | 38篇 |
植物保护 | 63篇 |
出版年
2024年 | 8篇 |
2023年 | 15篇 |
2022年 | 30篇 |
2021年 | 43篇 |
2020年 | 41篇 |
2019年 | 39篇 |
2018年 | 31篇 |
2017年 | 58篇 |
2016年 | 47篇 |
2015年 | 55篇 |
2014年 | 56篇 |
2013年 | 82篇 |
2012年 | 94篇 |
2011年 | 114篇 |
2010年 | 97篇 |
2009年 | 88篇 |
2008年 | 87篇 |
2007年 | 85篇 |
2006年 | 71篇 |
2005年 | 57篇 |
2004年 | 45篇 |
2003年 | 35篇 |
2002年 | 31篇 |
2001年 | 23篇 |
2000年 | 30篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1986年 | 1篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有1457条查询结果,搜索用时 15 毫秒
31.
B Genz J Gerszon Y Pollock B Gleeson R Shankar MJ Sellars RJ Moser 《Australian veterinary journal》2023,101(4):153-163
Rotaviruses (RV) have a high prevalence in piggeries worldwide and are one of the major pathogens causing severe diarrhoea in young pigs. RV species A, B, and C have been linked to piglet diarrhoea in Australian pig herds, but their genetic diversity has not been studied in detail. Based on sequencing of the structural viral protein 7 (VP7) RVA G genotypes G3, G4 and G5, and RVC types G1, G3, G5, and G6 have been identified in Australian piggeries in previous studies. Although occurrence of RVB was reported in Australia in 1988, no further genetic analysis has been conducted. To improve health management decisions in Australian pig herds, more information on RV prevalence and genetic diversity is needed. Here, 243 enteric samples collected from 20 pig farms within Eastern Australia were analysed for the presence of RV in different age groups using a novel PCR-based multiplex assay (Pork MultiPath™ enteric panel). RVA, RVB, and RVC were detected in 10, 14, and 14 farms, respectively. Further sequencing of VP7 in selected RV-positive samples revealed G genotypes G2, G5, G9 (RVA), G6, G8, G14, G16, G20 (RVB), and G1, G3, G5, G6 (RVC) present. RVA was only detected in young (<10 weeks old) pigs whereas RVB and RVC were also detected in older animals (>11 weeks old). Interestingly, RVB and RVC G-type occurrence differed between age groups. In conclusion, this study provides new insights on the prevalence and diversity of different RV species in pig herds of Eastern Australia whilst demonstrating the ability of the Pork MultiPath™ technology to accurately differentiate between these RV species. 相似文献
32.
园林是在一定的空间里依照园林艺术原则,进行创作而形成自然美与人工美相融合的生活境域。本文从三大方面论述了中西方园林艺术的不同及历史上的相互交流与影响,希望对我们有所启发。 相似文献
33.
Heath TJ 《Australian veterinary journal》2008,86(9):357-364
Objective To describe the location, type, support from and effects of their first position for the veterinary graduates of 2005, and to make comparisons with graduates of 1950-2000. Procedure Questionnaires were sent to veterinarians who had graduated from an Australian university in 2005, and data were analysed with SAS System 8 for Windows. Results One-sixth of the graduates left for overseas, and 55% (Murdoch) to 85% (Melbourne) of the remainder found their first veterinary position in the state where they were trained. More were in small animal (48%) and less in mixed practice (48%) than in previous decades, and they spent more time (79%) with dogs and cats, and less with horses (9%), cattle (8%) and other production animals (1%). The median income of males working full-time was $43,000 and $39,000 for equivalent females. Most were satisfied with the help and support received from their boss and workplace; approximately 20% felt that support was inadequate, and many felt overworked and underpaid. The graduates with inadequate support were more likely to suffer stress and were less likely to have enjoyed their first year or to agree that they would become a veterinarian again. The levels of perceived support, and of stress, were similar to those reported by graduates of 2000, though more favourable than in the previous 2 decades. Conclusions Graduates of 2005 were less likely than their predecessors to start in mixed practice or to work with cattle and horses. Most felt poorly paid, but most, though not all, felt well supported in their first position. Aust Vet J 2008;86:357-364. 相似文献
34.
Kyasanur forest disease virus breaking the endemic barrier: An investigation into ecological effects on disease emergence and future outlook 下载免费PDF全文
Kyasanur Forest disease (KFD) is found in a limited range of India, but is epidemiologically understudied. The seasonal patterns of KFD are well known; however, the significant concern is on the extent to which changes in epidemiology happen especially under the influence of ecological destructions and by the eventual effects of resulting climate change. Presently, a southward and northward spread of the Kyasanur Forest disease virus (KFDV) along the Western Ghats has been reported in the adjoining states of Kerala, Tamil Nadu, Goa and Maharashtra. In this review, we investigate the cascade of factors that might have facilitated the resurgence of KFDV among the endemic regions in higher frequency and its recent emergence in the area previously not reported. Utilizing published data, we additionally endeavour to exhibit a portion of the impediments of control systems and embody the powerful option strategies for developing KFDV control. 相似文献
35.
[目的]川西平原秋季多绵雨,为避开播种期湿害影响,筛选适合川西平原生态区免耕晚直播的甘蓝型双低油菜新品种。[方法]以10个甘蓝型油菜新品种为试材,采用随机区组排列,3次重复,免耕晚直播,稻草覆盖,进行比较试验。[结果]‘川油58’、‘华油杂10号’和‘宁杂11号’产量高,折合单产3 000 kg/hm2以上,综合性状表现较好、生育期短、抗性好、品质优;‘华油杂13号’和‘浙双3号’有高产潜力,单产2 775 kg/hm2以上,抗性好、品质优、生育期适中;其他品种较对照减产极显著、综合性状表现较差,抗性较差。[结论]‘华油杂10号’、‘宁杂11号’、‘华油杂13号’和‘浙双3号’等长江中下游优异品种可以成功引种并在川西平原进行大面积推广种植。 相似文献
36.
以社会成员对公共体育服务的需求为切入点,采用文献资料、访谈、问卷调查和数理统计等研究方法对贵州省公共体育服务的基础设施类、信息服务类、要素保障类进行调查分析,探讨西部欠发达地区公共体育服务体系的构建。 相似文献
37.
38.
- 1. Surrogates aim to predict species diversity and to minimize sampling effort. Here the value of surrogates for marine macroalgae is tested.
- 2. Higher taxonomic levels and dominant taxa were evaluated as surrogates for detecting patterns in macroalgal species diversity (derived from species‐level biomass data) in the Recherche Archipelago, Western Australia.
- 3. Data were stratified by two island groups (inshore and offshore), three depth intervals (<10 m, 10–20 m, >20 m), and two exposures to wave energy. Correlations between similarity matrices from surrogate and species diversity data matrices were analysed using a modified Spearman rank correlation (rs). The ability of surrogates to detect differences between exposures to wave energy was also investigated using analysis of similarity. Species diversity data were aggregated to higher taxonomic levels and were either fourth‐root or presence/absence (richness) transformed.
- 4. Species richness was the most consistent surrogate (rs‐values>0.69, P=0.001). Genus‐level richness was also strongly correlated to species diversity in the Recherche Archipelago, except in depths <10 m where patterns in diversity were characterized by species turnover.
- 5. At offshore islands in depths 10–20 m and >20 m, family‐ and order‐level biomass data were suitable surrogates owing to the abundance of Alariaceae (Order Laminariales) represented by a single genus and species. Surrogates using biomass data from the orders Laminariales, Ceramiales, Dictyotales and Fucales were also successful at offshore islands in middle to deeper depths.
- 6. At inshore islands in depths 10–20 m and >20 m, genera from the orders Gigartinales, Fucales and Ceramiales were strongly correlated to species biomass data.
- 7. Surrogates, like species richness, that were strongly correlated to species biomass data were also able to distinguish between exposures to wave energy, based on analysis of similarity tests.
- 8. Sampling effort would be reduced if collecting richness data in species‐rich macroalgal assemblages such as those found in temperate Australia.
39.
根据中西太平洋1984~2003年金枪鱼围网渔业的渔获量统计资料,利用G IS定性分析方法和数值分析方法对中西太平洋海区的金枪鱼围网渔场的时空变动进行研究。研究结果表明:1984年到1991年,CPUE值在12.0~17.3 t/(d.n)之间;1992年至2003年,CPUE值在19.1~27.9 t/(d.n)之间,两个阶段的CPUE差异显著;Ⅰ、Ⅱ和Ⅲ类渔场基本上全部分布在5°S~5°N、140°E~180°之间,但Ⅲ类渔场在南半球略往东延伸,在10~5°S、155°~160°E之间也有分布;Ⅳ、Ⅴ类渔场则分布在Ⅰ、Ⅱ和Ⅲ类渔场的周边,其中Ⅳ类渔场主要位于东经地区,Ⅴ类渔场主要位于西经地区。 相似文献
40.
随着社会经济的飞速发展,培养学生职业能力的重要性日益突出。当前"西方经济学"课程教学存在着课程实验内容的不足、教学活动创新性不够、教学主体参与性不强以及分析方法缺乏归纳和整理等问题,对学生专业实践、职业转换、社会交往、综合运用方面的能力培养造成不利影响,因而需要合理规划与选择,以培养出社会所需的"一专多能"的人才。 相似文献