全文获取类型
| 收费全文 | 365篇 |
| 免费 | 22篇 |
| 国内免费 | 2篇 |
专业分类
| 林业 | 16篇 |
| 农学 | 39篇 |
| 基础科学 | 2篇 |
| 58篇 | |
| 综合类 | 65篇 |
| 农作物 | 9篇 |
| 水产渔业 | 14篇 |
| 畜牧兽医 | 157篇 |
| 园艺 | 10篇 |
| 植物保护 | 19篇 |
出版年
| 2023年 | 4篇 |
| 2022年 | 3篇 |
| 2021年 | 11篇 |
| 2020年 | 8篇 |
| 2019年 | 5篇 |
| 2018年 | 4篇 |
| 2017年 | 9篇 |
| 2016年 | 13篇 |
| 2015年 | 3篇 |
| 2014年 | 8篇 |
| 2013年 | 16篇 |
| 2012年 | 31篇 |
| 2011年 | 22篇 |
| 2010年 | 12篇 |
| 2009年 | 15篇 |
| 2008年 | 22篇 |
| 2007年 | 21篇 |
| 2006年 | 33篇 |
| 2005年 | 22篇 |
| 2004年 | 19篇 |
| 2003年 | 19篇 |
| 2002年 | 21篇 |
| 2001年 | 7篇 |
| 2000年 | 2篇 |
| 1999年 | 3篇 |
| 1998年 | 1篇 |
| 1997年 | 4篇 |
| 1996年 | 3篇 |
| 1995年 | 3篇 |
| 1994年 | 6篇 |
| 1993年 | 2篇 |
| 1992年 | 4篇 |
| 1991年 | 7篇 |
| 1990年 | 6篇 |
| 1989年 | 2篇 |
| 1988年 | 2篇 |
| 1987年 | 2篇 |
| 1986年 | 1篇 |
| 1985年 | 3篇 |
| 1984年 | 1篇 |
| 1982年 | 1篇 |
| 1981年 | 1篇 |
| 1980年 | 1篇 |
| 1979年 | 1篇 |
| 1977年 | 1篇 |
| 1975年 | 1篇 |
| 1974年 | 1篇 |
| 1970年 | 1篇 |
| 1966年 | 1篇 |
排序方式： 共有389条查询结果，搜索用时 62 毫秒
71.
Melon collapse caused by the heat-tolerant soil-borne fungus Monosporascus cannonballus is not controlled by current solarization technology applied to large soil volumes because the temperatures achieved are not high enough to kill the pathogen's ascospores. The efficacy of improved solarization achieved by mulching a shallow layer of growth medium in containers was studied in terms of disease control and yield increase over two growing seasons. Compared to solarization of a regular container, solarization of a shallow layer (5–6 cm) of growth medium resulted in a 3–5°C elevation in maximal temperature at a depth of 3 cm, and in a 7–10°C increases at the bottom of the shallow layer. This led to a higher disease reduction and higher yields in the 1996 experiment. In 1997, both methods of solarization were highly effective. Yield was highly correlated with disease reduction in both experiments. In the 1997 experiment, ascospore viability declined faster in the shallow container treatment than in the regular container. This study demonstrates the potential of an additional approach for improving solarization of containerized plant growth medium and improving its reliability, with the aim of controlling heat-tolerant pathogens. 相似文献
72.
John G. Howieson Robert J. Harrison Ron J. Yates Belinda Hackney Angelo Loi Brad J. Nutt 《Grass and Forage Science》2021,76(1):82-92
The patterns and extent of hard seed breakdown of dormant seeds and pods following burial in the soil in February (summer) varied for up to 19 accessions of 12 species of annual forage legumes. The experiments, at six sites across southern Australia, were designed to identify legumes whose patterns of hard seed breakdown would suit them to agronomic evaluation in a summer sowing research program. For a subset of accessions, sufficient hard seed breakdown was demonstrated between February and April to allow a high proportion of seed to germinate in late autumn—a desirable pattern for summer sowing. Although there was a large G x E interaction, some cultivars of Ornithopus sativus Brot., O. compressus L. and Trifolium spumosum L. had a pattern that was reproducible at all sites. The experiments also identified accessions of Biserrula pelecinus L. and T. glanduliferum Boiss., which had the desirable pattern in regions of south‐eastern Australia, but not Western Australia. A pragmatic approach for selection of forage legume accessions in situ for evaluation within a summer sowing program was demonstrated. 相似文献
73.
An overview of the current European legislation concerning animal welfare is given. The legal requirements concern the housing and care of production animals (poultry, calves and swine), the transport of animals and the killing of animals (not only in slaughterhouses, but also in case of contagious animal disease outbreaks). General information concerning the principles and contents of European pieces of legislation as well as detailed information concerning requirements for individual animal species is given. Furthermore, other elements concerning animal welfare such as castration of piglets, ritual slaughter and animals used for experimental purposes are also reviewed. Finally, some recent initiatives in the field of animal welfare are mentioned and useful links are provided for finding the various legislative acts and additional supportive information. 相似文献
74.
75.
76.
77.
Rangelands and hayfields provide a large portion of remaining surrogate habitat for many species of declining grassland birds in North America. We compared late-cut hayfields and continuously grazed pastures at low to moderate cattle densities for providing suitable breeding habitat in eastern Canada for the nationally threatened Bobolink (Dolichonyx oryzivorus). To examine the quality of both habitats, we conducted point counts and monitored 87 nests during the 2015 and 2016 breeding seasons. Bobolink abundance and daily survival rate (DSR) of nests were modeled sequentially by habitat and sex as a function of vegetation structure, prey availability, and agricultural management. Year and habitat were the strongest predictors of abundance. When analyzed separately for pastures and hayfields, vegetation height was most important for female abundance in pastures while pasture size was most important for males. Nests in hayfields had significantly higher daily survival (DSR = 0.98 ± 0.01) than nests in pastures (DSR = 0.94 ± 0.01). Nesting success was highest in hayfields with taller vegetation, while in pastures, no microhabitat variable showed a clear relationship with DSR. Within pastures, cattle stocking densities of ≤ 1 animal units (AU) · ha? 1 were not related to DSR. This study provides evidence that late-cut hay is of highest quality, but that small-scale beef farms with low to moderate stocking densities are suitable targets for conservation efforts of Bobolinks in eastern North America. 相似文献
78.
79.
Darren R. Grafius Ron Corstanje Philip H. Warren Karl L. Evans Steven Hancock Jim A. Harris 《Landscape Ecology》2016,31(7):1509-1522
Context
Urbanisation places increasing stress on ecosystem services; however existing methods and data for testing relationships between service delivery and urban landscapes remain imprecise and uncertain. Unknown impacts of scale are among several factors that complicate research. This study models ecosystem services in the urban area comprising the towns of Milton Keynes, Bedford and Luton which together represent a wide range of the urban forms present in the UK.Objectives
The objectives of this study were to test (1) the sensitivity of ecosystem service model outputs to the spatial resolution of input data, and (2) whether any resultant scale dependency is constant across different ecosystem services and model approaches (e.g. stock- versus flow-based).Methods
Carbon storage, sediment erosion, and pollination were modelled with the InVEST framework using input data representative of common coarse (25 m) and fine (5 m) spatial resolutions.Results
Fine scale analysis generated higher estimates of total carbon storage (9.32 vs. 7.17 kg m?2) and much lower potential sediment erosion estimates (6.4 vs. 18.1 Mg km?2 year?1) than analyses conducted at coarser resolutions; however coarse-scale analysis estimated more abundant pollination service provision.Conclusions
Scale sensitivities depend on the type of service being modelled; stock estimates (e.g. carbon storage) are most sensitive to aggregation across scales, dynamic flow models (e.g. sediment erosion) are most sensitive to spatial resolution, and ecological process models involving both stocks and dynamics (e.g. pollination) are sensitive to both. Care must be taken to select model data appropriate to the scale of inquiry.80.
Garrett M. Street John Fieberg Arthur R. Rodgers Michelle Carstensen Ron Moen Seth A. Moore Steve K. Windels James D. Forester 《Landscape Ecology》2016,31(9):1939-1953