全文获取类型
收费全文 | 400篇 |
免费 | 16篇 |
专业分类
林业 | 1篇 |
4篇 | |
综合类 | 24篇 |
农作物 | 2篇 |
水产渔业 | 1篇 |
畜牧兽医 | 378篇 |
园艺 | 1篇 |
植物保护 | 5篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 9篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 13篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 24篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 9篇 |
2009年 | 17篇 |
2008年 | 23篇 |
2007年 | 28篇 |
2006年 | 20篇 |
2005年 | 18篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 16篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 11篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有416条查询结果,搜索用时 62 毫秒
411.
412.
413.
414.
Diffusing-wave spectroscopy was used to measure the microscopic dynamics of grains in the interior of a three-dimensional flow of sand. The correlation functions show that minutely separated grains fly from collision to collision with large random velocities. On a time scale 10(3) to 10(4) times longer than the average time between collisions, the grains displayed slow, collective rearrangements, which, at the long-time limit, produced diffusive dynamics. 相似文献
415.
Virus-free clones were developed from meristem tips of five selections of Netted Gem (Russet Burbank) potato which had been grown separately for at least 40 years. During three years of comparative trials, plant and tuber characteristics of the five clones were identical. There were no significant differences in total yield. Differences in marketable yield and, tuber set were few and inconsistent. 相似文献
416.
A new strategic inventory across all publicly managed forests has been installed in Victoria. For the preceding two decades, Victoria’s forest inventory has been compiled from various data sources from across the state, an approach that doesn’t allow information about the nature and rate of changes to the resource to be estimated, or for projections or forecasts to be made. To address these limitations, the Victorian Forest Monitoring Program (VFMP) was established, to monitor Victoria’s progress in meeting a commitment towards sustainable forest management, and to satisfy requirements for state and national reporting. The purpose of the new program is to ‘assess and monitor the extent, state and sustainable development of Victoria’s public forests in a timely and accurate manner.’ The VFMP consists of a plot-based system of permanent observational units located on a state-wide grid. A combination of ground-based and aerial photo plots and remotely sensed data are used to capture a set of basic attributes that are used to derive indicators of sustainability. To meet the monitoring needs a remeasurement framework has been developed to guide the change estimation procedures. The program was designed and implemented between 2009 and 2015 and used to generate data and information for the most recent Victoria’s State of the Forest Report. The first annual change estimate is due to be completed in 2017. A summary of implementation and proposed maintenance is presented and discussed in this paper. 相似文献