全文获取类型
| 收费全文 | 440篇 |
| 免费 | 49篇 |
| 国内免费 | 2篇 |
专业分类
| 林业 | 10篇 |
| 农学 | 49篇 |
| 基础科学 | 2篇 |
| 67篇 | |
| 综合类 | 35篇 |
| 农作物 | 18篇 |
| 水产渔业 | 29篇 |
| 畜牧兽医 | 257篇 |
| 园艺 | 5篇 |
| 植物保护 | 19篇 |
出版年
| 2023年 | 6篇 |
| 2022年 | 3篇 |
| 2021年 | 10篇 |
| 2020年 | 11篇 |
| 2019年 | 14篇 |
| 2018年 | 24篇 |
| 2017年 | 17篇 |
| 2016年 | 13篇 |
| 2015年 | 8篇 |
| 2014年 | 23篇 |
| 2013年 | 38篇 |
| 2012年 | 13篇 |
| 2011年 | 18篇 |
| 2010年 | 22篇 |
| 2009年 | 21篇 |
| 2008年 | 21篇 |
| 2007年 | 24篇 |
| 2006年 | 15篇 |
| 2005年 | 8篇 |
| 2004年 | 17篇 |
| 2003年 | 13篇 |
| 2002年 | 12篇 |
| 2001年 | 9篇 |
| 2000年 | 13篇 |
| 1999年 | 7篇 |
| 1998年 | 23篇 |
| 1997年 | 14篇 |
| 1996年 | 15篇 |
| 1995年 | 12篇 |
| 1994年 | 5篇 |
| 1993年 | 5篇 |
| 1992年 | 10篇 |
| 1991年 | 6篇 |
| 1990年 | 3篇 |
| 1989年 | 4篇 |
| 1988年 | 3篇 |
| 1987年 | 1篇 |
| 1986年 | 1篇 |
| 1985年 | 1篇 |
| 1983年 | 1篇 |
| 1981年 | 2篇 |
| 1978年 | 1篇 |
| 1974年 | 1篇 |
| 1973年 | 3篇 |
排序方式： 共有491条查询结果，搜索用时 15 毫秒
491.
- The coastal marine protected ecosystem at Punta Coles (as a part of the Reserva Nacional de Islas, Islotes y Puntas Guaneras) is located in a highly exploited area in southern Peru and contains several commercial, bioengineering and other benthic species.
- Pre-image population analysis was used to estimate the transient values of intrinsic growth rate (r) based on biomass and density time series as a proxy of productivity to assess the effectiveness of protection.
- The outcomes obtained showed that the gastropods Concholepas concholepas, Fissurella latimartiginata and the tunicate Purya chilensis showed a reduction of productivity during recent years, whilst the sea urchin Loxechinus albus, the barnacle Balanus laevis and the bivalve Semimytilus algosus showed an opposite pattern. Several species exhibited a chaotic dynamic, coinciding with the highest productivity values. In 2016 and 2017, several species exhibited a reduction of their abundance which could be delayed responses explained by changes in oceanographic conditions (reduction of coastal upwelling), La Niña event and illegal harvest.
- The above notwithstanding, the results suggest that effective protection of benthic species in the protected ecosystem of Punta Coles have been partially accomplished. Therefore, this work could be considered a baseline study, permitting the subsequent monitoring of productivity of the main species inhabiting the coastal area of Punta Coles.
- Pre-image population analysis could be used as a complimentary analytical tool since it enables the evaluation of transient population parameters (e.g. productivity) thus aiding population management, conservation and monitoring decisions.