全文获取类型
收费全文 | 810篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 11篇 |
废物处理 | 31篇 |
环保管理 | 60篇 |
综合类 | 183篇 |
基础理论 | 167篇 |
污染及防治 | 254篇 |
评价与监测 | 62篇 |
社会与环境 | 47篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 10篇 |
2022年 | 32篇 |
2021年 | 19篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 29篇 |
2017年 | 32篇 |
2016年 | 49篇 |
2015年 | 18篇 |
2014年 | 49篇 |
2013年 | 59篇 |
2012年 | 37篇 |
2011年 | 67篇 |
2010年 | 34篇 |
2009年 | 31篇 |
2008年 | 44篇 |
2007年 | 43篇 |
2006年 | 39篇 |
2005年 | 28篇 |
2004年 | 31篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1966年 | 2篇 |
1965年 | 3篇 |
1964年 | 5篇 |
1963年 | 4篇 |
1962年 | 2篇 |
1961年 | 4篇 |
1960年 | 5篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1957年 | 5篇 |
1942年 | 2篇 |
1941年 | 2篇 |
排序方式: 共有820条查询结果,搜索用时 203 毫秒
221.
Transient effect of the herbicide flazasulfuron on carbohydrate physiology in Vitis vinifera L 总被引:1,自引:0,他引:1
In the Champagne vineyard, most of the areas treated in early 2000 with the newly approved herbicide flazasulfuron had vines with altered growth and yellow leaves throughout the growing season. In order to clarify the physiological perturbations caused on the non-target grapevine and their potential consequences, C nutrition of grape plants grown in vineyards treated or not with flazasulfuron in 2000 was characterized during the following season. Vines from treated areas exhibited yellow leaves and an alteration of photosynthetic activity, characterized by declines in leaf gas exchanges (by 85%) and photosynthetic pigment concentrations (by 88%), and a marked disorganization of the leaf plastids. The herbicide also caused a decrease in leaf starch and soluble carbohydrate levels (-74% and -90%, respectively). Surprisingly, some vines re-greened after bloom, then exhibiting similar carbohydrate physiology to those grown in a non-treated area. Thus, recovery of CO(2) fixation rates, plastid ultra-structure, pigment concentrations and carbohydrate levels was found in re-greening leaves. Unlike the informations available in the literature, our results showed that flazasulfuron may be phytotoxic for grapevine. However, this toxicity was overcome the following year, indicating that vines have the potential to recover from this herbicide stress after one season. 相似文献
222.
Mathilde Stomp Maël Leroux Marjorie Cellier Séverine Henry Martine Hausberger Alban Lemasson 《Die Naturwissenschaften》2018,105(9-10):57
While the vocal coding of human and animal internal states has been widely studied, the possible acoustic expression of “positive” emotions remains poorly known. Recent studies suggest that snorts (non-vocal sounds produced by the air expiration through the nostrils) appear to be reliable indicators of positive internal states in several ungulate species. Here, we hypothesised in horses that the acoustic structure of the snort could vary with the subjects’ current emotional state. Indeed, a preliminary sound analysis of snorts let us suggest structure variations related to the presence of pulsations. We recorded snorts from 20 horses living in a riding center. Auditory playbacks run with 20 humans first confirmed the existence of two snort subtypes, i.e. one pulsed and one non-pulsed. Observations were then conducted to compare the distribution of these two subtypes according to the location (stall/pasture) of the signaller as a contextual determinant of its internal state and to its ears’ position as a reflection of its emotional state. We found that both subtypes were preferentially observed in positive contexts, but that pulsed snorts were even more associated with highly appreciated situations (in pasture and with ears forward). This study is a step further in the identification of indicators of positive emotions in horses and more generally in the understanding of the acoustic emotions’ coding. 相似文献
223.
224.
225.
226.
227.
228.
Delphine Nicolas Aurélie Chaalali Hilaire Drouineau Jérémy Lobry Ainhize Uriarte Angel Borja Philippe Boët 《Regional Environmental Change》2011,11(3):639-649
The aim of this study was to determine whether the latitudinal distribution of fish species that use estuaries to complete
their entire life cycle has shifted northward as an expected consequence of global warming. The mean latitude of past fish
species distributions found in 1970s’ literature was compared with the mean latitude of distributions today based on fish
density indices collected in 55 tidal estuaries along the Atlantic European seaboard, from Portugal to Scotland. Among the
15 most common species, 11 displayed a positive difference between current and past mean latitudes suggesting a northward
shift of the populations. Using the occurrence of subtropical species in temperate areas as an indicator of water warming,
the northernmost range limit of 10 subtropical species was subsequently focused on. Six of them were recorded up to their
past northern latitudinal limit. These results reinforced the idea that a number of fish species associated to estuaries have
migrated northwards over the last 30 years, possibly due to water warming. These ecological changes can get important managerial
implications, i.e. in the assessment of the ecological status in European directives. 相似文献
229.
230.
Water allocation systems are challenged by hydrologic droughts, which reduce available water supplies and can adversely affect human and environmental systems. To address this problem, drought management mechanisms have been instituted in jurisdictions around the world. Historically, these mechanisms have involved a crisis management or reactive approach. An important trend during the past decade in places such as the United States has been a shift to a more proactive approach, emphasizing drought preparedness and local involvement. Unfortunately, local capacity for drought planning is highly variable, with some local governments and organizations proving to be more capable than others of taking on new responsibilities. This paper reports on a study of drought planning and water allocation in the State of Minnesota. Factors facilitating and constraining local capacity for drought planning were identified using in-depth key informant interviews with state officials and members of two small Minnesota cities, combined with an analysis of pertinent documentation. A key factor contributing to the effectiveness of Minnesota's system is a water allocation system with explicit priorities during shortages, and provisions for restrictions. At the same time, the requirement that water suppliers create Public Water Supply Emergency Conservation Plans (PWSECP) clarifies the roles and responsibilities of key local actors. Unfortunately, the research revealed that mandated PWSECP are not always implemented, and that awareness of drought and drought planning measures in general may be poor at the local level. From the perspective of the two cities evaluated, factors that contributed to local capacity included sound financial and human resources, and (in some cases) effective vertical and horizontal linkages. This analysis of experiences in Minnesota highlights problems that can occur when senior governments establish policy frameworks that increase responsibilities at the local level without also addressing local capacity. 相似文献