全文获取类型
收费全文 | 1549篇 |
免费 | 12篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 26篇 |
废物处理 | 48篇 |
环保管理 | 91篇 |
综合类 | 865篇 |
基础理论 | 219篇 |
环境理论 | 2篇 |
污染及防治 | 235篇 |
评价与监测 | 48篇 |
社会与环境 | 29篇 |
灾害及防治 | 3篇 |
出版年
2018年 | 15篇 |
2017年 | 24篇 |
2015年 | 20篇 |
2014年 | 17篇 |
2013年 | 54篇 |
2012年 | 47篇 |
2011年 | 41篇 |
2010年 | 34篇 |
2009年 | 41篇 |
2008年 | 31篇 |
2007年 | 38篇 |
2006年 | 42篇 |
2005年 | 38篇 |
2004年 | 44篇 |
2003年 | 42篇 |
2002年 | 35篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 15篇 |
1998年 | 18篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1989年 | 11篇 |
1985年 | 12篇 |
1967年 | 12篇 |
1966年 | 16篇 |
1965年 | 23篇 |
1964年 | 23篇 |
1963年 | 31篇 |
1962年 | 26篇 |
1961年 | 19篇 |
1960年 | 29篇 |
1959年 | 29篇 |
1958年 | 21篇 |
1957年 | 21篇 |
1956年 | 19篇 |
1955年 | 31篇 |
1954年 | 44篇 |
1953年 | 20篇 |
1952年 | 18篇 |
1951年 | 24篇 |
1948年 | 11篇 |
1947年 | 11篇 |
1942年 | 11篇 |
1939年 | 14篇 |
1938年 | 14篇 |
1933年 | 11篇 |
1931年 | 15篇 |
1930年 | 12篇 |
1929年 | 14篇 |
排序方式: 共有1566条查询结果,搜索用时 328 毫秒
161.
Summary. Host plant volatiles may be involved in the sexual communication of insects in several ways. In the pheromone-producing sex, these volatiles may affect pheromone production or release and, in the receptive sex, plant volatiles may have a synergistic effect on the attraction to sex pheromone. We conducted three types of experiments to determine if and how plant volatiles are involved in the sexual communication of Lygocoris pabulinus (L.) (Heteroptera: Miridae), the females of which attract males. In a one-choice cylinder bioassay, females were offered to males on two different plants, belonging to different plant families, i.e. potato leaves and goosefoot leaves, to determine if specific plant volatiles were involved in the attraction of males towards females. Females on potato leaves were as attractive as females on goosefoot leaves, but significantly more attractive than females without plant material. The latter result suggests an interaction between females and potato leaves. However, in two-choice flying and walking bioassays, using delta traps in a wind tunnel and a vertical Y-track olfactometer, males were attracted to females irrespective of the presence of potato leaves. This difference in result is probably due to the fact that in the latter assays females were confined with pollen as an alternative food source, while females in the one-choice assay had access to water only, so that they may have suffered from malnutrition. Males in the one-choice assay were also attracted to potato leaves from which females had been removed, indicating that attractive components from females are deposited and adsorbed to the substrate. Plants are probably only indirectly involved in sexual communication, their surface merely functioning as a substrate from which pheromone is released. Males may subsequently be attracted to such plants or substrates. Clean plant material was not attractive to L. pabulinus males, hence plant volatiles alone do not seem to be used by these males as possible mate location cues. 相似文献
162.
163.
164.
165.
166.
Yoram Krozer Sharon Hophmayer-Tokich Hans van Meerendonk Simon Tijsma Eric Vos 《Journal of Cleaner Production》2010,18(5):439-446
Innovations in water chain are discussed based on experiences in the Netherlands. The available and new technological options, as well as their dissemination in the Netherlands, are presented for the prevailing system with add-on technologies (elongation), and for the emerging separation system with technologies at the source. Numerous new options are available for both systems but these options are rarely used. The low use is explained using economic theories and with practical examples from the Netherlands. In order to foster innovations, the mainstream, evolutionary, and behavioral theories pinpoint respectively the pricing of common goods, broad support of concerted action, and support for innovators’ entry. These actions may all be needed. Experiences with a stakeholder cluster in water management suggest that markets for high value water use invoke innovations and low-cost technology adaptations. The systematic development of services that foster high value water-based activities is recommended. 相似文献
167.
168.
169.
170.
The role of natural disaster in individual and relational adjustment in Sri Lankan mothers following the 2004 tsunami
下载免费PDF全文
![点击此处可从《Disasters》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alyssa Banford David C. Ivey Thulitha Wickrama Judith Fischer Anne Prouty Douglas Smith 《Disasters》2016,40(1):134-157
The purpose of this study is to examine the associations between maternal mental health distress symptoms, including depression and post‐traumatic stress disorder, the extent to which the presence of a child's disaster‐related physical health problem(s) have interfered with daily functioning, and family cohesion over time among Sri Lankan mothers who survived the tsunami on 26 December 2004. Study variables were measured using a self‐report questionnaire administered approximately four months after the event and three years later in summer 2008. Univariate, bivariate, and multivariate analyses were conducted. Path analysis was employed to assess the relationships between the key variables over time and the correlations in the study variables at each time point. Among other findings, the results of the path analysis indicated that post‐traumatic stress symptom distress four months after the disaster significantly predicted variance in family cohesion three years later. Clinical and empirical research implications are presented and discussed. 相似文献