全文获取类型
收费全文 | 546篇 |
免费 | 3篇 |
专业分类
安全科学 | 27篇 |
废物处理 | 5篇 |
环保管理 | 142篇 |
综合类 | 76篇 |
基础理论 | 215篇 |
环境理论 | 4篇 |
污染及防治 | 25篇 |
评价与监测 | 13篇 |
社会与环境 | 22篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 27篇 |
2015年 | 14篇 |
2014年 | 16篇 |
2013年 | 25篇 |
2012年 | 4篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 53篇 |
2008年 | 48篇 |
2007年 | 42篇 |
2006年 | 43篇 |
2005年 | 22篇 |
2004年 | 21篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有549条查询结果,搜索用时 656 毫秒
381.
J.?Antonio?Baeza Raymond?T.?BauerEmail author 《Behavioral ecology and sociobiology》2004,55(6):544-550
In Lysmata wurdemanni, individuals begin benthic life in a male phase (MP) but later change to a female phase (FP) with female external morphology, but with both male and female reproductive capacity (protandric simultaneous hermaphroditism). Previous studies have demonstrated that the size (timing) of sex change varies considerably in natural populations. We experimentally tested for social mediation of sex change by rearing male-phase individuals (MPs) in both large and small social groups with different sexual and size composition. In the large group experiment, speed of sex change was inversely related to the abundance of female-phase individuals (FPs) in the group (sex-ratio induction). Increased allocation to female function (more rapid change to FP) may occur when male mating opportunities are lower because the simultaneous-hermaphrodite FP can immediately reproduce as a female while maintaining male mating capacity. When FPs are abundant, delayed sex change might be adaptive because the costs of female reproduction are considerable. An MP may gain reproductively by increased growth before changing to FP at a larger size (fewer but much larger broods). Size-ratio induction of sex change by small MPs was suggested but not confirmed. Experimental results from small groups (1–2 individuals) were qualitatively similar but not as conclusive as those from large groups. The number and complexity of social interactions in large groups may be necessary to stimulate labile sex change in this species. In L. wurdemanni, sex change may be influenced not only by abiotic factors related to breeding [Bauer (2002) Biol Bull 203:347–357] but also by social factors in certain demographic situations.Communicated by K. Lindström 相似文献
382.
Vicarious sampling: the use of personal and public information by starlings foraging in a simple patchy environment 总被引:6,自引:0,他引:6
Group foragers may be able to assess patch quality more efficiently by paying attention to the sampling activities of conspecifics
foraging in the same patch. In a previous field experiment, we showed that starlings foraging on patches of hidden food could
use the successful foraging activities of others to help them assess patch quality. In order to determine whether a starling
could also use another individual’s lack of foraging success to assess and depart from empty patches more quickly, we carried
out two experimental studies which compared the behaviour of captive starlings sampling artificial patches both when alone
and when in pairs. Solitary starlings were first trained to assess patch quality in our experimental two-patch system, and
were then tested on an empty patch both alone and with two types of partner bird. One partner sampled very few holes and thus
provided a low amount of public information; the other sampled numerous holes and thus provided a high amount of public information.
In experiment 1, we found no evidence of vicarious sampling. Subjects sampled a similar number of empty holes when alone as
when with the low and high information partners; thus they continued to rely on their own personal information to make their
patch departure decisions. In experiment 2, we modified the experimental patches, increasing the ease with which a bird could
watch another’s sampling activities, and increasing the difficulty of acquiring accurate personal sampling information. This
time, subjects apparently did use public information, sampling fewer empty holes before departure when with the high-information
partner than when with the low-information partner, and sampling fewer holes when with the low-information partner than when
alone. We suggest that the degree to which personal and public information are used is likely to depend both on a forager’s
ability to remember where it has already sampled and on the type of environment in which foraging takes place.
Received: 31 January 1995/Accepted after revision: 11 September 1995 相似文献
383.
Christine Errard Francisca Ruano Freddie-Jeanne Richard Alain Lenoir Alberto Tinaut Abraham Hefetz 《Chemoecology》2006,16(4):235-240
Summary. Proformica longiseta exists as two populations in the Sierra Nevada Mountains in Spain, only one of which is parasitized by the slave-maker ant
Rossomyrmex minuchae. To investigate the possible effect of co-evolutionary pressures on cuticular hydrocarbon (CHC) profiles (the presumed nestmate
recognition cues), we performed a comparative analysis of the CHC of R. minuchae and P. longiseta colonies from both the allopatric and sympatric populations; the latter includes samples of enslaved as well as free-living
workers. Discriminant analyses based on these chemical profiles showed two clear profile groups: the first comprised R. minuchae and both enslaved and free-living P. longiseta from the sympatric population; and the second the allopatric P. longiseta workers. As expected, the profiles of the two sympatric P. longiseta groups (enslaved and free-living) were distinct; but, interestingly, those of the enslaved P. longiseta and its parasite R. minuchae were also distinguishable. This indicates that despite their cohabitation each species maintains its own chemical identity.
Profile similarity between the sympatric free-living P. longiseta and its parasite may explain the lower than expected aggression observed during raids. We further speculate that in view
of the differences between the sympatric and allopatric population of P. longiseta, co-evolutionary pressures have driven changes in the profile of the former to better match that of its parasite R. minuchae. Such an adjustment may have enabled nests of the sympatric P. longiseta to endure multiple raids by the parasite (due to the reduced aggression) and thus to continue to reproduce despite the damage
inflicted by the raids. 相似文献
384.
This paper presents research currently being conducted in Central Queensland, Australia to understand conflicts between coastal
zone resource users and the associated sociocultural and political issues surrounding coastal zone management. Conflict occurs
between stakeholders in the coastal zone over values, conservation and development trade-offs, access, and resource use rights.
Decisions are currently made within a multi-stakeholder framework where there is limited understanding among stakeholders
of each groups values and aspirations, and few, mechanisms for negotiation, or to ensure transparency of decisions and feedback
on consultation. This paper reports on the contribution of stakeholder analysis and social mapping to conflict management
and findings from their application. As it is applied here, stakeholder analysis and social mapping have been successful participatory
tools used to document and feed back the values, interests, attitudes and aspirations of stakeholders. Understanding stakeholder
conflict is essential in progressing a whole catchment approach to decision-making that secures the cooperation of a diverse
range of social groups. 相似文献
385.
Many animals, including gregarious caterpillars, begin life in groups and become increasingly solitary as they grow larger. These ontogenetic changes in social behaviour suggest that the costs and benefits of grouping change with increasing individual size. Forest tent caterpillar (Malacosoma disstria) colonies exhibit complex social behaviour during the early larval instars, using pheromone trails to move together between temporary bivouacs and feeding sites, and break up as the caterpillars grow. We demonstrate changes in individual responses to cues from conspecifics that explain changes in aggregation during caterpillar development. We used Markov chain analysis to test the influence of pheromone trails and colony-mates on an individual caterpillars tendency to switch between quiescence, searching, walking and spinning. Pheromone-laden silk trails increased the tendency to begin locomotion, whereas colony-mates increased switching from activity to quiescence. Trails also influenced the form taken by locomotor behaviour, and promoted directed walking over searching. Social cues thus increase the efficiency of individual locomotion. Younger larvae were more quiescent and more reluctant to walk in the absence of trails than were older insects. An increase in independent locomotion as the larvae grow provides a mechanism to explain colony break-up and points to an ontogenetic shift in the internal processes driving behaviour. Scaling relationships suggest that many of the benefits associated with group-living in caterpillars decrease as individuals grow larger, providing an adaptive explanation for observed ontogenetic changes in social behaviour.Communicated by N. Wedell 相似文献
386.
Mark Sagoff 《Environmental management》1996,20(6):897-911
This paper describes two frameworks—utilitarian and Kantian—society uses to make decisions concerning environmental management and, in particular, species protection. The utilitarian framework emphasizes the consequences of choices for prior preferences. A perfectly competitive market, on this model, correctly values environmental resources. The Kantian approach identifies rules appropriate to recognized situations given the identity of the decision maker. It relies on democratic political processes and institutions to provide the means by which citizens determine the identity of their community—its moral character and aspirations—and match appropriate rules to recognized situations. This paper argues that markets do not fail in any general way in measuring the economic value of plants and animals. Market prices, in general, correctly represent the marginal or exchange value of species. If society legislates against extinction, this must be understood as an exercise in Kantian decision making in view of the moral value of species, not as an attempt to correct a market failure or to promote social welfare or utility. 相似文献
387.
山地灾害对新重庆社会经济环境的重要影响 总被引:8,自引:0,他引:8
基于新重庆的山地环境与社会经济环境特征,结合该区山地灾害大量的综合调研资料,对境内主要山地灾害类型及其现状进行归纳;对其严重的社会经济影响进行了较为深入的分析;在此基础上得出了几点有益的认识。 相似文献
388.
389.
Scientists assert that integrated research is a foundation of Sustainable Development. However, they often presume that differences between the bio-physical and social sciences are hurdles in the way of integration. We show that need not be the case. The problem lies in the way environmental research is organised. The essay goes on to discuss how the problem is being resolved, and the implications for ‘environmental science’. 相似文献
390.
HSE项目管理体系中环境保护专业的作用 总被引:1,自引:0,他引:1
饶未欣 《石油化工环境保护》2003,26(3):1-5
在对比国内建设项目环保管理体系和HSE环保管理体系的基础上,总结了PMC项目环保管理工作的经验,对HSE项目管理运作模式中环保专业的职能和作用进行了一定程度的探讨。 相似文献