全文获取类型
收费全文 | 417篇 |
免费 | 11篇 |
国内免费 | 10篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 11篇 |
环保管理 | 62篇 |
综合类 | 75篇 |
基础理论 | 113篇 |
环境理论 | 1篇 |
污染及防治 | 98篇 |
评价与监测 | 40篇 |
社会与环境 | 9篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 12篇 |
2014年 | 23篇 |
2013年 | 39篇 |
2012年 | 19篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 23篇 |
2008年 | 28篇 |
2007年 | 20篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1961年 | 2篇 |
1960年 | 1篇 |
1954年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有438条查询结果,搜索用时 203 毫秒
31.
John Young Luke Iwanowicz Adam Sperry Vicki Blazer 《Environmental monitoring and assessment》2014,186(9):5531-5545
Endocrine-disrupting compounds (EDCs) are becoming of increasing concern in waterways of the USA and worldwide. What remains poorly understood, however, is how prevalent these emerging contaminants are in the environment and what methods are best able to determine landscape sources of EDCs. We describe the development of a spatially structured sampling design and a reconnaissance survey of estrogenic activity along gradients of land use within sub-watersheds. We present this example as a useful approach for state and federal agencies with an interest in identifying locations potentially impacted by EDCs that warrant more intensive, focused research. Our study confirms the importance of agricultural activities on levels of a measured estrogenic equivalent (E2Eq) and also highlights the importance of other potential sources of E2Eq in areas where intensive agriculture is not the dominant land use. Through application of readily available geographic information system (GIS) data, coupled with spatial statistical analysis, we demonstrate the correlation of specific land use types to levels of estrogenic activity across a large area in a consistent and unbiased manner. 相似文献
32.
Kapheim KM Bernal SP Smith AR Nonacs P Wcislo WT 《Behavioral ecology and sociobiology》2011,65(6):1179-1190
Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish
from other environmental factors. This is an important distinction within the context of social evolution, because if variation
in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as
those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which
might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary
nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive
helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores
provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content
varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content,
for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio
ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in
maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social
plasticity observed in M. genalis. 相似文献
33.
Adam Pawełczyk 《Environmental monitoring and assessment》2013,185(1):497-508
This paper presents the results of analyses of water samples taken from water intakes supplying one of the districts located near the city of Wroc?aw. Surprisingly high concentrations of polychlorinated biphenyls and chloroorganic pesticides, classified as persistent organic pollutants (POPs), were detected in the monitored sites. Basing on the analytical and toxicological data, the individual health risks related to carcinogenic effects (excess cancer risk over a lifetime) in humans were assessed, resulting from direct ingestion of community water. Also noncarcinogenic effects resulting from exposure to the examined POPs were determined. The conservative approach to risk assessment, taking into account a safety margin for data incompleteness, was adopted. The carcinogenic risk was found to slightly exceed the unconditionally acceptable risk of 10?6 in the case of polychlorinated biphenyls and hexachlorocyclohexane, for all the inhabitant populations. The determined values of noncarcinogenic effects expressed by hazard quotient and hazard index indicate that the water pollutants and their concentrations do not cause an increase in noncarcinogenic incidences in the inhabitants using the monitored water sources. 相似文献
34.
This paper provides a case study of recent work undertaken in Melbourne relating to a mall re-development project. It begins by discussing the nature of shopping centres as sites of consumption and non-commercial social activities. It then describes planning and development strategies that provide innovative and socially progressive interventions in regard to the social, physical and regulatory environments of public malls. The importance of seeing such sites as 'community spaces', of promoting activities on the basis of social inclusion, of creating a safe, convivial atmosphere, and of establishing low-key friendly sorts of mall management, are highlighted. 相似文献
35.
Land Conversion for Suburban Housing: A Study of Urbanization Around Warsaw and Olsztyn,Poland 总被引:9,自引:0,他引:9
In Poland of the 1990s, urban demand for housing land around city agglomerations increased rapidly. The decreasing profitability of agricultural production also caused farmers to become interested in the sale of agricultural land for nonagricultural purposes, and new land legislation granted them the right to sell their land. Polish counties simultaneously received self-governing status, which allowed them to define the priorities for local development. Counties received additional responsibility for land management and quickly demonstrated strong support for land conversion, which was perceived as a factor of local development. This paper argues that decentralization and the extension of private control over land have led to a loss of rural landscapes in Poland because farmers, county governments, and rural society in general gained from the conversion of agricultural to housing land. Rapid urbanization has significantly reduced the availability of open space around cities and threatened valuable landscapes, for it has occurred in the absence of environmental safeguards. This paper reports findings from research in two counties, located in regions with diverse economic growth rates. Decentralization is particularly problematic if tax regulations and intergovernmental fiscal relations reward local authorities for urbanization but not environmental protection.
Note: This version was published online in June 2005 with the cover date of August 2004. 相似文献
36.
37.
Adam J. Wolfberg 《黑龙江环境通报》2018,38(3):219-221
Authors of policy statements from the American College of Obstetricians and Gynecologists and from the Society for Maternal-Fetal Medicine do not acknowledge the potential for their clinical income to influence their opinions, or the positions of the societies they represent. These policy statements were published in Obstetrics and Gynecology and the American Journal of Obstetrics and Gynecology, again, without acknowledgment of the potential for conflict of interest. The case of noninvasive prenatal testing, which has threatened the role of maternal-fetal medicine in the practice of prenatal screening and diagnosis, and has significantly reduced the demand for invasive prenatal diagnosis, illustrates the importance of identifying this potential conflict. 相似文献
38.
Karen L. Stals Matthew Wakeling Júlia Baptista Richard Caswell Andrew Parrish Julia Rankin Carolyn Tysoe Garan Jones Adam C. Gunning Hana Lango Allen Lisa Bradley Angela F. Brady Helena Carley Jenny Carmichael Bruce Castle Deirdre Cilliers Helen Cox Charu Deshpande Abhijit Dixit Jacqueline Eason Frances Elmslie Andrew E. Fry Alan Fryer Muriel Holder Tessa Homfray Emma Kivuva Victoria McKay Ruth Newbury-Ecob Michael Parker Ravi Savarirayan Claire Searle Nora Shannon Deborah Shears Sarah Smithson Ellen Thomas Peter D. Turnpenny Vinod Varghese Pradeep Vasudevan Emma Wakeling Emma L. Baple Sian Ellard 《黑龙江环境通报》2018,38(1):33-43
针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。 相似文献
39.
Animal lifespans range from a few days to many decades, and this life history diversity is especially pronounced in ants.
Queens can live for decades. Males, in contrast, are often assumed to act as ephemeral sperm delivery vessels that die after
a brief mating flight—a view developed from studies of lekking species in temperate habitats. In a tropical ant assemblage,
we found that males can live days to months outside the nest, a trait hypothesized to be associated with female calling, another
common mating system. We combined feeding experiments with respirometry to show that lifespan can be enhanced over 3 months
by feeding outside the nest. In one focal female calling species, Ectatomma ruidum, feeding enhanced male lifespan, but not sperm content. Extended lifespans outside the nest suggest stronger than expected
selection on premating traits of male ants, although the ways these traits shape male mating success remain poorly understood. 相似文献
40.