全文获取类型
收费全文 | 245篇 |
免费 | 0篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 5篇 |
环保管理 | 14篇 |
综合类 | 97篇 |
基础理论 | 44篇 |
污染及防治 | 67篇 |
评价与监测 | 10篇 |
社会与环境 | 11篇 |
出版年
2020年 | 5篇 |
2018年 | 8篇 |
2016年 | 9篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 9篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1980年 | 2篇 |
1976年 | 2篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 3篇 |
1964年 | 3篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 5篇 |
1960年 | 2篇 |
1958年 | 3篇 |
1956年 | 2篇 |
1955年 | 3篇 |
1954年 | 5篇 |
1952年 | 2篇 |
1951年 | 2篇 |
1934年 | 3篇 |
1916年 | 3篇 |
排序方式: 共有249条查询结果,搜索用时 15 毫秒
91.
Wolfgang Priester (1924–2005) was one of Germany’s most versatile and quixotic astrophysicists, reinventing himself successively
as a radio astronomer, space physicist and cosmologist, and making a lasting impact on each field. We focus in this personal
account on his contributions to cosmology, where he will be most remembered for his association with quasars, his promotion
of the idea of a nonsingular “big bounce” at the beginning of the current expansionary phase, and his recognition of the importance
of dark energy (Einstein’s cosmological constant Λ) well before this became the standard paradigm in cosmology.
In memoriam Wolfgang Priester, 22 April 1924 – 9 July 2005 相似文献
92.
Ingrid Christine Koch Coleen Vogel Zarina Patel 《Mitigation and Adaptation Strategies for Global Change》2007,12(8):1323-1339
Climate change is a multi-dimensional issue and in terms of adaptation numerous state and non-state actors are involved from
global to national and local scales. The aim of this paper is first to analyse specific institutional networks involved in
climate change predominantly at the national level in South Africa and second to determine how different stakeholders perceive
their role vis-a-vis climate change adaptation. Within the South African context there is a gap in understanding and evaluating
how institutional networks operate and thus the findings of this work may help inform and strengthen such relationships in
the future. Results showed that few institutions fully understand the implications of adaptation and their roles and responsibilities
have not yet been properly defined. Constraints relating to capacity, lack of awareness and poor information flow need to
be addressed. Climate change is perceived as an important issue although problems such as poverty reduction and job creation
remain national priorities. Most importantly this research has demonstrated how adaptation challenges the hierarchical manner
in which government works and a more collaborative approach to climate change adaptation is needed. Adaptation needs to be
mainstreamed and institutional networks need to be strengthened in order for adaptation mechanisms to be effectively implemented.
相似文献
Ingrid Christine KochEmail: |
93.
Benjamin J. Koch Catherine M. Febria Muriel Gevrey Lisa A. Wainger Margaret A. Palmer 《Journal of the American Water Resources Association》2014,50(6):1594-1607
A comprehensive synthesis of data from empirically based published studies and a widely used stormwater best management practice (BMP) database were used to assess the variability in nitrogen (N) removal performance of urban stormwater ponds, wetlands, and swales and to identify factors that may explain this variability. While the data suggest that BMPs were generally effective on average, removal efficiencies of ammonium (NH4), nitrate (NO3), and total nitrogen (TN) were highly variable ranging from negative (i.e., BMPs acting as sources of N) to 100%. For example, removal of NO3 varied from (median ±1 SD) ?15 ± 49% for dry ponds, 32 ± 120% for wet ponds, 58 ± 210% for wetlands, and 37 ± 29% for swales. Across the same BMP types, TN removal was 27 ± 24%, 40 ± 31%, 61 ± 30%, and 50 ± 29%. NH4 removal was 9 ± 36%, 29 ± 72%, 31 ± 24%, and 45 ± 34%. BMP size, age, and location explained some of the variability. For example, small and shallow ponds and wetlands were more effective than larger, deeper ones in removing N. Despite well‐known intra‐annual variation in N fluxes, most measurements have been made over short time periods using concentrations, not flow‐weighted N fluxes. Urban N export is increasing in some areas as large storms become more frequent. Thus, accounting for the full range of BMP performance under such conditions is crucial. A select number of long‐term flux‐based BMP studies that rigorously measure rainfall, hydrology, and site conditions could improve BMP implementation. 相似文献
94.
A model predictive of the potential mutagenicity of organic compounds was devised by relating mutagenicity data obtained in the Ames reversion test to molecular structure parameters describing their hydrophobic, topological, steric and electronic properties. These included second order valence molecular connectivity index, parachor, molar refraction and polarizability of electrons. A classification rule was calculated, by means of discriminant analysis, using a training set of 117 compounds of various chemical classes. There was agreement between experimental data and theoretical expectations for the majority of compounds (70.9%), with homogeneous figures among the different chemical classes under scrutiny. An exception was represented by halogenated aliphatics with up to 3 C atoms, the mutagenicity of which was poorly predicted by the structural analysis model. 相似文献
95.
Tim Ruploh Hans-Joachim Bischof Nikolaus von Engelhardt 《Behavioral ecology and sociobiology》2014,68(4):537-549
Group-living animals rely on social skills which ensure beneficial interaction and prevent harmful ones with conspecifics. In a previous experiment, we demonstrated that male zebra finches reared in groups during adolescence show consistently less courtship and aggressive behaviour as adults than pair-reared males. Here we tested whether such differences affect how they group with conspecifics, as an indicator of their social integration. Zebra finches were kept in pairs (male–female or male–male) or mixed-sex groups (three males and three females) during adolescence and were introduced to an established group of unknown conspecifics during adulthood. Male courtship and aggressive behaviour were quantified directly after introduction to the group and 48 h later. At the same time, male position in relation to other birds and the number of birds in proximity were recorded. Males that grew up in a small mixed-sex group during adolescence spent more time within groups, were observed in bigger groups and lost less weight than males raised in pairs, indicating that an enriched social environment during early development may facilitate social integration. However, we observed no differences in courtship and aggressive behaviour that could predict the differences in grouping behaviour of pair- and group-reared males. We discuss alternative explanations for the difference in grouping and how to test these in future research. 相似文献
96.
Stefan Schrader Jürgen Bender Hans-Joachim Weigel 《Environmental pollution (Barking, Essex : 1987)》2009,157(12):3357-3362
A 2-year open-top chamber experiment with field-grown winter wheat (Triticum aestivum L. cv. Astron) was conducted to examine the effects of ozone on plant growth and selected groups of soil mesofauna in the rhizosphere. From May through June in each year, plants were exposed to two levels of O3: non-filtered (NF) ambient air or NF+ 40 ppb O3 (NF+). During O3 exposure, soil sampling was performed at two dates according to different plant growth stages. O3 exposure reduced above- and below-ground plant biomass in the first year, but had little effect in the second year. The individual density of enchytraeids, collembolans and soil mites decreased significantly in the rhizosphere of plants exposed to NF+ in both years. Differences were highest around anthesis, i.e. when plants are physiologically most active. The results suggest that elevated O3 concentrations may influence the dynamic of decomposition processes and the turnover of nutrients. 相似文献
97.
98.
99.
100.