全文获取类型
收费全文 | 404篇 |
免费 | 9篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 23篇 |
废物处理 | 11篇 |
环保管理 | 60篇 |
综合类 | 62篇 |
基础理论 | 112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 | 3篇 |
出版年
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 14篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 21篇 |
2013年 | 39篇 |
2012年 | 18篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 27篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 9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419条查询结果,搜索用时 15 毫秒
371.
372.
Wim Bonckaert Adam Tofilski Fabio S. Nascimento Johan Billen Francis L. W. Ratnieks Tom Wenseleers 《Behavioral ecology and sociobiology》2011,65(4):633-640
In insect societies, workers often try to challenge the reproductive monopoly of the queen by laying their own eggs. Successful
worker reproduction, however, is frequently prevented by queen policing or worker policing, whereby either the mother queen
or non-reproductive workers selectively kill worker-laid eggs. Recently, a third mechanism—“selfish” worker policing—has also
been described in which the workers selectively police worker-laid eggs but also lay eggs themselves. Here, we present results
from the monogynous wasp Dolichovespula norwegica, which show that all three kinds of policing—queen policing, worker policing and “selfish” worker policing—co-occur. The
net effect of these three kinds of policing collectively favoured the queen’s reproduction, as within 1 day 44% of the worker-laid
eggs versus only 8% of the queen-laid eggs were eaten. Of the worker-laid eggs that were killed by workers, approximately
two thirds were eaten by the reproductive workers even though these made up only a small proportion, 8%, of the work force.
This means that policing workers obtained both direct fitness benefits as well as indirect (inclusive) fitness. In addition,
we show that worker policing was carried out by a limited, specialised set of workers that was estimated to constitute approximately
one quarter of the whole colony and of which 66% were non-reproductive. 相似文献
373.
Yang RJ Xia AG Michelangeli DV Plummer DA Neary L Kaminski JW McConnell JC 《Journal of environmental monitoring : JEM》2003,5(1):40-46
The simulated concentrations from a numerical 3-dimensional regional air quality model (MC2AQ) are compared to those of ground-based observations in north-eastern Canada and the United States. The model has oxidant chemistry for both inorganic and organic species and deposition routines driven online by a mesoscale compressible community meteorological model (MC2). A standard emission inventory of anthropogenic, natural and biogenic sources for the year 1990 for 21 atmospheric trace species was used in the simulation. The model was run for July 1999, because of the occurrence of a high ozone episode and the availability of the monitoring data for surface O3, SO2, NO, NO2 and NOx. The comparisons during the episode show that the model performs quite well for predicting concentrations and diurnal variations of the surface ozone. The predictions for other gaseous species show some discrepancies with observations, but they are consistent with the results from other models evaluated in the literature. The uncertainties in the emission inventory for these species might be the main causes of the discrepancies. Further studies are needed to improve the predictability of SO and NOx, especially as the model is developed to include particulate matter formation as a result of these gaseous precursors. 相似文献
374.
Mean Annual Temperature and Total Annual Precipitation Trends at Canadian Biosphere Reserves 总被引:1,自引:0,他引:1
This article examines instrumental climate records from a varietyof stations associated with the following Biosphere Reserves across Canada: (i) Waterton Lakes, (ii) Riding Mountain, (iii) Niagara Escarpment, (iv) Long Point, and (v) Kejimkujik (Candidate Biosphere Reserve). Annual series are generated fromdaily temperature and precipitation values. In addition, homogeneous data are used from other stations and regional records to supplement the records from the local biosphere stations. Long term trends are identified over the period of the instrumental record. In general, data from the interval 1900 to 1998 show cooler temperatures in the 1920's, warmingfrom the early 1940's into the early 1950's, cooling into the1970's, and subsequent warming. At many stations, 1998 is the warmest in the instrumental record. Comparisons with the regional data sets show good agreements between the temperatureseries. The 20th century warming is approximately 1.0 °C in the Riding Mountain area and 0.6 °Cin the Long Point, Niagara Escarpment, and Waterton Lakes areas.There has been slight cooling in the Kejimkujik area over the past half century. Precipitation data show increasing trends inthe Kejimkujik, Long Point, Niagara Escarpment, and Waterton Lakes areas with no long term trend in the Riding Mountain area. This work is part of the Canadian Biosphere Reserves Association (CBRA) Climate Change Initiative (CCI), designed to present climate change information to Biosphere Reserve communities to allow local organizations to understand climate change and adapt to potential impacts. 相似文献
375.
376.
R. Williamson M. E. D. Allison T. J. Bentley S. M. C. Lim E. Watson J. Chapple S. Adam M. Boulton 《黑龙江环境通报》1989,9(10):727-734
Inexpensive and accurate carrier testing for cystic fibrosis (CF) will be possible in the near future. There are no existing studies on the attitudes of English persons in the community to carrier testing for CF or any other recessive disorder. We have conducted a trial study of 166 persons at two schools, two doctors' surgeries, and a family planning clinic. Only a minority had clear pre-existing knowledge of cystic fibrosis and its genetic nature. However, over 80 per cent of those questioned expressed interest in knowing their carrier status. Although it is well known that uptake can only be assessed when a service is in place, and while further studies are required to confirm that testing will be of interest to couples of reproductive age with no previous knowledge of CF, the data strongly suggest that there will be interest in communitywide testing for CF carrier status when such a test becomes available in the United Kingdom. 相似文献
377.
Adam S Davis Douglas A Landis Victoria Nuzzo Bernd Blossey Esther Gerber Hariet L Hinz 《Ecological applications》2006,16(6):2399-2410
Nonindigenous invasive plants pose a major threat to natural communities worldwide. Biological control of weeds via selected introduction of their natural enemies can affect control over large spatial areas but also risk nontarget effects. To maximize effectiveness while minimizing risk, weed biocontrol programs should introduce the minimum number of host-specific natural enemies necessary to control an invasive nonindigenous plant. We used elasticity analysis of a matrix model to help inform biocontrol agent selection for garlic mustard (Alliaria petiolata (M. Bieb.) Cavara and Grande). The Eurasian biennial A. petiolata is considered one of the most problematic invaders of temperate forests in North America. Four weevil species in the genus Ceutorhynchus (Coleoptera: Curculionidae) are currently considered potential biocontrol agents. These species attack rosettes (C. scrobicollis), stems (C. roberti, C. alliariae), and seeds (C. constrictus) of A. petiolata. Elasticity analyses using A. petiolata demographic parameters from North America indicated that changes in the rosette-to-flowering-plant transition and changes in fecundity consistently had the greatest impact on population growth rate. These results suggest that attack by the rosette-feeder C. scrobicollis, which reduces overwintering survival, and seed or stem feeders that reduce seed output should be particularly effective. Model outcomes differed greatly as A. petiolata demographic parameters were varied within ranges observed in North America, indicating that successful control of A. petiolata populations may occur under some, but not all, conditions. Using these a priori analyses we predict: (1) rosette mortality and reduction of seed output will be the most important factors determining A. petiolata demography; (2) the root-crown feeder C. scrobicollis will have the most significant impact on A. petiolata demography; (3) releases of single control agents are unlikely to control A. petiolata across its full range of demographic variability; (4) combinations of agents that simultaneously reduce rosette survival and seed production will be required to suppress the most vigorous A. petiolata populations. These predictions can be tested using established long-term monitoring sites coupled with a designed release program. If demographic models can successfully predict biocontrol agent impact on invasive plant populations, a continued dialogue and collaboration between empirical and theoretical approaches may be the key to the development of successful biocontrol tactics for plant invaders in the future. 相似文献
378.
Kevin C. Weng Andre M. Boustany Peter Pyle Scot D. Anderson Adam Brown Barbara A. Block 《Marine Biology》2007,152(4):877-894
Satellite telemetry studies of 20 adult and sub-adult white sharks (360–530 cm estimated total length (TL)) in the eastern
North Pacific during 1999–2005 revealed long distance seasonal migrations from the coast of California to an offshore focal
area 2,500 km west of the Baja Peninsula, as well as the Hawaii Islands. Three tags were recovered allowing detailed behavioral
analyses, including one shark’s migration cycle from the coast to the offshore focal area and back. While near pinniped rookeries
in autumn and winter, sharks avoided the surface and used water to 50 m depth, consistent with a silhouette-based hunting
strategy. Offshore migrations were initiated during November–March and followed periods of decreasing pinniped abundance.
Migrations were highly directed, taking 23 ± 5 days to reach the offshore focal area along similar paths among sharks and
years, defining a migration corridor. Sharks exhibited a broad depth distribution (0–644 m) in the offshore focal area, and
remained there for up to 167 days during spring and summer, though primary productivity and fishery data suggest that forage
resources are scarcer there than in other regions of the eastern North Pacific. Archival data from one shark revealed intensive
oscillatory movements while in the offshore focal area, a behavior that may be related to foraging or mating. Sharks traveling
to Hawaii remained near the islands up to 122 days, potentially feeding on pelagic fishes and marine mammals that concentrate
around the islands.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
379.
380.