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161.
162.
Ryan PG 《Environmental pollution (Barking, Essex : 1987)》1987,46(2):119-125
Multivariate analyses were used to assess the independent influences of body size, ingested plastic load and parasite load on bird mass and on an index of fat reserves in great shearwaters and blue petrels. PLastic load was negatively correlated with body condition in the sample of blue petrels collected after the post-nuptial moult, but differences in reproductive status may account for this negative correlation. Ingested plastic loads had no apparent effect on blue petrels and great shearwaters collected at the same stage of reproduction, despite high plastic loads in some individuals. The limitations of using correlations to demonstrate the effects of plastic ingestion are discussed. 相似文献
163.
In situ soil treatments to reduce the phyto- and bioavailability of lead, zinc, and cadmium 总被引:10,自引:0,他引:10
A study was established near a former Zn and Pb smelter to test the ability of soil amendments to reduce the availability of Pb, Zn, and Cd in situ. Soil collected from the field was amended in the lab with P added as 1% P-H3PO4, biosolids compost added at 10% (referred to hereafter as "compost"), and a high-Fe by-product (referred to hereafter as "Fe") + P-triple superphosphate (TSP) (2.5% Fe + 1% P-TSP) and incubated under laboratory conditions at a constant soil pH. Changes in Pb bioavailability were measured with an in vitro test and a feeding study with weanling rats. Field-amended and incubated soils using these plus additional treatments were evaluated using the in vitro extraction and tall fescue (Festuca arundinacea Schreb. cv. Kentucky-31) metal concentration. Reductions were observed across all parameters but were not consistent. In the feeding study, the 1% P-H3PO4 and compost treatments resulted in a decrease of 26% in rat tissue Pb concentration compared with the control soil. The 2.5% Fe + 1% P-TSP showed a 39% decrease. The 1% P-H3PO4 treatment caused the greatest reduction in in vitro extractable Pb from field samples (pH 2.2) with a measured reduction of 66%, while the compost treatment had a 39% reduction and the 2.5% Fe + 1% P-TSP treatment a 50% reduction. The in vitro extraction (pH 1.5) run on field samples showed no reduction in the compost or Fe treatments. The 1% P-H3PO4 treatment was the most effective at reducing plant Pb, Zn, and Cd. 相似文献
164.
The network described in this paper has been set up to provide detailed time-series data on concentrations of 222Rn in air at various locations within the Alligator Rivers Region, over a time frame of several years. These data will be important in assessing the effects of uranium mining operations on radon levels in the region, both in providing baseline and monitoring data and in calibrating and verifying predictive models. At present, three stations are operating in the region with a fourth being commissioned. Each station logs half hourly average radon concentrations and relevant meteorological data (wind speed, direction and variability, air pressure and temperature, relative humidity, soil temperature, rain and sunshine rates). It is intended to operate the four stations at selected locations for one- or two-year intervals, at the end of which three will be moved to new locations (one station at Mudginberri will be kept as a constant control station). Sites for which extensive datasets are currently available include: Jabiru Town, Jabiru East, Djarr Djarr, East Alligator Ranger Station and Nabarlek minesite. Illustrative data from these sites are presented. 相似文献
165.
Declines in salmon stocks and general watershed health in Washington State, USA, have led to an increase in stream restoration
and enhancement projects initiated throughout the state. The increasing number of projects has also raised questions regarding
the monitoring of these efforts. Project managers receiving hydraulic project approvals (HPAs) were surveyed to determine
whether monitoring was taking place on their projects. About half the project managers surveyed reported the collection of
baseline data and the use of biological, physical, chemical, or other water quality measures for their projects. Of those
who reported collection of monitoring data, only 18% indicated that monitoring was required. Respondents were also asked to
rank the importance of various project goals on a Likert scale. Project managers with projects focusing on “engineering” goals
(e.g., roadbed stabilization) were less likely than other project managers to collect baseline monitoring data. Project managers
with projects focusing on “restoration/ecological” or “fisheries” goals were more likely than other project managers to collect
monitoring measures. Although monitoring appears to be taking place in slightly more than half of the projects surveyed, the
nature of the data collected varies widely across projects, and in most cases the monitoring effort is voluntary. This suggests
that project sponsors, funders, and managers must consider the issues involved in requiring appropriate monitoring, establishing
standardized monitoring guidelines, the time frames in which to monitor, providing other incentives for conducting monitoring,
and ensuring adequate funding for monitoring efforts. 相似文献
166.
While it is known that Antarctic sea ice biomass and productivity are highly variable over small spatial and temporal scales,
there have been very few measurements from eastern Antarctic. Here we attempt to quantify the biomass and productivity and
relate patterns of variability to sea ice latitude ice thickness and vertical distribution. Sea ice algal biomass in spring
in 2002, 2003 and 2004 was low, in the range 0.01–8.41 mg Chl a m−2, with a mean and standard deviation of 2.08 ± 1.74 mg Chl a m−2 (n = 199). An increased concentration of algae at the bottom of the ice was most pronounced in thicker ice. There was little
evidence to suggest that there was a gradient of biomass distribution with latitude. Maximum in situ production in 2002 was
approximately 2.6 mg C m−2 h−1 with assimilation numbers of 0.73 mg C (mg Chl a)−1 h−1. Assimilation numbers determined by the 14C incubations in 2002 varied between 0.031 and 0.457 mg C (mg Chl a)−1 h−1. Maximum fluorescence quantum yields of the incubated ice samples in 2002 were 0.470 ± 0.041 with E
k indices between 19 and 44 μmol photons m−2 s−1. These findings are consistent with the shade-adapted character of ice algal communities. In 2004 maximum in situ production
was 5.9 mg C m−2 h−1 with an assimilation number of 5.4 mg C (mg Chl a)−1 h−1. Sea ice biomass increased with ice thickness but showed no correlation with latitude or the time the ice was collected.
Forty-four percent of the biomass was located in bottom communities and these were more commonly found in thicker ice. Surface
communities were uncommon. 相似文献
167.
168.
169.
170.
Eliza Maher Hasselquist William Lidberg Ryan A. Sponseller Anneli Ågren Hjalmar Laudon 《Ambio》2018,47(5):546-556
Drainage of forested wetlands for increased timber production has profoundly altered the hydrology and water quality of their downstream waterways. Some ditches need network maintenance (DNM), but potential positive effects on tree productivity must be balanced against environmental impacts. Currently, no clear guidelines exist for DNM that strike this balance. Our study helps begin to prioritise DNM by: (1) quantifying ditches by soil type in the 68 km2 Krycklan Catchment Study in northern Sweden and (2) using upslope catchment area algorithms on new high-resolution digital elevation models to determine their likelihood to drain water. Ditches nearly doubled the size of the stream network (178–327 km) and 17% of ditches occurred on well-draining sedimentary soils, presumably making DNM unwarranted. Modelling results suggest that 25–50% of ditches may never support flow. With new laser scanning technology, simple mapping and modelling methods can locate ditches and model their function, facilitating efforts to balance DNM with environmental impacts. 相似文献