全文获取类型
收费全文 | 617篇 |
免费 | 19篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 33篇 |
环保管理 | 98篇 |
综合类 | 72篇 |
基础理论 | 189篇 |
污染及防治 | 161篇 |
评价与监测 | 46篇 |
社会与环境 | 24篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 26篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 14篇 |
2013年 | 66篇 |
2012年 | 15篇 |
2011年 | 24篇 |
2010年 | 18篇 |
2009年 | 25篇 |
2008年 | 36篇 |
2007年 | 36篇 |
2006年 | 18篇 |
2005年 | 23篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 19篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有641条查询结果,搜索用时 343 毫秒
421.
D W Fitzpatrick K E Boyd L M Wilson J R Wilson 《Journal of environmental science and health. Part. B》1988,23(2):159-170
Male Sprague-Dawley rats (180 g) and 28-day-old Single Comb White Leghorn Cockerels (300 g) were orally dosed with deoxynivalenol (DON) at 2.5 mg kg-1 body weight. In the first experiment, whole brains were collected at 2, 6, 12, 24 and 48 hours after the toxin treatment and analyzed for brain biogenic monoamines by high-performance liquid chromatography with electrochemical detection. Although several interesting trends were observed, DON did not influence whole brain concentrations of monoamine neurotransmitters or their metabolites in either species, at any time. In a second experiment, brains were collected 24 hours postdosing, dissected into 5 brain regions (pons and medulla oblongata, cerebellum, hypothalamus, hippocampus and cerebral cortex), and analyzed. DON treatment resulted in significantly elevated concentrations of serotonin (HT) and 5-hydroxyindole-3-acetic acid (HIAA) in all brain regions of the rat. However, this was not seen in poultry, where DON treatment resulted in a decrease in norepinephrine (NE) in the hypothalamus and hippocampus, and a decrease in dopamine (DA) in the pons and medulla oblongata region. These results suggest that DON influences brain biogenic amine metabolism, and that there may be intraspecies differences in the central effects of this mycotoxin. 相似文献
422.
423.
This study estimates the social benefits of wetland conservation in the Credit River watershed, located in an urban/peri urban area in Southern Ontario, Canada. A stated preference approach was employed to value wetland conservation programs which ranged from retaining the existing wetlands to restoring various levels of acres of wetlands over the 2009–2020 period. A total of 1,407 households completed an internet-based survey which presented trade-offs in binary choice scenarios framed as referenda. Responses were analyzed using various models, one of which was a latent class analysis which segmented respondents into three classes. This econometric approach uncovered significant preference heterogeneity for wetland conservation. Assignment of respondents to the classes suggested that about one-third of the sample was willing to pay small amounts to retain the existing wetlands. An additional third was willing to pay several hundred dollars a year for retention and small positive amounts for additional restoration. The final third were apparently willing to pay considerable sums for retention, but lesser amounts for additional restoration. However, further analysis revealed that respondents in this third class largely constituted yea-sayers. These results suggest caution in interpreting associated economic valuation estimates and highlight the importance of attempting to understand hypothetical bias in wetland and other such valuation studies. 相似文献
424.
Research has been conducted into the application of forced acoustics for enhancing the performance of a pyrolyzed waste afterburner configured as a dump combustor. Subscale studies showed that acoustic forcing of an air jet entering a dump chamber could trigger the formation of coherent vortices generated by entrainment of ambient gases. Subsequent studies showed that combustible gases could be introduced into the coherent vortices, and with additional modulation this configuration would lead to an enhanced combustion rate with low emissions of pollutants. The acoustically forced burner concept was scaled up to practical levels and tested as an afterburner on a commercial waste incinerator operating in pyrolysis mode. Results show that the afterburner can promote both compactness, due to the rapid combustion rate, and low pollutant emissions resulting from enhanced mixing prior to combustion. 相似文献
425.
Migration of pollutants in groundwater. II. adsorbable pollutants and numerical dispersion reduction
Kenneth N. Carter Jr. Melio Saenz David J. Wilson Philip W. Rosten Jr. 《Environmental monitoring and assessment》1984,4(2):171-202
We discuss here the partial differential equations governing the migration of a decomposing pollutant adsorbing according to a Langmuir isotherm and undergoing 2-dimensional flow in a saturated aquifer. The equation governing the mass transfer of the pollutant to the surfaces within the aquifer are solved in closed form, permitting the use of larger values of the time increment t in the numerical integration of the dispersion-advection equation governing the behavior of the dissolved pollutant. In this numerical integration transverse numerical dispersion is eliminated by using conformal coordinates (velocity potential and stream function), and longitudinal numerical dispersion is very substantially reduced by use of an asymmetrical 4-point formula to represent the advection term. Some representative results are given as contour maps. The mass transfer rate coefficient is estimated as the least positive eigenvalue of a diffusion problem. 相似文献
426.
Hall AJ Duck CD Law RJ Allchin CR Wilson S Eybator T 《Environmental pollution (Barking, Essex : 1987)》1999,106(2):203-212
Organochlorine contaminants (pesticides and individual polychlorinated biphenyl congeners, PCBs) were measured in Caspian (Phoca caspica) seal blubber and compared with concentrations in Harbour (Phoca vitulina) seal blubber. Concentrations of total dichlorodiphenyltrichloroethane (DDT) and its metabolites were significantly higher in Caspian seal than Harbour seal samples, whereas PCB congeners were significantly higher in Harbour than Caspian seals. Our finding suggests that Caspian seals are exposed to high levels of DDT pesticides. In contrast, PCBs are circulating in this population at much lower levels than in marine mammals from the North Sea. 相似文献
427.
W. H. Wilson Jr. 《Marine Biology》1983,76(3):297-300
Individual Axiothella rubrocincta Johnson on the Californian coast live in U-shaped tubes, feed on the surface of the sediment, attain densities of 100 m-2, attain lengths of 140 mm, have maximum oocyte diameters of 220 μm and produce demersal larvae. Individuals from Washington populations live in vertical tubes, feed 10–15 cm below the sediment surface, reach densities of 5000 m-2, attain lengths of 60 mm, have maximum oocyte diameters of 385 μm and brood their young in their tubes to at least the 7-setiger stage. Individuals from California have a scalloped posterior margin of the cephalic plate, while individuals from Washington have entire margins. There are no other consistent morphological differences between populations. The population from Eagle Cove, Washington has individuals similar in size and oocyte diameter to individuals from California, but which maintain vertical tubes. A. rubrocincta represents a sibling species complex. 相似文献
428.
Large numbers of the lophogastrid mysid Gnathophausia longispina were discovered in 1984 over Southeast Hancock Seamount on the northern Hawaiian Ridge. Additional specimens were collected from the same area during subsequent surveys in 1985, 1987, and 1988 to obtain new information on the life history of this species. Estimates of growth suggest that G. longispina reaches sexual maturity by its second year. Young are brooded by the female for nearly a year and released in late winter-early spring. It is doubtful if G. longispina live longer than 2 yr or produce more than one brood. Most G. longispina are found within 100m above the seamount summit. The modal progression of size classes over time indicates that this species is dependent on local processes rather than recruitment from other areas to maintain its populations at the seamount. 相似文献
429.
Harris ML Elliott JE Butler RW Wilson LK 《Environmental pollution (Barking, Essex : 1987)》2003,121(2):207-227
Over the period 1977-2000, eggs of Pacific great blue heron (Ardea herodias fannini) were collected from 23 colonies along the southern coast of British Columbia, Canada, and analyzed for persistent organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs). Concentrations of OC pesticides in eggs declined sharply in the late 1970s, after which there were minimal changes. The sums of PCB congeners were not reduced appreciably during the 1980s and 1990s, but Aroclor 1260 concentrations suggested a sharp decline in PCB contamination of eggs in the late 1970s, similar to that shown for OC pesticides. Eggs collected along or near the Fraser River delta showed higher levels of most pesticides compared to other monitored colonies. Although the delta lands support a long-standing agricultural economy, the primary factors influencing OC levels in the delta colonies were thought to be driven by estuarine processes. We suggest two possible influencing factors were: 1) a greater rate of bioaccumulation in the estuary due to the deposition of particulates collected over a vast area encompassed by the Fraser River watershed; or 2) a higher rate of biomagnification in the estuary due to species differences at lower trophic levels of the heron food chain. Eggs from urban colonies contained higher levels of PCBs. The congener pattern was not clearly different from that observed in less contaminated eggs from rural and pulp mill-influenced colonies, except that colonies in Vancouver had greater proportions of PCB-66, suggesting a local source of Aroclor 1242. Productivity in the coastal heron colonies was highly variable over the period of study, with 71% of recorded colony-wide reproductive failures occurring in colonies near pulp mills. However, the predominant factors influencing reproductive success were probably disturbance by humans and bald eagles, combined with loss and degradation of nesting habitat, and not sublethal toxicity. 相似文献
430.
Field-boundary structure, its use by territorial Whitethroats, and its management by farmers were investigated in southern Wiltshire using a combination of fieldwork and a questionnaire survey. Whitethroats favour wide herbaceous field boundary strips and low hedges. Long-term cultural and short-term economic interests combine to influence farmers' management decisions. Only farmers with game and conservation interests claimed to adopt field-boundary management that would benefit Whitethroats, but across all farms, intended and actual herbaceous strips were too narrow, and their management too imprecise, for Whitethroats and other wildlife. Agricultural advisors and magazines were the main influences on farmers' management decisions. Improving habitat for Whitethroats could have both agronomic and wider conservation benefits, and the provision of information that accommodates farmers' cultural and economic incentives could benefit both farmers and wildlife. 相似文献