全文获取类型
收费全文 | 18007篇 |
免费 | 183篇 |
国内免费 | 163篇 |
专业分类
安全科学 | 512篇 |
废物处理 | 745篇 |
环保管理 | 2497篇 |
综合类 | 2438篇 |
基础理论 | 4805篇 |
环境理论 | 4篇 |
污染及防治 | 5229篇 |
评价与监测 | 1162篇 |
社会与环境 | 837篇 |
灾害及防治 | 124篇 |
出版年
2022年 | 127篇 |
2021年 | 156篇 |
2020年 | 99篇 |
2019年 | 141篇 |
2018年 | 245篇 |
2017年 | 243篇 |
2016年 | 402篇 |
2015年 | 339篇 |
2014年 | 506篇 |
2013年 | 1537篇 |
2012年 | 594篇 |
2011年 | 769篇 |
2010年 | 604篇 |
2009年 | 711篇 |
2008年 | 819篇 |
2007年 | 872篇 |
2006年 | 758篇 |
2005年 | 635篇 |
2004年 | 658篇 |
2003年 | 613篇 |
2002年 | 611篇 |
2001年 | 754篇 |
2000年 | 557篇 |
1999年 | 308篇 |
1998年 | 233篇 |
1997年 | 220篇 |
1996年 | 267篇 |
1995年 | 265篇 |
1994年 | 253篇 |
1993年 | 228篇 |
1992年 | 205篇 |
1991年 | 185篇 |
1990年 | 206篇 |
1989年 | 189篇 |
1988年 | 180篇 |
1987年 | 171篇 |
1986年 | 148篇 |
1985年 | 146篇 |
1984年 | 176篇 |
1983年 | 174篇 |
1982年 | 166篇 |
1981年 | 168篇 |
1980年 | 136篇 |
1979年 | 159篇 |
1978年 | 108篇 |
1977年 | 100篇 |
1976年 | 88篇 |
1975年 | 94篇 |
1973年 | 92篇 |
1972年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
711.
712.
Alberto Megías Antonio Maldonado Andrés Catena Leandro L. Di Stasi Jesús Serrano Antonio Cándido 《Safety Science》2011,49(10):1388-1393
In road safety literature the effects of emotional content and salience of advertising billboards have been scarcely investigated. The main aim of this work was to uncover how affect-laden roadside advertisements can affect attention – eye-movements – and subsequent risky decisions – braking – on the Honda Riding Trainer motorcycle simulator. Results indicated that the number of fixations and total fixation time elicited by the negative and positive emotional advertisements were larger than the neutral ones. At the same time, negative pictures got later gaze disengagement than positive and neutral ones. This attentional capture results in less eye fixation times on the road relevant region, where the important driving events happen. Finally, the negative emotional valence advertisements sped up braking on subsequent risky situations. Overall results demonstrated how advertisements with emotional content modulate attention allocation and driving decisions in risky situations and might be helpful for designing roadside advertisements regulations and risk prevention programs. 相似文献
713.
S.E. Gant M.R. Pursell C.J. Lea J. Fletcher W. Rattigan A.M. Thyer S. Connolly 《Process Safety and Environmental Protection》2011,89(6):472-481
The effect of carbon dioxide (CO2) concentration on the ignition behaviour of hydrocarbon and CO2 gas mixtures is examined in both jets and confined explosions. Results from explosion tests are presented using a 20 l explosion sphere and an 8 m long section of 1.04 m diameter pipeline. Experiments to assess the flame stability and ignition probability in free-jets are reported for a range of different release velocities. An empirically-based flammability factor model for free-jets is also presented and results are compared to ignition probability measurements previously reported in the literature and those resulting from the present tests.The results help to understand how CO2 changes the severity of fires and explosions resulting from hydrocarbon releases. They also demonstrate that it is possible to ignite gas mixtures when the mean concentration is outside the flammable range. This information may be useful for risk assessments of offshore platforms involved in carbon sequestration or enhanced oil recovery, or in assessing the hazards posed by poorly-inerted hydrocarbon processing plant. 相似文献
714.
Langston WJ O'Hara S Pope ND Davey M Shortridge E Imamura M Harino H Kim A Vane CH 《Environmental monitoring and assessment》2012,184(1):289-311
Biomonitoring of contaminants (metals, organotins, polyaromatic hydrocarbons (PAHs), PCBs) was undertaken in Milford Haven
Waterway (MHW) and a reference site in the Tywi Estuary (St Ishmael/Ferryside) during 2007–2008. Bioindicator species encompassed
various uptake routes—Fucus vesiculosus (dissolved contaminants); Littorina littorea (grazer); Mytilus edulis and Cerastoderma edule (suspension feeders); and Hediste (=Nereis) diversicolor (sediments). Differences in feeding and habitat preference have subtle implications for bioaccumulation trends though, with
few exceptions, contaminant burdens in MHW were higher than the Tywi reference site, reflecting inputs. Elevated metal concentrations
were observed at some MHW sites, whilst As and Se (molluscs and seaweed) were consistently at the higher end of the UK range.
However, for most metals, distributions in MH biota were not exceptional. Several metal-species combinations indicated increases
in bioavailability upstream, which may reflect the influence of geogenic/land-based sources—perhaps enhanced by lower salinity.
TBT levels in MH mussels were below OSPAR toxicity thresholds and in the Tywi were close to zero. Phenyltins were not accumulated
appreciably in M. edulis, whereas some H. diversicolor populations appear subjected to localized (historical) sources. PAHs in H. diversicolor were distributed evenly across most of MHW, although acenaphthene, fluoranthene, pyrene, benzo(a)anthracene and chrysene were highest at one site near the mouth; naphthalenes in H. diversicolor were enriched in the mid-upper Haven (a pattern seen in M. edulis for most PAHs). Whilst PAH (and PCB) concentrations in MH mussels were mostly above reference and OSPAR backgrounds, they
are unlikely to exceed ecotoxicological thresholds. Bivalve Condition indices (CI) were highest at the Tywi reference site
and at the seaward end of MH, decreasing upstream—giving rise to several significant (negative) relationships between CI and
body burdens. Despite the possible influence of salinity gradient as a complicating factor, multivariate analysis indicated
that a combination of contaminants could influence the pattern in condition (and the biomarkers metallothionein and TOSC).
Integrating bioaccumulation data with biological and biochemical endpoints is seen as a useful way to discriminate environmental
quality of moderately contaminated areas such as MHW and to prioritise cause and effect investigations. 相似文献
715.
Drinking water samples collected from rural areas of three districts of Haryana during pre-monsoon and post-monsoon periods
were analysed for the presence of organochlorine pesticide residues. The main source of drinking water in rural areas, i.e.
groundwater in Ambala and Gurgaon districts and surface water supply in Hisar district, was found to be contaminated with
isomers of HCH and endosulfan and metabolites of DDT, whereas dieldrin remained below detection limits. During the study period,
the mean values observed for total HCH, DDT and endosulfan were 87.6, 848.2, and 27.4 ng/L and 99.8, 275.3 and 164.2 ng/L,
respectively, for Ambala and Gurgaon districts. In the case of Hisar district, the values were 78.5, 115.9, and 53.0 ng/L,
respectively. During the study period, 37% of the samples exceeded the total pesticide level of 500 ng/L indicated in the
EECD directive for drinking water. Seasonal variations of pesticide residues were also observed during the study period. 相似文献
716.
Caetano M Bernárdez P Santos-Echeandia J Prego R Vale C 《Environmental monitoring and assessment》2012,184(11):6541-6552
Short-sediment cores and flooding water were collected at 0, 5, 15, 25 and 50?min of tidal inundation in the two sites colonised by pure stands of Spartina maritima (low marsh) and Sarcocornia fruticosa (high marsh) from the Rosário salt marsh (Tagus estuary, SW Europe). Concentrations of NH (4) (+) , NO (3) (-) +?NO (2) (-) and HPO (4) (2-) , Fe and Mn were measured in tidal flooding water and pore water. Flooding water is enriched in nutrients, particularly ammonium due to local discharge of untreated urban effluents. Nevertheless, NH (4) (+) and NO (3) (-) +?NO (2) (-) concentrations in flooding waters at t?=?5?min (NH (4) (+) =?246?±?7?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. fruticosa and NH (4) (+) =?256?±?8?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. maritima) rose sharply at both vegetated sites. An increase was also registered for HPO (4) (2-) and total dissolved Fe although the subsequent decrease was smoother. Advective transport induced by the two daily pulses of inundation is several orders of magnitude higher than the diffusive fluxes during submerged periods. In addition, solutes are exported from the sediment with the inundation and imported in submerged periods. The exported amount of inorganic nitrogen during tidal inundation (export of 3,200?μmol?N?m(-2)?day(-1)to the water column), is not counterbalanced by the sink of -290?μmol?N?m(-2)?day(-1) occurred during the submerged period. 相似文献
717.
This study is an assessment of the possible effects of the dredging project on the water quality of the surrounding environment. Water quality data for the Bonny offshore river were collected. The parameters assessed were temperature, dissolved oxygen (DO), pH, biochemical oxygen demand (BOD), total dissolved solids (TDS), total suspended solids (TSS), nitrogen as nitrate, and phosphate. The concentrations of TDS, TSS, and nitrate far exceeded the permissible standard. There were significant differences between the dry and rainy season values of BOD5, TDS, TSS, nitrate, and phosphate. Also, the sediment physicochemical analysis indicated the presence of heavy metals such as Pb, Fe, Cd, Zn, Cr, and elements such as Ca, K, and Na. Following an assessment of the potential impact of the project using interaction matrix and checklist questionnaires, results showed that the major physicochemical parameters influenced by dredging are DO, TDS, TSS, heavy metals and calcium, potassium, and sodium. Mitigation measures for eliminating or reducing the negative impacts of dredging are presented. 相似文献
718.
Large and mesoscale meteo-oceanographic patterns in local responses of biogeochemical concentrations
de Oliveira MM Pereira GC de Oliveira JL Ebecken NF 《Environmental monitoring and assessment》2012,184(11):6935-6956
Investigations surrounding the variability of productivity in upwelling regions are necessary for a better understanding the physical-biological coupling in these regions by monitoring systems of environmental impacts according to the needs of the regional coastal management. Using a spatial and temporal database from National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric (NCAR) Research reanalysis, Quick Scatterometer vector wind, and surface stations from the Southeast coast of Brazil, we investigate the meteorological influences due to the large-scale systems in the variability of the nutrient and larvae concentration, and chlorophyll a, describing statistically relationships between them in upwelling regions. In addition, we used multivariate analysis, such as PCA and clustering to verify spatial and temporal variances and describe more clear the structure and composition of the ecosystem. Correlation matrix analyses were applied for different water masses present in the study area to identify the relations between physical and biogeochemical parameters in a region, where frequently upwelling occur. Statistical approaches and seasonal variability show that the period of November to March is more sensitive to nutrients (1.20?mg/m(3) for chlorophyll a, 2.20?μmol/l for total nitrogen and 5.5?ml/l for DO) and larvae concentrations (120 org/m(3) for most of the larvae, except for cirripedia that presented values around 370 org/m(3)) relating to the influence of large and mesoescale meteorological patterns. The spatial and temporal variables analyzed with multivariate approach show meaningful seasonality variance of the physical and biological samples, characterizing the principal components responsible for this variance in spring and summer (upwelling period), emphasizing the monitoring of species as crustaceans and mussels that are present in the local economy. Then, the spring and summer season are characterized by high productivity due to the occurrence of upwelling in this period. 相似文献
719.
Nagaraja P Prakash JS Asha SC Bhaskara BL Kumar SA 《Environmental monitoring and assessment》2012,184(10):5983-5988
A rapid, simple, accurate, and sensitive visible spectrophotometric method for the determination of trace amounts of hydrogen peroxide in acidic buffer medium is reported. The proposed method is based on the oxidative coupling of Ampyrone with dibenzazepin hydrochloride by hydrogen peroxide in the buffer medium of pH?4.0 which is catalyzed by ferrous iron. The blue-colored product formed with maximum absorption at 620?nm was found to be stable for 2?h. Beer's law is obeyed for hydrogen peroxide concentration in the range of 0.03-0.42?μg?ml(-1). The optimum reaction conditions and other important optical parameters are reported. The molar absorptive and Sandell's sensitivity are found to be 5.89?×?10(4)?mol(-1)?cm(-1) and 0.57?g/cm(2), respectively. The interference due to diverse ions and complexing agents was studied. The method is successfully applied to the determination of hydrogen peroxide in green plants satisfactorily. 相似文献
720.
Sankaran S Sonkamble S Krishnakumar K Mondal NC 《Environmental monitoring and assessment》2012,184(8):5121-5138
This paper deals with a systematic hydrogeological, geophysical, and hydrochemical investigations carried out in SIPCOT area in Southern India to demarcate groundwater pollution and saline intrusion through Uppanar River, which flows parallel to sea coast with high salinity (average TDS 28, 870 mg/l) due to back waters as well as discharge of industrial and domestic effluents. Hydrogeological and geophysical investigations comprising topographic survey, self-potential, multi-electrode resistivity imaging, and water quality monitoring were found the extent of saline water intrusion in the south and pockets of subsurface pollution in the north of the study area. Since the area is beset with highly permeable unconfined quaternary alluvium forming potential aquifer at shallow depth, long-term excessive pumping and influence of the River have led to lowering of the water table and degradation of water quality through increased salinity there by generating reversal of hydraulic gradient in the south. The improper management of industrial wastes and left over chemicals by closed industries has led surface and subsurface pollution in the north of the study area. 相似文献