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151.
This study investigated the anoxic and aerobic phosphate uptake and release reactions and the fraction of denitrifying phosphate-accumulating organisms (DPAOs) under various initial chemical oxygen demand (COD) and residual COD conditions. The results showed that DPAOs and non-DPAOs could release phosphate when high soluble COD was present. Consequently, the phosphate-uptake potential was dynamic and increased when the initial COD increased, the initial polyhydroxyalkanoates (PHA) increased, and the residual COD decreased. Furthermore, the electron acceptor (oxygen of nitrate) has more significant influence on the phosphate uptake/release characteristics, while the residual COD concentrations have little influence on that. The fraction of DPAOs to phosphate-accumulating organisms was 42% when the initial PHA storage was enough by both DPAOs and non-DPAOs. This was closely related to the relative phosphate uptake (47%) in the anoxic zone of the process. 相似文献
152.
Sara Kaffe M.D. Carol Eliasen Livia Wan Norman Charles Valerie Jansen M. Alba Greco Lillian Y. F. Hsu 《黑龙江环境通报》1989,9(12):857-861
68,XX triploidy was found in the amniotic fluid cell culture of a 40-year-old patient. Elective termination of the pregnancy revealed a fetus with multiple congenital anomalies. While this case does show some common features with monosomy X, a greater similarity to the triploidy syndrome is observed. 相似文献
153.
The frequency of mosaicism and pseudomosaicism in the prenatal diagnosis of cytogenetic disorders is reported, based on 3000 pregnancies studied in our laboratory. Diagnosis of true mosaicism was only made when an abnomality was detected in two or more independent cultures established from an amniotic fluid sample. On this basis, 0.37 per cent of all cases were diagnosed as true mosaics. 1.07 per cent of all cases had pseudomosaicism involving more than one cell from the same culture with an identical abnormality. 4.13 per cent of cases had a single abnormal cell with an extra chromosome, loss of a sex chromosome (or part of a sex chromosome), or translocation. Details of the outcome and follow-up of cases is given. Particularly problematical were cases where multiple cells from one culture contained an abnormality which could have been clinically significant. A crude estimate of the extent to which true mosaicism might currently be misinterpreted as pseudomosaicism or entirely missed has been made, based on data from the U.S. survey (Hsu and Perlis, in press). It was concluded that even when two, and if necessary a third culture is extensively analysed with an average of 24 cells per culture counted, at least 4.5 per cent of cases of true mosaicism may be completely missed and at least 7 per cent could be misdiagnosed as pseudomosaicism. There is an urgent need for improved laboratory techniques which allow growth of a greater number of cell colonies and therefore a more broadly based analysis. Detailed long term follow-up of prenatally diagnosed mosaics is also essential for assessing the clinical significance of the laboratory findings. 相似文献
154.
AdultActinopyga echinites (Jaeger) were collected from northern Taiwan in September 1989. Oocytes were induced to mature by bathing them in ovary juice (ovary-induced ova) or in 10–2
M dithiothreitol (DTT-induced ova). The percentage of germinal vesicle breakdown (GVBD) increased from 0.4 to 6.4% in the former treatment and to 84% in the latter. After artificial fertilization, the embryos were cultured in seawater (35 S) at 25 to 28°C. Larvae were fed with the algaIsochysis aff.galbana at 104–5 cells/ml. Larvae from ovary-induced ova developed faster (18 d to the doliolaria stage) and grew to a larger size (1.13 mm length) than those from DTT-induced ova (20 d to the doliolaria stage and 0.62 mm in length). On the twelfth day, larvae from ovary-induced ova bear lipid spheres. The number of spheres is positively correlated with larval size. Lipid spheres may provide nutrient reserves for larvae during metamorphosis. 相似文献
155.
We investigated the characteristics of ambient particles and their relationships with various environmental factors, including
gaseous pollutants (CH4, non-methane hydrocarbons (NMHC), total hydrocarbons (THC), NOx, CO, SO2), meteorological parameters
(humidity, temperature), and time (day/night, workday/weekend). We used an electrical low-pressure cascade impactor to measure
the number and size distributions of ambient particles (0.007–10 m) that were collected approximately 1 km northwest of Hsinchu
Science Park in Taiwan between February and May 2007. The number concentrations of particles were enhanced through photochemical
reactions during the day. In addition, high traffic flow during workdays increased the formation of particulates. Except for SO2, all of
the gaseous pollutants we studied (CH4, NMHC, THC, NOx, CO) correlated positively with the total number concentrations of ambient
particles during daytime, indicating that they might contribute to the particulate burden. The poorer relationship between the SO2 level
and the total number concentration of particles suggests that SO2 might participate indirectly in the nucleation process during particle
formation, The high enrichment factors for Zn, Pb, Cu, and Mn, which mostly comprised the ultrafine particles (diameter: < 0.1 m)
and fine particles (diameter: 0.1–1 m), presumably arose from emissions from traffic and high technology factories. Heterogeneous
reactions on solid particles might play a role in the removal of SOx and NOx from the atmosphere. Sulfides and nitrides can further
react with these local pollutants, forming specific Cu-containing compounds: CuO (39%), CuSO4 (34%), and Cu(NO3)2 (27%), within
the ambient particles in this industrial area. 相似文献
156.
Edwards DP Woodcock P Edwards FA Larsen TH Hsu WW Benedick S Wilcove DS 《Ecological applications》2012,22(2):561-571
A key driver of rain forest degradation is rampant commercial logging. Reduced-impact logging (RIL) techniques dramatically reduce residual damage to vegetation and soils, and they enhance the long-term economic viability of timber operations when compared to conventionally managed logging enterprises. Consequently, the application of RIL is increasing across the tropics, yet our knowledge of the potential for RIL also to reduce the negative impacts of logging on biodiversity is minimal. We compare the impacts of RIL on birds, leaf-litter ants, and dung beetles during a second logging rotation in Sabah, Borneo, with the impacts of conventional logging (CL) as well as with primary (unlogged) forest. Our study took place 1-8 years after the cessation of logging. The species richness and composition of RIL vs. CL forests were very similar for each taxonomic group. Both RIL and CL differed significantly from unlogged forests in terms of bird and ant species composition (although both retained a large number of the species found in unlogged forests), whereas the composition of dung beetle communities did not differ significantly among forest types. Our results show little difference in biodiversity between RIL and CL over the short-term. However, biodiversity benefits from RIL may accrue over longer time periods after the cessation of logging. We highlight a severe lack of studies investigating this possibility. Moreover, if RIL increases the economic value of selectively logged forests (e.g., via REDD+, a United Nations program: Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), it could help prevent them from being converted to agricultural plantations, which results in a tremendous loss of biodiversity. 相似文献
157.
Motivated by the problem of detecting spatial autocorrelation in increment- averaged data from soil core samples, we use the
Cholesky decomposition of the inverse of an autocovariance matrix to derive a parametric linear regression model for autocovariances.
In the absence of autocorrelation, the off-diagonal terms in the lower triangular matrix from the Cholesky decomposition should
be identically zero, and so the regression coefficients should be identically zero. The standard F-test of this hypothesis and two bootstrapped versions of the test are evaluated as autocorrelation diagnostics via simulation.
Size is assessed for a variety of heteroskedastic null hypotheses. Power is evaluated against autocorrelated alternatives,
including increment-averaged Ornstein-Uhlenbeck and Matérn processes. The bootstrapped tests maintain approximately the correct
size and have good power against moderately autocorrelated alternatives. The methods are applied to data from a study of carbon
sequestration in agricultural soils. 相似文献
158.
Shang Hwa Hsu Chun-Chia Lee Muh-Cherng Wu Kenichi Takano 《Journal of Loss Prevention in the Process Industries》2010,23(5):646-653
Organizational theorists have recently begun to pay research attention to the workforces of emerging countries in Asia, especially the greater China regions. However, little research has focused on the influence of organizational factors on safety in these countries. This study hypothesized that organizational factors, characterized as safety leadership perspective (management commitment, blame culture) and safety climate perspective (harmonious relationships), would influence group-level safety management, which would in turn influence individual level safety awareness and practices. To test this hypothesis, a safety climate questionnaire was distributed to ten Taiwanese plants in high-risk industries. Structural equation modeling (SEM) was used to analyze the linkages among organizational level factors, work-group-level factors, and workers’ safety awareness and practices. We found that safety leadership style and organizational harmony in Taiwanese high-risk industries can exert significant influences on work-group processes, which in turn have greater effects on individual safety awareness and practices. These findings and implications can serve as a basis for safety improvement in areas of the greater China region. 相似文献
159.
Combustion modeling and performance evaluation in a full-scale rotary kiln incinerator. 总被引:1,自引:0,他引:1
K S Chen W T Hsu Y C Lin Y T Ho C H Wu 《Journal of the Air & Waste Management Association (1995)》2001,51(6):885-894
This work summarizes the results of numerical investigations and in situ measurements for turbulent combustion in a full-scale rotary kiln incinerator (RKI). The three-dimensional (3D) governing equations for mass, momentum, energy, and species, together with the kappa - epsilon turbulence model, are formulated and solved using a finite volume method. Volatile gases from solid waste were simulated by gaseous CH4 distributed nonuniformly along the kiln bed. The combustion process was considered to be a two-step stoichiometric reaction for primary air mixed with CH4 gas in the combustion chamber. The mixing-controlled eddy-dissipation model (EDM) was employed to predict the conversion rates of CH4, O2, CO2, and CO. The results of the prediction show that reverse flows occur near the entrance of the first combustion chamber (FCC) and the turning point at the entrance to the second combustion chamber (SCC). Temperature and species are nonuniform and are vertically stratified. Meanwhile, additional mixing in the SCC enhances postflame oxidation. A combustion efficiency of up to 99.96% can be achieved at approximately 150% excess air and 20-30% secondary air. Reasonable agreement is achieved between numerical predictions and in situ measurements. 相似文献
160.
Threat of heavy metal pollution in halophytic and mangrove plants of Tamil Nadu, India 总被引:2,自引:0,他引:2
Mangrove and halophytic plants occur along the coastal areas of Tamil Nadu, south India and these plants have been used in traditional medicine for centuries. Heavy metals are known to pose a potential threat to terrestrial and aquatic biota. However, little is known on the toxic levels of heavy metals found in mangrove and halophytic plants that are used in traditional medicine in India. To understand heavy metal toxicity, we investigated the bioconcentration factors (BCF) of heavy metals in leaves collected from eight mangroves and five halophytes in the protected Pichavaram mangrove forest reserve in Tamil Nadu State, south India. Data presented in this paper describe the impact of essential (Cu, Fe, Mg, Mn and Zn) and non-essential/environmentally toxic trace metals (Hg, Pb and Sn) in mangrove and halophytic medicinal plants. The concentrations of Pb among 13 plant species were higher than the normal range of contamination reported for plants. The average concentration of Hg in the halophytic plants (0.43+/-0.37mug/g) was seven times higher than mangrove plants (0.06+/-0.03mug/g) and it indicated pollutants from industrial sources affecting halophytes more than mangroves. 相似文献