首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   171篇
  免费   1篇
  国内免费   6篇
安全科学   6篇
废物处理   11篇
环保管理   12篇
综合类   36篇
基础理论   42篇
污染及防治   50篇
评价与监测   12篇
社会与环境   9篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   5篇
  2017年   4篇
  2016年   8篇
  2015年   5篇
  2014年   5篇
  2013年   12篇
  2012年   12篇
  2011年   20篇
  2010年   5篇
  2009年   8篇
  2008年   6篇
  2007年   12篇
  2006年   5篇
  2005年   5篇
  2004年   6篇
  2003年   10篇
  2002年   4篇
  2001年   5篇
  2000年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1982年   2篇
  1979年   1篇
  1976年   2篇
  1975年   1篇
  1966年   1篇
  1965年   2篇
  1964年   2篇
  1963年   1篇
  1961年   1篇
  1960年   1篇
  1959年   1篇
  1958年   2篇
排序方式: 共有178条查询结果,搜索用时 31 毫秒
121.
The ocean sunfish (Mola mola) is typically considered to feed on gelatinous zooplankton, but reports in the literature describe various benthic organisms being found in their stomachs. This might reflect ontogenetic dietary shift, as little was known about the foraging habit of this species. We examined their foraging habits using dietary analyses in combination with a behavioral study in Iwate, Japan (39°22′N, 141°58′E) from 2009 to 2010. Our stomach content analyses (n = 17, 31–250 cm total length) suggested that small sunfish (<50 cm) feed on benthic crustaceans, but large sunfish (>200 cm) feed on jellyfish. Larger sunfish showed higher values of both carbon and nitrogen stable isotope ratios. Deployment of accelerometers and animal-borne cameras on small sunfish in July (49–58 cm, n = 5) suggested their possibility of feeding, while they stayed near the seabed. This indicates that small sunfish might feed on benthic preys. Deployment of accelero-magnetometers on large sunfish in July (84–164 cm, n = 4) clarified that the large sunfish in July swam back and forth between the surface and deep water (>100 m). Temporary decelerations, which were considered to be associated with feeding of planktonic prey, were observed in deep water. Whereas deployment of accelero-magnetometers on large sunfish in November (105 cm, n = 3) showed several bursts, they swam within the mixed layer (0–100 m), which might be associated with chasing of rapid prey. These results suggest that ocean sunfish have heterogeneous diets depending on their body size and possibly season.  相似文献   
122.
The government of India decided to launch a project to implement 16 full-scale Upflow Anaerobic Sludge Blanket (UASB) reactors (with a total capacity of 598,000 m(3)/d) in the Yamuna River basin under its Yamuna Action Plan (YAP). A polishing pond called the Final Polishing Unit (FPU) was utilized for post-treatment. This paper evaluates the sewage treatment efficiency of the combined system of full-scale UASB reactors and polishing ponds under Indian climatic conditions. Results have shown that the effluent from the sewage treatment plants (STPs) investigated failed to comply with applicable discharge standards in terms of BOD, SS, and fecal coliform removal. Therefore, it is proposed that such proper operation and maintenance as removing excess sludge and scum be conducted in order to increase treatment efficiency. Moreover, trained and experienced workers are also required to operate and maintain the systems, along with a scientific approach.  相似文献   
123.
An application of treated sewage sludge on agricultural land has been widely accepted, as this method is simple and economical for disposal of wastewater residues. When applied properly on an agricultural land, sludge can replenish organic matter and nutrients in soil. Although sewage sludge has been used in agriculture in many parts of the world, its acceptability varies with different cultures and beliefs among farmers. Farmers’ concerns on sludge use are primarily due to its anthropogenic origin, pollutants that it carries, a general perception of sewage being dirty, and its offensive odor. This paper aims to investigate farmers’ perceptions on land application of treated sewage sludge on their farm. This study targeted two farming communities, namely, Anza and Beit Dajan villages, located in Jenin and Nablus districts in the West Bank, Palestine. In this study, a sample of 106 farmers were randomly selected and surveyed through a mixture of structured and open-ended questions. Results indicated that, overall, farmers have positive perceptions on land application of sludge. A majority of the farmers are in favor of the concept of sludge use when a planned wastewater treatment plant is constructed and it becomes operational. Results also indicate that a majority of the farmers are in favor of using sludge for fertilizing fruit trees, rather than growing vegetables and other plants in a greenhouse, and that many of them have knowledge of sludge properties and advantages and disadvantages of sludge use in agriculture. Despite the positive perceptions by the majority of farmers, a small fraction of the farmers are in disfavor of the use of sludge for the following reasons: psychological and social concerns, potential health risks, and their religious beliefs. Results further suggest that the land application of treated sewage sludge can be accepted by more farmers if the consumers are willing to buy agricultural products fertilized by sludge, sludge meets the public health requirements, and sludge is available at low costs. To improve farmers’ perceptions on the land application of sludge, several measures are recommended.  相似文献   
124.
BACKGROUND AND OBJECTIVE: Spills of heavy oil (HO) over the oceans have been proven to have an adverse effect on marine life. It has been hypothesized that exposure of early larvae of sinking eggs to HO leads largely to normal morphology, whereas abnormal organization of the developing neural scaffold is likely to be found. HO-induced disruption of the nervous system, which controls animal behavior, may in turn cause abnormalities in the swimming behavior of hatched larvae. To clarify the toxicological effects of HO, we performed exposure experiments and morphological and behavioral analyses in pufferfish (Takifugu rubripes) larvae. EXPERIMENTAL PROCEDURE: Fertilized eggs of pufferfish were exposed to 50?mg/L of HO for 8?days and transferred to fresh seawater before hatching. The hatched larvae were observed for their swimming behavior, morphological appearance, and construction of muscles and nervous system. RESULTS AND DISCUSSION: In HO-exposed larvae, we did not detect any anomaly of body morphology. However, they showed an abnormal swimming pattern and disorganized midbrain, a higher center controlling movement. Our results suggest that HO-exposed fishes suffer developmental disorder of the brain that triggers an abnormal swimming behavior and that HO may be selectively toxic to the brain and cause physical disability throughout the life span of these fishes.  相似文献   
125.

Purpose

We evaluate malathion toxicity to Japanese medaka (Oryzias latipes) juveniles by using a mass spectrometry combined with gas chromatography (GC/MS) metabolomics approach.

Methods

Medaka were exposed to low (L) and high (H) concentrations (nominally 20 and 2,000 ??g/L, respectively) of water-borne malathion. Metabolites were extracted from the fish, derivatized, and analyzed by GC/MS. Identified metabolites were subjected to one-way analysis of variance and principal component analysis (PCA). We examined the variations in the amounts of the metabolites during the exposure period.

Results and discussion

At 24 h, control, L, and H groups were separated along PC1, suggesting that the effects of malathion depended on exposure concentration. The PCA results at 96 h suggest that the metabolite profiles variations of the L and H groups differed, and thus that the effects of malathion in groups differed. At 24 h, the amounts of amino acids in both exposed groups were lower than the control group amounts, perhaps owing to accelerated protein synthesis. At 96 h, the amounts of almost all the amino acids increased in the L group but decreased in the H group relative to the control group amounts, suggesting the proteolysis occurred in the L group while protein synthesis continued in the H group, that the high malathion exposure affected the fish. In addition, at 96 h, gluconeogenesis may have been induced in the L group but not in H group.

Conclusions

Malathion exposure may have altered the balance between protein synthesis and degradation and induced gluconeogenesis in medaka. Our results suggest that metabolomics will be useful for comprehensive evaluation of toxicity.  相似文献   
126.
We characterized the ability of the cell free extract from polychlorinated dibenzo-p-dioxins degrading bacterium Geobacillus sp. UZO 3 to reduce even highly chlorinated dibenzo-p-dioxins such as octachlorodibenzo-p-dioxins in incineration fly ash. The degradation of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) as a model dioxin catalyzed by the cell free extract from this strain implicates that the ether bonds of 2,7-DCDD molecule undergo reductive cleavage, since 4′,5-dichloro-2-hydroxydiphenyl ether and 4-chlorophenol were detected as intermediate products of 2,7-DCDD degradation.  相似文献   
127.
In recent years, sludge generated in sewage treatment plants (STPs) and solid waste from livestock being utilized is useful for circulation of nourishment in farmlands as recycled organic manure (ROM). In this study, we determined the residue levels and patterns of 12 pharmaceutical products generated by human activity in the ROMs produced from human waste sludge (HWS), sewage sludge (SS), cattle manure (CM), poultry manure (PM), swine manure (SM) and horse manure (HM).The kind and number of pharmaceutical products detected in ROMs were different. Fluoroquinolones (FQs) were detected at high levels in HWS and SS samples. In addition, the detection frequency and concentration levels of sulfonamides (SAs) in PM and SM were high. Moreover, high concentrations of chlortetracycline (CTC) were found in only SM. These differences reflect specific adherence adsorption of the pharmaceutical products to different livestock and humans. Moreover, it was found that the concentrations of pharmaceutical products and fermentation levels of ROMs had significant positive correlation (r = 0.41, p = 0.024).When the fermentation test of ROM was conducted in a rotary fermentor in a lab scale test, the residue levels of pharmaceutical products decreased effectively except carbamazepine (CBZ). The rates of decrease were in the case of tetracyclines (TCs): 85-92%, FQs: 81-100%, erythromycine: 67%, SAs: 79-95%, trimethoprim: 86% and CBZ: 37% by 30 d. Pharmaceutical products that can be decomposed by fermentation process at the lowest impact of residual antibiotic activities may therefore be considered as environmentally friendly medicines.  相似文献   
128.
M. Sato  K. Wada 《Marine Biology》2000,137(4):705-714
 For three spider crabs (Tiarinia cornigera, Micippaplatipes and Pugettia quadridens quadridens), patterns of algal utilization for decorating were compared with the dynamics of algae on an intertidal rocky shore reef where the crabs co-occurred. T. cornigera and P. quadridens quadridens were most abundant from autumn to spring when the dominant algae (Boodleacoacta, Sargassum hemiphyllum, S. thunbergii and Corallina pilulifera) occurred in high coverage, while M. platipes was most abundant from spring to autumn. Monthly change of algae used for decorating was not correlated with algae growing in the crab habitat for T. cornigera, but for M. platipes, it was positively correlated for two algal species, and for P. quadridens quadridens, negatively correlated for one algal species. Each species of the spider crabs used some algal species preferentially for decoration. Decorating preference experiments conducted in the laboratory showed that M. platipes and P. quadridens quadridens exhibited similar preference to their algal utilization in the field, whereas for T. cornigera, algal preference in the experiment differed from utilization in the field. Comparisons between materials used for decoration and gut contents revealed that T. cornigera and M. platipes used algal species differently for decorating and feeding, while P. quadridens quadridens used the same algal species for both decorating and feeding. Different tactics for camouflage are discussed in terms of algal utilizations by the three majid species. Received: 25 September 1999 / Accepted: 22 June 2000  相似文献   
129.
The oxidative photodegradation behaviors of selected three coplanar polychlorinated biphenyls (PCBs), (CB77, CB81, and CB169) using titanium dioxide (TiO(2)) in water were investigated. The main purposes were to clarify the structural relation between the original PCBs and the intermediates derived by TiO(2) oxidation and to evaluate the estrogenic and thyroid hormonal activity in the treated three coplanar PCBs during the oxidative reactions. Approximately 90% of the three coplanar PCBs decomposed within 180 min. Intermediates from the decomposition of the three coplanar PCBs, such as some hydroxylated-PCBs (OH-PCBs), carboxylic intermediates, phenolic intermediates, and other intermediates produced by the cleavage of a benzene ring were identified and quantified. In the degradation pathways, the produced amounts of OH-PCBs increased within 60 min of irradiation time. The estrogenic activity and thyroid hormonal activity of the intermediates from the three coplanar PCBs in water at 0, 60, 120, 180 and 240 min of irradiation time were assessed by using a yeast two-hybrid assay system for human estrogen receptor alpha (hERalpha) and human thyroid hormone receptor alpha (hTRalpha). The maximal estrogenic activities were induced by the solutions of decomposed PCBs with irradiation time at 60-120 min similar and slightly lower than those after the irradiation time. We found that the solutions occuring during the irradiation times of 60-120 min contained several 4-OH-PCBs substituted with OH and Cl at para- and para'-positions having estrogenic activity. The thyroid hormonal activity was not detected in the decomposed three coplanar PCBs solutions.  相似文献   
130.
The present study measured the concentrations of 25 elements (Li, Mg, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) in the whole body of Isaza which is an endemic fish species to Lake Biwa, Japan, and compared the values in the specimens from the mass mortality Isaza (MMI) and normal fresh Isaza (NFI). The mean levels of Mn and total As (T-As) were relatively higher in MMI than in NFI. In the T-As, highly toxic inorganic As was detected in MMI. Moreover we found Mn and As concentrations in surface sediment were extremely high and temporally increased. From all these results, we could infer that the dissolution of Mn and As from surface sediment of Lake Biwa might have been one of the cause for the mass mortality of Isaza.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号