全文获取类型
收费全文 | 289篇 |
免费 | 1篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 26篇 |
环保管理 | 41篇 |
综合类 | 33篇 |
基础理论 | 64篇 |
污染及防治 | 75篇 |
评价与监测 | 32篇 |
社会与环境 | 19篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 15篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 35篇 |
2012年 | 11篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 25篇 |
2007年 | 9篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1976年 | 2篇 |
1971年 | 1篇 |
1966年 | 2篇 |
1963年 | 1篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有296条查询结果,搜索用时 218 毫秒
61.
Armijo de Vega C Ojeda Benítez S Ramírez Barreto ME 《Waste management (New York, N.Y.)》2008,28(Z1):S21-S26
Integrated waste management systems are one of the greatest challenges for sustainable development. For these systems to be successful, the first step is to carry out waste characterization studies. In this paper are reported the results of a waste characterization study performed in the Campus Mexicali I of the Autonomous University of Baja California (UABC). The aim of this study was to set the basis for implementation of a recovery, reduction and recycling waste management program at the campus. It was found that the campus Mexicali I produces 1ton of solid wastes per day; more than 65% of these wastes are recyclable or potentially recyclable. These results showed that a program for segregation and recycling is feasible on a University Campus. The study also showed that the local market for recyclable waste, under present conditions - number of recycling companies and amounts of recyclables accepted - can absorb all of these wastes. Some alternatives for the potentially recyclables wastes are discussed. Finally some strategies that could be used to reduce waste at the source are discussed as well. 相似文献
62.
63.
64.
A comparison of shell growth in Donax trunculus (collected between 1988 and 1990 of Cullera, Spain) has been carried out using an analysis of cohort progression in monthly length frequency distributions, hyaline surface shell growth rings and internal microgrowth bands. In the Mediterranean there are two periods of recruitment of D. trunculus, one in the summer (July to September) and the other in winter (December to February). Clams recruited to the population in winter display a clear cessation in shell growth during the following summer which may possibly be correlated with spawning, whereas individuals of the summer recruited cohort show no growth cessation the following summer and continue to deposit shell during this period. The normally opaque shell of D.trunculus reveals the presence of translucent hyaline growth rings when the shells are backlit by a strong light source, and these have been shown to be laid down in the shell during summer months. Formation of a hyaline ring is accompanied by a narrowing of the microgrowth patterns present in shell sections. Both the hyaline rings and the length frequency distributions have been used to determine the age and growth rate of D. trunculus. 相似文献
65.
Claire G Williams Shannon L LaDeau Ram Oren Gabriel G Katul 《Ecological applications》2006,16(1):117-124
Predicting forest-tree seed dispersal across a landscape is useful for estimating gene flow from genetically engineered (GE) or transgenic trees. The question of biocontainment has yet to be resolved, although field-trial permits for transgenic forest trees are on the rise. Most current field trials in the United States occur in the Southeast where Pinus taeda L., an indigenous species, is the major timber commodity. Seed dispersal distances were simulated using a model where the major determinants were: (1) forest canopy height at seed release, (2) terminal velocity of the seeds, (3) absolute seed release, and (4) turbulent-flow statistics, all of which were measured or determined within a P. taeda plantation established from seeds collected from wild forest-tree stands at the Duke Forest near Durham, North Carolina, USA. In plantations aged 16 and 25 years our model results showed that most of the seeds fell within local-neighborhood dispersal distances, with estimates ranging from 0.05 to 0.14 km from the source. A fraction of seeds was uplifted above the forest canopy and moved via the long-distance dispersal (LDD) process as far as 11.9-33.7 km. Out of 10(5) seeds produced per hectare per year, roughly 440 seeds were predicted to be uplifted by vertical eddies above the forest canopy and transported via LDD. Of these, 70 seeds/ha traveled distances in excess of 1 km from the source, a distance too great to serve as a biocontainment zone. The probability of LDD occurrence of transgenic conifer seeds at distances exceeding 1 km approached 100%. 相似文献
66.
Aušrinė Armaitienė Vadim L. Boldyrev Ramūnas Povilanskas Julius Taminskas 《Journal of Coastal Conservation》2007,11(1):13-22
The varied and very dynamic landscape with a high biological diversity is a distinctive feature of the Curonian spit at the
regional scale. Throughout the 20th century the main morphodynamic trend in the littoral of the Curonian spit was shoreline
grading on the lagoon side, whereas on the marine side the increasing erosion at the foot of the spit, and increasing accretion
at the head of the spit prevailed. The results of a discriminant analysis (Wilkes’ λ = 0.001626 and F = 29.267 when p < 0.001) show that sites with prevailing erosion, accretion and sediment input from the drifting dunes form regular inter-related
spatial structures in the littoral with distinctive resulting discontinuities of the sediment drift along the lagoon coast.
Dune littoral cells are characterized by Aeolian sediment input and distribution ‘down-drift’, (usually northwards) from the
source. The most likely changes in the current development trends of the lagoon shore zone of the Curonian spit are related
to expected climate changes and further slowing down of the dune drift. The probability of storms and ice-drift events, and
their impact on coasts is expected to increase as a result of climate change. The dune advance will gradually slow down, and
with it, the sand input to the coastal zone will decline. In this paper, we define integrated shoreline management as a system
of long-term shoreline management measures, which is based on a littoral cell approach and aimed at harmonizing human activity
in the coastal zone with the natural development of the shoreline. We propose an integrated management program for the lagoon
shoreline of the Curonian spit, which is site-specific for each littoral cell as a coastal management unit. Drifting dunes
and seaside beaches are the natural amenities, which are best known and best appreciated on the Curonian spit by 49% of the
respondents representing the total Lithuanian population. A responsible tourism development should be considered as the key
means for proper appreciation of the drifting dunes and natural coasts by society, which means to acknowledge and cherish
the aesthetic and conservation values of dune and coastal landscapes of the Curonian spit as a World Heritage Site. There
are at least two pre-conditions for this: (1) to provide visitors with sufficient information about diverse values and functions
of the Curonian dunes and coasts within a broader regional and global heritage conservation context; (2) to enable tourists
to enjoy the most impressive dune and coastal landscapes at close range. In this paper we propose to encourage active dune
tourism, to reintroduce grazing into the Curonian dune areas, to restore and to preserve the most impressive landscapes of
the highest white drifting dunes by bringing the blown out sand from the leeward foot of the dunes back to the crest artificially. 相似文献
67.
Open-path tunable diode laser absorption spectroscopy for acquisition of fugitive emission flux data
Thoma ED Shores RC Thompson EL Harris DB Thorneloe SA Varma RM Hashmonay RA Modrak MT Natschke DF Gamble HA 《Journal of the Air & Waste Management Association (1995)》2005,55(5):658-668
Air pollutant emission from unconfined sources is an increasingly important environmental issue. The U.S. Environmental Protection Agency (EPA) has developed a ground-based optical remote-sensing method that enables direct measurement of fugitive emission flux from large area sources. Open-path Fourier transform infrared spectroscopy (OP-FTIR) has been the primary technique for acquisition of pollutant concentration data used in this emission measurement method. For a number of environmentally important compounds, such as ammonia and methane, open-path tunable diode laser absorption spectroscopy (OP-TDLAS) is shown to be a viable alternative to Fourier transform spectroscopy for pollutant concentration measurements. Near-IR diode laser spectroscopy systems offer significant operational and cost advantages over Fourier transform instruments enabling more efficient implementation of the measurement strategy. This article reviews the EPA's fugitive emission measurement method and describes its multipath tunable diode laser instrument. Validation testing of the system is discussed. OP-TDLAS versus OP-FTIR correlation testing results for ammonia (R2 = 0.980) and methane (R2 = 0.991) are reported. Two example applications of tunable diode laser-based fugitive emission measurements are presented. 相似文献
68.
Chandra S Ram RN Singh IJ 《Journal of environmental biology / Academy of Environmental Biology, India》2004,25(3):239-249
The present study embodies the observations on duration (45, 75 and 105 days) dependent effects of toxicologically low concentration (16 ppm) of a carbamate pesticide, carbofuran, on first ovarian maturity with correlative recovery response by withdrawal of treatment for 30 days in virgin yearlings of common carp, Cyprinus carpio var. Communis. In control fish histological organization of ovary and changes in gonado-somatic index (GSI) revealed the initiation of oocyte differentiation and development at the commencement of experiment in December-January and peak of maturation with fully grown yolky oocytes was attained by the time of termination of experiment in the end of March. In carbofuran exposed groups ovaries exhibited retardation of development and growth evident by significantly decreased GSI and predominace of immature oocytes passing through nuclear-cytoplasmic degeneration of variable magnitude. Severity of degenerative changes was more pronounced with prolonged duration. In recovery group ovaries had experienced regeneration as clued by the presence of oocytes of differential stages including vitellogenic and fully grown oocytes. In liver histopathological changes coupled with significant decrease in hepato-somatic index (HSI) attributed hepatic inactivation in all exposure groups whereas in recovery group an increase in HSI value with marked sign of hepatic reactivation was evidenced. No significant change in values of condition (CF) and somatic condition (SCF) factors substantiated the over all normal health of fish. Lipid and water content of ovary, liver and muscle registered the significant decrease at 105th day of exposure with concomitant augmented value for recovery group. These observations suggest that the commercial formulation of carbofuran, even at this toxicologically low concentration, is equally capable of affecting the first ovarian maturity with associated physiological implications but with reversibility in toxicity by withdrawal of pesticide exposure attributing regeneration in affected organs in due course time. 相似文献
69.
Singh AK Kumar A Singh IJ Ram RN 《Journal of environmental biology / Academy of Environmental Biology, India》2005,26(3):557-565
Seasonal ovarian cycle, based on histophysiological changes, and correlative variations in liver were studied in an Indian major carp, Labeo rohita reared in captivity under ambient environmental conditions in Tarai region of Uttaranchal. The oocyte features used for marking ovarian cycle included nuclear-ooplasmic ratio, yolk vesicle incorporation into ooplasm, number and size of nucleolus and differentiation of follicular layer. Based on these features the ovarian cycle in L. rohita was divided into five phases i.e. resting, preparatory, pre-spawning, spawning and post-spawning/regression. The resting and preparatory phases were characterized by the dominating presence of chromatin-nucleolar and yolk-vesicle stage oocytes. The pre-spawning phase ovary was marked by the prevalence of yolk globule stage oocytes having cortical alveoli and differentiating follicular wall. The oocytes containing densely packed yolk-granules and large masses of yolk vesicles and also exhibiting germinal vesicle movement (GVM) signified the ovary of spawning phase. The ovary in regression phase contained pre-ovulatory atretic oocytes and significant number of oogonia. The histophysiological changes in liver showing augmented biosynthetic activity during preparatory and pre-spawning phases seemed well correlated with the gonadal development. The increasing water temperature and day-length apparently was favourable for the gonadal development in L. rohita. 相似文献
70.
Unai?IriarteEmail author Jon?I?aki?álvarez-Uriarte Rubén?López-Fonseca Juan?Ramón?González-Velasco 《Environmental Chemistry Letters》2003,1(1):57-61
The relatively recent discovery of disinfection by-products has driven the main regulatory organisms to set maximum contaminant
levels for certain substances in drinking water. Trihalomethanes can be deemed as the most important group of by-products
in chlorinated surface waters. The present work has focused on trihalomethane formation in a full-scale water treatment plant.
We studied the effect of several factors, including ozonation, on trihalomethane levels in chlorinated treated water. The
treatment scheme also includes an ozonation step.
Electronic Publication 相似文献