全文获取类型
收费全文 | 70篇 |
免费 | 1篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 1篇 |
环保管理 | 20篇 |
综合类 | 4篇 |
基础理论 | 15篇 |
污染及防治 | 17篇 |
评价与监测 | 8篇 |
社会与环境 | 3篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 10篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1956年 | 1篇 |
排序方式: 共有71条查询结果,搜索用时 15 毫秒
11.
Xiang Huiming Cheng Le Liu Weiye Wang Saier Zhang Yi Su Lianghu Tan Chaoqun Li Yuping 《Environmental science and pollution research international》2023,30(2):3056-3069
Environmental Science and Pollution Research - The properties of leachate from refuse transfer stations (RTSs) in rural China were indefinite. In this study, a total of 14 leachate samples from... 相似文献
12.
13.
14.
W. R. J. Dean S. J. Milton M. A. Du Plessis 《Environmental monitoring and assessment》1995,37(1-3):103-110
We used simple questionnaire surveys to obtain rough categorical information on the status of semiarid and arid rangelands in the Karoo, South Africa. We sent questionnaires to extension officers of the Department of Agricultural Development, asking them to rank the condition of the rangeland in their extension districts (usually about 500 farms) on a three- or five-point scale. The questionnaire also sought information on the possible reasons for changes in the condition of the rangelands; vegetation types most at risk on mismanaged rangelands; and changes in the status of plants, birds, and mammals. Extension officers rated 35% of the semiarid rangelands in southwestern South Africa (the Karoo and southern Kalahari Desert) as being in poor condition. There was some congruency between the perceived condition of the agricultural extension district and the percentage that the stocking rate had decreased. Rangeland condition in more arid areas tends to be poor. Stocking rates have decreased disproportionately more in arid areas than in the more mesic areas of southwestern South Africa. Grasses were rated as the most threatened group of plants, and succulents the least threatened group. Overgrazing in the past was considered to be the most important cause of present-day rangeland condition, followed by present overstocking of rangelands. Antelope were considered more threatened by rangeland management than mammalian carnivores. Avian raptors and bustards, gamebirds, and tortoises were all perceived to be threatened by rangeland mismanagement. 相似文献
15.
S. F. Goodburn J. R. W. Yates P. R. Raggatt C. Carr M. E. Ferguson-Smith A. J. Kershaw P. J. D. Milton Professor M. A. Ferguson-Smith 《黑龙江环境通报》1994,14(5):391-402
Over a 2-year period from January 1991 to December 1992, second-trimester maternal serum screening for Down's syndrome using alpha-fetoprotein (aFP), human chorionic gonadotrophin (hCG), and unconjugated oestriol (uE3) was made available to five health districts in East Anglia, with a total population of 1·2 million. Amniocentesis was offered when the risk of Down's syndrome at term was 1:200 or greater. 25359 singleton pregnancies were screened, representing an uptake of 77 per cent. The recall rate for the 24 per cent of women who had not had a dating scan prior to the test was 9·4 per cent compared with 3·9 per cent for those who had been scanned (P<0·0005). Seventy-five per cent (36/48) of Down's syndrome pregnancies were detected for a false-positive rate of 4·0 per cent. Twenty-five out of 36 of detected Down's syndrome pregnancies were dated by scan prior to sampling, and in the 11 remaining cases, the dates were confirmed by scan after a high-risk result was obtained. The exclusion of uE3 from the screening protocol would have reduced the detection rate to 52 per cent (25/48) for the same false-positive rate. Eighty-five per cent of women identified at high risk accepted the offer of an amniocentesis. Other fetal abnormalities detected were trisomy 18 (3), trisomy 13 (2), 45,X (6), 69,XXX (5), other chromosome abnormalities (9), open neural tube defects (26), hydrocephalus (7), abdominal wall defects (4), and steroid sulphatase deficiency (6). 相似文献
16.
David Milton Taub 《Behavioral ecology and sociobiology》1980,6(3):187-197
Summary Data are presented from a 15-month study on triadic male-infant interactions (agonistic buffering) among wild Barbary macaques, and the agonistic buffering hypothesis reevaluated. The sociometrics of triadic interactions derived from the distribution of 535 interactions among individually known adult and subadult males showed that there were significant individual male differences in the frequency of initating and/or receiving triadic interactions, but there were no such differences between the high and low ranking male subgroups (Tables 2–4).Males did not choose each other equally for triadic encounters. Each male had a different set of three other males (out of 11 possible) that he preferred to approach for a triadic encounter; and each male received triadic approaches essentially from only three males (Tables 4 and 5). Each male showed a specific preference for which infant to select for participation in the triad, and in fact, males who preferred one another for triads also preferred to use the same infant in these encounters. These males that preferred each other and the same infant both had a special care-taking relationship with that preferred infant (Tables 6–7).Possessing an infant per se seemed to be irrelevant in whether a male would approach or be approached for a triad. In 78% of all triads, males separated immediately after termination of the triad. When the agonistic buffering hypothesis is reexamined against the data in this study, it appears that it cannot adequately accommodate the thesis that it serves to regulate dominant/subordinate relations among males. Rather males choose to participate with each other in agonistic buffering because, and by means of, a shared, common, and special care-taking relationship with the same infant. The indiscriminate use of the terminology agonistic buffering to describe multiple-male/infant interactions in this species should be dropped. 相似文献
17.
Milton Feldstein 《Journal of the Air & Waste Management Association (1995)》2013,63(3):139-141
In January 1966, 483 randomly selected 1963-1966-model automobiles were inspected at the Cincinnati Vehicle Inspection Station to determine the effectiveness of their positive crankcase ventilation systems. All of these automobiles should have had crankcase ventilation systems installed in accord with the voluntary program of the automobile manufacturers. However, 48 of the automobiles inspected had no positive crankcase ventilation system. In addition, 27 cars were equipped with systems which could not readily be tested. Testing of the remaining 408 cars was performed with a combination pressure-vacuum gauge designed to measure the airflow in the crankcase. Results showed that 71% of the positive crankcase ventilation systems tested were operating satisfactorily and impending maintenance of systems was indicated for 29% of the automobiles tested. Although the systems of certain makes of cars performed considerably better than others, a definite decrease in system performance with increasing age and mileage was observed for the cars tested. The performance data indicate that the periodic maintenance required for positive crankcase ventilation systems is not being implemented. Only 47.5% of the drivers questioned were aware of the system and only 10% knew whether their system had been serviced. 相似文献
18.
S. J. Milton §§ W. J. Bond † M. A. Du Plessis † D. Gibbs ‡ C. Hilton-Taylor § H. P. Linder L. Raitt †† J. Wood ‡‡ J. S. Donaldson§ 《Conservation biology》1999,13(4):735-743
Abstract: A form of lowland, sandplain Fynbos restricted to the Cape Flats near the city of Cape Town is the South African vegetation type most threatened by urban and agricultural development. Cape Flats Fynbos remnants, totaling 4.8 km2 , contain 14 plant species endemic to the Cape Flats scattered through four protected areas and 11 unprotected vegetation fragments on public land. Despite their small size and management problems, the remaining protected areas are under pressure from the public and developers to function as "lifeboats," or places of safety, for attractive indigenous plant species from the unprotected areas destined for development because the popular perception is that any indigenous plant population threatened by habitat destruction should be saved by being transplanted into a protected area. The urgency for dealing with the issue of plant rescue in the Cape Town metropolitan area was the catalyst for a workshop held at the University of Cape Town in 1998 to develop protocols for Fynbos plant species translocations. We report on points raised by managers and academics at the workshop, including the selection of target taxa, individuals, and establishment sites, and methods for introduction, and present case histories illustrating possible solutions to the problems encountered. 相似文献
19.
Elwyn S. Krous Joseph P. Wagner Harold L. Parkinson Milton S. Sachs 《Journal of the American Water Resources Association》1971,7(4):810-822
ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied. 相似文献
20.
Since the mid-19th century settled livestock ranching has been the major form of land use in South Africa, occupying 68% of the land surface. Decreases in livestock densities and ranch numbers during the past century imply that carrying capacities for domestic herbivores are falling. Differences in carbon isotope signals with soil depth and abrupt shifts in dominant plant species across ranch boundaries reveal that southern African rangelands are changing. Case studies suggest ways to control altered grassland composition, bush encroachment in arid savanna, and dominance by toxic and halophytic shrubs in arid shrublands. But climatic and biological factors constrain rates of passive recovery, and guidelines for active restoration are poor and techniques costly. Moreover, conservation of remaining good rangeland is seldom enforced, and economic considerations usually outweight the land user's desire to sustain diversity and productivity. 相似文献