全文获取类型
收费全文 | 982篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 22篇 |
废物处理 | 18篇 |
环保管理 | 148篇 |
综合类 | 285篇 |
基础理论 | 200篇 |
污染及防治 | 226篇 |
评价与监测 | 51篇 |
社会与环境 | 32篇 |
灾害及防治 | 7篇 |
出版年
2020年 | 10篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 15篇 |
2014年 | 28篇 |
2013年 | 77篇 |
2012年 | 27篇 |
2011年 | 44篇 |
2010年 | 27篇 |
2009年 | 34篇 |
2008年 | 38篇 |
2007年 | 42篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 38篇 |
2003年 | 23篇 |
2002年 | 28篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 19篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 25篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1968年 | 6篇 |
1965年 | 7篇 |
1964年 | 9篇 |
1963年 | 6篇 |
1962年 | 6篇 |
1961年 | 6篇 |
1960年 | 8篇 |
1959年 | 11篇 |
1957年 | 7篇 |
1956年 | 11篇 |
1954年 | 10篇 |
1939年 | 6篇 |
1924年 | 6篇 |
排序方式: 共有989条查询结果,搜索用时 15 毫秒
71.
72.
73.
Lionel Baldwin Joseph Palomba Jr. Captain Walter Schirra 《Journal of the Air & Waste Management Association (1995)》2013,63(8)
A panel discussion looking forward to the environment in the year 2000, was arranged by Lionel V. Baldwin, Program Chairman for APCA’s 67th Annual Meeting. To provide a lofty introduction of the subject he reached into outer space for a moderator—Captain Walter M. Schirra, one of the original astronaut team. 相似文献
74.
Walter A. Lyons Lars E. Olsson 《Journal of the Air & Waste Management Association (1995)》2013,63(11):876-881
A two-day field program in Chicago studied mesoscale pollution transport during typical lake breezes. Streamlines calculated from serial pibal data suggest that a nearly closed circulation cell traps pollutants emitted near a shore line. Optically tracked tetroons confirm the helical trajectory of air within the lake breeze regime. Pollutants released within the inflow layer move inland, rise in a narrow zone of updrafts (100 cm/sec) at the lake breeze front, advect lakeward in the return flow layer aloft, and then subside back down into the inflow layer. Pollution then fumigates back to the surface as the air returns inland a second time causing concentrations higher than would otherwise be expected. Spectral aerosol measurements (0.5-3.0 and 7.0-9.0 micrometer size ranges) made by an instrumented aircraft reveal a marked particle size sorting. 相似文献
75.
This study investigates whether departments performing the same functions in different firms incur similar changes in structural configuration in response to industry-wide stimuli. Based on the proposition that the context of functional departments is similar across firms, changes in differentiation, integration, and perspective are hypothesized. Managers' perceptions of the validity of a series of statements to conditions five to 10 years ago and to present conditions are contrasted and show statistically significant shifts in these structural configurations. This change is confirmed by the analysis of responses of other managers in different departments within the same firms. Correlation analysis shows significant agreement among alternative measures of the same aspects of structure, and significant comovement among different structural dimensions. The later result supports the quantum theory of organizations. 相似文献
76.
Kitta Rossi 《Safety Science》1995,20(2-3)
In 1990 the Scientific Committee on Occupational Health Nursing (SCOHN) of the International Commission on Occupational Health (ICOH) carried out a survey on the education of occupational health nurses (OHN) in various countries. A questionnaire with 23 questions was mailed to 50 countries.Replies were received form altogether 37 countries (74%). The length of the general nursing education varies from two to five years, being three years in 21 countries. In two European countries it is less than three years.Some special training in occupational health is included in the general nursing education in 14 countries. However, the length of this training varies considerably. The special training is the longest in Denmark, Finland and Norway.According to the answers, special postgraduate courses are organized in 21 countries. Training in occupational health is also included in the public health nursing education of 12 countries.University level programs on occupational health nursing are available in eight countries. Joint education on occupational health at university level has been organized for various professionals in 13 countries. The length of this education varies greatly from some months to several years. In four countries the length of this joint education is one academic year.General nursing education is the basic requirement for occupational health nurses in most of the countries surveyed. However, training in occupational health is not included in this education in most of the countries. Special postgraduate courses in occupational health are organized in 21 countries to OHNs who are employed in Occupational Health Services. There is an urgent need to develop the education of OHNs in most countries surveyed. 相似文献
77.
Peter M. Allen Jeffrey G. Arnold Walter Skipwith 《Journal of the American Water Resources Association》2002,38(5):1477-1492
ABSTRACT: Major erosion of urban stream channels is found in smaller basins in the North Texas study area with contributing drainage areas of less than ten square miles. Within these basins, four basic channel types are identified based on bed and bank lithologies: alluvial banks and bottoms, alluvial banks and gravel bottoms, alluvial banks with rock bottoms, and rock banks with rock bottoms. Most channels (75 percent) have alluvial banks with gravel or rock bottoms. Channel slopes are steep (.38 to.76 percent). Rock consists predominantly of shale and limestone. Channel cross sections are divided into the following four zones based on weathering, scour and entrainment mechanisms: soil zone, slake zone, rock zone and bed material zone. Erodibility of the channels is determined using multiple techniques including reach hydraulics and stream power computations, submerged jet testing, slab entrainment thresholds, and slake durability rates. Procedures are based on both empirical and modeled time series estimates of channel erosion. Field and modeled results support rates of erosion of up to four inches per year. Rates are tied to flow regime, climate, and type of channel bed and banks. 相似文献
78.
Since the end of the 1970s, the southern European countries have shown an exceptional reduction in fertility rate. From the
highest levels among the developed nations, these countries dropped beneath the substitution rate level: in Greece there is
an average of about 1.5 children per woman, and Italy (starting three to four years ago), with 1.3 children per woman, is
now the country with the lowest fecundity rate in the world. Land-use planning in southern European small islands therefore
requires substantial revision. In the areas where western civilization began, which are highly populated and have a long history,
cultural and ethnic aspects of tradition are fundamental to environmental management and to the defense of historical heritage.
They also place a strong value on sustaining tourism, the most relevant economic activity, that allows them to survive and
maintain a high welfare level. For some decades they have had populations with a marked presence of young people and high
emigration rates, but now they are fast becoming dominated by the elderly and must prepare for a period of fast reduction
in youth of the workforce, while the peripheral areas of Asia and Africa are entering a sudden demographic growth phase.
The demographic structure has also been deeply altered both by previous migrations and by random variations, as usually happens
in all small communities. Social services for younger and older people have had to be adapted rapidly, reorganizing high-school
management, hospital and health-care structures, in-house assistance, and so on. There is a need to rethink the job market
and favor the immigration of highly specialized workers, which is a necessity for technical evolution. Sustainable development
is constrained nowadays not only by the scarcity of natural resources, but also by the quality and quantity of human resources.
Proper policies for population and land-use planning are highly correlated factors; they have to be considered with respect
of these new, rapid demographic changes. 相似文献
79.
80.