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941.
Steven W. Effler Mary Gail Perkins Harry Greer David L. Johnson 《Journal of the American Water Resources Association》1987,23(2):189-196
ABSTRACT: The effects “whiting” (CaCO3 precipitate) had on the optical properties and turbidity of the epilimnion of Owasco Lake, New York, were studied during the summer of 1985. Turbidity was partitioned according to “whiting” and non-“whiting” components utilizing a simple acidification procedure. Diffuse light attenuation was partitioned according to the attenuating processes of absorption and scattering. “Whiting” was present most of the summer. Two major “whiting” events occurred that caused major increases in turbidity and the attenuation of light. “Whiting” was the principle regulator of turbidity during the study; it caused increases in light attenuation by increasing light scattering. “Whiting” events can easily be mistaken by the public for phytoplankton blooms. 相似文献
942.
This paper offers a way of identifying fruitful research avenues through the maze of possibilities existing in the field of occupational stress. The field appears to be at a crossroads in which key choices will have to be made in the 1980s. The choices involve: How should we study stress? Who do we want to study? And what problems should we study? Central methodological challenges include: highlighting the relative value of various methods with respect to the level of explanation and the nature of the audience; examining the meaning and phenomenology of the stress experience; and evaluating the validity of measures in the hope of standardizing diagnostic instruments. Regarding research populations, more care must be devoted to selection of subjects. Subjects who are strained should be selected noting whether the state is acute versus chronic. Researchers should concentrate on blue collar jobs which are demanding but of low discretion; the long term unemployed; chronically threatened job incumbents; the wives of men who are themselves in stressful occupations; women in professional and executive roles; the wives of the unemployed; and single parent families in general. Stress problems worthy of study include: acute versus chronic states of stress; the role of the objective and subjective environment; the relationship between psychological strain and physiological mechanisms; coping behaviours; and the work, family and societal interface. The quality of knowledge of about each of these elements needs to be improved if we are to achieve a more comprehensive analysis of the stress process. 相似文献
943.
William K. Johnson 《Journal of the American Water Resources Association》1974,10(3):478-485
ABSTRACT: It is the thesis of this paper that plan formulation is both art and science, and that to improve formulation, to develop better alternatives, the planner needs to both improve his creative capability and to think more systematically. Research into creativity by psychologist and social scientist has identified four aspects of creativity: the creative process, the creative product, the creative person, the creative situation. A review of research results on each aspect suggests several ways in which planners can improve the creative dimension of plan formulation. To improve the rational aspects of plan formulation a way of thinking is presented in the form of a conceptual model to assist the planner in systematically developing a broader range of plans. The major components are inventory, forecast and synthesis. The model utilizes the concept of a production function to provide information about the resource, management practices and its use. 相似文献
944.
945.
Jeffrey Lee Robbins Church Duane Lammers Leon Liegel Mark Johnson Deborah Coffey Richard Holdren Donald Stevens Robert Turner Louis Blume 《Environmental management》1989,13(1):95-108
Through the Direct/Delayed Response Project (DDRP), the United States Environmental Protection Agency is attempting to assess the risk to surface waters from acidic deposition in three regions of the eastern United States: the Northeast Region, the Southern Blue Ridge Province, and the Mid-Appalachian Region. The central policy question being addressed by the DDRP is: Within the regions of concern, how many surface water systems (lakes, streams) will become acidic due to current or altered levels of acidic sulfur deposition, and on what time scales? The approach taken by the DDRP is to select a statistically representative set of watersheds in each region of concern and to project the future response of each watershed to various assumed levels of acidic deposition. The probability structure will then be used to extrapolate the watershed-specific results to each region. The data will be used also for statistical investigation of hypothesized relationships between current surface water chemistry and watershed characteristics. Because the needed terrestrial data base was not available, regional watershed surveys were conducted to meet the specific data needs of the DDRP. Maps (1∶24,000) of soils, vegetation, land use, depth to bedrock, and bedrock geology were made for each watershed. The soils were grouped into sampling classes based on their hypothesized response to acidic deposition. Randomized sampling of these classes provided regional means and variances of soil properties that can be applied to individual watersheds. Because of DDRP's need for consistency within and among regions, unique quality control/quality assurance activities were developed and implemented. After verification and validation, the DDRP data base will be made publicly available. This will be a unique and useful resource for others investigating watershed relationships on a regional scale. The results of these surveys and the conclusions of the DDRP will be presented in several future papers. The current paper gives an overview of the context, rationale, logistical considerations, and implementation of these surveys, with special emphasis on the field activities of watershed mapping and soil sampling. This discussion should be useful to those planning, implementing, and managing survey activities in support of regional assessments of other environmental concerns, who are likely to face similar choices and constraints. 相似文献
946.
Charles W. Slaughter Charles H. Racine Donald A. Walker Larry A. Johnson Gunars Abele 《Environmental management》1990,14(1):63-72
Use of off-road vehicles (ORVs) in permafrost-affected terrain of Alaska has increased sharply over the past two decades.
Until the early 1960s, most ORV use was by industry or government, which employed heavy vehicles such as industrial tractors
and tracked carriers. Smaller, commercial ORVs became available in the 1960s, with the variety and number in use rapidly increasing.
Wheeled and tracked ORVs, many used exclusively for recreation or subsistence harvesting by individuals, are now ubiquitous
in Alaska. This increased use has led to concern over the cumulative effects of such vehicles on vegetation, soils, and environmental
variables including off-site values.
Factors affecting impact and subsequent restoration include specific environmental setting; vegetation; presence and ice content
of permafrost; microtopography; vehicle design, weight, and ground pressure; traffic frequency; season of traffic; and individual
operator practices. Approaches for mitigating adverse effects of ORVs include regulation and zoning, terrain analysis and
sensitivity mapping, route selection, surface protection, and operator training.
We regret the untimely death of Gunars Abele on August 27, 1989; he was a valued colleague and good friend. 相似文献
947.
948.
Gary L. Johnson 《环境质量管理》1992,1(4):347-354
The need for a national consensus standard for quality assurance (QA) for environmental programs emerged from efforts to clean up sites contaminated by hazardous chemical and/or radioactive wastes. The waste management community has been using several different standards or sets of requirements for establishing the QA and quality control (QC) procedures for use during the cleanup of contaminated sites. Some of these requirements have been imposed by federal agencies, including the Department of Energy (DOE), the Department of Defense (DOD), the Nuclear Regulatory Commission (NRC), and the Environmental Protection Agency (EPA). Often, requirements have been chosen to fit a particular mission or regulatory requirements. The remediation and restoration of federally owned or operated hazardous waste sites has created a situation in which multiple organizations (including federal and state regulators, site operators, and remedial contractors) are overseeing or addressing the same technical problem, often at the same site, and using different QA requirements. The occurrence of multiple QA/QC requirements has resulted in costly and time-consuming duplication of effort. In addition, the perception of inconsistent and often conflicting requirements has created confusion and frustration. The need for a single set of QA/QC criteria to bring order and consistency to the application of QA in the environmental waste management area became increasingly clear, and led to the development of ANSI/ASQC E4, which may be approved and issued by this year. 相似文献
949.
950.
Henschel DB Fortmann RC Roache NF Liu X 《Journal of the Air & Waste Management Association (1995)》2003,53(11):1347-1354
Tests were conducted using 53-L dynamic chambers to determine airborne styrene emission rates over time from freshly copied paper. Copies were produced on a single photocopier using two toners manufactured for this copier but having different styrene contents. The resulting emission models were used to predict whether indoor styrene concentrations resulting from copied paper in a typical office might be significantly reduced by use of a low-emitting toner for a given copier. The styrene emissions were best represented by either a 3rd-order decay model or by a power law model having an exponent between 0.3 and 0.5 (R2 = 0.94-0.99). The two toners resulted in copied paper having significantly different styrene emissions (p < 0.01), with unit mass emissions over 1000 hr being nine times greater with the higher-emitting toner. But copied paper is predicted to produce peak indoor styrene concentrations in a typical office no more than 1% of the World Health Organization health-based guideline. Thus, for the toners considered here, indoor styrene exposures from copied paper appear to be too limited to provide incentive for switching to the lower-emitting toner. The ability to generalize these conclusions is limited by the fact that only one copier and two toners could be tested. 相似文献