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721.
The Consistency of Extinction Risk Classification Protocols 总被引:1,自引:0,他引:1
TRACEY J. REGAN MARK A. BURGMAN† MICHAEL A. McCARTHY ‡ LAWRENCE L. MASTER§ DAVID A. KEITH GEORGINA M. MACE†† SANDY J. ANDELMAN‡‡ 《Conservation biology》2005,19(6):1969-1977
Abstract: Systematic protocols that use decision rules or scores are seen to improve consistency and transparency in classifying the conservation status of species. When applying these protocols, assessors are typically required to decide on estimates for attributes that are inherently uncertain. Input data and resulting classifications are usually treated as though they are exact and hence without operator error. We investigated the impact of data interpretation on the consistency of protocols of extinction risk classifications and diagnosed causes of discrepancies when they occurred. We tested three widely used systematic classification protocols employed by the World Conservation Union, NatureServe, and the Florida Fish and Wildlife Conservation Commission. We provided 18 assessors with identical information for 13 different species to infer estimates for each of the required parameters for the three protocols. The threat classification of several of the species varied from low risk to high risk, depending on who did the assessment. This occurred across the three protocols investigated. Assessors tended to agree on their placement of species in the highest (50–70%) and lowest risk categories (20–40%), but there was poor agreement on which species should be placed in the intermediate categories. Furthermore, the correspondence between the three classification methods was unpredictable, with large variation among assessors. These results highlight the importance of peer review and consensus among multiple assessors in species classifications and the need to be cautious with assessments carried out by a single assessor. Greater consistency among assessors requires wide use of training manuals and formal methods for estimating parameters that allow uncertainties to be represented, carried through chains of calculations, and reported transparently. 相似文献
722.
为探究渤海北部海上油气区及周边近岸海域典型芳香烃类化合物污染状况,2015年5月现场采集了32个站位的海水样品,针对7种苯系物(BTEX)和17种多环芳烃(PAHs)进行测定,并采用商值法和毒性当量法对污染物开展单一和联合生态风险评估。结果显示,研究海域海水中7种苯系物总含量范围为65.1~222.6 ng·L~(-1),以甲苯含量最高,表层含量略低于底层,油气区平均含量低于周边近岸,受到陆源污染输入的影响特征明显。表层海水中ΣPAHs含量范围为98.9~356.0 ng·L~(-1),平均值为184.5 ng·L~(-1),以低环芳烃占优势,总体处于中等水平,比值法判定该海域PAHs可能主要来源于石油及其加工产品。该海域海水中苯并(a)芘的风险商RQ值大于0.1,表现出低度风险,其余3种处于可接受水平。4种芳香烃类化合物联合生态风险等级为低度风险,对生态系统具有潜在的不利影响,但不同区域仍存在一定差异性,海上石油开采与陆源输入是影响该海域个别区域生态风险较高的重要因素。 相似文献
723.
Charles R. Kratzer William Dritschilo Lee J. Hannah Marlene A. Broutman 《Journal of the American Water Resources Association》1985,21(4):565-572
ABSTRACT: An input-output model was developed to predict changes in Salton Sea salinity and water level until the year 2000 due to proposed water conservation efforts and geothermal and solar pond energy developments. The model SALINP provided good agreement with the observed salinities for 1960–80. While SALINP was not overly sensitive to one-year changes in any of the major inputs, a change in the historical means of the Imperial Valley runoff and evaporative loss inputs produced a significant effect on future predictions. The proposed water conservation measures caused the predicted Salton Sea salinity for 2000 to greatly exceed 40,000 ppm, the level at which adverse effects to wildlife are believed to occur. The possible geothermal development also produced predicted salinities considerably above 40,000 ppm. The salinity predictions for solar ponds by themselves and in conjunction with geothermal development were below 45,000 ppm for 2000. The solar pond and geothermal combination also resulted in a predicted lowering of the “natural” water level by 5 to 7 feet by 2000. 相似文献
724.
Virginia C. Welford Richard A. Block Jonathan W. Bulkley 《Journal of the American Water Resources Association》1987,23(5):803-807
ABSTRACT: The production of a documentary video in a graduate seminar offers advantages over the traditional term paper. These advantages derive from the nature of the videotape medium. The most distinct difference between a written document and a video production is the use of the video camera to record events. In using the camera, the student is required to become involved both in front of the video camera, for example, as an interviewer, and behind the camera as a camera operator. Next, as an editor, the student is required to review the events that she/he has taped for inclusion in the final product. By participating in these three roles, the student has the opportunity to learn interviewing skills while interacting with professionals in the field, to learn videotaping skills, and to see him/herself as he/she appears to others. The student can use the video feedback to improve his/her professional presentation; posture, dress, gestures, speech, and facial expressions all have an impact on how we are perceived by others. Additionally, the painstaking process of reviewing the taped material leads to an intimate knowledge of the topic, and the process of choosing portions out of entire interviews hones the ability to select the crucial or central themes and ideas from any discussion. Finally, the power of video lies in its ability to communicate information to a wide audience. Although the nature of video for the general public does not permit highly detailed or rigorous coverage of any topic, it is a major source of information. Accordingly, video is an important tool that can be used to inform the public about the importance of wise water resource management. 相似文献
725.
To improve the present national and local sustainable planning capability for the coastal zone a GI application for the Italian
Coastal Susceptibility Assessment was planned within an institutional agreement between ENEA and the Land Defence Service
of the Italian Ministry of Environment. Taking into account previous European actions a suitable methodology to assess, in
a quantitative way, the susceptibility of beaches to be eroded has been set up.
The methodology balances the coastline trend as evaluated for a defined time period with the present coastal areas morphology
and land use, this in order to derive a value that expresses the evolutionary process in terms of probability of the loss
of goods within the ‘Homogeneous Coastal Tracts’.
The trend in the movement of the sea-land line has been used asgeo-indicator of a complex dynamic balance that refers both to marine and inland systems, and a vector GI application was built and locally
applied in southern Italian coastal areas.
The present shoreline position and some other information describing the intrinsic beach morphologies, and having significance
for the coastal erosion hazard assessment, have been derived from the national 1∶10.000 ortho-images of the National Cartographic
Reference System provided by the Italian Ministry of Environment. The illustrated GI application— CoSTAT—keeps the nominal
scale of all data collected or produced. In this analysis the coastal dune presence is analysed as factor limiting coastal
erosion susceptibility. Applying a matrix calculation a quantitative evaluation of erosion susceptibility degree was achieved
and plans were made to develop new information for a suitable use of Italian coastal areas.
The work describes the methodology, the conceptual frame-work and the results of a local application. 相似文献
726.
《Chemosphere》2002,49(10)
The distribution coefficients (Kd) and desorption rates of 137Cs and 241Am radionuclides in bottom sediments at different locations in the Black Sea were studied under laboratory conditions. The Kd values were found to be 500 for 137Cs and 3800 for 241Am at the steady state and described exponential curves. Rapid uptake of the radionuclides occurred during the initial period and little accumulation happened after four days. The desorption rates for 137Cs in different bottom sediments were best described by a three-component exponential model. The desorption half-times of 137Cs ranged from 26 to 50 d at the slow components. However, the desorption rate of 241Am described one component for all sediment samples and desorption half-time was found to be 75 d. In general, the results showed that the 241Am radionuclide is more effectively transferred to bottom sediment and has longer turnover time than 137Cs under Black Sea conditions. 相似文献
727.
Christine Pergent-Martini Gérard Pergent Eddy van der Maarel 《Journal of Coastal Conservation》2002,8(2):107-108
Two Special Features on integrated coastal zone management, especially along the Mediterranean Sea, result from a MeDCOAST
conference held in Hammamet (Tunisia). 20–25 October 2001. In this first Special Feature some papers are presented on ecological
and biological research related to integrated coastal zone management. All over Europe coastal environments are threatened
by human activities such as urbanization, industrial development, fisheries, aquaculture, recreation and tourism. Research
has to be developed that can be applied to similar case studies in different countries. Methods of monitoring are necessary
and baseline data have to be available in order to judge the significance of changes in the abjotic and biotic environment.
Examples of studies included in this Special Feature are mainly from southern banks of the Mediterranean Sea but there is
also an example from Estonia and one from the Canary Islands. 相似文献
728.
The potential impact of future sea level rise and climate change on 15 Welsh coastal dune systems has been investigated. Historical
Trend Analysis was undertaken using Ordnance Survey maps to quantify past shoreline change and to permit extrapolation of
past trends to predict possible future shoreline positions by 2080–2100. Predictions were also made using the Bruun Rule relationship
between sea level rise and shoreline response and an integrated method of assessment, Expert Geomorphological Assessment (EGA),
which provides a ‘best estimate’ of future coastline change, taking into account such factors as geological constraints, the
nature of past, present and future environmental forcing factors, and known coastal process–response relationships. The majority
of the 15 systems investigated experienced a net increase in dune area over the last 100–120 years. Only one (Whiteford Burrows)
experienced significant net area loss (>5 ha). EGA predictions suggest that several systems are likely to experience significant
net loss of dune habitat over the next century, whilst continued net gain is likely to occur for systems where sediment supply
rates remain high. Little net change is predicted in some systems. Considering the 15 dune systems together, it is considered
unlikely that net dune habitat loss will exceed net gain over the next 100 years provided that there are no major disruptions
to sediment supply and natural coastal processes. 相似文献
729.
Taxonomic Considerations in Listing Subspecies Under the U.S. Endangered Species Act 总被引:3,自引:0,他引:3
SUSAN M. HAIG†† ERIK A. BEEVER‡‡ STEVEN M. CHAMBERS† HOPE M. DRAHEIM‡ BRUCE D. DUGGER‡ SUSIE DUNHAM§ ELISE ELLIOTT-SMITH JOSEPH B. FONTAINE‡ DYLAN C. KESLER‡ BRIAN J. KNAUS§ IARA F. LOPES‡§§ PETE LOSCHL‡ THOMAS D. MULLINS LISA M. SHEFFIELD‡ 《Conservation biology》2006,20(6):1584-1594
Abstract: The U.S. Endangered Species Act (ESA) allows listing of subspecies and other groupings below the rank of species. This provides the U.S. Fish and Wildlife Service and the National Marine Fisheries Service with a means to target the most critical unit in need of conservation. Although roughly one-quarter of listed taxa are subspecies, these management agencies are hindered by uncertainties about taxonomic standards during listing or delisting activities. In a review of taxonomic publications and societies, we found few subspecies lists and none that stated standardized criteria for determining subspecific taxa. Lack of criteria is attributed to a centuries-old debate over species and subspecies concepts. Nevertheless, the critical need to resolve this debate for ESA listings led us to propose that minimal biological criteria to define disjunct subspecies (legally or taxonomically) should include the discreteness and significance criteria of distinct population segments (as defined under the ESA). Our subspecies criteria are in stark contrast to that proposed by supporters of the phylogenetic species concept and provide a clear distinction between species and subspecies. Efforts to eliminate or reduce ambiguity associated with subspecies-level classifications will assist with ESA listing decisions. Thus, we urge professional taxonomic societies to publish and periodically update peer-reviewed species and subspecies lists. This effort must be paralleled throughout the world for efficient taxonomic conservation to take place. 相似文献
730.
依据不同季节的调查,对渤海水体中颗粒有机碳(POC)的时空变化特征、碳库及影响因素进行对比研究.结果表明:春、夏、秋和冬季渤海调查海域颗粒有机碳的平均浓度分别为(338±146)μg/L、(491±136)μg/L、(358±228)μg/L和(2534±2601)μg/L,其中冬季渤海水体中POC浓度最高约是春季的7倍.不同季节渤海调查海域POC分布具有相似的规律,即由近岸浅水区向远岸逐渐降低,高值区多集中在调查海域北侧近岸、黄河入海口以及渤海湾等处.不同季节影响POC分布的因素不同,春、夏和秋季影响渤海调查海域POC分布的因素主要是陆源输入和浮游植物的生长繁殖,沉积物再悬浮是影响冬季渤海调查海域POC分布的主要因素.通过C/N比值探究不同季节渤海水体中POC来源发现,春季有45.3%、52.8%样品的C/N比值分别介于2.6~4.3和4~10之间,夏季有38.7%、32.3%样品的C/N比值分别介于2.6~4.3和4~10之间;秋季有84.4%样品的C/N比值介于4~10;而冬季有72.2%样品的C/N比值大于12,可见渤海水体中POC来源具有季节性差异,春季和夏季渤海调查海域POC主要来源于海洋生物的代谢活动,秋季渤海水体中POC的主要来源是浮游植物,冬季渤海POC的主要来源是再悬浮物作用下沉积物中保留下来的有机物.渤海POC碳库呈季节性变化,春、夏和秋季渤海调查海域POC碳库在6×105~7×105t范围内,冬季碳库最高,为2.5×106t. 相似文献