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831.
Szakal C McCarthy JA Ugelow MS Konicek AR Louis K Yezer B Herzing AA Hamers RJ Holbrook RD 《Journal of environmental monitoring : JEM》2012,14(7):1914-1925
Despite best efforts at controlling nanoparticle (NP) surface chemistries, the environment surrounding nanomaterials is always changing and can impart a permanent chemical memory. We present a set of preparation and measurement methods to be used as the foundation for studying the surface chemical memory of engineered NP aggregates. We attempt to bridge the gap between controlled lab studies and real-world NP samples, specifically TiO(2), by using well-characterized and consistently synthesized NPs, controllably producing NP aggregates with precision drop-on-demand inkjet printing for subsequent chemical measurements, monitoring the physical morphology of the NP aggregate depositions with scanning electron microscopy (SEM), acquiring "surface-to-bulk" mass spectra of the NP aggregate surfaces with time-of-flight secondary ion mass spectrometry (ToF-SIMS), and developing a data analysis scheme to interpret chemical signatures more accurately from thousands of data files. We present differences in mass spectral peak ratios for bare TiO(2) NPs compared to NPs mixed separately with natural organic matter (NOM) or pond water. The results suggest that subtle changes in the local environment can alter the surface chemistry of TiO(2) NPs, as monitored by Ti(+)/TiO(+) and Ti(+)/C(3)H(5)(+) peak ratios. The subtle changes in the absolute surface chemistry of NP aggregates vs. that of the subsurface are explored. It is envisioned that the methods developed herein can be adapted for monitoring the surface chemistries of a variety of engineered NPs obtained from diverse natural environments. 相似文献
832.
Kevin Summers Andrew Robertson Barbara Levinson 《Environmental monitoring and assessment》2000,64(1):379-390
The U.S. Environmental Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) have formed a partnership to establish pilot sites for the development of a network known as the Coastal Intensive Site Network (CISNet). CISNet is composed of intensive, long-term monitoring and research sites around the U.S. marine and Great Lakes coasts. In this partnership, EPA and NOAA are funding research and monitoring programs at pilot sites that utilize ecological indicators and investigate the ecological effects of environmental stressors. NASA is funding research aimed at developing a remote sensing capability that will augment or enhance in situresearch and monitoring programs selected by EPA and NOAA. CISNet has three objectives: 1) to develop a sound scientific basis for understanding ecological responses to anthropogenic stresses in coastal environments, including the interaction of exposure, environment/climate, and biological/ecological factors in the response, and the spatial and temporal nature of these interactions, 2) to demonstrate the value of developing data from selected sites intensively monitored to examine the relationships between changes in environmental stressors, including anthropogenic and natural stresses, and ecological response, and 3) to provide intensively monitored sites for development and evaluation of indicators of change in coastal systems. 相似文献
833.
834.
Andrew M. Robbins Tara S. Stoinski Katie A. Fawcett Martha M. Robbins 《Behavioral ecology and sociobiology》2009,63(4):477-489
Socioecological models indicate that the group structure and female dispersal patterns of primates are determined primarily by the abundance and distribution of food, predation pressures, and infanticide risks. In response to those influences, females of folivorous primates are considered relatively free to disperse into groups with the optimal size and structure. Yet some folivores live in small groups despite a potentially higher risk of predation, an apparent inconsistency known as the folivore paradox. This paper examines the female dispersal of a folivorous primate, the Virunga mountain gorillas. Mountain gorillas currently have no natural predators, but this species presents a different version of the folivore paradox: why do 50–60% of females reside in smaller one-male groups despite a higher risk of infanticide? In this study, females left one-male groups more frequently than multimale groups, but transfer destinations were not consistently biased toward multimale groups and those groups did not have higher immigration rates. We found no evidence of dispersal to avoid feeding competition within large groups, even as they have become three to five times larger than average. Thus, the lack of a consistent bias toward multimale groups was not because they are typically larger than one-male groups. Instead, the apparent inconsistencies may reflect limited female transfer opportunities, other influences on dispersal, and possibly an evolutionary disequilibrium in which current behavior does not optimize fitness. 相似文献
835.
The source–pathway–receptor (SPR) approach to human exposure and risk assessment contains considerable uncertainty when using
the refined modelling approaches to pollutant transport and dispersal, not least in how compounds of concern might be prioritised,
proxy or indicator substances identified and the basic environmental and toxicological data collected. The impact of external
environmental variables, urban systems and lifestyle is still poorly understood. This determines exposure of individuals and
there are a number of methods being developed to provide more reliable spatial assessments. Within the human body, the dynamics
of pollutants and effects on target organs from diffuse, transient sources of exposure sets ambitious challenges for traditional
risk assessment approaches. Considerable potential exists in the application of, e.g. physiologically based pharmacokinetic
(PBPK) models. The reduction in uncertainties associated with the effects of contaminants on humans, transport and dynamics
influencing exposure, implications of adult versus child exposure and lifestyle and the development of realistic toxicological
and exposure data are all highlighted as urgent research needs. The potential to integrate environmental with toxicological
models provides the next phase of research opportunity and should be used to drive empirical and model assessments. 相似文献
836.
Allan Curtis Andrew Britton Jonathan Sobels 《Journal of Environmental Planning and Management》1999,42(1):5-21
Landcare is an Australian success story and an important example of the potential of state-sponsored community participation. An important trend encouraged by the lead agencies is for Landcare groups to be linked through so-called networks. Linking together may appeal to groups as a way of increasing their capacity to compete for scarce resources and enhance their impact on agencies, regional catchment committees and government. Network formation is also driven by government and agency demands for efficiency, accountability and effective regional planning. In this paper the authors draw on their 1997 study of the Ovens Valley Landcare Network in Victoria. This research suggested networks are important local organisations and enhance the impact of groups by improving inter-group communication and 'pulling down' resources. Network processes also contributed to robust, productive, agency-community partnerships and suggested participation can increase community influence on decision making and be compatible with adaptive management. 相似文献
837.
This paper presents the findings of a post-auditing study which compares the actual and predicted socio-economic impacts (including traffic) of a major power station construction project in the UK. An attempt is made to determine the accuracy of the predictions presented at the public inquiry into the development, drawing on the results of a developer-funded monitoring exercise undertaken for the duration of the eight-year construction programme. The study found that a very high proportion of testable predictions prepared prior to the inquiry could be audited; of these, 60% were either within predicted ranges or accurate to within 20% of predicted values. However, one in seven predictions had errors of more than 50%. The study revealed no consistent bias towards either under- or over-estimation of impacts. The paper explores the reasons for the predictive errors identified in the study; these include a range of project-specific and more generic factors, several of which are likely to be applicable to other large-scale construction projects. The study is particularly useful in the field of EIA because it relates to several weak areas in current practice: the assessment of socio-economic impacts, construction effects, and monitoring and auditing. 相似文献
838.
Depth and muscle temperature of Pacific bluefin tuna examined with acoustic and pop-up satellite archival tags 总被引:1,自引:0,他引:1
David J. Marcinek Susanna B. Blackwell Heidi Dewar Ellen V. Freund Charles Farwell Daniel Dau Andrew C. Seitz Barbara A. Block 《Marine Biology》2001,138(4):869-885
Six Pacific bluefin tuna were tracked with ultrasonic telemetry and two with pop-up satellite archival tags (PSATs) in the
eastern Pacific Ocean in 1997, 1998, and 1999. Both pressure and temperature ultrasonic transmitters were used to examine
the behavior of the 2- to 4-year-old bluefin tuna. The bluefin spent over 80% of their time in the top 40 m of the water column
and made occasional dives into deeper, cooler water. The mean slow-oxidative muscle temperatures of three fish instrumented
with pressure and temperature transmitters were 22.0–26.1 °C in water temperatures that averaged 15.7–17.5 °C. The thermal
excesses in slow-oxidative muscle averaged 6.2–8.6 °C. Variation in the temperature of the slow-oxidative muscle in the bluefin
was not correlated with water temperature or swimming speeds. For comparison with the acoustic tracking data we examined the
depth and ambient temperature of two Pacific bluefin tagged with pop-up satellite archival tags for 24 and 52 days. The PSAT
data sets show depth and temperature distributions of the bluefin tuna similar to the acoustic data set. Swimming speeds calculated
from horizontal distances with the acoustic data indicate the fish mean speeds were 1.1–1.4 fork lengths/s (FL s−1). These Pacific bluefin spent the majority of their time in the top parts of the water column in the eastern Pacific Ocean
in a pattern similar to that observed for yellowfin tuna.
Received: 4 April 2000 / Accepted: 25 October 2000 相似文献
839.
Abstract: Practical conservation activity is increasing globally and is being undertaken by many different government and nongovernmental organizations. In the majority of cases, justification for proposed actions is experience-based rather than evidence-based, action is often taken without monitoring or evaluation of effectiveness, and results are rarely widely disseminated. Conservation has been compared with medicine as a crisis discipline in which action is often required urgently in the absence of good information. The practice of medicine has recently gone through an effectiveness revolution that has improved the criteria upon which treatment strategies are based by progressing from reliance on personal experience to reliance on scientific evidence. We draw parallels between medicine and conservation and present a practical framework to encourage evidence-based conservation action. Our rationale is that conservation actions for which scarce resources are sought should be justified by good scientific evidence. In our view this will also encourage more research addressing practical issues in conservation management. 相似文献
840.
Need and nestmates affect begging in tree swallows 总被引:3,自引:0,他引:3
We conducted an experiment on nestling tree swallows (Tachycineta bicolor) to examine predictions from signalling models for the evolution of conspicuous begging behaviour. Specifically, we examined
the relationship between (1) nestling begging intensity and hunger, (2) begging intensity and parental provisioning and (3)
begging intensity and nestmate condition. Forty broods of 9-day-old nestlings were removed from their nests for 1 h and assigned
to one of the following three treatments: (1) all nestlings in the brood deprived of food (n = 13), (2) all nestlings in the brood fed (n = 11) or (3) half the nestlings in the brood deprived and half fed (n = 16). Videotapes before and after the treatments showed that begging intensity increased in broods in which all of the nestlings
had been deprived and decreased in broods in which all of the nestlings had been fed. Deprived nestlings in the half-and-half
treatment did not change their begging intensity in response to treatment, while fed nestlings in this treatment group showed
a decrease in begging intensity. Parent tree swallows increased their feeding rate to deprived broods and decreased their
rate to fed broods. Within broods, parents decreased their feeding rate to fed nestlings, but showed no significant change
in feeding to deprived nestlings. Our results suggest that begging intensity is influenced by hunger and that parents appear
to respond to variation in begging intensity. The begging of nestmates also appears to influence begging independently of
need. These results are consistent with predictions derived from signalling models of begging.
Received: 20 June 1997 / Accepted after revision: 19 January 1998 相似文献