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311.
Monica R. Lara 《Marine Biology》2008,154(1):51-64
Larval fishes likely use a variety of settlement cues to locate and navigate toward the habitats they will inhabit as juveniles.
Information about the morphology and state of development of the sensory organs of larval stages of fishes provides insight
into their capabilities at the time of settlement. The peripheral olfactory organ of wild-caught late-stage larvae and early
juveniles and some adults of 14 species of the Caribbean reef fishes wrasses (Labridae), parrot fishes (Scaridae) and damselfish
(Pomacentridae) were examined using scanning electron microscopy and compared in terms of settlement specificity. Ages in
days after hatching and days post-settlement were determined from the otoliths. Morphology of the nares and the olfactory
epithelium are described for these species by stage. The separation of the anterior and posterior nares occurred before settlement
in the labrids but in some specimens of scarids this separation was not complete by the time of settlement. Densities of ciliated
and microvillous receptor cells and non-sensory ciliated epithelial cells were calculated. Densities of ciliated receptor
cells ranged from 0.389 μm−2 in a specimen of Thallasoma bifasciatum to 0.0057 μm−2 in Bodianus rufus and of microvillous receptor cells from 0.038 μm−2 in a Clepticus parrae juvenile to 0.266 μm−2 in a juvenile Doratonotus megalepis. Densities of non-sensory cilia, also associated with high olfactory ability, were also high. The olfactory organ in wrasses
is well developed prior to settlement and is comparable to that of adult fishes. The possible role of olfaction in larval
schooling, reef cue detection and orientation toward habitat at settlement is discussed.
相似文献
Monica R. LaraEmail: |
312.
Susan E. Ford V. Monica Bricelj Christophe Lambert Christine Paillard 《Marine Biology》2008,154(2):241-253
The known negative effects of shellfish toxin-producing dinoflagellates on feeding, burrowing and survival of some bivalve
mollusks has prompted questions concerning whether they might also impair the internal defense system of affected bivalves
and make them more susceptible to disease agents. The primary components of the cellular defense system are hemocytes. Many
toxic dinoflagellates are too large to be ingested whole by hemocytes and would most likely be exposed to intracellular toxins
only after the algae are consumed, broken down, and the water-soluble toxins, released. Therefore, we conducted a series of
experiments in which hemocytes from two suspension-feeding bivalves—the Manila clam, Ruditapes philippinarum, and the softshell clam, Mya arenaria—were exposed in vitro to filtered extracts of one highly toxic paralytic shellfish toxin (PST)-producing and one nonPST-producing
strain of Alexandrium tamarense (isolates PR18b, 76 ± 6 STXeq cell−1 and CCMP115, with undetectable PST, respectively). We measured adherence and phagocytosis, two hemocyte attributes known
to be inhibited by bacterial pathogens and other stressors. We found no measurable effect of a cell-free extract from a highly
concentrated suspension of the PST-producing strain on hemocytes of either bivalve species. Instead, extract from the nonPST-producing
strain had a consistent negative effect on both clams, resulting in significantly lower adherence and phagocytosis compared
to strain PR18b and filtered seawater controls. The bioactive compound produced by strain CCMP115, which has yet to be characterized,
may be similar to the PST-independent allelopathic compounds described for Alexandrium spp., which act on other plankters. These compounds and those produced by other harmful algae are known to cause immobilization,
cellular deformation and lysis of co-occurring target organisms. Thus, nonPST producing Alexandrium spp., which do not cause paralysis and burrowing incapacitation of clams, may still produce a compound(s) that has negative
effects not only on hemocytes, but on other molluscan cell types and their functions, as well. 相似文献
313.
In recent years, improvements in point-source depuration technologies have highlighted the problems regarding agricultural
nonpoint (diffuse) sources, and this issue has become highly relevant from the environmental point of view. The considerable
extension of the areas responsible for this kind of pollution, together with the scarcity of funds available to local managers,
make minimizing the impacts of nonpoint sources on a whole basin a virtually impossible task. This article presents the results
of a study intended to pinpoint those agricultural areas, within a basin, that contribute most to water pollution, so that
operations aimed at preventing and/or reducing this kind of pollution can be focused on them. With this aim, an innovative
approach is presented that integrates a field-scale management model, a simple regression model, and a geographic information
system (GIS). The Lake Vico basin, where recent studies highlighted a considerable increase in the trophic state, mainly caused
by phosphorus (P) compounds deriving principally from the intensive cultivation of hazelnut trees in the lake basin, was chosen
as the study site. Using the management model Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), the
consequences, in terms of sediment yield and phosphorus export, of hazelnut tree cultivation were estimated on different areas
of the basin with and without the application of a best management practice (BMP) that consists of growing meadow under the
trees. The GLEAMS results were successively extended to basin scale thanks to the application of a purposely designed regression
model and of a GIS.
The main conclusions can be summarized as follows: The effectiveness of the above-mentioned BMP is always greater for erosion
reduction than for particulate P reduction, whatever the slope value considered; moreover, the effectiveness with reference
to both particulate P and sediment yield production decreases as the slope increases. The proposed approach, being completely
distributed, represents a considerable step ahead compared to the semidistributed or lumped approaches, which are traditionally
employed in research into tools to support the decision-making process for land-use planning aimed at water pollution control. 相似文献
314.
AbstractObjective: Highly reclined postures may be common among passengers in future automated vehicles. A laboratory study was conducted to address the need for posture and belt fit in these seating configurations.Methods: In a laboratory vehicle mockup, the postures of 24 men and women with a wide range of body size were measured in a typical front vehicle seat at seat back angles of 23°, 33°, 43°, and 53°. Data were gathered with and without a sitter-adjusted headrest. Posture was characterized by the locations of skeletal joint centers estimated from digitized surface landmarks.Results: Regression analysis demonstrated that the pelvis rotated rearward and lumbar spine flexion decreased with increasing recline. The lap portion of the 3-point belt was more rearward relative to the pelvis in more-reclined postures, and the torso portion crossed the clavicle closer to the midline of the body. Regression equations were developed to predict posture and belt fit variables as a function of passenger characteristics, seat back angle, and the use of the headrest.Conclusions: Spine posture changes as the torso reclines in an automotive seat, and belt fit is altered by the change in posture. The results can be used to accurately position crash test dummies and computation human models and to guide the design of belt restraints. 相似文献
315.
Hadarits Monica Pittman Jeremy Corkal Darrell Hill Harvey Bruce Kristin Howard Allan 《Regional Environmental Change》2017,17(5):1515-1525
Regional Environmental Change - We develop and apply a synthetic framework for understanding potential adaptations to climate change in the Canadian agriculture sector through a case study of... 相似文献
316.
Changes in future potential distributions of apex predator and mesopredator mammals in North America
Regional Environmental Change - Climate change has determined shifts in distributions of species and changing climates are likely to continue to affect species in the future. In this study, we used... 相似文献
317.
318.
319.
Matthew P. Reed Sheila M. Ebert Monica L. H. Jones B.-K. Daniel Park Jason J. Hallman Rini Sherony 《Traffic injury prevention》2018,19(8):S70-S77
AbstractObjective: A test track study was conducted to quantify patterns of adult front seat passenger head motion during abrupt vehicle maneuvers.Method: Eighty-seven men and women with a wide range of body sizes and ages participated in data collection on a closed test track in a passenger sedan under manual control by a test driver. Because a primary goal of the study was to gather “unaware” data, the participants were instructed that the study was concerned with vehicle dynamics and they were required to read from a questionnaire taped to the top of their thighs as the drive began. The first event was a hard brake (approximately 1 g) to a stop from 35?mph (56 kph). Within the space of approximately 5?min the participants also experienced an aggressive lane change, a sharp right turn with simultaneous hard braking, and a second hard braking event. A Microsoft Kinect v2 sensor was positioned to view the area around the front passenger seat. Head location was tracked using the Kinect data with a novel methodology that fit 3D head scan data to the depth data acquired in the vehicle.Result: The mean (standard deviation) forward excursion of the estimated head center of gravity (CG) location in the first braking event was 135 (62) mm. The forward head CG excursion in the second braking event of 115 (51) mm was significantly less than that in the first, but the difference was small relative to the within-condition variance. Head excursion on the second braking trial was less than that on the first trial for 69% of participants. The mean maximum inboard head excursion in lane-change maneuvers was 118 (40) mm. Forward head excursions in braking were significantly smaller for older passengers and those with higher body mass index, but the combined factors accounted for less than 25% of the variance. Inboard head excursion in the lane-change event was significantly related to stature, but only about 7% of variance was related to body size. Head excursions for men and women did not differ significantly after accounting for body size.Discussion: This is the first quantitative occupant dynamics study to use a large, diverse sample of passengers, enabling the exploration of the effects of covariates such as age and body size.Conclusions: The data demonstrate that a relatively large range of head positions can be expected to result from abrupt vehicle maneuvers. The data do not support simple scaling of excursions based on body size. 相似文献
320.
We explored the overall acceptability of killing jaguars and pumas in different scenarios of people–big cat interactions, the influence of attitudes toward big cats on acceptability, and the level of consensus on the responses. Data were obtained from 326 self-administered questionnaires in areas adjacent to Intervales State Park and Alto Ribeira State Park. Overall, people held slightly positive attitudes toward jaguars and pumas and viewed the killing of big cats as unacceptable. However, individuals that held negative attitudes were more accepting of killing. As the severity of people–big cat interactions increased, the level of consensus decreased. Knowing whether killing a big cat is acceptable or unacceptable in specific situations allows managers to anticipate conflict and avoid illegal killing of big cats. 相似文献