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361.
Stefan?MayerEmail author Magdalena?Twaru?ek Anna?B?ajet-Kosicka Jan?Grajewski 《Environmental monitoring and assessment》2016,188(3):154
Manual sorting of onions is known to be associated with a bioaerosol exposure. The study aimed to gain an initial indication as to what extent manual sorting of onions is also associated with mycotoxin exposure. Twelve representative samples of outer onion skins from different onion origins were sampled and analyzed with a multimycotoxin method comprising 40 mycotoxins using a single extraction step followed by liquid chromatography with electrospray ionization and triple quadrupole mass spectrometry. Six of the 12 samples were positive for mycotoxins. In those samples, deoxynivalenol, fumonisin B1, and B2 were observed in quantitatively detectable amounts of 3940 ng/g for fumonisin B1 and in the range of 126–587 ng/g for deoxynivalenol and 55–554 ng/g for fumonisin B2. Although the results point to a lower risk due to mycotoxins, the risk should not be completely neglected and has to be considered in the risk assessment. 相似文献
362.
Stefan H. Nessler Gabriele Uhl Jutta M. Schneider 《Behavioral ecology and sociobiology》2009,63(3):355-362
Sperm competition is a potent driving force in evolution leading to a remarkable variety of male adaptations that prevent
or reduce fertilization by rivals. An extraordinary defensive strategy against sperm competition has evolved in a number of
web spiders where males break off parts of their paired genitalia in order to obstruct the copulatory openings of females
(mating plug). A recent comparative analysis on the family level reports that genital damage is most frequent in species with
sexual cannibalism although, as yet, a functional association between sexual cannibalism and genital damage has not been found.
Using the moderately sexually cannibalistic orb-web spider Argiope lobata, we show for the first time that males cannibalized during their first copulation damaged their pedipalps with significantly
higher probability (74%) than males that escaped (15%). Of all males that damaged their genitalia, 44% were able to place
a genital fragment inside the copulatory opening of the female, resulting in a relatively low total plugging rate of 14%.
Successful obstruction of the female copulatory opening reduced the share of paternity of subsequent males (P
2 = 0.06%), thus, indicating that genital damage may have evolved as a response to sperm competition in this species as well.
However, the low incidence of successful plugging and the strong relationship between sexual cannibalism and genital damage
suggest that apart from paternity protection, the nature of genital damage in A. lobata is further shaped by sexual conflict or cryptic female choice. 相似文献
363.
Peter Miehle Michael Battaglia Peter J. Sands David I. Forrester Paul M. Feikema Stephen J. Livesley Jim D. Morris Stefan K. Arndt 《Ecological modelling》2009
In forest management and ecological research, consideration of the impacts and risks of climate change or management optimisation is complex. Computer models have long been applied as tools for these tasks. Process-based forest growth models claim to overcome the limitations of empirical statistical models, but the capacity of different process-based models and modelling approaches have rarely been compared directly. This study evaluates stepwise multiple regression models in comparison to four process-based modelling approaches (3-PG, 3-PG+, CABALA and Forest-DNDC) for greenfield predictions of Eucalyptus globulus plantation growth from 2 to 8 years after planting throughout southern Australia. 相似文献
364.
Energy dissipation, flow resistance and gas-liquid interfacial area in skimming flows on moderate-slope stepped spillways 总被引:2,自引:2,他引:0
With the re-evaluation and revision of a number of design floods, several embankment overtopping protection systems have been
developed and a common technique is the construction of a stepped spillway on the downstream slope. For such moderate slope
stepped channels, detailed air–water flow measurements were performed in a large facility with a focus on the rate of energy
dissipation, flow resistance, air–water interfacial areas and re-aeration rates. Past and present experimental results showed
a significant aeration of the flow. The median dimensionless residual head was about 3 × dc for the 21.8° sloping chute and smaller than that for flatter slopes (θ = 3.4° and 15.9°). The flow resistance results yielded an equivalent Darcy friction factor of about 0.25 implying a larger
flow resistance for the 21.8° slope angle than for smaller slope angles. The re-aeration rate was deduced from the integration
of the mass transfer equation using measured air–water interfacial areas and air–water flow velocities. The results suggested
an increasing re-aeration rate with increasing rate of energy dissipation. The stepped invert contributed to intense turbulence
production, free-surface aeration and large interfacial areas. The experimental data showed however some distinctive seesaw
pattern in the longitudinal distribution of air–water flow properties with a wave length of about two step cavities. While
these may be caused by the interactions between successive adjacent step cavities and their interference with the free-surface,
the existence of such “instabilities” implies that the traditional concept of normal flow might not exist in skimming flows
above moderate-slope stepped spillways. 相似文献
365.
Rajalakshmi M. Josiam Heinz G. Stefan 《Journal of the American Water Resources Association》1999,35(2):433-439
ABSTRACT: Theoretical equations that establish the relationship between sediment oxygen demand (SOD) in a lake and the flow velocity and dissolved oxygen concentration in the bulk water already exist. These theoretical equations for oxygen consumption in the sediment express biological consumption with Michaelis-Menten kinetics, and chemical consumption by a first order reaction. Data from laboratory experiments that were conducted to validate the theoretical equations also exist. These experiments were performed in a laboratory channel with well defined flow characteristics for three types of sediments. Herein, the theoretical equations are used to model the experimental data for the three types of sediments. The values used for the parameters in the theoretical equations are determined by iteration until a best fit is obtained for the relationship of SOD to flow velocity from both the theoretical model and experimental data. The goodness of fit is measured by the standard error of prediction and the regression coefficient. 相似文献
366.
Ohne Zusammenfassung
The online version of the original article can be found at 相似文献
367.
368.
Volker Berding Stefan Schwartz Michael Matthies 《Environmental science and pollution research international》1999,6(1):37-43
The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters
(inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation,
on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency.
The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity
was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters),
and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity
to 961, and the maximal dimension is 21. 相似文献
369.
Farkas J Peter H Christian P Gallego Urrea JA Hassellöv M Tuoriniemi J Gustafsson S Olsson E Hylland K Thomas KV 《Environment international》2011,37(6):1057-1062
The increasing number of nanomaterial based consumer products raises concerns about their possible impact on the environment. This study provides an assessment of the effluent from a commercially available silver nanowashing machine. The washing machine released silver in its effluent at an average concentration of 11μgL(-1), as determined by inductive coupled mass spectrometry (ICP-MS). The presence of silver nanoparticles (AgNPs) was confirmed by single particle ICP-MS as well as ion selective electrode measurements and filtration techniques. Size measurements showed particles to be in the defined nanosize range, with an average size of 10nm measured with transmission electron microscopy (TEM) and 60-100nm determined with nanoparticle tracking analysis (NTA). The effluent was shown to have negative effects on a natural bacterial community as its abundance was clearly reduced when exposed to the nanowash water. If washing machines capable of producing AgNPs become a common feature of households in the future, wastewater will contain significant loadings of AgNPs which might be released into the environment. 相似文献
370.
Harald G. Zechmeister Stefan Dullinger Gunda Koellensperger Siegrun Ertl Christian Lettner Karl Reiter 《Environmental science and pollution research international》2011,18(1):91-98