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Ivonne?MeucheEmail author K.?Eduard?Linsenmair Heike?Pr?hl 《Behavioral ecology and sociobiology》2012,66(4):613-621
In many species male reproductive success is limited by access to females. Territoriality is one behavioural strategy which
helps to acquire females. In the present study, we investigated the correlation between territory size and (1) female availability
and (2) rate of intrusion by conspecific males in strawberry poison frogs, Oophaga pumilio. Males defended smaller territories in areas with a high female density and high rate of intrusion by conspecific males.
Only males with high body condition values were able to establish territories in areas of high female density probably due
to better fighting abilities. Moreover, dominant calling frequency was lower during agonistic interactions. Because only males
with high body condition values were able to produce very low dominant frequencies, the acoustic properties appear to be an
honest signal containing information about fighting abilities. Thus, the negative correlation between dominant frequency and
mating success of males found in previous studies seems to be in part the result of intrasexual competition between males. 相似文献
24.
Edoardo Mazza Miguel Parra-Saavedra Michael Bajka Eduard Gratacos Kypros Nicolaides Jan Deprest 《黑龙江环境通报》2014,34(1):33-41
Measuring the stiffness of the cervix might be useful in the prediction of preterm delivery or successful induction of labor. For that purpose, a variety of methods for quantitative determination of physical properties of the pregnant cervix have been developed. Herein, we review studies on the clinical application of these new techniques. They are based on the quantification of mechanical, optical, or electrical properties associated with increased hydration and loss of organization in collagen structure. Quasi-static elastography determines relative values of stiffness; hence, it can identify differences in deformability. Quasi-static elastography unfortunately cannot quantify in absolute terms the stiffness of the cervix. Also, the current clinical studies did not demonstrate the ability to predict the time point of delivery. In contrast, measurement of maximum deformability of the cervix (e.g. quantified with the cervical consistency index) provided meaningful results, showing an increase in compliance with gestational age. These findings are consistent with aspiration measurements on the pregnant ectocervix, indicating a progressive decrease of stiffness along gestation. Cervical consistency index and aspiration measurements therefore represent promising techniques for quantitative assessment of the biomechanical properties of the cervix. © 2013 John Wiley & Sons, Ltd. 相似文献
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David D. Cohen Jagoda Crawford Eduard Stelcer Vuong Thu Bac 《Atmospheric environment (Oxford, England : 1994)》2010,44(31):3761-3769
Fine particulate matter (PM2.5), source fingerprints and their contributions have been measured and reported previously at Hanoi, Vietnam, from 25 April 2001 to 31 December 2008. In this study back trajectories are used to identify long range transport into Hanoi for two of these sources, namely, windblown dust (Soil) from 12 major deserts in China and emissions from 33 coal fired power plants (Coal) in Vietnam and China. There were 28 days of extreme Soil events with concentrations greater than 6 μg m?3 and 25 days of extreme Coal with concentrations greater than 30 μg m?3 from a total of 748 sampling days during the study period. Through the use of back trajectories it was found that long range transport of soil from the Taklamakan and Gobi desert regions (more than 3000 km to the north west) accounted for 76% of the extreme events for Soil. The three local Vietnamese power stations contributed to 15% of the extreme Coal events, while four Chinese power stations between 300 km and 1700 km to the north-east of Hanoi contributed 50% of the total extreme Coal events measured at the Hanoi sampling site. 相似文献
28.
Feichtinger Franz Smidt Stefan Klaghofer Eduard 《Environmental science and pollution research international》2002,9(2):31-36
The water balance for the site Mühleggerköpfl in the North Tyrolean Limestone Alps has been established to a soil depth of 50 cm. The evaporation amounts to 42% and deep percolation is 58 % of the precipitation. The surface runoff was negligible and therefore the according nitrate fluxes as well. Soil water analysis revealed mean nitrate concentrations of 3 to 15 mg NO3 L−1, depending on soil depth. The nitrate concentrations at 50 cm soil depth and the associated percolation rates led to NO2 −N outputs of 15.9 kg NO3 −N ha−1 in the year 1999 and 7.9 kg NO3 ∼N ha−1 in the year 2000.
相似文献29.
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Martin?HeilEmail author Birgit?Baumann Ralf?Krüger K. Eduard?Linsenmair 《Chemoecology》2004,14(1):45-52
Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive
indirect defence mechanism. These plants often produce cellular food bodies (FBs) to
nourish their resident ants. Lipids, proteins, and even highly specialised compounds
such as glycogen have been reported from FBs, but detailed chemical analyses of FB
composition have so far been presented only for Southeast Asian Macaranga
and Central American Piper myrmecophytes. Here we
report the chemical composition of FBs of five myrmecophytic Acacia
(Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS
(lipids). Feeding experiments revealed no hints on any use of external food sources
by the inhabiting Pseudomyrmex ants. These ants
obviously rely completely on FBs and extrafloral nectar provided by their hosts.
The total content of nutrients in Acacia FBs was 15-25% of FB
dry mass, being much lower than in Macaranga or
Piper FBs. Proteins were dominating (8-14 % dm)
in Acacia FBs and thus were present in higher amounts than in
Macaranga FBs, yet in lower amounts than in
Piper. Lipids contributed 1-9 %
of dry mass, showing a lower proportion than in FBs of Macaranga
or Piper. Carbohydrates made up 3-11 % dm, reaching
in most Acacia species the same range as observed in
Macaranga and in Piper FBs.
Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up
a much higher proportion in Acacia FBs than in
Macaranga or Piper
FBs. Both characters might represent an adaptation to producing FBs unprotected at
the leaf tips under dry conditions. Acacia FBs
contain all amino acids and all fatty acids that are considered essential for
insects, and their contents of lipids and proteins are higher than in the leaves
from which they are ontogenetically derived. This indicates a putatively adaptive
enrichment of nutritionally valuable compounds in structures functioning as ant-food. 相似文献