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731.
Kazuharu Ohashi Daniel D’Souza James D. Thomson 《Behavioral ecology and sociobiology》2010,64(5):891-897
Nectar-feeding animals have served as the subjects of many experimental studies and theoretical models of foraging. Their
willingness to visit artificial feeders renders many species amenable to controlled experiments using mechanical “flowers”
that replenish nectar automatically. However, the structural complexity of such feeders and the lack of a device for tracking
the movements of multiple individuals have limited our ability to ask some specific questions related to natural foraging
contexts, especially in competitive situations. To overcome such difficulties, we developed an experimental system for producing
computer records of multiple foragers harvesting from simple artificial flowers with known rates of nectar secretion, using
radio frequency identification (RFID) tags to identify individual animals. By using infrared detectors (light-emitting diodes
and phototransistors) to activate the RFID readers momentarily when needed, our system prevents the RFID chips from heating
up and disturbing the foraging behavior of focal animals. To demonstrate these advantages, we performed a preliminary experiment
with a captive colony of bumble bees, Bombus impatiens. In the experiment, two bees were tagged with RFID chips (2.5 × 2.5 mm, manufactured by Hitachi-Maxell, Ltd., Tokyo, Japan)
and allowed to forage on 16 artificial flowers arranged in a big flight cage. Using the resulting data set, we present details
of how the bees increased their travel speed between flowers, while decreasing the average nectar crop per flower, as they
gained experience. Our system provides a powerful tool to track the movement patterns, reward history, and long-term foraging
performance of individual foragers at large spatial scales. 相似文献
732.
A. A. Nikol’skii 《Russian Journal of Ecology》2008,39(7):530-536
With consideration of the data on soil temperature within the range of the Altai zokor Myospalax myospalax Laxmann (1773) published in the Handbook on the Climate of the Soviet Union, it has been shown that the actual temperature niche of this species is relatively narrow. Seasonal movements over the vertical
profile of the burrow allow zokors to avoid exposure to subzero temperatures. 相似文献
733.
Energy expenditures for reproduction in local populations of the pied flycatcher in the environs of the Middle Urals Copper Smelter (Revda, Sverdlovsk oblast) have been estimated on the basis of the results of long-term studies (1989?C2008). It is shown that the total energy expenditures per fledgling over the nesting period are 1.2 times higher than in the background area, which is explained by increased energy losses (by a factor of 4.1) resulting from partial mortality of the progeny (eggs or nestlings). Variation in the average energy ??cost?? of one fledgling in the heavily polluted zone is also higher, compared to the background area. Average energy expenditures per fledgling increase in years with cold weather, and the same is observed when the birds lay larger clutches. 相似文献
734.
Srinivasa Jayachandra Urban Ja D’Souza 《Journal of environmental science and health. Part. B》2013,48(4):271-278
The objective of this research is to study the possible reproductive adverse effects of diazinon on rat offspring exposed in utero and during lactation. Twenty-four Sprague–Dawley female rats (10–12 week old) were randomly assigned to four groups, each consisting of six rats. Group 1 served as the control and these rats were given normal saline orally. Rats in groups 2, 3, and 4 were administered diazinon, dissolved in saline at 10, 15, 30 mg/ kg?1 body weight, per oral, once daily, during mating, pregnancy and lactation. The male offsprings were examined at puberty and adulthood for body weight, testis weight, epididymis weight, sperm count, motility and morphology, pituitary-gonadal hormone levels. At 30 mg kg?1 dose, the male offsprings showed a decrease in testicular weight, sperm count, motility, with an increase in abnormal sperm percentage and a decline in pituitary-gonadal hormones, at puberty. Upon attaining adulthood, there was a decrease in testicular weight, sperm count and motility with an increase in abnormal sperm percentage and a decrease in pituitary hormone level. There was evidence of some adverse reproductive effects on the male offspring at the 15 mg/ kg?1 dose. Most of the adverse effects were irreversible and were evident at both puberty and adulthood in the offsprings, although a few parameters reverted to the normal growth pattern. Diazinon is a reproductive toxicant for male offsprings if exposed during prenatal and postnatal phases. 相似文献
735.
Johan Gardères Laure Taupin Jasnizat Bin Sa?din Alain Dufour Ga?l Le Pennec 《Marine Biology》2012,159(8):1685-1692
Many bacteria live in close association with sponges. Within these consortia, molecules of communication such as quorum-sensing and hormone-like molecules may occur in order to regulate the partnership. Of particular interest, bacterial N-acyl-l-homoserine lactones (AHLs) were screened in supernatants from Suberites domuncula-associated bacteria using an E. coli bioluminescent reporter system. These sponge-associated bacteria were beforehand isolated on several media supplemented or not with a sponge extract to attempt to isolate sponge-specific bacteria. Out of 81 AHL-producing bacteria, three strains requiring sponge extract to grow were selected for AHL characterization. The in vitro produced AHLs, that is, in bacterial culture supernatants, were identified as N-(3-butanoyl)-l-homoserine lactone and N-(3-oxododecanoyl)-l-homoserine lactone and quantified using LC–ESI–MS/MS. The in vivo production of AHLs by sponge-associated bacteria has also been demonstrated in a healthy host for the first time: N-(3-oxododecanoyl)-l-homoserine lactone, N-(3-hexanoyl)-l-homoserine lactone, and N-(3-heptanoyl)-l-homoserine lactone. This AHL production in sponges may suggest a potential role of these molecules between sponge-associated bacteria and/or between sponge-associated bacteria and the sponge. 相似文献
736.
Zarza Eugenia Diego-García Elia García Luz Verónica Castro Ricardo Mejía Gamaliel Herrera David Cuevas Raúl Palomeque Ángeles Iša Pavel Guillén Karina 《Food and environmental virology》2022,14(2):199-211
Food and Environmental Virology - The COVID-19 pandemic has been monitored by applying different strategies, including SARS-CoV-2 detection with clinical testing or through wastewater-based... 相似文献
737.
738.
739.
Non-host organisms affect transmission processes in two common trematode parasites of rocky shores 总被引:1,自引:0,他引:1
Katrin Prinz Thomas C. Kelly Ruth M. O’Riordan Sarah C. Culloty 《Marine Biology》2009,156(11):2303-2311
The transmission of free-living trematode stages is mediated by various environmental factors, of which the presence of ambient
organisms within the host space is a potential major determinant. In two laboratory mesocosm experiments, we investigated
the influence of four intertidal rocky shore species on transmission success of cercariae of the digenean trematodes Echinostephilla
patellae (encysting in the tissue of blue mussels Mytilus edulis) and Parorchis
acanthus (encysting on mussel shells). Encystment success of both parasite species was significantly lower in the presence of test
organisms when compared to controls. Observations revealed that barnacles Austrominius
modestus actively filtered cercariae, whereas the larvae were obstructed by the seaweeds Corallina
officinalis and Fucus
serratus. Anemones Actinia
equina both physically disturbed and consumed cercariae. In a further laboratory experiment, grazing gastropods (Littorina
littorea, Patella
vulgata, and Gibbula
umbilicalis) were found to significantly reduce the numbers of P. acanthus metacercariae in artificially prepared dishes by ingestion of cysts. Our results suggest that non-host organisms may play
a key role in regulating the transmission of free-living trematode stages in rocky shore ecosystems, which is especially important
with regard to the relative diversity and density of species in these habitats. The findings also emphasize the need to include
parasites into marine food webs, since cercariae seem to be consumed by certain organisms to a considerable extent and could
possibly represent an important energy source. 相似文献
740.
The spatial distribution of ichthyofauna in water bodies of the northern Polar Urals is reviewed. Four lake types are distinguished
according to the species composition of fishes. The faunistic ranking of water bodies has been performed. The zoogeographic
boundary between the ranges of the European and Siberian ichthyofaunas in the freshwater part of the Arctic has been determined. 相似文献