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61.
62.
In the intertidal limpet Patelloida pygmaea, two distinctive morphs, the forms pygmaea and conulus, have been recorded. The former possesses a flat elongated shell, and the latter has an extremely high round shell. It has been observed in the field that pygmaea is found on oyster shells Crassostrea gigas. The form conulus uses an unusual substrate for attachment. It is found on the living shells of the intertidal gastropod Batillaria cumingi. Although conulus is normally found only on shells of Batillaria, it can also be found on oyster shells when pygmaea and Batillaria shells are not present in nature. An electrophoretic analysis of allozymes showed that these two forms are reproductively isolated from each other and coexist without gene exchange on the same mudflat. Laboratory experiments showed that pygmaea prefers oyster shells and conulus prefers Batillaria shells as substrates for attachment when both oyster and Batillaria shells are present. The form pygmaea did not attach to Batillaria shells, even when only Batillaria shells were available. However, conulus also attached to oyster shells when Batillaria shells were not available. The proportion of individuals of conulus that attached to oyster shells decreased significantly when pygmaea was attaching to the oyster shells. These results suggest that pygmaea is ecologically more specialized to living on oyster shells than conulus. 相似文献
63.
64.
Tomoyoshi?HirotaEmail author Kazuei?Usuki Masaki?Hayashi Manabu?Nemoto Yukiyoshi?Iwata Yosuke?Yanai Tomotsugu?Yazaki Satoshi?Inoue 《Mitigation and Adaptation Strategies for Global Change》2011,16(7):791-802
In the northernmost region of Japan (Hokkaido Island), earlier onsets of thick snowcover in recent years (post 1980) have
reduced the penetration depth of soil frost, resulting in over-winter survival of unharvested small potato (Solanum tuberosum) tubers that emerge as weeds in the spring in rotation crop fields. To prevent the occurrence of potato weeds, a method was
developed to manipulate soil-frost depths by artificially controlling snowcover thickness, guided by a simple numerical model
that simulates soil freezing-thawing processes using daily mean air temperature and snowcover thinckness as input variables.
The method involves removal of snowcover to expose the soil surface in the beginning of winter until the soil freezes to a
sufficient depth. After that time, snow is deposited back or allowed to accumulate naturally to prevent further penetration
of frost, which may cause undesirable delay in the seeding of spring crops. Field trials indicated that the model predicted
frost depths within several centimeters of observed values, when measured temperature and snowcover thickness were used as
model input. Based on the field and laboratory data, a soil temperature of −3°C is necessary for complete elimination of potato
tubers. To achieve this temperature in potato-burial zones without causing excessive freezing, an optimal frost depth is 0.3
to 0.4 m. The method is being adopted by progressive potato producers in the region, who use tractor-mounted snow ploughs
to manipulate snowcover over a large scale. This is an emerging new technology for agricultural adaptation to climate variability. 相似文献
65.
Kameoka Hiroshi Ito Koji Ono Junko Banno Arisa Matsumura Chisato Haga Yuki Endo Kazuto Mizutani Satoshi Yabuki Yoshinori 《Journal of Material Cycles and Waste Management》2022,24(1):287-296
Journal of Material Cycles and Waste Management - Per- and polyfluoroalkyl substances (PFASs) are used in products, such as aqueous film-forming foam and fluorochemical surfactants, because of... 相似文献
66.
Shigeru Kawamata Satoshi Yoshimitsu Shigemitsu Tokunaga Satoshi Kubo Toshihiro Tanaka 《Marine Biology》2012,159(4):723-733
Although sediment deposition has detrimental effects on macroalgal settlement and recruitment, fucoid algae (mainly Sargassum duplicatum) thrive on rocky reefs always overlaid with fine sediments in sheltered sites of Kagoshima, Japan. The aim of the present
study was to assess their ability to settle and recruit onto sediment-covered substrata. A transplant experiment using boulders
with Sargassum juveniles attached showed that the 30-day survival rate was as high as 50% even for the juvenile stage (<10 mm) on boulders
completely buried with sediment. In addition, an outdoor tank experiment testing the effects of different sediment thicknesses
(0–4 mm) on already settled 4-day old S. duplicatum germlings indicated significant reductions in growth by the presence of sediment cover even at 0.5 mm but no significant
increase in mortality up to 2 mm. Furthermore, an in situ experiment in which sterilized cobbles were placed at a sediment-covered
site to allow sediment to settle over them before the embryo release showed a uniformly high recruitment of Sargassum over the cobbles. This suggests the presence of unknown mechanisms to allow the settlement of propagules on substrata thinly
but completely covered by fine sediments. 相似文献
67.
Masako Nakamura Ken Okaji Yoshimi Higa Eiji Yamakawa Satoshi Mitarai 《Marine Biology》2014,161(11):2521-2530
Boom and bust dynamics are a prominent characteristic of the crown-of-thorns starfish (Acanthaster planci) populations. Outbreaking starfish populations damage coral communities extensively and then often disappear quickly. In contrast, Onna village, on the central west coast of Okinawa Island, Japan, has been experiencing chronically high population densities of A. planci for decades. In this study, we examined spatial and temporal population dynamics of A. planci along the coast of Onna village, using removal data gathered over 24 years by a local fisheries cooperative. The results demonstrate that A. planci populations along the Onna coast often experienced high densities prior to 2003 and that recently, populations have again been increasing drastically. Size-frequency distributions suggest multiple, successive recruitment, as one of the driving factors maintaining A. planci populations in this location. Moreover, within the Onna area, the timing of outbreak peaks varied among different locations, showing a northward progression. 相似文献
68.
Aqueous phenol solutions containing TiO(2) nanoparticles were irradiated with ultraviolet (UV), gamma-ray and electron beams. Organic compounds were fully removed by each type of radiation in the presence of the particles. The absorbed energy of the ionizing radiation (gamma-ray and electron beams) needed for removal was much lower than that of UV photocatalysis. Phenol was decomposed by the ionizing radiation in the absence of the nanoparticles and the addition of TiO(2) had no significant effect on phenol decomposition rate. Instead, total organic carbon (TOC) removal using the ionizing radiation was accelerated drastically by TiO(2). It is suggested that TiO(2) particles affect the intermediate compounds produced through the decomposition of phenol. The amount of removed TOC per absorbed energy were compared in the absence and the presence of TiO(2) nanoparticles. Radiolysis with the nanoparticles showed consistently high rate and high efficiency of TOC removal. 相似文献
69.
Molting and breeding entail major energetic costs for female crustaceans. However, females of some hermit crabs perform a
molt immediately prior to copulation (prenuptial molt). The evolutionary significance of the prenuptial molt was examined
in Pagurus hermit crabs, and two hypotheses were tested: (1) prenuptial molt might enhance the success of the present clutch by cleaning
the pleopods of females and thereby preventing eggs from being dislodged from the pleopods, and (2) prenuptial molt might
function for growth and increase future fecundity at the cost of energetic expenditure on the present brood. Although these
hypotheses are not mutually exclusive, our results rejected the former hypothesis and supported the latter hypothesis. All
four Pagurus species examined showed significant negative relationships between prenuptial molting and continuity of breeding; i.e., they
showed high molting frequency after they had a long rest period from breeding. Females of P. minutus increased their size through the prenuptial molt, and showed a decreased clutch size due to the molt. The number of dislodged
eggs increased if females molted in P. minutus. These results suggest that hermit crabs undergoing a prenuptial molt might not gain any clear immediate advantage of enhanced
survival of eggs in the present clutch, and that the prenuptial molt would mainly contribute to growth. 相似文献
70.
DABWAN Ahmed H A IMAI Daizo KANECO Satoshi SENMATSU Isamu NAKAHAMA Katsuyuki KATSUMATA Hideyuki SUZUKI Tohru OHTA Kiyohisa 《环境科学学报(英文版)》2008,20(2):172-176
A sintering technology for preparing porous materials from sea bottom sediments was developed for use in water purification. The purpose of the present study was to develop methods for converting the sea bottom sediments dredged from Ago Bay into value-added recycled products. The sintered products fabricated at 400℃ were found to be very effective adsorbents for the removal of heavy metals. 相似文献