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91.
Light-based archival tags are increasingly being used on free-ranging marine vertebrates to study their movements using geolocation estimates. These methods use algorithms that incorporate threshold light techniques to determine longitude and latitude. More recently, researchers have begun using sea surface temperature (SST) to determine latitude in temperate regions. The accuracy and application of these algorithms have not been validated on free-ranging birds. Errors in both geolocation methods were quantified by double-tagging Laysan (Phoebastria immutabilis Rothschild) and black-footed (P. nigripes Audubon) albatrosses with both leg-mounted archival tags that measured SST and ambient light, and satellite transmitters. Laysan albatrosses were captured and released from breeding colonies on Tern Island, northwestern Hawaiian Islands (23°52N, 166°17W) and Guadalupe Island, Mexico (28°31N, 118°10W) and black-footed albatrosses from Tern Island. Studies were carried out between December 2002 and March 2003. For all birds combined, the mean ± SD great circle (GC) distance between light-based locations and satellite-derived locations was 400±298 km (n=131). Errors in geolocation positions were reduced to 202±171 km (n=154) when light-based longitude and SST-based latitude (i.e. SST/light) were used to establish locations. The SST/light method produced comparable results for two Laysan albatross populations that traveled within distinctly different oceanic regions (open ocean vs more coastal) whereas light-based methods produced greater errors in the coastal population. Archival tags deployed on black-footed albatrosses returned a significantly higher proportion of lower-quality locations, which was attributed to interference of the light sensor on the tag. Overall, the results demonstrate that combining measures of light-based longitude and SST-based latitude significantly reduces the error in location estimates for albatrosses and can provide valid latitude estimates during the equinoxes, when light-based latitude measurements are indeterminate.Communicated by J.P. Grassle, New Brunswick  相似文献   
92.
This paper presents initial investigations of a new approach to monitor ecosystem processes in complex terrain on large scales. Metabolic processes in mountainous ecosystems are poorly represented in current ecosystem monitoring campaigns because the methods used for monitoring metabolism at the ecosystem scale (e.g., eddy covariance) require flat study sites. Our goal was to investigate the potential for using nocturnal down-valley winds (cold air drainage) for monitoring ecosystem processes in mountainous terrain from two perspectives: measurements of the isotopic composition of ecosystem-respired CO2 (delta13C(ER)) and estimates of fluxes of CO2 transported in the drainage flow. To test if this approach is plausible, we monitored the wind patterns, CO2 concentrations, and the carbon isotopic composition of the air as it exited the base of a young (approximately 40 yr-old) and an old (>450 yr-old) steeply sided Douglas-fir watershed. Nocturnal cold air drainage within these watersheds was strong, deep, and occurred on more than 80% of summer nights. The depth of cold air drainage rapidly increased to tower height or greater when the net radiation at the top of the tower approached zero. The carbon isotope composition of CO2 in the drainage system holds promise as an indicator of variation in basin-scale physiological processes. Although there was little vertical variation in CO2 concentration at any point in time, we found that the range of CO2 concentration over a single evening was sufficient to estimate delta 13C(ER) from Keeling plot analyses. The seasonal variation in delta 13C(ER) followed expected trends: during the summer dry season delta 13C(ER) became less negative (more enriched in 13C), but once rain returned in the fall, delta 13C(ER) decreased. However, we found no correlation between recent weather (e.g., vapor pressure deficit) and delta 13C(ER) either concurrently or with up to a one-week lag. Preliminary estimates suggest that the nocturnal CO2 flux advecting past the 28-m tower is a rather small fraction (<20%) of the watershed-scale respiration. This study demonstrates that monitoring the isotopic composition and CO2 concentration of cold air drainage at the base of a watershed provides a new tool for quantifying ecosystem metabolism in mountainous ecosystems on the basin scale.  相似文献   
93.
Summary Chemical analysis of each individual leaf of fivePlantago lanceolata (Plantaginaceae) plants showed that iridoid glycoside content increased from undetectable in the oldest photosynthetic leaves to over 9% dry weight in the youngest leaves. The relative proportion of the two iridoid glycosides inP. lanceolata also changed with leaf age: older leaves had significantly more aucubin, whereas the youngest leaves had primarily or solely catalpol. Oviposition tests with femaleJunonia coenia (Nymphalidae) butterflies, showed that they laid most of their eggs on new leaves.  相似文献   
94.
In men, the length ratio of the second to fourth finger (2D:4D) is smaller, while the length of the fourth finger relative to body height (4D:H) is larger than in women. Inter- and intrasexual variations in 2D:4D and 4D:H may depend on variation in fetal androgen and oestrogen environment. As maternal physiology varies with parity and is differentially affected by gestation of either sex, offspring 2D:4D and 4D:H may change according to sex and number of older siblings and may predict subsequent maternal performance. We analysed 2D:4D and 4D:H in Caucasian university students. 2D:4D was smaller and 4D:H was larger in males than in females, but no sexual dimorphism existed in 2D:H. In males, length ratios did not vary with birth order. 2D:4D became more masculine with increasing proportion of males among older siblings, and 2D:4D and 4D:H became more feminine as the number of older sisters increased. In females, length ratios did not vary with the number of older sisters or brothers. 2D:4D was also not related to birth order, but 4D:H became more masculine with birth order. In females, residual maternal fecundity (number of maternal offspring after the participant) decreased as 4D:H became more masculine. These findings are partly consistent with those from previous studies and suggest that maternal fecundity co-varies with length ratios and thus possibly fetal hormone environment of older offspring. 2D:4D and 4D:H may therefore represent powerful tools to investigate the relationships between fetal environment, offspring phenotype and maternal life history at mechanistic and evolutionary levels.  相似文献   
95.
Embryos of the Japanese medaka (Oryzias latipes) were exposed to serial concentrations of atrazine (0, 25, 50, and 100 ppm) and arsenic trioxide (0, 0.025, 0.05, 0.1 ppm) until hatching. Stasis of circulation, blood islands, titanic convulsions, tube heart and mortality were observed in atrazine-treated embryos. Each endpoint exhibited a concentration-response relationship. Only 4% of the embryos hatched in the 25 ppm, and none in the 50 and 100 ppm, probably due to cell death attributed to the embryos' inability to break from the chorion. With arsenic exposure, hatching was inversely correlated to chemical concentration: 86%, 75% and 54% for 0.025, 0.05 and 0.1 ppm, respectively. Hatching periods were also reduced from 7-13 days in controls to 7-11 days in arsenic-treated embryos. This observation was more pronounced with the 0.05 ppm concentration, showing a reduction of about 4 days. Despite this shortage in hatching time, there were no observable morphological abnormalities, as seen with atrazine. The ecological significance of these findings and implications for the development of sublethal toxicity tests using Japanese medaka embryos are important.  相似文献   
96.
Emission rates for fine particle (<2.5 microm) mass (PM2.5), carbon (organic/elemental), inorganic ions (SO4(2-), NO3-, NH4+), elements (primarily metals), and speciated organic compounds are reported for charbroiling hamburger, steak, and chicken. The PM2.5 rates for charbroiling meats ranged from 4.4 to 11.6 g/kg of uncooked meat in this study. No mass-emission rates are available from grilling, but the speciated organic data are available for these samples. Emission rates varied by type of appliance, meat, meat-fat content, and cooking conditions. High-fat hamburger cooked on an underfired charbroiler emitted the highest amount of PM2.5. The emissions were almost exclusively composed of organic carbon, with small amounts of elements and inorganic ions. Water-soluble K+ and Cl-, which are used as indicators of wood smoke in source apportionment studies, were also present in meat-cooking emissions. The speciated organic compounds that were measured include polycyclic aromatic hydrocarbons (PAHs), cholesterol, and the long-chain gamma-lactones. Charbroiling emissions yielded an average of approximately 3-5 times more PAHs, approximately 20 times more cholesterol, and approximately 10 times more lactones than grilling. These data were utilized in the ambient source apportionment analysis for the 1997 Northern Front Range Air Quality Study source apportionment.  相似文献   
97.
It has been shown that lead (Pb) is able to induce lipid peroxidation, one of the main manifestations of oxidative stress. In this study we examined the relationship between chronic Pb exposure and level of reactive oxygen species (ROS) in reproductive system tissues of sexually mature male Wistar rats. One group of animals (control, K) was allowed to drink distilled water, the second group (Pb) was allowed to drink freely 1% aqueous solution of lead acetate. Another groups had a following supplements: rats were allowed to drink distilled water containing vitamin C (vit C) at concentration of 500 mg/l or Trolox (a vitamin E analog) at concentration of 48 mg/l or vit C (500 mg/l) + Trolox (48 mg/l). The similar groups among Pb-treated animals were examined after treatment with the same vitamins and using the same vitamin doses, dissolved in 1% aqueous solution of lead acetate. In all cases the time of drinking was 6 months. It was found that lead content in samples of tissues from testis, epididymis and in a whole blood in Pb- and Pb with antioxidants treated rats was significantly elevated. Chemiluminescence (CL) emitted by the Pb-treated tissues was significantly higher when compared to the light emission by tissues isolated from the animals of control group. The increase in the CL caused by lead occurs in the following increasing order within the studied tissues: cauda of epididymis < testis < caput of epididymis (19%, 39% and 51%, respectively). Dietary vit C supplementation to the Pb-treated rats for 6 months period decreased the CL from caput of epididymis, cauda of epididymis and testis (by 43%, 24%, 39%, respectively) more effectively in comparison to the control group (35%, 17%, 33%, respectively). Also stronger quenching effect on the light emission from the above mentioned tissues after Trolox supplementation was observed in the Pb-treated group (42%, 21%, 35%, respectively) than in the control group (23%, 13%, 13% respectively). The combination of both antioxidants treatments (vit C and Trolox) did not give a higher significant quenching effect compared to the treatment with the vitamins separately. No ultrastructural changes were found in the seminiferous epithelium of Pb-treated animals. However, we found abnormalities in ultrastructure of epididymal epithelial cells and epididymal spermatozoa in rats of Pb-treated groups. These findings provide ex vivo evidence that Pb causes oxidative cellular damage in reproductive system tissues of adult male rats, which may be closely associated with the ROS production.  相似文献   
98.
Emission samples for toxicity testing and detailed chemical characterization were collected from a variety of gasoline- and diesel-fueled in-use vehicles operated on the Unified Driving Cycle on a chassis dynamometer. Gasoline vehicles included normal particle mass (particulate matter [PM]) emitters (tested at 72 and 30 degrees F), "black" and "white" smokers, and a new-technology vehicle (tested at 72 degrees F). Diesel vehicles included current-technology vehicles (tested at 72 and 30 degrees F) and a high PM emitter. Total PM emission rates ranged from below 3 mg/mi up to more than 700 mg/mi for the white smoker gasoline vehicle. Emission rates of organic and elemental carbon (OC/EC), elements (metals and associated analytes), ions, and a variety of particulate and semi-volatile organic compounds (polycyclic aromatic hydrocarbons [PAH], nitro-PAH, oxy-PAH, hopanes, and steranes) are reported for these vehicles. Speciated organic analysis also was conducted on the fuels and lube oils obtained from these vehicles after the emissions testing. The compositions of emissions were highly dependent on the fuel type (gasoline vs. diesel), the state of vehicle maintenance (low, average, or high emitters; white or black smokers), and ambient conditions (i.e., temperature) of the vehicles. Fuel and oil analyses from these vehicles showed that oil served as a repository for combustion byproducts (e.g., PAH), and oil-burning gasoline vehicles emitted PAH in higher concentrations than did other vehicles. These PAH emissions matched the PAH compositions observed in oil.  相似文献   
99.
An international inter-laboratory research program investigated the effectiveness of in situ remediation of soils contaminated by cadmium, lead and zinc, measuring changes in soil and soil solution chemistry, plants and soil microbiota. A common soil, from mine wastes in Jasper County MO, was used. The soil was pH 5.9, had low organic matter (1.2 g kg(-1) C) and total Cd, Pb, and Zn concentrations of 92, 5022, and 18 532 mg kg(-1), respectively. Amendments included lime, phosphorus (P), red mud (RM), cyclonic ashes (CA), biosolids (BIO), and water treatment residuals (WTR). Both soil solution and NH4NO3 extractable metals were decreased by all treatments. Phytotoxicity of metals was reduced, with plants grown in P treatments having the highest yields and lowest metal concentration (0.5, 7.2 and 406 mg kg(-1) Cd, Pb, and Zn). Response of soil micro-organisms was similar to plant responses. Phosphorus addition reduced the physiologically based extraction test Pb from 84% of total Pb extracted in the untreated soil to 34.1%.  相似文献   
100.
Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils di erently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.  相似文献   
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