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91.
秦松  林光恒 《海洋科学》1991,15(6):52-56
为了探究化学诱变剂镉在海洋食物链中的传递规律及其与人类健康的关系,作者设计了从海洋浮游藻类——褐指藻(Phaeodactylum tricornutum Bohlin)~海湾扇贝(Argopecten irradians Lamarck)的实验室食物链,采用极谱分析方法研究了镉的传递,并对贝肉(软体组织)灰样进行了紫露草微核(Trad-MCN)测定,结果:(1)经过6d的传递实验,处理组与对照组贝肉中镉的浓度均未超过对应组褐指藻中镉的浓度;经过这条食物链的传递,镉的浓度减少。(2)通过t测验发现,两个高浓度处理组与对照组贝肉灰样之间的诱变性差异显著(P<0.001与P<0.005)。t值的大小与镉的浓度具有一致性关系,说明镉的浓度越大,诱变性越强。  相似文献   
92.
Desorption and bioaccumulation of Cd, Zn, and Pb were studied using naturally contaminated sediment from a brackish water pond in the Sunderban Biosphere Reserve in India. Pattern of desorption of the metals from the sediment and bioaccumulation in fingerlings of the teleost Oreochromis mossambicusand postlarvae of the shrimp Penaeus monodon were studied as a function of salinity and loading of detritus of a mangrove plant. Effects of both salinity and loading of detritus on bioaccumulation of the metals were studied under two conditions: either the animals were allowed free access to the sediment or access was denied. Ninety‐six hour experiments showed that desorption of Cd and Pb from sediment into water increased with salinity of the medium while desorption of Zn decreased. Salinity of the medium also had a significant effect on the bioaccumulation of metals by fish; Cd and Pb accumulation decreased in saline medium while the accumulation of Zn increased. Conditions of access to sediment had no effect on the bioaccumulation of metals by fish; effect of interaction between salinity and access condition was also insignificant. The access conditions, however, significantly influenced accumulation of metal by the shrimp postlarvae. The effect of interaction between salinity and access condition was insignificant in influencing the bioaccumulation of all metals except Zn. The accumulation of Zn increased as a function of the salinity of the medium when shrimp postlarvae were allowed access to the sediment. Desorption of metals from sediment to water were below detection limits when detritus of a mangrove plant was added to the medium. Both the level of detritus and the conditions of access influenced accumulation of metals by fish, but the effect of interaction between the two factors were found to be insignificant. Shrimp postlarvae showed net accumulation only of Pb in the presence of detritus and the accumulation of Pb increased when the larvae were separated from the sediment. The results are important in understanding the mobility of metals between solid and aqueous phases in brackish water environments that experience periodic fluctuations in salinity and fluxes of organic load in the form of mangrove detritus.  相似文献   
93.
The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals.  相似文献   
94.
We analyzed Hg, Zn and Cu concentrations in the liver and muscle of tiger sharks (Galeocerdo cuvier) from the coast of Ishigaki Island, Japan. The Hg concentration in the muscle increased proportionally with body length in the tiger sharks, whereas that in the liver increased rapidly after maturity (defined by a length of over 2.7 m). Muscle Hg levels were higher than liver concentrations in immature sharks, with the inverse trend observed in mature sharks. Notably, the Zn and Cu concentrations in the liver tended to decrease with increasing body length. This rapid increase in hepatic Hg concentration concurrent with the onset of maturity in sharks may result from the continuous intake of Hg via food and the slower growth of mature sharks. The high concentrations of the essential metals Zn and Cu in immature sharks may be explained by the physiological demands related to rapid growth.  相似文献   
95.
The glassfish, Ambassis jacksoniensis, is a key, mid-level species in an estuarine food web on the east coast of Australia. Estuaries are subject to contamination from urban and industrial activities. The biokinetics of Cd, Se and Zn accumulation by glassfish from water and food were assessed using radioisotopes. Metal uptake from water was not regulated over the range of water metal concentrations examined. Metal uptake from food was assessed using brine shrimp (Artemia sp.) fed radio-labelled algae. The assimilation efficiency from food was 9.5 ± 2.5%, 23 ± 2.2% and 4.6 ± 0.6% for Cd, Se and Zn, respectively. The potential for biomagnification was low for all metals. Food is the main metal uptake pathway for glassfish, with 97%, 99% and 98% of the uptake of Cd, Se and Zn, respectively, estimated to be from food.  相似文献   
96.
The manufacturing of phosphoric acid from natural calcium phosphate generates a solid residue containing 25–30% humidity. This solid residue (phosphogypsum) generates acidic solution (pH ≈ 2.5) containing several toxic ionic species, that coat its grains. Fluorides and heavy metals such as cadmium are considered the most harmful species contained in the released solution from phosphogypsum. The purpose of this work is to study the trapping of fluorides and cadmium in phosphogypsum as well as effluent neutralization before its discharge into natural recipient. Therefore, calcium carbonate finely ground was added and fully mixed with wet phosphogypsum. A four factors central composite design was used to model and to optimize the operating parameters that govern the process. The studied factors were temperature, reaction time, mass, and grains size of CaCO3. Considered responses were pH, F, and Cd2+ concentrations in the released solution after reaction with CaCO3. The optimum operating conditions were quite efficient to trap, respectively, 99% Cd2+ and 97% of F with a final pH of 6.66. So an original, easy, simple, and cost effective method to trap some toxic species on phosphogypsum through CaCO3 addition would likely to be integrated in phosphoric acid manufacturing plant.  相似文献   
97.
This study was undertaken to determine the cadmium removal efficiency of Lemna minor when it was used for treatment of wastewater having different characteristics, i. e., pH, temperature and cadmium concentration. Plants were cultivated in different pH solutions (4.5–8.0) and temperatures (15–35°C) in the presence of cadmium (0.1–10.0 mg/L) for 168 h. The amount of biomass obtained in the study period, the concentrations of cadmium in the tissues and in the media and net uptake of cadmium by Lemna have been determined for each condition. The percentages of cadmium uptake (PMU) and bioconcentration factors (BCF) were also calculated. The highest accumulation was obtained for the highest cadmium concentration of 10.0 mg Cd/L as 11.668 mg Cd/g at pH 6.0, and as 38.650 mg Cd/g at 35°C and pH 5.0. The cadmium accumulation gradually increased with initial concentration of the medium, but the opposite trend was observed for the PMU. However, the maximum PMU was obtained as 52.2% in the solution with the lowest concentration of 0.1 mg Cd/L. A mathematical model was used to describe the cadmium uptake and the equation obtained was seen to fit the experimental data very well.  相似文献   
98.
Metal concentrations measured in the organs of beached whales are published regularly. Few of these, however, describe metal levels in nursing females. In the present study, mercury, lead, copper and zinc levels were measured in the milk and tissues of a female Bottlenose dolphin. Results reveal that metal pollutants pass from the tissue into the milk.  相似文献   
99.
In 1982, sediments contaminated with zinc, cadmium, and copper were dredged from Lake DePue in Illinois and deposited in a diked sediment disposal area (DSDA) that is flooded annually for at least three months. Data from soil and groundwater samples collected at multiple depths within and adjacent to the DSDA indicate vertical movement of the metals in the subsurface, although groundwater outside of the DSDA was not contaminated with any of the metals. Zinc was elevated in almost all of the wells inside the DSDA. Cadmium concentrations were elevated in shallow wells inside the DSDA, while copper was rarely detected in the groundwater. Comparisons of groundwater samples taken within the DSDA under flooded and unflooded conditions suggest that pH and redox conditions controlled metal solubilities. A comparison between soil cores and sediment cores from Lake DePue suggest that zinc was more mobile than cadmium or copper within the DSDA.  相似文献   
100.
阐述了镉(Cd)的生物危害性与水分运移、水量变化和作物含水量之间的内在联系,揭示了镉的生物毒性危害与水分变化作用的机制,这对于治理镉污染土地、减轻和控制其生物毒性危害作用具有重要意义。  相似文献   
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