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261.
大同盆地砷、氟中毒地方病生态地球化学研究 总被引:16,自引:1,他引:16
山西大同盆地属干冷荒漠景观条件的半封闭型断陷盆地。区内有害元素的聚集导致氟中毒等多种地方病肆虐,20世纪90年代因开发和饮用深层地下水爆发了水砷中毒病。经地球化学调查发现:地下潜水高含F,超标1.3~12倍;深层承压地下水富As,砷含量超标2~20倍。砷中毒发病率与饮水中As3+/∑As比值呈正相关关系。盆地周边分布多层富含As和F的地层和火成岩体,处于富As、F的区域地球化学省内。由于大同盆地的不均匀沉降,在其边缘部分形成深凹陷带,含砷下渗地下水经有机碳质层的还原作用,使砷还原为三价,提高了地下水的毒性并滞留聚集。探讨了F、As富集和中毒的机理和生态地球化学危害评价,提出了治理和外围调查预测建议。 相似文献
262.
Nendza M 《Marine pollution bulletin》2007,54(8):1190-1196
Non-eroding silicone-based coatings can effectively reduce fouling of ship hulls and are an alternative to biocidal and heavy metal-based antifoulings. The products, whose formulations and make up are closely guarded proprietary knowledge, consist of a silicone resin matrix and may contain unbound silicone oils (1-10%). If these oils leach out, they can have impacts on marine environments: PDMS are persistent, adsorb to suspended particulate matter and may settle into sediment. If oil films build up on sediments, infiltration may inhibit pore water exchange. PDMS do not bioaccumulate in marine organisms and soluble fractions have low toxicity to aquatic and benthic organisms. At higher exposures, undissolved silicone oil films or droplets can cause physical-mechanic effects with trapping and suffocation of organisms. These 'new' effects are not covered by current assessment schemes. PDMS make the case that very low water solubility and bioavailability do not necessarily preclude damage to marine environments. 相似文献
263.
氨氮对我国不同产地卤虫的急性毒性试验 总被引:1,自引:0,他引:1
采用静水生物试验法测定了NH3-N对我国新疆艾比湖(AB),青海柯柯湖(KK),海南莺歌海(YGH),山东埕口(CK)产地卤虫的初孵无节幼虫,拟成虫及成体的急性毒性试验。结果表明:1.不同发育阶段的卤虫对氨氮的耐受力是:成虫>初孵无节幼虫>拟成虫>。2.不同产地卤虫对氨氮的耐受力有一定的差异,AB、KK、CK产地的卤虫对氨氮的耐受力均高于YGH产卤虫。 相似文献
264.
Tests for the acute toxicity of tributyltin (TBT) were conducted on amphipod crustaceans collected from Otsuchi Bay, Japan. Five species of caprellids and three species of gammarids, which belong to a closely related ecological niche, were used for the exposure experiments at seven test concentrations (0, 0.001, 0.01, 0.1, 1, 10 and 100 microg TBTCl/l) for 48 h at 20 degrees C. The 48-h LC50 values of the caprellids were 1.2-6.6 microg TBTCl/l, and these were significantly lower than those of the gammarids (17.8-23.1 microg TBTCl/l). This suggests that caprellids are more sensitive to TBT than gammarids. Furthermore, the proportions of TBT and its derivatives, dibutyltin (DBT) and monobutyltin (MBT), were measured in the amphipods collected from Otsuchi Bay. In the caprellids, TBT was the predominant compound, accounting for 72% of the total butyltin which reflected the butyltin ratio in seawater, while in the gammarids, TBT's breakdown products (DBT and MBT) predominated, accounting for 75% of the total butyltin. This difference suggests that caprellids may have lower metabolic capacity to degrade TBT than gammarids. Therefore, the difference in sensitivity to TBT among the amphipods is thought to be related to the species-specific capacity to metabolize TBT. 相似文献
265.
266.
目的:探讨急性胰腺炎的16层螺旋CT诊断分级方法及临床意义。方法:回顾性分析2009~2011年间急性胰腺炎住院患者41例,其中男23例,女18例。所有患者均作CT平扫和增强扫描。结果:按照CT严重指数分级评分:根据得分将结果依次分为3个等级:轻级(0~3分)23例,占56.1%,中级(4~6分)7例,占17.1%,重级(7~10分)11例,占26.8%。结论:螺旋CT为急性胰腺炎的诊断提供了直观的形态学依据,CTSI不仅能精确反映急性胰腺炎的病变程度,而且能较准确早期判断急性胰腺炎病情、预后,并对其临床治疗方案及预后具有重要意义。 相似文献
267.
Series of experiments, including background sediment elutriate, spiked-sediment elutriate and spiked- water toxicity tests, were carried out to study the effect of dredging on survivability and ecological competence of commercially important shrimp postlarvae of Penaeus monodon Fabricius. The test sediment represented the most contaminated from endosulfan and lindane in the Chantaburi river mouth estuary. The maximum sediment contamination levels were 49.4 μg/kg of endosulfan and 58.1 μg/kg of lindane in dry weight basis. Dose-response studies in static, non-renewal spiked-sediment elutriate toxicity tests revealed that LC 50 (96 h) values for survival effect based on measured concentrations were 0.50 (0.26-0.95) μg/L for endosulfan and 0.92 (0.63-1.34) μg/L for lindane. The LOECs for endosulfan and lindane were 0.141 and 0.429 μg/L, respectively. The NOECs were estimated to be the dissoluted endosulfan and lindane concentrations from the Chantaburi estuary sediment. The effects on phenoloxidase enzyme activity in shrimp postlarvae exposed for sub-lethal to lethal doses in sediment elutriate were not significant (p〉0.05) at all tested dose levels. The worst case dissolution concentrations of endosulfan and lindane in the water column upon simulatory dredging in the Chantaburi estuary were found to be toxic to shrimp postlarvae on lethal and sub-lethal effects. The NOECs of respective chemicals (i.e., 0.034 and 0.16 μg/L) shared the same orders of magnitude for corresponding NOECs established for whole salt water aquatic life by the USEPA and "safe" levels calculated by 0.01 safety factor approach. In addition, the significance of multiple pollutant assessments for ecological toxicity testing is highlighted. 相似文献
268.
重金属对几种海洋双壳类和甲壳类生物的毒性 总被引:13,自引:2,他引:13
研究了重金属和污染疏浚物对缢蛏Sinonuacula constricta稚贝和幼贝,褶牡蛎Ostrea plicatula幼虫,甲壳类的卤虫Artemiasp.幼体和长毛对虾Penaeuspencillatus幼体的毒性,结果表明受试生物的生长,摄食,存活均受到不同程度的影响。各重金属元素对褶牡蛎幼虫,卤虫无节细,长毛对虾糖虾期的毒性顺序为Hg^2^+>Cu^2^+>Zn^2^+>Cd^2^+> 相似文献
269.
中国海域四株亚历山大藻的毒素分析 总被引:4,自引:0,他引:4
利用高效液相色谱法对4株采自中国不同海域的亚历山大藻所含有的麻痹性贝类毒素(PSP)进行了分析。结果显示,Alexandriumcatenella(东海株)的主要毒素成分为C2毒素,占其所含毒素总量的88.39%,细胞毒性大小为1.08pgSTX·eq/cell,毒力较低;Alexandriumtamarense(东海株)的毒素组成与A.catenella(东海株)的基本相同,但多含了一种膝沟藻毒素(GTX4),含毒量也比较低,细胞毒性大小为1.58pgSTX·eq/cell;Alexandriumminutum(台湾株)只检测出4种膝沟藻毒素(GTX1,2,3,4),其中GTX2,3摩尔百分比占到总量的75.42%,细胞毒性大小为21.32pgSTX·eq/cell;Alexandriumtamarense(南海株)毒素成分有9种,其中GTX4,6占据主要成分,占其所含毒素总量的54.92%,细胞毒性大小为5.01pgSTX·eq/cell。 相似文献
270.
Industrial effluents are one of the main pollutants leading to marine pollution, especially in the littorals with highly dense population and developed industries[1]. Dyeing, electroplating and pesticide effluents are all common industrial effluents, liable to enter inshore sea area. Generally, the supervision of effluents could be carried out through chemical analysis. The determined results, however, cannot directly reflect the effects of effluents on aquatic organisms. In this respect, bioa… 相似文献