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11.
Protected area delineation and conservation action are urgently needed on marine islands, but the potential biodiversity benefits of these activities can be difficult to assess due to lack of species diversity information for lesser known taxa. We used linear mixed effects modeling and simple spatial analyses to investigate whether conservation activities based on the diversity of well‐known insular taxa (birds and mammals) are likely to also capture the diversity of lesser known taxa (reptiles, amphibians, vascular land plants, ants, land snails, butterflies, and tenebrionid beetles). We assembled total, threatened, and endemic diversity data for both well‐known and lesser known taxa and combined these with physical island biogeography characteristics for 1190 islands from 109 archipelagos. Among physical island biogeography factors, island area was the best indicator of diversity of both well‐known and little‐known taxa. Among taxonomic factors, total mammal species richness was the best indicator of total diversity of lesser known taxa, and the combination of threatened mammal and threatened bird diversity was the best indicator of lesser known endemic richness. The results of other intertaxon diversity comparisons were highly variable, however. Based on our results, we suggest that protecting islands above a certain minimum threshold area may be the most efficient use of conservation resources. For example, using our island database, if the threshold were set at 10 km2 and the smallest 10% of islands greater than this threshold were protected, 119 islands would be protected. The islands would range in size from 10 to 29 km2 and would include 268 lesser known species endemic to a single island, along with 11 bird and mammal species endemic to a single island. Our results suggest that for islands of equivalent size, prioritization based on total or threatened bird and mammal diversity may also capture opportunities to protect lesser known species endemic to islands. Beneficios de los Taxa Poco Estudiados para la Conservación de la Diversidad de Aves y Mamíferos en Islas  相似文献   
12.
在实地调查和数量系统分析的基础上,论述了九岭幕阜山中国种子植物特有属的物各多样性,空间分布格局及其区系地理特征,探讨了本区与邻近地区中国种子植物特有属分布的联系及其重要地位,并对特有属的生物多样性保护提出了具体对策。  相似文献   
13.
Abstract:   The Juan Fernandez Archipelago, a Chilean national park and biosphere reserve, is 700 km west of continental Chile. Invasive plant species pose major threats to the native, highly endemic vegetation, especially on Robinson Crusoe Island (Mas a Tierra), where there is a permanent settlement. We used historical and recent vegetation map data as well as recent vegetational point data to reconstruct vegetational changes on the island since the early twentieth century. In addition, we used logistic regression models with environmental variables or their surrogates (elevation, solar radiation, topographic similarity index, slope position) to estimate the potential distributions of the worst invaders. Native vegetation has been affected most severely by Acaena argentea , Aristotelia chilensis , Rubus ulmifolius , and Ugni molinae , leading to a significant decrease of endemic plants in the montane forests and native shrublands. The native forest has decreased by approximately one-third. The area affected by Aristotelia chilensis increased from 6.5% to 14% of the total island area. Ugni molinae , once rare, is now abundant (4.6%), as is Acaena (11.9%). Rubus ulmifolius , not present 80 years ago, now covers about 7% of the island's surface. The distributions of all studied species except Rubus ulmifolius are significantly ( p < 0.05) controlled by the environmental factors we examined. Inferring from potential distributions of Aristotelia chilensis and Ugni molinae , 50% of the native montane forest could be invaded or replaced (with a probability of >60%) by these plants. Based on the invasion speed of the past 80 years, this would take another 80 years if conservation measures do not succeed.  相似文献   
14.
The giant panda attracts disproportionate conservation resources. How well does this emphasis protect other endemic species? Detailed data on geographical ranges are not available for plants or invertebrates, so we restrict our analyses to 3 vertebrate taxa: birds, mammals, and amphibians. There are gaps in their protection, and we recommend practical actions to fill them. We identified patterns of species richness, then identified which species are endemic to China, and then which, like the panda, live in forests. After refining each species' range by its known elevational range and remaining forest habitats as determined from remote sensing, we identified the top 5% richest areas as the centers of endemism. Southern mountains, especially the eastern Hengduan Mountains, were centers for all 3 taxa. Over 96% of the panda habitat overlapped the endemic centers. Thus, investing in almost any panda habitat will benefit many other endemics. Existing panda national nature reserves cover all but one of the endemic species that overlap with the panda's distribution. Of particular interest are 14 mammal, 20 bird, and 82 amphibian species that are inadequately protected. Most of these species the International Union for Conservation of Nature currently deems threatened. But 7 mammal, 3 bird, and 20 amphibian species are currently nonthreatened, yet their geographical ranges are <20,000 km2 after accounting for elevational restriction and remaining habitats. These species concentrate mainly in Sichuan, Yunnan, Nan Mountains, and Hainan. There is a high concentration in the east Daxiang and Xiaoxiang Mountains of Sichuan, where pandas are absent and where there are no national nature reserves. The others concentrate in Yunnan, Nan Mountains, and Hainan. Here, 10 prefectures might establish new protected areas or upgrade local nature reserves to national status.  相似文献   
15.
地方性砷中毒地区环境砷暴露健康风险研究进展   总被引:2,自引:0,他引:2  
自然因素引起的环境高砷暴露及其健康效应,尤其是饮水型地方性砷中毒是砷污染健康风险评估的基础。总结地方性砷中毒在环境砷暴露的风险识别、暴露途径和暴露与健康效应关系研究中的作用基础上,指出了地方性砷中毒研究中仅强调了饮水污染,关注的暴露途径比较单一,因此,人体多途径联合砷暴露的健康风险评估过程存在较大的不确定性。我国是唯一存在饮水和燃煤2种自然环境高砷暴露的国家,是研究2种类型砷暴露异同的天然场地,然而目前环境高砷的暴露及其健康效应的研究均为独立研究,对燃煤型地方性砷中毒在呼吸链砷暴露风险评估中的作用重视不够。因此,通过开展两种环境砷暴露及其健康效应的综合比较研究,建立呼吸链暴露评估和暴露-健康效应模型,可以为人体多途径联合砷暴露的健康风险研究提供新的依据。  相似文献   
16.
Despite its successes, the U.S. Endangered Species Act (ESA) has proven challenging to implement due to funding limitations, workload backlog, and other problems. As threats to species survival intensify and as more species come under threat, the need for the ESA and similar conservation laws and policies in other countries to function efficiently has grown. Attempts by the U.S. Fish and Wildlife Service (USFWS) to streamline ESA decisions include multispecies recovery plans and habitat conservation plans. We address species status assessment (SSA), a USFWS process to inform ESA decisions from listing to recovery, within the context of multispecies and ecosystem planning. Although existing SSAs have a single-species focus, ecosystem-based research can efficiently inform multiple SSAs within a region and provide a foundation for transition to multispecies SSAs in the future. We considered at-risk grassland species and ecosystems within the southeastern United States, where a disproportionate number of rare and endemic species are associated with grasslands. To initiate our ecosystem-based approach, we used a combined literature-based and structured World Café workshop format to identify science needs for SSAs. Discussions concentrated on 5 categories of threats to grassland species and ecosystems, consistent with recommendations to make shared threats a focus of planning under the ESA: (1) habitat loss, fragmentation, and disruption of functional connectivity; (2) climate change; (3) altered disturbance regimes; (4) invasive species; and (5) localized impacts. For each threat, workshop participants identified science and information needs, including database availability, research priorities, and modeling and mapping needs. Grouping species by habitat and shared threats can make the SSA process and other planning processes for conservation of at-risk species worldwide more efficient and useful. We found a combination of literature review and structured discussion effective for identifying the scientific information and analysis needed to support the development of multiple SSAs. Article impact statement: Species status assessments can be improved by an ecosystem-based approach that groups imperiled species by shared habitats and threats.  相似文献   
17.
我们曾就干旱因素影响两个地方性氟中毒(地氟病)病区人群的某些指标作过报道。本文重点讨论其影响同一人群尿、血清和唾液含氟量情况,旨在为地氟病防治研究提供参考。  相似文献   
18.
我国“硒与健康”数据库应用DATATRTIEVE数据管理系统管理数据;在VAX-11/780计算机上实现。它以我国公开刊物和文集为数据源。现存有五千个记录,约400种样品,遍及28个省市,主要反映的是克山病、大骨节病、硒中毒、某类癌症、心脏病等。依关键词:样品名、省、县、健康属性、分析方法等可以检索并输出所需样品含硒量数值报表。数据库能自动实现检索集合极大值、极小值选择,计算均值和标准差,进行单因素数据质量评价,并配有FORTRAN语言编写的模式识别为主的多元统计程序包,有助于多因素数据质量评价。  相似文献   
19.
经对呼和浩特盆地西部深层水1000km ̄2、浅层水600km ̄2范围内进行水质检测分析,发现其深、浅两层地下水均富砷,浅水有18.8%、深水有40.9%的水样砷含量超过国家饮用水卫生标准。测得水体总砷中以三价砷为主。溶解氧含量低,铁、锰离子为痕量,硫酸盐、亚硝酸盐氮含量也均低,同时有低硒、高氟现象,提示该地区为富含有机质的强还原环境,有利于砷的迁移富集,对饮水型砷中毒起着促进作用。  相似文献   
20.
Abstract: The level of endemism at a site may indicate species richness of the site. Nevertheless, assessing endemism levels in taxonomic groups such as plants may be difficult because the species richness of plants is high relative to species richness of other taxonomic groups (e.g., vertebrates). A major problem in determining whether plant species are endemic is the lack of standardization of the geographic extent of endemism: species are considered endemic to, for example, countries, continents, or states. We compiled a history of the concept of endemism as it applies to plants. The application of the concept to geographic distribution dates from the 19th century, when European explorers discovered many taxa exclusive to regions outside Europe. Two types of endemism, paleoendemism and neoendemism, were then acknowledged, according to evolutionary age, and these categories are still in use. In the 20th century, most of the research on endemism focused on explaining range restriction on the basis of cytological data, edaphic and geological factors, and phylogeny. This research led to a vast number of concepts, of which only edaphic endemism remains relatively well accepted. More recently, researchers suggest that competition may determine endemism in some cases. We suggest that plants be labeled as endemic only if their distribution occurs in a distinct ecological unit, such as a biome. On the basis of a literature review of the factors that cause range restriction, we categorized endemic taxa as paleoendemic, neoendemic, edaphically endemic, or suppressed endemic. For example, Schlechtendalia luzulifolia, is a rare forb that is a paleoendemic species of the granite and sandstone‐based grasslands of the Pampa. Levels of endemism in southern Brazilian grasslands are poorly known. We emphasize the importance of recognizing these grasslands as a single transnational biome so that levels of endemism of species therein can be assessed correctly.  相似文献   
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