首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   40篇
  免费   3篇
  国内免费   2篇
大气科学   1篇
地球物理   15篇
地质学   11篇
海洋学   11篇
综合类   1篇
自然地理   6篇
  2024年   1篇
  2023年   1篇
  2022年   1篇
  2020年   3篇
  2019年   1篇
  2017年   1篇
  2014年   4篇
  2013年   4篇
  2012年   2篇
  2010年   1篇
  2008年   5篇
  2006年   3篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   3篇
  1996年   1篇
  1988年   2篇
  1986年   1篇
排序方式: 共有45条查询结果,搜索用时 312 毫秒
41.
《Marine pollution bulletin》2013,76(1-2):291-300
Surface water samples were collected from substations along Sheva creek and Dharamtar creek mangrove ecosystems of Uran (Raigad), Navi Mumbai, west coast of India. Water samples were collected fortnightly from April 2009 to March 2011 during spring low and high tides and were analyzed for pH, Temperature, Turbidity, Total solids (TS), Total dissolved solids (TDS), Total suspended solids (TSS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Carbon dioxide (CO2), Chemical oxygen demand (COD), Salinity, Orthophosphate (O-PO4), Nitrite–nitrogen (NO2–N), Nitrate–nitrogen (NO3–N), and Silicates. Variables like pH, turbidity, TDS, salinity, DO, and BOD show seasonal variations. Higher content of O-PO4, NO3–N, and silicates is recorded due to discharge of domestic wastes and sewage, effluents from industries, oil tanking depots and also from maritime activities of Jawaharlal Nehru Port Trust (JNPT), hectic activities of Container Freight Stations (CFS), and other port wastes. This study reveals that water quality from mangrove ecosystems of Uran is deteriorating due to industrial pollution and that mangrove from Uran is facing the threat due to anthropogenic stress.  相似文献   
42.
2022年气象联合基金资助数值预报模式关键技术、灾害天气监测预报理论与方法和人工智能气象应用技术三个核心领域,共接收申请64项,其中不同单位属性的合作申请占87.5%。申请书关键词分析发现,气象联合基金与地球科学部“天气及气候系统与可持续发展”领域重点项目既有较强的联系,又有明显的区别。气象联合基金评审过程与地球科学部常规重点基金评审过程相似。经过通讯评审和会评,共资助14项重点支持项目,资助率21.9%,平均资助强度264.6万元/项,年均资助强度超过了地球科学部常规重点项目的资助强度。  相似文献   
43.
长江河口及其上海岸带水体沉积物中磷的存在形态   总被引:13,自引:0,他引:13  
讨论了磷的 5种存在形态及其分布规律。河口及岸带水体沉积物中磷主要是以有机磷 (OP)和无机磷 (IP)形式存在的 ,有机磷是有机质的组成部分 ,无机磷又可分为可溶性磷(DP)、铁结合磷 (Fe P)、铝结合磷 (Al P)、钙结合磷 (Ca P)。研究发现 ,沉积物中总磷含量水平在 6 92 79~ 1570 99μg/g之间 ,无机磷含量在 2 2 0 0 2~ 92 8 33μg/g之间 ,占总磷含量的31 8%~ 6 0 5% ,而有机磷含量在 394 89~ 6 4 2 6 6 μg/g之间 ,为总磷含量的 39 5%~ 6 8 2 %。在分析水体沉积物中各形态磷的含量和变化的基础上 ,对磷在时空上的变化、与有机碳、总氮的关系以及污水输入影响等进行了初步的论述 ,并提出沉积物中铁结合磷 (Fe P)和铝结合磷 (Al P)可作为判断污染的指标之一。  相似文献   
44.
《Marine pollution bulletin》2014,80(1-2):333-337
This study examined the Pb content and Pb isotopic composition in a sediment core taken from the East China Sea (ECS) shelf, and it was observed that since 2003 the increasing anthropogenic Pb inputs have impacted as far as the ECS shelf sediments. The ECS shelf sediments were generally characterized with low bulk Pb contents (12.5–15.0 μg/g) and relatively lithogenic Pb isotopic signatures (both HCl-leached and residual fractions). However, elevated Pb records along with lighter Pb isotopic signals have occurred in the post-2003 sediments, as a result of a small but increasing anthropogenic Pb contribution from the heavily human perturbed coastal sediments due to the sharply increasing coal consumption in mainland China since 2003.  相似文献   
45.
This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio 87Sr/86Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The 87Sr/86Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号