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641.
岩溶多重介质环境涉及到气候、土壤、植被、岩性及水-岩相互作用多项内容。在岩溶多重介质环境中,水-岩相互作用不断地改变岩溶多重介质环境的结构与功能。在岩溶化高度成熟地区,水-岩相互作用强烈,致使岩溶多重介质环境重建。岩溶灾害的时空演变是在岩溶多重介质环境中进行的,研究岩溶多重介质环境,可分析岩溶灾害发生和发展的规律,及其破坏性和预防与治理措施。 相似文献
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644.
青藏高原的隆起对中国沙漠与沙漠化时空格局的影响 总被引:6,自引:0,他引:6
本文指出,中国沙漠与沙漠化分布呈“V”型格局,而青藏高原的隆起对中国沙漠与沙漠化格局的形成具有决定性的作用。青藏高原的隆起为中国沙漠与沙漠化的形成创造了丰富的沙地基质,促进了我国东南季风的形成及其他相应的气候变化,气候的变化直接的影响了我国地质时期沙漠的形成,并且通过影响我国北方早期人类活动的集聚格局间接影响了我国历史时期沙漠化的发展。 相似文献
645.
Nine lakes in the Arkhangelsk oblast were analyzed with respect to their morphometry, hydrology, and hydrochemistry, and their zooplankton was studied for three years. The data on zooplankton abundance, biomass, the ratio of filter-feeders and predators, the Shannon index of species diversity, and average individual weight of zooplankters were obtained. Differences in the structure of zooplanktonic cenoses were revealed in lakes differing in morphometric parameters, prevailing ions (HCO3
–, SO4
2–), and their concentration. 相似文献
646.
Tamim Younos Fred W. Kaurish Terri Brown Raymond de Leon 《Journal of the American Water Resources Association》2001,37(2):327-334
ABSTRACT: Karst terrane provides a linkage between surface water and ground water regimes by means of caves, sinkholes and swallets, and sinking streams, and facilitates the inter‐watershed transfer of water and contaminants through these subsurface systems. The goal of this study was to develop procedures to identify the sources of degradation of a creek situated in a complex karst‐water system. The study approach consisted of using dye tracing technique to determine subsurface flow paths through the karst system, a water‐sampling network to identify and characterize pollution sources within the surface watershed and subsurface flow regime, and evaluation of analytical data for several water quality parameters. The results of this study provide an interesting perspective of water and contaminant movement in karst‐water systems and pinpoint the sources of stream contamination for a case study site in southwest Virginia where two springs supply water to a contaminated freshwater stream. 相似文献
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648.
岩溶区土壤允许流失量与土地石漠化的关系 总被引:1,自引:0,他引:1
为了解岩溶区土壤允许流失量(T值)与土地石漠化的关系,根据岩溶土壤圈系统论,采用实地调查与GIS空间分析技术,结合贵州碳酸盐岩岩石组合类型测算了T值,并探讨了其对石漠化的影响。结果发现:①岩溶区的T值可分为三大类,在极纯、较纯和不纯的碳酸盐岩地区,T值分别为20、100和250 t·km-2·a-1,在无土可流、完全是石山的地区,T值只有几吨或更低;②在T=20、100和250 t·km-2·a的地区,石漠化发生率分别为29.86%、28.12%和23.25%,石漠化严重度分别为73.55%、60.57%和52.19%。因此,岩溶区的T值总体偏小,且具有多样性和异质性的空间分布特点;在相同社会背景下或不考虑人类活动的干扰差异,T值对石漠化的发生率和严重度有明显影响,T值越低,阈值越小,抗干扰能力越弱,石漠化的发生率越高,程度也越严重。 相似文献
649.
运用决策树分类法对1990年,2000年,2006年3期遥感影像进行分类,寻求生态输水对塔里木河下游沙漠化进程的影响.结果表明,2000年生态输水后沙漠化速度减缓,但沙漠化进程仍在继续.沙漠化变化方向主要为非沙漠化→轻度沙漠化→中度沙漠化→重度沙漠化→极重度沙漠化,生态输水后正向变化减小,逆向变化量增加.沙漠化变化区域主要集中在绿洲边缘和河道两侧,生态输水后变化区域离绿洲边缘和河道更近.沙漠化与距河道距离密切相关,距河道越远沙漠化退化越严重;生态输水后,距离河道1 km内的沙漠化得到抑制并出现逆转. 相似文献
650.
Thomas J. Burbey Tamim Younos Eric T. Anderson 《Journal of the American Water Resources Association》2000,36(5):1161-1172
ABSTRACT: Discharge from flooded abandoned subsurface coal mines is considered a potential source for water supplies where other acceptable water sources are not available. The objective of this study was to develop procedures for determining sustainability of mine‐water discharge using rainfall and discharge data for a case study site. The study site is located in southwest Virginia where Late Paleozoic sequences of sandstone, coal, and shale predominate. A rain gauge and a flow rate monitoring system were installed at the site and data were collected for a period of 100 days. The recording period corresponded with one of the driest periods in recent years and, therefore, provided valuable information regarding the flow sustainability during baseflow conditions. From available data on underground mining patterns, geology, and ground water flow regimes, it was determined that a coal mine aquifer exhibits hydraulic characteristics very similar to the extremely heterogeneous systems observed in karst aquifers, and the mine discharge is analogous to springflow. Thus, techniques commonly used in karst‐water systems and springflow analysis were used to develop rainfall/mine‐discharge relationships. Springflow recession analysis was performed on five rainfall recessions and the coefficient for each recession was compared and interpreted in light of known geologic information. It was found that the recession coefficients described the mine discharge adequately and the mine aquifer response to a rainfall pulse was very similar to the response from certain types of karst aquifers. A cross‐correlation analysis was performed to verify the results of the recession analysis and to develop a “black box” statistical model for discharge data. The correlation analysis proved the validity of springflow recession analysis for mine discharge. The recorded data length was not adequate to create a statistical model, however, but a procedure was proposed for a statistical model that could be used with large flow records. For the study site, the mine discharge was found to be sustainable for a prolonged period of time. 相似文献