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761.
Abstract The purpose of this study is merely to review the current situation in the designing and implementation of the emission trading programs in Europe. Historical data show that although there is a series of shortcomings in their current functioning, employing such instruments for GHG reduction policy making is strongly expected to be efficient and effective. The European Union Emission Trading Scheme (EU ETS), Clean Development Mechanism (CDM) and Joint Implementation (JI) are just a few examples of the ambitious EU initiative that heavily relies on such instruments. We dwell on their operations and achievements by far and all the content in this article is expected to convince the Chinese government and regional public authorities to take positive actions and attitudes in promoting these instruments. 相似文献
762.
不同生物炭对磷的吸附特征及其影响因素 总被引:1,自引:1,他引:0
为了实现植物生物质资源化利用,选择5种生物质材料制备生物炭,通过比较5种生物炭材料的磷吸附能力,筛选出了2种磷吸附效果较佳的材料,并探明了筛选生物炭材料的理化性质及其对磷的吸附特征.结果表明,5种生物炭材料中,仅水稻秸秆和玉米秸秆生物炭对磷具有吸附能力.Langmuir等温吸附曲线表明,水稻秸秆生物炭对废水中磷的吸附能力强于玉米秸秆生物炭,理论最大吸附量为:水稻秸秆生物炭(9.78 mg·g-1)>玉米秸秆生物炭(0.39 mg·g-1).水稻秸秆生物炭的比表面积(148.30 m2·g-1)和总孔体积(0.11 cm3·g-1)远高于玉米秸秆生物炭8.26 m2·g-1和0.03 cm3·g-1,同时水稻秸秆生物炭有更高的Mg、 Ca、 Fe和Al元素含量.水稻秸秆生物炭和玉米秸秆生物炭对磷吸附的最佳pH为酸性;在不同的pH范围内(3.0~11.0),水稻秸秆生... 相似文献
763.
为探究丹江口库区土壤中微塑料赋存特征及影响因素,通过对果园、旱地、水田和湿地进行土壤样品采集,利用密度分选、显微镜观察和拉曼光谱仪测定等方法对土壤中微塑料进行鉴定.结果表明,研究区采集的64个样本均有微塑料检出,丰度范围为645~15161 n·kg-1.空间分布上,库尾高于库中和库首,且表层土壤(0~20 cm)中微塑料的丰度明显低于下层土壤(20~40 cm).微塑料主要类型为聚丙烯(26.4%)和聚酰胺(20.2%),粒径主要集中在50~500 μm之间(75%),常见形状为碎片状(66.2%).相关性分析显示,土壤微塑料丰度与土地利用、距水面和住宅的距离、人口密度和土壤性状密切相关.从微塑料污染风险来看,72.1%区域微塑料聚合物污染指数处于Ⅲ级和Ⅳ级,丹江口库区存在一定的微塑料污染风险.研究结果可为微塑料风险评估提供支撑. 相似文献
764.
Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance 总被引:2,自引:0,他引:2
Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets. 相似文献
765.
766.
Optimizing model for land use/land cover retrieval from remote sensing imagery based on variable precision rough sets 总被引:2,自引:0,他引:2
The suitable spectral mode in remote sensing is often desirable to facilitate the inversion of ecological environment and landscape. This paper put forward an optimizing model based on variable precision rough sets (VPRS) for the land cover discrimination in wetland inventory. In the case study of Lake Baiyangdian which has important ecological functions to the northern China, this model is established successfully according to the domain-experts knowledge. The procedure is as follows. First step is data collection, including remote-sensing data (e.g., Landsat-5 TM bands), the digitized relief maps, and statistical yearbooks. Second, the remote sensing imagery (RSI) and relief maps are co-registered into the same resolution. Third, a condition set, including various attributes is derived from spectral bands, band math or ratio indices based on previous studies, at the same time, the decision set is derived from true land types after investigation and validation. Then, the remote sensing decision table (RSDT) is constructed by linking condition set with decision set according to the sequential pixels in RSI. Fourth, we create one forward greedy searching algorithm based on VPRS to handle this RSDT. After adjusting parameters such as β and knowledge granularity diameter (KGD), we obtain the stable optimized results. Comparative experiments and evaluation show that the discrimination or retrieval accuracy of VPRS model is satisfying (overall accuracy: 87.32% and KHAT: 0.84) and better than original data. Moreover, data dimension has been decreased dramatically (from 12 to 3) and key attributes found by the model may be useful for specific retrieval in wetland inventories. 相似文献
767.
Feng Qin Shujuan Wang Inna Kim Hallvard F. Svendsen Changhe Chen 《International Journal of Greenhouse Gas Control》2011,5(3):405-412
A reaction calorimeter was used to determine the enthalpies of absorption of CO2 in aqueous ammonia and in aqueous solutions of ammonium carbonate at temperatures of 35–80 °C. The heat of absorption of CO2 with 2.5 wt% aqueous ammonia solution was found to be about 70 kJ/mol CO2, which is lower than that with MEA (around 85 kJ/mol) at 35 and 40 °C. The value decreases with increased loading, but not to as low a value as expected by the carbonate–bicarbonate reaction (26.88 kJ/mol). The enthalpy of absorption of CO2 in aqueous ammonia at 60 and 80 °C decreases with loadings at first, then increases between 0.2 mol CO2/mol NH3 and 0.6 mol CO2/mol NH3, and then decreases again. The behavior of the heat of absorption of CO2 in 10 wt% ammonium carbonate solution was found to be the same as that of aqueous ammonia at loadings above 0.6 mol CO2/mol NH3. The heat of absorption increases with increasing temperature. The heats of absorption are directly related to the extent of the various reactions with CO2 and can be assessed from the species variation in the liquid phase. 相似文献
768.
Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau 总被引:2,自引:0,他引:2
Qianggong Zhang Shichang Kang Chaoliu Li Feng Chen Zuzana Boukalova Ivo ?erny 《Environmental monitoring and assessment》2011,173(1-4):301-313
In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements(Ca and Mg), and nutrient(NO $_{3}^{-})$ were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007?C2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1?C22) and anthropogenic action (sites 23?C76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO $_{3}^{-}$ and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively. 相似文献
769.
Xu H Bi XH Feng YC Lin FM Jiao L Hong SM Liu WG Zhang XY 《Environmental monitoring and assessment》2011,183(1-4):581-592
To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH??, Ca2?, Mg2?, Na?, K?, SO?2?, NO??, F?, and Cl?). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO?2?/NO?? ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO?2?, Ca2?, and Mg2? and 33.7% of K? were of non-sea origins, while all Na? and Cl? and 66.3% of K? originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources. 相似文献
770.