全文获取类型
收费全文 | 15321篇 |
免费 | 588篇 |
国内免费 | 5999篇 |
专业分类
安全科学 | 974篇 |
废物处理 | 957篇 |
环保管理 | 1219篇 |
综合类 | 8545篇 |
基础理论 | 2693篇 |
环境理论 | 2篇 |
污染及防治 | 5763篇 |
评价与监测 | 591篇 |
社会与环境 | 532篇 |
灾害及防治 | 632篇 |
出版年
2024年 | 11篇 |
2023年 | 237篇 |
2022年 | 722篇 |
2021年 | 593篇 |
2020年 | 448篇 |
2019年 | 462篇 |
2018年 | 568篇 |
2017年 | 695篇 |
2016年 | 847篇 |
2015年 | 1048篇 |
2014年 | 1192篇 |
2013年 | 1672篇 |
2012年 | 1307篇 |
2011年 | 1381篇 |
2010年 | 994篇 |
2009年 | 981篇 |
2008年 | 1059篇 |
2007年 | 956篇 |
2006年 | 872篇 |
2005年 | 631篇 |
2004年 | 429篇 |
2003年 | 558篇 |
2002年 | 489篇 |
2001年 | 414篇 |
2000年 | 443篇 |
1999年 | 479篇 |
1998年 | 439篇 |
1997年 | 358篇 |
1996年 | 342篇 |
1995年 | 293篇 |
1994年 | 237篇 |
1993年 | 190篇 |
1992年 | 156篇 |
1991年 | 90篇 |
1990年 | 71篇 |
1989年 | 54篇 |
1988年 | 47篇 |
1987年 | 30篇 |
1986年 | 26篇 |
1985年 | 13篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
791.
The chemical forms and ecological risk of As were characterized in the sediment of the Daliao River System (DRS), which has
been affected by long-term intensive industrial, urban, and agricultural activities. Twenty-seven samples of surface sediment
were collected and analyzed for total As content and that of its chemical forms. The results indicated that the average total
As content in the sediment was 9.83 mg kg − 1 but that the levels ranged from 1.57 to 83.09 mg kg − 1. At the sites near cities, mining sites, and the estuary of the DRS, it is likely that adverse effects on aquatic organisms
occur, due to As levels in the sediment that are often higher than the threshold effect level and occasionally higher than
the probable effect level. A selectively sequential extraction indicated that the majority of As in the sediment was bound
to Fe oxides (62.1%), with moderate proportions of residual As (19.8%), specifically adsorbed As (17.9%), and a low proportion
of non-specifically adsorbed As (1.1%). In addition, the content of Fe in the sediment was positively and significantly correlated
with the contents of amorphous and crystalline Fe oxide-bound As, confirming the crucial role of Fe oxides in immobilizing
high amounts of As in superficial environments. The average molar ratio of As to Fe was 1.18 × 10 − 4 in the surface sediment of the DRS, similar to that of natural Fe oxides, but much lower than that of synthesized Schwertmannite.
Therefore, the release of As under reduced and low pH conditions can cause serious problems for water resources and for living
organisms. 相似文献
792.
Dongqi Wang Yanling He Jidong Liang Pei Liu Pengyu Zhuang 《Environmental monitoring and assessment》2013,185(2):1041-1053
To study the status and source of aluminum (Al) contamination, a total of 21 sampling sites along six rivers near Xi’an City (Shaanxi province, China) were investigated during 2008–2010. The results indicated that the average concentration of total Al (Alt) in the six rivers increased by 1.6 times from 2008 to 2010. The spatial distribution of Alt concentrations in the rivers near Xi’an City was significantly different, ranged from 367 μg/L (Bahe River) to 1,978 μg/L (Taiping River). The Alt concentration was highest near an industrial area for pulp and paper-making (2,773 μg/L), where the Al level greatly exceeded the water quality criteria of both the USA (Criterion Continuous Concentration, 87 μg/L) and Canada (100 μg/L). The average concentration of inorganic monometric aluminum (Alim) was 72 μg/L which would pose threats to fishes and other aquatic lives in the rivers. The concentrations of exchangeable Al (Alex) in the sediment of the Taiping River sampled were relatively high, making it to be an alternative explanation of increasing Al concentrations in the rivers near Xi’an City. Furthermore, an increasing Al level has been detected in the upstream watershed near Xi’an City in recent years, which might indicate another notable pollution source of Al. 相似文献
793.
Gustavo M. Riggio Judith C. Chow Paul M. Cropper Xiaoliang Wang Reddy L.N. Yatavelli Xufei Yang 《Journal of the Air & Waste Management Association (1995)》2018,68(5):463-476
A thermal/optical carbon analyzer (TOA), normally used for quantification of organic carbon (OC) and elemental carbon (EC) in PM2.5 (fine particulate matter) speciation networks, was adapted to direct thermally evolved gases to an electron impact quadrupole mass spectrometer (QMS), creating a TOA-QMS. This approach produces spectra similar to those obtained by the Aerodyne aerosol mass spectrometer (AMS), but the ratios of the mass to charge (m/z) signals differ and must be remeasured using laboratory-generated standards. Linear relationships are found between TOA-QMS signals and ammonium (NH4+), nitrate (NO3?), and sulfate (SO42-) standards. For ambient samples, however, positive deviations are found for SO42-, compensated by negative deviations for NO3?, at higher concentrations. This indicates the utility of mixed-compound standards for calibration or separate calibration curves for low and high ion concentrations. The sum of the QMS signals across all m/z after removal of the NH4+, NO3?, and SO42- signals was highly correlated with the carbon content of oxalic acid (C?H?O?) standards. For ambient samples, the OC derived from the TOA-QMS method was the same as the OC derived from the standard IMPROVE_A TOA method. This method has the potential to reduce complexity and costs for speciation networks, especially for highly polluted urban areas such as those in Asia and Africa.Implications: Ammonium, nitrate, and sulfate can be quantified by the same thermal evolution analysis applied to organic and elemental carbon. This holds the potential to replace multiple parallel filter samples and separate laboratory analyses with a single filter and a single analysis to account for a large portion of the PM2.5 mass concentration. 相似文献
794.
This study investigated the levels, sources and ecological risks of 16 polycyclic aromatic hydrocarbons (PAHs) in two sediment cores that were collected along the Huaxi Reservoir. The spatial distributions and residue levels of the 16 priority PAHs in the sediments from the Huaxi Reservoir were analyzed for their potential ecological risk, source apportionment and contribution to the total PAH residue. The concentration level of the total PAHs (TPAHs) was in the range 1805 ng·g?1 to 20023 ng·g?1 based on dry weight, and the content of PAHs in the Huaxi Reservoir exhibited a gradual upward trend. The PAH congener ratios fluoranthene/(fluoranthene + pyrene) and indeno[1, 2, 3-cd]pyrene/(indeno[1, 2, 3-cd]pyrene + benzo[g, h, i]perylene) were used to identify the source. The main source of the low molecular weight PAHs was wood and coal combustion, whereas the high molecular weight PAHs were primarily from petroleum combustion sources. The results of an ecological risk assessment demonstrated that ACE poses a potential ecological risk, while FLU, NAP, ANT, BaP, DBA, PHEN and PYR can have serious ecological risks. 相似文献
795.
Qin Wei Huidan Deng Hengmin Cui Jing Fang Zhicai Zuo Junliang Deng Yinglun Li Xun Wang Ling Zhao 《Environmental science and pollution research international》2018,25(34):33926-33935
Fluorine or fluoride can have toxic effects on bone tissue and soft tissue at high concentrations. These negative effects include but not limited to cytotoxicity, immunotoxicity, blood toxicity, and oxidative damage. Apoptosis plays an important role in fluoride-induced toxicity of kidney, liver, spleen, thymus, bursa of Fabricius, cecal tonsil, and cultured cells. Here, apoptosis activated by high level of fluoride has been systematically reviewed, focusing on three pathways: mitochondrion-mediated, endoplasmic reticulum (ER) stress-mediated, and death receptor-mediated pathways. However, very limited reports are focused on the death receptor-mediated apoptosis pathways in the fluoride-induced apoptosis. Therefore, understanding and discovery of more pathways and molecular mechanisms of fluoride-induced apoptosis may contribute to designing measures for preventing fluoride toxicity. 相似文献
796.
Han Jiangpei Shi Liangsheng Wang Yakun Chen Zhuowei Wu Laosheng 《Environmental science and pollution research international》2018,25(15):14511-14520
Environmental Science and Pollution Research - Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen... 相似文献
797.
Loganathan Paripurnanda Shim Wang Geun Sounthararajah Danious Pratheep Kalaruban Mahatheva Nur Tanjina Vigneswaran Saravanamuthu 《Environmental science and pollution research international》2018,25(17):16664-16675
Environmental Science and Pollution Research - Elevated concentrations of heavy metals in water can be toxic to humans, animals, and aquatic organisms. A study was conducted on the removal of Cu,... 相似文献
798.
A graphics processing unit (GPU) accelerated two-dimensional contamination transport model is developed using the lattice Boltzmann method (LBM). The intrinsic parallel features of LBM make it particularly suitable for implementation on GPUs. After validation with two benchmarks, the model was applied to a cyanide-release accident in the Danjiangkou Reservoir, using a numerical combination of hydrodynamics and solute transport. The results show good agreement with an Environmental Fluid Dynamics Code (EFDC) model. A single GPU workstation speedup reaches 1.58 times that of a central processing unit (CPU) calculation alone. This speedup provides the opportunity for applying the model as a pollution accident information and decision support system for the Middle Route of the South to North Water Diversion Project in China. 相似文献
799.
Na Wang You-Gan Wang Shuwen Hu Zhi-Hua Hu Jing Xu Hongwu Tang Guangqiu Jin 《Environmental Modeling and Assessment》2018,23(6):779-786
We introduce robust procedures for analyzing water quality data collected over time. One challenging task in analyzing such data is how to achieve robustness in presence of outliers while maintaining high estimation efficiency so that we can draw valid conclusions and provide useful advices in water management. The robust approach requires specification of a loss function such as the Huber, Tukey’s bisquare and the exponential loss function, and an associated tuning parameter determining the extent of robustness needed. High robustness is at the cost of efficiency loss in parameter loss. To this end, we propose a data-driven method which leads to more efficient parameter estimation. This data-dependent approach allows us to choose a regularization (tuning) parameter that depends on the proportion of “outliers” in the data so that estimation efficiency is maximized. We illustrate the proposed methods using a study on ammonium nitrogen concentrations from two sites in the Huaihe River in China, where the interest is in quantifying the trend in the most recent years while accounting for possible temporal correlations and “irregular” observations in earlier years. 相似文献
800.
Y. Chen H. R. Jia S. Niu X. Zhang H. L. Wang Y. Z. Ye Q. S. Chen Z. L. Yuan 《Russian Journal of Ecology》2018,49(1):40-46
Species turnover patterns can be inconsistent due to differences in the dispersal ability of different growth forms. Here, species of trees, shrubs, herbs, and bryophytes in the Xiaoqinling National Nature Reserve in China were analyzed to determine patterns of species turnover along an elevation and spatial gradient. Variance partitioning was used to assess the relative contribution of topographic heterogeneity and dispersal limitation to species turnover. Our results suggest that the effect of dispersal limitation is more important than topographic heterogeneity on species turnover in temperate mountane ecosystems in the study area. Dispersal limitation has a greater effect on trees species turnover than on shrubs, herbs or bryophytes species turnover. 相似文献