全文获取类型
收费全文 | 2344篇 |
免费 | 74篇 |
国内免费 | 206篇 |
专业分类
安全科学 | 92篇 |
废物处理 | 110篇 |
环保管理 | 237篇 |
综合类 | 556篇 |
基础理论 | 458篇 |
环境理论 | 3篇 |
污染及防治 | 791篇 |
评价与监测 | 206篇 |
社会与环境 | 149篇 |
灾害及防治 | 22篇 |
出版年
2023年 | 31篇 |
2022年 | 73篇 |
2021年 | 95篇 |
2020年 | 49篇 |
2019年 | 52篇 |
2018年 | 54篇 |
2017年 | 81篇 |
2016年 | 90篇 |
2015年 | 93篇 |
2014年 | 138篇 |
2013年 | 247篇 |
2012年 | 171篇 |
2011年 | 179篇 |
2010年 | 133篇 |
2009年 | 125篇 |
2008年 | 161篇 |
2007年 | 120篇 |
2006年 | 143篇 |
2005年 | 95篇 |
2004年 | 71篇 |
2003年 | 71篇 |
2002年 | 86篇 |
2001年 | 40篇 |
2000年 | 22篇 |
1999年 | 26篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1964年 | 6篇 |
1960年 | 1篇 |
1959年 | 3篇 |
1958年 | 2篇 |
1956年 | 1篇 |
1953年 | 1篇 |
1951年 | 1篇 |
1929年 | 1篇 |
1920年 | 2篇 |
排序方式: 共有2624条查询结果,搜索用时 15 毫秒
111.
The halophytic shrub Halimione portulacoides is known to be capable of growth in soils containing extremely high concentrations of Zn. This study evaluated in detail the tolerance and accumulation potential of H. portulacoides under moderate and high external Zn levels. A greenhouse experiment was conducted in order to investigate the effects of a range of Zn concentrations (0-130 mmol L−1) on growth and photosynthetic performance by measuring relative growth rate, total leaf area, specific leaf area, gas exchange, chlorophyll fluorescence parameters and photosynthetic pigment concentrations. We also determined the total zinc, nitrogen, phosphorus, calcium, magnesium, sodium, potassium, iron and copper concentrations in the plant tissues. H. portulacoides demonstrated hypertolerance to Zn stress, since it survived with leaf concentrations of up to 2300 mg Zn kg−1 dry mass, when treated with 130 mmol Zn L−1. Zinc concentrations greater than 70 mmol L−1 in the nutrient solution negatively affected plant growth, in all probability due to the recorded decline in net photosynthesis rate. Our results indicate that the Zn-induced decline in the photosynthetic function of H. portulacoides may be attributed to the adverse effect of the high concentration of the metal on photosynthetic electron transport. Growth parameters were virtually unaffected by leaf tissue concentrations as high as 1500 mg Zn kg−1 dry mass, demonstrating the strong capability of H. portulacoides to protect itself against toxic Zn concentrations. The results of our study indicate that this salt-marsh shrub may represent a valuable tool in the restoration of Zn-polluted areas. 相似文献
112.
Annekatrin Wagner Stephan Hülsmann Lothar Paul Rüdiger J. Paul Thomas Petzoldt René Sachse Thomas Schiller Bettina Zeis Jürgen Benndorf Thomas U. Berendonk 《Marine Biology》2012,159(11):2543-2559
To predict the coherence in local responses to large-scale climatic forcing among aquatic systems, we developed a generalized approach to compare long-term data of dimictic water bodies based on phenomenologically defined hydrographic events. These climate-sensitive phases (inverse stratification, spring overturn, early thermal stratification, summer stagnation) were classified in a dual code (cold/warm) based on threshold temperatures. Accounting for a latitudinal gradient in seasonal timing of phases derived from gradients in cumulative irradiation (2.2?days per degree latitude), we found a high spatial and temporal coherence in warm–cold patterns for six lakes (84?%) and the Baltic Sea (78?%), even when using the same thresholds for all sites. Similarity to CW-codes for the North Sea still was up to 72?%. The approach allows prediction of phase-specific warming trends and resulting instantaneous or time-delayed ecological responses. Exemplarily, we show that warming during early thermal stratification controls food-web-mediated effects on key species during summer. 相似文献
113.
114.
115.
116.
Alessandra A. Z. Rodrigues André Fernando De Oliveira Antônio Augusto Neves Fernanda F. Heleno Laércio Zambolim 《Journal of environmental science and health. Part. B》2017,52(12):850-857
This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters. 相似文献
117.
118.
以TiO2为载体,选取过渡金属元素Mn为活性组分,稀土金属元素Ce为活性助剂,采用分步共混法制备了Mn-Ce/TiO2催化剂(活性组分负载量16%),系统研究了TiO2载体的晶型和晶粒尺寸对催化剂脱硝活性的影响。实验结果表明:分别以锐钛矿型和金红石型TiO2为载体制备的催化剂,其低温脱硝活性相差不大,活性组分均以无定型态高度分散于载体中,以金红石型TiO2为载体制备的催化剂中部分TiO2转变为锐钛矿型;以不同晶粒尺寸TiO2载体制备的催化剂的低温脱硝活性相差较大,比表面积较大、晶粒尺寸较小的TiO2载体制备的催化剂,其脱硝活性低于晶粒尺寸较大的TiO2载体制备的催化剂。 相似文献
119.
在脱硫脱硝喷淋装置上采用氨法-络合法处理工业烟气。考察了吸收液pH、Fe(Ⅱ)EDTA浓度、初始烟气浓度、液气比对烟气同时脱硫脱硝效果的影响。实验结果表明:吸收液的酸碱度通过影响Fe(Ⅱ)与EDTA的络合形式进而影响NO去除率;SO_2去除率主要受吸收液pH和初始SO_2质量浓度的影响;当吸收液pH大于8、吸收液Fe(Ⅱ)EDTA浓度大于0.100 mol/L、初始SO_2质量浓度小于1 500 mg/m3、初始NO质量浓度为1 200 mg/m3时,SO_2去除率均在95%以上,NO去除率为54%;当液气比由1 L/m3增大至4 L/m3时,有效脱硫时间和有效脱硝时间分别增长了7 min和4 min。 相似文献
120.
Aourell Mauffret André Rottiers Thomas Federle David C. Gillan Miriam Hampel Julian Blasco Ali Temara 《Environment international》2009,35(6):885-892
An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [14C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (109 bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL). 相似文献