全文获取类型
收费全文 | 1564篇 |
免费 | 36篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 56篇 |
废物处理 | 84篇 |
环保管理 | 186篇 |
综合类 | 332篇 |
基础理论 | 296篇 |
环境理论 | 1篇 |
污染及防治 | 390篇 |
评价与监测 | 156篇 |
社会与环境 | 99篇 |
灾害及防治 | 24篇 |
出版年
2023年 | 14篇 |
2022年 | 18篇 |
2021年 | 31篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 46篇 |
2017年 | 60篇 |
2016年 | 60篇 |
2015年 | 35篇 |
2014年 | 67篇 |
2013年 | 112篇 |
2012年 | 55篇 |
2011年 | 111篇 |
2010年 | 75篇 |
2009年 | 74篇 |
2008年 | 87篇 |
2007年 | 83篇 |
2006年 | 55篇 |
2005年 | 62篇 |
2004年 | 68篇 |
2003年 | 74篇 |
2002年 | 63篇 |
2001年 | 61篇 |
2000年 | 32篇 |
1999年 | 30篇 |
1998年 | 21篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1970年 | 2篇 |
1967年 | 2篇 |
1962年 | 5篇 |
1961年 | 2篇 |
1924年 | 2篇 |
排序方式: 共有1624条查询结果,搜索用时 437 毫秒
541.
542.
543.
Investigation of the Aerobic Biodegradability of Several Types of Cyclodextrins in a Laboratory-Controlled Composting Test 总被引:1,自引:0,他引:1
Steven Verstichel Bruno De Wilde Eva Fenyvesi József Szejtli 《Journal of Polymers and the Environment》2004,12(2):47-55
The biodegradation of several types of cyclodextrins (CDs) under laboratory-controlled composting conditions was investigated. CDs are used in a broad range of applications in food, pharmaceutical, medical, chemical, and textile industries because of their specific chemical characteristics related to their hydrophobic interior and hydrophilic exterior. The three naturally occurring cyclodextrins -CD, -CD, and -CD proved to be completely and readily biodegradable. Chemical modification of these basic compounds can have a major impact on the biodegradation rate and final biodegradation percentage. Fully acetylated -CD and -CD were found to be nonbiodegradable during 45 days of composting. Reducing the degree of acetylation had a positive effect on the biodegradation. Complete biodegradation was obtained for partially acetylated -CD with a degree of substitution (DS) of 7. The methylation (DS = 13) of -CD resulted in an undegradable compound during the 47 days composting, while (2-hydroxy)propyl--CD reached a plateau in biodegradation at a percentage of 20%. The incorporation of the antimicrobial agents imazalil and allyl-isothiocyanate into -CD had no negative impact on biodegradation, which makes these antimicrobial agents/CD complexes suitable for incorporation into biodegradable active packaging. 相似文献
544.
Evaluation of the effect of a cover layer on radon exhalation from uranium mill tailings: transient radon flux analysis 总被引:1,自引:0,他引:1
An experimental study concerning the transport of 222Rn in uranium mill tailings (UMTs) and in the cover layer was launched in 1997 with the participation of the French uranium mining company (COGEMA). Evaluation of the cover layer's effectiveness in reducing 222Rn flux emanating from UMTs was one of its objectives. In the first phase, the 222Rn flux densities were measured regularly on a UMT layer. In the second phase, the UMT was covered with a one-meter layer of compacted material consisting of crushed waste rock derived from mining activities. Radon-222 flux was then measured at the surface of this cover layer. Observations were compared with radon flux calculated using TRACI, a model for vertical water and gas flow and radon transport. The results show that the calculations bear a fair resemblance to the observations in both cases. They also show that the effectiveness of the cover layer calculated with TRACI, using the thickness and textural properties of the cover material, is very close to the measured effectiveness. 相似文献
545.
Mapping the probability of exceeding critical thresholds for cadmium concentrations in soils in The Netherlands 总被引:3,自引:0,他引:3
Brus DJ de Gruijter JJ Walvoort DJ de Vries F Bronswijk JJ Römkens PF de Vries W 《Journal of environmental quality》2002,31(6):1875-1884
The probability of exceeding critical thresholds of Cd concentrations in the soil was mapped at a national scale. The critical thresholds in soil were based on food quality criteria for Cd in crops or in organs of cattle (Bos taurus), and were calculated by inverting a regression model for the Cd concentration in the crop, with the Cd concentration in soil, soil organic matter (SOM) content, clay content, and pH as predictors. The probability of exceeding the critical threshold for Cd in soil per node of a 500- x 500-m grid was approximated by Monte Carlo simulation, using the estimated cumulative distribution functions (cdf) of SOM, clay, pH, and Cd as input. The cdfs were estimated by simple indicator kriging with local prior means. For SOM, clay, and pH, detailed maps of soil type and land use were used to define subregions with assumed constant local means of the indicators (a priori distributions). The cdfs were sampled by Latin hypercube sampling. We accounted for correlation between the actual and critical Cd concentrations in soil by drawing Cd values from cdfs conditional on SOM and clay. The estimated probability for grassland is negligible, even in areas with high Cd concentrations in soil, and for maize (Zea mays L.) land the probability is almost everywhere smaller than 5%. For arable soils, however, these probabilities commonly are larger than 5% when sugar beet (Beta vulgaris L.) or wheat (Triticum aestivum L.) is taken as a reference crop, and locally exceed 50%. 相似文献
546.
Van Hulle M De Cremer K Cornelis R Lameire N 《Journal of environmental monitoring : JEM》2001,3(1):86-90
Five Wistar rats were given an intraperitoneal injection of [114mIn]InCl3 during four consecutive days. One hour after the last injection the rats were sacrificed. The in vivo distribution of 114mIn was studied in the blood and in different organs. Differential centrifugation was used to study the distribution in liver, kidney and spleen homogenate. Rat serum, packed cell lysate, urine and the cytosol of liver, kidney and spleen homogenate were examined by size exclusion fast protein liquid chromatography. The results showed that serum accounts for 90% of the indium activity in whole blood. Indium is preferentially accumulated within the liver, spleen and kidney, the highest amount of 114mIn being localised in the cytosolic fraction followed by the mitochondria. Size exclusion experiments showed that, in rat serum, indium is exclusively bound to transferrin. These results differed from earlier in vitro incubation experiments of human serum with 114mIn. It was not possible, from the experiments described herein, to conclude unequivocally whether indium is bound to haemoglobin of packed cell lysate or to another high molecular mass compound. Indium is associated with the high molecular mass fraction in liver, kidney and spleen cytosol; only in kidney are small amounts of 114mIn found in the low molecular mass fraction. The in vivo inhibitory effect of indium on the delta-aminolaevulinic acid dehydratase (ALAD) enzymatic activity in red blood cells and kidney tissue, well documented by other researchers, could not be attributed to direct binding of indium with this enzyme. 相似文献
547.
对武钢一管式炉2000年3月24日发生煤气爆燃事故进行了分析,结合管式炉周围现场情况,提出了避免此类事故再发生的防范措施。 相似文献
548.
549.
Past research has revealed that team effectiveness and satisfaction suffer when teams experience relationship conflict—conflict related to interpersonal issues, political norms and values, and personal taste. This study examined how teams should respond to these conflicts. Three types of conflict responses were studied: collaborating responses, contending responses, and avoiding responses. A field study involving a heterogeneous sample of teams performing complex, non‐routine task showed that collaborating and contending responses to relationship conflict negatively relate to team functioning (i.e., voice, compliance, helping behavior) and overall team effectiveness, while avoiding responses were associated with high team functioning and effectiveness. It is suggested that collaborating and contending responses to relationship conflict distract team members from their tasks, while avoiding responses appear more functional in that they allow team members to pursue task performance. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
550.
Metacommunity structure of pond macroinvertebrates: effects of dispersal mode and generation time 总被引:1,自引:0,他引:1
A recent challenge in community ecology is to understand under what conditions local and regional processes may be more important in shaping community structure. We investigated the role of dispersal mode and generation time for communities of macroinvertebrates in two sets of connected ponds during three consecutive years. We found no evidence that generation time affected metacommunity structure, possibly because statistical power was limited because the range of generation times present was small. In contrast, we found that the spatial structure of the macroinvertebrate metacommunities differed with dispersal mode in one of two sets of ponds. Passive dispersers showed positive distance-dissimilarity correlations, suggesting mass effects via the pond connections. These correlations did not stretch beyond the first pond downstream suggesting that, in this chain of connected ponds, intervening ponds effectively buffered dispersal. Active dispersers did not show any consistent spatial pattern, possibly because intensive over-land dispersal homogenized the metacommunity. Thus, although pond connections probably equally promoted dispersal of actively and passively dispersing macroinvertebrates, the implications for the structure of their metacommunities may depend on their dispersal mode. We conclude that dispersal mode has the potential to affect the mechanisms that are integral to metacommunity structure. 相似文献