全文获取类型
收费全文 | 15757篇 |
免费 | 1006篇 |
国内免费 | 2336篇 |
专业分类
安全科学 | 2340篇 |
废物处理 | 167篇 |
环保管理 | 2257篇 |
综合类 | 8213篇 |
基础理论 | 1657篇 |
环境理论 | 11篇 |
污染及防治 | 1183篇 |
评价与监测 | 823篇 |
社会与环境 | 1440篇 |
灾害及防治 | 1008篇 |
出版年
2024年 | 49篇 |
2023年 | 225篇 |
2022年 | 373篇 |
2021年 | 469篇 |
2020年 | 439篇 |
2019年 | 393篇 |
2018年 | 347篇 |
2017年 | 497篇 |
2016年 | 602篇 |
2015年 | 612篇 |
2014年 | 638篇 |
2013年 | 802篇 |
2012年 | 1031篇 |
2011年 | 1167篇 |
2010年 | 854篇 |
2009年 | 851篇 |
2008年 | 696篇 |
2007年 | 1063篇 |
2006年 | 1085篇 |
2005年 | 873篇 |
2004年 | 733篇 |
2003年 | 834篇 |
2002年 | 670篇 |
2001年 | 564篇 |
2000年 | 514篇 |
1999年 | 506篇 |
1998年 | 384篇 |
1997年 | 303篇 |
1996年 | 252篇 |
1995年 | 230篇 |
1994年 | 231篇 |
1993年 | 194篇 |
1992年 | 152篇 |
1991年 | 115篇 |
1990年 | 79篇 |
1989年 | 45篇 |
1988年 | 41篇 |
1987年 | 19篇 |
1986年 | 19篇 |
1985年 | 29篇 |
1984年 | 14篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1977年 | 11篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
We exploit recent advances in climate science to develop a physically consistent, yet surprisingly simple, model of climate policy. It seems that key economic models have greatly overestimated the delay between carbon emissions and warming, and ignored the saturation of carbon sinks that takes place when the atmospheric concentration of carbon dioxide rises. This has important implications for climate policy. If carbon emissions are abated, damages are avoided almost immediately. Therefore it is optimal to reduce emissions significantly in the near term and bring about a slow transition to optimal peak warming, even if optimal steady-state/peak warming is high. The optimal carbon price should start relatively high and grow relatively fast. 相似文献
962.
963.
964.
新疆阿舍勒块状铜锌硫化物矿床在阿尔泰克兰海西褶皱带玛尔卡库里深断裂的东北侧,产于中泥盆统阿舍勒组英安岩及英安质火山碎屑岩中,与次火山岩关系密切,矿床具有明显的分带性。矿体下盘矿化和围岩蚀变强烈。认为是与海底火山作用有关的黑矿型块状铜锌硫化物矿床。 相似文献
965.
西江沿岸地带是一个工业不发达的待开发民族区域,但它拥有多方面工业资源优势,而且工业开发环境条件良好。作者认为,优势的工业资源开发必须在全方位开放与资源深度利用的基础上以轻型为主导的策略,重点建设制糖、水果加工、水电、有色金属为主的原材料及加工等若干工业基地。布局上以西江干流和区内铁路干线为“轴”,结合重点工业“点”,稳定提高中部,重点开发东部,创造条件开发西部,实现“点轴结合,逐步推进”的工业资源区域开发策略。 相似文献
966.
First-trimester prenatal diagnosis of a fetus at 25 per cent risk for cystic fibrosis (CF) was performed by indirect linkage analysis of polymorphic markers using Southern blotting and polymerase chain reaction (PCR) amplification. The results revealed discrepancies in the allelic patterns between the father and the affected child, thereby complicating the prediction of fetal outcome. Analysis of a highly polymorphic VNTR locus within the human retinoblas-toma (RB) gene on chromosome 13 showed that the affected child and the fetus did not have the same biological father, and therefore the affected child could not be used to determine linkage of markers in the father of the fetus. The analysis of VNTR loci can be an effective method of resolving conflicting data during prenatal diagnosis of monogenic diseases. 相似文献
967.
Yanying Bai Weiping Chen Andrew C. Chang Albert L. Page 《Journal of environmental science and health. Part. B》2013,48(6):531-539
Potentially hazardous trace elements such as Cd, Cu, Cr, Ni and Zn are expected to accumulate in biosolids–amended soil and remain in the soil for a long period of time. In this research, uptake of metals by food plants including cabbage, carrot, lettuce and tomato grown on soils 10 years after biosolids application was studied. All the five metals were significantly accumulated in the biosolids-amended soils. The accumulation of metal in soil did not result in significant increase in concentrations of Cu, Cr and Ni in the edible plant tissues. However, the Cd and Zn concentrations of the edible tissues of plants harvested from the biosolids receiving soils were significantly enhanced in comparison with those of the unaffected soils. The plant uptake under Greenfield sandy loam soil was generally higher than those under the Domino clayey loam soil. The metal concentration of edible plant tissue exhibited increasing trends with respect to the concentrations of the ambulated metals. The extents of the increases were plant species dependent. The indigenous soil metals were absorbed by the plants in much higher rates than those of the biosolids–receiving soils. It appeared that the plant uptake of the indigenous soil-borne metal and the added biosolids-borne metals are independent of one another and mathematically are additive. 相似文献
968.
Ali Fanous Michael Hecker Angelika Görg Harun Parlar Fritz Jacob 《Journal of environmental science and health. Part. B》2013,48(7):666-675
Cobalt and silver are toxic for cells, but mechanisms of this toxicity are largely unknown. Analysis of Corynebacterium glutamicum proteome from cells grown in control and cobalt or silver enriched media was performed by two dimensional gel electrophoresis (2DE) followed by mass spectrometry. Our results indicate that the cell adapted to cobalt stress by inducing five defense mechanisms: Scavenging of free radicals, promotion of the generation of energy, reparation of DNA, reparation and biogenesis of Fe-S cluster proteins and supporting and reparation of cell wall. In response to the detoxification of Ag+ many proteins were up-regulated, which involved reparation of damaged DNA, minimizing the toxic effect of reactive oxygen species (ROS) and energy generation. Overexpression of proteins involved in cell wall biosynthesis (1,4-alpha-glucan branching enzyme and nucleoside-diphosphate-sugar epimerase) upon cobalt stress and induction of proteins involved in energy metabolism (2-methylcitrate dehydratase and 1, 2-methylcitrate synthase) upon silver demonstrate the potential of these enzymes as biomarkers of sub-lethal Ag+ and Co toxicity. 相似文献
969.
Makkimane B. Nataraj Sannanegunda V. Krishnamurthy 《Journal of environmental science and health. Part. B》2013,48(2):67-73
This study was undertaken to determine the effect of environmentally realistic concentrations of two commonly used pesticides viz., malathion and cypermethrin, using a fully 3 × 3 factorial experiments on the survivability and time of metamorphosis in a common rice paddy field frog (cricket frog) Fejervarya limnocharis under laboratory conditions. The results suggest that cypermethrin is more toxic than malathion and combinations of higher concentrations of cypermethrin (50 μg/L) with malathion (250 and 500 μg/L) are more deleterious to the survivability of tadpoles. With increasing cypermethrin concentration, the survivability of tadpole decreased (r = ?0.986, P = 0.108). But cypermethrin alone induced early metamorphosis among the surviving tadpoles. However, there was a delay in the time required for metamorphosis induced by malathion and its combination with cypermethrin. The delay in metamorphosis may indicate the altered physiological fitness of the individual. The emergent froglets will be subjected to environmental stressors like high temperature and less humidity of post-monsoon tropical climate that could enhance negative influence triggered by pesticides. 相似文献
970.
Zsuzsanna Horváth Árpád Ambrus László Mészáros Simone Braun 《Journal of environmental science and health. Part. B》2013,48(8):615-625
The characteristic features of distribution of pesticide residues in crop units and single sample increments were studied based on more than 19,000 residue concentrations measured in root vegetables, leafy vegetables, small-, medium- and large-size fruits representing 20 different crops and 46 pesticides. Log-normal, gamma and Weibull distributions were found to provide the best fit for the relative frequency distributions of individual residue data sets. The overall best fit was provided by lognormal distribution. The relative standard deviation of residues (CV) in various crops ranged from 15–170%. The 100–120 residue values being in one data set was too small to identify potential effects of various factors such as the chemical and physical properties of pesticides and the nature of crops. Therefore, the average of CV values, obtained from individual data sets, were calculated and considered to be the best estimate for the likely variability of unit crop residues for treated field (CV = 0.8) and market samples (CV = 1.1), respectively. The larger variation of residues in market samples was attributed to the potential mixing of lots and varying proportion of non-detects. The expectable average variability of residues in composited samples can be calculated from the typical values taking into account the sample size. 相似文献