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排序方式: 共有332条查询结果,搜索用时 15 毫秒
291.
防弹衣的服用发展趋势 总被引:1,自引:0,他引:1
目前,防弹衣作为一种重要的防护装备,虽然其防弹性能已经得到了较大的提高,但其对使用者的活动和穿着舒适性有较大的限制和影响。因此,对防弹衣减重和舒适性的研究相当迫切。本文对国内外的防弹衣研究进展情况进行了介绍,并对防弹衣减重及舒适性发展的研究和未来趋势进行了探讨。 相似文献
292.
Rongrong Xie Yong Pang Zhe Li Ninghong Zhang Fenjuan Hu 《Environmental management》2013,51(4):874-881
Eco-compensation is a multi-disciplinary topic. There is no consensus on the issue of river eco-compensation across districts. Although policies regarding river eco-compensation have been issued in China since 2008, due to the high cost, eco-compensation has not been well implemented in the Taihu pilot region. Therefore, a simplified method based solely on water quality (both water quality and water volume included in the Taihu method) was proposed for North Jiangsu province (NJP). However, the formula was flawed and it led to payments being too low. Three problems need to be solved: (1) how to specify the eco-compensation areas; (2) how to test a reasonable eco-compensation model and (3) how to determine the compensation criterion. Solving these issues is already a priority. In this paper, three potential solutions surrounding eco-compensation are discussed: (1) three principles for selecting the representative eco-compensation areas are suggested; (2) the compensation calculation method based on contaminant flux above the ultra standard is revised and (3) a compensation criterion model based on the treatment costs of sewage is proposed. In the NJP case in 2009, the average eco-compensation criterion for chemical oxygen demand (COD) is 2,000 Chinese Yuan (CNY) per ton and ammonia nitrogen (NH4–N) and total phosphorus (TP) are 8,000 CNY and 80,000 CNY per ton, respectively. Five districts needed to be compensated. The payments in the revised scheme were 4.15–586 million CNY, which were 16–48 times greater than that in the draft method. The new method can provide an important template for managers when drafting river eco-compensation schemes. 相似文献
293.
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295.
Zhaozhong Feng Jing Pang Isamu Nouchi Takashi Yamakawa 《Environmental pollution (Barking, Essex : 1987)》2010,158(12):3539-3545
We studied leaf apoplastic ascorbates in relation to ozone (O3) sensitivity in two winter wheat (Triticum aestivum L.) varieties: Yangfumai 2 (Y2) and Yangmai 16 (Y16). The plants were exposed to elevated O3 concentration 27% higher than the ambient O3 concentration in a fully open-air field from tillering stage until final maturity. The less sensitive variety Y16 had higher concentration of reduced ascorbate in the apoplast and leaf tissue by 33.5% and 12.0%, respectively, than those in the more sensitive variety Y2, whereas no varietal difference was detected in the decline of reduced ascorbate concentration in response to elevated O3. No effects of O3 or variety were detected in either oxidized ascorbate or the redox state of ascorbate in the apoplast and leaf tissue. The lower ascorbate concentrations in both apoplast and leaf tissue should have contributed to the higher O3 sensitivity in variety Y2. 相似文献
296.
Wang MC Gong M Zang HB Hua XM Yao J Pang YJ Yang YH 《Journal of environmental science and health. Part. B》2006,41(4):399-413
In this study, we evaluated the effect of the application by two agrochemicals, methamidophos (O,S-dimethyl phosphoroamidothioate) and urea, on microbial diversity in soil, using the combined approaches of soil microbial biomass analysis and community level physiological profiles (CLPPs). The results showed that both a low and a high level of methamidophos application (CS2 and CS3) and urea application (CS4) significantly decreased microbial biomass C (Cmic) by 41-83% compared with the control (CS1). The soil organic C (Corg) values of CS3 and CS4 were significantly higher and lower by 24% and 14%, respectively, than that of CS1. Similarly to Cmic, the values of Cmic/Corg of the three applied soils which decreased were lower by 31-84% than that of CS1. In contrast, the respiration activity of the three applied soils were significantly higher than the control. Agrochemical application also significantly increased the soil total of N and P (Ntol and Ptol) and decreased the Corg/Ntol and Corg/Ptol values. The CLPPs results showed that the AWCD (average well color development) of the three applied soils were significantly higher than that of CS1 during the incubation period. Substrate richness, Shannon and Simpson indices of microbial communities under chemical stresses, increased significantly. In addition, the CFU (colony-forming unit) numbers of methamidophos metabolized bacteria in CS2 and CS3 also increased significantly by 86.1% and 188.9% compared with that of CS1. The combined results suggest that agrochemicals reduce microbial biomass and enhance functional diversities of soil microbial communities; meanwhile, some species of bacteria may be enriched in soils under methamidophos stress. 相似文献
297.
The occurrence of tributyltin (TBT) is reported in the coastal waters of a few selected sites in Peninsular Malaysia. Water, bivalves and sediment samples collected were analysed specifically for TBT using sensitive analytical methods which involved a solvent extraction procedure with appropriate clean-up followed by graphite furnace atomic absorption spectrometric measurements. The levels of TBT in the seawater in unexposed areas were found in the range from <3.4 to 20 ng litre(-1) as compared to coastal areas with high boat and ship activities where TBT levels in seawater were generally above 30 ng litre(-1), with the highest level found at 281.8 ng litre(-1). TBT levels in the tissues of random cockle and soft-shell clam samples from local markets were found in the range from <0.5 to 3.7 ng g(-1) wet weight. The levels of TBT found in green mussel samples both from the market (23.5 ng g(-1) wet weight) and those from a mussel farm (14.2 ng g(-1) wet weight) indicate slight accumulation of TBT. In sediments, TBT levels were found ranging from <0.7 ng g(-1) dry weight in unexposed coastal sites to as high as 216.5 ng g(-1) dry weight for a site within a port area. 相似文献
298.
爿 J。1、仆;。。、。。——上。八。。。〕。。。-。;。、一、。h川D{、例I;-J二卜;H。。。比;/’-v;卜,-,。。,’.二,川。{.、-。一。。卜。;。 一、一、,川。…-八卜、!。八。」、阶*。H 一。。,-;、,。、,一一;。人I厂、。、,叫U山小uV。。。‘5、;山o.7‘。)3。t竹’Zgl。5,f\.卜5川厂l。。厂;…。j。。531,-。I。/。-:。--,t勺3、。5<比 卜,小y、。二L洲H几,。-“。丫 口、川\一、.’.一、一、,卜-一、。们厂… 相似文献
299.
太湖水底摩擦系数的估算 总被引:1,自引:0,他引:1
利用1992年8月至1992年10月在太湖马山地区测得的风,浪资料,采用浅水浪公式对太湖水底摩擦系数进行了估算,估算值为0.0025。 相似文献
300.
汞、DDT、六六六在蓟运河河口生态系中的迁移、积累与循环 总被引:4,自引:1,他引:4
在蓟运河河口生态系统中,水生生物对汞、DDT、六六六均有很强的积累能力,体内积累量大体上有沿生物营养等级而增高的趋势,尤以汞最为明显。汞在浮游生物、底栖动物、草食性鱼类、杂食性鱼类、肉食性鱼类及水鸟体内的平均含量分别为0.34、0.48、0.90、1.28、1.70和3.29mg/kg。 六六六的浓缩因子较小(10~2),且易于排出;DDT的积累能力最强(10~4),但在生物体内易转化成毒性较小的DDE和DDD;汞有较强的富集能力(10~3),可在生态系统中循环住复。 相似文献