全文获取类型
收费全文 | 4744篇 |
免费 | 551篇 |
国内免费 | 1859篇 |
专业分类
安全科学 | 610篇 |
废物处理 | 208篇 |
环保管理 | 428篇 |
综合类 | 3430篇 |
基础理论 | 735篇 |
污染及防治 | 950篇 |
评价与监测 | 286篇 |
社会与环境 | 306篇 |
灾害及防治 | 201篇 |
出版年
2024年 | 28篇 |
2023年 | 128篇 |
2022年 | 339篇 |
2021年 | 319篇 |
2020年 | 354篇 |
2019年 | 271篇 |
2018年 | 278篇 |
2017年 | 320篇 |
2016年 | 260篇 |
2015年 | 367篇 |
2014年 | 439篇 |
2013年 | 480篇 |
2012年 | 491篇 |
2011年 | 458篇 |
2010年 | 409篇 |
2009年 | 342篇 |
2008年 | 360篇 |
2007年 | 312篇 |
2006年 | 250篇 |
2005年 | 160篇 |
2004年 | 113篇 |
2003年 | 83篇 |
2002年 | 105篇 |
2001年 | 98篇 |
2000年 | 49篇 |
1999年 | 60篇 |
1998年 | 45篇 |
1997年 | 44篇 |
1996年 | 36篇 |
1995年 | 31篇 |
1994年 | 27篇 |
1993年 | 28篇 |
1992年 | 26篇 |
1991年 | 12篇 |
1990年 | 2篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有7154条查询结果,搜索用时 46 毫秒
831.
832.
833.
834.
An overview of the spatial and temporal variations of the environmental accidents in China in recent years was presented in
this paper using available data. The results showed that the frequency of pollution accidents was significantly decreased,
from 3462 in 1990 to 462 in 2007. The water and air pollution accidents were found to be the dominant types, accounting for
more than 80% of the total accidents. Considering the classification of environmental accidents at 4 scales, the general environmental
accident, i.e., the least serious type, was the most frequent event, taking up 58.98% of the total pollution accidents. In
addition, the distribution of environmental accidents was generally in accordance with the industrial layout in the country
during the past decade. It is very important to note that the extraordinarily severe environmental accidents showed an increasing
trend in underdeveloped regions, which was caused by the transfer and the development of heavy polluted industry in these
areas. As to the losses of environmental accidents, the casualties presented an obvious reduction tendency, while the direct
economic loss per accident tended to climb up. Furthermore, some key factors that affect the spatial and temporal tendencies
of environmental accidents in China were discussed and some suggestions were put forward, hoping to shed light on environmental
risk management and emergency plans making associated with environmental accidents in China. 相似文献
835.
鉴于目前国内大多数图书馆尚未建立计算机检索专业文献系统,本文介绍了国内外常用的检索环境科学文献资料的工具书,论述了手工检索科技文献资料的方法和步骤.为科技工作者查阅有关国内外科技文献资料提供参考. 相似文献
836.
固定化硝化菌去除氨氮的研究 总被引:48,自引:4,他引:44
选用氯乙烯醇作为包埋载体,添加适量粉末活性炭,包埋固定硝化污泥,处理以(NH4)2SO4和葡萄糖为主的合成废水,考察了影响固定化工艺及硝化作用的各种因素。对固定化硝化菌的呼吸活性,细菌活性回收率等生物特性进行了测定。 相似文献
837.
838.
采用体内试验和体外试验方法,观察氯化镉对小鼠免疫功能的影响。免疫后不同时间,给小鼠一次灌胃30mg/kgCdCl2,未见对免疫功能产生明显影响。反复多次灌胃染毒14天,在0.3mg/ks/d组可见明显抑制小鼠脾淋巴细胞IgM-pFC,抑制率为42.1%。体外试验表明,12.5μmol/LCdCl2与淋巴细胞作用48h,25μmol/LCdCl2作用72h,对淋巴细胞增殖反应抑制率分别为38.3%和77.8%,以上结果表明氟化钢具有明显的免疫毒性。 相似文献
839.
In order to evaluate the ecological hazard of 4-tert-butylphenol (4-TBP), species abundances and physicochemical properties were monitored for 63 days in a microcosm system containing planktonic algae, rotifers, shrimps and Daphnia. The 63 days-NOEC (no observed effect concentration) of 4-TBP for this system was calculated. At the same time, species sensitivity distribution curves were constructed based on the toxicity data of EC10, EC50 and NOEC derived from laboratory single-species toxicity tests, which further gives no obvious hazard concentrations for 95% species in the ecosystem (HC5). In both the microcosm and the single-species tests, the shrimp (Neocaridina sp.) was the most sensitive species to 4-TBP exposure, while most algae species were relatively insensitive compared to the zooplankton. For the microcosm exposed to 4-TBP, significant changes occurred to the community structure instead of the community function, resulting in a NOECmicrocosm of 265.38?μg?L–1 which approached the EC10-based HC5 (0.376?mg?L–1). Nevertheless, EC50-based HC5 was higher than the NOECmicrocosm, and the NOEC-based HC5 was lower. The data showed that the EC10-based HC5 was protective at the similar level with the result of microcosm for 4-TBP, providing supportive data for chemical risk assessment. 相似文献
840.