全文获取类型
收费全文 | 21701篇 |
免费 | 283篇 |
国内免费 | 1594篇 |
专业分类
安全科学 | 721篇 |
废物处理 | 954篇 |
环保管理 | 2791篇 |
综合类 | 4283篇 |
基础理论 | 5465篇 |
环境理论 | 5篇 |
污染及防治 | 6815篇 |
评价与监测 | 1304篇 |
社会与环境 | 956篇 |
灾害及防治 | 284篇 |
出版年
2023年 | 143篇 |
2022年 | 305篇 |
2021年 | 282篇 |
2020年 | 193篇 |
2019年 | 227篇 |
2018年 | 386篇 |
2017年 | 402篇 |
2016年 | 604篇 |
2015年 | 585篇 |
2014年 | 805篇 |
2013年 | 1891篇 |
2012年 | 915篇 |
2011年 | 1070篇 |
2010年 | 836篇 |
2009年 | 976篇 |
2008年 | 1081篇 |
2007年 | 1089篇 |
2006年 | 961篇 |
2005年 | 782篇 |
2004年 | 768篇 |
2003年 | 751篇 |
2002年 | 732篇 |
2001年 | 855篇 |
2000年 | 669篇 |
1999年 | 437篇 |
1998年 | 374篇 |
1997年 | 303篇 |
1996年 | 343篇 |
1995年 | 338篇 |
1994年 | 312篇 |
1993年 | 282篇 |
1992年 | 252篇 |
1991年 | 200篇 |
1990年 | 223篇 |
1989年 | 200篇 |
1988年 | 192篇 |
1987年 | 175篇 |
1986年 | 154篇 |
1985年 | 148篇 |
1984年 | 178篇 |
1983年 | 175篇 |
1982年 | 168篇 |
1981年 | 174篇 |
1980年 | 136篇 |
1979年 | 159篇 |
1978年 | 108篇 |
1977年 | 102篇 |
1975年 | 95篇 |
1973年 | 92篇 |
1972年 | 100篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
221.
222.
Sui Pengzhe Wen Xianghua Huang Xia 《Frontiers of Environmental Science & Engineering in China》2007,1(3):362-367
In this study, ultrasound was used to control the membrane fouling online in an anaerobic membrane bioreactor (AMBR). Short-term
running experiments were carried out under different operating conditions to explore feasible ultrasonic parameters. The experimental
results indicated that when the crossflow velocity was more than 1.0 m/s, membrane fouling could be controlled effectively
only by hydrodynamic methods without ultrasound. When ultrasound was applied, an ultrasonic power range of 60–150 W was suitable
for the membrane fouling control in the experimental system. The experimental results showed that the membrane fouling was
controlled so well that membrane filtration resistance (ΣR) could stay at 5 × 1011 m−1 for more than a week with the crossflow velocity of 0.75 m/s, which equaled the effect of crossflow velocity of more than
1.0 m/s without ultrasound.
Translated from Techniques and Equipment for Environmental Pollution Control, 2006, 7(4): 25–29 [译自: 环境污染治理技术与设备] 相似文献
223.
通过对一个待建的城市生活垃圾场处理技术的综合分析,建立一个相对完整的指标体系,然后用模糊数学的方法,对指标体系进行量化、归一化,得到一个通用的评价模型,并运用此模型对该垃圾的垃圾处理方式进行评价,最后提出卫生填埋是当前较为合理的处理方式。 相似文献
224.
曲霉对水中重金属的吸附去除 总被引:15,自引:0,他引:15
利用2种曲霉A.sojae M146和A.oryzae M149的菌体,作为吸附剂对水中Pb^2+和Cd^2 进行去除实验。结果表明,曲霉菌体的最佳培养时间为72h,吸附的最佳pH为5.5、温度为30℃、时间为1h。在最佳实验条件下,A.sojae M146对Pb^2 和Cd^2 的吸附率,分别为69.76%和72.28%;A.oryzae M149对Pb^2 和Cd^2 的吸附率,分别为60.64%和81.34%。使用稀碱溶液对曲霉菌体进行浸泡预处理后,可提高对重金属的吸附去除效果;而使用稀释、乙醇水溶液以及蒸馏水对菌体浸泡后,明显降低了重金属的去除效果。Na2CO3和EDTA溶液,可以有效地将重金属从曲霉体上解吸下来,从而达到重复利用菌体作为吸附剂的目的。 相似文献
225.
226.
227.
228.
Emanuela Terzian Jillian Boreham Howard S. Cuckle Nicholas J. Wald Martin Bobrow Richard Lindenbaum A. C. Turnbull 《黑龙江环境通报》1985,5(6):401-414
A survey was conducted of the results of mid-trimester diagnostic amniocenteses in the Oxford Region from 1974 to 1981. The survey used data relating to all 4357 singleton pregnancies in which an amniocentesis was performed during this period. Follow-up information on outcome was obtained in respect of 4284 (98 per cent) pregnancies. A cell culture to determine karyotype and an alpha-fetoprotein determination was carried out in all cases. From 1974 to 1981 amniocenteses became increasingly common, rising from 2 to 32 per 1000 births. The most common indication for amniocentesis was a high risk of a chromosome abnormality–56 per cent of all amniocenteses. Within this group advanced maternal age was responsible for 89 per cent of the cases. The next most common indication was a high risk of a neural tube defect (37 per cent of all amniocenteses)–in 1974 a raised maternal serum alpha-fetoprotein level accounted for only 4 per cent of these; by 1981 this had risen to 67 per cent. There were seven false-positive and 132 true-positive diagnoses of neural tube defect; since 1981, with the introduction of amniotic fluid acetylocholinesterase determination as a secondary diagnostic test for neural tube defects, there have been no further false-positive diagnoses. In 1981 76 per cent of women aged 35 years or more did not have an amniocentesis. It is not known to what extent this was due to not offering women in this age group amniocentesis or to women not accepting such an offer. 相似文献
229.
Hurler's disease was excluded in a fetus at 23 weeks' gestation by demonstrating normal iduronidase activity in fetal leucocytes following failure of amniotic cell culture after amnic-centesis at 16 and 19 weeks' gestation. The diagnosis was confirmed in the neonate. 相似文献
230.