全文获取类型
收费全文 | 2810篇 |
免费 | 313篇 |
国内免费 | 848篇 |
专业分类
安全科学 | 556篇 |
废物处理 | 71篇 |
环保管理 | 388篇 |
综合类 | 1885篇 |
基础理论 | 337篇 |
污染及防治 | 256篇 |
评价与监测 | 73篇 |
社会与环境 | 234篇 |
灾害及防治 | 171篇 |
出版年
2024年 | 24篇 |
2023年 | 93篇 |
2022年 | 137篇 |
2021年 | 164篇 |
2020年 | 145篇 |
2019年 | 132篇 |
2018年 | 90篇 |
2017年 | 109篇 |
2016年 | 144篇 |
2015年 | 145篇 |
2014年 | 156篇 |
2013年 | 220篇 |
2012年 | 259篇 |
2011年 | 267篇 |
2010年 | 187篇 |
2009年 | 171篇 |
2008年 | 150篇 |
2007年 | 252篇 |
2006年 | 204篇 |
2005年 | 155篇 |
2004年 | 126篇 |
2003年 | 110篇 |
2002年 | 105篇 |
2001年 | 78篇 |
2000年 | 80篇 |
1999年 | 51篇 |
1998年 | 51篇 |
1997年 | 37篇 |
1996年 | 28篇 |
1995年 | 22篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 14篇 |
1991年 | 3篇 |
1990年 | 9篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3971条查询结果,搜索用时 31 毫秒
31.
在市场经济条件下,对符合法定条件的排污许可证应当允许其有偿转让。可转让的排污许可证必须以污染物申报登记为基础,以污染物总量控制为前提,以环境标准为依据,转让活动应当在政府严格监督下进行。可转让排污许可证制度通过市场机制和价值规律必将有效地促进污染防治。 相似文献
32.
33.
Counselling in connection with prenatal diagnosis (PND) is a common task for the obstetrician and the midwife. However, the decision making processes of pregnant women are not completely known, for instance, the questions of women's autonomy, the decision on how to act in the case of an abnormal test, and the partner's participation in the decision. A questionnaire and interview study was carried out among 211 women undergoing PND by amniocentesis or chorionic villus biopsy. Most women in the sample indicated that PND was completely voluntary. However, at the same time almost every woman reported that it was difficult to decline from PND when offered. Even before the visit to register at the antenatal clinic, most of the women (83 per cent) had made up their minds to have PND. At the time of the test, many of the participants (62 per cent) had decided in favour of a legal abortion if the test indicated an abnormality in the fetus. At the same time, however, the data indicate a need for reflection and ambivalence, which the medical staff have to accept. In the questionnaire most of the women stated that they and their partners had similar attitudes towards PND, but when interviewed 38 per cent of the women admitted some differences between their own attitudes and their partners'. Although some women reported considerable deliberation and ambivalence, most of them said that they would undergo PND in another pregnancy. 相似文献
34.
35.
In this paper,the relationship among land productivity,population pressure and the fluctuation mechanism of ecotone is analyzed,taking coumties and banners of southeast Inner Mongolia plateau as an example,which is the most fragile part in the farming and husbandry interleaving belt of north China due to its severe desertification degree and low level of economic development.The Cv for the total output value of agriculture decreases from southeast to northwest,with the same rule as which the overloading population cumulated distributes,and both indicators have close relation with the high linear coefficient of 0.83.These reveal the fluctuation mechanism for ecotone:fluctuation of the level of economic development is a scientific and practical measure both to weakness degree and to instability of ecotone,because it is a synthesized response to the variation of climate as well as irrational land uses,which reinforce and magnify the fluctuation.In detail,the heavier the population overloading,the severer the grassland reclamation,the stronger the dependence of regional productivity on rainfall,the lower the level of economic development,the rougher the fluctuation of ecotone,but the weaker the PRED system. 相似文献
36.
宋延军 《防灾科技学院学报》2006,8(4):94-97
高等院校管理者必须思考如何更加有效的激励教师工作的积极性。高等院校教师的有效激励机制包括教师工作激励机制、教师成就激励机制和优秀教师的价值激励机制。三者有机结合,才能更好的促进教师的工作积极性、主动性、创造性,实现高等院校教师的自我价值。 相似文献
37.
很多学生现在对英语学习感到无所适从,他们觉得自己无论如何尽力也没有办法提高英语成绩。本文对这种情况的出现做了简单的分析,并提出了一些建议。 相似文献
38.
39.
40.
曾庆平 《防灾科技学院学报》2005,7(3):48-52
本文对地震台站在新时期的台站管理进行了论述。指出在防震减灾基础建设的重要时期,地震台站的管理,首先需要转变管理理念,同时应完善组织结构建设,建立激励机制。这是完成中国地震局确定的《与时俱进、开拓创新,为全面实现地震台站的现代化而奋斗》重要工作之一。 相似文献