全文获取类型
收费全文 | 7062篇 |
免费 | 211篇 |
国内免费 | 1834篇 |
专业分类
安全科学 | 325篇 |
废物处理 | 441篇 |
环保管理 | 576篇 |
综合类 | 2899篇 |
基础理论 | 1799篇 |
环境理论 | 1篇 |
污染及防治 | 2215篇 |
评价与监测 | 368篇 |
社会与环境 | 296篇 |
灾害及防治 | 187篇 |
出版年
2024年 | 6篇 |
2023年 | 72篇 |
2022年 | 194篇 |
2021年 | 179篇 |
2020年 | 154篇 |
2019年 | 113篇 |
2018年 | 255篇 |
2017年 | 325篇 |
2016年 | 396篇 |
2015年 | 344篇 |
2014年 | 314篇 |
2013年 | 469篇 |
2012年 | 795篇 |
2011年 | 584篇 |
2010年 | 319篇 |
2009年 | 334篇 |
2008年 | 364篇 |
2007年 | 329篇 |
2006年 | 297篇 |
2005年 | 571篇 |
2004年 | 644篇 |
2003年 | 553篇 |
2002年 | 202篇 |
2001年 | 139篇 |
2000年 | 138篇 |
1999年 | 177篇 |
1998年 | 127篇 |
1997年 | 126篇 |
1996年 | 110篇 |
1995年 | 125篇 |
1994年 | 88篇 |
1993年 | 74篇 |
1992年 | 54篇 |
1991年 | 42篇 |
1990年 | 19篇 |
1989年 | 11篇 |
1988年 | 17篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1961年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有9107条查询结果,搜索用时 16 毫秒
1.
2.
3.
Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder. 相似文献
4.
本文对某铀矿职业工人和非职业工人头发中的总β、总α放射性水平和铀、钍含量进行了分析测定.结果表明,该矿工人体内铀和钍的蓄积量均在正常放射性本底水平范围内,从头发中检验未观察到工人体内铀、钍放射性水平有明显的升高. 相似文献
5.
The modern theory of biological evolution: an expanded synthesis 总被引:12,自引:2,他引:12
In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwins Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwins perspective. Weismanns neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwins dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the modern synthesis is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer open-ended questions concerning the mechanisms of evolution in all five kingdoms of life.Dedicated to Prof. Dr. Dr. hc mult. Ernst Mayr on the occasion of his 100th birthdayThis revised version was published online in March 2004, with corrections to the caption of Figure 6. 相似文献
6.
安徽月山地区是长江中下游地区的重要成岩-成矿区段。本文通过岩石学、岩石化学和同位素地球化学等方面的研究,探讨和阐明了月山地区闪长岩类的形成环境、物质来源、源区特征、岩浆形成与演化机理等。 相似文献
7.
爆炸法处理废旧轮胎制造橡胶粉末技术及关键机理研究 总被引:6,自引:0,他引:6
主要介绍了利用爆炸法处理废旧轮胎制造橡胶粉末的技术 ;探讨了橡胶在爆炸作用下破坏的机理 ,爆炸法中橡胶变形速率与它的剪切模量和断裂韧性的关系 ;分析了利用直接爆炸法处理废旧轮胎的 3种实验结果 ,验证了对轮胎进行预处理的必要性 ,探讨了炸药用量的选择原则 相似文献
9.
揭示了农业污染纠纷的内涵,提出了处理农业污染纠纷的4个“支撑点”,即运用农业技术先行界定,运用监测数据科学鉴证;运用因果关系逻辑推定,强化环境管理,疏通综合处理渠道等。 相似文献
10.