全文获取类型
收费全文 | 11113篇 |
免费 | 35篇 |
国内免费 | 259篇 |
专业分类
安全科学 | 56篇 |
废物处理 | 841篇 |
环保管理 | 1327篇 |
综合类 | 1545篇 |
基础理论 | 3363篇 |
环境理论 | 2篇 |
污染及防治 | 2207篇 |
评价与监测 | 1083篇 |
社会与环境 | 948篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 12篇 |
2022年 | 49篇 |
2021年 | 31篇 |
2020年 | 33篇 |
2019年 | 27篇 |
2018年 | 1501篇 |
2017年 | 1407篇 |
2016年 | 1245篇 |
2015年 | 193篇 |
2014年 | 117篇 |
2013年 | 122篇 |
2012年 | 551篇 |
2011年 | 1438篇 |
2010年 | 764篇 |
2009年 | 658篇 |
2008年 | 977篇 |
2007年 | 1305篇 |
2006年 | 86篇 |
2005年 | 86篇 |
2004年 | 89篇 |
2003年 | 122篇 |
2002年 | 152篇 |
2001年 | 70篇 |
2000年 | 54篇 |
1999年 | 45篇 |
1998年 | 47篇 |
1997年 | 29篇 |
1996年 | 28篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 4篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1961年 | 1篇 |
1952年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Bosch J 《Die Naturwissenschaften》2002,89(12):575-578
Female midwife toads (genus Alytes) emit highly variable reciprocal calls of unclear function prior to and during courtship. In some species, female-female competition, expressed as physical fighting, has been reported. Males of Majorcan midwife toads (Alytes muletensis) show phonotactic response to female calls, and females of Iberian midwife toads (Alytes cisternasii) respond differently according to the male call characteristics. In this study, I test the hypothesis of female-female acoustic competition as an additional function of female reciprocal calls. Playback tests indicate that female calls are not clearly involved in female acoustic competition in the Iberian midwife toad, therefore female calls could be directed at males rather than towards competitive females. 相似文献
52.
电厂锅炉清洗废水治理工艺 总被引:3,自引:0,他引:3
电厂锅炉清洗废水中,含有高浓度的柠檬酸和丙酮肟等有机污染物。经试验,采取原水作适当稀释后,进行好氧曝气-活性炭生物膜法二级处理,CODcr总去除率可达88%-90%;BOD5去除率为90%。经两经处理后的出水,CODcr<100mg/l,BOD5<50mg/l,可达到较好的处理效果。 相似文献
53.
西昆仑山区土壤垂直带谱 总被引:1,自引:0,他引:1
西昆仑山区位于青藏高原西北隅,高山深谷,原面广阔,地形复杂,气候多样,致使本区土壤垂直带谱类型众多,概分为极干旱、干旱、半干旱和高寒干旱、高寒半干旱5个类型。其中干旱和半干旱型土壤垂直带谱中广布着草原和草甸草原,是塔里木盆地南缘重要的天然牧场。特别是半干旱型中还有云杉林分布,是昆仑山系唯一森林分布区。 本区土壤垂直带谱在边缘山脉与内部山脉之间,低海拔山地与耸立在5000m左右高原面上的高海拔山地之间有明显的差别。 相似文献
54.
55.
56.
57.
Gamergates (i.e. mated reproductive workers) are mostly known from ant species within the Ponerinae. We report here the discovery of gamergates in two species of the subfamily Myrmicinae. Until now, mated reproductive females in colonies of myrmicine species have been considered morphologically distinct from the worker caste. However, in two species of the myrmicine Metapone (Metapone madagascarica and a newly discovered, not yet described Metapone species) all workers have six ovarioles and a spermatheca; and some of them are mated. There are no morphological differences between mated and non-mated workers. Field observations and laboratory studies indicate that colonies of the Metapone species can reproduce with gamergates only. 相似文献
58.
Although amphibians are highly vocal, they generally emit only a limited number of acoustic communication signals. We report here the extraordinarily rich vocal repertoire of Amolops tormotus, a ranid species in China. These frogs produce countless vocalizations, some of which share features of birdsong or primate calls, e.g., ultrasonic frequency components, multiple upward and downward FM sweeps, and sudden onset and offset of selective harmonic components within a call note. Frame-by-frame video analysis of the frog's calling behavior suggests the presence of two pairs of vocal sacs that may contribute to the remarkable call-note complexity in this species. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-002-0335-x. 相似文献
59.
Aysen Müezzinoğlu Tolga Elbir Abdurrahman Bayram 《Environmental Engineering and Policy》1998,1(2):109-116
In this study, an inventory of air pollutant emission estimates from major air polluting sources in Turkey for period between 1985 and 2005 with 5-year intervals were estimated. Inventory covers anthropogenic sources of five major air pollutants of particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides and non-methane volatile organic compounds. Their break-down with respect to main activity sectors were shown and their distribution by the largest industrial source categories were worked out as annual estimates. This inventory and its analysis point to serious environmental implications of air pollutants and a need to develop a policy plan for reducing these emissions. 相似文献
60.
膜生物反应器技术的研究和应用展望 总被引:25,自引:1,他引:25
膜生物反应器是将膜分离技术与生物上结合而开发的新型系统,该文就膜生物反应器的特征、研究现状、不同形式反应器的技术参数与处理效果等。进行了综述、由于膜生物反应器具有明显的优点,故愈来愈受到人们的重视、成为研究的热点之一。膜生物反应器的研究和范围不断拓宽,有的已进入污水处理实用阶段,建议今后在开发适合于分离的特种膜方面,在组件形式,操作条件,清洗方式等对膜通量的影响方面,以及生物作用与膜分离工艺的相互 相似文献