全文获取类型
收费全文 | 2683篇 |
免费 | 197篇 |
国内免费 | 469篇 |
专业分类
安全科学 | 367篇 |
废物处理 | 40篇 |
环保管理 | 304篇 |
综合类 | 1466篇 |
基础理论 | 365篇 |
环境理论 | 1篇 |
污染及防治 | 193篇 |
评价与监测 | 157篇 |
社会与环境 | 241篇 |
灾害及防治 | 215篇 |
出版年
2024年 | 7篇 |
2023年 | 38篇 |
2022年 | 60篇 |
2021年 | 84篇 |
2020年 | 73篇 |
2019年 | 68篇 |
2018年 | 87篇 |
2017年 | 94篇 |
2016年 | 110篇 |
2015年 | 101篇 |
2014年 | 121篇 |
2013年 | 192篇 |
2012年 | 162篇 |
2011年 | 205篇 |
2010年 | 153篇 |
2009年 | 164篇 |
2008年 | 96篇 |
2007年 | 181篇 |
2006年 | 185篇 |
2005年 | 161篇 |
2004年 | 108篇 |
2003年 | 154篇 |
2002年 | 111篇 |
2001年 | 105篇 |
2000年 | 81篇 |
1999年 | 71篇 |
1998年 | 68篇 |
1997年 | 52篇 |
1996年 | 38篇 |
1995年 | 48篇 |
1994年 | 35篇 |
1993年 | 27篇 |
1992年 | 34篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 3篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3349条查询结果,搜索用时 656 毫秒
851.
张艳丽 《防灾科技学院学报》2012,14(3):88-94
清代建都北京,在这里实行特殊的行政管理制度,与之相适应,救灾组织系统也与各地不同。清代北京地区政府救灾组织系统的主要特点有三:一是旗、汉分城办理。清初实行的旗、汉分城居住政策,导致北京城市居址环境的变迁。内城八旗救灾事务由八旗都统负责,外五城救灾事务由五城察院负责。这一特点既与清代逐渐演变形成的特殊官制有关,又与中央集... 相似文献
852.
Watersheds are under increasing pressure worldwide, as expanding human activities coupled with global climate change threaten the water security of people downstream. In response, some communities have initiated investments in watershed services (IWS), a general term for policy-finance mechanisms that mitigate diverse watershed threats and promote ecosystem-based adaptation. Here, we explore the potential for increasing the uptake and impact of IWS, evaluating what limits its application and how institutional, financial, and informational barriers can be overcome. Our analysis complements the growing literature on individual programs by identifying levers at regional and global scales. We conclude that mainstreaming IWS as a cost-effective strategy alongside engineered approaches will require advances that (i) lower institutional barriers to implementation and participation in IWS; (ii) introduce structural market changes and standards of practice that account for the value of watersheds’ natural capital; (iii) develop practical tools and metrics of IWS costs and benefits; and (iv) share success stories of replicable institutional and financial models applied in varied contexts. 相似文献
853.
854.
从水资源短缺、水环境污染、城市环境污染等多方面分析了滇中城市群的环境脆弱性,在此基础上,提出了滇中城市群可持续发展的对策。 相似文献
855.
856.
C. Goumy A. M. Beaufrère C. Francannet A. Tchirkov H. Laurichesse Delmas F. Geissler D. Lemery P. J. Dechelotte P. Vago 《黑龙江环境通报》2005,25(8):653-655
We described a new case of mosaic isochromosome 20q revealed by amniocentesis. The propositus presented with craniofacial dysmorphism, clubfeet, and vertebral abnormalities. A 46,XX,i(20)(q10)[14]/46,XX[1] karyotype was confirmed by FISH on cultured cells. The pregnancy was terminated. From review of literature, fetus with mosaic isochromosome 20q identified on amniocentesis are most likely to be phenotypically and cytogenetically normal after birth. So we performed CGH and array-CGH to exclude another possible imbalance. We discuss here the possible relation between this chromosomal abnormality and the abnormal phenotype. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
857.
Fuelwood is one of the major sources of energy in the domestic sector across the rural areas,especially in the developing regions across the world.The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area.The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region,thus indicating the livelihood conditions.Since land-use land-cover change is the key driver to the change in resource availability of a region,the present study has tried to analyze the landcover changes over a period 28 years.The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics,which directly affect the resource production.Based on the existing consumption pattern,the total consumption of fuelwood in the watershed ranges fiom a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year.Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system. 相似文献
858.
859.
Measurements of flammability and explosion parameters for dust/air mixtures require uniform dispersion of the dust cloud inside the test vessel. In a previous work, we showed that, in the standard 20 L sphere, the dust injection system does not allow generation of a uniform cloud, but rather high gradients of dust concentration are established. In this work, we used a previously validated three-dimensional CFD model to simulate the dust dispersion inside the 20 L sphere at different dust nominal concentrations (and fixed dust diameter). Results of numerical simulations have shown that, as the dust nominal concentration is increased, sedimentation prevails and, thus, when ignition is provided, the dust is mainly concentrated at the vessel walls. 相似文献
860.
长江中下游城市群地区工业重化特征明显,工业水污染排放贡献超过10%,大气污染物占比更超过70%。本文采用迪氏对数指标分解法(LMDI)识别长江中下游城市群污染排放的主要影响因子,对长江中下游城市群重点行业COD、氨氮、SO_2、NO_x排放强度进行分析。将排放强度拆分为末端削减、技术工业和产品结构三个指标,分析2012—2020年和2020—2030年两个时间段内,对污染排放强度降低贡献度最高的影响因素。结果表明,末端削减和技术工艺对污染排放强度降低影响大,贡献值之和约为90%,两者分别代表末端处理技术对污染排放的削减程度,以及高附加值行业单位产值污染物产生水平;COD、SO_2和氨氮的排放强度由末端削减和技术工艺共同作用,NO_x的排放强度较高且未来末端削减水平进步小,未来需要重视该污染物的减排和治理。 相似文献