全文获取类型
收费全文 | 27248篇 |
免费 | 237篇 |
国内免费 | 190篇 |
专业分类
安全科学 | 704篇 |
废物处理 | 1024篇 |
环保管理 | 3364篇 |
综合类 | 6941篇 |
基础理论 | 6280篇 |
环境理论 | 9篇 |
污染及防治 | 6550篇 |
评价与监测 | 1501篇 |
社会与环境 | 1160篇 |
灾害及防治 | 142篇 |
出版年
2022年 | 210篇 |
2018年 | 344篇 |
2017年 | 313篇 |
2016年 | 485篇 |
2015年 | 381篇 |
2014年 | 546篇 |
2013年 | 1912篇 |
2012年 | 688篇 |
2011年 | 961篇 |
2010年 | 838篇 |
2009年 | 959篇 |
2008年 | 1013篇 |
2007年 | 1030篇 |
2006年 | 901篇 |
2005年 | 817篇 |
2004年 | 790篇 |
2003年 | 774篇 |
2002年 | 743篇 |
2001年 | 1000篇 |
2000年 | 702篇 |
1999年 | 463篇 |
1998年 | 312篇 |
1997年 | 325篇 |
1996年 | 330篇 |
1995年 | 390篇 |
1994年 | 398篇 |
1993年 | 342篇 |
1992年 | 333篇 |
1991年 | 371篇 |
1990年 | 391篇 |
1989年 | 362篇 |
1988年 | 280篇 |
1987年 | 271篇 |
1986年 | 273篇 |
1985年 | 258篇 |
1984年 | 281篇 |
1983年 | 281篇 |
1982年 | 288篇 |
1981年 | 293篇 |
1980年 | 242篇 |
1979年 | 277篇 |
1978年 | 204篇 |
1977年 | 202篇 |
1976年 | 186篇 |
1975年 | 185篇 |
1974年 | 201篇 |
1973年 | 202篇 |
1972年 | 189篇 |
1967年 | 235篇 |
1966年 | 190篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
The past two decades have witnessed an increase in the exploration for, and development of, mineral resources at Arctic latitudes. Such effort has resulted in the commencement of production at a number of different localities in close proximity to the ocean. Since proximity to a source of transportation for the conveyance of concentrates to the market is a primary requirement governing the economic decisions for the mine to proceed, it is logical that ore deposits near a coastline are primary targets for development.
Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media. 相似文献
Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media. 相似文献
13.
14.
15.
16.
17.
Ontogenetic change of habitat depths of Nautilus pompilius in the Philippines (Tañon Strait) and Fiji is considered by comparing 18O/16O ratios in septa and cameral fluid of live-caught specimens and ambient sea-water. 18O values of cameral liquid become heavier with decreasing volume within a chamber, which may be due to isotopic fractionation during discharge across the siphuncular wall. All of the seven Philippine and Fiji specimens analyzed show a distinct change in 18O from light values in the first seven septa to heavier values in the succeeding septa. Two different isotopic temperature scales are obtained for the Fiji and Philippine populations, suggesting a differential vital effect of metabolism between them. Sightly light 18O values in Septa 1 to 7 and hatching at relatively high temperatures in aquaria both suggest that N. pompilius hatch at the shallowest depths within their inhabitable vertical range. Depths of postembryonic animals in the Philippines and Fiji waters estimated from the isotopic temperature-depth diagrams range from 120 to 160 m and from 440 to 520 m, respectively, both of which correlate well with capture records. More than several tens of small-scale 18O cycles are detected in the sequence of nacreous layers within the single septum of a submature Philippine specimen. This can be interpreted as reflecting daily vertical migration. 相似文献
18.
Igliski B. Skrzatek M. Kujawski W. Cichosz M. Buczkowski R. 《Environment, Development and Sustainability》2022,24(1):77-111
Environment, Development and Sustainability - Renewable energy (RE) plays an increasingly important role in the economy of almost every country in the world. In order to examine the state of... 相似文献
19.
20.