全文获取类型
收费全文 | 17256篇 |
免费 | 142篇 |
国内免费 | 113篇 |
专业分类
安全科学 | 408篇 |
废物处理 | 652篇 |
环保管理 | 1904篇 |
综合类 | 5324篇 |
基础理论 | 3570篇 |
环境理论 | 2篇 |
污染及防治 | 4096篇 |
评价与监测 | 878篇 |
社会与环境 | 616篇 |
灾害及防治 | 61篇 |
出版年
2018年 | 200篇 |
2017年 | 188篇 |
2016年 | 286篇 |
2015年 | 216篇 |
2014年 | 317篇 |
2013年 | 1154篇 |
2012年 | 370篇 |
2011年 | 518篇 |
2010年 | 494篇 |
2009年 | 555篇 |
2008年 | 573篇 |
2007年 | 597篇 |
2006年 | 526篇 |
2005年 | 465篇 |
2004年 | 501篇 |
2003年 | 459篇 |
2002年 | 436篇 |
2001年 | 616篇 |
2000年 | 413篇 |
1999年 | 282篇 |
1998年 | 203篇 |
1997年 | 195篇 |
1996年 | 193篇 |
1995年 | 230篇 |
1994年 | 242篇 |
1993年 | 206篇 |
1992年 | 223篇 |
1991年 | 231篇 |
1990年 | 253篇 |
1989年 | 229篇 |
1988年 | 181篇 |
1987年 | 180篇 |
1986年 | 180篇 |
1985年 | 180篇 |
1984年 | 199篇 |
1983年 | 187篇 |
1982年 | 195篇 |
1981年 | 207篇 |
1980年 | 169篇 |
1979年 | 180篇 |
1978年 | 147篇 |
1977年 | 139篇 |
1974年 | 147篇 |
1973年 | 146篇 |
1968年 | 156篇 |
1967年 | 184篇 |
1966年 | 154篇 |
1965年 | 148篇 |
1964年 | 151篇 |
1963年 | 139篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Physical and chemical (nutrients and major ions) indicators of water quality monitored by Environment Canada between 1977 and 1987 in the Niagara River at Niagara-on-the-Lake and in the St. Lawrence River at Wolfe Island are analyzed for seasonal and annual variations. Parametric methods such as moving averages and linear regression and nonparametric methods (Spearman's rank coefficient) are used to test for the existence of trends in these data. The results indicate that specific conductivity, sodium and chloride have decreased significantly over the period of study. During the same period there is no significant trend for either discharge and nutrients. 相似文献
42.
Kalra N Jain MC Joshi HC Chaudhary R Kumar S Pathak H Sharma SK Kumar V Kumar R Harit RC Khan SA Hussain MZ 《Environmental monitoring and assessment》2003,87(1):93-109
Field experiments were carried out during 1996–97at Gulawathi, Muthiani and Salarpur Villages, IARI Farm, NewDelhi and NCPP Campus, Dadri to evaluate changes in soilcharacteristics and growth of wheat (Triticum aestivum L.),mustard (Brassica juncea L.), lentil (Lence esculentaMoench.), rice (Oryza sativa L.) and maize (Zea mays L.) byvarying amounts of flyash addition (up to 50t ha-1) in soils atsowing/transplanting time of crops. Flyash addition in areasadjoining NCPP Thermal Power Plant, Dadri, Ghaziabad, U.P.ranged from 5–12 t ha-1 yr-1 in 1995–96. Shoot and root growthand yield of test crops at different locations after flyashincorporation resulted in beneficial effects of flyashaddition in most cases. The silt dominant texture of flyashimproved loamy sand to sandy loam textures of the surfacesoils at the farmers' fields. The increased growth in yield ofcrops with flyash incorporation was possibly due tomodifications in soil moisture retention and transmissioncharacteristics, bulk density, physico-chemical characterssuch as pH and EC and organic carbon content. The response offlyash addition in the soil on soil health and cropproductivity needs to be evaluated on long-term sustainableaspects. 相似文献
43.
Pelgrom SM Lamers LP Lock RA Balm PH Bonga SE 《Environmental pollution (Barking, Essex : 1987)》1995,90(3):415-423
Sexually mature female tilapia were exposed to sublethal concentrations of waterborne Cu and/or Cd over 6 days, and subsequent body concentrations of these metals were determined in several organs. The results show that the distribution of Cu and Cd was metal and organ specific. This is demonstrated, for example, by the observation that in tilapia, Cu exposure did not result in Cu accumulation in the liver, whereas in the intestinal wall, notably high concentrations of Cu and Cd were measured in metal exposed fish. In addition to single metal exposed fish, we also determined Cu and Cd body distribution in Cu?Cd co-exposed fish. The observed interactions in metal accumulation were most pronounced in the organs of fish exposed to low, environmentally realistic, metal concentrations. 相似文献
44.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
45.
The Science of Nature - 相似文献
46.
47.
The Science of Nature - 相似文献
48.
Defense Mechanisms of Arthropods, no. 96; no. 95: Eisner et al.: Chemoecology (in press) 相似文献
49.
50.
J. Heinze H. Remmert F. L. Boschke D. Reinen L. Jaenicke 《Die Naturwissenschaften》1983,70(11):575-576