全文获取类型
收费全文 | 16398篇 |
免费 | 194篇 |
国内免费 | 138篇 |
专业分类
安全科学 | 412篇 |
废物处理 | 710篇 |
环保管理 | 2026篇 |
综合类 | 2599篇 |
基础理论 | 4518篇 |
环境理论 | 5篇 |
污染及防治 | 4262篇 |
评价与监测 | 1108篇 |
社会与环境 | 993篇 |
灾害及防治 | 97篇 |
出版年
2022年 | 135篇 |
2021年 | 112篇 |
2020年 | 114篇 |
2019年 | 110篇 |
2018年 | 213篇 |
2017年 | 256篇 |
2016年 | 349篇 |
2015年 | 288篇 |
2014年 | 481篇 |
2013年 | 1284篇 |
2012年 | 527篇 |
2011年 | 736篇 |
2010年 | 645篇 |
2009年 | 616篇 |
2008年 | 721篇 |
2007年 | 758篇 |
2006年 | 638篇 |
2005年 | 548篇 |
2004年 | 550篇 |
2003年 | 540篇 |
2002年 | 523篇 |
2001年 | 664篇 |
2000年 | 500篇 |
1999年 | 270篇 |
1998年 | 189篇 |
1997年 | 219篇 |
1996年 | 224篇 |
1995年 | 253篇 |
1994年 | 248篇 |
1993年 | 190篇 |
1992年 | 205篇 |
1991年 | 186篇 |
1990年 | 207篇 |
1989年 | 199篇 |
1988年 | 156篇 |
1987年 | 174篇 |
1986年 | 157篇 |
1985年 | 161篇 |
1984年 | 154篇 |
1983年 | 146篇 |
1982年 | 134篇 |
1981年 | 125篇 |
1980年 | 116篇 |
1979年 | 130篇 |
1978年 | 104篇 |
1977年 | 116篇 |
1975年 | 88篇 |
1974年 | 87篇 |
1973年 | 97篇 |
1972年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
12.
13.
JOSEPH P. DUDLEY 《Conservation biology》1995,9(5):1332-1334
14.
Fourteen unpolluted Finnish headwater lakes with pH values varying from 4.8 to 7.0 were studied for trace-metal concentrations in water, sediment, aquatic plants (Nuphar luteum L., Sparganium sp.), aquatic insect larvae (Limnophilus sp., Phryganea sp.) and fish (Esox lucius L., Perca fluviatilis L., Coregonus sp., Salvelinus fontinalis L., Salmo trutta L.). Trace-metal deposition was estimated by analysing the snowpack. Non-parametric correlation analysis was carried out between trace metal concentrations in biota and pH, ANC, TOC, CA + Mg concentration in water and a given metal concentration in water and sediment. Bioaccumulation of several trace metals increased with increasing acidity and decreasing ANC in water. This was especially true for Pb and Cd. Aquatic plants were, in general, the best indicator group concerning differences in trace-metal bioaccumulation in lakes with different acidity. There was some evidence that a higher concentration of TOC in water may reduce bioaccumulation of Pb, Cd and Zn in aquatic plants and fish. The copper concentration in sediment was the only background variable explaining Cu concentration in aquatic insects. Multivariate analysis of the whole background data gave comparable preliminary results. Over 80% of the trace metal concentrations in biota of different lakes was explained by the background variables. In general, elevated concentrations of most of these trace metals can be expected to occur in the biota of acidified low calcareous lakes. 相似文献
15.
Rate-temperature responses in scyphozoan medusae and polyps 总被引:1,自引:0,他引:1
The effects of temperature on oxygen consumption and spontaneous rhythmic activity have been investigated in various stages of the life histories of 3 species of jellyfish from the Chesapeake Bay, USA. All 3 species clearly show the ability to acclimate positively to temperature change. Thermal sensitivity of metabolism in the winter medusa Cyanea capillata fulva is fairly low at temperature intervals which are experienced in nature. Polyps of the two summer medusae, Chrysaora quinquecirrha and Aurelia aurita, show reduced metabolic sensitivity at temperatures normally accompanying high developmental activity and the onset of strobilation. 相似文献
16.
Temperature and metabolic rate in sedentary fish from the Antarctic,North Sea and Indo-West Pacific Ocean 总被引:2,自引:0,他引:2
Resting metabolic rate
was measured in demersal stages of the teleostNotothenia neglecta Nybelin from the South Orkney Islands, Antarctica, from 1985 to 1987. The relationship between
and body mass (Mb) conformed to the general relationship
, wherea is a proportionality constant andb is the scaling exponent.
(mg O2 h–1) was found to scale toMb
(0.82±0.011) in the summer (November to April, 1.6 to 1 850 g,n=56) and toMb
(0.76±0.013) in the winter (May to October, 0.9 to 1 850 g,n=57) (values ofb are means ± SD). Although the scaling exponents were significantly different (P<0.01),
was similar in the juvenile stages of summer- and winter-caught fish matched for body mass. The effects of activity on oxygen consumption was studied using a Brett respirometer. Adult stages had a factorial aerobic scope for activity
of 5.7, which is similar to that reported for demersal fish from temperate latitudes. The effects of temperature on resting metabolism was investigated in fish with similar sedentary lifestyles from the North Sea (Agonus cataphractus andMyoxocephalus scorpius) and the Indo-West Pacific (Paracirrhites forsteri, P. arcatus, Neocirrhites armatus andExallias brevis). Extrapolated values of
for the tropical species approached zero at 5 to 10°C. For a standard 50 g fish,
for the tropical species at 25°C was in the range 3.4 to 4.4 mg O2 h–1, compared with 1.3 mg O2 h–1 forNotothenia neglecta at its acclimation temperature. Thus, the maximum metabolic rate of sedentary tropical species at 24°C is likely to be 2 to 4 times higher than inN. neglecta at 0°C. This suggests that the energy available for sustained activity
is significantly lower in cold- than in warm-water fish. 相似文献
17.
Summary As stated at the beginning of this paper conclusions reached thus far cannot be discussed in this paper. However, a great deal of information is available for examination.EPA displayed its ability to coordinate widely separated laboratories, both Federal and private, into a smooth working team in a very short period of time. A very comprehensive study plan was also developed and implemented quickly. EPA was fortunate to have already had GCA under contract when the emergency arose. In no small part the success of the field effort was due to the managerial and technical abilities of the GCA team.Within a period of 6 weeks a plan was developed, a prime contractor retained, subcontractors hired, and field activities begun. Within a period of 3 months in excess of 8600 field samples were collected and over 12,000 field and QC samples were analyzed. During this same period 2 major data systems were developed, debugged, and placed into operation.In short this EPA project was probably the most comprehensive multimedia field project ever attempted by EPA and certainly the data is being subjected to the most strenuous quality control measures ever imposed by this Agency. The entire program is presently under peer review and the results are being prepared for publication by EPA Headquarters.Note. Originally intended to be published as part of the special issue on Exposure Monitoring: An International Workshop (Las Vegas, Nevada, October 19–22, 1981). 相似文献
18.
Onianwa PC 《Environmental monitoring and assessment》2001,71(1):13-50
This article reviews the literatureon the use of mosses for monitoring atmospheric metalpollution. It discusses the nature of mosses, themechanisms for moss uptake of metals from the air andwet precipitation, the various forms in which mossesare used for this purpose, and cases in which mosseshave been used for monitoring local hot spots ofpollution, and regional patterns of metal pollution.Also highlighted are the questions of uptake of metalsfrom the substrates, interspecies differences, and acomparison of the effectiveness of mosses with otherindicator materials, among other issues. 相似文献
19.
Quevauviller P 《Journal of environmental monitoring : JEM》1999,1(3):48N-49N
Following the decision of the European Parliament and of the Council of 22 December 1998, The European Commission has launched its Fifth Framework Programme for Research, Technological Development and Demonstration (RTD) which will run from 1999 to 2002. The activities will be carried out in the frame of four thematic programmes and three horizontal ones. The first calls for proposals were published in March 1999. Detailed information on the work programme of each activity is available through the Internet at the following address http://www.cordis.lu/fp5 and through direct contact with the programme's help-desks. The present summary gives an outline of environment-related research activities covered by 5th FWP. 相似文献
20.
Quevauviller P 《Journal of environmental monitoring : JEM》2000,2(4):292-299
The concepts of accuracy and traceability as applied to environmental analysis are still prone to misunderstandings. While accuracy refers to the closeness of analytical values to "true values" (trueness) and among various repetitions (precision), the term traceability implies a link of data obtained to established references through an unbroken chain of comparisons all with stated uncertainties. These misunderstandings, possibly occurring among the analytical community, may have consequences on environmental data interpretation. Recent discussions in the field of environmental speciation analysis illustrated that accuracy and traceability issues are still not firmly established within the environmental chemistry community. This paper discusses this issue, taking methylmercury as a case study. 相似文献