全文获取类型
收费全文 | 15942篇 |
免费 | 180篇 |
国内免费 | 263篇 |
专业分类
安全科学 | 457篇 |
废物处理 | 686篇 |
环保管理 | 1953篇 |
综合类 | 2818篇 |
基础理论 | 4028篇 |
环境理论 | 10篇 |
污染及防治 | 4297篇 |
评价与监测 | 1101篇 |
社会与环境 | 919篇 |
灾害及防治 | 116篇 |
出版年
2023年 | 114篇 |
2022年 | 251篇 |
2021年 | 206篇 |
2020年 | 168篇 |
2019年 | 186篇 |
2018年 | 301篇 |
2017年 | 281篇 |
2016年 | 439篇 |
2015年 | 335篇 |
2014年 | 482篇 |
2013年 | 1252篇 |
2012年 | 597篇 |
2011年 | 813篇 |
2010年 | 604篇 |
2009年 | 666篇 |
2008年 | 749篇 |
2007年 | 755篇 |
2006年 | 629篇 |
2005年 | 583篇 |
2004年 | 464篇 |
2003年 | 466篇 |
2002年 | 454篇 |
2001年 | 561篇 |
2000年 | 402篇 |
1999年 | 246篇 |
1998年 | 155篇 |
1997年 | 175篇 |
1996年 | 175篇 |
1995年 | 218篇 |
1994年 | 216篇 |
1993年 | 177篇 |
1992年 | 150篇 |
1991年 | 185篇 |
1990年 | 181篇 |
1989年 | 169篇 |
1988年 | 127篇 |
1987年 | 116篇 |
1986年 | 120篇 |
1985年 | 95篇 |
1984年 | 110篇 |
1983年 | 115篇 |
1982年 | 121篇 |
1981年 | 111篇 |
1980年 | 98篇 |
1979年 | 115篇 |
1978年 | 76篇 |
1977年 | 76篇 |
1975年 | 79篇 |
1973年 | 75篇 |
1967年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Paul B. Thompson 《Journal of Agricultural and Environmental Ethics》2010,23(3):209-227
Recent publications by Pogge (Global ethics: seminal essays. St. Paul: Paragon House 2008) and by Singer (The life you can save: acting now to end world poverty. New York: Random House 2009) have resuscitated a debate over the justifiability of famine relief between Singer and ecologist Garrett Hardin in the 1970s.
Yet that debate concluded with a general recognition that (a) general considerations of development ethics presented more
compelling ethical problems than famine relief; and (b) some form of development would be essential to avoiding the problems
of growth noted by Hardin. Better than renewing the debate, we should recognize two points. First, food needs do indeed evoke
a moral response that is more direct and compelling than the philosophical positions often generated to rationalize a duty
to bring aid. As such the argument for feeding hungry people cannot be generalized into a paradigm for development ethics
without distortions that undercut the morally valid elements in Singer’s original argument. Second, contrary to prevailing
assumptions in present day development ethics, food aid and famine relief continue to be important priorities for international
agencies, notably the World Food Program. Emergency food assistance, the nominal topic of Singer’s original article, thus
is an important issue for agricultural as well as development ethics, though one that should indeed be seen as distinct from
more complex duties to address the conditions of chronic poverty and underdevelopment. 相似文献
142.
Accumulation and biological cycling of heavy metal in four salt marsh species, from Tagus estuary (Portugal) 总被引:2,自引:0,他引:2
Pools of Zn, Cu, Cd and Co in leaf, stem and root tissues of Sarcocornia fruticosa, Sarcocornia perennis, Halimione portulacoides and Spartina maritima were analyzed on a bimonthly basis, in a Tagus estuary salt marsh. All the major concentrations were found in the root tissues, being the concentrations in the aboveground organs neglectable for sediment budget proposes, as seen by the low root-aboveground translocation. Metal annual accumulation, root turnovers and cycling coefficients were also assessed. S. maritima showed the higher root turnovers and cycling coefficients for most of the analyzed metals, making this a phytostabilizer specie. By contrast the low root turnover, cycling coefficient and low root necromass generation makes S. perennis the most suitable specie for phytoremediation processes. Although the high amounts of metal return to the sediments, due to root senescence, salt marshes can still be considered sinks of heavy metals, cycling heavy metals mostly between sediment and root. 相似文献
143.
T.M. McIntire O.S. Ryder P.L. Gassman Z. Zhu S. Ghosal B.J. Finlayson-Pitts 《Atmospheric environment (Oxford, England : 1994)》2010,44(7):939-944
It is commonly assumed that atmospheric oxidation of hydrocarbon particles or hydrocarbon coatings on particles leads to polar products and increased water uptake, altering atmospheric visibility and increasing the likelihood they will act as cloud condensation nuclei (CCN). We show here through laboratory experiments that increased water uptake depends on the 3-dimensional structure of the particles. Laboratory studies of particles formed during ozonolysis of surface-bound alkenes, present as terminally unsaturated self-assembled monolayers (C8= SAM) on a silica substrate, were carried out at room temperature and 1 atm pressure. SAMs were exposed to ~1013 O3 molecules cm?3 for 40 min and resultant particles were analyzed using single particle Fourier transform infrared micro-spectroscopy (micro-FTIR) and secondary ion mass spectroscopy (SIMS). Spectroscopy results show that –COOH and other polar groups are formed but are buried inside a hydrophobic shell, consistent with earlier observations (McIntire et al., 2005, Moussa et al., 2009) that water uptake does not increase after reaction of the terminal alkene with O3. These insights into the 3-D structure of particles formed on oxidation have important implications for the ability of secondary organic aerosols to act as CCN. In addition, the nature of the surface of the particles is expected to determine their uptake into biological systems such as the surface of the lungs. 相似文献
144.
B. Miljevic K.E. Fairfull-Smith S.E. Bottle Z.D. Ristovski 《Atmospheric environment (Oxford, England : 1994)》2010,44(18):2224-2230
Reactive oxygen species (ROS) and related free radicals are considered to be key factors underpinning the various adverse health effects associated with exposure to ambient particulate matter. Therefore, measurement of ROS is a crucial factor for assessing the potential toxicity of particles. In this work, a novel profluorescent nitroxide, BPEAnit, was investigated as a probe for detecting particle-derived ROS. BPEAnit has a very low fluorescence emission due to inherent quenching by the nitroxide group, but upon radical trapping or redox activity, a strong fluorescence is observed. BPEAnit was tested for detection of ROS present in mainstream and sidestream cigarette smoke. In the case of mainstream cigarette smoke, there was a linear increase in fluorescence intensity with an increasing number of cigarette puffs, equivalent to an average of 101 nmol ROS per cigarette based on the number of moles of the probe reacted. Sidestream cigarette smoke sampled from an environmental chamber exposed BPEAnit to much lower concentrations of particles, but still resulted in a clearly detectible increase in fluorescence intensity with sampling time. It was calculated that the amount of ROS was equivalent to 50 ± 2 nmol per mg of particulate matter; however, this value decreased with ageing of the particles in the chamber. Overall, BPEAnit was shown to provide a sensitive response related to the oxidative capacity of the particulate matter. These findings present a good basis for employing the new BPEAnit probe for the investigation of particle-related ROS generated from cigarette smoke as well as from other combustion sources. 相似文献
145.
146.
F.L. Voelz S.I. Weinberg B.G. Gower 《Journal of the Air & Waste Management Association (1995)》2013,63(12):935-942
Gross average automotive exhaust emissions data collected by the Atlantic Richfield Clean Air Caravan during the summer of 1970 showed only slight geographical variations when the specific makes were ignored. When considering specific makes, significant differences were found on an average emissions basis. Vehicle population—emission distributions showed wide variations in the 50% population levels and in the percent of vehicles with emissions greater than specified values. Hydrocarbon (HC) and carbon monoxide (CO) data are given on a gross basis for the 1970, 1968-69, 1966-67, and pre-1966 model year group vehicles. Average HC and CO emissions and vehicle population-Idle emissions distribution curves are included for specific make vehicles in selected areas. 相似文献
147.
Susanna B. Levitt David P. Chock 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1091-1092
Pollutant data from the Los Angeles Basin were analyzed for weekday-weekend differences for the smog months of June through September 1972 and 1973. The pollutants investigated were oxidant, NO, NO2, total hydrocarbons (HC), CO, and particulates. In order to maintain the diurnal variation, the concentration percentiles were calculated for each weekday and weekend hour. 相似文献
148.
Terry A. Ferrar Alan B. Brownstein 《Journal of the Air & Waste Management Association (1995)》2013,63(6):602-604
Confronted with shortages of low sulfur content residual fuel oil and, consequently, faced with the threat of social and economic upheaval, several air pollution control authorities in the Northeastern states were forced to relax hard-won air quality standards during the winter of 1972. The authorities did so by granting variances to their sulfur content standards for residual fuel oil. This paper examines the institutional characteristics of these variance policies from an economic incentive standpoint. After setting up desirable structural criteria for institutional design of such crisis policies, the authors examine the experience of the winter of 1972 and arrive at policy guidelines which recommend themselves for consideration in future periods of fuel oil shortages. 相似文献
149.
Warren B. Johnson 《Journal of the Air & Waste Management Association (1995)》2013,63(6):563-574
Regional scale air quality simulation models covering spatial scales of thousands of kilometers are finding increasing applications in studies of acid deposition and other air pollution problems. The purpose of this paper is to familiarize the nonexpert with the characteristics of the major types of interregional air quality models currently in use: Eulerian grid, statistical trajectory, and Lagrangian trajectory. The basic features, advantages, and disadvantages of each of these modeling approaches are summarized, as are the important limitations and problems associated with interregional modeling in general. Typical applications are illustrated using examples from the use of a representative Lagrangian trajectory model, ENAMAP, over the eastern North American area. 相似文献
150.
Ralph M. Rotty David B. Reister 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1111-1115
A reference scenario for CO2 emissions was developed using a model of world energy supply and demand. In the reference scenario, world GNP and world energy demand increase at average rates of 2.1 percent per year and 1.5 percent per year, respectively during the period 1975-2100. The corresponding annual CO2 emissions rise to a maximum of 16 gigatons of carbon around 2050 and then decline as a result of a transition to nonfossil fuel energy systems. A modified scenario for high CO2 emissions was obtained by assuming an abundant supply of low cost coal, thus eliminating the transition. A low case was developed in which the low cost of alternative energy (i.e., solar, nuclear) induces an earlier shift away from fossil fuels. Annual emissions of the three scenarios were used as input to a global carbon cycle model and the CO2 buildup in the atmosphere during the period 1980-2100 was determined by the model. All three scenarios showed continuous rises in atmospheric CO2 concentration. The reference scenario reached 775 ppm by 2100. The high CO2 case resulted in concentrations of over 1040 ppm, and for the low case the 2100 concentration was just under 700 ppm. If the climate theory is correct, even 700 ppm is sufficient to give significant climate warming, but by experiencing the change gradually over a century, adaptation may not be painful. An early transition to nonfossil fuel supplies makes the problem less severe but does not eliminate it. 相似文献