全文获取类型
收费全文 | 1426篇 |
免费 | 6篇 |
国内免费 | 43篇 |
专业分类
安全科学 | 45篇 |
废物处理 | 86篇 |
环保管理 | 142篇 |
综合类 | 241篇 |
基础理论 | 340篇 |
环境理论 | 1篇 |
污染及防治 | 395篇 |
评价与监测 | 101篇 |
社会与环境 | 118篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 13篇 |
2022年 | 44篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 54篇 |
2017年 | 23篇 |
2016年 | 28篇 |
2015年 | 49篇 |
2014年 | 35篇 |
2013年 | 119篇 |
2012年 | 36篇 |
2011年 | 63篇 |
2010年 | 63篇 |
2009年 | 73篇 |
2008年 | 71篇 |
2007年 | 60篇 |
2006年 | 44篇 |
2005年 | 43篇 |
2004年 | 77篇 |
2003年 | 65篇 |
2002年 | 43篇 |
2001年 | 102篇 |
2000年 | 43篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 20篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1980年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1971年 | 5篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1959年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有1475条查询结果,搜索用时 203 毫秒
991.
L. Erdős Cs. Tölgyesi Z. Bátori Yu. A. Semenishchenkov M. Magnes 《Russian Journal of Ecology》2017,48(4):350-357
Eastern Austrian forest-steppe remnants are extremey important both from conservation and a scientific perspective, yet case studies integrating the examination of the grassland and the forest components are relatively scarce. Consequently, the knowledge on how the pattern of forested vs. non-forested patches influences species composition and diversity remains rather limited. In this study, we compared three sites with different forest/grassland proportions: grassland with a low canopy cover, a mosaic area with alternating forest and grassland habitats, and a forest with some canopy gaps. Our aim was to find out which one of them is the best for conservation purposes. We found that the grassland and the mosaic area had a similar composition, while the forested one was distinct from them. The mosaic vegetation seemed to be the most species rich, also hosting a high number of red-listed species. Beside forest-related and grassland-related species, the mosaic plot also supported some edge-related plants. We conclude that the preservation of mosaic-like forest- grassland habitats is the most favorable for conservation aims. Nevertheless, several species, among them some red-listed ones, were clearly linked either to the forest or to the grassland plot. Therefore, even though mosaics deserve a special attention, open grasslands and xeric forests should also be preserved. 相似文献
992.
B. C. Gómez-Meda G. M. Zúñiga-González L. V. Sánchez-Orozco A. L. Zamora-Perez J. P. Rojas-Ramírez A. D. Rocha-Muñoz A. A. Sobrevilla-Navarro M. A. Arellano-Avelar A. A. Guerrero-de León J. S. Armendáriz-Borunda M. G. Sánchez-Parada 《Environmental monitoring and assessment》2017,189(10):522
The Santiago River is one of the most contaminated rivers in Mexico, with heavy metal levels above the allowed limits. Scientific evidence indicates that chronic heavy metal exposure leads to cytogenotoxic effects. The aims of this study were to evaluate the genotoxic and cytotoxic effects of such exposure in buccal mucosa cells by micronucleus (MN) assay and to identify other nuclear abnormalities (NAs), such as nuclear buds (NBUDs), binucleated cells (BNs), pyknotic nuclei (PNs), karyorrhexis (KX), karyolysis (KL), and abnormally condensed chromatin (CC). Assays were performed on samples from four populations located alongside the Santiago River that are under chronic exposure to heavy metals and other metals (HMMs), and the results were compared with those of a population without exposure to HMMs. The exposed group showed increased frequencies of NAs (KX, CC, and KL), which are associated with cytotoxic damage, and NBUDs, which are associated with genotoxic damage. Increased frequencies of NBUDs and CC were observed in subjects from El Salto/Juanacatlán, Ocotlán, and Paso de Guadalupe, and an increase in KX frequency was observed in subjects from El Salto/Juanacatlán. Significant differences in KL frequency were observed in subjects from La Barca, El Salto/Juanacatlán, Paso de Guadalupe, and Ocotlán. Predictors for increased development of MNs and NBUDs were high concentrations of Al, Zn, and Cu. In conclusion, chronic exposure to HMMs, especially Al, Cu, and Zn, in the studied population could be related to increased frequencies of NAs, such as NBUDs, KX, CC, and KL, in the buccal mucosa cells. 相似文献
993.
J. Sun X. Z. Li X. W. Wang J. J. Lv Z. M. Li Y. M. Hu 《Russian Journal of Ecology》2011,42(2):123-132
Permafrost wetlands are one of the most sensitive plant communities in response to global warming. Global warming could induce natural plant communities to shift into cooler climate zones, or extirpate. To understand how plant communities in permafrost wetlands are affected by global warming, we examined the patterns of plant species diversity in the 24 permafrost wetlands in the Great Hing’an Mountains along a latitudinal gradient. This gradient was characterized by a northward decline in mean annual temperature (Δ = 3.5°C) and mean annual precipitation (Δ = 38.7 mm). Our results indicated that latitudinal patterns in species diversity existed in the permafrost wetlands. The numbers of family, genus and species, the Gleason index and Shannon-Wiener index for shrubs decreased linearly with decreasing latitude, but increased for herbaceous plants. The latitudinal patterns in species diversity had influenced strongly by temperature. Simple linear regression yielded about 2 decreases in shrub number and 9 increases in herbaceous species number with an increase of mean annual temperature by 1°C, with 0.33 decreases in shrub diversity and 0.29 increases in herbaceous species diversity. If temperature warms 3.7°C by 2100, herbaceous plants might increase in the permafrost wetlands, with species number increasing 48% or 6 times and species diversity increasing 40% or 2 times; and some shrub species might decrease and even disappear in part of the areas with lower latitude, with species number decreasing 50–100% and species diversity decreasing 69–100%. The permafrost wetlands in the Great Hing’an Mountains might continue degenerating and shift northward with global warming over the next century. 相似文献
994.
Mohammad K. Younes Z.M. Nopiah N.E. Ahmad Basri H. Basri Mohammed F.M. Abushammala Maulud K.N.A. 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1229-1238
Solid waste prediction is crucial for sustainable solid waste management. Usually, accurate waste generation record is challenge in developing countries which complicates the modelling process. Solid waste generation is related to demographic, economic, and social factors. However, these factors are highly varied due to population and economy growths. The objective of this research is to determine the most influencing demographic and economic factors that affect solid waste generation using systematic approach, and then develop a model to forecast solid waste generation using a modified Adaptive Neural Inference System (MANFIS). The model evaluation was performed using Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and the coefficient of determination (R2). The results show that the best input variables are people age groups 0-14, 15-64, and people above 65 years, and the best model structure is 3 triangular fuzzy membership functions and 27 fuzzy rules. The model has been validated using testing data and the resulted training RMSE, MAE and R2 were 0.2678, 0.045 and 0.99, respectively, while for testing phase RMSE =3.986, MAE = 0.673 and R2 = 0.98.Implications: To date, a few attempts have been made to predict the annual solid waste generation in developing countries. This paper presents modeling of annual solid waste generation using Modified ANFIS, it is a systematic approach to search for the most influencing factors and then modify the ANFIS structure to simplify the model. The proposed method can be used to forecast the waste generation in such developing countries where accurate reliable data is not always available. Moreover, annual solid waste prediction is essential for sustainable planning. 相似文献
995.
M.S. Abbassy H.Z. Ibrahim MM. Abu El‐Amayem 《Journal of environmental science and health. Part. B》2013,48(2):255-267
Abstract A study was conducted from summer 1995 to summer 1997 to assess the seasonal occurrence of pesticide residues and other organic contaminants, polychlorinated biphenyls (PCBs), in water at the estuaries of Rosetta and Damiatta branches of the Nile river. The results indicated that organochlorine compounds (OCs) including HCB, lindane, p,p‘‐DDE, p,p‘DDD, p,p‘‐DDT, aroclor 1254 and aroclor 1260 were present in all the water samples at concentration levels ranging between 0.195–0.240, 0.286–0.352, 0.035–0.067, 0.019–0.033, 0.024–0.031, 0.390–0.70 and 0.166–0.330 μg/l, respectively. The levels of these compounds were higher in water of Damiatta branch than those found in water of Rosetta branch. Aldrin, dieldrin and endrin were not detected in all water samples. Only 4 compounds from 36 organophosphorus insecticides, fungicides and s‐triazine herbicides tested were detected in water samples collected during summer and autumn seasons from Rosetta branch. The concentration levels of these detected compounds, dimethoate, malathion, captan, and ametryne, ranged from 0.011 to 0.340 μg/l, respectively. Similar compounds during the same seasons as found in water of Rosetta branch were also detected in water of Damiatta branch except ametryne. The levels of the detected compounds (dimethoate, malathion and captan) ranged between 0.030 and 0.330 μg/l. The levels of detected organophosphorus insecticides, fungicides and s‐triazine herbicides were in the order: dimethoate > malathion > captan > ametryne. 相似文献
996.
Sikandar I. Mulla Manjunatha P. Talwar Zabin K. Bagewadi Robertcyril S. Hoskeri Harichandra Z. Ninnekar 《Chemosphere》2013,90(6):1920-1924
Nitrotoluenes are the toxic pollutants of the environment because of their large scale use in the production of explosives. Biodegradation of such chemicals by microorganisms may provide an effective method for their detoxification. We have studied the degradation of 2-nitrotoluene by cells of Micrococcus sp. strain SMN-1 immobilized in various matrices such as polyurethane foam (PUF), sodium alginate (SA), sodium alginate–polyvinyl alcohol (SA–PVA), agar and polyacrylamide. The rate of degradation of 15 and 30 mM 2-nitrotoluene by freely suspended cells and immobilized cells in batches and fed-batch with shaken cultures were compared. The PUF-immobilized cells achieved higher degradation of 15 and 30 mM 2-nitrotoluene than freely suspended cells and the cells immobilized in SA–PVA, polyacrylamide, SA and agar. The PUF-immobilized cells could be reused more than 24 cycles without loosing their degradation capacity and showed more tolerance to pH and temperature changes than freely suspended cells. These results revealed the enhanced rate of degradation of 2-nitrotoluene by PUF-immobilized cells of Micrococcus sp. strain SMN-1. 相似文献
997.
Asha B. Chelani M.Z. Hasan 《Journal of the Air & Waste Management Association (1995)》2013,63(7):805-810
Abstract In this study, an artificial neural network is employed to predict the concentration of ambient respirable particu-late matter (PM10) and toxic metals observed in the city of Jaipur, India. A feed-forward network with a back-propagation learning algorithm is used to train the neural network the behavior of the data patterns. The meteorological variables of wind speed, wind direction, relative humidity, temperature, and time are taken as input to the network. The results indicate that the network is able to predict concentrations of PM10 and toxic metals quite accurately. 相似文献
998.
C. B. Lopes P. Figueira D. S. Tavares Z. Lin A. L. Daniel-da-Silva A. C. Duarte J. Rocha T. Trindade E. Pereira 《Environmental science and pollution research international》2013,20(9):5963-5974
The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m3/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m3/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents’ Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results. 相似文献
999.
Z. J. U. Malley M. Taeb T. Matsumoto 《Environment, Development and Sustainability》2009,11(1):175-195
Sustainable agricultural development is a necessity for sustainable economic growth and social development in Africa. Sustainable
agriculture largely depends on how effective natural and environmental resources are managed and utilized; it also depends
on the security of continuous access to such resources. This research was aimed to look into trends in agricultural productivity,
examine the persistence of the environmental insecurity, analyze the relationship between the two, and explore their links
to the national development policies. The results are discussed in the context of relevance to national development policies
and their implications on the sustainability of agriculture and rural livelihoods security. Literature survey, records collection
from the stakeholders, village level participatory assessments (PAs), observations and questionnaire survey were tools used
for data collection. The study shows significant (P < 0.01) declines in cereal crop yields, cattle milk yield and cattle calving rate, and increasing cattle mortality rate.
Elements of environmental insecurity were found to account for decline in agricultural productivity; significant (P < 0.01) proportion (68%), of 266 households interviewed, reported land resources deterioration, declining soil fertility,
and increasing drought frequencies as the causes of their low productivity. Declined fertilizer consumption and increasing
variability in rainfall amount significantly (P < 0.01) accounted for 59% and 39%, respectively, of the variations observed in total annual production of rice and maize,
which are major cereals in the study area. This study recommends measures to improve soil productivity such as improved fertilizer
application and use of organic manures along with mineral fertilizers for maintaining soil productivity; education of farmers
on sustainable use and management of land resources; and pro-poor rural policies in agricultural development and environmental
governance.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
1000.
Wind-tunnel simulations and field experiments for dust transport by air show that deposition is predominant on the windward side of hills whereas sans deposition is mainly observed on the lee side. That and other aspects such as the existence of several deposition regimes depending on wind intensity call for theoretical explanations. We present some preliminary considerations leading to such a theoretical framework. 相似文献