全文获取类型
收费全文 | 3615篇 |
免费 | 30篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 66篇 |
废物处理 | 243篇 |
环保管理 | 271篇 |
综合类 | 387篇 |
基础理论 | 735篇 |
环境理论 | 6篇 |
污染及防治 | 1365篇 |
评价与监测 | 338篇 |
社会与环境 | 239篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 44篇 |
2022年 | 98篇 |
2021年 | 148篇 |
2020年 | 58篇 |
2019年 | 62篇 |
2018年 | 134篇 |
2017年 | 136篇 |
2016年 | 201篇 |
2015年 | 103篇 |
2014年 | 218篇 |
2013年 | 340篇 |
2012年 | 252篇 |
2011年 | 266篇 |
2010年 | 203篇 |
2009年 | 131篇 |
2008年 | 206篇 |
2007年 | 230篇 |
2006年 | 167篇 |
2005年 | 139篇 |
2004年 | 105篇 |
2003年 | 84篇 |
2002年 | 83篇 |
2001年 | 46篇 |
2000年 | 38篇 |
1999年 | 25篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1985年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1970年 | 2篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1965年 | 2篇 |
1964年 | 5篇 |
1962年 | 3篇 |
1959年 | 4篇 |
1958年 | 15篇 |
1957年 | 5篇 |
1955年 | 2篇 |
1937年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有3660条查询结果,搜索用时 0 毫秒
1.
Rocío Mariano-Jelicich Florencia Botto Paulina Martinetto Oscar Iribarne Marco Favero 《Marine Biology》2008,155(4):443-450
The degree of individual or gender variation when exploiting food resources is an important aspect in the study of foraging
ecology within a population. Previous information on non-breeding skimmers obtained through conventional methodologies suggested
sex-related differences in prey species. In this study, stable isotope techniques were used to investigate the intraspecific
segregation in diet and foraging habits of the Black Skimmer (Rynchops niger intercedens) at Mar Chiquita Coastal Lagoon (37°40′S, 57°22′W), Argentina. These results were compared with contemporary data on the
trophic composition obtained by conventional methodologies. Blood samples were taken from birds captured with mist-nets during
their non-breeding season. The isotopic signatures of skimmers showed a diet mainly composed of marine prey with some degree
of estuarine fish intake. When comparing diet between sexes, males showed enrichment in 15N compared to females, while no differences were observed in 13C. The use of mixing models revealed differences in the relative composition of prey in the diet of male and female skimmers.
This study highlights stable isotope analysis as a valuable tool to test inter-individual differences and sexual segregation
in trophic ecology of Black Skimmers as compared to conventional methodologies. The results show a trophic segregation in
the Black Skimmer during the non-breeding season that can be explained by differences in prey species and larger prey sizes
of male skimmers. Our findings have significant implications for conservation since any environmental change occurring at
wintering areas might have profound effects on several avian life-history traits, and could be different for males and females
due to trophic segregation. 相似文献
2.
María L. Pignata Martha S. Cañas Hebe A. Carreras Liliana Orellana 《Environmental management》1997,21(5):793-801
Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Córdoba city, Argentina. The study area receives
regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location
of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight
ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur,
soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur
content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical
variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless
condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to
others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in
a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins,
pigments, HPCD, and MDA as they are responsible for the major variability of data. 相似文献
3.
Gilberto C. Gallopín 《Environmental Modeling and Assessment》1996,1(3):101-117
Through a systems approach indicators are shown to have the nature of variables, adopting different values or states, while other associated terms allude to special meanings assigned to specific values of the indicators. Practical implications are discussed. The concept of situational indicators of sustainability is introduced, representing a non-numerical function of both “pressures” or “driving forces” and “state” variables. A cost-effective multi-tiered approach to situational indicators is proposed. The concept of situational indicators is shown to be a particular case of indicators of systems behavior. A general systems formulation of the problem of sustainability highlights the importance of indicators of systems behavior and the central role of models in their definition. 相似文献
4.
5.
The Science of Nature - 相似文献
6.
7.
8.
Behaviour of different lichen species as biomonitors of air pollution by PAHs in natural ecosystems 总被引:2,自引:0,他引:2
Six different species of lichens (Parmelia sulcata Tayl., Evernia prunastri (L.) Ach., Ramalina farinacea, Pseudevernia furfuracea (L.) Zopf., Usnea sp. and Lobaria pulmonaria (Schreb.) Hoffm.) were collected in two mountain valleys in Central Pyrenees: the Aspe and Aragon valleys. Two multivariate techniques have been applied with different purposes, ANOVA and Discriminant Analysis (DA), to evaluate the data. The PAHs spatial distribution was studied in the three more abundant and widespread species in the area: P. sulcata, E. prunastri (L.) Ach. and R. farinacea in terms of total PAHs, PAHs related to the combustion processes and toxicity. Different behaviour of each lichen species to trap PAHs was found, being P. sulcata the best one to monitor the most persistent PAHs of pyrogenic origin and E. prunastri the most appropriate to provide information about pyrogenic and petrogenic PAHs. Traffic was the most relevant influence in PAHs bioaccumulation in lichen species. 相似文献
9.
Concentrations of Potentially Toxic Metals in Urban Soils of Seville: Relationship with Different Land Uses 总被引:1,自引:0,他引:1
Ruiz-Cortés E Reinoso R Díaz-Barrientos E Madrid L 《Environmental geochemistry and health》2005,27(5-6):465-474
Fifty-two samples of surface soils were taken in the urban area of Seville, to assess the possible influence of different
land uses on their metal contents and their relationship with several soil properties. The samples corresponded to five categories
or land uses: agricultural, parks, ornamental gardens, riverbanks, and roadsides. Sequential extraction of metal according
to the procedure proposed by the former Community Bureau of Reference (BCR) was carried out, and pseudo-total (aqua regia soluble) metal contents were determined. Lower organic C, total N and available P and K contents were found in riverbank
samples, probably due to the lack of manuring of those sites, left in a natural status. In contrast, significantly higher
electrical conductivity was found in those sites, due to the tidal influence of the nearby Atlantic Ocean. Other land uses
did not show significant differences in the general properties. Concentrations of Cu, Pb and Zn, both aqua-regia soluble and sequentially extracted, were clearly higher in soils from ornamental gardens, whereas the concentrations in the
riverbank samples were slightly lower than the other categories. In contrast, other metals (Cd, Cr, Fe, Mn, Ni) were uniformly
distributed throughout all land uses. A strong statistical association is found among the concentrations of Cu, Pb, Zn and
organic C, suggesting that the larger contents of these metals in ornamental gardens are partly due to organic amendments
added to those sites more frequently than to other kinds of sites. Considering the conclusions of previous studies, heavy
traffic can also contribute to those `urban’ metals in urban soils. Periodic monitoring of the concentrations of urban metals
in busy city centres and of the quality of amendments added to soils of recreational areas are recommended. 相似文献
10.
Izaskun Zorita Joana Larreta Natalia Montero José Germán Rodríguez Javier Franco Ángel Borja 《Chemistry and Ecology》2013,29(5):432-445
Bioaccumulation and biological effects of pollution were assessed in mussels (Mytilus galloprovincialis) caged for one month at three sites in the Oiartzun estuary (south-eastern Bay of Biscay, Spain) with the aim of evaluating their usefulness within the investigative monitoring defined in the European Union Water Framework Directive (WFD). The highest concentrations of organic contaminants determined in mussels' tissue were detected towards the inner part of the estuary but no gradient pattern was found for metal bioaccumulation. Population fitness responses measured as condition index, stress on stress and gonad index were similar in all caged mussels and did not follow the organic pollution gradient. However, biomarkers determined at tissue, cell and protein level (histopathology, micronuclei frequency, malondialdehyde levels and vitellogenin-like protein levels) revealed a higher stress syndrome at the inner part of the estuary showing signs of genotoxicity, oxidative stress and endocrine disruption. Overall, the integrated chemical–biological approach in connection with mussel caging technique proved to be a useful tool to assess environmental pollution, allowing a better understanding of the cause–effect relationship within the investigative monitoring defined in the WFD. 相似文献