全文获取类型
收费全文 | 306篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 7篇 |
环保管理 | 18篇 |
综合类 | 107篇 |
基础理论 | 87篇 |
污染及防治 | 60篇 |
评价与监测 | 13篇 |
社会与环境 | 13篇 |
灾害及防治 | 2篇 |
出版年
2021年 | 5篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 10篇 |
2016年 | 5篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1961年 | 5篇 |
1959年 | 3篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1956年 | 2篇 |
1955年 | 5篇 |
1954年 | 4篇 |
1932年 | 1篇 |
1929年 | 1篇 |
1926年 | 1篇 |
1919年 | 1篇 |
排序方式: 共有311条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Quantifying disturbance effects on vegetation carbon pools in mountain forests based on historical data 总被引:2,自引:1,他引:1
Urs Gimmi Annett Wolf Matthias Bürgi Marc Scherstjanoi Harald Bugmann 《Regional Environmental Change》2009,9(2):121-130
Although the terrestrial carbon budget is of key importance for atmospheric CO2 concentrations, little is known on the effects of management and natural disturbances on historical carbon stocks at the
regional scale. We reconstruct the dynamics of vegetation carbon stocks and flows in forests across the past 100 years for
a valley in the eastern Swiss Prealps using quantitative and qualitative information from forest management plans. The excellent
quality of the historical information makes it possible to link dynamics in growing stocks with high-resolution time series
for natural and anthropogenic disturbances. The results of the historical reconstruction are compared with modelled potential
natural vegetation. Forest carbon stock at the beginning of the twentieth century was substantially reduced compared to natural
conditions as a result of large scale clearcutting lasting until the late nineteenth century. Recovery of the forests from
this unsustainable exploitation and systematic forest management were the main drivers of a strong carbon accumulation during
almost the entire twentieth century. In the 1990s two major storm events and subsequent bark beetle infestations significantly
reduced stocks back to the levels of the mid-twentieth century. The future potential for further carbon accumulation was found
to be strongly limited, as the potential for further forest expansion in this valley is low and forest properties seem to
approach equilibrium with the natural disturbance regime. We conclude that consistent long-term observations of carbon stocks
and their changes provide rich information on the historical range of variability of forest ecosystems. Such historical information
improves our ability to assess future changes in carbon stocks. Further, the information is vital for better parameterization
and initialization of dynamic regional scale vegetation models and it provides important background for appropriate management
decisions. 相似文献
85.
Gladbach A Gladbach DJ Kempenaers B Quillfeldt P 《Behavioral ecology and sociobiology》2010,64(11):1779-1789
Although studies on the evolution and function of female ornaments have become more numerous in the last years, the majority
of these studies were carried out in cases where female ornaments were a smaller and duller version of the ornaments found
in males. There are substantially fewer studies on species with female-specific ornaments. However, no study so far investigated
the potential of female-specific colouration as a quality signal in birds with conventional sex roles. We studied female-specific
ornamentation in a strongly sexually dichromatic species, the upland goose Chloephaga picta leucoptera, in two consecutive years. Male upland geese have white head and breast feathers and black legs, whereas females have reddish-brown
head and breast feathers and conspicuous yellow-orange legs. We found that female-specific colouration in upland geese can
reliably indicate different aspects of female phenotypic quality. Females with more orange coloured legs and more red-like
head colours had higher clutch and egg volumes than females with a paler leg and head colouration, and a more reddish plumage
colouration was related to a higher body condition. These relationships provide the theoretic possibility for males to assess
female phenotypic quality on the basis of colouration. Furthermore, the females with a more orange-like tarsus colouration
had higher plasma carotenoid levels. Both tarsus colouration and carotenoid concentrations of individual females were highly
correlated across years, indicating that tarsus colour is a stable signal. Despite this correlation, small individual differences
in plasma carotenoid concentrations between the two study years were related to differences in tarsus colouration. We thus
show for the first time in a wild bird and under natural conditions that carotenoid-based integument colouration remains consistent
between individuals in consecutive years and is also a dynamic trait reflecting individual changes in carotenoid levels. In
this species, where pairs form life-long bonds, the honesty of the carotenoid-based integument colouration suggests that it
may be a sexually selected female ornament that has evolved through male mate choice. 相似文献
86.
Anja Wolf Axel Bergmann Rolf-Dieter Wilken Xu Gao Yonghong Bi Hao Chen Christoph Schüth 《Environmental science and pollution research international》2013,20(10):7124-7139
This study deals with the evaluation of water quality of the Three Gorges Reservoir (TGR) in order to assess its suitability as a raw water source for drinking water production. Therefore, water samples from (1) surface water, (2) tap water, and (3) wastewater treatment plant effluents were taken randomly by 2011–2012 in the area of the TGR and were analyzed for seven different organic contaminant groups (207 substances in total), applying nine different analytical methods. In the three sampled water sources, typical contaminant patterns were found, i.e., pesticides and polycyclic aromatic hydrocarbons (PAH) in surface water with concentrations of 0.020–3.5 μg/L and 0.004–0.12 μg/L, disinfection by-products in tap water with concentrations of 0.050–79 μg/L, and pharmaceuticals in wastewater treatment plant effluents with concentrations of 0.020–0.76 μg/L, respectively. The most frequently detected organic compounds in surface water (45 positives out of 57 samples) were the pyridine pesticides clopyralid and picloram. The concentrations might indicate that they are used on a regular basis and in conjunction in the area of the TGR. Three- and four-ring PAH were ubiquitously distributed, while the poorly soluble five- and six-ring members, perfluorinated compounds, polychlorinated biphenyls, and polybrominated diphenyl ethers, were below the detection limit. In general, the detected concentrations in TGR are in the same range or even lower compared to surface waters in western industrialized countries, although contaminant loads can still be high due to a high discharge. With the exception of the two pesticides, clopyralid and picloram, concentrations of the investigated organic pollutants in TGR meet the limits of the Chinese Standards for Drinking Water Quality GB 5749 (Ministry of Health of China and Standardization Administration of China 2006) and the European Union (EU) Council Directive 98/83/EC on the quality of water intended for human consumption (The Council of the European Union 1998), or rather, the EU Directive on environmental quality standards in the field of water policy (The European Parliament and The Council of the European Union 2008). Therefore, the suggested use of surface water from TGR for drinking water purposes is a valid option. Current treatment methods, however, do not seem to be efficient since organic pollutants were detected in significant concentrations in purified tap water. 相似文献
87.
Heidi Van den Broeck Hans De Wolf Ronny Blust 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1791-1799
Metal (i.e. Ag, As, Ca, Cd, Co, Cu, Mn, Pb and Zn) and metallothionein (MT) concentrations in the soft tissue of Littorina littorea were measured along the heavily polluted Western Scheldt (WS) and relatively clean Eastern Scheldt (ES) estuary. Along the WS metal and MT levels in periwinkles reflected the known downstream decreasing pollution gradient. Surprisingly in ES animals As, Mn and Zn concentrations decreased from east to west reflecting past pollution. Compared to the WS metal concentrations of ES periwinkles were significantly lower and both estuaries were maximally discriminated from each other based on their Cd soft tissue concentration using a canonical discriminant analysis. Furthermore, no overall difference was found in MT levels among animals from both estuaries. Using previously obtained condition data (i.e. dry/wet weight ratio and lipid content) the relation between soft tissue metal concentration (i.e. Cd, Cu and Zn) and fitness indicators (i.e. MT and condition data) was examined using a canonical correlation analysis. Periwinkles with a high metal load (i.e. Cd and Zn) also had high MT levels but were in a relatively poor condition. 相似文献
88.
Anja Grawunder Dirk Merten Georg Büchel 《Environmental science and pollution research international》2014,21(11):6812-6823
The commonly observed enrichment of middle rare earth elements (MREE) in water sampled in acid mine drainage (AMD)-impacted areas was found to be the result of preferential release from the widespread mineral pyrite (FeS2). Three different mining-impacted sites in Europe were sampled for water, and various pyrite samples were used in batch experiments with diluted sulphuric acid simulating AMD-impacted water with high sulphate concentration and high acidity. All water samples independent on their origin from groundwater, creek water or lake water as well as on the surrounding rock types showed MREE enrichment. Also the pyrite samples showed MREE enrichment in the respective acidic leachate but not always in their total contents indicating a process-controlled release. It is discussed that most probably complexation to sulphite (SO3 2?) or another intermediate S-species during pyrite oxidation is the reason for the MREE enrichment in the normalized REE patterns. 相似文献
89.
90.
Petra Quillfeldt Javier Martínez Janos Hennicke Katrin Ludynia Anja Gladbach Juan F. Masello Samuel Riou Santiago Merino 《Die Naturwissenschaften》2010,97(9):809-817
Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular,
are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we
amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species,
including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic
species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a
determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative
importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative
analyses, systematic sampling and screening of vectors, and within-species comparisons. 相似文献