全文获取类型
收费全文 | 304篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 8篇 |
环保管理 | 15篇 |
综合类 | 185篇 |
基础理论 | 48篇 |
污染及防治 | 37篇 |
评价与监测 | 5篇 |
社会与环境 | 8篇 |
出版年
2023年 | 3篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 8篇 |
2009年 | 9篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 12篇 |
2005年 | 4篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 9篇 |
1998年 | 5篇 |
1994年 | 4篇 |
1992年 | 3篇 |
1988年 | 3篇 |
1967年 | 5篇 |
1965年 | 4篇 |
1964年 | 3篇 |
1963年 | 9篇 |
1962年 | 4篇 |
1959年 | 6篇 |
1957年 | 4篇 |
1956年 | 5篇 |
1955年 | 7篇 |
1954年 | 5篇 |
1951年 | 6篇 |
1950年 | 6篇 |
1949年 | 2篇 |
1947年 | 2篇 |
1946年 | 3篇 |
1941年 | 5篇 |
1940年 | 7篇 |
1939年 | 5篇 |
1938年 | 2篇 |
1937年 | 7篇 |
1935年 | 2篇 |
1934年 | 2篇 |
1932年 | 5篇 |
1931年 | 2篇 |
1930年 | 3篇 |
1929年 | 3篇 |
1926年 | 2篇 |
1923年 | 3篇 |
1920年 | 4篇 |
1918年 | 2篇 |
1917年 | 2篇 |
1913年 | 2篇 |
排序方式: 共有307条查询结果,搜索用时 15 毫秒
251.
252.
Linking GIS-based models to value ecosystem services in an Alpine region 总被引:11,自引:1,他引:11
Planning frequently fails to include the valuation of public goods and services. This can have long-term negative economic consequences for a region. This is especially the case in mountainous regions such as the Alps, which depend on tourism and where land-use changes can negatively impact key ecosystem services and hence the economy. In this study, we develop a semi-automatic procedure to value ecosystem goods and services. Several existing process-based models linked to economic valuation methods are integrated into a geographic information system (GIS) platform. The model requires the input of a digital elevation model, a land-cover map, and a spatially explicit temperature dataset. These datasets are available for most regions in Europe. We illustrate the approach by valuing four ecosystem services: avalanche protection, timber production, scenic beauty, and habitat, which are supplied by the “Landschaft Davos”, an administrative district in the Swiss Alps. We compare the impacts of a human development scenario and a climate scenario on the value of these ecosystem services. Urban expansion and tourist infrastructure developments have a negative impact on scenic beauty and habitats. These impacts outweigh the benefits of the developments in the long-term. Forest expansion, predictable under a climate change scenario, favours natural avalanche protection and habitats. In general, such non-marketed benefits provided by the case-study region more than compensate for the costs of forest maintenance. Finally, we discuss the advantages and disadvantages of the approach. Despite its limitations, we show how this approach could well help decision-makers balance the impacts of different planning options on the economic accounting of a region, and guide them in selecting sustainable and economically feasible development strategies. 相似文献
253.
254.
Sabine Maritschnik Elisabeth Eva Kanitz Erica Simons Marina Höhne Heidelinde Neumann Franz Allerberger Daniela Schmid Ingeborg Lederer 《Food and environmental virology》2013,5(4):220-225
On October 12, 2012, the provincial public health directorate of Salzburg reported a suspected norovirus (NV) outbreak among guests of a wedding–reception. The investigation aimed to confirm the causative agent, to identify the mode of transmission and to implement appropriate preventive measures. A probable outbreak case was defined as a wedding guest with diarrhoea or vomiting with disease onset from 7 to 10 October 2012 and who consumed food at the wedding dinner prepared by a hotel in the province Salzburg on 6 October 2012. A confirmed outbreak case fulfilled the criteria of a probable outbreak case and had a laboratory-confirmed NV infection. We conducted a cohort-investigation among the wedding guests. The case definitions were fulfilled in 26 wedding guests (25 %) including 2 confirmed cases. Females were 3.2 times more likely to develop disease (95 % CI 1.4–7.2) as compared to males. A mushroom dish was found to be associated with disease risk among females (risk ratio 2.3, 95 % CI 1.2–4.3). Two of 2 tested case-patients and 6 of 14 kitchen workers tested were positive for NV GII.4 Sydney. One kitchen staff-member worked during the wedding dinner despite diarrhoea. No food safety training was documented for the employees and the kitchen staff’s restroom was lacking operational facilities for hand hygiene. We report the first investigated outbreak due to GII.4 Sydney, which was likely due to a symptomatic kitchen worker. Gender-specific eating behaviour may have posed female guests at higher risk of NV infection. 相似文献
255.
256.
Rolf Schmid 《Die Naturwissenschaften》1985,72(10):534-538
Major developments in Japanese biotechnology in 1984 are reviewed. Besides industry and academia, research associations (companies and governmental research institutions guided by ministries) carry out joint fundamental research in biotechnology. Another important long-range aspect is the Technopolis Concept, which aims at decentralizing research and technological activities. 相似文献
257.
258.
259.
Alison M. Barker Reitumetse Molotsane Caroline Müller Urs Schaffner Erich Städler 《Chemoecology》2006,16(4):209-218
Summary. The turnip sawfly Athalia rosae sequesters glucosinolates from its cruciferous host plants in the larval stage. Investigation of the chemosensory and behavioural
responses of adult A. rosae to glucosinolates and their volatile hydrolysis products, isothiocyanates, revealed that females detect glucosinolates by
contact chemoreception and isothiocyanates by antennal olfaction. In electroantennogram recordings, four isothiocyanates (allyl
[2-propenyl] isothiocyanate, benzyl isothiocyanate, butyl isothiocyanate and iberverin [3-methylthiopropyl isothiocyanate])
were active at all doses presented, including the lowest (0.1 μg), whilst the threshold for detection of three others, iberin
[3-methylsulphinylpropyl isothiocyanate], methyl isothiocyanate, and sulforaphane [4-methylsulphinylbutyl isothiocyanate],
was higher, at between 1 and 10 μg (source concentration of volatiles). Allyl isothiocyanate attracted experienced females
in a four-chambered olfactometer, whilst na?ve females showed no response. Allyl isothiocyanate also attracted mature females
to baited yellow water traps in field trials, although immature females were repelled at high isothiocyanate concentrations.
In laboratory behavioural bioassays the glucosinolates sinigrin (allyl [2-propenyl] glucosinolate) and sinalbin (p-hydroxybenzyl
glucosinolate), stimulated ovipositor probing in mature female A. rosae to an extent comparable to hot-water extracts of their host plants. These responses show that glucosinolates and isothiocyanates
play an important role in host finding and host recognition in A. rosae. 相似文献
260.
For the last 6 years, sonographic signs for excessive fluid accumulation in the backs of 10- to 12-week-old fetuses have been looked for prior to transabdominal chorionic biopsy. In 1400 pregnancies, subsequent karyotype analyses revealed 28 cases of Down syndrome. In 15 ( = 54 per cent), a large fluid cushion over most of the back had been documented at the time of biopsy. Only a few chromosomally normal fetuses with the same peculiarity were observed. The cushion was also present in fetuses with trisomies 18 and 13 , and in Turner syndrome. Systematic first-trimester screening for nuchal fluid accumulation seems to be a recommended method for the detection of Down syndrome and other chromosome anomalies in young pregnant women at low risk. It compares favourably with current methods of maternal serum screening performed at 16–18 weeks which require a higher number of invasive procedures. 相似文献