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561.
The use of chemical dispersants to combat oil spills at sea: A review of practice and research needs in Europe 总被引:1,自引:0,他引:1
In order to better understand the practice of dispersant use, a review has been undertaken of marine oil spills over a 10 year period (1995-2005), looking in particular at variations between different regions and oil-types. This viewpoint presents and analyses the review data and examines a range of dispersant use policies. The paper also discusses the need for a reasoned approach to dispersant use and introduces past cases and studies to highlight lessons learned over the past ten years, focussing on dispersant effectiveness and monitoring; toxicity and environmental effects; the use of dispersants in low salinity waters; response planning and future research needs. 相似文献
562.
With both declining and ageing populations, countries are addressing the threats to their competitiveness by attracting more highly educated workers and by investing in human capital, especially through policies to increase the rates of participation by young people in tertiary education. As the population is still ageing, there are concerns over the affordability of state support for the elderly, their roles in society and the economy. Active and flexible lifestyles extend healthy life expectancy, so extending the length of the working life is increasingly seen as a way to ease the transition to an economy where an ageing population is affordable.Senior academic staff, exemplars of such post-industrial flexibility, have long been accommodated beyond the statutory retirement age. Their benign conditions of work; high private and social returns to experience and knowledge; and their high levels of those skills, labour power and other capacities which do not degenerate with age, combine to prolong the length of their effective working lives. Against this, as in other sectors, redundancies, voluntary severance and other schemes to reduce staffing have encouraged early retirement. Increased demand for higher education has driven changes in the lecturing labour mix, with increasing use of a peripheral workforce of both early career and retiring staff. This has seen semi-retirement within higher education evolving to stretch the period over which withdrawal takes place.In this context, the exploratory work reported here considers the initial responses by employers and trades unions in Scottish Higher Education to the abolition of the default retirement age and the introduction of ‘The Employment Equality (Repeal of Retirement Age Provisions) Regulations 2011’. 相似文献
563.
Mads Solgaard Thomsen Karen J. McGlathery Anna Christina Tyler 《Estuaries and Coasts》2006,29(3):465-473
We determined the distribution of macroalgae in Hog Island Bay, a shallow coastal lagoon in Virginia, USA, seasonally at 12
sites from 1998 to 2000 and at 3 representative sites from 2000 to 2002. We analyzed macroalgal biomass, taxonomic richness,
and abundance of two non-native species, the cryptic invaderGracilaria vermiculophylla and the conspicuousCodium fragile, with respect to season, location (mainland, mid lagoon, barrier island sites), and elevation (intertidal, subtidal). Taxonomic
richness, total algal biomass, and nonnative biomass peaked in the summer months when temperature and light availability were
highest. A few stress tolerant and ephemeral algae dominated the algal assemblage.G. vermiculophylla constituted 74% of the entire algal biomass, was the most abundant alga in all seasons, locations, and elevation levels,
and was positively correlated with taxonomic richness and abundance of filamentous species.Ulva curvata, Bryopsis plumosa, andC. fragile accounted for an additional 16% of the algal biomass. There are distinct habitats in Hog Island Bay that can be classified
into low diversity-low biomass regions near the mainland and barrier islands and high diversity-high biomass regions in the
open mid lagoon, where abundant shells for attachment and intermediate levels of water column nutrients and turbidity likely
create better growth conditions. Taxonomic richness and biomass were higher in subtidal than intertidal zones, presumably
due to lower desiccation stress. This study provides an example of how a single invasive species can dominate an entire assemblage,
both in terms of biomass (being most abundant in all seasons, locations, and tidal levels) and species richness (correlating
positively with epiphytic filamentous taxa). By adding hard-substratum structural complexity to a relatively homogenous soft-substratum
system,G. vermiculophylla increases substratum availability for attachment and entanglement of other algal species and enhances local diversity. Without
widespread and abundantG. vermiculophylla, taxa likePolysiphonia, Ceramium, Bryopsis, Ectocarpus, andChampia would likely be much less common. This study also highlights the importance of using DNA analysis of voucher specimens in
monitoring programs to accurately identify cryptic invaders. 相似文献
564.
Kara L. Webster Jason A. Leach Paul W. Hazlett Robert L. Fleming Erik J. S. Emilson Daniel Houle Kara H. Y. Chan Fariborz Norouzian Amanda S. Cole Jason M. O'Brien Karen E. Smokorowski Stephanie A. Nelson Shelagh D. Yanni 《水文研究》2021,35(4):e14109
The Turkey Lakes Watershed (TLW) study is a federal, interdepartmental study established in 1979 to investigate the effects of acid rain on terrestrial and aquatic ecosystems. The 10.5 km2 watershed, located in the Eastern Temperate Mixed Forest on the Canadian Shield, has been the site of multidisciplinary studies on biogeochemical and ecological processes conducted across plot to catchment scales. The whole-ecosystem investigative approach was adopted from the outset and has allowed research to evolve from its original (and continuing) acidification focus to include investigations on the effects of climate change, forest harvesting and other forest ecosystem perturbations. The extensive scientific and support infrastructure allows for collection of a comprehensive data record essential for understanding long-term environmental trends. Data include atmospheric deposition, meteorology, stream hydrology and chemistry, soil, pore and ground water properties, understory and overstory vegetation, lake and outflow physical and chemical properties, and aquatic macroinvertebrate and fish community composition and abundance. These data have contributed to over 400 published research papers and graduate theses. The watershed has also figured prominently in many continent-wide comparisons advancing fundamental watershed theory. The knowledge gained at TLW has influenced pollutant emission and natural resource management policies provincially, nationally and internationally. 相似文献