全文获取类型
收费全文 | 715篇 |
免费 | 43篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 22篇 |
2012年 | 34篇 |
2011年 | 40篇 |
2010年 | 17篇 |
2009年 | 20篇 |
2008年 | 45篇 |
2007年 | 43篇 |
2006年 | 41篇 |
2005年 | 40篇 |
2004年 | 38篇 |
2003年 | 34篇 |
2002年 | 34篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 14篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1994年 | 6篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1976年 | 7篇 |
1974年 | 11篇 |
1973年 | 7篇 |
1969年 | 4篇 |
1962年 | 4篇 |
1958年 | 3篇 |
1951年 | 3篇 |
1931年 | 3篇 |
排序方式: 共有758条查询结果,搜索用时 390 毫秒
751.
752.
753.
754.
Hans W. Paerl Joseph R. Crosswell Bryce Van Dam Nathan S. Hall Karen L. Rossignol Christopher L. Osburn Alexandria G. Hounshell Randolph S. Sloup Lawrence W. HardingJr. 《Biogeochemistry》2018,137(3):307-320
Coastal North Carolina (USA) has experienced 35 tropical cyclones over the past 2 decades; the frequency of these events is expected to continue in the foreseeable future. Individual storms had unique and, at times, significant hydrologic, nutrient-, and carbon (C)-loading impacts on biogeochemical cycling and phytoplankton responses in a large estuarine complex, the Pamlico Sound (PS) and Neuse River Estuary (NRE). Major storms caused up to a doubling of annual nitrogen and tripling of phosphorus loading compared to non-storm years; magnitudes of loading depended on storm tracks, forward speed, and precipitation in NRE-PS watersheds. With regard to C cycling, NRE-PS was a sink for atmospheric CO2 during dry, storm-free years and a significant source of CO2 in years with at least one storm, although responses were storm-specific. Hurricane Irene (2011) mobilized large amounts of previously-accumulated terrigenous C in the watershed, mainly as dissolved organic carbon, and extreme winds rapidly released CO2 to the atmosphere. Historic flooding after Hurricanes Joaquin (2015) and Matthew (2016) provided large inputs of C from the watershed, modifying the annual C balance of NRE-PS and leading to sustained CO2 efflux for months. Storm type affected biogeochemical responses as C-enriched floodwaters enhanced air–water CO2 exchange during ‘wet’ storms, while CO2 fluxes during ‘windy’ storms were largely supported by previously-accumulated C. Nutrient loading and flushing jointly influenced spatio-temporal patterns of phytoplankton biomass and composition. These findings suggest the importance of incorporating freshwater discharge and C dynamics in nutrient management strategies for coastal ecosystems likely to experience a stormier future. 相似文献
755.
756.
757.
Yvonne Jackson William H. Dietz Charlene Sanders Lloyd J. Kolbe John J. Whyte Howell Wechsler Bruce S. Schneider Laura A. McNally Jean Charles-Azure Martina Vogel-Taylor Pamela Starke-Reed Van S. Hubbard Wendy L. Johnson-Taylor Ph.D. MPH R.D. Richard P. Troiano Karen Donato Susan Yanovski Robert J. Kuczmarski Lynne Haverkos Kathryn McMurry Randolph F. Wykoff Violet Woo Allan S. Noonan Jonelle Rowe Kathy McCarty Christine B. Spain 《Obesity (Silver Spring, Md.)》2002,10(12):1299-1305
Objective: To provide insight into discussions at the Surgeon General's Listening Session, “Toward a National Action Plan on Overweight and Obesity,” and to complement The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity. Research Methods and Procedures: On December 7 and 8, 2000, representatives from federal, state, academic, and private sectors attended the Surgeon General's Listening Session and were given an opportunity to recommend what to include in a national plan to address overweight and obesity. The public was invited to comment during a corresponding public comment period. The Surgeon General's Listening Session was also broadcast on the Internet, allowing others to view the deliberations live or access the archived files. Significant discussion points from the Listening Session have been reviewed by representatives of the federal agencies and are the basis of this complementary document. Results: Examples of issues, strategies, and barriers to change are discussed within five thematic areas: schools, health care, family and community, worksite, and media. Suggested cooperative or collaborative actions for preventing and decreasing overweight and obesity are described. An annotated list of some programmatic partnerships is included. Discussion: The Surgeon General's Listening Session provided an opportunity for representatives from family and community groups, schools, the media, the health-care environment, and worksites to become partners and to unite around the common goal of preventing and decreasing overweight and obesity. The combination of approaches from these perspectives offers a rich resource of opportunity to combat the public health epidemic of overweight and obesity. 相似文献
758.
Heat produced by hybridoma suspension cultures was continuously monitored in a two-liter heat-flux calorimeter. Heat measurements reflected changes in metabolic state of the culture under different aeration conditions. A highly anaerobic metabolism was indicated by the low ratios of heat produced to glucose consumed. 相似文献