全文获取类型
收费全文 | 92篇 |
免费 | 0篇 |
国内免费 | 6篇 |
出版年
2017年 | 1篇 |
2014年 | 1篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2001年 | 1篇 |
1999年 | 10篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 10篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 6篇 |
1965年 | 4篇 |
1916年 | 1篇 |
排序方式: 共有98条查询结果,搜索用时 31 毫秒
61.
A. Bondeau D. W. Kicklighter J. Kaduk ThE. Participants OF. ThE. Potsdam NpP. Model Intercomparison 《Global Change Biology》1999,5(Z1):35-45
Estimates of the seasonal absorbed fraction of photosynthetically active radiation (FPAR) and net primary productivity (NPP) are compared among four production efficiency models (PEMs) and seven terrestrial biosphere models simulating canopy development. In addition, the simulated FPARs of the models are compared to the FASIR-FPAR derived from NOAA-AVHRR satellite observations. All models reproduce observed summergreen phenology of temperate deciduous forests rather well, but perform less well for raingreen phenology of savannas. Some models estimate a much longer active canopy in savannas than indicated by satellite observations. As a result, these models estimate high negative monthly NPP during the dry season. For boreal and tropical evergreen ecosystems, several models overestimate LAI and FPAR. When the simulated canopy does respond to unfavourable periods, the seasonal NPP is largely determined by absorbed photosynthetically active radiation (APAR). When the simulated canopy does not respond to unfavourable periods, the light use efficiency (LUE) influences the seasonal NPP more. However, the relative importance of APAR and LUE can change seasonally. 相似文献
62.
63.
V G Petrukhin Iu A Belaia K K Ivanov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1975,(5):78-82
A modified method of obtaining the purified K- and O-antigens of Sh. newcastle with the use of ultracentrifugation is described. Serologically individual K- and O-antigens were obtained and their chemical composition was studied. Polysaccharide of the K-antigen consisted of the galacturonic acid, galactose, glucose, rhamnose xylose and hexosamine; it contained no heptoses. The O-antigen contained galactose, glucose, mannose, rhamnose, heptose and hexosamine; in difference to K-antigen was equal to 150000--160000. Thus, the K- and the O-antigen differed not only in the electrophoretic and diffuse mobility and immunological specificity, but also in the chemical composition. 相似文献
64.
65.
66.
THE EARL OF CRANBROOK 《Biological journal of the Linnean Society. Linnean Society of London》1977,9(4):305-322
Two surveys based on otter hunt records showed a 40% fall in the otter population 1957–1967, arrested and in places reversed by 1971 save in the central Midlands. The possible causes of that decline and of its apparent continuation in the Midlands are discussed. While accepting those two surveys most conservationists have since then refused to accept or consider any evidence from otter hunts: the writer does not. Reports of the presence of otters by naturalists are shown plotted on a map and suggest that they are present in sufficient numbers and at a sufficient density over the whole of Great Britain, save the central Midlands, to ensure a recovery to the pre-1960 density. Positive evidence found by hunts in a number of places in which naturalists had found none suggest that negative evidence should be accepted with caution. 相似文献
67.
68.
69.
SHOUMITRO DEB HENRY KWOK MARCO BERTELLI LUIS SALVADOR‐CARULLA ELSPETH BRADLEY JENNIFER TORR JARRET BARNHILL FOR THE GUIDELINE DEVELOPMENT GROUP OF THE WPA SECTION ON PSYCHIATRY OF INTELLECTUAL DISABILITY 《World psychiatry》2009,8(3):181-186
Psychotropic medications are used regularly to manage problem behaviours among people with intellectual disabilities. This causes concern because often these medications are used out of their licensed indications in this context. The WPA Section on Psychiatry of Intellectual Disability has recently developed an evidence and consensus-based international guide for practitioners for the use of psychotropic medications for problem behaviours among adults with intellectual disabilities. This guide advises on assessment of behaviours, producing a formulation, initiation of treatment, assessment of out-come and adverse effects, follow-up arrangements, and possibility of discontinuation of treatment. 相似文献
70.
T N Nikolaeva A V Sanin Iu A Belaia 《Nauchnye doklady vysshe? shkoly. Biologicheskie nauki》1987,(6):17-22
The influence of live bacteria and antigenic preparations of virulent and avirulent stains of Shigella flexneri 2a on the endogenous splenic colony formation in murine hematopoietic cells has been studied. The different stimulating activity of live microbial cells of virulent and avirulent strains Shigella flexneri 2a and their antigenic preparations on the endogenous colony formation has been shown. The effect observed depends on the preparation doses and time of their administration before irradiation of the animals. The stimulating influence on the development of hemopoiesis endogenous foci may be conditioned by the action of heat-labile products of the live microbial cells and closely correlates with the virulence of strains studied. 相似文献