全文获取类型
收费全文 | 100篇 |
免费 | 5篇 |
国内免费 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有108条查询结果,搜索用时 78 毫秒
41.
The recent advances in digital medical imaging and storage in cloud are bringing about more demands for efficient and secure image retrieval and management. Typically, medical images are very sensitive to changes where any modifications in its content may bring about an erroneous medical diagnosis. Therefore, securing medical images is a very essential process and the major task is, the medical image must maintain their sensitive contents at the time of reconstruction. The proposed methodology executes a secure image encryption and search of medical images proficiently over encrypted image database without leaking any sensitive data. It also ensures medical data integrity by introducing an efficient recovery mechanism on ROI of the image. The proposed scheme obtains recovery information about the image from the ROI of the medical data and embeds it in the RONI region using IWT transform which act as a reversible watermarking. If any alterations or tampers are caused to ROI at the third-party end, then it can be identified and recovered from the obtained recovery data. Besides, the model also executes a Copyright protection scheme to locate the authorized users, who illegally duplicate and distribute the retrieved image to unauthorized entities. 相似文献
42.
Christian Dussault Véronique Pinard Jean-Pierre Ouellet Réhaume Courtois Daniel Fortin 《Proceedings. Biological sciences / The Royal Society》2012,279(1746):4481-4488
The impact of anthropogenic disturbance on the fitness of prey should depend on the relative effect of human activities on different trophic levels. This verification remains rare, however, especially for large animals. We investigated the functional link between habitat selection of female caribou (Rangifer tarandus) and the survival of their calves, a fitness correlate. This top-down controlled population of the threatened forest-dwelling caribou inhabits a managed forest occupied by wolves (Canis lupus) and black bears (Ursus americanus). Sixty-one per cent of calves died from bear predation within two months following their birth. Variation in habitat selection tactics among mothers resulted in different mortality risks for their calves. When calves occupied areas with few deciduous trees, they were more likely to die from predation if the local road density was high. Although caribou are typically associated with pristine forests, females selected recent cutovers without negative impact on calf survival. This selection became detrimental, however, as regeneration took place in harvested stands owing to increased bear predation. We demonstrate that human disturbance has asymmetrical consequences on the trophic levels of a food web involving multiple large mammals, which resulted in habitat selection tactics with a greater short-term fitness payoff and, therefore, with higher evolutionary opportunity. 相似文献
43.
44.
45.
M.W. Davis M.L. Spencer M.L. Ottmar 《Journal of experimental marine biology and ecology》2006,328(1):1-9
This study tested the hypothesis that acuity of behavioral responses to food odor in three commercially important species of marine fish would increase as juvenile length increased. Swimming activity among two size groups of fish was measured in the presence of a series of squid extract dilutions. Increased swimming activity in juvenile Pacific halibut Hippoglossus stenolepis Schmidt, walleye pollock Theragra chalcogramma Pallas, and sablefish Anoplopoma fimbria Pallas was stimulated above threshold concentrations of squid extract, expressed as dilution from full strength. Maximum chemosensory acuity was observed in smaller (8-14 cm total length, TL) Pacific halibut and walleye pollock, while larger sablefish (15-23 cm TL) continued to develop acuity. Response thresholds were highest (10− 3 dilution) in Pacific halibut, at intermediate levels (10− 4-10− 6 dilution) in walleye pollock and smaller sablefish and reached the lowest levels (10− 13 dilution) in larger sablefish. The widely held view that dissolved free amino acids (DFAA) are the primary chemosensory stimulants for fish food searching may not be valid for sablefish, as they detected squid extract at dilutions containing DFAA that appeared to be far below ambient sea water DFAA concentrations. 相似文献
46.
Tom P. G. Van den Beuken Chris C. Duinmeijer Isabel M. Smallegange 《Journal of evolutionary biology》2019,32(2):153-162
Morphological structures used as weapons in male–male competition are not only costly to develop but are also probably costly to maintain during adulthood. Therefore, having weapons could reduce the energy available for other fitness‐enhancing actions, such as post‐copulatory investment. We tested the hypothesis that armed males make lower post‐copulatory investments than unarmed males, and that this difference will be most pronounced under food‐limited conditions. We performed two experiments using the male‐dimorphic bulb mite Rhizoglyphus robini, in which males are either armed “fighters” or unarmed “scramblers.” Firstly, we tested whether fighters and scramblers differed in their reproductive output after being starved or fed for 1 or 2 weeks. Secondly, we measured the reproductive output of scramblers and fighters (starved or fed) after one, two or three consecutive matings. Scramblers sired more offspring than fighters after 1 week, but scramblers and fighters only sired a few offspring after 2 weeks. Scramblers also sired more offspring than fighters at the first mating, and males rarely sired offspring after consecutive matings. Contrary to our hypothesis, the fecundity of starved and fed males did not differ. The higher reproductive output of scramblers suggests that, regardless of nutritional state, scramblers make larger post‐copulatory investments than fighters. Alternatively, (cryptic) female choice generally favours scramblers. Why the morphs differed in their reproductive output is unclear. Neither morph performed well relatively late in life or after multiple matings. It remains to be investigated to what extent the apparent scrambler advantage contributes to the maintenance and evolution of male morph expression. 相似文献
47.
48.
49.
50.