首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   153篇
  免费   2篇
儿科学   3篇
基础医学   15篇
口腔科学   1篇
临床医学   51篇
内科学   27篇
皮肤病学   12篇
神经病学   3篇
外科学   17篇
综合类   1篇
预防医学   2篇
药学   21篇
肿瘤学   2篇
  2017年   1篇
  2014年   1篇
  2013年   3篇
  2010年   9篇
  2009年   4篇
  2008年   5篇
  2007年   3篇
  2006年   2篇
  2003年   3篇
  2002年   1篇
  2001年   4篇
  2000年   4篇
  1999年   4篇
  1998年   7篇
  1997年   12篇
  1996年   18篇
  1995年   8篇
  1994年   8篇
  1993年   6篇
  1992年   5篇
  1991年   7篇
  1990年   5篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1972年   1篇
  1971年   4篇
  1970年   1篇
  1968年   2篇
  1956年   2篇
排序方式: 共有155条查询结果,搜索用时 0 毫秒
151.
Modern assessment of posture and motion involves the use of wide bandwidth piezoresistive accelerometers. The direct current (DC) component allows for assessment of slow motion and change in position referring to the gravitational axis; the alternating current (AC) component, calibrated in g, represents acceleration along the sensitive axis of the device. A method study was designed to evaluate the division in DC and AC components, reliabilities, discrimination between conditions, and detection of types of physical activities. Recordings were made in 26 student participants for eight conditions: sitting, standing, lying supine, sitting and typing on a PC keyboard, walking, climbing stairs, walking downstairs, and cycling. This procedure was repeated in reversed order. A classification of physical activities according to the eight conditions (first trial) and based on four parameters, that is DC components trunk, thigh, and lower leg and AC component trunk, was correct in almost 100% of patterns, when applied to the second trial.  相似文献   
152.
The preferred solution conformation of the PRP-hexapeptide (Tyr-Val-Pro-Leu-Phe-Pro) and of some of its structural analogues was investigated by NMR- spectroscopy, spectrofluorimetry and computer simulation technic. It was found that the preferred conformation is characterized by cis′-conformation of Pro3 and the γ-turn on the Leu4-residue: for Val2 and Phe5 a β-structure seems to be privileged. In such a conformation Val2 and Leu4 residues occupy exactly the same positions in space as residues i and i+ 3 in an α-helix. It suggests that the PRP-hexapeptide can interact with receptor protein inducing or stabilizing its helical conformation by “knobs into holes” packing.  相似文献   
153.
In two in vitro models for evaluating antipsoriatic activity, dithranol (anthralin) and triacetoxyan-thracene were compared. Both compounds exhibited an about equal effect on oxygen consumption of surviving human skin. Dithranol, however, exerted a stronger inhibiting effect on gIucose-6-phos-phate dehydrogenase (G-6-PDH) activity of human skin homogenates.  相似文献   
154.
Objective The present study aimed to test whether exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phone base stations may have effects on salivary alpha-amylase, immunoglobulin A (IgA), and cortisol levels. Methods Fifty seven participants were randomly allocated to one of three different experimental scenarios (22 participants to scenario 1, 26 to scenario 2, and 9 to scenario 3). Each participant went through five 50-minute exposure sessions. The main RF-EMF source was a GSM-900-MHz antenna located at the outer wall of the building. In scenarios 1 and 2, the first, third, and fifth sessions were "low" (median power flux density 5.2 μW/m^2) exposure. The second session was "high" (2126.8 μW/m^2), and the fourth session was "medium" (153.6 μW/m^2) in scenario 1, and vice versa in scenario 2. Scenario 3 had four "low" exposure conditions, followed by a "high" exposure condition. Biomedical parameters were collected by saliva samples three times a session. Exposure levels were created by shielding curtains. Results In scenario 3 from session 4 to session 5 (from "low" to "high" exposure), an increase of cortisol was detected, while in scenarios 1 and 2, a higher concentration of alpha-amylase related to the baseline was identified as compared to that in scenario 3. IgA concentration was not significantly related to the exposure. Conclusions RF-EMF in considerably lower field densities than ICNIRP-gnidelines may influence certain psychobiological stress markers.  相似文献   
155.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号