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   64篇
  免费   2篇
  2021年   3篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2015年   4篇
  2014年   7篇
  2013年   7篇
  2012年   10篇
  2010年   1篇
  2009年   3篇
  2008年   4篇
  2007年   4篇
  2006年   1篇
  2003年   2篇
  2000年   3篇
  1999年   2篇
  1997年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1986年   1篇
  1978年   1篇
  1973年   1篇
  1970年   2篇
  1968年   1篇
排序方式: 共有66条查询结果,搜索用时 546 毫秒
1.
The effect of three volatile anesthetics (halothane, enflurane, and isoflurane) on coronary flow and metabolic state of isolated rat hearts was studied. These anesthetics are coronary dilators and their effects are dose dependent. At 2 MAC (minimum alveolar concentration), isoflurane, enflurane, and halothane increase coronary flow by 114 +/- 5.9, 93 +/- 6.1, and 77 +/- 6.4%, respectively (p less than 0.001). At these concentrations, they also have a modest but significant metabolic effect causing a 30% reduction in myocardial ATP and phosphocreatine levels, with no significant modification in ADP and AMP concentrations. Energy charge and lactate/pyruvate ratio were also unaffected by these anesthetics. The vascular and metabolic effects were reversible within 2 and 30 min, respectively. Perfusion of the hearts with a Krebs-Henseleit solution without Pi did not interfere with the vascular and the metabolic effect of the anesthetics; however, in this case, ATP and phosphocreatine concentration did not return to control levels after their discontinuation despite full recovery of the vascular effect. These data suggest that the volatile anesthetics have direct coronary vascular and myocardial metabolic effects and that these effects occur independently.  相似文献   
2.
3.
Reactive oxygen species (ROS) are involved in many pathological processes through modifications of structure and activity of proteins. ROS also participate in physiological pathways such as thyroid hormone biosynthesis, which proceeds through oxidation of the prothyroid hormone (thyroglobulin, Tg) and iodide. Regarding the colloidal insoluble multimerized Tg (m-Tg), which bears dityrosine bridges and is present in the follicular lumen, a mild oxidative system generated different soluble forms of Tg, more or less compacted by hydrophobic associations, and linked with Grp78 and Grp94. In vitro, the combined action of ROS and PDI, in the presence of free glutathione (reduced/oxidized), increased the solubility of this misassembled Tg and partially restored the ability of Tg to synthesize hormones. Our results show that protein chaperones escape from the ER and are involved with ROS in thyroid hormone synthesis. Therefore, we propose a model of roles of m-Tg in the follicular lumen.  相似文献   
4.
5.
6.
7.
The efficient surface patterning of oligonucleotides was accomplished onto the inner wall of fused-silica capillary tubes as well as on the surface of glass slides through oxime bond formation. The robustness of the method was demonstrated by achieving the surface immobilization of up to three different oligonucleotide sequences inside the same capillary tube. The method involves the preparation of surfaces grafted with reactive aminooxy functionalities masked with the photocleavable protecting group, 2-(2-nitrophenyl) propyloxycarbonyl group (NPPOC). Briefly, NPPOC-aminooxy silane 1 was prepared and used to silanize the glass surfaces. The NPPOC group was cleaved under brief irradiation to unmask the reactive aminooxy group on surfaces. These reactive aminooxy groups were allowed to react with aldehyde-containing oligonucleotides to achieve an efficient surface immobilization. The advantage associated with the present approach is that it combines the high-coupling efficiency of oxime bond formation with the convenience associated with the use of photolabile groups. The present strategy thus offers an alternative approach for the immobilization of biomolecules in the microchannels of "labs on a chip" devices.  相似文献   
8.
9.
Much attractiveness research has focused on face shape. The role of masculinity (which for adults is thought to be a relatively stable shape cue to developmental testosterone levels) in male facial attractiveness has been examined, with mixed results. Recent work on the perception of skin color (a more variable cue to current health status) indicates that increased skin redness, yellowness, and lightness enhance apparent health. It has been suggested that stable cues such as masculinity may be less important to attractiveness judgments than short-term, more variable health cues. We examined associations between male facial attractiveness, masculinity, and skin color in African and Caucasian populations. Masculinity was not found to be associated with attractiveness in either ethnic group. However, skin color was found to be an important predictor of attractiveness judgments, particularly for own-ethnicity faces. Our results suggest that more plastic health cues, such as skin color, are more important than developmental cues such as masculinity. Further, unfamiliarity with natural skin color variation in other ethnic groups may limit observers' ability to utilize these color cues.  相似文献   
10.
Little is known about mate choice preferences outside Western, educated, industrialised, rich and democratic societies, even though these Western populations may be particularly unrepresentative of human populations. To our knowledge, this is the first study to test which facial cues contribute to African perceptions of African female attractiveness and also the first study to test the combined role of facial adiposity, skin colour (lightness, yellowness and redness), skin homogeneity and youthfulness in the facial attractiveness preferences of any population. Results show that youthfulness, skin colour, skin homogeneity and facial adiposity significantly and independently predict attractiveness in female African faces. Younger, thinner women with a lighter, yellower skin colour and a more homogenous skin tone are considered more attractive. These findings provide a more global perspective on human mate choice and point to a universal role for these four facial cues in female facial attractiveness.  相似文献   
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