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   165篇
  免费   1篇
教育   107篇
科学研究   32篇
各国文化   1篇
体育   17篇
综合类   3篇
信息传播   6篇
  2024年   3篇
  2023年   3篇
  2022年   4篇
  2020年   2篇
  2018年   3篇
  2016年   2篇
  2015年   13篇
  2014年   9篇
  2012年   10篇
  2011年   29篇
  2010年   5篇
  2008年   11篇
  2007年   12篇
  2006年   12篇
  2005年   11篇
  2004年   7篇
  2003年   1篇
  2002年   3篇
  2000年   3篇
  1999年   1篇
  1997年   1篇
  1994年   1篇
  1990年   3篇
  1989年   1篇
  1988年   3篇
  1986年   3篇
  1979年   1篇
  1926年   1篇
  1925年   6篇
  1924年   2篇
排序方式: 共有166条查询结果,搜索用时 15 毫秒
81.
据说夸一个姑娘,最好是夸她漂亮,如果不漂亮,可以夸她有气质,如果这也没有,可以说她善良,再不济,就说你真健康。很可惜,从小到大,这些美好的形容词都与我无关。大人们见到我,无一例外都会用非常夸张的语调对我爸妈说:“你家小孩学习真好!”“学习好”是一句魔咒,飘荡在我的整个青春期。当然“学习好”不是坏事,可一个姑娘在别人眼里如果只有“学习好”这个优点,个中滋味,一言难尽。  相似文献   
82.
83.
Acute myocardial Infarction is one of the major causes of morbidity & mortality in world and atherosclerosis is the major cause of ischemic heart disease. In order to determine the better clinical marker of atherosclerosis, we estimated serum low-density lipoprotein (LDL-C) and high sensitivity C-reactive protein (hsCRP). Hundred patients of myocardial infarction and 100 controls irrespective of age and sex were studied for these parameters over a period of 2 years. The statistical analysis showed that the serum hsCRP was significantly raised in myocardial infarction cases than controls (P < 0.01) but LDL-C was not (P > 0.05). We conclude that the serum hsCRP has better predictive value for risk of atherosclerosis.  相似文献   
84.
Meng L  Cai F  Zhang Z  Niu L  Jin Q  Yan F  Wu J  Wang Z  Zheng H 《Biomicrofluidics》2011,5(4):44104-4410410
A microfluidic device was developed to precisely transport a single cell or multiple microbubbles by introducing phase-shifts to a standing leaky surface acoustic wave (SLSAW). The device consists of a polydimethyl-siloxane (PDMS) microchannel and two phase-tunable interdigital transducers (IDTs) for the generation of the relative phase for the pair of surface acoustic waves (SAW) propagating along the opposite directions forming a standing wave. When the SAW contacts the fluid medium inside the microchannel, some of SAW energy is coupled to the fluid and the SAW becomes the leaky surface wave. By modulating the relative phase between two IDTs, the positions of pressure nodes of the SLSAW in the microchannel change linearly resulting in the transportation of a single cell or microbubbles. The results also reveal that there is a good linear relationship between the relative phase and the displacement of a single cell or microbubbles. Furthermore, the single cell and the microbubbles can be transported over a predetermined distance continuously until they reach the targeted locations. This technique has its distinct advantages, such as precise position-manipulation, simple to implement, miniature size, and noninvasive character, which may provide an effective method for the position-manipulation of a single cell and microbubbles in many biological and biomedical applications.  相似文献   
85.
Determination of amyloid β (Aβ) isoforms and in particular the proportion of the Aβ 1-42 isoform in cerebrospinal fluid (CSF) of patients suspected of Alzheimer's disease might help in early diagnosis and treatment of that illness. Due to the low concentration of Aβ peptides in biological fluids, a preconcentration step prior to the detection step is often necessary. This study utilized on-chip immunoprecipitation, known as micro-immunoprecipitation (μIP). The technique uses an immunosorbent (IS) consisting of magnetic beads coated with specific anti-Aβ antibodies organized into an affinity microcolumn by a magnetic field. Our goal was to thoroughly describe the critical steps in developing the IS, such as selecting the proper beads and anti-Aβ antibodies, as well as optimizing the immobilization technique and μIP protocol. The latter includes selecting optimal elution conditions. Furthermore, we demonstrate the efficiency of anti-Aβ IS for μIP and specific capture of 5 Aβ peptides under optimized conditions using various subsequent analytical methods, including matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), capillary electrophoresis, microchip electrophoresis, and immunoblotting. Synthetic Aβ peptides samples prepared in buffer and spiked in human CSF were analyzed. Finally, on-chip immunoprecipitation of Aβ peptides in human CSF sample was performed.  相似文献   
86.
Liu Z  Xiao L  Xu B  Zhang Y  Mak AF  Li Y  Man WY  Yang M 《Biomicrofluidics》2012,6(2):24111-2411112
Precisely controlling the spatial distribution of biomolecules on biomaterial surface is important for directing cellular activities in the controlled cell microenvironment. This paper describes a polydimethylsiloxane (PDMS) gradient-generating microfluidic device to immobilize the gradient of cellular adhesive Arg-Gly-Asp (RGD) peptide on poly (ethylene glycol) (PEG) hydrogel. Hydrogels are formed by exposing the mixture of PEG diacrylate (PEGDA), acryloyl-PEG-RGD, and photo-initiator with ultraviolet light. The microfluidic chip was simulated by a fluid dynamic model for the biomolecule diffusion process and gradient generation. PEG hydrogel covalently immobilized with RGD peptide gradient was fabricated in this microfluidic device by photo-polymerization. Bone marrow derived rat mesenchymal stem cells (MSCs) were then cultured on the surface of RGD gradient PEG hydrogel. Cell adhesion of rat MSCs on PEG hydrogel with various RGD gradients were then qualitatively and quantitatively analyzed by immunostaining method. MSCs cultured on PEG hydrogel surface with RGD gradient showed a grated fashion for cell adhesion and spreading that was proportional to RGD concentration. It was also found that 0.107–0.143 mM was the critical RGD concentration range for MSCs maximum adhesion on PEG hydrogel.  相似文献   
87.
触摸未来手机屏幕上的虚拟按键就像按下真正的按键那么真实。秘密:一个类似于让今天的手机振动的小发动机,以及一点意识上的骗术。[编者按]  相似文献   
88.
89.

Objectives

Pediatric fractures suspicious for abuse are often evaluated in emergency departments (ED), although corresponding diagnostic coding for possible abuse may be lacking. Thus, the primary objective of this study was to determine the proportion of fracture cases investigated in the ED for abuse that had corresponding International Classification of Diseases (ICD) codes documenting abuse suspicion. Additional objectives were to determine the proportion of these fractures with admission ICD abuse coding, and physician text diagnoses recording abuse suspicion in the ED and/or admission notes. Factors possibly associated with abuse-related ED ICD codes were also examined.

Methods

Children less than three years of age that presented primarily with a fracture to two large academic children's hospitals from 1997 to 2007 and were evaluated for suspicion of abuse by child protective services were included in this retrospective review. The main outcome measure was the proportion of the fracture cases that had abuse suspicion reflected in ED discharge ICD codes.

Results

Of the 216 eligible patients, only 23 (11.5%) patients had ED ICD codes that included the possibility of abuse. Forty-nine (22.7%) had the possibility for abuse documented by physicians as an ED discharge diagnosis. In addition, 53/149 (35.6%) of all admitted patients and 34/55 (61.8%) of confirmed abuse cases included abuse-related admission ICD coding. Female gender was found to be a factor associated with ED ICD abuse codes.

Conclusion

Current standards of ICD coding result in a significant underestimate of the prevalence of children assessed in the ED and hospital wards for possible and confirmed abusive fracture(s).  相似文献   
90.
Aim: To discuss the merits of "tubes treatment" for esophageal fistula (EF). Methods: A 66-year-old female who suffered from a bronchoesophageal and esophagothoratic fistula underwent a successful "three tubes treatment" (close chest drainage, negative pressure suction at the leak, and nasojejunal feeding tube), combination of antibiotics, antacid drugs and nu-tritional support. Another 55-year-old male patient developed an esophagopleural fistula (EPF) after esophageal carcinoma operation. He too was treated conservatively with the three tubes strategy as mentioned above towards a favorable outcome. Results: The two patients recovered with the tubes treatment, felt well and became able to eat and drink, presenting no complaint. Con-clusion: Tubes treatment is an effective basic way for EF. It may be an alternative treatment option.  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