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   110篇
  免费   3篇
基础医学   54篇
临床医学   13篇
内科学   23篇
神经病学   1篇
外科学   3篇
综合类   5篇
预防医学   4篇
药学   7篇
中国医学   3篇
  2023年   2篇
  2022年   9篇
  2021年   7篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   2篇
  2015年   4篇
  2014年   3篇
  2013年   8篇
  2012年   4篇
  2011年   5篇
  2010年   3篇
  2009年   8篇
  2008年   8篇
  2007年   9篇
  2006年   7篇
  2005年   8篇
  2004年   4篇
  2003年   2篇
  2002年   3篇
  2000年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1988年   2篇
  1983年   1篇
排序方式: 共有113条查询结果,搜索用时 0 毫秒
101.
目的 通过多次转模低成本批量制备弹性印章,并通过微接触印刷法制造纳米生物芯片.方法 利用SU-8模具制备PDMS二级模具,通过表面溅射Cr-Cu使PDMS印章与二级模具顺利脱模,并通过扫描电镜(SEM)观察模具的完整性.制备的印章通过微接触印刷法在玻片表面固定人lgG抗体,通过与纳米量子点(QD-605nm)标记的二抗反应,共同构建纳米生物芯片,通过荧光显微镜观察印刷图形的质量及印刷抗体的活性.结果 PDMS二级模具表面溅射Cr-Cu后能轻松地与PDMS印章脱模,且结构完整、图形清晰.弹性印章印刷IgG抗体形态清晰,量子点荧光强度好.结论 通过PDMS二级模具表面溅射Cr-Cu能够实现弹性印章的低成本批量制备,且该印章结合纳米量子点优异的荧光性能可制备高灵敏的生物芯片.  相似文献   
102.
To improve primary adult rat hepatocyte cultures, two types of PDMS microbioreactors containing a membrane, used as a scaffold for the attachment of cells, were built: one with a commercially-available polyester membrane, the other with a PDMS membrane (5 x 5 microm hole sizes) made in our laboratory. In that way, the relative surface area between blood perfusion and hepatocytes seen in vivo was mimicked and as cells were bathed in both sides by the culture medium they expressed much higher functions. A new technique to build such PDMS membrane was created. With this technique we could build various PDMS membranes with down to 5 x 5 microm holes and with thickness even below 20 microm. During the fifteen days of perfusion in these microbioreactors, good cell attachment then cell reorganization was observed. Moreover compared to static cultures in tissue-culture-treated dishes and in cultures in inserts with the same polyester membranes, seven and two times increases in the albumin secretion by the cultured primary rat adult hepatocyte were demonstrated, respectively. Ammonium removal also increased 7 times in perfused cultures compared to static cultures. These new microbioreactors, which closely mimic the in vivo liver architecture, revealed themselves to be very promising tools towards future applications in drug screening or liver tissue engineering.  相似文献   
103.
The flavor compounds of brines and fleur de sel collected in solar salterns from Saint-Armel (Brittany, France) were investigated by means of headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis in order to find elements to link the salt product and its area of production. A total of 58 volatile compounds were identified with considerable number of apparently carotenoid-derived compounds, i.e. norisoprenoids. Some of these could be considered as tracers to characterize products from Saint-Armel salterns. Indeed, 4 common compounds were detected in the different samples: 3,3,5,5-tetramethyl-cyclohexan-1-one, 4-(2,6,6-trimethyl-cyclohex-1-en-1-yl)-but-3-en-2-ol (β-ionol), 5,5,8a-trimethyloctahydro-2H-chromen-2-one and 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H)-benzofuran-1-one (dihydroactinidiolide). At the same time, preliminary studies were conducted to gain knowledge about microorganisms present in solar salterns, such as halophilic microalgae like Dunaliella salina, bacteria, fungi or yeasts. Some of these living organisms produce carotenoids, the starting material of some volatiles, and could either be responsible through their metabolisms for the generation of flavor compounds detected. Color attribute C* of the brine was closely positively correlated with the concentration of D. salina in the saline medium, linked to the concentration of viable and cultivable bacteria and highly correlated with the number of norisoprenoids detected.  相似文献   
104.
目的:分析比较不同固相萃取纤维头(PA,PDMS,PDMS-DVB)对白花蛇舌草挥发性成分的吸附性,并与传统的水蒸气蒸馏联用GS-MS(SD-GS-MS)方法进行比较。方法:采用PA,PDMS-DVB,PDMS 3种不同类型的固相微萃取纤维头以及水蒸气蒸馏法提取,联用GS-MS进行挥发性成分测定。结果:其中PA检测出50个成分,PDMS-DVB检测出51个,PDMS检测出18个。水蒸气蒸馏法检测出41个成分,与SPME法对比结果显示,相似度最高的为PA,共有成分为21个,其次为PDMSDVB 15个,PDMS 6个;有16个成分未在SPME法中检出。结论:HS-SPME-GS-MS方法可简便、高效地检测白花蛇舌草挥发性成分,但不能完全替代传统的水蒸气蒸馏联用GS-MS方法。  相似文献   
105.
以双酚A聚砜(PSF)为硬段、聚对羟基苯乙烯(PHS)为半硬段、聚二甲基硅氧烷(PDMS)为软段合成了三元多嵌段共聚物,并对其动态力学性能和抗张性能进行了比较详细的研究,结果表明该三元多嵌段共聚物为多相结构;在引入半硬段PHS后两相间的界面相增宽,粘接力增大,其强度和模量高且稳定,使含有机硅高分子材料强度低的弱点得以改善。扭辩分析(TBA)结果显示,这种三元多嵌段共聚物具有多重转变,且在-20℃至50℃间有两个较大的几乎重叠的吸收峰;这表明这种三元多嵌段共聚物的相分离结构较为复杂,并有良好的阻尼性能。  相似文献   
106.
The fabrication of microscopic 3-dimensional structures for directing and inducing cell proliferation, migration and differentiation is a prevailing goal in tissue engineering. We have developed microfluidic molding methods to generate proof-of-principle polyurethane microstructures containing holes as models of synthetic tissue scaffolds. Molding is achieved by injecting sub-milliliter quantities of polyurethane precursor into a network of capped polydimethylsiloxane microchannels. After curing of the polyurethane, the microchannels can be opened to release a solid polyurethane structure which replicates the structure of the microchannel network. The microchannels can be reused to generate many exact replicas which can be stacked. We were able to design stacks that mimic various bone architectures. 3-dimensional microtomographic images were used for the first time for visualization and quality control of the stacked microfabricated structures. The polyurethane structures are amenable to cell culture. This technology could potentially be applied to microfabricate implanTable 3-dimensional scaffolds of specified architecture and composition for tissue growth and regeneration.  相似文献   
107.
Microfabrication processes have changed the technology used in consumer goods, and have now advanced into applications in biology. Microfluidic platforms are microfabricated tools that are gaining popularity for studies of molecular and cellular biology. These platforms can allow precise control of the environment surrounding individual cells and they have been used to study physiologic and pharmacologic responses at the single-cell level. This article reviews microfluidic technology with emphasis on advances that could apply to the study of the nervous system, including architecture for isolation of axons, integrated electrophysiology, patterned physical and chemical substrate cues, and devices for the precisely controlled delivery of possible therapeutic agents such as trophic factors and drugs. The potential of these chips for the study of neurological diseases is also discussed.  相似文献   
108.
An air-molding technique for fabricating PDMS planar patch-clamp electrodes   总被引:3,自引:0,他引:3  
We present a new technique for fabricating planar patch electrodes in the laboratory. Planar electrodes are micromolded using a micron-sized stream of air to define an aperture in the silicone elastomer, polydimethylsiloxane (PDMS). We have previously demonstrated that planar PDMS electrodes make excellent patch electrodes after surface modification. We demonstrate single-channel measurements of the rSlo channel in Xenopus oocytes and whole-cell measurements in CHO and RBL mammalian cell lines, using planar PDMS electrodes.  相似文献   
109.
This paper describes the development and optimization of a low flow open-loop infusion device for continuous delivery of protein therapeutics. Specifically, a non-electronic polymer device is actuated with responsive hydrogels to infuse at 2 μL/hr for 12 hours. Hydrogel actuators transduce a chemical signal (change in pH of the local environment) into a mechanical response (swelling) generating the pressure to drive the infusion. The hydrogel actuators are separated from the drug reservoir by an elastomeric impermeable membrane. As the hydrogel actuators expand, the expansion deflects the flexible membrane down and reduces the volume of the drug reservoir causing the infusion of drug through the needle that is the only outlet for the reservoir.  相似文献   
110.
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