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   396篇
  免费   18篇
  414篇
  2023年   3篇
  2022年   2篇
  2021年   8篇
  2020年   9篇
  2019年   2篇
  2018年   6篇
  2017年   8篇
  2016年   12篇
  2015年   13篇
  2014年   23篇
  2013年   26篇
  2012年   30篇
  2011年   37篇
  2010年   15篇
  2009年   12篇
  2008年   30篇
  2007年   27篇
  2006年   25篇
  2005年   21篇
  2004年   22篇
  2003年   20篇
  2002年   20篇
  2001年   1篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1990年   2篇
  1988年   4篇
  1987年   1篇
  1986年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
排序方式: 共有414条查询结果,搜索用时 0 毫秒
131.
The amniotic membranes were collected from the placentae of selected and screened donors. Processing was done by washing the fresh amniotic membrane successively in sterile saline, 0.05% sodium hypochlorite solution and sterile distilled water until it was completely cleared of blood particles. The membranes were sterilized by gamma irradiation at 25 kGy. The processed amniotic membranes were applied to 50 open wounds comprising of 42 full thickness defects and eight partial thickness defects. These included leprotic, diabetic, traumatic, gravitational ulcers and superficial burn in the form of scald and corrosive burn. The radiation processed amniotic membranes favoured healing of unresponsive and non-healing ulcers of different etiologies. Ulcers with duration of minimum 3 weeks to maximum 12 months were found to heal in 2-6 weeks by the application of amniotic membranes.  相似文献   
132.
Post Kala-azar Dermal Leishmaniasis (PKDL) is a chronic but not life-threatening disease; patients generally do not demand treatment, deserve much more attention because PKDL is highly relevant in the context of Visceral Leishmaniasis (VL) elimination. There is no standard guideline for diagnosis and treatment for PKDL. A species-specific PCR on slit skin smear demonstrated a sensitivity of 93.8%, but it has not been applied for routine diagnostic purpose. The study was conducted to determine the actual disease burden in an endemic area of Malda district, West Bengal, comparison of the three diagnostic tools for PKDL case detection and pattern of lesion regression after treatment. The prevalence of PKDL was determined by active surveillance and confirmed by PCR based diagnosis. Patients were treated with either sodium stibogluconate (SSG) or oral miltefosine and followed up for two years to observe lesion regression period. Twenty six PKDL cases were detected with a prevalence rate of 27.5% among the antileishmanial antibody positive cases. Among three diagnostic methods used, PCR is highly sensitive (88.46%) for case confirmation. In majority of the cases skin lesions persisted after treatment completion which gradually disappeared during 6–12 months post treatment period. Reappearance of lesions noted in two cases after 1.5 years of miltefosine treatment. A significant number of PKDL patients would remain undiagnosed without active mass surveys. Such surveys are required in other endemic areas to attain the ultimate goal of eliminating Kala-azar. PCR-based method is helpful in confirming diagnosis of PKDL, referral laboratory at district or state level can achieve it. So a well-designed study with higher number of samples is essential to establish when/whether PKDL patients are free from parasite after treatment and to determine which PKDL patients need treatment for longer period.  相似文献   
133.
Plasmonics - The interplaying role of particle size and polymer layer thickness on the tunable optical response of polymer-coated Ag nanoparticles (NPs) has been studied experimentally and...  相似文献   
134.
MERIT40 (MEdiator of RAP80 Interaction and Targeting 40) is a novel associate of the BRCA1-complex and plays an essential role in DNA damage repair. It is the least characterized protein of BRCA1-complex and mainly responsible for maintaining the complex integrity. However, its structural and functional aspects of regulating the complex stability still remain elusive. Here, we carried out a comprehensive examination of MERIT40 biophysical properties and identified its novel interacting partner which would help to understand its role in BRCA1-complex. The recombinant protein was purified by affinity chromatography and unfolding pathway was determined using spectroscopic and calorimetric methods. Molecular model was generated using combinatorial approaches of modeling, and monomer–monomer docking was carried out to identify dimeric interface. Disordered region of MERIT40 was hatchet using trypsin and chymotrypsin to illustrate the existence of stable domain whose function was speculated through DALI search. Our findings suggest that MERIT40 forms a dimer in a concentration-independent manner. Its central region shows remarkable stability towards the protease digestion and has structural similarity with vWA-like region, a domain mainly present in complement activation factors. MERIT40 undergoes a three-state unfolding transition pathway with a dimeric intermediate. It interacts with adaptor molecule of BRCA1-complex, called ABRAXAS, thus help in extending the bridging interaction among various members which further stabilizes the whole complex. The results presented in this paper provide first-hand information on structural and folding behavior of MERIT40. These findings will help in elucidating the role of protein–protein interactions in stabilization of BRCA1-complex.  相似文献   
135.
Plasminogen activator inhibitor (PAI)-1 is a major fibrinolytic inhibitor. High PAI-1 is associated with increased renal and cardiovascular disease risk. Previous studies demonstrated PAI-1 down-regulation by 1,25-dihydroxyvitamin D? (1,25(OH)?D?), but the molecular mechanism remains unknown. Here we show that exposure of mouse embryonic fibroblasts to TNFα or LPS led to a marked induction of PAI-1, which was blunted by 1,25(OH)?D?, NF-κB inhibitor or p65 siRNA, suggesting the involvement of NF-κB in 1,25(OH)?D?-induced repression. In mouse Pai-1 promoter a putative cis-κB element was identified at -299. EMSA and ChIP assays showed that TNF-α increased p50/p65 binding to this κB site, which was disrupted by 1,25(OH)?D?. Luciferase reporter assays showed that PAI-1 promoter activity was induced by TNFα or LPS, and the induction was blocked by 1,25(OH)?D?. Mutation of the κB site blunted TNFα, LPS or 1,25(OH)?D? effects. 1,25(OH)?D? blocked IκBα degradation and arrested p50/p65 nuclear translocation. In mice LPS stimulated PAI-1 expression in the heart and macrophages, and the stimulation was blunted by pre-treatment with a vitamin D analog. Together these data demonstrate that 1,25(OH)?D? down-regulates PAI-1 by blocking NF-κB activation. Inhibition of PAI-1 production may contribute to the reno- and cardio-protective effects of vitamin D.  相似文献   
136.
Type I interferons (IFNs) are potent regulators of normal hematopoiesis in vitro and in vivo, but the mechanisms by which they suppress hematopoietic progenitor cell growth and differentiation are not known. In the present study we provide evidence that IFN alpha and IFN beta induce phosphorylation of the p38 mitogen-activated protein (Map) kinase in CD34+-derived primitive human hematopoietic progenitors. Such type I IFN-inducible phosphorylation of p38 results in activation of the catalytic domain of the kinase and sequential activation of the MAPK-activated protein kinase-2 (MapKapK-2 kinase), indicating the existence of a signaling cascade, activated downstream of p38 in hematopoietic progenitors. Our data indicate that activation of this signaling cascade by the type I IFN receptor is essential for the generation of the suppressive effects of type I IFNs on normal hematopoiesis. This is shown by studies demonstrating that pharmacological inhibitors of p38 reverse the growth inhibitory effects of IFN alpha and IFN beta on myeloid (colony-forming granulocytic-macrophage) and erythroid (burst-forming unit-erythroid) progenitor colony formation. In a similar manner, transforming growth factor beta, which also exhibits inhibitory effects on normal hematopoiesis, activates p38 and MapKapK-2 in human hematopoietic progenitors, whereas pharmacological inhibitors of p38 reverse its suppressive activities on both myeloid and erythroid colony formation. In further studies, we demonstrate that the primary mechanism by which the p38 Map kinase pathway mediates hematopoietic suppression is regulation of cell cycle progression and is unrelated to induction of apoptosis. Altogether, these findings establish that the p38 Map kinase pathway is a common effector for type I IFN and transforming growth factor beta signaling in human hematopoietic progenitors and plays a critical role in the induction of the suppressive effects of these cytokines on normal hematopoiesis.  相似文献   
137.
An 18-year-old rhesus macaque (Macaca mulatta) developed ptosis of the left upper eyelid due to a mass that had first been observed 10 years previously. The 11 x 7 x 7-mm mass was surgically excised, and the ptosis resolved after 5 days. Histologic examination of the mass revealed two confluent cell populations. Most cells were spindle-shaped and were arranged in loose fascicles. Smaller numbers of cells had squamous differentiation. The spindle-shaped cells expressed smooth muscle actin. Cells with squamous differentiation did not express smooth muscle actin, but did, along with around half of the spindle-shaped cells, express pan-cytokeratin. On the basis of histologic and immunohistochemical findings, the mass was diagnosed as myoepithelioma. The neoplasm most likely originated from the palpebral lobe of the lacrimal gland, although accessory lacrimal gland origin could not be excluded. Recurrence of the neoplasm has not been observed 6 months after surgery.  相似文献   
138.
Summary A locally isolated oleaginous strain ofRhodotorula glutinis strain IIP-30 produced a growth associated extracellular emulsifying agent while utilizing glucose during fed batch fermentation under nitrogen limitation at 30°C and pH 4. 0. Similar optimum conditions were also noted for intracellular lipid accumulation.  相似文献   
139.
140.
The present study was aimed to find out whether a change in the alignment of the pyramid from the north-south axis causes any variation in the effects produced by it on plasma cortisol levels and markers of oxidative stress in erythrocytes of adult-female Wistar rats. Plasma cortisol and erythrocyte TBARS levels were significantly lower whereas erythrocyte GSH was significantly higher in rats kept in pyramid that was aligned on the four cardinal points--north, east, south and west, as compared to normal control rats. Although there was a significant difference in the plasma cortisol level between normal control group and the group of rats kept in randomly aligned pyramid, there was no significant difference between these two groups for the other parameters. Erythrocyte TBARS levels in the group of rats kept in the randomly aligned pyramid was significantly higher than that in the group kept in the magnetically aligned pyramid. The results suggest that the north-south alignment of the pyramid is crucial for its expected effects.  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