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   692篇
  免费   45篇
  国内免费   31篇
耳鼻咽喉   5篇
儿科学   43篇
妇产科学   6篇
基础医学   55篇
口腔科学   35篇
临床医学   89篇
内科学   126篇
皮肤病学   8篇
神经病学   34篇
特种医学   59篇
外科学   100篇
综合类   26篇
预防医学   82篇
眼科学   7篇
药学   73篇
中国医学   1篇
肿瘤学   19篇
  2022年   8篇
  2021年   16篇
  2020年   4篇
  2019年   6篇
  2018年   8篇
  2017年   9篇
  2016年   10篇
  2015年   9篇
  2014年   17篇
  2013年   32篇
  2012年   26篇
  2011年   33篇
  2010年   20篇
  2009年   26篇
  2008年   26篇
  2007年   40篇
  2006年   38篇
  2005年   23篇
  2004年   14篇
  2003年   17篇
  2002年   18篇
  2001年   23篇
  2000年   19篇
  1999年   20篇
  1998年   13篇
  1997年   21篇
  1996年   18篇
  1995年   15篇
  1994年   23篇
  1993年   20篇
  1992年   15篇
  1991年   15篇
  1990年   12篇
  1989年   21篇
  1988年   13篇
  1987年   14篇
  1986年   12篇
  1985年   11篇
  1984年   6篇
  1983年   4篇
  1982年   4篇
  1981年   13篇
  1980年   5篇
  1979年   5篇
  1978年   4篇
  1976年   4篇
  1975年   8篇
  1972年   7篇
  1969年   3篇
  1968年   3篇
排序方式: 共有768条查询结果,搜索用时 10 毫秒
1.
In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants ad modum Brånemark. After 24±3.5 months the patients were re‐examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant‐retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can 1 facilitate oral hygiene measures.  相似文献   
2.
The association between the outcome of 531 surgically treated retinal detachments (RD) and preoperative findings was studied by logistic univariate and multivariate analysis. The following factors were significantly, and negatively associated with the surgical results: 1) previous RD in the same eye, 2) pre-operative visual acuity less than 2/60, 3) cloudy ocular media and/or a poorly dilated pupil, 4) an RD area of more than three quadrants, and 5) no retinal breaks detected. In the multivariate analysis no significant association was found for 9 factors: open angle glaucoma, interval of more than 2 months between symptoms and surgery, aphakia, pre-operative hypotony, absence of demarcation lines, posterior retinal breaks, pre-operative proliferative vitreo-retinopathy, sex and age. The significant factors combined with aphakia were studied in all conceivable combinations. The estimated probability of failure varied between 4 and 93%, indicating that the most important factors were observed.  相似文献   
3.
Abstract Maxillary and mandibular anterior permanent teeth in 38 children aged 7–12 years were examined 2 × with an interval of 2 years to determine whether spontaneous facial/lingual tooth position changes were related to alterations of the widths of keratinized and attached gingiva and the clinical crown height. Measurements included dental plaque, gingival inflammation, probing depth, and width of keratinized and attached gingiva. In addition, study casts from the baseline and 2-year examinations were used to measure clinical crown height and tooth position. The results showed that significant alterations in the widths of the keratinized and attached gingiva took place when the teeth changed positions in facial or lingual directions. The changes in gingival widths could to some extent be coupled to changes in clinical crown height. In teeth moving lingually, the gingival widths increased and the clinical crown height decreased. In teeth moving facially, the gingival widths decreased, and the facial gingiva sometimes receded. These gingival alterations call for examination of the facial gingiva as part of the monitoring of the development of the permanent dentition.  相似文献   
4.
Neuroimaging in Pineal Tumors   总被引:4,自引:0,他引:4  
F Reis  MD  AV Faria  MD  PhD  VA Zanardi  MD  PhD  JR Menezes  MD  F Cendes  MD  PhD  LS Queiroz  MD  PhD 《Journal of neuroimaging》2006,16(1):52-58
BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.  相似文献   
5.
6.
Résumé L'évidement axillaire peut être envisagé soit à titre préventif et systématique dans la chirurgie du cancer ou à titre curatif dans les affections du contenu de la fosse axillaire. Sa réalisation opératoire doit tenir compte de la morphologie de la lame cellulo-adipeuse de l'aisselle, moulée autour du paquet vasculo-nerveux entouré de sa gaine et de l'importance de ses prolongements vers le creux sus-claviculaire, voie de passage des courants lymphatiques.La position opératoire du membre supérieur facilite l'abord de la base de la pyramide et l'exérèse totale de son contenu sans sacrifice cutané ou musculaire et sans séquelle motrice.Le repérage des divers éléments de la lame cellulo-adipeuse doit permettre à l'anatomo-pathologiste d'apprécier la localisation exacte des ganglions lymphatiques.  相似文献   
7.
Myotubular myopathy (MTM1) is an X-linked disease, characterized by severe neonatal hypotonia and generalized muscle weakness, with pathological features suggesting an impairment in maturation of muscle fibres. The MTM1 gene encodes a protein (myotubularin) with a phosphotyrosine phosphatase consensus. It defines a family of at least nine genes in man, including the antiphosphatase hMTMR5/Sbf1 and hMTMR2, recently found mutated in a recessive form of Charcot-Marie-Tooth disease. Myotubularin shows a dual specificity protein phosphatase activity in vitro. We have performed an in vivo test of tyrosine phosphatase activity in Schizosaccharomyces pombe, indicating that myotubularin does not have a broad specificity tyrosine phosphatase activity. Expression of active human myotubularin inhibited growth of S.pombe and induced a vacuolar phenotype similar to that of mutants of the vacuolar protein sorting (VPS) pathway and notably of mutants of VPS34, a phosphatidylinositol 3-kinase (PI3K). In S.pombe cells deleted for the endogenous MTM homologous gene, expression of human myotubularin decreased the level of phosphatidylinositol 3-phosphate (PI3P). We have created a substrate trap mutant which shows relocalization to plasma membrane projections (spikes) in HeLa cells and was inactive in the S.pombe assay. This mutant, but not the wild-type or a phosphatase site mutant, was able to immunoprecipitate a VPS34 kinase activity. Wild-type myotubularin was also able to directly dephosphorylate PI3P and PI4P in vitro. Myotubularin may thus decrease PI3P levels by down-regulating PI3K activity and by directly degrading PI3P.  相似文献   
8.
9.
10.
To express the core protein of HIV-1 of Chinese prevalent strain (HIV-1 (CN)) in Pichia pastoris, the fulllength gag gene was inserted into the secretory expression vector pHILS1. Linearized recombinant plasmid pHILGAG by Sail was electrotransformed into the yeast strain GS115, and the yeast transformants were identified by PCR. To induce the interest protein to be expressed, the PCR positive transformants were inoculated in the medium of BMGY and BMMY, mRNA of the strain was detected by RT-PCR, and the expressed protein was analyzed by SDS-PAGE, Western blotting and thin layer scanning. mRNA (1.3 kb) was amplified by RT-PCR. SDS-PAGE and Western blotting analysis showed that the molecular mass of the expressed protein was 55 kD, which was similar to the expected value, and the expressed protein could react with McAb to HIV-1 p24. Thin layer scanning analysis demonstrated that the whole amount of the expressed protein was approximately 13 % of the soluble protein in the supernatant. The recombinant yeast had good genetic stability. The optimal expression conditions of the engineering yeast were as follows: BMMY medium, 80-90% of dissolved oxygen, 1% methanol, and 3-day-cultivation course. Gag proteins were expressed under the optimal expression condition and purified via gel filtration chromatography. The purity of the interest protein was up to 85 %. After the purified proteins were inoculated into BALB/c mice, the anti-HIV-1 antibodies in the immunized mice could be detected by Western blotting.  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