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   366篇
  免费   17篇
  国内免费   6篇
儿科学   5篇
妇产科学   11篇
基础医学   48篇
口腔科学   27篇
临床医学   21篇
内科学   39篇
皮肤病学   3篇
神经病学   32篇
特种医学   5篇
外科学   43篇
综合类   31篇
一般理论   1篇
预防医学   12篇
眼科学   2篇
药学   44篇
中国医学   6篇
肿瘤学   59篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   6篇
  2019年   6篇
  2018年   9篇
  2017年   8篇
  2016年   7篇
  2015年   13篇
  2014年   14篇
  2013年   21篇
  2012年   22篇
  2011年   23篇
  2010年   17篇
  2009年   18篇
  2008年   16篇
  2007年   25篇
  2006年   13篇
  2005年   15篇
  2004年   17篇
  2003年   21篇
  2002年   27篇
  2001年   27篇
  2000年   20篇
  1999年   13篇
  1998年   11篇
  1997年   5篇
  1996年   4篇
  1995年   3篇
  1994年   1篇
  1990年   1篇
  1988年   1篇
排序方式: 共有389条查询结果,搜索用时 234 毫秒
1.
2.
肺癌组织端粒酶活性测定   总被引:1,自引:0,他引:1  
①目的 探讨端粒酶作为肺癌诊断标记物的可行性及临床意义。②方法 用TRAP法检测 2 9例肺癌组织、2 7例癌旁组织和 35例正常组织标本中端粒酶活性表达。③结果  2 9例肺癌组织中 2 1例 (72 .4 % )端粒酶活性表达阳性 ,2 7例癌旁组织中 6例 (2 2 .2 % )端粒酶活性表达阳性 ,35例正常组织均不表达端粒酶活性。癌组织、癌旁组织与正常组织标本端粒酶活性比较有显著差异 (χ2 =34.0 13、3.937,P <0 .0 1、0 .0 5 )。④结论 端粒酶表达与肿瘤发生有关 ,其癌旁组织中端粒酶活性有可能成为判定肿瘤复发和预后的指标。  相似文献   
3.
银染端粒重复序列扩增法定量检测端粒酶活性的研究   总被引:1,自引:0,他引:1  
目的:探讨运用简便、快速及无放射性污染的银染粒重复序列扩增法(silver staining telomeric repeat amplification protocol,SS-TRAP)定量检测端粒酶活性。方法:运用SS-TRAP法检测了293细胞、经加热处理的293细胞、空白对照及典型乳腺癌组织、良性乳腺病变标本中端粒酶活性,其结果予以定量。结果:该法有检测出10个以上293细胞中端粒酶活性,热处理及空白对照均为阴性;乳癌组织标本中银染条带清晰可见,而良性病变中未见端粒酶阳性条带。结论:非核素银染TRAP法可用于端粒酶活性定量检测,与TRAP法相比,同样具有较高敏感性和特异性,但更快速、简便。  相似文献   
4.
Background: It is not well known how the immediate precursors of osteoclast develop into osteoclasts in the fetus. This ultrastructural-cytochemical study was designed to clarify the formation process of the osteoclasts and their increased activities in the fetal mouse limb buds after administration of high dose parathyroid hormone (PTH). Methods: Twenty-four or forty-eight hours after the high doses of PTH were injected into amniotic fluid of the pregnant C3H mice, the femoral limb buds of embryos were dissected out. Tartrate-resistant acid phosphatase (TRAP) reactions were performed while preparing specimens for electron microscopy. Results: Both control and PTH-given preosteoclasts and osteoclasts exhibited TRAP-positivities in dense bodies and vesicles. As effects of PTH, a binucleated preosteoclast of tandem fashion was observed. More osteoclastic hyperactivities were observed in the diaphyseal bone marrow. An osteoclast with a large cytoplasm exhibited two sets of clear zones and ruffled borders. Some osteoclasts demonstrated prominent amoeboid figures, while other osteoclasts developed large cytoplasmic vacuoles, which contained pieces of calcified chondroid bars. Conclusions: Our results revealed the progression of maturation from young preosteoclasts to osteoclasts. An existence of a peculiar binucleated preosteoclasts suggested one of the processes for multinucleation of the osteoclast. Quite remarkable osteoclastic hyperactivities were obviously the effects of high dose PTH. Our results also indicated the endophagocytic ability of the osteoclast. How PTH affected the osteoclasts and their precursors in the diaphyseal bone marrow can be speculated. © 1995 Wiley-Liss, Inc.  相似文献   
5.
BACKGROUND: The accuracy by which a number of newly described semen variables can predict either total fertilization failure (TFF) or pregnancy outcome in IVF, has not previously been investigated. The study aim was, therefore, to determine prospectively the predictive value of these variables. METHODS: The semen variables investigated were the post-wash total progressively motile sperm cell count (TPMC(post-wash)), the acrosome index (AI), 'cytoplasmic residues' and normal sperm morphology, evaluated according to the strict criteria ('strict criteria'), as well as the fast and slow total radical trapping antioxidant potential ('fast TRAP' and 'slow TRAP' respectively). RESULTS: The study group (n = 87) showed a mean (+/- SD) number of 10.2 +/- SD retrieved oocytes, 12.6% TFF, a mean fertilization rate of 59.7% and a pregnancy rate of 19.5% (17/87). TFF was significantly predicted by TPMC(post-wash), 'strict criteria', AI and 'cytoplasmic residues' (all P < 0.05). The outcome after embryo transfer was significantly predicted by AI and 'fast TRAP'. Semen samples with an AI <5% and a 'fast TRAP' <1.14 mmol/l in particular did not result in any pregnancies after IVF-embryo transfer. CONCLUSIONS: Of all the measured and calculated semen variables, TPMC(post-wash) was the best predictor of TFF, whilst AI and 'fast TRAP' were the best predictors of pregnancy after IVF.  相似文献   
6.
Pitfalls in TRAP assay in routine detection of malignancy in effusions   总被引:5,自引:0,他引:5  
Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.  相似文献   
7.
前列腺癌穿刺活检组织中端粒酶活性检测及意义   总被引:1,自引:0,他引:1  
目的;探讨前列腺穿刺活检标本中端粒酶(TE)活性检测在前列腺癌(PCA)诊断、鉴别诊断及评估PCA生物学行为中的意义。方法:应用端粒重复片段扩增法(TRAP法)检测疑为前列腺癌患者的前列腺穿刺活检标本的TE活性,并比较TE活性水平与PCA病理分化程度及转移情况的关系。结果:PCA组织中TE活性明显高于前列腺增生(BPH)组织。PCA组织中TE活性水平与其病理分化程度及转移情况相关。结论:PCA患者的前列有朱穿刺活检组织中的TE活性显著高于BPH者,且与其病理分化程度及转移情况相关。提示TE可能成为PCA早期诊断及鉴别诊断的一项新的分子瘤标,并可能与PCA的生物学行为相关。  相似文献   
8.
宫颈癌组织中端粒酶活性测定   总被引:4,自引:4,他引:0  
石梅  苏明权  杨秀芝  马海昕  张歌萌 《医学争鸣》2001,22(14):1321-1323
目的 探讨端粒酶活性在子宫颈癌组织发生发展中的作用及临床应用价值。方法 采用PCR-TRAP微孔杂交法检测45例子宫颈癌组织标本和8例正常的子宫颈组织的端粒酶活性。结果 45例宫颈癌组织中端粒酶阳性表达率为86.6%,其中宫颈癌Ⅰ期27例,阳性率77.7%,宫颈癌Ⅲ期6例,阳性率100%。8例正常宫颈组织中未检测出端粒酶阳性。结论 端粒酶活性表达在子宫颈癌的发生发展中起重要的作用,端粒酶活性检测对指导宫颈癌的诊断和治疗具有重要意义。  相似文献   
9.
端粒重复序列扩增-银染色法用于端粒酶活性测定的研究   总被引:9,自引:4,他引:5  
目的建立端粒重复序列扩增(TRAP)- 银染色技术,探讨端粒酶活性检测在肿瘤诊断中的意义。方法用裂解液提取组织细胞中的端粒酶模板,在特异引物作用下进行PCR 扩增,所得产物用氯仿∶异戊醇(24∶1)处理浓缩,作聚丙稀酰胺凝胶垂直板电泳,经硝酸银染色分析端粒酶活性。结果TRAP-银染色法能准确特异地检测小鼠骨髓瘤细胞(SP 2/0)的端粒酶活性,灵敏度可达 1×10  相似文献   
10.
端粒酶活性在人乳癌中的表达   总被引:2,自引:0,他引:2  
目的:比较端粒酶活性在乳腺良,恶性病变中的异同,探讨其在乳癌诊断中的意义和与普遍认定的预后指标间的关系。方法:用端凿重复扩增(TRAP)检测了54例乳腺癌、44例乳腺良性病变组织的端粒酶活性。结果:54例乳癌中49例(90.74%)显示端粒酶活性,1例纤维腺瘤有弱端粒酶活性。端粒酶活性与肿瘤大小及分期有关,而与腋淋巴结转移及雌,孕激素受体之间无关。结论:端粒酶活性见于绝大多数浸润性乳癌及极少数纤维  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