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   915篇
  免费   34篇
  国内免费   88篇
耳鼻咽喉   27篇
儿科学   8篇
妇产科学   8篇
基础医学   93篇
口腔科学   17篇
临床医学   97篇
内科学   345篇
皮肤病学   4篇
神经病学   25篇
特种医学   67篇
外科学   133篇
综合类   86篇
预防医学   16篇
眼科学   10篇
药学   23篇
中国医学   4篇
肿瘤学   74篇
  2023年   18篇
  2022年   40篇
  2021年   33篇
  2020年   33篇
  2019年   33篇
  2018年   22篇
  2017年   30篇
  2016年   34篇
  2015年   43篇
  2014年   63篇
  2013年   62篇
  2012年   40篇
  2011年   51篇
  2010年   41篇
  2009年   57篇
  2008年   54篇
  2007年   24篇
  2006年   51篇
  2005年   40篇
  2004年   27篇
  2003年   21篇
  2002年   24篇
  2001年   20篇
  2000年   10篇
  1999年   24篇
  1998年   14篇
  1997年   13篇
  1996年   7篇
  1995年   15篇
  1994年   4篇
  1993年   6篇
  1992年   9篇
  1991年   6篇
  1990年   8篇
  1989年   5篇
  1988年   9篇
  1987年   4篇
  1986年   4篇
  1985年   6篇
  1984年   2篇
  1983年   2篇
  1982年   7篇
  1981年   4篇
  1980年   6篇
  1979年   2篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
  1972年   2篇
  1969年   1篇
排序方式: 共有1037条查询结果,搜索用时 375 毫秒
1.
BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.  相似文献   
2.
目的 分析不同病理类型甲状旁腺功能亢进(PHPT)的临床表现特点。方法 回顾性分析1958-2005年北京协和医院收治经手术病理证实的280例PHPT患者的临床资料。按病理类型分为甲状旁腺腺瘤组208例,甲状旁腺增生组52例及甲状旁腺腺癌组20例。结果 腺癌组中男性高于另外2组(P〈0.05)。增生及腺癌组中骨畸形、骨软化比例较低,增生组骨吸收、病理性骨折比例低于腺瘤组;胃肠道症状、多饮多尿及泌尿系统病变在腺癌组中高于另外2组(P均〈0.05)。血总钙(TCa)、血游离钙离子(ICa)及24h尿Ca在腺癌组显著高于腺瘤组及增生组(P均〈0.01),在腺瘤组与增生组间差异无统计学意义(P〉0.05)。出现高钙危象的比例在腺癌组显著高于另外2组(P〈0.01)。腺癌组病灶重量高于增生组,腺瘤组病灶直径小于增生组(P均〈0.05)。结论 在本组病例中,腺癌组男性比例较高,泌尿系统病变更为多见,出现高钙危象的比例显著增高,术后复发的比例较高。增生组骨骼系统病变相对较轻,其病变甲状旁腺重量低于腺癌与腺瘤组。  相似文献   
3.
Summary To evaluate the potential effect of androgens on the development and growth of human colorectal adenomas, the prevalence and concentration of cytosolic androgen receptors (AR) were analysed in 26 adenomas and 19 samples of normal colonic mucosa by a hybrid ligand receptor-binding assay. AR were detected in 7 of the adenomas (26.9%), and in 6 of the normal mucosa samples (31.6%). In the adenomas, AR levels demonstrated were low, ranging from 6 to 31 fmol/mg cytosol protein, and dissociation constants (Kds) ranged from 0.17–2.7x10-9 M. Of 13 adenomas excised from men, 6 (46%) had positive receptor activity, whereas only 1 of 13 (7.7%) from women was positive (P=0.03, Fisher's exact test). There was no correlation between AR titre and patient age, or between adenoma size and histological type or degree of dysplasia. In normal mucosa, AR levels ranged from 7 to 33 fmol/mg and Kds ranges from 0.24–3.1x10-9 M. There was no significant difference between either AR prevalence or levels in the adenomas and normal mucosa. The sex difference was exclusive to the adenoma. Endogenous androgen may play a role in adenoma development early in the promotional process.  相似文献   
4.
李文波  陈炯  杜敏  雷春  汤厚阔 《腹部外科》2007,20(6):350-351
目的探讨胰岛细胞瘤的诊断和治疗方法。方法对我院2000年6月~2006年12月收治的胰岛细胞瘤16例的临床资料进行回顾性分析。结果本组16例经手术治疗,功能性胰岛细胞瘤13例术后血糖均恢复正常,非功能性细胞瘤3例术后腹部症状消失。术后发生并发症3例,经治疗后痊愈出院。结论术前、术中影像学检查可以提高手术切除率。手术切除胰岛细胞瘤可以获得满意效果。  相似文献   
5.
大型垂体瘤不同手术入路治疗的比较研究   总被引:1,自引:0,他引:1  
本文回顾性比较106例大型垂体瘤的开颅和经蝶手术治疗的比较。开颅组58例,经蝶组48例。开颅组肿瘤次全切除9例,大部切除48例,部分切除1例;经蝶组全切除35例,大部切除12例,部分切除1例。开颅组术后视力好转率71%,无变化12例,恶化3例。手术后偏盲好转率67%;经蝶组手术后视力好转率77%,无变化者11例,无1例恶化。手术后偏盲好转率93%。开颅组20例有额叶挫伤,其中1例并发脑内血肿,死亡4例。作者认为垂体腺瘤不长向鞍旁、海绵窦、前颅窝底和脚间池和肿瘤不呈瓶颈样生长者,都应优先考虑经蝶窦入路手术。  相似文献   
6.
Despite the common occurrence of pleomorphic adenoma of major salivary glands, intranasal pleomorphic adenoma are rare. We present a ease of pleomorphic adenoma of the nasal septum along with a brief review of literature. The histological nature of this lesion in comparison to other salivary gland tumours and the importance of an accurate diagnosis has been stressed.  相似文献   
7.
分析了60例垂体腺瘤的CT表现。1例垂体微腺瘤缺乏特异性征象,59例大腺瘤大多数表现典型,诊断依据为肿瘤位置和蝶鞍改变。垂体腺瘤的形态学表现无特异性。应加强对垂体瘤卒中和侵袭征象的认识。对成人鞍区肿瘤的鉴别诊断进行了简短讨论。  相似文献   
8.
目的 研究细胞角蛋白(CK)19、galectin(Gal)-3、HBME-1在甲状腺不同病变表达的特点及鉴别诊断中的应用价值。方法 应用免疫组织化学EnVision法检测了21例结节性甲状腺肿(结甲)、14例毒性甲状腺肿(甲亢)、15例甲状腺滤泡性腺瘤(腺瘤)、13例滤泡性癌、13例滤泡型乳头状癌及48例经典型乳头状癌中单克隆抗体CK19、Gal-3、HBME-1的表达。结果 甲状腺病变中3种标记表达均位于细胞质;CK19、Gal-3、HBME-1的表达在甲状腺良性病变(结甲、甲亢、腺瘤)大多为弱阳性或阴性,而滤泡性癌阳性明显增加、乳头状癌(滤泡型及经典型)大多为中、强阳性,3种标记在甲状腺不同病变的阳性表达率结甲为52.4%(11/21)、9.5%(2/21)、19.0%(4/21),甲亢为50.0%(7/14)、7.1%(1/14)、7.1%(1/14),腺瘤为60%(9/15)、13.3%(2/15)、13.3%(2/15),滤泡性癌为76.9%(10/13)、61.5%(8/13)、53.8%(7/13),滤泡型乳头状癌为:100%(13/13)、84.6%(11/13)、92.3%(12/13),经典型乳头状癌为100%(48/48)、93.8%(45/48)、95.8%(46/48);在甲状腺良性病变(结甲、甲亢、腺瘤)与恶性病变(滤泡性癌、乳头状癌)间3种标记差异均有显著性(P均=0.000);同时3种标记在滤泡样病变即腺瘤、滤泡性癌和滤泡型乳头状癌间亦有显著差异(CK19:P=0.038,Gal-3:P=0.001,HBME-1:P=0.000)。结甲有9例,甲亢有7例,腺瘤有6例3种标记均不表达,滤泡性癌仅有1例,而乳头状癌(滤泡型及经典型)没有病例3种标记均不表达,同一病例有2种以上阳性表达在结甲、甲亢、腺瘤、滤泡性癌、滤泡型乳头状癌和经典型乳头状癌中分别为14.2%(3/21)、21.4%(3/14)、20.0%(3/15)、69.2%(9/13)、92.3%(12/13)、100.0%(48/48),在甲状腺良性病变与恶性病变间以及滤泡样病变间差异亦有显著性(P=0.000)。结论 CK19、Gal-3、HBME-1的检测尤其是联合检测对甲状腺病变的诊断、鉴别诊断具有较高的实用价值。  相似文献   
9.
We have used an avidin-biotin immunoperoxidase technique to localise epithelial cadherin (E-cadherin), a calcium-dependent cell-cell adhesion molecule, in 107 paraffin-embedded sections from 93 patients consisting of 24 with colorectal adenoma, 55 with rectal carcinoma and 14 with liver metastases. The corresponding primary colorectal tumours were also studied in these cases. E-cadherin was expressed by normal colorectal epithelial cells with typical membranous staining at the intercellular junctions. Loss of normal membranous E-cadherin expression and presence of cytoplasmic staining were found frequently in adenomas larger than 1 cm (P<0.01), with high grade dysplasia and villous histology (P<0.01). In primary rectal cancers, loss of membranous expression correlated with high tumour grade. No correlation was seen with Dukes and Jass stage, local extramural spread and 5-year recurrence rate. Complete loss of membranous E-cadherin immunoreactivity was seen in 7/14 (50%) liver metastases in which 6/7 (86%) showed intense membranous E-cadherin immunoreactivity in the corresponding primary tumour. Our data indicate that changes in E-cadherin immunoreactivity and cellular localisation correlate with size, severe dysplasia in adenomas and tumour grade in carcinomas. However, there seems to be no correlation between loss of membranous E-cadherin immunoreactivity and the invasive and metastatic potential of the carcinomas.  相似文献   
10.
Summary Morphologic studies of pituitary neoplasms removed by surgery from 36 human patients revealed 8 chromophobe adenomas which differed clearly from the remaining tumors. The cytoplasm of the adenoma cells failed to stain with PAS, aniline blue, aldehyde fuchsin, aldehyde thionin, orange G or light green, but positively stained granules were found by using erythrosine or carmoisine. Immunoperoxidase technique disclosed the presence of prolactin in the cytoplasm of some adenoma cells. The adenoma cells exhibited distinct ultrastructural features such as well developed rough surfaced endoplasmic reticulum with Nebenkern formation, prominence of Golgi apparatus, presence of misplaced exocytosis as well as pleomorphism of secretory granules with a considerable variation of size ranging from 130 to 500 nm in diameter. Thus, by electron microscopy the adenoma cells showed a close resemblance to prolactin cells of the non-tumorous pituitary glands except for the reduced size and number of secretory granules.These chromophobe adenomas are regarded as representing a distinct pathological entity clearly distinguishable from other forms of pituitary neoplasms. In view of the morphologic findings and the elevation of blood prolactin level (measured in 3 patients) the term, sparsely granulated prolactin producing pituitary adenoma, appears to be the most appropriate one to designate these tumors.The authors wish to thank Dr. H. Friesen for providing the anti-human prolactin and Dr. L. A. Sternberger for the peroxidase-anti-peroxidase complex. The excellent technical assistance of Mrs. Gezina Ilse and Miss Nancy Macphail and the valuable secretarial help of Mrs. Maureen Rowling are appreciated.The work was supported in part by MA-552 grant of the Medical Research Council of Canada and by the St. Michael's Hospital Research Society.  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