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   121065篇
  免费   10186篇
  国内免费   6703篇
耳鼻咽喉   1077篇
儿科学   3200篇
妇产科学   1882篇
基础医学   17942篇
口腔科学   2352篇
临床医学   11129篇
内科学   14705篇
皮肤病学   1675篇
神经病学   5951篇
特种医学   4599篇
外国民族医学   80篇
外科学   10744篇
综合类   22866篇
现状与发展   35篇
一般理论   1篇
预防医学   4924篇
眼科学   1674篇
药学   8481篇
  50篇
中国医学   3233篇
肿瘤学   21354篇
  2024年   293篇
  2023年   1560篇
  2022年   3361篇
  2021年   4503篇
  2020年   3769篇
  2019年   3464篇
  2018年   3242篇
  2017年   3668篇
  2016年   4191篇
  2015年   4458篇
  2014年   6681篇
  2013年   7737篇
  2012年   6592篇
  2011年   7733篇
  2010年   6307篇
  2009年   6356篇
  2008年   6616篇
  2007年   7124篇
  2006年   6640篇
  2005年   6089篇
  2004年   5399篇
  2003年   4608篇
  2002年   4142篇
  2001年   3766篇
  2000年   3116篇
  1999年   2711篇
  1998年   2339篇
  1997年   2034篇
  1996年   1608篇
  1995年   1430篇
  1994年   1147篇
  1993年   855篇
  1992年   681篇
  1991年   559篇
  1990年   454篇
  1989年   388篇
  1988年   355篇
  1987年   279篇
  1986年   227篇
  1985年   293篇
  1984年   248篇
  1983年   152篇
  1982年   209篇
  1981年   162篇
  1980年   101篇
  1979年   102篇
  1978年   72篇
  1977年   48篇
  1976年   42篇
  1975年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The case of a 75-year-old man with three synchronous carcinomas of the lung (large cell carcinoma, adenocarcinoma, and small cell carcinoma) is reported. This is the eighth well-documented case report in the literature; however, our case is the first to be reported with the newly described histological combination.  相似文献   
62.
We present herein the rare case of a young man who was found to have a solitary tumor in the right upper lobe of his lung by a routine chest X-ray. The tumor was removed by thoracoscopic surgery, and pathological examinations confirmed the diagnosis of a primary lymphangioma of the lung. A brief review of the available literature on this extremely rare type of benign tumor follows the case report.  相似文献   
63.
Cationic Lipid-Based Gene Delivery Systems: Pharmaceutical Perspectives   总被引:4,自引:0,他引:4  
Gene delivery systems are designed to control the location of administered therapeutic genes within a patient's body. Successful in vivo gene transfer may require (i) the condensation of plasmid and its protection from nuclease degradation, (ii) cellular interaction and internalization of condensed plasmid, (iii) escape of plasmid from endosomes (if endocytosis is involved), and (iv) plasmid entry into cell nuclei. Expression plasmids encoding a therapeutic protein can be, for instance, complexed with cationic liposomes or micelles in order to achieve effective in vivo gene transfer. A thorough knowledge of pharmaceutics and drug delivery, bio-engineering, as well as cell and molecular biology is required to design optimal systems for gene therapy. This mini-review provides a critical discussion on cationic lipid-based gene delivery systems and their possible uses as pharmaceuticals.  相似文献   
64.
胰腺肿瘤的B型超声诊断   总被引:4,自引:0,他引:4  
本文将资料完整的并经手术及病理证实的27例胰腺肿瘤初步小结。详细描述各例肿瘤的临床们诊与诊断、B型超声和手术情况,并重点讨论:临床们诊和B型超声未能检出的肿瘤,检出肿瘤大小较手术所见尺寸的要,10mm~40mm以及未见肿瘤浸润的原因。  相似文献   
65.
绝经后阴道出血852例临床分析   总被引:1,自引:0,他引:1  
探讨经经后阴道出血的原因,相关因素来指导临床实践。方法;对我院收治的852例绝经后阴道出血的临床资料进行回顾性分析。结果;以阴道炎最多269例、慢性宫颈炎188例,功能失调性子宫出血102例,宫内节育器98例,恶性肿瘤59例,以内膜癌 33例,卵巢恶性肿瘤次之16例。  相似文献   
66.
气管与主支气管肿瘤的影像诊断(附32例报告)   总被引:5,自引:1,他引:4  
作者对32例经病理证实的气管与主支气管良、恶性肿瘤的影像学表现进行分析,归纳为3型:腔内型、壁增厚型和腔内外型。后2种类型提示恶性,而无蒂的腔内型表现者不能鉴别良,恶性。作者还评价了常规体层、CT及MRI诊断气管与主支气管肿瘤的优、缺点,讨论了影像诊断的作用。  相似文献   
67.
The purpose of this study was to validate the hypothesis of neural histogenesis of Ewing's sarcoma of bone and related tumors by light microscopic, electron microscopic, and immunohistochemical analysis. We studied 32 round-cell sarcomas (19 cases of Ewing's sarcoma of bone, 3 extraskeletal Ewing's sarcomas, 5 peripheral primitive neuroectodermal tumors (PNET) and 5 cases of unclassified small round-cell type of neurogenic sarcoma (NS). Immunoreactivity for MIC2 was observed in all cases of Ewing's sarcoma and PNET, and in 1 cases of NS. Positive immunoreactivity for neural markers (NSE, synaptophysin, S-100) was found frequently in some tumors. Ultrastructurally, some specific features of neural differentiation, such as a fragmented basal lamina and neurosecretory granule-like particles, were found even in typical cases of Ewing's sarcoma of bone, which presented without a rosette arrangement and were almost negative for neural immuno-markers, but positive for MIC2. These ultrastructural neural features were observed less frequently in Ewing's sarcoma of bone than in PNET and NS. However, no significant correlation was demonstrated between the immunoreactivity for neural markers and the ultrastructural and histological neural features. These results support the hypothesis of a neural origin of Ewing's sarcoma and related neoplasms, and suggest that some overlapping entity could persist in PNET and Ewing's sarcoma and that this entity could be seen in histological and immunohistochemical studies of both tumors.  相似文献   
68.
经逆转录病毒载体将人GM-CSF基因导入人膀胱癌细胞株BIU-87细胞中,建立了转基因细胞株BIU/GM。经流式细胞仪行细胞DNA周期分析表明GM-CSF基因的导人及表达对BIU-87细胞的增长无影响。免疫荧光测定发现转GM-CSF基因及表达不能促进BIU-87细胞表面HLA-ABC、DR、DQ抗原的表达。转基因瘤细胞株经6000rad X射线照射灭活后,丧失增殖能力,逐步死亡,但能维持一定水平的GM-CSF分泌活性达两周以上。从而为制备灭活的转基因瘤苗提供了初步经验。  相似文献   
69.
This is a follow-up report on a male patient with a 46, Y, r(X) karyotype. Although he had no clinico-radiological features of X-linked recessive chondrodysplasia punctata (CDPX1), molecular studies revealed an Xp terminal deletion involving the putative region for the CDPX1 locus (PABX-DXS31). We suspect that the absence of CDPX1 may be attributable to the nature of the disease and the extreme short stature of the patient (mean – 5.6 S.D.). © 1993 Wiley-Liss, Inc.  相似文献   
70.
目的:探讨人卵巢癌标本中,肿瘤转移抑制基因nm23-H1编码蛋白NDPK-A表达的临床意义及其与预后的关系。方法:应用免疫组织化学抗生蛋白链菌素-过氧化酶结合(S-P)法,检测58例人卵巢癌标本中nm23-H1蛋白水平。结果:nm23-H1蛋白的表达与患者手术时是否有淋巴结及大网膜转移相关(P〈0.05),但原发灶与转移灶间的阳性表达率相差不显著;与患者术后生存时间密切相关(P〈0.01),术后生  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