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   367238篇
  免费   33309篇
  国内免费   25432篇
耳鼻咽喉   3299篇
儿科学   4200篇
妇产科学   5462篇
基础医学   43682篇
口腔科学   6349篇
临床医学   51266篇
内科学   54920篇
皮肤病学   3572篇
神经病学   19865篇
特种医学   13247篇
外国民族医学   224篇
外科学   35895篇
综合类   59539篇
现状与发展   88篇
一般理论   25篇
预防医学   24137篇
眼科学   10532篇
药学   37881篇
  381篇
中国医学   20954篇
肿瘤学   30461篇
  2024年   1153篇
  2023年   5514篇
  2022年   14251篇
  2021年   18056篇
  2020年   13494篇
  2019年   11919篇
  2018年   12473篇
  2017年   11209篇
  2016年   10405篇
  2015年   16073篇
  2014年   20075篇
  2013年   17920篇
  2012年   26437篇
  2011年   29598篇
  2010年   19083篇
  2009年   15011篇
  2008年   19933篇
  2007年   19912篇
  2006年   19727篇
  2005年   19087篇
  2004年   12324篇
  2003年   11268篇
  2002年   9770篇
  2001年   8471篇
  2000年   9127篇
  1999年   9570篇
  1998年   5790篇
  1997年   5802篇
  1996年   4560篇
  1995年   4139篇
  1994年   3410篇
  1993年   2202篇
  1992年   2990篇
  1991年   2573篇
  1990年   2241篇
  1989年   1973篇
  1988年   1663篇
  1987年   1461篇
  1986年   1202篇
  1985年   989篇
  1984年   583篇
  1983年   425篇
  1982年   270篇
  1981年   266篇
  1980年   221篇
  1979年   245篇
  1978年   107篇
  1977年   106篇
  1974年   116篇
  1973年   112篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Tendon healing is a complex process consisting of a large number of intricate pathways roughly divided into the phases of inflammation, proliferation, and remodeling. Although these processes have been extensively studied at a variety of levels in recent years, there is still much that remains unknown. This study used microarray analyses to investigate the process at a genetic level in healing rat Achilles tendon at 1, 7, and 21 days postinjury, roughly representing the inflammation, proliferation, and remodeling phases. An interesting temporal expression profile was demonstrated, identifying both known and novel genes and pathways involved in the progression of tendon healing. Both inflammatory response and pro-proliferative genes were shown to be significantly upregulated from 24 h postinjury through to 21 days. Day 7 showed the largest increase in genetic activity, particularly with the expression of collagens and other extracellular matrix genes. Interestingly, there was also evidence of central nervous system-like glutamate-based signaling machinery present in tendon cells, as has recently been shown in bone. This type of signaling mechanism has not previously been shown to exist in tendon. Another novel finding from these analyses is that there appears to be several genes upregulated during healing which have exclusively or primarily been characterized as key modulators of proliferation and patterning during embryonic development. This may suggest that similar pathways are employed in wound healing as in the tightly regulated progression of growth and development in the embryo. These results could be of use in designing novel gene-based therapies to increase the efficacy and efficiency of tendon healing.  相似文献   
102.
T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T‐cell activation. The levels of intercellular adhesion molecule‐1 (ICAM‐1, CD54) and L ‐selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L ‐selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme‐linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite‐extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long‐term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L ‐selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy.  相似文献   
103.
目的探讨肘、膝、踝关节内外翻畸形的治疗方式。方法对55例8~16岁的关节内、外翻畸形患儿(肘关节30例,膝15例,踝10例),采用肘外侧切口,踝、膝内外侧切口,截骨矫形,1枚或2枚“∩”形钉内崮定治疗,术后石膏托外固定4周,结果随访50例,随访时间3~24个月,截骨均达到骨性愈合,无一例发生感染,内固定松动临床疗效优48例(96%),良2例(4%)。结论用“∩”形钉作为截骨矫形内固定材料.具有操作简单、损伤小、效果好的优点。  相似文献   
104.
双侧内囊前肢毁损术治疗难治性强迫症疗效及随访研究   总被引:9,自引:0,他引:9  
目的 对难治性强迫症进行双侧内囊前肢毁损术治疗 ,评定手术疗效并进行 2年随访 ,以进一步探索脑外科手术对难治性强迫症的疗效 ,并探讨手术治疗的良好适应症。方法 对 2 8例难治性强迫症患者进行双侧内囊前肢毁损术治疗 ,并分别在手术前、手术后二周、手术后三月、手术后六月、手术后一年、手术后二年进行Y BOCS、HAMA、HAMD量表评定及术后疗效评定。结果  (1)强迫症患者手术后各期Y BOCS评分、HAMA评分与手术前比较均下降 ,有极显著差异 (P <0 .0 0 1) ;(2 )手术后各期Y BOCS的强迫思维评分均有明显下降 (P <0 .0 0 1) ,强迫行为在手术后 1年和 2年 ,与手术前比较无明显改变 (P >0 .0 5 ) ;(3)手术后 2年的总有效率为 5 3.5 % ,明显低于手术后 3月的总有效率 (P <0 .0 1)。结论 采用双侧内囊毁损术有相当的治疗效果 ,对于难治性强迫症患者可作为一种补充治疗手段 ;手术治疗对强迫行为的长期疗效较差 ,以严重的强迫思维为主的难治性强迫症患者为手术更好的适应症。  相似文献   
105.
Laryngeal tuberculosis: a review of 26 cases.   总被引:2,自引:0,他引:2  
OBJECTIVES: To review the clinical characteristics of laryngeal tuberculosis. STUDY DESIGN: Retrospective case series. SUBJECTS AND METHODS: Medical records of 26 histopathology-confirmed cases in a tertiary medical center from 1992 to 2006. RESULTS: The female patients were significantly younger than male patients. Hoarseness is the most common symptom (84.6%) because true vocal fold is most commonly involved (80.8%). Infection usually involves unilateral (66.7%) and right-side larynx but multiple subsites of the larynx (57.7%). The appearance of the affected larynx may have mixed features and change before diagnosis. Laryngeal tuberculosis is usually misdiagnosed as laryngeal cancer, especially in patients with malignant signs such as enlarged cervical lymph nodes and vocal fold immobility. Chest film is better than sputum examinations for screening. CONCLUSION: We should be especially alert about TB infection when facing young female patients with unusual laryngeal lesions. Extensive laser excision before diagnosis should be avoided because after antituberculous treatment, prognosis is usually good and vocal fold immobility could be reversible.  相似文献   
106.
107.
表皮生长因子及其受体与流产关系的探讨   总被引:4,自引:0,他引:4  
采用放射免疫竞争抑制饱和分析法,检测47例难免流产患者,65例人工流产及20例健康非孕妇女血清表皮生长因子(EGF)水平;同时采用免疫组织化学法检测流产者胚胎组织中表皮生长因子受体(EGFR)表达程度。结果:人工流产组血清EGF水平高于自然流产及非孕妇女,而自然流产与非孕妇女差异无显著性;胚胎组织中EGFR阳性表达率人工流产组明显高于自然流产组。提示:EGF通过与其受体结合对妊娠维持、胚胎及胎儿的  相似文献   
108.
小切口胆囊切除术108例临床观察   总被引:1,自引:0,他引:1  
本文报告腹部切口5-8cm的小切口胆囊切除术108例,与同期大切口胆囊切除术相比,具有创伤较小、恢复较快、并发症少、切口疤痕小的优点,虽不如腹腔镜胆囊切除术(LC)的疼痛轻、恢复快,但并症比LC少,只要适应症选择得当,在术者的经验和技术较成熟的情况下,不昔为一种可供选择的方法。  相似文献   
109.
In order to investigate the antagonistic effect of Glycyrrhiza Uralensis Fish (GUF) and Chelidonium maJus L (CML) on gastrccarcinogenesis induced by MNNG in Wastar rats, we treated the rats with MNNG alone (group 1) and with MNNG plus GUF and CML (group 2 and 3) respectively. The incidence of infiltrating adenocarcinoma of the glandular stomach and duodenum in group 2 was significantly lower than that in group 1 (26.7% vs. 67.8%). The differentiation and aggressivenees of carcinomas occured in group 2 were much better and mild than those in group 1. Present study also demonstrated that the inhibitory effect of CML on proliferation of human stomach carcinoma cell line MGC-803 was very remarkable; in addition, GUF and CML were able to antagonise the mutagenic activation of MNNG. These results suggest that GUF and CML may be empoyed in prevention of gastric carcinoma.  相似文献   
110.
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