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   32781篇
  免费   3028篇
  国内免费   612篇
耳鼻咽喉   394篇
儿科学   693篇
妇产科学   467篇
基础医学   2088篇
口腔科学   540篇
临床医学   2405篇
内科学   3254篇
皮肤病学   232篇
神经病学   1176篇
特种医学   1243篇
外国民族医学   45篇
外科学   3281篇
综合类   4198篇
预防医学   2639篇
眼科学   420篇
药学   1765篇
  17篇
中国医学   690篇
肿瘤学   10874篇
  2024年   52篇
  2023年   561篇
  2022年   1323篇
  2021年   1564篇
  2020年   1387篇
  2019年   1271篇
  2018年   1279篇
  2017年   1197篇
  2016年   1315篇
  2015年   1275篇
  2014年   2334篇
  2013年   2314篇
  2012年   2015篇
  2011年   2200篇
  2010年   1844篇
  2009年   1739篇
  2008年   1566篇
  2007年   1675篇
  2006年   1481篇
  2005年   1202篇
  2004年   1004篇
  2003年   818篇
  2002年   695篇
  2001年   592篇
  2000年   547篇
  1999年   466篇
  1998年   371篇
  1997年   310篇
  1996年   289篇
  1995年   225篇
  1994年   199篇
  1993年   150篇
  1992年   146篇
  1991年   123篇
  1990年   99篇
  1989年   98篇
  1988年   114篇
  1987年   71篇
  1986年   52篇
  1985年   95篇
  1984年   62篇
  1983年   47篇
  1982年   58篇
  1981年   27篇
  1980年   43篇
  1979年   32篇
  1978年   26篇
  1977年   23篇
  1976年   10篇
  1974年   6篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
21.
The aim of this study was to examine the predictors of long-term survival (>24 months) in patients with gall bladder cancer. A retrospective review of 117 cases of gall bladder cancer resected between 1989 and 2000. The resections included 80 simple cholecystectomies and 37 extended procedures. Patients with survival >24 months (n=44) were compared with those having survival <24 months (n=73) for 17 prognostic factors. Overall median survival was 16 months with a 5-year survival of 27%. T status (P=.000) and adjuvant chemoradiotherapy (P=.001) were independent predictors of long-term survival. Survival advantage was seen in T3N+ve disease (P=.007) with extended procedures. Complete (R0) resection was attained in 30 patients with a 5-year survival advantage of 30% as compared with incomplete (R1) resection (P=.0002). Adjuvant chemoradiotherapy improved survival in simple cholecystectomy group (P=.0008) but no advantage was seen after extended procedures. Stage III (P=.001) and node-positive disease (P=.0005) had significant benefit with adjuvant therapy. Poor differentiation and vascular invasion were associated with poor long-term survival. R0 resection was associated with prolonged survival. Extended procedures improved survival in patients with T3N+ve disease. Addition of chemoradiotherapy made significant improvement in long-term survival in stage III and node-positive lesions and in patients undergoing simple cholecystectomy. R0 resection predicted long-term survival in gall bladder cancer. T3 N+ve disease had better survival after extended procedures. Adjuvant chemoradiotherapy improved survival in stage III and node-positive disease. Poor differentiation and vascular invasion were adverse predictors of survival.  相似文献   
22.
The aim of our study was to determine the incidence, timing, and severity of vaginal stenosis in patients with carcinoma of the cervix who had received pelvic and/or vaginal radiotherapy as part of their treatment. We also sought to determine if there were any predisposing factors for the development of stenosis. A retrospective chart review was undertaken for all the patients diagnosed with carcinoma of the cervix between January 1, 1990, and December 31, 2000 and treated with pelvic and/or vaginal radiation at Westmead Hospital. Since January 1, 1990, data regarding vaginal stenosis has been prospectively recorded on all the patients. Data collected included patient demographics, stage of disease, treatments administered, and incidence, timing, and severity of vaginal stenosis. One hundred and eighty-eight patients were treated. Mean age was 58.6 years. Thirteen percent of patients had stage IB disease, 45% had stage II disease, 39.5% had stage III disease, and 1.5% had stage IV disease. One hundred and seventy-nine patients returned for follow-up, and data regarding vaginal toxicity were available in 98%. Twenty-seven percent had grade 1 toxicity (partial stenosis or shortening but not complete occlusion), and 11% had grade 2 (complete occlusion). Stenosis of any grade was noted at a mean of 9.6 months and median of 7.5 months (range, 26 days-5.6 years) from completion of treatment. The only prognostic factor associated with increased risk of stenosis was age greater than 50 years (odds ratio 2.26). Vaginal stenosis is a common complication of pelvic and vaginal radiotherapy, occurring in 38% of patients. Stenosis occurs most often in the first year after treatment. Patients over the age of 50 are most at risk.  相似文献   
23.
Anemia has been associated with a poorer treatment response and reduced survival in women undergoing primary radiotherapy (RT) or radiochemotherapy for advanced cervical carcinoma. This study aimed to determine the influence of anemia on outcome in patients with cervical carcinoma undergoing adjuvant RT. Medical records were reviewed for 183 cervical cancer patients who had received adjuvant RT because of risk factors after radical surgery (n= 109) or inadequate primary surgery (simple hysterectomy; n= 74). Kaplan-Meier and Cox regression analyses were used to study hemoglobin levels before and during adjuvant RT in relation to recurrence-free and overall survival. Hemoglobin values > or =11 g/dL were considered normal, while those <11 g/dL indicated anemia. Hemoglobin levels before RT influenced significantly overall survival and recurrence-free survival across the whole group (overall survival--log rank(all patients)= 7.5; df = 1; P= 0.006). However, subgroup analysis showed that the observed difference was mainly due to the group of women who had undergone inadequate primary surgery (overall survival--log rank(inadequate surgery)= 10.8; df = 1; P= 0.001). Multifactorial regression analyses comparing hemoglobin before RT with grading and tumor stage confirmed the prognostic value of hemoglobin values. Maintaining normal hemoglobin values before and during adjuvant RT seems to be important, especially in patients who have had inappropriate simple hysterectomy, which may resemble a therapeutic situation.  相似文献   
24.
Palliative whole brain radiotherapy (WBRT) is often recommended in the management of multiple brain metastases. Allowing for WBRT waiting time, duration of the WBRT course and time to clinical response, it may take 6 weeks from the point of initial assessment for a benefit from WBRT to manifest. Patients who die within 6 weeks (‘early death’) may not benefit from WBRT and may instead experience a decline in quality of life. This study aimed to develop a prognostic index (PI) that identifies the subset of patients with lung cancer with multiple brain metastases who may not benefit from WBRT because of ‘early death’. The medical records of patients with lung cancer who had WBRT recommended for multiple brain metastases over a 10-year period were retrospectively reviewed. Patients were classified as either having died within 6 weeks or having lived beyond 6 weeks. Potential prognostic indicators were evaluated for correlation with ‘early death’. A PI was constructed by modelling the survival classification to determine the contribution of these factors towards shortened survival. Of the 275 patients recommended WBRT, 64 (23.22%) died within 6 weeks. The main prognostic factor predicting early death was Eastern Cooperative Oncology Group (ECOG) status >2. Patients with a high PI score (>13) were at higher risk of ‘early death’. Twenty-three per cent of patients died prior to benefit from WBRT. ECOG status was the most predictive for ‘early death’. Other factors may also contribute towards a poor outcome. With further refinement and validation, the PI could be a valuable clinical decision tool.  相似文献   
25.
尼莫地平联合卡维地洛治疗原发性高血压78例临床分析   总被引:1,自引:0,他引:1  
目的分析尼莫地平联合卡维地洛治疗原发性高血压的临床疗效。方法将150例原发性高血压随机分成两组,对照组给予尼莫地平治疗,治疗组在对照组治疗的基础上,加之卡维地洛。结果治疗组与对照组显效率分别为33.3%和26.4%,总有效率为88.5%和76.4%,两组相比具有显著性差异(P〈0.05)。结论尼莫地平联合卡维地洛治疗原发性高血压疗效更为显著。  相似文献   
26.
脾切除治疗原发性骨髓纤维化适应证的探讨   总被引:1,自引:0,他引:1  
目的:探讨脾切除治疗原发性骨髓纤维化的可行性及其效果。方法:回顾性分析我院2000年1月至2006年12月间收治的5例行脾切除治疗原发性骨髓纤维化的病人资料。结果:本组病人均行脾切除术,其中2例加行贲门周围血管离断术.术后发生脾窝积液1例,肺部感染1例。随访3月至5年,病人贫血状况、左上腹疼痛症状均得到缓解.生活质量得到改善。结论:脾切除对有适应证的原发性骨髓纤维化是可行的治疗手段,可明显改善病人的症状,提高生活质量。  相似文献   
27.
干燥综合征是一种以口眼干燥为特征,主要累及外分泌腺的弥漫性结缔组织病。其发病可能与病毒感染、遗传和性激素异常等多种因素有关,在这些因素的共同作用下,机体免疫异常,组织损伤。与该病关系较密切的病毒有EB病毒、丙型肝炎病毒、巨细胞病毒、反转录病毒等。病毒在干燥综合征的发病机制中可能起重要的作用。  相似文献   
28.
目的研究血清α-L-岩藻糖苷酶(AFU)对原发性肝癌的诊断意义。方法分别测定20例正常对照者、45例慢性乙型肝炎、40例肝硬化、50例转移性肝癌及35例原发性肝癌患者的血清AFU。结果原发性肝癌组的血清AFU浓度和阳性率显著高手其他各组。结论血清AFU对原发性肝癌的诊断有重要价值。  相似文献   
29.
Objective Self-expandable metallic stent (EMS) placement has been the first choice for dysphagia because of the certainty over its safety, low invasiveness, and immediate efficacy. However, there still remain some problems in relation to the EMS placement site and anticancer therapies before and after EMS placement. Methods: Consecutive 78 patients in whom EMS was placed due to the unresectable malignant stricture in the esophagus or cardia from July 1995 to August 2003 in our department were studied. Results: Gastroesophageal reflux was found in 5 of 8 patients after placement of conventional EMS for the stricture in the gastroesophageal junction. Meanwhile, acid and bile reflux into the esophagus were not detected by pH and bilirubin monitoring, respectively, in 6 patients after placement of the EMS with an anti-reflux mechanism for the stricture in the gastroesophageal junction. The median survival period of all patients after EMS placement was 123 days. The median survival period of 7 patients with radiotherapy only after EMS placement was 138 days and that of 17 patients with radiotherapy before EMS placement was 60 days, which was shorter than that of the former (p<0.05). On the other hand, the median survival period after hospital admission due to dysphagia of these 7 patients was longer than that of 17 patients with radiotherapy only before EMS placement, although, the difference was not significant. Conclusion: EMS with an antireflux mechanism is not commercially available in Japan and approval is urgently required. The indication of radiotherapy associated with EMS placement is to be studied further.  相似文献   
30.
A case of primary malignant melanoma in the mediastinum presenting as recurrent laryngeal nerve palsy is reported. Tissue biopsy at mediastinotomy yielded a diagnosis of malignant melanoma. The mass was fixed to the left aspect of the trachea and to the upper border of the left main bronchus and could not be removed surgically. Further extensive clinical and radiological investigations revealed no evidence of tumor elsewhere in the body.  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