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   28430篇
  免费   2432篇
  国内免费   1444篇
耳鼻咽喉   516篇
儿科学   259篇
妇产科学   371篇
基础医学   1743篇
口腔科学   196篇
临床医学   2433篇
内科学   4563篇
皮肤病学   191篇
神经病学   489篇
特种医学   1629篇
外国民族医学   43篇
外科学   4031篇
综合类   5518篇
现状与发展   4篇
预防医学   668篇
眼科学   74篇
药学   1101篇
  4篇
中国医学   243篇
肿瘤学   8230篇
  2024年   13篇
  2023年   337篇
  2022年   455篇
  2021年   923篇
  2020年   916篇
  2019年   805篇
  2018年   746篇
  2017年   833篇
  2016年   1125篇
  2015年   1059篇
  2014年   1678篇
  2013年   1400篇
  2012年   1510篇
  2011年   1706篇
  2010年   1466篇
  2009年   1594篇
  2008年   1617篇
  2007年   1857篇
  2006年   1798篇
  2005年   1532篇
  2004年   1363篇
  2003年   1161篇
  2002年   1033篇
  2001年   1001篇
  2000年   794篇
  1999年   576篇
  1998年   481篇
  1997年   423篇
  1996年   303篇
  1995年   297篇
  1994年   278篇
  1993年   175篇
  1992年   168篇
  1991年   175篇
  1990年   115篇
  1989年   85篇
  1988年   69篇
  1987年   66篇
  1986年   67篇
  1985年   68篇
  1984年   39篇
  1983年   31篇
  1982年   45篇
  1981年   27篇
  1980年   30篇
  1979年   23篇
  1978年   13篇
  1977年   15篇
  1976年   7篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
The association between Barrett's esophagus (BE) and a personal or family history of cancer other than gastroesophageal remains unknown. To evaluate the effect of personal and family history of certain cancers and cancer treatments on the risk of BE, we analyzed data from a Veterans Affairs case‐control study that included 264 men with definitive BE (cases) and 1486 men without BE (controls). Patients with history of esophageal or gastric cancer were excluded. Patients underwent elective esophagogastroduodenoscopy or a study esophagogastroduodenoscopy concurrently with screening colonoscopy to determine BE status. Personal and family history of several types of cancer was obtained from self‐reported questionnaires, supplemented and verified by electronic medical‐record reviews. We estimated the association between personal and family history of cancer or radiation/chemotherapy, and BE. Personal history of oropharyngeal cancer (1.5% vs. 0.4%) or prostate cancer (7.2% vs. 4.4%) was more frequently present in cases than controls. The association between BE and prostate cancer persisted in multivariable analyses (adjusted odds ratio 1.90; 95% confidence interval 1.07–3.38, P = 0.028) while that with oropharyngeal cancer (adjusted odds ratio 3.63; 95% confidence interval 0.92–14.29, P = 0.066) was attenuated after adjusting for retained covariates of age, race, gastroesophageal reflux disease, hiatal hernia, and proton pump inhibitor use. Within the subset of patients with cancer, prior treatment with radiation or chemotherapy was not associated with BE. There were no significant differences between cases and controls in the proportions of subjects with several specific malignancies in first‐ or second‐degree relatives. In conclusion, the risk of BE in men may be elevated with prior personal history of oropharyngeal or prostate cancer. However, prior cancer treatments and family history of cancer were not associated with increased risk of BE. Further studies are needed to elucidate if there is a causative relationship or shared risk factors between prostate cancer and BE.  相似文献   
93.
肿瘤的转移是一个多步骤复杂的过程,肝转移是结直肠癌最常见的转移方式之一,对转移机制的理解和深入研究有助于寻求解决结直肠癌肝转移的方法,当前研究认为microRNA参与了肿瘤的转移与复发,通过对结直肠癌肝转移相关microRNA的研究,为疾病的发生发展、诊断治疗及预后等方面的研究提供了新的思路。归纳了结直肠癌肝转移相关microRNA的研究进展,回顾了microRNA的生物学功能以及分子机制,表明microRNA在肿瘤转移领域具有重要的意义,尤其在结直肠癌肝转移方面发挥着重要的作用。  相似文献   
94.
IntroductionRetroperitoneal mucinous cystic neoplasms are uncommon, and little is known about the etiology of the disease. Malignant forms of these are extremely rare. Here, we report a case of primary retroperitoneal mucinous cystadenocarcinoma (PRMC), which demonstrated unexpectedly aggressive progression despite finding only a limited area of adenocarcinoma.Presentation of caseA 62-year-old woman with a complaint of abdominal discomfort was admitted to the hospital. Abdominal CT and MRI showed multiple large retroperitoneal cysts dislocating the right kidney nearly to the center of the abdomen. Transabdominal resection of the cysts was performed. Those cysts contained 1100 ml of mucinous fluids in total. Cytological examination of those fluids revealed no malignant cells. The cyst wall was lined with mucinous epithelial cells, and contained some ovarian-type stroma. Also, there was a focal area of adenocarcinoma in the cyst wall, and the lesion was diagnosed as primary retroperitoneal mucinous cystadenocarcinoma. Eight months later, the patient developed lumbar bone metastasis. Chemotherapy with S-1, an oral fluoropyrimidine, and docetaxel had been begun immediately; however, the disease had rapidly spread in the retroperitoneum. Eventually, the patient died of the disease 15 months after surgery.DiscussionRetroperitoneal mucinous cystic neoplasms are considered to be metaplasia of embryonal coelomic epithelium. Complete excision without rupture is essential. However, variance of biological aggressiveness might exist in PRMCs.ConclusionRetroperitoneal mucinous cystadenocarcinoma is a rare tumor, and it is urgently necessary to elucidate the etiology of an effective therapy for the disease.  相似文献   
95.
96.
目的评价阳性淋巴结对数比(LODDS)在预测不同胸段食管鳞癌患者长期预后中的作用。方法回顾性分析731例食管鳞癌根治术后患者临床资料,分析LODDS在全组患者、术后淋巴结阴性患者和术中清扫淋巴结数目<12枚患者中预测预后的价值。结果LODDS与阳性淋巴结个数和术中淋巴结清扫数目均显著相关(r=0.696、-0.530,均P=0.000)。ROC曲线分析结果显示LODDS最佳截点值为-1.028。多因素分析结果显示患者性别、年龄、食管病变部位、pT分期、阳性淋巴结个数和LODDS值为全组患者生存和术中淋巴结清扫数目≥12枚患者OS的独立影响因素(P<0.05);患者性别、年龄、食管病变部位、pT分期和LODDS值为术后淋巴结阴性患者生存的独立影响因素(P<0.05),而pT分期和LODDS值为术中淋巴结清扫数目<12枚患者OS的独立影响因素(P<0.05)。结论LODDS可以作为不同胸段食管鳞癌根治术后患者的独立性预后指标。  相似文献   
97.
98.
Background:Gastrointestinal complications and malnutrition are common problems that affect postoperative rehabilitation and survival of patients with esophageal cancer. Evidence has shown that probiotics have a positive effect on improving gastrointestinal complications and nutritional status of patients with esophageal cancer after surgery, but there is a lack of prospective studies on this topic. We designed this prospective randomized controlled trial to evaluate the effects of probiotics on gastrointestinal complications and nutritional status in patients with postoperative esophageal cancer.Methods:This is a prospective, randomized, double-blind, placebo-controlled trial. It was approved by the Clinical Research Ethics Committee of our hospital. 192 patients will be randomly divided into probiotics group and the placebo group in a 1:1 ratio. After operation, probiotics and placebo will be given orally for 8 weeks. The indexes of nutritional status and incidence of digestive tract complications will be recorded and the data will be analyzed by SPSS 18.0 software.Discussion:This study will evaluate the effect of probiotics on gastrointestinal complications and nutritional status of postoperative patients with esophageal cancer. The results of this study will provide clinical basis for the use of probiotics in postoperative treatment of esophageal cancer.Trial registration:OSF Registration number: D DOI 10.17605/OSF.IO/QHW86  相似文献   
99.
100.
        2020年初美国临床肿瘤学会(American Society of Clinical Oncology,ASCO)首次在Journal of Clinical Oncology发布了《卵巢上皮性癌胚系和体细胞肿瘤检测指南》[1]。该指南以2007—2019年间发表的6篇Meta分析、11篇随机对照试验、2篇观察性研究的相关文献为主要参考依据,为卵巢上皮性癌肿瘤基因突变检测相关临床应用和实施提供了指导和建议。该指南的框架架构由背景、方法、结果、推荐、医患沟通、健康差异、成本影响等十几个板块组成,主要阐述了3个主要问题:应在哪些个体中进行胚系和体细胞突变肿瘤风险评估、咨询和基因检测,哪些胚系基因突变已经被证明对卵巢癌临床治疗有指导价值,以及最合适的卵巢癌基因突变检测时机。本文对该指南进行剖析和解读,以期为卵巢癌基因检测的临床应用提供相关依据和指导,为卵巢癌的规范诊治提供借鉴,也为国内同道制定相关指南提供参考。 浏览更多请关注本刊微信公众号及当期杂志。  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