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   192098篇
  免费   13664篇
  国内免费   5129篇
耳鼻咽喉   2542篇
儿科学   3106篇
妇产科学   2516篇
基础医学   26117篇
口腔科学   4413篇
临床医学   20633篇
内科学   30868篇
皮肤病学   5062篇
神经病学   12574篇
特种医学   9635篇
外国民族医学   22篇
外科学   22158篇
综合类   14204篇
现状与发展   19篇
一般理论   29篇
预防医学   13148篇
眼科学   4568篇
药学   19074篇
  80篇
中国医学   6135篇
肿瘤学   13988篇
  2024年   315篇
  2023年   1824篇
  2022年   4979篇
  2021年   7466篇
  2020年   4599篇
  2019年   4818篇
  2018年   5547篇
  2017年   5080篇
  2016年   5706篇
  2015年   8429篇
  2014年   10296篇
  2013年   11608篇
  2012年   17189篇
  2011年   16931篇
  2010年   10905篇
  2009年   9283篇
  2008年   11979篇
  2007年   11346篇
  2006年   10481篇
  2005年   9406篇
  2004年   7562篇
  2003年   6626篇
  2002年   5643篇
  2001年   4166篇
  2000年   3677篇
  1999年   2778篇
  1998年   1257篇
  1997年   1067篇
  1996年   775篇
  1995年   705篇
  1994年   608篇
  1993年   462篇
  1992年   884篇
  1991年   826篇
  1990年   734篇
  1989年   623篇
  1988年   522篇
  1987年   507篇
  1986年   363篇
  1985年   386篇
  1984年   283篇
  1983年   203篇
  1982年   140篇
  1981年   179篇
  1980年   136篇
  1979年   230篇
  1978年   167篇
  1976年   136篇
  1975年   124篇
  1974年   147篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
2.
Direct peroral cholangioscopy (POC) using an ultra‐slim upper endoscope is one modality of POC for intraductal endoscopic evaluation and treatment of the bile duct. Choledochoduodenostomy (CDS) is one modality of biliary bypass surgery that provides a new route to the bile duct. We carried out direct POC using an ultra‐slim upper endoscope without the use of accessories in 10 patients (four sump syndromes, three bile duct strictures and three intrahepatic duct stones) previously undergoing surgical CDS. Direct POC was successful in all patients. The use of an intraductal balloon catheter was required in one patient for advancement of the endoscope into the bile duct. Distal bile ducts with sump syndromes were cleared using baskets and water irrigation under direct POC. Cholangiocarcinoma was diagnosed in one patient with hilar bile duct stricture after cholangioscopic evaluation and a targeting forceps biopsy under direct POC. Intrahepatic duct stones were successfully extracted after intraductal fragmentation under direct POC. Oozing bleeding occurred during intraductal lithotripsy but stopped spontaneously. Direct POC using an ultra‐slim upper endoscope without the assistance of accessories can easily be carried out in patients undergoing CDS.  相似文献   
3.
4.
5.
Synovial chondromatosis is a rare lesion in the wrist, but some cases in the distal radioulnar joint have been reported and previous case reports emphasize joint calcifications, shown on preoperative plain radiographs. We report an extremely uncommon case of synovial chondromatosis in the pisotriquetral joint, in which radiographs and magnetic resonance imaging did not demonstrate apparent calcified bodies. In our case, for the accurate diagnosis and treatment, surgical exploration of the joint and synovectomy with removal of loose bodies was performed.  相似文献   
6.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
7.
8.
9.
背景 在人口老龄化日益加剧的社会背景之下,家庭养老功能不断减弱,机构养老成为今后发展的必然趋势。据报道,很多养老机构的老年人营养不合理,严重影响老年人的健康状况与生活质量。目的 通过调查北京市养老机构老年人营养现状及其影响因素,为全科医师营养教育及老年人生活质量提升提供理论依据。方法 2014年10月-2015年12月,采用方便整群抽样的方法,抽取了北京市7家养老机构,对符合纳入标准的老年人进行面对面问卷调查,问卷内容包括:一般情况、微型营养评定量表(MNA)、日常生活活动能力指数(BI)、老年人抑郁量表(GDS)。采用二元Logistic回归分析养老机构老年人营养状况的影响因素。结果 本研究共发放问卷258份,回收有效问卷258份,有效回收率为100%。被调查的258例老年人中,存在营养不良及存在营养不良发生风险的老年人共计75例(29.1%)。不同年龄、性别、婚姻状况、体质指数(BMI)、医疗费用支付方式、生活自理能力及精神状态的老年人营养状况比较,差异有统计学意义(P<0.05)。二元Logistic回归分析结果显示:年龄〔OR(95%CI)=2.349(1.070,5.156)〕、BMI〔OR(95%CI)=0.092(0.036,0.239)〕、医疗费用支付方式〔OR(95%CI)=0.208(0.083,0.522)〕、日常活动能力〔OR(95%CI)=10.214(3.099,33.669)〕、患病种数〔OR(95%CI)=2.682(1.248,5.763)〕及精神状态〔OR(95%CI)=4.822(2.005,11.600)〕是老年人营养状况的影响因素(P<0.05)。结论 北京地区养老机构的老年人面临着营养不良及营养不良发生风险的健康威胁,高龄、低BMI、抑郁、合并多种疾病、日常活动能力低下及无医保是其独立危险因素,需要对老年人加强个性化营养教育和营养治疗。  相似文献   
10.
Lessons Learned
  • The combination of trametinib and sorafenib has an acceptable safety profile, albeit at doses lower than approved for monotherapy.
  • Maximum tolerated dose is trametinib 1.5 mg daily and sorafenib 200 mg twice daily.
  • The limited anticancer activity observed in this unselected patient population does not support further exploration of trametinib plus sorafenib in patients with hepatocellular carcinoma.
BackgroundThe RAS/RAF/MEK/ERK signaling pathway is associated with proliferation and progression of hepatocellular carcinoma (HCC). Preclinical data suggest that paradoxical activation of the MAPK pathway may be one of the resistance mechanisms of sorafenib; therefore, we evaluated trametinib plus sorafenib in HCC.MethodsThis was a phase I study with a 3+3 design in patients with treatment‐naïve advanced HCC. The primary objective was safety and tolerability. The secondary objective was clinical efficacy.ResultsA total of 17 patients were treated with three different doses of trametinib and sorafenib. Two patients experienced dose‐limiting toxicity, including grade 4 hypertension and grade 3 elevation of aspartate aminotransferase (AST)/alanine aminotransferase (ALT)/bilirubin over 7 days. Maximum tolerated dose was trametinib 1.5 mg daily and sorafenib 200 mg twice a day. The most common grade 3/4 treatment‐related adverse events were elevated AST (37%) and hypertension (24%). Among 11 evaluable patients, 7 (63.6%) had stable disease with no objective response. The median progression‐free survival (PFS) and overall survival (OS) were 3.7 and 7.8 months, respectively. Phosphorylated‐ERK was evaluated as a pharmacodynamic marker, and sorafenib plus trametinib inhibited phosphorylated‐ERK up to 98.1% (median: 81.2%) in peripheral blood mononuclear cells.ConclusionTrametinib and sorafenib can be safely administered up to trametinib 1.5 mg daily and sorafenib 200 mg twice a day with limited anticancer activity in advanced HCC.  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