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   7887篇
  免费   636篇
  国内免费   493篇
耳鼻咽喉   488篇
儿科学   117篇
妇产科学   36篇
基础医学   273篇
口腔科学   65篇
临床医学   1118篇
内科学   2678篇
皮肤病学   14篇
神经病学   86篇
特种医学   257篇
外国民族医学   2篇
外科学   1103篇
综合类   1366篇
现状与发展   1篇
预防医学   283篇
眼科学   68篇
药学   438篇
  24篇
中国医学   188篇
肿瘤学   411篇
  2024年   8篇
  2023年   171篇
  2022年   208篇
  2021年   371篇
  2020年   374篇
  2019年   297篇
  2018年   300篇
  2017年   305篇
  2016年   342篇
  2015年   324篇
  2014年   566篇
  2013年   650篇
  2012年   518篇
  2011年   468篇
  2010年   424篇
  2009年   408篇
  2008年   415篇
  2007年   387篇
  2006年   366篇
  2005年   346篇
  2004年   297篇
  2003年   218篇
  2002年   207篇
  2001年   187篇
  2000年   130篇
  1999年   89篇
  1998年   106篇
  1997年   72篇
  1996年   58篇
  1995年   55篇
  1994年   49篇
  1993年   38篇
  1992年   45篇
  1991年   32篇
  1990年   39篇
  1989年   27篇
  1988年   29篇
  1987年   26篇
  1986年   10篇
  1985年   8篇
  1984年   6篇
  1983年   6篇
  1982年   6篇
  1981年   9篇
  1980年   3篇
  1978年   2篇
  1977年   8篇
  1976年   3篇
  1973年   1篇
  1972年   1篇
排序方式: 共有9016条查询结果,搜索用时 171 毫秒
1.
目的:探讨消化道肿瘤中同源重组修复相关基因(homologous recombination repair related gene,HRR)突变的发生情况及临床意义。方法:共92例消化道肿瘤患者,79例患者进行了血液标本HRR检测,53例患者进行了组织标本HRR检测,40例患者同时行血液和组织的HRR基因检测,收集患者基因检测结果及临床相关资料。结果:在79例患者血液标本检测中发现10例(12.6%)有临床意义HRR突变,在53例患者组织标本检测中发现9例(17.0%)有临床意义HRR突变。40例同时行血液和组织的HRR基因检测患者中常见的有临床意义HRR突变为CDK12突变4例(10.0%)、ATM突变3例(7.5%)、BRCA1突变2例(5.0%)。13例有临床意义HRR突变患者中常见共存突变为TP53突变10例(76.9%)、APC突变5例(38.5%)、PIK3CA突变4例(30.8%)。40例患者中13例患者血液和/或组织中有临床意义HRR突变,27例患者血液和组织中均无任何临床意义HRR突变且两组相比,有临床意义HRR突变组肿瘤突变负荷(tumor mutational burden,TMB)为6.17(2.24~11.52),而未携带HRR突变组TMB为0.4(0~3.75),差异有统计学意义(P<0.05)。40例患者组织检测中7例HRR有临床意义的突变,33例无HRR突变,血液检测中10例HRR有临床意义的突变,30例无HRR突变,一致性检验的Kappa值为0.333(P=0.031)。结论:携带有临床意义HRR突变的消化道肿瘤患者TMB更高,血液和组织检测HRR突变有较好的一致性。  相似文献   
2.
The aim of the present review was to clarify how we should detect and diagnose sessile serrated polyps (SSP) endoscopically. A systematic search was conducted of MEDLINE from January 2004 through March 2018. Nine findings: (i) proximal location; (ii) size >10 mm; (iii) irregular shape; (iv) indistinctive border; (v) cloud‐like surface; (vi) mucus cap; (vii) rim of debris in white‐light endoscopy; (viii) dilated vessels; and (ix) dilated crypts (pits) in image‐enhanced endoscopy were considered to be candidate discriminators of SSP from hyperplastic polyps. Prospective studies in a general setting are warranted to validate the above‐mentioned endoscopic features of SSP during real‐time colonoscopy and to determine whether these features are useful for the differential diagnosis of SSP.  相似文献   
3.
Endoscopic gastroplasty (EG) has been used in clinical practice to treat obesity. This systematic review has the objective of assessing if there is an acceptable level of scientific evidence on the safety and effectiveness of EG. A thorough search strategy was used up to October 2018, including the 2 most common techniques: endoscopic suturing and the primary obesity surgery endolumenal procedure. The quality of the studies was evaluated through the Joanna Briggs Institute Critical Appraisal tools for use in Systematic Reviews—“Checklist for Case Series”—and summarized using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. Only 1 randomized controlled trial (moderate GRADE evidence) was found, and the remaining were case reports or small case series (very low GRADE evidence). The literature has low scientific quality. All studies, with 1 exception, are small case series with short follow-up. One of the randomized controlled trials did not meet the primary endpoint for weight loss in both groups (EG × sham) after 1-year follow-up. The case series reported from 16% to 19% total weight loss, but few had more than 6 months of follow-up. Serious adverse events ranged from 2% to 10%. Based on current literature, there is not enough quality scientific evidence regarding long-term weight loss and the procedure’s safety to recommend the use of EG in current clinical practice.  相似文献   
4.
BackgroundEpidemiological studies on peptic ulcer disease (PUD) have shown a recent decrease in hospital admissions in Western countries.ObjectiveThis paper aimed to study the current status and risk factors of PUD in a Nigerian metropolis.MethodsA cross-sectional study of symptomatic patients at upper gastrointestinal (GI) endoscopy diagnosed with PUD from February 2014 to September 2019 at a referral endoscopy facility in Port Harcourt, Niger delta region of Nigeria. The variables studied included demographics, symptoms and duration, blood group, chronic non-steroidal anti-inflammatory (NSAID) use, smoking, endoscopic and histology findings. Statistical analysis was performed using SPSS version 20.ResultsA total of 434 upper GI endoscopies were performed during the study period with thirty-one diagnosis of PUD made. The mean age of gastric ulcer (GU) and duodenal ulcer (DU) cases were 54.4 ± 20.2yrs and 48.1 ± 14.5yrs respectively (p = 0.367). GU to DU ratio was 1.4:1. H. pylori infection, chronic NSAID use and blood group O were seen in 7(22.5%), 8(25.8%) and 18(72.0%) respectively. Major indication in 21(67.7%) cases was gastrointestinal bleeding.ConclusionThere is a low diagnostic rate of PUD (6.7%) with pre-pyloric antral gastric ulcers as most common type and multifactorial aetiology.  相似文献   
5.
Over the last decade, impressive technological advances have occurred in ultrasonography and small‐bowel endoscopy. Nowadays, endoscopic ultrasonography is an essential diagnostic tool and a therapeutic weapon for pancreatobiliary disorders. Capsule endoscopy and device‐assisted enteroscopy have quickly become the reference standard for the diagnosis of small‐bowel luminal diseases, thereby leading to radical changes in diagnostic and therapeutic pathways. We herein provide an up‐to‐date overview of the latest advances in endoscopic ultrasonography and small‐bowel endoscopy, focusing on the emerging paradigms and technological innovations that might improve clinical practice in the near future.  相似文献   
6.
7.
8.

Background and study aims

Acute upper gastrointestinal bleeding is one of the main causes of hospitalisation. The purpose of this study was to determine the prognostic factors in non-variceal upper gastrointestinal bleeding.

Patients and methods

Clinical outcomes, demographic and laboratory variables of the subjects were collected from the HIS software and national code with the SQL format from three hospitals in Qazvin. The data were linked to the database software designed by the author. Clinical and upper endoscopic findings of patients’ records were collected through a questionnaire form in the designed software database.

Results

In this study, 29.2% of patients with favourable outcome and 64.2% of patients with unfavourable clinical outcomes had a history of anticoagulant drug use before hospitalisation (p?<?0.001). The prevalence of chronic cardiovascular disease, chronic liver disease, chronic lung disease, diabetes and dialysis was higher in subjects with poor clinical outcomes than those with a favourable clinical outcome.53.1% of subjects with favourable clinical outcome and 90.5% of subjects with undesirable clinical outcomes received packed red blood cell transfusion (p?<?0.001). 16.1% of subjects with desirable clinical outcome and 86.3% of subjects with undesirable clinical outcomes received endoscopic haemostatic treatment which was statistically significant (p?<?0.001).

Conclusion

Undesirable clinical outcome in patients with acute non-variceal upper gastrointestinal bleeding has a significant statistical association with longer hospitalisation, chronic underlying disease, anticoagulant administration, packed red blood cell infusion, higher Forrest stage, low systolic blood pressure, higher age, low haemoglobin, low platelet count, high INR and high BUN at the onset of diagnosis.  相似文献   
9.
10.
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