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   69245篇
  免费   4492篇
  国内免费   1790篇
耳鼻咽喉   621篇
儿科学   1322篇
妇产科学   851篇
基础医学   5402篇
口腔科学   1409篇
临床医学   7783篇
内科学   7051篇
皮肤病学   672篇
神经病学   5253篇
特种医学   1593篇
外国民族医学   6篇
外科学   6514篇
综合类   12190篇
现状与发展   1篇
一般理论   7篇
预防医学   7203篇
眼科学   1040篇
药学   5822篇
  124篇
中国医学   8762篇
肿瘤学   1901篇
  2024年   164篇
  2023年   1249篇
  2022年   2116篇
  2021年   3148篇
  2020年   2885篇
  2019年   2980篇
  2018年   2679篇
  2017年   2424篇
  2016年   2198篇
  2015年   1922篇
  2014年   4609篇
  2013年   4376篇
  2012年   3997篇
  2011年   4911篇
  2010年   4257篇
  2009年   3329篇
  2008年   3092篇
  2007年   3190篇
  2006年   2835篇
  2005年   2369篇
  2004年   1926篇
  2003年   1797篇
  2002年   1254篇
  2001年   1136篇
  2000年   911篇
  1999年   828篇
  1998年   643篇
  1997年   587篇
  1996年   497篇
  1995年   532篇
  1994年   504篇
  1993年   393篇
  1992年   378篇
  1991年   329篇
  1990年   288篇
  1989年   273篇
  1988年   284篇
  1987年   234篇
  1986年   221篇
  1985年   447篇
  1984年   430篇
  1983年   337篇
  1982年   367篇
  1981年   360篇
  1980年   350篇
  1979年   320篇
  1978年   281篇
  1977年   249篇
  1976年   192篇
  1975年   123篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
Oocyte and embryo grading is one of the most important steps in assisted reproductive technology to identify the best among cultured embryos for transfer or vitrification. The most commonly used non-invasive method is morphological assessment of gametes and embryos using a microscope. This method despite being simple and cost-effective has interobserver and intraobserver variability and subjectivity and has little to offer about the physiological state of embryos. This review sourced research articles and reviews pertaining to other non-invasive assessment methodologies from Medline and PubMed to collate latest technologies in vogue and identify novel methodologies of the future. The review assesses the current understanding in oocyte and embryo grading and touches upon novel non-invasive techniques and potential biomarkers to identify the best embryo. The latest available literature on time-lapse imaging, hierarchical algorithms, omics (consisting of proteomics and secretomes), miRNAs, mitochondrial RNAs and artificial intelligence has been accessed to summarize the enormous information available, to identify gaps in current interpretations, to identify emerging technologies and to provide direction for future research. This review will greatly benefit anyone practicing assisted reproduction and clinical embryology.  相似文献   
2.
3.
4.
5.
PurposeThe purpose of this study was to make a systematic review and meta-analysis to determine the stent diameter (8 mm vs. 10 mm) that conveys better safety and clinical efficacy for transjugular intrahepatic portosystemic shunt (TIPS).Materials and methodsFour databases were used to identify clinical trials published from inception until March 2020. Data were extracted to estimate and compare one-year and three-year overall survivals, hepatic encephalopathy, variceal rebleeding, and shunt dysfunction rates between patients with 8 mm covered stents and those with 10 mm covered stents.ResultsFive eligible studies were selected, which included 489 patients (316 men, 173 women). The 8 mm covered stent group had higher efficacy regarding one-year or three-year overall survival (odds ratio [OR], 2.88; P = 0.003) and (OR, 1.81; P = 0.04) and lower hepatic encephalopathy (OR, 0.69; P = 0.04) compared with 10 mm covered stent group. There were no significant differences in variceal rebleeding rate (OR 0.80; P = 0.67). However, shunt dysfunction was lower in 10 mm covered stent group (OR, 2.26; P = 0.003).ConclusionsOur results suggest that the use of 8 mm covered stents should be preferred to that of 10 mm covered stents for TIPS placement when portal pressure is frequently monitored.  相似文献   
6.
7.
PurposeTo review and to compare indirectly the outcomes of minimally invasive therapies for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia.Materials and MethodsA literature search via Medline and Cochrane Central databases was completed for randomized control studies published between January 2000 to April 2020 for the following therapies: Rezum, Urolift, Aquablation, and prostatic artery embolization (PAE). Data on the following variables were included: International prostate symptom score (IPSS), maximum urinary flow rate, quality of life, and postvoid residual (PVR). Standard mean differences between treatments were compared through a meta-analysis using transurethral resection of the prostate (TURP) to assess differences in treatment effect.ResultsThere was no significant difference in outcomes between therapies for IPSS at the 3, 6, and 12-month follow ups. Although outcomes for Rezum were only available out to 3 months, there were no consistently significant differences in outcomes when comparing Aquablation versus PAE versus Rezum. TURP PVR was significantly better than Urolift at 3, 6, and 12 months. No significant differences in minor or major adverse events were noted.ConclusionAlthough significant differences in outcomes were limited, Aquablation and PAE were the most durable at 12 months. PAE has been well studied on multiple randomized control trials with minimal adverse events while Aquablation has limited high quality data and has been associated with bleeding-related complications.  相似文献   
8.
Background/PurposeA small number of Hirschsprung disease (HD) patients develop inflammatory bowel disease (IBD)-like symptoms after pullthrough surgery. The etiology and pathophysiology of Hirschsprung-associated IBD (HD-IBD) remains unknown. This study aims to further characterize HD-IBD, to identify potential risk factors and to evaluate response to treatment in a large group of patients.MethodsRetrospective study of patients diagnosed with IBD after pullthrough surgery between 2000 and 2021 at 17 institutions. Data regarding clinical presentation and course of HD and IBD were reviewed. Effectiveness of medical therapy for IBD was recorded using a Likert scale.ResultsThere were 55 patients (78% male). 50% (n = 28) had long segment disease. Hirschsprung-associated enterocolitis (HAEC) was reported in 68% (n = 36). Ten patients (18%) had Trisomy 21. IBD was diagnosed after age 5 in 63% (n = 34). IBD presentation consisted of colonic or small bowel inflammation resembling IBD in 69% (n = 38), unexplained or persistent fistula in 18% (n = 10) and unexplained HAEC >5 years old or unresponsive to standard treatment in 13% (n = 7). Biological agents were the most effective (80%) medications. A third of patients required a surgical procedure for IBD.ConclusionMore than half of the patients were diagnosed with HD-IBD after 5 years old. Long segment disease, HAEC after pull through operation and trisomy 21 may represent risk factors for this condition. Investigation for possible IBD should be considered in children with unexplained fistulae, HAEC beyond the age of 5 or unresponsive to standard therapy, and symptoms suggestive of IBD. Biological agents were the most effective medical treatment.Level of EvidenceLevel 4  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