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   4667篇
  免费   354篇
  国内免费   288篇
耳鼻咽喉   5篇
儿科学   154篇
妇产科学   34篇
基础医学   314篇
口腔科学   8篇
临床医学   564篇
内科学   933篇
皮肤病学   16篇
神经病学   12篇
特种医学   357篇
外国民族医学   1篇
外科学   1496篇
综合类   584篇
预防医学   135篇
眼科学   14篇
药学   389篇
中国医学   131篇
肿瘤学   162篇
  2024年   10篇
  2023年   52篇
  2022年   87篇
  2021年   117篇
  2020年   114篇
  2019年   93篇
  2018年   75篇
  2017年   93篇
  2016年   115篇
  2015年   139篇
  2014年   274篇
  2013年   328篇
  2012年   248篇
  2011年   251篇
  2010年   242篇
  2009年   263篇
  2008年   294篇
  2007年   272篇
  2006年   281篇
  2005年   244篇
  2004年   177篇
  2003年   161篇
  2002年   150篇
  2001年   145篇
  2000年   120篇
  1999年   88篇
  1998年   77篇
  1997年   93篇
  1996年   56篇
  1995年   58篇
  1994年   66篇
  1993年   41篇
  1992年   39篇
  1991年   29篇
  1990年   49篇
  1989年   27篇
  1988年   33篇
  1987年   37篇
  1986年   36篇
  1985年   18篇
  1984年   27篇
  1983年   13篇
  1982年   29篇
  1981年   17篇
  1980年   22篇
  1979年   25篇
  1978年   17篇
  1976年   14篇
  1975年   10篇
  1974年   16篇
排序方式: 共有5309条查询结果,搜索用时 15 毫秒
1.
2.
BackgroundBile reflux is a factor in the appearance of severe esophagitis and Barrett’s esophagus, which have been reported after sleeve gastrectomy (SG). Incompetent lower esophageal sphincter and increased gastroesophageal acid reflux have been demonstrated after this operation. Some reports have shown bile content in the antrum during endoscopic control, but no investigations objectively confirm the presence of duodenogastric bile reflux in these patients.ObjectivesTo evaluate the presence of duodenogastric bile reflux (DGR) after SG in patients presenting reflux symptoms.SettingUniversity hospital.MethodsProspective study of 22 patients presenting reflux symptoms who underwent SG for morbid obesity and who received endoscopic evaluation and scintigraphic study to confirm esophagitis and duodenogastric bile reflux.ResultsErosive esophagitis was observed in 11 patients and Barrett’s esophagus in 2 patients. Seven patients (31.8%) presented positive DGR. Among them, 3 had type B and C esophagitis. The other 4 patients did not present esophagitis in spite of reflux symptoms.ConclusionDGR may be present in patients with gastroesophageal reflux after SG. This line of investigation requires further studies to confirm this hypothesis.  相似文献   
3.
4.
5.
目的 挖掘藏医治疗肝胆疾病的用药规律,寻找核心药组,并预测核心药组的潜在靶点,以探讨核心药组治疗肝胆疾病的作用机制。方法 收集藏医药典籍中治疗肝胆疾病处方,采用SPSS软件进行Apriori算法关联规则分析得到藏医治疗肝胆疾病的核心药组。检索中药系统药理学分析平台(TCMSP)、Therapeutic Target Database (TTD)、Genecards、Metascape等数据库进行基因本体(GO)和KEGG富集分析。结果 共纳入607首方剂,数据挖掘得到藏医治疗肝胆疾病的核心药组为蒂达-洪连-波棱瓜子。收集到核心药组56个活性成分,作用于47个关键靶点,预测出1194条生物过程、49个细胞组成、54个分子功能以及226条信号通路。结论 藏医在治疗肝胆疾病中主要以“清赤巴热”为核心,所使用方剂中的药物多以苦味为主;核心药组治疗肝胆疾病可能是通过缓解体内氧化应激、降低炎症表达以及调节胆汁酸肝肠循环等作用机制。  相似文献   
6.
7.
BACKGROUNDHepatobiliary diseases result in the accumulation of toxic bile acids (BA) in the liver, blood, and other tissues which may contribute to an unfavorable prognosis.AIMTo discover and validate diagnostic biomarkers of cholestatic liver diseases based on the urinary BA profile.METHODSWe analyzed urine samples by liquid chromatography-tandem mass spectrometry and compared the urinary BA profile between 300 patients with hepatobiliary diseases vs 103 healthy controls by statistical analysis. The BA profile was characterized using BA indices, which quantifies the composition, metabolism, hydrophilicity, and toxicity of the BA profile. BA indices have much lower inter- and intra-individual variability compared to absolute concentrations of BA. In addition, BA indices demonstrate high area under the receiver operating characteristic curves, and changes of BA indices are associated with the risk of having a liver disease, which demonstrates their use as diagnostic biomarkers for cholestatic liver diseases.RESULTSTotal and individual BA concentrations were higher in all patients. The percentage of secondary BA (lithocholic acid and deoxycholic acid) was significantly lower, while the percentage of primary BA (chenodeoxycholic acid, cholic acid, and hyocholic acid) was markedly higher in patients compared to controls. In addition, the percentage of taurine-amidation was higher in patients than controls. The increase in the non-12α-OH BA was more profound than 12α-OH BA (cholic acid and deoxycholic acid) causing a decrease in the 12α-OH/ non-12α-OH ratio in patients. This trend was stronger in patients with more advanced liver diseases as reflected by the model for end-stage liver disease score and the presence of hepatic decompensation. The percentage of sulfation was also higher in patients with more severe forms of liver diseases.CONCLUSIONBA indices have much lower inter- and intra-individual variability compared to absolute BA concentrations and changes of BA indices are associated with the risk of developing liver diseases.  相似文献   
8.
Differentiation of Streptococcus pneumoniae from other Streptococcus mitis group streptococci (SMGS) remains challenging despite the introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). While the bile solubility test (BST) provides most reliable discrimination of pneumococci, its practical implementation is limited by subjective visual interpretation and frequent inconclusive results. We aimed to develop a rapid confirmation BST based on direct-on-target MALDI-TOF MS assay. After establishment of optimal test conditions, test performance was evaluated on 36 consecutive clinical SMGS isolates. Colony material was suspended and pipetted onto a MALDI target. After drying, sodium deoxycholate in different concentrations (2%, 5%, and 10 %) was added. Incubation for 30 min (at room temperature or 35 °C) was followed by liquid removal and spot washing. After adding 70 % formic acid, spots were overlaid with matrix and measured (MALDI Biotyper smart, Bruker). The absence of microbial spectra (Biotyper score <1.7) in samples with sodium deoxycholate indicated efficient removal of bacterial biomass due to bile solubility, thus, identifying pneumococci. In contrast, scores ≥1.7 were interpreted as lack of bile solubility and confirmation as viridans streptococci other than S. pneumoniae. Highest test accuracy was achieved applying 5% sodium deoxycholate at 35 °C and 10 % sodium deoxycholate at room temperature. These test conditions provided 100 % sensitivity and 100 % specificity for discrimination of S. pneumoniae. The developed MALDI-TOF MS-based BST is an easy-to-perform assay with minimum hands-on time and objective readout. The promising results of this proof-of-principle study warrant confirmation with large collections of epidemiologically diverse strains.  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