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   4972篇
  免费   303篇
  国内免费   27篇
耳鼻咽喉   87篇
儿科学   87篇
妇产科学   36篇
基础医学   606篇
口腔科学   252篇
临床医学   353篇
内科学   1339篇
皮肤病学   114篇
神经病学   316篇
特种医学   125篇
外科学   985篇
综合类   14篇
预防医学   117篇
眼科学   100篇
药学   272篇
中国医学   7篇
肿瘤学   492篇
  2023年   68篇
  2022年   114篇
  2021年   191篇
  2020年   98篇
  2019年   133篇
  2018年   151篇
  2017年   127篇
  2016年   138篇
  2015年   138篇
  2014年   163篇
  2013年   181篇
  2012年   333篇
  2011年   330篇
  2010年   158篇
  2009年   139篇
  2008年   231篇
  2007年   251篇
  2006年   233篇
  2005年   218篇
  2004年   229篇
  2003年   204篇
  2002年   159篇
  2001年   93篇
  2000年   101篇
  1999年   94篇
  1998年   47篇
  1997年   49篇
  1996年   31篇
  1995年   30篇
  1994年   17篇
  1993年   22篇
  1992年   59篇
  1991年   56篇
  1990年   49篇
  1989年   65篇
  1988年   62篇
  1987年   52篇
  1986年   72篇
  1985年   56篇
  1984年   53篇
  1983年   36篇
  1982年   20篇
  1981年   18篇
  1979年   30篇
  1978年   15篇
  1977年   16篇
  1972年   21篇
  1970年   18篇
  1969年   21篇
  1968年   18篇
排序方式: 共有5302条查询结果,搜索用时 15 毫秒
101.
New RNA replicases were isolated and purified from Escherichia coli Q13 infected with SP or FI phages showing different serological properties. These replicases showed a template specificity different from that of Qbeta replicase.  相似文献   
102.
To investigate the association of westernized food habits and concentrations of serum lipids in the Japanese, we studied 1200 healthy Japanese living in Hiroshima prefecture and 1483 ethnic Japanese from Hiroshima prefecture living in the Hawaii Islands and Los Angeles. The nutritional assessments were made by the same dietitians. No major difference was observed in the total energy intake between the Japanese and the Japanese-Americans in both males and females. However, the intake of animal fat and simple carbohydrates (especially fructose) were markedly greater, and that of complex carbohydrates lower, in the Japanese-Americans compared with the Japanese. The mean serum cholesterol (CH), LDL-CH and serum triglyceride (TG) levels were significantly higher in the Japanese-Americans in both sexes. The mean HDL-CH concentration was similar between the two groups in males, but it was approximately 7 mg/dl higher in Japanese-American females. Using the 75 percentile values of CH and TG in the Japanese in Hiroshima, the frequency of WHO types IIa and IIb hyperlipidemia was about twice as high in the Japanese-Americans. These results suggest that westernized food habits in the Japanese include qualitative changes in animal fat, simple carbohydrate and complex carbohydrate diet rather than an increase in the total energy intake. These changes are associated with marked increases in the concentrations of serum CH and TG and increased prevalence of types IIa and IIb hyperlipidemia.  相似文献   
103.
Summary A case of pancreatic arteriovenous malformation (AVM) with hepatocellular carcinoma is reported. The patient, a 56-year-old Japanese man, was asymptomatic. The pancreatic lesion was found incidentally during an evaluation for hepatocellular carcinoma. Celiac arteriogram demonstrated tortuous feeding arteries, a racemose intrapancreatic stain, which disappeared before the venous phase, and early portal filling.  相似文献   
104.
We describe an XXX female patient accompanied with essential thrombocythemia. To our knowledge this is the first case ever to have been reported. The patient was asymptomatic, but her platelet count had increased to 111.2 x 10(4)/microliter, and she was diagnosed as having essential thrombocythemia based on the diagnostic criteria of the Polycythemia Vera Study Group. At the same time, chromosome analysis of bone marrow cells revealed that she was an XXX female. The patient remained asymptomatic throughout the course of treatment.  相似文献   
105.
106.
107.
Vascular access intervention therapy (VAIVT) is necessary to maintain vascular access in patients undergoing hemodialysis. VAIVT‐associated vasodilatation is painful. However, few reports have focused on effective pain relief at the time of VAIVT. The present study was performed to determine whether lidocaine‐propitocain cream, a eutectic mixture of local anesthetics (EMLA), effectively reduces VAIVT‐associated pain in patients undergoing hemodialysis. This placebo‐controlled, double‐blind, crossover study was conducted in a single center. Among 210 patients who underwent a total of 437 VAIVT procedures from August 2017 to June 2018, 30 patients were randomly allocated to either the EMLA–placebo arm or placebo–EMLA arm at the time of VAIVT. EMLA application significantly reduced the visual analog scale score compared with placebo (47.0 ± 21.1 vs. 68.6 ± 20.7 mm, respectively; P < 0.05). EMLA is a safe and effective treatment for relief of VAIVT‐associated pain in patients undergoing hemodialysis.  相似文献   
108.
109.
Three species of the Kudoid parasite (Myxozoa: Multivalvulida) were observed in the somatic muscle of Japanese parrotfish Calotomus japonicus caught off the coast of western Japan. All three species formed pseudocysts in myofibers and caused subclinical infections. The three Kudoa species were distinguished by spore morphology, as well as their 18S and 28S rDNA sequences. We identified a previously undescribed taxa Kudoa igami n. sp. with spores that were stellate with rounded peripheral edges and five to six polar capsules (prevalence 29.3 %). Kudoa igami n. sp. were morphologically most similar to Kudoa neothunni but were distinguishable by a more rounded shape in the apical view. Molecular analyses demonstrated that the K. igami n. sp. is closely related to Kudoa thalassomi; however, the similarity in the 28S rDNA sequence was <96 % and the spore morphology was different. We found Kudoa thalassomi in one sample (prevalence 2.4 %), which is a new host and geographical record for this species. Kudoa lateolabracis, which causes postmortem myoliquefaction in Chinese sea bass Lateolabrax sp. and olive flounder Paralichthys olivaceus was found in Japanese parrotfish (prevalence 41.5 %) for the first time, but did not cause myoliquefaction. We also expanded the host record for the brain-infecting Kudoa yasunagai (prevalence 94.1 %). In addition, an unidentified microsporidia was observed in the somatic muscle (prevalence 23.3 %).  相似文献   
110.
Alkaline conditions in the oral cavity may be caused by a variety of stimuli, including tobacco products, antacids, alkaline drinking water and bicarbonate toothpaste. However, the effects of an alkaline pH on the oral mucosa had not been elucidated. The purpose of this study was to investigate how basal keratinocytes are actively involved in re-epithelialization after alkaline chemical injury. We generated epithelial defects in the oral mucosa of mice by applying an alkaline chemical, and the localization of cytokeratin 13, cytokeratin 14, PCNA and p63 was investigated during the re-epithelialization process. PCNA- and p63-positive staining was seen in basal cells covering the wound surface at 1 day after the chemical injury. Cytokeratin 14-positive and PCNA-negative basal keratinocytes were localized in a few layers of the wound epithelium during epithelial outgrowth. Cytokeratin 14-positive and PCNA-positive basal keratinocytes, indicating proliferation, were localized over the entire layer of the epithelium at the wound margin. These results imply that basal keratinocytes at the wound margin migrate to the wound surface, provoke differentiation and keratinization during epithelial outgrowth and that epithelial cells are supplied from the wound margin to the epithelial outgrowth after alkaline chemical injury.  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