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   2570篇
  免费   84篇
  国内免费   14篇
耳鼻咽喉   23篇
儿科学   51篇
妇产科学   32篇
基础医学   348篇
口腔科学   198篇
临床医学   187篇
内科学   524篇
皮肤病学   47篇
神经病学   137篇
特种医学   185篇
外国民族医学   1篇
外科学   388篇
综合类   52篇
一般理论   2篇
预防医学   150篇
眼科学   60篇
药学   109篇
中国医学   7篇
肿瘤学   167篇
  2023年   19篇
  2022年   20篇
  2021年   33篇
  2020年   33篇
  2019年   28篇
  2018年   30篇
  2017年   36篇
  2016年   35篇
  2015年   55篇
  2014年   44篇
  2013年   67篇
  2012年   88篇
  2011年   100篇
  2010年   71篇
  2009年   76篇
  2008年   96篇
  2007年   106篇
  2006年   110篇
  2005年   103篇
  2004年   117篇
  2003年   93篇
  2002年   83篇
  2001年   67篇
  2000年   83篇
  1999年   93篇
  1998年   75篇
  1997年   57篇
  1996年   59篇
  1995年   52篇
  1994年   41篇
  1993年   38篇
  1992年   41篇
  1991年   48篇
  1990年   39篇
  1989年   51篇
  1988年   54篇
  1987年   59篇
  1986年   47篇
  1985年   35篇
  1984年   29篇
  1983年   24篇
  1982年   26篇
  1981年   13篇
  1980年   15篇
  1979年   15篇
  1977年   14篇
  1973年   15篇
  1972年   14篇
  1971年   14篇
  1969年   15篇
排序方式: 共有2668条查询结果,搜索用时 15 毫秒
81.
82.
BACKGROUND: Surgery for advanced esophageal carcinoma has its limits as regards aggressiveness and therapeutic effect, therefore effective multimodality treatment is required to obtain better survival. The objective of this study was to evaluate whether daily continuous infusion of CDDP could achieve a higher clinical response rate with less toxicity than its drip infusion in the previous phase II study that we had conducted. METHODS: Patients with primary extensive or relapsed esophageal carcinoma after esophagectomy, which had distant organ metastasis and histologically proven SCC, were eligible for this study. A dose of 20 mg/m(2) of cisplatin and 800 mg/m(2) of 5-fluorouracil was given by continuous infusion for 24 h on days 1-5. This treatment was repeated every 4 weeks for up to four cycles. A total of 36 men and six women with a median age of 64 (range 39-75) years were registered and 36 patients were eligible. RESULTS: The overall response rate of the registered patients was 33.3% (12/36) and the median response duration was 175 days. Median survival time was 201.5 days and the 1-year survival rate was 27.8%. Change from bolus to continuous infusion of cisplatin affected neither the type nor the degree of toxicity. CONCLUSION: Daily continuous infusion of cisplatin was not associated with higher response or lower toxicity than those seen with the high-dose bolus or multibolus treatment regimens. We conclude that this regimen in this setting is not worthy of further phase III trials. JEOG is now evaluating other drug combination regimens.  相似文献   
83.
84.
Urinary metabolic fingerprinting with Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) was performed to monitor metabolic changes in an alpha-naphthylisothiocyanate (ANIT)-induced rat model of intrahepatic cholestasis and to investigate the relationships among metabolic changes, histopathology, and blood chemistry. ANIT was administered orally as a single dose of 100 mg/kg. Urine samples were collected predose (-31 to -24 hours) and postdose at 0-7, 7-24, 24-31, 31-48, 48-55, 55-72, and 72-96 hours, and serum samples were collected on days 1, 2, and 4 postdose. Increased levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and total bilirubin were seen on day 2. The negative ion profiles for urine samples collected after 7-24, 24-31, 31-48, and 48-55 hours differed from the predose profile based on principal component analysis. Onset of recovery was observed after 24-31 hours, when the urinary composition reverted toward the predose position. In conclusion, it is possible to monitor the progression of and recovery from drug-induced hepatotoxicity by urinary metabolic fingerprinting with FT-ICR MS and to search for potential biomarkers involved in intrahepatic cholestasis.  相似文献   
85.
86.
87.
The objective of this study was to three-dimensionally observe the morphological characteristics of mesiobuccal root canals of Japanese maxillary first molars using microcomputed tomography (Micro-CT) and classify root canal variations. This study used 90 maxillary first molars. Three-dimensional reconstruction was performed using data obtained by Micro-CT, and cross-sections of the root canals were observed. Moreover, the root canal morphology was classified by the configuration and root canal diameter, and was evaluated for occurrence using the classification by Weine et al. (1969) as a reference. Overall, single root canals were observed in 44.4%, incomplete separation root canals in 22.3%, and completely separate root canals (upper and lower separation root canals) in 33.3%. Mesiobuccal root canals often had intricate configurations, and accessory root canals (lateral canals and apical ramifications) were observed in most of the mesiobuccal root canals (76.7%), irrespective of whether there were ramifications of the main root canals. While there were no marked differences in the incidence of root canal ramifications between this study and earlier reports, the incidence of accessory root canals was higher in this study. This result may be explained by the far more superior visualization ability of Micro-CT than conventional methods, which allowed the detection of microscopic apical ramifications previously difficult to observe.  相似文献   
88.
89.
90.
In this study, we performed urinary metabolic fingerprinting using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) in the thioacetamide (TAA)-induced rat model of acute hepatic injury to search for useful biomarkers involved in the acute hepatic toxicity. TAA was intraperitonealy administered a single dose of 300 mg/kg, and urine sample and livers were collected on predose, and days 1, 3, 5, and 7 postdose (Days 1, 3, 5, and 7). Histopathologically, infiltration of macrophages occurred in the TAA-induced centrilobular injured area on Days 1 and 3, and the injured liver recovered on Days 5 and 7. On the scores plot of principal component analysis (PCA), the ion profiles of Days 1 and 3 were different from those of the predose, Days 5 and 7. The loading plot revealed that the metabolites causing PCA results were m/z 266.05390, 401.20737, and 429.23882. The ion at m/z 266.05390 was identified as a potassium ion adduct of deoxycytidine (dCyt). Because the appearance of urinary dCyt was corresponding to macrophage infiltration in the rat-injured liver, it was considered that the urinary dCyt might be released from infiltrated macrophages. dCty might be a biomarker for the acute hepatotoxicity in rats.  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