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   5862篇
  免费   519篇
  国内免费   48篇
耳鼻咽喉   48篇
儿科学   196篇
妇产科学   110篇
基础医学   794篇
口腔科学   111篇
临床医学   689篇
内科学   972篇
皮肤病学   132篇
神经病学   339篇
特种医学   504篇
外科学   828篇
综合类   313篇
一般理论   3篇
预防医学   467篇
眼科学   145篇
药学   484篇
  2篇
中国医学   35篇
肿瘤学   257篇
  2022年   52篇
  2021年   86篇
  2020年   59篇
  2019年   65篇
  2018年   94篇
  2017年   74篇
  2016年   66篇
  2015年   108篇
  2014年   141篇
  2013年   197篇
  2012年   270篇
  2011年   277篇
  2010年   207篇
  2009年   206篇
  2008年   231篇
  2007年   257篇
  2006年   228篇
  2005年   195篇
  2004年   209篇
  2003年   184篇
  2002年   173篇
  2001年   166篇
  2000年   143篇
  1999年   138篇
  1998年   153篇
  1997年   114篇
  1996年   104篇
  1995年   108篇
  1994年   76篇
  1993年   80篇
  1992年   108篇
  1991年   107篇
  1990年   100篇
  1989年   103篇
  1988年   127篇
  1987年   127篇
  1986年   105篇
  1985年   85篇
  1984年   74篇
  1983年   74篇
  1982年   45篇
  1981年   41篇
  1979年   59篇
  1978年   51篇
  1977年   43篇
  1975年   36篇
  1972年   54篇
  1971年   42篇
  1955年   42篇
  1954年   35篇
排序方式: 共有6429条查询结果,搜索用时 15 毫秒
101.
口服莫沙必利治疗功能性消化不良的随机对照试验   总被引:5,自引:0,他引:5  
目的 观察新型促胃肠动力药莫沙必利 (胃 5 HT4受体促进剂 )对功能性消化不良 (FD)的随机对照试验。方法 FD患者 42例 ,随机分为试验组 (2 1例 ,服枸橼酸莫沙必利片 )和对照组 (2 1例 ,服吗叮啉片 )。采用GCP标准 ,双盲法观察 ,在实验开始前、服药第 1 4、2 8天记录症状变化及副作用发生情况。随机抽取部分患者于实验开始前和结束时做99MTc胃排空试验。结果 莫沙必利对FD症状的疗效与吗叮啉组相当 (P >0 .0 5 )。99MTc胃排空测定发现莫沙必利组治疗后的半排时间 (45 .0 5± 1 2 .2 1 )min缩短 ,1 2 0min残留率 (2 9.73%± 8.5 1 % )减少 (P <0 .0 5 ) ,两组病例未发现毒副反应。结论 莫沙必利对于FD疗效良好 ,对胃排空延迟有良好疗效 ,安全度高。  相似文献   
102.
本文从医学人才培养的高度,论述高校与附属医院建立非隶属关系的附属医院的过程、体会和思考,指出目前存在的问题和解决途径.对进一步深化临床教育教学改革具有重要意义.  相似文献   
103.
104.
105.
Between 5% and 25% of patients may experience persistent diplopia after surgery for retinal detachment. The complexity of the presentation poses a distinct challenge to both the retinal and the strabismus surgeon. Careful evaluation to determine factors contributing to the strabismus and assessment of fusional capabilities are essential before treatment. A combination of the appropriate surgical approach with nonsurgical adjuncts such as prisms or botulinum toxin is often successful in relieving symptoms.  相似文献   
106.
Urinary banzo[a]pyrene (BaP) metabolite levels were compared to human environmental exposure to BaP through inhalation and dietary ingestion to assess the predictive validity of the exposure biomarker. These measurements were made for 14 adult volunteers over 14 consecutive days, once during summer/fall, again during winter periods. Based on personal air monitoring, median potential inhalation doses of 11.0 and 2.3 ng/day were estimated for the winter and summer/fall studies, respectively. A median potential ingested dose of 176 ng/day, estimated from duplicate plate sampling, exceeded inhalation by 6-and 122-fold for the winter and summer/fall studies, respectively. Total urinary BaP metabolites were measured using a published reverse metabolism (BaP) method of analysis. Median rates of urinary BaP metabolite elimination for the winter and summer/fall studies were 121 and 129 ng/day, respectively. The changes in inhaled and ingested potential doses were regressed on the change in urinary metabolite elimination from week 1 to week 2 to test the predictive validity of the biomarker measurement. The regression was statistically significant (r = 0.620, p = 0.015, n = 25) when body weight was included and two extreme values were removed. Consistent with the exposure measurements showing diet as the dominant route of exposure, most of the variation in urinary metabolite elimination was explained by the ingested dose. It is concluded that the measurement of urinary BaP by reverse metabolism is qualitative and of marginal predictive validity as an exposure biomarker due to the method's low recoveries and the large unexplained variance.  相似文献   
107.
One of the major factors limiting the staging accuracy of conventional magnetic resonance imaging (MRI) for prostatic carcinoma, is the similarity in signal intensity between tumor and coexisting benign prostatic hyperplasia (BPH). As neovascularity is an independent indicator of pathological state, dynamic contrast-enhanced MRI may yield additional information. This study correlates the histopathological findings from 12 radical prostatectomy patients on a region-by-region basis, with pharmacokinetic modeling of dynamic contrast-enhanced (0.2 mmol dimeglumine gadopentetate/kg), fast multiplanar spoilt gradient-recalled echo images, using a two-compartment simplex minimization technique. Quantitative analysis demonstrated differences in the amplitude of the initial contrast upslope and contrast exchange rate between tumor and fibromuscular BPH (P<0.03 and P<0.03, respectively) and for the contrast exchange rate between tumor and fibroglandular BPH (P<0.04), providing improved delineation of intraprostatic tumor extent compared with conventional imaging techniques.  相似文献   
108.
109.
Isoprene, a major commodity chemical used in production of polyisoprene elastomers, has been shown to be carcinogenic in rodents. Similar to findings for the structurally related compound butadiene, mice are more susceptible than rats to isoprene-induced toxicity and carcinogenicity. Although differences in uptake, and disposition of isoprene in rats and mice have been described, its in vivo biotransformation products have not been characterized in either species. The purpose of these studies was to identify the urinary metabolites of isoprene in Fischer 344 rats and compare these metabolites with those formed in male B6C3F1 mice. After i.p. administration of 64 mg [14C]isoprene/kg to rats and mice, isoprene was excreted unchanged in breath ( approximately 50%) or as urinary metabolites ( approximately 32%). In rats isoprene was primarily excreted in urine as 2-hydroxy-2-methyl-3-butenoic acid (53%), 2-methyl-3-buten-1,2-diol (23%), and the C-1 glucuronide conjugate of 2-methyl-3-buten-1,2-diol (13%). These metabolites are consistent with preferential oxidation of isoprene's methyl-substituted vinyl group. No oxidation of the unsubstituted vinyl group was observed. In addition to the isoprene metabolites found in rat urine, mouse urine contained numerous other isoprene metabolites with a larger percentage (25%) of total urinary radioactivity associated with an unidentified, polar fraction than in the rat (7%). Unlike butadiene, there was no evidence that glutathione conjugation played a significant role in the metabolism of isoprene in rats. Because of the unidentified metabolites in mouse urine, involvement of glutathione in the metabolism of isoprene in mice cannot be delineated.  相似文献   
110.
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