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   1857篇
  免费   248篇
  国内免费   12篇
耳鼻咽喉   10篇
儿科学   78篇
妇产科学   49篇
基础医学   206篇
口腔科学   17篇
临床医学   190篇
内科学   438篇
皮肤病学   27篇
神经病学   136篇
特种医学   186篇
外科学   175篇
综合类   71篇
一般理论   3篇
预防医学   283篇
眼科学   21篇
药学   144篇
中国医学   6篇
肿瘤学   77篇
  2023年   10篇
  2021年   27篇
  2020年   12篇
  2019年   19篇
  2018年   25篇
  2017年   20篇
  2016年   40篇
  2015年   66篇
  2014年   39篇
  2013年   60篇
  2012年   66篇
  2011年   77篇
  2010年   68篇
  2009年   59篇
  2008年   102篇
  2007年   84篇
  2006年   82篇
  2005年   95篇
  2004年   83篇
  2003年   49篇
  2002年   90篇
  2001年   66篇
  2000年   52篇
  1999年   49篇
  1998年   37篇
  1997年   47篇
  1996年   46篇
  1995年   41篇
  1994年   36篇
  1993年   39篇
  1992年   37篇
  1991年   34篇
  1990年   40篇
  1989年   56篇
  1988年   43篇
  1987年   31篇
  1986年   29篇
  1985年   27篇
  1984年   25篇
  1983年   22篇
  1982年   16篇
  1981年   16篇
  1980年   17篇
  1979年   18篇
  1978年   10篇
  1976年   17篇
  1974年   8篇
  1971年   8篇
  1970年   14篇
  1968年   14篇
排序方式: 共有2117条查询结果,搜索用时 15 毫秒
41.
G Cullingford  B Davidson  J Dooley  N Habib 《HPB surgery》1991,3(2):129-34; discussion 134-7
Biliary tract abnormalities occur in about one of every three people, usually being minor and of no clinical significance. Major abnormalities, however, may present in an unusual manner and provide a major hazard to the unsuspecting surgeon. A patient presenting with cholangitis without jaundice or abnormal liver function tests is reported. Endoscopic retrograde cholangiography failed to demonstrate any bile ducts in the right postero-lateral segments of the liver, the "naked segment sign". A percutaneous transhepatic cholangiogram demonstrated a stricture obstructing the right posterior segmental hepatic duct with hepatolithiasis above the stricture. At operation an anomalous vessel was found at the site of the stricture. This case highlights the unusual way in which biliary tract anomalies may present and the importance of adequate pre-operative investigation.  相似文献   
42.
Osteopathic manipulative treatment (OMT) is a defining feature of osteopathic medicine; however, use of OMT by osteopathic physicians is declining. Recent studies reveal that many osteopathic physicians are abandoning use of OMT as early as medical school. Current national efforts are aimed at reversing this trend by standardizing osteopathic medical records and clinical training in OMT. The authors found that a structured clinical curriculum in OMT taught to house staff significantly increased the percentage of patients who received osteopathic structural examinations and the percentage of patients who received OMT as part of their hospital care.  相似文献   
43.
KA Daly  RE Selvius  B Lindgren 《Pediatrics》1997,100(6):931-936
OBJECTIVES: To investigate maternal knowledge and attitudes about otitis media (OM) risk, to estimate the prevalence of risk factors in the first year of life, and to identify barriers to the reduction of risk factors (eg, formula feeding, day care attendance, and exposure to passive smoke). METHODS: Questionnaires mailed to a systematic sample of 504 Minnesota women >/=18 years old identified through 1994 birth certificates. RESULTS: Eighty percent returned a completed survey. According to maternal report, 29% of infants (age 8 to 13 months) had recurrent OM (>/=3 episodes) and 2% had tympanostomy tubes. Forty-six percent attended day care, 29% had >/=1 smoking parent, and 49% breastfed for 相似文献   
44.
We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.   相似文献   
45.
46.
47.
目的:验证二甲双胍治疗抗精神病药引起的血脂异常的疗效和安全性。方法:将两项随机、安慰剂的 对照研究纳入分析。共有201例服用抗精神病药物后出现血脂异常的首发精神分裂症患者,并将其分为1 000 mg/d 二甲双胍组(以下简称为二甲双胍组,n=103)和安慰剂组(n=98),观察24周。在基线、治疗后第12周和第24周进行 临床症状及体重、血糖、血脂等代谢指标的评估。结果:二甲双胍治疗后,二甲双胍组和安慰剂组之间低密度脂 蛋白胆固醇(low density lipoprotein cholesterol,LDL-C)的平均差异从基线时的0.16 mmol/L,降低到第24周结束时的 –0.86 mmol/L,降低了1.02 mmol/L,差异有统计学意义(P<0.01)。而24周结束时,二甲双胍组LDL-C≥3.37 mmol/L的 患者有25.3%,显著低于安慰剂组24周结束时的64.8%(P<0.01)。与安慰剂组相比,二甲双胍组的体重、体重指数、 胰岛素、胰岛素抵抗指数、总胆固醇、三酰甘油和高密度脂蛋白胆固醇也有显著变化,差异均有统计学意义(均 P<0.05)。治疗对体重和胰岛素抵抗的影响出现在第12周,并且在第24周进一步改善,但对改善血脂异常的作用在第 24周结束时才出现。结论:二甲双胍治疗对于改善抗精神病药物引起的血脂异常和胰岛素抵抗是有效的,并且改善 抗精神病药物诱导的胰岛素抵抗出现的时间早于降低血脂异常的时间。  相似文献   
48.
49.
50.
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