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   11175篇
  免费   375篇
  国内免费   69篇
耳鼻咽喉   49篇
儿科学   400篇
妇产科学   250篇
基础医学   739篇
口腔科学   174篇
临床医学   737篇
内科学   2715篇
皮肤病学   172篇
神经病学   541篇
特种医学   211篇
外科学   1588篇
综合类   804篇
一般理论   5篇
预防医学   1749篇
眼科学   210篇
药学   796篇
  2篇
中国医学   238篇
肿瘤学   239篇
  2023年   107篇
  2022年   207篇
  2021年   315篇
  2020年   307篇
  2019年   752篇
  2018年   643篇
  2017年   384篇
  2016年   207篇
  2015年   223篇
  2014年   441篇
  2013年   447篇
  2012年   384篇
  2011年   419篇
  2010年   331篇
  2009年   318篇
  2008年   308篇
  2007年   297篇
  2006年   244篇
  2005年   176篇
  2004年   107篇
  2003年   120篇
  2002年   87篇
  2001年   93篇
  2000年   92篇
  1999年   60篇
  1998年   54篇
  1997年   43篇
  1996年   41篇
  1995年   38篇
  1994年   39篇
  1993年   41篇
  1992年   27篇
  1991年   28篇
  1989年   17篇
  1988年   22篇
  1987年   19篇
  1986年   17篇
  1985年   285篇
  1984年   483篇
  1983年   401篇
  1982年   400篇
  1981年   340篇
  1980年   316篇
  1979年   390篇
  1978年   283篇
  1977年   195篇
  1976年   283篇
  1975年   249篇
  1974年   255篇
  1973年   243篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
31.
活动翼矫治器的研制与初步应用   总被引:2,自引:0,他引:2  
陈启锋 《口腔正畸学》2006,13(4):182-186
目的评价活动翼矫治器的设计原理与矫治效能。方法应用活动翼矫治器对588例错畸形病例进行矫治。对2001年~2004年的389例进行研究,分析其疗效、疗程、复诊次数、弓丝使用等情况。结果病例完成时间为4~15个月,平均为8.13个月。复诊次数4~13次,平均7.55次。平均每例上颌使用弓丝1.95根、下颌1.98根。仅11例病例使用口外支抗。结论活动翼矫治器是一种新研发的高效能矫治器,能够明显缩短疗程、减少复诊次数、减少弓丝用量  相似文献   
32.
Seven hundred and twenty-three serum samples from individuals in 13 Gidra-speaking villages in Western Province, Papua New Guinea were tested for evidence of infection with human T- lymphotropic virus type I (HTLV-I), human immunodeficiency virus type I (HIV-I), hepatitis B virus (HBV) and hepatitis C virus (HCV). No samples were positive for antibodies to HIV-I. Antibodies to HTLV-I were found in 13 samples (1.8%), HBV surface antigens (HBsAg) were found in 86 samples (11.9%), and antibodies to HCV were found in 30 samples (4.1%). Six (46.2%) of 13 HTLV-I positive samples were positive for HCV or HBsAg. The seropositive rate varied in different villages and the incidence of HTLV-I and HCV was higher in coastal and riverine areas than inland.  相似文献   
33.
A new method for estimating relative efficacies and relative intrinsic efficacies of agonists is described. Relative efficacy is estimated by employing a newly defined efficacy related parameter (eES) and it may be estimated without prior knowledge of efficacy values or the value of the equilibrium dissociation constants, KA, of agonist-receptor complexes. The parameter eES is directly related to efficacy (e) and is defined as the ratio of maximal stimulus to maximal effect of an agonist. The value of eES indicates whether or not spare receptors are present for a particular agonist–effector system. The eES values of agonists are estimated by utilizing submaximal concentration–effect curves determined with fixed agonist-competitive antagonist concentration combinations and choosing a suitable reference (height of an agonistic concentration–effect curve) to which the height of the stimulus concentration–effect curves of the agonist may be compared. In addition to eES, other new agonist–effector parameters, namely SEm/Sm and φmin, were also defined.  相似文献   
34.
In many examinations, communication skills tend to be treated as if they are a single attribute independent of the context of the communication. However, it is clear that such assessments are confounded by candidates' knowledge or lack of knowledge of the medical issues about which they are communicating. In the 1990 Part One examination for Membership of the Royal New Zealand College of General Practitioners candidates were provided with all the essential knowledge relevant to the problem they were to communicate about. Despite this, performance was still seen to be context specific, demonstrating that such specificity is not purely knowledge related. Candidates completing the examination were observed to share information about the cases with candidates about to commerce. There was no evidence that performance was enhanced by such breaches in examination security.  相似文献   
35.
本实验将赖型钩端螺旋体(简称钩体)DNA基因库的克隆pCX7制备成 ̄(32)P-重组DNA探针,对8个不同血清群的17株问号状钩体、双曲钩体PatocⅠ株以及细螺旋体3055株DNA进行打点杂交;同时用15种DNA片断进行限制性内切酶谱分析。结果表明,该重组DNA具有问号状钩体种(Species)特异性,但与不同问号状钩体之间的同源性程度有差别;限制性内切酶谱分析发现pCX7重组DNA片段长约1.7kb,具有1个Bg1Ⅱ识别位点和3个BstB1识别位点。  相似文献   
36.
作者以1%乙酸冲洗SD大鼠子宫内膜,获得子宫内膜酸溶性提取物。利用琼脂糖弥散法和电泳凝胶琼脂糖弥散法抗菌试验发现,子宫内膜提取物有三条主蛋白带对致病性大肠杆菌ML-35P耐药株有强抗菌活性,这三条抗菌蛋白带命名为RatUP-1,RatUP-2和RatUP-3,分别占子宫内膜提取物总蛋白量的4.5%,5.7%和6.6%。虽然提取物存在溶菌的活性,但其含量甚微,在AU一PAGE图谱上亦未能显现溶菌酶条带。本实验的结果提示子宫内膜合成一类抗菌多肽,可能在子宫抗菌机制中发挥重要作用。  相似文献   
37.
Summary A new liposuction cannula which can be used both with the syringe and with the machine has been produced by the author.  相似文献   
38.
In in vitro and animal experiments the tissue effects of the 1.318m Nd-YAG laser were compared to those of the standard 1.064m Nd-YAG laser in order to evaluate the advantages of the new wavelength with a ten times higher absorption in water for gastroenterological tumour treatment. Under irradiation parameters related to clinical endoscopic practice, the laser of the wavelength 1.318m needs for both vaporization and coagulation significantly less energy than the 1.064m laser. Since vaporization at 1.318m is always accompanied by a higher coagulation effect compared to 1.064m the risk of late necrosis and resulting perforation appears to be increased.  相似文献   
39.
40.
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