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   227958篇
  免费   7367篇
  国内免费   2831篇
耳鼻咽喉   3039篇
儿科学   7982篇
妇产科学   6287篇
基础医学   28666篇
口腔科学   6525篇
临床医学   19560篇
内科学   39827篇
皮肤病学   4834篇
神经病学   12843篇
特种医学   11733篇
外国民族医学   112篇
外科学   32662篇
综合类   7182篇
现状与发展   7篇
一般理论   3篇
预防医学   18665篇
眼科学   5390篇
药学   17317篇
  24篇
中国医学   2249篇
肿瘤学   13249篇
  2022年   1603篇
  2021年   2019篇
  2020年   1633篇
  2019年   1261篇
  2018年   4735篇
  2017年   5068篇
  2016年   4254篇
  2015年   6513篇
  2014年   6345篇
  2013年   5310篇
  2012年   12488篇
  2011年   7489篇
  2010年   4124篇
  2009年   5419篇
  2008年   3958篇
  2007年   4548篇
  2006年   4732篇
  2005年   12497篇
  2004年   13667篇
  2003年   9080篇
  2002年   4196篇
  2001年   4985篇
  2000年   2316篇
  1999年   6448篇
  1992年   7060篇
  1991年   7250篇
  1990年   7461篇
  1989年   7045篇
  1988年   6578篇
  1987年   6339篇
  1986年   6042篇
  1985年   5306篇
  1984年   3613篇
  1983年   2934篇
  1982年   1011篇
  1979年   3840篇
  1978年   2362篇
  1977年   1781篇
  1976年   1560篇
  1975年   2475篇
  1974年   3105篇
  1973年   2738篇
  1972年   2757篇
  1971年   2742篇
  1970年   2556篇
  1969年   2464篇
  1968年   2238篇
  1967年   2164篇
  1966年   1898篇
  1965年   1131篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
N-3 fatty acid deficiency is described in a 7-year-old girl who had been fed solely by gastric tube from the age of 3 years. She had received the same nutrient during the last 22 months, supplying 16.2% of calories from linoleate and 0.07% from alpha-linolenate. She weighed 9.5 kg at the age of 3, and 10.3 kg at the start of the study, the weight being constant the last 15 months. She was now supplemented daily with 1.2 ml of a linseed- and cod liver-oil mixture (5:1, v/v), thereby increasing her alpha-linolenate intake to 0.71% and total N-3 fatty acids to 0.74% of total energy. Two months later, her rate of weight gain was 0.43 kg/month. After 5 months, the fatty acid supplement was changed to 7.5 ml of cod liver oil daily, thereby changing alpha-linolenate and total N-3 acid intake to 0.10% and 1.3% of total energy, respectively. Her rate of weight gain now increased to 0.64 kg/month, and her length increased from 117 to 122 cm in 5 months. The results indicate that the optimal dietary requirement for N-3 fatty acids in this child is higher than 0.74%, and extrapolation estimated the optimal requirement to be 1.1%-1.2% of total calories. The results suggest that N-3 fatty acids are required for normal growth in man.  相似文献   
93.
94.
The relationship between energy expenditure and body composition, in terms of fat and fat-free masses, has previously been described by a variety of predictive regression equations with parameters devoid of physiological content. We present here results obtained by calculating the specific energy expenditure, ie, the energy expenditure per unit of mass, of fat and fat-free tissue on the basis of measurements of the total energy expenditure (EE), the masses of fat (FM), and fat-free (FFM) tissue using the following simple model: EE = k1.FM + k2.FFM where k1 and k2 are the specific energy expenditures of fat and fat-free tissue, respectively. The results of observations on 104 women at rest yielded values for k1 and k2 of 0.31 and 1.35 watts/kg of fat and fat-free mass, respectively, with standard errors of estimate of 0.074 and 0.052 watts/kg, respectively. Analysis of several series of measurements, from other sources and on smaller samples of subjects, yielded similar values at rest but with larger standard errors of estimate. Data from subjects performing varying amounts of work in 24-h measurements showed, as expected, larger values for both tissues. The results explain to a very large extent the well-established relation between resting metabolic rate and body weight, ie, a linear relation with a non-zero intercept. The results also offer a clear-cut explanation for the well known difference in energy expenditure between men and women with the same body weight.  相似文献   
95.
阐述了整体护理模式病房建设计算机管理系统的应用及效能:①促进了整体护理工作的开展。②高效率地体现了护理程序的全程。③使各种护理文件及护理表格达到清晰、美观、格式规范。④有利于科研、教学工作的完善。⑤推动了护理学科计算机技术的应用  相似文献   
96.
目的探讨p16基因突变在白血病发生中的作用及基因突变的机制。方法利用点突变检测仪、水平和垂直板电泳对p16基因的外显子1、外显子2的PCR扩增产物作缺失和点突变分析。结果在白血病35例临床标本中有22例发生缺失突变,6例发生点突变,突变率约80%。在22例缺失突变病例中,有10例为不完全缺失突变即有低于外显子509bp的扩增产物。结论p16基因含有“GC”DNA重复顺序,易发生DNA重组及易位和重排。在白血病发生中起重要作用  相似文献   
97.
本文选择34颗有银汞充填体悬突的患牙,采用金刚砂钻和银汞磨光钻去除悬突,并观察去除悬突前后部分牙周组织的变化、结果表明银汞充填体悬突危害牙周组织的健康.去除悬突并协同口腔卫生宣教、可促进牙周组织的恢复.  相似文献   
98.
Eleven patients with lunatomalacia were treated by excision of the lunate and instillation of liquid silicone. The silicone vulcanised and formed an in-situ molded prosthesis. The patients were reexamined after a mean of 7.1 years. Four patients were pain-free and two had pain only at work; three had not been improved by the operation and two had undergone arthrodesis. The patients with good results all belonged to group IV pre-operatively. Surprisingly, no patient showed any sign of silicone synovitis, although all the prostheses except one had either fractured or deformed. The reasons for this are discussed and the indications for the operation established.  相似文献   
99.
86对母婴血清标本用间接酶联免疫测定法(ELISA)测定了乙型脑炎抗体,118对用血凝抑制(血抑)试验测定了麻疹抗体。结果发现,脐血乙型脑炎抗体阳性率为79.1%,母血为74.4%,几何平均滴度在脐血显著高于母血(t=5.1857,P<0.01),比值为1.2∶1。脐血和母血的麻疹血抑抗体阳性率分别为86.4%及84.8%,几何均值也是前者高于后者(t=4.0349,P<0.01),比值为1.3∶1。 108份婴儿血清标本测定结果显示,0~3个月婴儿乙型脑炎抗体阳性率为35%,4~9个月仅为13%,10个月及以上的婴儿全部阴性。此结果与近年上海市小于1岁组乙型脑炎发病率最高相一致,提示应考虑提早乙型脑炎疫苗的接种年龄。  相似文献   
100.
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