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   760篇
  免费   85篇
  国内免费   26篇
耳鼻咽喉   5篇
儿科学   20篇
妇产科学   13篇
基础医学   90篇
口腔科学   7篇
临床医学   109篇
内科学   183篇
皮肤病学   5篇
神经病学   30篇
特种医学   101篇
外科学   180篇
综合类   19篇
预防医学   38篇
眼科学   19篇
药学   32篇
肿瘤学   20篇
  2022年   6篇
  2021年   9篇
  2017年   8篇
  2016年   12篇
  2015年   10篇
  2014年   9篇
  2013年   13篇
  2012年   30篇
  2011年   25篇
  2010年   13篇
  2009年   17篇
  2008年   18篇
  2007年   29篇
  2006年   41篇
  2005年   26篇
  2004年   22篇
  2003年   27篇
  2002年   16篇
  2001年   21篇
  2000年   19篇
  1999年   17篇
  1998年   18篇
  1997年   9篇
  1996年   22篇
  1995年   19篇
  1994年   21篇
  1993年   11篇
  1992年   29篇
  1991年   25篇
  1990年   24篇
  1989年   44篇
  1988年   26篇
  1987年   30篇
  1986年   20篇
  1985年   22篇
  1984年   14篇
  1983年   15篇
  1982年   7篇
  1981年   11篇
  1980年   7篇
  1979年   6篇
  1978年   8篇
  1977年   10篇
  1975年   5篇
  1973年   5篇
  1972年   5篇
  1971年   7篇
  1969年   8篇
  1968年   6篇
  1967年   6篇
排序方式: 共有871条查询结果,搜索用时 0 毫秒
1.
Vitamin K was quantitated in the milk of four groups of 15 mothers from 1 d to 6 mo postpartum in a cross-sectional study. Concentrations were 7.52 +/- 5.90 and 6.36 +/- 5.32 nmol/L (3.39 +/- 2.66 and 2.87 +/- 2.40 micrograms/L) in colostrum and mature milk, respectively. Differences between colostrum and mature milk or among samples of mature milk collected at 1, 3, and 6 mo were not statistically significant. Because of significantly increased volumes of milk over the lactation period, approximately twice as much vitamin K was delivered in mature milk as in colostrum. Within normal ranges, concentrations of vitamin K in milk were not predicted by dietary intake of vegetables or fat. Vitamin K was correlated with fat in colostrum and was localized in the lipid core of the milk fat globule but was not associated with membranes. Vitamin K in human milk is insufficient to meet recommended intakes for infants aged less than 6 mo. Population and clinical studies are needed to assess the vitamin K status of exclusively breast-fed infants and to evaluate current recommendations.  相似文献   
2.
Transplant pneumonectomy is a rarely performed procedure. It is occasionally carried out in the course of retransplantation. To our knowledge, resection of a transplanted lung without its replacement and with successful outcome in the adult has not been previously reported. We present a case of elective left transplant pneumonectomy in a 38-year-old man 6 years after left single-lung transplant. At 12 months after resection, the patient remains well, with good exercise tolerance.  相似文献   
3.
4.
In order to compare an acceleromyograph (TOF-GuardTM) with a mechanomyograph (Grass FT03), the dose–response relationship of rocuronium was simultaneously determined in both arms of 15 children aged 3–11 years during anaesthesia with thiopentone, alfentanil and nitrous oxide. Three subgroups of five children received rocuronium 120, 180 or 240 μg.kg−1 randomly. The effective doses to produce 50% and 95% depression of the first twitch of the train-of-four determined by acceleromyography were 206 and 337 μg.kg−1, respectively, while these values determined by mechanomyography were 151 and 331 μg.kg−1, respectively. The dose–response curve obtained by acceleromyography was steeper and shifted to the right compared with that obtained by mechanomyography (p < 0.0001). The difference between the effective dose producing 50% twitch depression determined by the two devices was highly significant (p < 0.0001). In 13 out of 15 children, the acceleromyograph control train-of-four ratio was significantly greater than unity. Although there was a good correlation ( r  = 0.85) between simultaneous pairs of measurements of neuromuscular block, the acceleromyograph exhibited a bias of −25% relative to the mechanomyograph with wide limits of agreement (−62 to +12%). We conclude that acceleromyographic and mechanomyographic measurements should not be used interchangeably when determining the potency of muscle relaxants.  相似文献   
5.
In part I of this review the principles governing the uses of analgesics and sedatives in the ITU were considered. In part II we shall review the drugs available considering first, symptomatic therapy and secondly, regional analgesia.  相似文献   
6.
7.
The volume of milk produced by mothers who smoked cigarettes (n = 11) and control subjects who did not smoke (n = 29) was compared after the delivery of their preterm infants (28 to 32 weeks gestation). Milk production was significantly less among those who smoked, with or without adjusting for age, race, parity, gravidity, weight-for-height, prior nursing experience, customary alcohol and caffeine intake, infant birth weight, and pumping frequency. Each mother maintained her milk production using an electrical breast pump and without the stimulus of her infant suckling at the breast. Daily frequency and duration of breast pump usage were similar in the two groups. At 2 weeks postpartum, 24-hour milk volumes were 406 +/- 262 mL for mothers who smoked and 514 +/- 338 mL for control subjects. Between 2 to 4 weeks postpartum, the mean change in 24-hour milk volume (milliliters per 24 hours) of control subjects increased (+113 +/- 179 mL, P < .005), whereas milk volume of mothers who smoked cigarettes remained unchanged (-47 +/- 122 mL, P = .25). The percentage change in milk volume between 2 and 4 weeks for the combined groups was significantly related to four factors: pumping frequency, change in daily pumping frequency, day of initiation of pumping, and smoking status. Total and protein nitrogen, lactose, calcium, and phosphorous concentrations did not differ in milks from mothers who smoked cigarettes and mothers who did not smoke.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
A 317-bp segment of DNA from the 3' region of the human phosphoglucomutase-1 (PGMl) gene has been examined by a non-radioactive technique for the occurrence of single-strand conformation polymorphism (SSCP), Eight phenotypes were detected and attributed to the presence of four alleles. Genetic analysis of 75 unrelated individuals and six CEPH families whose PGMl protein phenotypes were known revealed strong association between the PGMl '+' and '−' isozyme phenotypes and the variation detected in this region, but no association with the PGMl 1 and PGMl 2 isozyme phenotypes. DNA sequence analysis demonstrated the presence of three nucleotide substitutions underlying the alleles, which were located in the untranslated region of the PGMl gene. There was complete correlation between the nucleotide sequence and the phenotype detected by SSCP analysis. This study provides support for the model that the PGMl isozyme polymorphism is determined at two distinct sites in the coding sequence, one coding for the '1' and '2' alleles and the other coding for the '+' and '−' alleles, separated by a region where intragenic recombination occurs.  相似文献   
9.
10.
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