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   7398篇
  免费   645篇
  国内免费   17篇
耳鼻咽喉   51篇
儿科学   289篇
妇产科学   240篇
基础医学   1170篇
口腔科学   137篇
临床医学   773篇
内科学   1513篇
皮肤病学   141篇
神经病学   795篇
特种医学   158篇
外科学   731篇
综合类   121篇
一般理论   9篇
预防医学   896篇
眼科学   162篇
药学   473篇
中国医学   12篇
肿瘤学   389篇
  2023年   43篇
  2022年   96篇
  2021年   171篇
  2020年   89篇
  2019年   147篇
  2018年   158篇
  2017年   148篇
  2016年   125篇
  2015年   162篇
  2014年   221篇
  2013年   290篇
  2012年   496篇
  2011年   489篇
  2010年   255篇
  2009年   229篇
  2008年   395篇
  2007年   456篇
  2006年   413篇
  2005年   385篇
  2004年   409篇
  2003年   342篇
  2002年   329篇
  2001年   132篇
  2000年   91篇
  1999年   140篇
  1998年   75篇
  1997年   62篇
  1996年   65篇
  1995年   49篇
  1994年   56篇
  1993年   42篇
  1992年   84篇
  1991年   63篇
  1990年   62篇
  1989年   61篇
  1988年   67篇
  1987年   68篇
  1986年   83篇
  1985年   72篇
  1984年   66篇
  1983年   52篇
  1982年   51篇
  1981年   55篇
  1980年   38篇
  1979年   61篇
  1978年   41篇
  1977年   42篇
  1976年   35篇
  1974年   34篇
  1973年   42篇
排序方式: 共有8060条查询结果,搜索用时 10 毫秒
1.
2.
Occipital spur is an abnormal bony outgrowth of the external occipital protuberance (EOP). We describe an interesting and previously unreported case of fracture of an occipital spur following trauma. Our 20-year-old male patient was treated in the emergency department (ED) and discharged home without complication. Neurosurgical consultation was obtained but is not requisite for these injuries. Greater awareness of this unique presentation may help to expedite future emergency department treatment.  相似文献   
3.
4.
Abstract Several methods have been used to predict successful weaning and extubation among chronic obstructive pulmonary disease (COPD) patients. The objective of this study is to determine whether carbon dioxide recruitment threshold (PCO2RT) can be used as adjunct to conventional weaning parameters to predict early weaning and successful extubation. Twelve COPD patients who were ready to be extubated based on conventional weaning parameters were divided into group A ( n = 7) and group B ( n = 5). Group A were those patients with better weaning parameters and hence a higher probability of successful extubation as compared to group B. Carbon dioxide apnoeic threshold (PCO2AT) was obtained by hyperventilating the patient using an increment of two breaths per min until apnoea occurs. At this point, the PCO2AT or the PaCO2 during said apnoeic period was recorded. A dead space of 150 cc is then added to the circuit until the patient starts to breathe as evidenced by the sensitivity trigger indicator. The PCO2 obtained at this period is termed PCO2RT. After weaning for 30 min on a T-tube, another arterial blood gas is determined and this is called the PCO2SB or the CO2 level after 30 min on spontaneous breathing. If the PCO2SB-PCO2RT difference is high with a sensitivity of 85.71% and specificity of 100% vs sensitivity of 57.14% and specificity of 60% using the conventional weaning parameters. Thus an increase in PCO2SB at 30 min T-tube is indicative of impending respiratory pump failure and that other causes of failure to wean must be investigated.  相似文献   
5.
BACKGROUND: In 1998, the UK government issued precautionary advice that pregnant or breast-feeding women with a family history of atopy, may wish to avoid eating peanuts during pregnancy and lactation. This study aimed to assess the compliance with this recommendation and investigate its impact upon peanut sensitization. METHODS: A total of 858 children born immediately after the advice were followed for 2 years and assessed for peanut sensitization. A standardized questionnaire was used to ascertain history of atopy and maternal exposure to peanuts during pregnancy. Following parental consent children were skin prick tested to assess sensitization to peanuts. RESULTS: Sixty-five per cent of mothers had avoided peanuts during pregnancy. Forty-two per cent of the mothers had heard about the government advice, and half modified their diet as a consequence. Neither maternal nor family history of atopy had any significant effect on peanut consumption. Parity did play a role, and mothers having their first child were twice as likely to change their diet (P<0.001). Mothers of 77% of the children sensitized to peanuts had avoided peanuts during pregnancy. In this cohort study maternal consumption of peanut during pregnancy was not associated with peanut sensitization in the infant. CONCLUSIONS: The majority of mothers in this cohort avoided peanut consumption during pregnancy. It is likely that either the government advice is misunderstood by mothers, or that those who communicate the advice have not fully explained who it is targeted at.  相似文献   
6.
7.
8.
Abstract: Transgenic expression of the human complement regulatory molecule CD59 in mice and genetic deletion of the major xenoantigen galactose α 1,3 galactose (Gal KO) each resulted in partial protection of spleen cells from lysis by human serum. These protective effects were additive when the two genetic modifications were combined. However, when the effects of these genetic modifications were examined in an ex vivo model in which mouse hearts were perfused with human plasma, it was Gal KO which was the modification which determined protection. CD59 expression alone was not protective and CD59 expression in combination with Gal knockout did not result in a significant additional increase in protection over and above that provided by Gal knockout alone. The likely explanation for this discrepancy between the in vitro and ex vivo data is that the H2-Kb promoter used to drive CD59 expression results I in substantially less expression on endothelium than on spleen cells.  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