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   9988篇
  免费   304篇
  国内免费   113篇
耳鼻咽喉   518篇
儿科学   1667篇
妇产科学   96篇
基础医学   375篇
口腔科学   160篇
临床医学   1224篇
内科学   875篇
皮肤病学   73篇
神经病学   680篇
特种医学   372篇
外科学   2264篇
综合类   608篇
预防医学   459篇
眼科学   103篇
药学   523篇
  6篇
中国医学   139篇
肿瘤学   263篇
  2023年   317篇
  2022年   482篇
  2021年   653篇
  2020年   473篇
  2019年   713篇
  2018年   690篇
  2017年   389篇
  2016年   340篇
  2015年   326篇
  2014年   814篇
  2013年   645篇
  2012年   477篇
  2011年   536篇
  2010年   388篇
  2009年   432篇
  2008年   422篇
  2007年   309篇
  2006年   283篇
  2005年   225篇
  2004年   122篇
  2003年   65篇
  2002年   51篇
  2001年   75篇
  2000年   75篇
  1999年   48篇
  1998年   48篇
  1997年   53篇
  1996年   40篇
  1995年   33篇
  1994年   31篇
  1993年   19篇
  1992年   17篇
  1991年   17篇
  1990年   21篇
  1989年   23篇
  1988年   14篇
  1986年   11篇
  1985年   69篇
  1984年   79篇
  1983年   54篇
  1982年   70篇
  1981年   64篇
  1980年   58篇
  1979年   58篇
  1978年   43篇
  1977年   32篇
  1976年   64篇
  1975年   36篇
  1974年   45篇
  1973年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Background: Recent data suggest that children have a higher incidence of recurrence than adults after nonoperative treatment of primary spontaneous pneumothorax (PSP). Video-assisted thoracoscopic surgery (VATS) allows efficacious therapy with significantly less morbidity. We attempt to define the most cost-effective clinically efficacious strategy using VATS to manage pediatric PSP. Methods: We retrospectively reviewed all admissions to a tertiary care children's hospital for PSP between January 1, 1991 and June 30, 1996. Results: Fifteen children had 29 primary or recurrent PSPs. Mean patient age was 14.8 ± 1.1 years, boy–girl ratio 4:1, median body mass index 18 (normal, 20–25), and 67% of pneumothoraces left sided. All patients were managed initially nonoperatively: 14 with tube thoracostomy drainage and 1 with oxygen alone. Of the children initially managed nonoperatively, 57% had a recurrent pneumothorax, and 50% of these patients eventually developed contralateral pneumothoraces. Nonoperative treatment for recurrence resulted in a 75% second recurrence rate. In contrast, eight children who underwent operative management had a 9% incidence of recurrence. The total for charges accrued in treating 29 pneumothoraces in these 15 patients was approximately $315,000. In the same population, the estimated charges for initial nonoperative therapy followed by bilateral thoracoscopy after a single recurrence would be $230,000. Conclusions: A cost-effective treatment strategy for pediatric primary spontaneous pneumothorax is tube thoracostomy at first presentation, followed by VATS with thoracoscopic bleb resection and pleurodesis for patients who experience recurrent pneumothorax. Received: 15 May 1998/Accepted: 15 January 1999  相似文献   
73.
Kim WG  Park SS 《Artificial organs》1999,23(4):369-372
A standardized system to describe the pressure-flow characteristics of a given cannula has recently been proposed and has been termed the M-number system. Using 3 different sizes of aortic cannulas in 50 pediatric cardiac patients on hypothermic cardiopulmonary bypass, we analyzed the correlation between experimentally and clinically derived M-numbers and found it to be positive. Clinical M-numbers were typically 0.35 to 0.55 greater than experimental M-numbers and correlated inversely with a patient's temperature change; this was most probably due to increased blood viscosity arising from hypothermia. This inverse relationship was more marked in higher M-number cannulas. The clinical data obtained in this study suggest that the experimentally derived M-number correlates strongly with the clinical performance of the cannula and that the influence of temperature is significant.  相似文献   
74.
Depending upon various factors the surgical procedures in childhood are divided into three groups—immediate, intermediate and elective. The timing of surgery is probably the most important factor governing the outcome of surgical correction in pediatric surgery. With continuing research and clinical experience our understanding of the various conditions have improved and with that has come a change in the optimum timing of many surgical procedures. This paper highlights the best timing of surgery for some of the commoner pediatric surgical procedures and the reasons behind these so that the children may be referred to pediatric surgeons in time.  相似文献   
75.
Respiratory diseases are a major cause of morbidity and mortality in developing countries. Recurrent respiratory infections in children pose a great challenge to the pediatrician where he has to exercise his clinical acumen and methodical, approach, for correct diagnosis and treatment. It is a fact that children should suffer 7 to 8 upper respiratory infections per year until they are 5 years of age when their immune status reaches adult level. In this situation, it is essential to find out whether the frequencies are abnormal. Whenever a child has the following, problems, then only it needs to be investigated.—(a) repeated bacterial pneumonias; (b) a child less than 3 months old having repeated respiratory infections; (c) a child of 9 months old without a history of exposure infections; (d) infections, complicating into bronchiectasis and; (e) in a child where there is no history of allergy or asthma. Once the problem is established as a true recurrent respiratory infection, the clinician should pose questions—whether it is chronic, acute or recurrent, to find out the site of pathology, seriousness of the problem, response to previous medications, to establish the possible diagnosis which fall into six categories—congenital anamolies, aspiration syndrome, genital disorders, immunological, diseases, immune deficiency disorders and allergic diseases. The author discusses quoting some examples for various categories avoiding non pulmonary causes for recurrent respiratory infections in children.  相似文献   
76.
77.
The emergence of surgery during the Renaissance marked the birth of surgery as a discipline based on clinical observation and improvement of technical skill. Some of the most experienced surgeons dealing with pediatric problems were Paré, Phaer, Würtz and, especially, Hildanus, who described more than 150 cases in children. Some minor malformations were curable, and some major anomalies were described for the first time. Renaissance surgeons had no explanations for the etiology of diseases and malformations. In many instances, the imaginatio was considered to be responsible.  相似文献   
78.
我院小儿神经学组近年来对癫痫及智力低下进行了综合研究。在整体动物及神经细胞水平研究了神经肽(CCK,Som)与神经递质(GABA)之间的关系;初步探讨了铁诱发癫痫的化学机制;研究了抗癫痫药对发育中脑的影响;用双盲交叉法观察了新药“抗病灵”的疗效;利用24小时脑电图从临床电生理角度进一步探讨了癫痫的发病机制,解决了癫痫难以观察的问题。还在全国范围内进行了智力低下的流行病学调查,并分析其原因。  相似文献   
79.
Fifteen infants and children (M = 7, F = 8), aged from 0 to 13 years, who underwent cardiac catheterization and cardioangiography under ketamine-diazepam anesthesia were the subjects of this study. The effect of a contrast medium, isolamate sodium (66.8%) on the plasma somolality and vasopressin concentration was studied. The plasma osmolality was significantly elevated after contrast medium administration (289 ± 3 vs. 303 ± 8mosmol·kg–1) as well as plasma vasopressin (from 2.1 ± 0.9 vs. 4.7 ± 2.0 micro-unit·ml–1).It is concluded that the administration of contrast medium for cardioangiography causes elevation of plasma osmolality, which leads to the elevation of plasma vasopressin concentration.(Yamashita M, Horigome H, Kudo T, et al.: Plasma vasopressin response to contrast medium during cardiac catheterization in infants and children. J Anesth 5: 203–204, 1991)  相似文献   
80.
Two newborn infants with duodenal and jejunal atresia and agenesis of the dorsal mesentery represent our surgical experience with "apple peel" small bowel or "christmas tree" demormity. The first patient had the typical appearance of this condition. The postoperative course was complicated by hyperbilirubinemia, septicemia, and disseminated intravascular coagulation. The infant is in satisfactory condition 1.5 years after operation. The second patient had agenesis of the dorsal mesentery without spiraling of the bowel around its vascular stalk. The child died after 1 month, with complete absence of extrahepatic bile ducts as seen at a second laparotomy. Neither child had been subjected to gastrostomy.  相似文献   
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