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   20075篇
  免费   2047篇
  国内免费   82篇
耳鼻咽喉   165篇
儿科学   590篇
妇产科学   509篇
基础医学   2701篇
口腔科学   381篇
临床医学   2258篇
内科学   4088篇
皮肤病学   236篇
神经病学   2059篇
特种医学   1004篇
外科学   2827篇
综合类   384篇
一般理论   14篇
预防医学   1884篇
眼科学   283篇
药学   1233篇
中国医学   7篇
肿瘤学   1581篇
  2021年   270篇
  2020年   174篇
  2019年   276篇
  2018年   317篇
  2017年   238篇
  2016年   269篇
  2015年   291篇
  2014年   401篇
  2013年   703篇
  2012年   876篇
  2011年   942篇
  2010年   526篇
  2009年   602篇
  2008年   834篇
  2007年   918篇
  2006年   857篇
  2005年   929篇
  2004年   852篇
  2003年   797篇
  2002年   775篇
  2001年   636篇
  2000年   661篇
  1999年   616篇
  1998年   320篇
  1997年   293篇
  1996年   319篇
  1995年   245篇
  1994年   253篇
  1993年   233篇
  1992年   445篇
  1991年   434篇
  1990年   428篇
  1989年   463篇
  1988年   377篇
  1987年   381篇
  1986年   381篇
  1985年   348篇
  1984年   260篇
  1983年   220篇
  1982年   178篇
  1981年   153篇
  1980年   138篇
  1979年   219篇
  1978年   186篇
  1977年   149篇
  1976年   150篇
  1974年   178篇
  1973年   141篇
  1972年   152篇
  1971年   139篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
Cerebral Emboli during Cardiac Surgery in Children   总被引:7,自引:0,他引:7  
Background: Microemboli occur commonly during cardiac surgery in adults, and, when present, increase the risk of neuropsychological deficits. Their incidence and significance during correction of congenital heart disease is unknown. The authors hypothesized that microemboli would occur before bypass with right-to-left cardiac shunts and would also occur in large numbers when the aortic crossclamp was released in children during repair of congenital heart defects.

Methods: In 25 children studied with carotid artery Doppler, embolic signals were counted and timed in relation to 13 intraoperative events. Patients were classified as either at high risk (obligate right-to-left shunt or uncorrected transposition of the great arteries) or at low risk (net left-to-right shunt or simple obstructive lesions) for paradoxical (venous to arterial) emboli.

Results: The median number of emboli detected was 122 (range, 2-2,664). Forty-two percent of all emboli were detected within 3 min of release of the aortic crossclamp. The high-risk group had significantly more emboli (median, 66; range, 0-116) during the time interval before cardiopulmonary bypass than did the low-risk group (median, 8; range, 0-73), with P < 0.01. There was no significant difference between the high-and low-risk groups in the total number of emboli detected. There was no apparent association between number of emboli and gross neurologic deficits.  相似文献   

33.
34.
Percutaneous transluminal coronary angioplasty (PTCA) of heavily calcified rigid coronary arteries has decreased success and increased complication rates. Three cases are presented describing a new technique for the dilatation of severely calcified coronary arteries that were not dilatable by conventional angioplasty methods. This technique involves the use of a balloon dilatation catheter system parallel to a guide wire. © 1993 Wiley-Liss, Inc.  相似文献   
35.
Alcohol and the adolescent trauma population   总被引:4,自引:0,他引:4  
Trauma is the leading killer of children and adolescents between 1 and 21 years of age. Alcohol-impaired driving represents the single greatest cause of mortality and morbidity of children over the age of 6. We retrospectively reviewed 878 consecutive adolescent (age range, 16 to 20 years) trauma admissions for blood alcohol concentration (BAC). Four hundred sixty-seven patients had BAC drawn, 258 were BAC-negative (group I), 209 (48%) were BAC-positive (group II). The adolescent drinkers were then compared with a group of 748 adult drinkers (group III). Groups I and II differ in sex, age, time of day of the accident, Injury Severity Score, Glasgow Coma Score, and Revised Trauma Score, whereas group II and III differ by type of accident, type of injury, socioeconomic factors (bad debt), time of day of the injury, and BAC. There were no significant differences in TRISS predicted survival, actual survival, nor mean length of stay. We conclude that (1) alcohol is a significant contributor to injury during adolescence, and (2) adolescent drinkers differ from adult drinkers in their habits, demographics, and socioeconomic status. These socioeconomic differences have implications for the access to and cost-effectiveness of interventions.  相似文献   
36.
A 25–year-old woman was admitted to the hospital because of rising trough cyclosporine concentrations thought to be due to self-administration of 4 times the normal dosage of the drug for 8 days. Her symptoms included colicky central abdominal pains and urinary retention; her serum creatinine concentrations were elevated. Whole blood cyclosporine and metabolite concentrations were measured by high-performance liquid chromatography and monoclonal radioimmunoassays. The highest reported trough cyclosporine concentration was 5877 ng/ml, and AM1 (M17) concentration was 3425 ng/ml. A cyclosporine half-life of 91 hours was calculated. Nine days after the agent was discontinued the patient's serum creatinine concentration had returned to normal and her symptoms resolved. Due to the availability of three sizes of cyclosporine capsules, and the need for frequent dosage changes, continued vigilance is necessary to ensure that patients understand their drug regimen.  相似文献   
37.
University of Wisconsin solution is currently recognized as the best solution for long-term organ preservation. It is recommended that UW solution be used as the in situ flush prior to organ explantation. The purpose of our study was to determine if hepatic allograft function was impaired by flushing the graft in situ with Euro-Collins and later flushing the graft ex vivo with UW solution, prior to cold storage. Fifty-six donors were randomly assigned to either an EC (n = 24) or UW (n = 32) in situ flush. The livers flushed with EC in situ were later flushed with 1 L of UW on the back table and stored in UW solution. Livers flushed with UW in vivo were similarly flushed and stored in UW on the back table. Concerning the donor allograft, there was no statistical difference (P greater than 0.05) between groups in sex, race, blood type, arterial anatomy, age, prothrombin time (PT), partial thromboplastin time (PTT), total bilirubin (TBR), direct bilirubin (DBR), aspartate amino transferase (AST), or alanine amino transferase (ALT). In addition, the recipients were compared for differences in sex, race, blood type, preoperative status, number of rejections, recipient age, length of surgery, and ischemia time and patient survival. There was no significant difference between groups (P greater than 0.05). There was no significant difference in patient survival (P = 0.238). Values for TBR, AST, ALT, PT, PTT, and AP were collected immediately preoperatively and postoperatively and on postoperative days 1, 3, 7, 14, and 28. There was no difference between groups in these values (P greater than 0.05). In our study there was no difference between the groups with respect to graft performance. This would justify the use of EC as an in situ flush during solid organ procurement and flushing with UW solution on the back table with an estimated savings of $400 to $1200 per procurement.  相似文献   
38.
Background: Morbid obesity is a serious disease that afflicts over five million Americans, threatening their health with such co-morbidities as diabetes, arthritis, pulmonary failure and stroke. Surgery is the only effective therapy, providing long-term control of weight, diabetes, pulmonary failure, and hypertension for as long as 14 years. Because the operation presents a major expense, this study examined whether X-ray examination of the gut could be omitted safely as a cost-saving measure. Methods: The records of 814 consecutive morbidly obese patients who underwent gastric bypass were reviewed to determine: (1) whether these individuals had undergone an upper gastro-intestinal (GI) series, and (2) if these studies influenced therapy or caused cancellation or postponement of surgery. Results: Of the 814 patients, 657 (80.7%) underwent a preoperative GI radiography. Of these examinations, 393 (59.8%) were normal, with the following abnormalities in the remaining 264: hiatal hernia, 164; esophageal reflux, 39; Schatzki's ring, 18; small bowel diverticula, four; renal stones, four; malrotation, three; gall stones, two; pyloric ulcer, one; possible pelvic mass, one; calcified leiomyoma, one; and dysphagial lusoria, one. None of these findings resulted in cancellation or a delay in surgery. Conclusions: The upper GI series can be safely omitted from the routine preoperative evaluation of patients undergoing gastric bypass. At a cost of $741.00 per examination, this change represents significant potential savings. Similar evaluations of other routine preoperative tests may well provide a better basis for the evaluation of these complex patients.  相似文献   
39.
In 1987, die Department of Health in the UK set up a working party to identify reasons contributing to a shortfall in donor organs. One recommendation was reimbursement to the District Health Authorities for costs incurred in providing the donor organs. The figure chosen was not to be seen as an incentive to donate organs, merely as an appropriate compensation for the costs incurred. There would be no direct payment to doctors, trustees or relatives of the donor. With the development of the competitive health care environment in the United Kingdom, the reimbursement of donating hospital costs is being considered with these data.  相似文献   
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