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   30729篇
  免费   4741篇
  国内免费   68篇
耳鼻咽喉   575篇
儿科学   893篇
妇产科学   821篇
基础医学   3486篇
口腔科学   745篇
临床医学   4250篇
内科学   6555篇
皮肤病学   882篇
神经病学   2617篇
特种医学   1030篇
外国民族医学   2篇
外科学   5521篇
综合类   389篇
一般理论   13篇
预防医学   2805篇
眼科学   950篇
药学   1794篇
  3篇
中国医学   77篇
肿瘤学   2130篇
  2023年   763篇
  2022年   234篇
  2021年   562篇
  2020年   605篇
  2019年   468篇
  2018年   1048篇
  2017年   1013篇
  2016年   951篇
  2015年   950篇
  2014年   1339篇
  2013年   1487篇
  2012年   1457篇
  2011年   1559篇
  2010年   1175篇
  2009年   1216篇
  2008年   1299篇
  2007年   1224篇
  2006年   1286篇
  2005年   1150篇
  2004年   1210篇
  2003年   1143篇
  2002年   991篇
  2001年   895篇
  2000年   771篇
  1999年   777篇
  1998年   387篇
  1997年   326篇
  1996年   276篇
  1995年   285篇
  1994年   239篇
  1993年   232篇
  1992年   582篇
  1991年   562篇
  1990年   477篇
  1989年   538篇
  1988年   520篇
  1987年   488篇
  1986年   461篇
  1985年   484篇
  1984年   324篇
  1983年   298篇
  1982年   214篇
  1981年   188篇
  1979年   262篇
  1978年   202篇
  1977年   172篇
  1976年   180篇
  1974年   191篇
  1973年   208篇
  1971年   170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Adherence of bacteria to corneal epithelium is a prerequisite for corneal infection. We used two methods to study the binding of Pseudomonas aeruginosa and Staphylococcus aureus to rabbit corneal epithelial cells in culture. In the first method, rabbit corneal epithelial cells grown on glass slides were incubated with P. aeruginosa or S. aureus (10(7) CFU/ml) at room temperature for 90 min, and the bacterial binding to the epithelial cells was examined by light microscopy. Both P. aeruginosa and S. aureus bound to epithelial cells. P. aeruginosa was bound to the cell periphery whereas S. aureus was bound randomly to the cell surface. In the second method, suspension cultures of corneal epithelial cells were used. In contrast to the findings in cultures on slides, binding pattern with cells in suspension was similar for both species and resembled that for S. aureus in cultures on slides. A much greater number of P. aeruginosa (186 +/- 11 bacteria/epithelial cell) than S. aureus (30 +/- 1.5 bacteria/epithelial cell) bound to epithelial cells grown on glass slides. In contrast, a similar number of P. aeruginosa (25 +/- 5.1) and S. aureus (20 +/- 4.7) bound to epithelial cells grown in suspension cultures. Using either method, Escherichia coli and Streptococcus pyogenes did not bind significantly (less than 5/cell) to corneal epithelial cells. The above methods should prove useful for characterization of bacterial binding to corneal epithelial cells in culture.  相似文献   
72.
Seventeen consecutive patients were referred for management of empyema between April 1991 and March 1992. Fourteen patients defined as having an 'early' empyema were initially treated by videothoracoscopy. The other three patients, defined as having a 'late' empyema proceeded directly to thoracotomy. Videothoracoscopy was successful in 10 out of the 14 patients. The mean postoperative stay was 7.8 days. At a mean follow-up at 16.7 months, these patients were rendered apyrexial with full lung expansion and no residual pleural collection. The postoperative results were at least equivalent to other conventional forms of treatment without an undue level of complications. In this series, thoracoscopy was found to be successful when symptoms had been present up to 31 days before presentation at the first hospital, and the mean length of treatment before referral to Harefield was 47 days. It is now our policy to videothoracoscope all patients with empyema thoracis, regardless of the length of referral. It may circumvent the need for a thoracotomy, it does not add any increased risk of complications, and does not appreciably increase the length of hospital stay should thoracotomy ultimately be required.  相似文献   
73.
74.
Recent Hospital Transfusion Committee (HTC) audit at the Royal Bournemouth Hospital (RBH) confirmed an allogeneic red cell transfusion rate of 20% for primary Total Knee Replacement (TKR). Current policy at RBH states that when blood stocks reach 67% of normal (amber alert) then surgery with a >20% likelihood of blood transfusion will be cancelled. At current transfusion rates this would include primary TKR. Recent studies have shown a reduction in allogeneic transfusion rates when autologous transfusion drains are utilized. The purpose of this study was to see whether the current rate of allogeneic transfusion could be reduced with the introduction of the CellTransTM Autologous Knee Drainage Blood Transfusion System (ABT) in TKR at RBH. Over a 3 month period all patients undergoing primary, bilateral or revision knee arthroplasty received an ABT. Demographic data was collected from the orthopaedic pre‐assessment clinic. Following surgery further data was collected relating to volume of blood loss into the drain, volume of autologous blood re‐transfused, units of allogeneic blood required and the transfusion trigger, postoperative haemoglobin levels, infection rates and length of stay in hospital. We then compared this data set with retrospective data. Of 170 patients undergoing knee arthroplasty 141 received the ABT. The data collected was compared retrospectively with 169 patients from the previous 3 month period. We demonstrated a reduction in transfusion rates of 13% for primary TKR, 42% for bilateral TKR and 57% for revision TKR with the use of the ABT. In addition we demonstrated a reduction in total allogeneic blood use (99 units to 26 units) and a reduction in mean length of stay in hospital (8.6 days to 7.5 days) with the ABT. Further analysis of the data collected showed a 46% reduction in the allogeneic transfusion rate and a reduction in total allogeneic blood usage (99 units to 9 units) of anaemic patients presenting for surgery. This study has demonstrated a dramatic reduction in allogeneic blood transfusion rates with the use of the CellTransTM Autologous Blood Transfusion System. We have also shown a reduction in length of stay in hospital. Prior to the study primary total knee replacement would have been cancelled during times of limited blood availability (amber alert). The use of the ABT is good for the patient in reducing the need for allogeneic blood, and in addition has demonstrated a significant cost saving due to the reduced blood usage and potential prevention of cancelled operation lists.  相似文献   
75.
76.
This is a report of four complications from the use of an automated arthroscopy pump in 283 patients undergoing knee arthroscopy. The first patient had extravasation of fluid into the thigh, requiring discontinuation of the procedure. The second patient developed a compartment syndrome of the leg, necessitating a four-compartment fasciotomy of the leg. The third patient developed severe fluid extravasation into the anterior thigh compartment. A limited fasciotomy of the anterior thigh compartment was performed. The fourth patient developed moderate extravasation into the anterior part of the thigh and groin, necessitating discontinuation of pump irrigation and conversion to gravity irrigation to complete a partial medial meniscectomy. During a 15-month period, a complication rate of 1.4% from fluid extravasation during knee arthroscopy was noted. This review represents our initial experience with the infusion pump. No cases of fluid extravasation have occurred subsequently during a 12-month period.  相似文献   
77.
78.
Recent evidence suggests that a variety of hypothalamic neuropeptides may mediate interneuronal communication to coordinate diverse neuroendocrine and behavioral functions. In this work, we describe the effects of neuropeptide Y (NPY) on feeding and sexual behaviors. We observed that central administration of bolus NPY stimulated a robust, dose-related feeding response in satiated male and female rats. Continuous NPY receptor activation also evoked dose-related, intermittent feeding in a manner normally observed during nocturnal feeding. It appears that the paraventricular nucleus in the hypothalamus may be the primary site of NPY action because the anticipated reciprocal changes in NPY concentrations, in response to food deprivation followed by ad libitum food intake, occurred only in this site. Additional findings revealed that NPY-induced feeding may follow either substantial reduction or complete restraint of an inhibitory influence on feeding mediated by alpha 2-adrenoreceptor systems in satiated rats. Further, NPY was found to suppress male and female sexual behaviors. The suppressive effects on sexual behavior were apparent prior to or at the time of the onset of feeding after NPY administration. These observations may provide a neurochemical basis for clinical and animal studies on disorders of feeding associated with diminished reproductive functions.  相似文献   
79.
OBJECTIVE: To compare the rates of hospital admission for management of ovarian cysts in England and Wales and the United States between 1972 and 1974 and 1984 and 1986; and to determine whether these rates are related to rates of early diagnosis of ovarian cancer. DESIGN: Analysis of published and unpublished hospital discharge data based on national samples, the Hospital In-patient Enquiry (HIPE), a 10% hospital discharge sample for England and Wales, and the National Hospital Discharge Survey (NHDs), a 5% sample for the United States. MAIN OUTCOME MEASURES: Age-specific discharge rates for primary and secondary diagnoses of ovarian cyst or benign ovarian tumour. RESULTS: There was an age-adjusted increase in discharge rates of about 8% in both countries; discharge rates in the United States were approximately double those in England and Wales in both time periods. There was no difference in the rates of early diagnosis of ovarian cancer. CONCLUSIONS: Ovarian cysts are a common cause of hospital admission in both countries. The higher rates in the United States are not associated with earlier diagnosis of ovarian cancer.  相似文献   
80.
Since 1982 eight patients under 1 year of age with end-stage renal failure have been treated by chronic peritoneal dialysis (CPD) following insertion of an abdominal Tenckhoff catheter. We routinely perform a partial omentectomy now, and in males undertake bilateral exploration of the groins at the time of catheter insertion, with herniotomy or ligation of the patent processus vaginalis as required. Up to January 1990, 19 straight double-cuff catheters had been inserted with a total follow-up of 244.5 patient months. The median age at the initial catheter insertion was 14.6 weeks (range, 2 days to 11 months) and the median weight was 3.89 kg (range, 2.2 to 5.5). Peritonitis was the most common complication, with 46 episodes, representing one episode of peritonitis per 5.3 patient months on dialysis. The frequency of peritonitis has decreased in the last 6 months since all patients have been dialysed by two caregivers. The present rate of peritonitis is 1 episode per 10 patient months on dialysis. One patient has died of septicemia secondary to associated congenital abnormalities, one patient has regained renal function, and two patients have been transplanted, one successfully. Five patients are currently dialysing via their abdominal Tenckhoff catheters and awaiting transplantation. We conclude that neonates and infants under 1 year of age can be treated satisfactorily by CPD to enable successful preparation for transplantation later in childhood.  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