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   20549篇
  免费   1286篇
  国内免费   217篇
耳鼻咽喉   173篇
儿科学   355篇
妇产科学   335篇
基础医学   2930篇
口腔科学   684篇
临床医学   1895篇
内科学   5390篇
皮肤病学   249篇
神经病学   2088篇
特种医学   741篇
外科学   3021篇
综合类   79篇
一般理论   3篇
预防医学   1023篇
眼科学   263篇
药学   1625篇
中国医学   68篇
肿瘤学   1130篇
  2023年   131篇
  2022年   337篇
  2021年   576篇
  2020年   406篇
  2019年   512篇
  2018年   629篇
  2017年   463篇
  2016年   524篇
  2015年   601篇
  2014年   803篇
  2013年   990篇
  2012年   1550篇
  2011年   1590篇
  2010年   890篇
  2009年   808篇
  2008年   1242篇
  2007年   1333篇
  2006年   1158篇
  2005年   1234篇
  2004年   1118篇
  2003年   994篇
  2002年   956篇
  2001年   229篇
  2000年   231篇
  1999年   231篇
  1998年   240篇
  1997年   174篇
  1996年   133篇
  1995年   130篇
  1994年   117篇
  1993年   113篇
  1992年   147篇
  1991年   97篇
  1990年   89篇
  1989年   74篇
  1988年   73篇
  1987年   67篇
  1986年   69篇
  1985年   57篇
  1984年   54篇
  1983年   46篇
  1982年   41篇
  1981年   37篇
  1980年   38篇
  1978年   24篇
  1973年   24篇
  1970年   24篇
  1935年   21篇
  1925年   23篇
  1922年   22篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Bilateral discoid medial menisci is an extremely rare condition of the knee and it can be associated to other pathological findings, including anterior portion cyst formation. We report on the clinical features, radiographic findings, treatment and results of one patient who presented a bilateral medial discoid meniscus combined with posterior portion cyst of the left knee. To the best of the author’s knowledge, this is the first case of bilateral medial discoid meniscus associated with posterior portion cyst formation.  相似文献   
93.
Background: Remifentanil-induced secondary hyperalgesia has been documented experimentally in both animals and healthy human volunteers, but never clinically. This study tested the hypotheses that increased pain sensitivity assessed by periincisional allodynia and hyperalgesia can occur after relatively large-dose intraoperative remifentanil and that small-dose ketamine prevents this hyperalgesia.

Methods: Seventy-five patients undergoing major abdominal surgery were randomly assigned to receive (1) intraoperative remifentanil at 0.05 [mu]g [middle dot]kg-1 [middle dot]min-1 (small-dose remifentanil); (2) intraoperative remifentanil at 0.40 [mu]g [middle dot]kg-1 [middle dot]min-1 (large-dose remifentanil); or (3) intraoperative remifentanil at 0.40 [mu]g [middle dot]kg-1 [middle dot]min-1 and 0.5 mg/kg ketamine just after the induction, followed by an intraoperative infusion of 5 [mu]g [middle dot] kg-1 [middle dot] min-1 until skin closure and then 2 [mu]g [middle dot]kg-1 [middle dot]min-1 for 48 h (large-dose remifentanil-ketamine). Pain scores and morphine consumption were recorded for 48 postoperative hours. Quantitative sensory tests, peak expiratory flow measures, and cognitive tests were performed at 24 and 48 h.

Results: Hyperalgesia to von Frey hair stimulation adjacent to the surgical wound and morphine requirements were larger (P < 0.05) and allodynia to von Frey hair stimulation was greater (P < 0.01) in the large-dose remifentanil group compared with the other two groups, which were comparable. There were no significant differences in pain, pressure pain detection threshold with an algometer, peak flow, cognitive tests, or side effects.  相似文献   

94.
Older age is not considered a contraindication for liver transplantation, but age-related morbidity may be a cause of mortality. Survival and the incidence of the main post-transplant complications were assessed in 111 adult liver transplant recipients. They were divided in two groups according to their age (patients younger than 60 years, n=54; patients older than 60 years, n=57) and both groups were compared. Older patients were more frequently transplanted for hepatitis C (p= 0.03) and hepatocellular carcinoma (p= 0.05) and their liver disease was less advanced (Child-Pugh and MELD scores were significantly lower; p=0.004 and p=0.05, respectively). After transplantation, older patients had a significantly lower survival (p=0.02). Higher age was independently associated with mortality (hazard ratio for each 10-year increase: 2.1; 95% confidence interval: 1.1- 4.0; p=0.02). The incidence of de novo neoplasia and nonskin neoplasia were higher in older patients (p=0.02 and p =0.007, respectively). Malignancy was the cause of death in one patient younger than 60 years and in 12 patients older than 60 years (p =0.002). In multivariate analysis, a higher age and smoking were independently associated with a higher risk of dying of de novo neoplasia. In conclusion, older liver transplant recipients have a significantly lower survival than younger patients. Malignancy is responsible for this decreased survival.  相似文献   
95.
96.
PURPOSE: Controlling the cerebral and systemic hemodynamic responses to laryngoscopy and tracheal intubation may play a role in determining clinical outcome in pediatric neurosurgical patients. This study compared the effects of remifentanil and fentanyl on cerebral blood flow velocity (CBFV) and hemodynamic profile during laryngoscopy and tracheal intubation in children under sevoflurane anesthesia. METHODS: Sixty healthy children aged two to six years undergoing dental surgery under general anesthesia were enrolled. Each child was randomly assigned to receive a remifentanil or fentanyl infusion, at a rate of 0.75, 1.0, or 1.5 microg x kg(-1) x min(-1) after induction of anesthesia with 2% sevoflurane. Middle cerebral artery blood flow velocity was measured by transcranial Doppler (TCD) sonography. Once a baseline set of hemodynamic variables and TCD measurements were recorded, the opioid infusion was started. Measurements were taken at two-minute intervals, starting four minutes prior to laryngoscopy until four minutes following naso-tracheal intubation. RESULTS: Remifentanil caused a more significant decrease in mean arterial pressure and CBFV prior to tracheal intubation than did fentanyl (P < 0.001). During laryngoscopy and for two minutes following tracheal intubation, CBFV increased in all remifentanil groups (P < 0.05), whereas it remained stable in all fentanyl groups. CONCLUSION: This study suggests that fentanyl was more effective than remifentanil at preventing increases in CBFV during and immediately following laryngoscopy and tracheal intubation in children undergoing sevoflurane anesthesia. Fentanyl also seemed to provide a more stable hemodynamic profile prior to laryngoscopy and tracheal intubation when compared to remifentanil.  相似文献   
97.
98.
The records of two groups of patients (358 schizophrenics and 69 neurotics), attending the community mental health center of the Johns Hopkins Hospital, were reviewed to assess the extent and severity of reported medical problems. Results indicate that 38% of the schizophrenics and 53% of the neurotics report medical problems, but schizophrenics present with serious medical problems more often than do the neurotics. The authors draw attention to the need for properly assessing the severity of these medial problems and for adequately coordinating psychiatric and medical care. Strategies to overcome these difficulties are suggested.  相似文献   
99.
Academic Achievement of Children with Epilepsy   总被引:31,自引:23,他引:8  
The academic achievement scores of 122 children with epilepsy were examined in relation to demographic and clinical seizure variables. As a group, these children were making less academic progress than expected for their age and IQ level. Academic deficiencies were greatest in arithmetic, followed by spelling, reading, comprehension, and word recognition. Results of the multiple regression analyses indicated a modest combined predictive significance of the demographic and clinical seizure variables for academic performance. In addition, the magnitude of these relationships varied by academic area. Among the individual variables examined the strongest correlates of academic performance were age of the child, age of seizure onset, lifetime total seizure frequency, and presence of multiple seizures (absence and tonic-clonic). These results are discussed in relation to developing an understanding of the factors which underlie academic vulnerability in children with epilepsy.  相似文献   
100.
Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with hemostasis during the perioperative period, and the combination of NSAID and enoxaparin could increase this effect. The aim of this prospective, blinded experimental study was to assess these effects using a model of arterial thrombosis and bleeding in the rabbit.

Methods: After anesthesia was induced and monitors placed, the common carotid arteries were exposed, and 60% stenosis of the right common carotid artery was produced. Twenty minutes later, a compression injury of the artery was produced that triggered a series of cyclic episodes of thrombosis and clot lysis. This was manifested as cyclic flow reductions (CFR; measured with an electromagnetic flow meter). After the first flow reduction was noted, the rabbits were immediately and randomly assigned to one of four groups (n = 10 each) that received intravenous infusions: control, ketorolac (2 mg/kg), enoxaparin (0.5 mg/kg), and ketorolac plus enoxaparin (2 mg/kg and 0.5 mg/kg, respectively). The number of CFRs that occurred in the subsequent 20-min period was used as a measure of treatment effect. The contralateral common carotid artery was exposed, and both stenosis and injury were produced. The ability of the administered drug to prevent thrombosis was assessed as the number of CFRs that occurred during the first 20-min period after vessel injury. In addition, both before and after group assignment and drug injection, bleeding times were noted and a platelet aggregation test was performed. Laparotomy was followed by a spleen section, and the extent of the wound and the amount of splenic bleeding were measured.

Results: The treatment effect was indicated by the median number of CFRs, which was 5.5 in the control group, 1 in the ketorolac group, 2 in the enoxaparin group, and 0 in the ketorolac + enoxaparin group. The prevention effect was indicated by the median number of CFRs, which was 4 in the control group, 0 in the ketorolac group, 2 in the enoxaparin group, and 0.5 in the ketorolac + enoxaparin group. Bleeding time was significantly lengthened in the enoxaparin and in the ketorolac + enoxaparin groups. Splenic and wound bleeding was greater in the ketorolac group. Platelet aggregation was completely inhibited in the ketorolac and the ketorolac + enoxaparin groups.  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