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   953篇
  免费   59篇
  国内免费   2篇
耳鼻咽喉   19篇
儿科学   41篇
妇产科学   26篇
基础医学   85篇
口腔科学   75篇
临床医学   65篇
内科学   238篇
皮肤病学   4篇
神经病学   41篇
特种医学   46篇
外科学   176篇
综合类   10篇
一般理论   2篇
预防医学   35篇
眼科学   40篇
药学   37篇
中国医学   2篇
肿瘤学   72篇
  2023年   14篇
  2022年   24篇
  2021年   46篇
  2020年   26篇
  2019年   41篇
  2018年   35篇
  2017年   35篇
  2016年   37篇
  2015年   38篇
  2014年   52篇
  2013年   67篇
  2012年   75篇
  2011年   71篇
  2010年   42篇
  2009年   36篇
  2008年   47篇
  2007年   70篇
  2006年   68篇
  2005年   56篇
  2004年   40篇
  2003年   32篇
  2002年   13篇
  2001年   4篇
  2000年   6篇
  1999年   11篇
  1998年   2篇
  1997年   3篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   6篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   4篇
排序方式: 共有1014条查询结果,搜索用时 19 毫秒
71.
Rationale Nitric oxide (NO) is implicated in both acute effects of addictive drugs and development of dependence to them. We investigated the role of NO in nicotine-induced locomotor sensitization.Objectives The effects of N-nitro-l-arginine methyl ester (l-NAME), a NO synthase inhibitor, and a combination of a NO precursor l-arginine and l-NAME on nicotine-induced locomotor sensitization were investigated in Swiss Webster mice.Methods Sensitization to psychomotor stimulating effect of nicotine was rendered by seven injections of nicotine (1 mg/kg) on every other day. To investigate their effect on the development of sensitization to nicotine, l-NAME (15–60 mg/kg) and l-arginine (1 g/kg) were given before nicotine administration during the first seven sessions. To investigate the effect of these compounds on the expression of nicotine sensitization, after a 4-day drug-free period another group of mice received a challenge injection of nicotine on day 18.Results Nicotine (1 mg/kg) produced a robust locomotor sensitization in mice. The doses of 30 mg/kg and 60 mg/kg of l-NAME blocked the development of sensitization to nicotine; and, l-arginine (1 g/kg) pretreatment reversed this effect of l-NAME. Likewise, the doses of 30 mg/kg and 60 mg/kg of l-NAME inhibited the expression of sensitization to nicotine on day 18; and, l-arginine (1 g/kg) pretreatment reversed this inhibitory effect of l-NAME.Conclusions Our results suggest that NO is implicated in the development and expression of nicotine-induced locomotor sensitization in mice.  相似文献   
72.
73.
Miliary tuberculosis is caused by the hematogenous spread of Mycobacterium tuberculosis and consists of 1.5% of all tuberculosis cases. It is seen mostly in infants because of the immature immune system, and central nervous system CNS involvement is not rare. Tuberculomas are rarely seen in the localized form of CNS tuberculosis, and only 4% are localized in the brain stem. We report a 4.5-month-old infant who deteriorated during follow-up with the diagnosis of cytomegalovirus pneumonia, and afterwards received the diagnosis of miliary tuberculosis. Although the baby had no neurologic abnormality and cerebrospinal fluid findings were normal, cranial MRI revealed contrast enhanced nodular lesions in pons, cerebellum, and right parietal region. The case is presented to intensify the importance of CNS investigation even if the patient with miliary tuberculosis has no neurologic finding.  相似文献   
74.
Although hyaluronic acid-carboxymethylcellulose (HA-CMC) membrane has the advantage of preventing intraabdominal adhesions, it has theoretical risk of negative effects on the healing of intestinal suture lines by forming a barrier between the suture lines and neighboring serosal surfaces. This study evaluated the effect of HA-CMC on bowel anastomoses, scar healing, and intraabdominal adhesion formation. Two groups of 10 male Sprague-Dawley rats were examined. In the first group, laparotomy was performed with a median incision. Colotomy on the cecum and a single-layer repair of the bowel wall was performed. HA-CMC membrane was placed on the cecal suture line and under the laparotomy incision before abdominal closure. The second group had the same procedure but no HA-CMC membrane was placed. The animals were killed on postoperative day 14. Intraabdominal adhesions, laparotomy suture line endurance, bursting pressure of the repaired cecal wall, and tissue hydroxyproline levels were determined. The repaired cecal wall was also examined histopathologically. The statistical analyses revealed that HA-CMC prevented intraabdominal adhesions significantly. No negative effects of this material on the healing of the bowel and laparotomy suture lines were observed. HA-CMC appears to be a safe material to prevent intraabdominal adhesions, without negative effects on the healing of abdominal incisions and bowel suture lines.  相似文献   
75.
Comparison of Prosthetic Materials in Incisional Hernia Repair   总被引:5,自引:0,他引:5  
Purpose Incisional hernias are not uncommon after abdominal surgery, but their repair is associated with a high risk of complications, including adhesions and recurrence. Many different types of meshes and adhesion barriers have been developed in an attempt to overcome these problems, some of which we have assessed in a rat model.Methods We made a full-thickness 1.5 × 2.5-cm abdominal wall defect in 30 Sprague-Dawley rats, which were divided into three groups according to the materials used for repair: 2 × 3-cm polypropylene mesh (group 1); expanded polytetrafluoroethylene (PTFE) with double-layer polypropylene mesh (group 2); or polypropylene mesh with oxidized cellulose adhesion barriers (group 3). We assessed adhesion formation, tensile strength, and histopathologic findings.Results The mean adhesion scores were 3.3, 1.3, and 0.7, in groups 1, 2, and 3, respectively (P < 0.001). The area involved by adhesions was significantly greater in group 1 than in groups 2 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 2 and 3 (P < 0.05). The tensile strength in group 2 was less than that in groups 1 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 1 and 3 (P > 0.05).Conclusion Although there was less adhesion formation with PTFE and oxidized cellulose, PTFE not only impaired the tensile strength, but also induced fibrosis and inflammation. An oxidized cellulose adhesion barrier can be safely used in incisional hernia repair to prevent intra-abdominal adhesions.  相似文献   
76.
This article describes a technique for fabricating a dowel and core for a tooth with an overflared root canal. The technique involves supporting a glass fiber-reinforced prefabricated dowel with chopped silanated glass fibers.  相似文献   
77.
The high co-occurrence of an abdominal wall hernia (AWH) and stress urinary incontinence (SUI) suggests that there is a common factor in the etiopathogenesis of these disorders in these patients.  相似文献   
78.
OBJECTIVE: The analgesic effect of bupivacaine/fentanyl with epinephrine given interpleurally after thoracotomy was investigated in a randomized placebo and intravenous controlled study. DESIGN: Prospective clinical study. SETTING: University teaching hospital. PARTICIPANTS: Sixty American Society of Anesthesiologists physical status II and III patients scheduled for posterolateral thoracotomy with general anesthesia. INTERVENTIONS: Patients were randomly divided into 4 groups to receive either 0.5% bupivacaine/1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine (n = 15, group IPBF), 0.5 % bupivacaine with 5 microg/mL of epinephrine (n = 15, group IPB), or saline (n = 15, group IPS) in a total volume of 15 to 20 mL in 60 seconds by an interpleural catheter placed at the end of surgery by direct vision. The same volume of bupivacaine 0.25% and 1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine to group IPBF, bupivacaine 0.25% with 5 microg/mL of epinephrine to group IPB or saline to group IPS was injected through the interpleural catheter every 6 hours for 48 hours postoperatively. Intravenous fentanyl (n = 15, group IVF) and interpleural saline groups received 1.5 microg/kg of fentanyl intravenously at the first complaint of pain. All patients also received patient-controlled analgesia (PCA) with fentanyl for 48 hours postoperatively. Metamizol sodium was used as a rescue analgesic. MEASUREMENTS and MAIN RESULTS: Adequacy of pain relief was evaluated with the "Prince Henry Pain Scale" and visual analog pain scale. Fentanyl consumption via PCA and complications were evaluated for 48 hours. Visual analog scale scores were significantly higher in the interpleural saline group at 4 and 12 hours (6.6 +/- 1.2 and 5.0 +/- 2.1, respectively) postoperatively. Significantly more patients in the IPBF group had lower pain scores during coughing and deep breathing. Fentanyl consumption via PCA device was significantly higher in the intravenous fentanyl group (1,069 +/- 96.9 microg) than the interpleural groups (577.3 +/- 72.2 microg, 651.1 +/- 61.9 microg, and 601.0 +/- 22.6 microg in IPBF, IPB, and IPS groups, respectively). CONCLUSION: It is concluded that total fentanyl consumption via PCA decreased in all interpleural groups, but pain during coughing and deep breathing was significantly reduced in only the interpleural bupivacaine/fentanyl with epinephrine group.  相似文献   
79.
80.
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