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   2013篇
  免费   97篇
  国内免费   6篇
耳鼻咽喉   5篇
儿科学   164篇
妇产科学   23篇
基础医学   217篇
口腔科学   38篇
临床医学   218篇
内科学   375篇
皮肤病学   36篇
神经病学   107篇
特种医学   269篇
外科学   178篇
综合类   19篇
一般理论   2篇
预防医学   96篇
眼科学   13篇
药学   174篇
中国医学   1篇
肿瘤学   181篇
  2023年   9篇
  2022年   9篇
  2021年   18篇
  2020年   13篇
  2019年   12篇
  2018年   26篇
  2017年   19篇
  2016年   18篇
  2015年   24篇
  2014年   49篇
  2013年   43篇
  2012年   72篇
  2011年   77篇
  2010年   67篇
  2009年   61篇
  2008年   78篇
  2007年   64篇
  2006年   71篇
  2005年   58篇
  2004年   50篇
  2003年   69篇
  2002年   47篇
  2001年   37篇
  2000年   48篇
  1999年   45篇
  1998年   63篇
  1997年   72篇
  1996年   72篇
  1995年   48篇
  1994年   60篇
  1993年   58篇
  1992年   39篇
  1991年   29篇
  1990年   33篇
  1989年   54篇
  1988年   60篇
  1987年   58篇
  1986年   42篇
  1985年   51篇
  1984年   19篇
  1983年   36篇
  1982年   25篇
  1981年   26篇
  1980年   25篇
  1979年   11篇
  1978年   11篇
  1977年   20篇
  1976年   12篇
  1975年   24篇
  1970年   7篇
排序方式: 共有2116条查询结果,搜索用时 218 毫秒
171.
172.
Several epidemiological studies described poor asthma control in children. However, the diagnosis of childhood asthma in these studies is uncertain, and asthma control in children of an outpatient clinic population during treatment by a paediatrician is unknown. (1) to investigate the hypothesis that asthma control in a paediatric outpatient clinic population is better than epidemiological surveys suggest; (2) to find possible explanations for suboptimal asthma control. Asthmatic children aged 6–16 years, known for at least 6 months by a paediatrician at the outpatient clinic, were selected. During a normal visit, both the responsible physicians and parent/children completed a standardised questionnaire about asthma symptoms, limitation of daily activities, treatment, asthma attacks and emergency visits. Overall, excellent asthma control of 8.0% in this study was not significantly better than of 5.8% in the European AIR study (Chi‐square, p = 0.24). Separate GINA goals like minimal chronic symptoms and no limitation of activities were better met in our study. Good to excellent controlled asthma was perceived by most children/parents (83%), but was less frequently indicated by the paediatrician (73%), or by objective criteria of control (45%) (chi‐square, p = 0.0001). The agreement between patient‐perceived and doctor assessed control was low, but improved in poorly controlled children. Patients were not able to perceive the difference between ‘excellent asthma control’ and ‘good control’ (p = 0.881).Too little children with uncontrolled disease got step‐up of their asthma treatment. Although separate GINA goals like ‘minimal chronic symptoms’ and ‘no limitation of activities’ were significantly better in our study, overall, asthma control in this outpatient clinic population, treated by a paediatrician, was not significantly better than in the European AIR study. Poorly controlled disease was related to several aspects of asthma management, which are potentially accessible for improvements.  相似文献   
173.
BACKGROUND: Cardiac tamponade is a rare complication after implantation of dual chamber pacemaker or defibrillator systems. Its pathophysiology and optimal management are not currently well established. METHODS: Three cases of cardiac tamponade following successful implantation of transvenous dual chamber pacemakers with active-fixation atrial leads were identified. RESULTS: All three patients with post-implant cardiac tamponade were suspected to have the same etiology of bleeding into the pericardial space. This was due to protrusion of the helix of the active-fixation atrial pacing lead through the atrial wall with subsequent abrasion of visceral pericardial layer and bleeding from the atrium through the perforation. In two patients, the perforation sites were visualized and repaired during open thoracotomy in the operating room. The third patient underwent lead repositioning under fluoroscopic guidance in the electrophysiology laboratory. CONCLUSION: Based on the reviewed cases, we describe the pathophysiology of, and recommend a safe conservative algorithm for, the management of cardiac tamponade after successful transvenous lead implantation. Percutaneous pericardiocentesis with placement of the pericardial drain followed by lead repositioning under fluoroscopic guidance with surgical backup appears to be safe and effective.  相似文献   
174.
Blood transfusion and postoperative infection in orthopedic patients   总被引:9,自引:0,他引:9  
Adverse effects of the transfusion of homologous blood on tumor recurrence and resistance to bacterial infection have been reported previously, but the findings are inconclusive. A retrospective review of patients undergoing orthopedic surgery was conducted, and the rate of the postoperative infectious complications was compared among those receiving homologous blood, autologous blood, both types, or no transfusion support. An overall postoperative infection rate of 6.1 percent was observed: 6.9 percent among persons receiving homologous blood, 5.0 percent among those receiving autologous blood, 11.9 percent among those receiving both homologous and autologous blood, and 4.9 percent among those not receiving transfusions (p = 0.37). Among patients receiving homologous blood, a subset of 15 patients received homologous whole blood and had an infection rate of 20 percent. Significant predictors of postoperative infection included increasing age, spinal surgery, high admission hematocrit, and greater time in surgery. Of factors relating to transfusion, only the use of homologous whole blood was a significant predictor of postoperative infection, which suggests a detrimental effect of homologous plasma. It can be concluded that, in this group of patients undergoing relatively nontraumatic surgery, several variables that are not related to transfusion, as well as the use of homologous whole blood, were significant predictors of postoperative infection.  相似文献   
175.
The presence of heterophilic antibodies in the serum of a small subpopulation of individuals continues to cause false results for modern-day immunoassays. In order to determine the frequency of heterophilic antibody (HA)-related false positives within our population of positive cardiac troponin I (cTnI) patients, we assayed 200 samples using the original in-house cTnI assay (Abbott AxSYM) and the Bayer ACS:180 cTnI, which we had previously observed to be more effective at blocking HA interference. Four samples were identified as false positives based on discordant results between the two assays, as well as the correction of the false positives by treatment of the samples with heterophilic antibody blocking reagent (HBR). An 'enhanced' version of the AxSYM cTnI reagent was designed to greatly reduce or eliminate HA interference, and has now replaced the original reagents. The present study shows that the enhanced reagent significantly reduced or eliminated much of the HA interference. Comparative studies between the enhanced cTnI reagent and the original Abbott AxSYM cTnI reagent showed excellent correlation and equivalent diagnostic concordance, when HA samples were excluded from the analysis.  相似文献   
176.
This multicentre, double-blind, randomized, placebo-controlled, parallel study was designed to evaluate the efficacy of combined oral lysine acetylsalicylate and metoclopramide (LAS-MCP) in the acute treatment of migraine attacks. A total of 266 patients, 18–65 years old, with two to six attacks of migraine with or without aura (IHS criteria) per month were included. The patients had to treat two migraine attacks with LAS-MCP (1620 mg lysine acetylsalicylate-the equivalent of 900 mg aspirin- combined with 10 mg metoclopramide) or placebo. The main outcome measure was headache relief (reduction in headache severity from grade 3 or 2-severe or moderate-to grade 1 or 0-mild or none) 2 h after treatment. LAS-MCP was superior to placebo for headache relief (56% vs 28%) and for the following secondary outcome measures: complete headache relief (18% vs 7%; p < 0.001), nausea (28% vs 44%; p < 0.001), vomiting (3% vs 11%; p = 0.001), use of rescue medication (47% vs 68%; p < 0.001), global efficacy judged as good or excellent (32% vs 14%; p < 0.001). The tolerability was considered as good in 94% of treated attacks in both groups. Combined oral lysine acetylsalicylate and metoclopramide is an effective and well-tolerated acute treatment of migraine attacks.  相似文献   
177.
JE Kiss  ; D Berman  ; D Van  Thiel 《Transfusion》1998,38(4):327-331
BACKGROUND: Patients who present with fulminant hepatic failure due to Wilson's disease may develop hemolytic anemia and renal insufficiency. In this entity, acute hepatocellular necrosis triggers the release of copper ions into the circulation, which leads to toxic effects on red cell metabolic pathways and hemolysis. STUDY DESIGN AND METHODS: The utility of therapeutic plasma exchange to rapidly remove copper and reduce toxic serum copper levels was studied in two patients with fulminant Wilson's disease. RESULTS: Intensive plasma exchange using fresh-frozen plasma replacement removed substantial amounts of copper from the hypercupremic patients, resulting in a rapid reduction in serum copper levels and decreased hemolysis. The net copper removal was proportional to the serum level, ranging from 7,000 to 11,800 micrograms per procedure in one patient and from 3,700 to 6,800 micrograms in the other. CONCLUSION: Plasma exchange allows a rapid reduction in elevated serum copper levels in patients with fulminant Wilson's disease. This leads to an amelioration of hemolytic anemia and provides clinical stabilization until liver transplantation can be performed.  相似文献   
178.
Growth factors have been identified as the primary cause of osteoinduction in bone healing. Transforming growth factor beta (TGF- beta) has been shown to promote bone formation and is present in bone in high quantities. The aims of the present study were to isolate TGF- beta from human bone, demonstrate its biologic activity, and analyze the effects of conventional sterilization techniques on activity. Bone, obtained from femoral heads of five patients (mean age, 70 years) was ground, demineralized, and freeze-dried, and samples from each patient were divided into three groups: no treatment, sterilization with 1.60 to 1.94 Mrad of 60Co irradiation, and sterilization with ethylene oxide (ETO). Carrier-free recombinant TGF-beta control was also treated and was totally inactivated by ETO but not by irradiation (p < 0.01). TGF- beta activity in demineralized bone was not significantly diminished (p > 0.1) by either sterilization procedure, and substantial amounts of active TGF-beta were recovered in all bone samples: 1.04 +/− 0.77 ng per mg of protein in irradiated samples, 0.67 +/− 0.26 ng per mg in ETO- treated samples, and 1.04 +/− 0.33 in untreated samples, respectively (mean +/− SD). Although a recent report demonstrated that the osteoinductive activity of bone morphogenetic protein in bone powder is diminished considerably by ETO and by 2.5 Mrad of irradiation sterilization of bone powder, these data demonstrate that TGF-beta activity, with its osteoinductive properties, was not destroyed in more coarsely ground, demineralized bone by ETO or by lower doses of irradiation. These findings support the use of human bone allografts in clinical instances involving impaired bone formation.  相似文献   
179.
目的:观察碱性成纤维细胞生长因子对大鼠脑出血后出血灶周围脑组织和出血侧海马bax、bcl-2基因表达的影响,探讨神经营养因子对神经细胞调亡的调控。方法:实验于2006-01/10在广西医科大学医学科学实验中心完成。①取成年清洁级Wistar大鼠72只,雌雄各半,体质量250g左右。②采用脑内囊注射胶原酶建立大鼠脑出血模型,动物于苏醒后按Bederson法进行神经病学评分,评分>3分后入选本实验,入选72只大鼠随机抽签法分为3组,每组24只。碱性成纤维细胞生长因子组按8μg/kg剂量肌肉注射,1次/d;生理盐水组肌肉注射等剂量的生理盐水,1次/d;模型组不作任何干预。③每组分别于干预后1,3,7d随机抽取8只大鼠,麻醉状态下取出血灶周围脑组织和出血侧海马,采用半定量反转录-聚合酶链反应检测调亡调控基因bax mRNA,bcl-2mRNA的表达。结果:在建立脑出血模型中共5只大鼠死亡,随后对死亡动物进行解剖,发现脑内血肿量过大,致脑疝形成而导致死亡,后随机补充动物。72只大鼠进入结果分析。①血肿周围脑组织bax mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组血肿周围脑组织bax mRNA表达比生理盐水组明显减少(3d:0.54±0.19,0.76±0.23,P<0.05;7d:0.45±0.19,0.71±0.16,P<0.01)。②血肿周围脑组织bcl-2mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组的血肿周围脑组织bcl-2mRNA表达比生理盐水组明显增高(3d:0.68±0.25,0.39±0.19,P<0.05;7d:0.80±0.21,0.48±0.18,P<0.01)。③出血侧海马bax mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bax mRNA表达比生理盐水组均明显减少(3d:0.54±0.18,0.70±0.11;7d:0.43±0.24,0.69±0.18,P均<0.05)。④出血侧海马bcl-2mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bcl-2mRNA表达比生理盐水组均明显增多(3d:0.66±0.11,0.50±0.15;7d:0.72±0.12,0.52±0.22,P均<0.05)。结论:碱性成纤维细胞生长因子能调节凋亡相关基因,提高大鼠脑出血后大脑脑组织和海马bcl-2mRNA的表达,降低bax mRNA的表达。  相似文献   
180.
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