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   1276篇
  免费   97篇
  国内免费   9篇
耳鼻咽喉   18篇
儿科学   77篇
妇产科学   42篇
基础医学   140篇
口腔科学   33篇
临床医学   102篇
内科学   384篇
皮肤病学   30篇
神经病学   91篇
特种医学   62篇
外科学   195篇
综合类   9篇
预防医学   113篇
眼科学   16篇
药学   38篇
肿瘤学   32篇
  2023年   4篇
  2022年   7篇
  2021年   24篇
  2020年   21篇
  2019年   28篇
  2018年   34篇
  2017年   29篇
  2016年   29篇
  2015年   31篇
  2014年   46篇
  2013年   49篇
  2012年   59篇
  2011年   67篇
  2010年   44篇
  2009年   38篇
  2008年   64篇
  2007年   60篇
  2006年   67篇
  2005年   64篇
  2004年   44篇
  2003年   39篇
  2002年   49篇
  2001年   39篇
  2000年   41篇
  1999年   39篇
  1998年   28篇
  1997年   15篇
  1996年   24篇
  1995年   22篇
  1994年   16篇
  1993年   18篇
  1992年   20篇
  1991年   19篇
  1990年   16篇
  1989年   23篇
  1988年   21篇
  1987年   20篇
  1986年   18篇
  1985年   16篇
  1984年   10篇
  1983年   8篇
  1981年   4篇
  1980年   8篇
  1978年   5篇
  1977年   8篇
  1976年   3篇
  1975年   3篇
  1968年   5篇
  1967年   8篇
  1966年   8篇
排序方式: 共有1382条查询结果,搜索用时 0 毫秒
61.
62.
BackgroundThis study aimed to verify the relationship between different Sedation Rating Scales (SRSs) for critical patients on mechanical ventilation and to know the relationship between the SRSs, clinical information and the dose of sedative and analgesia drugs (SAD).Material and methodsA longitudinal, prospective analytic pilot study conducted in a Medical-Surgical Intensive Care Unit of a tertiary hospital from October-December 2006. The sample included patients who required administration of SAP and mechanical ventilation. The following biological parameters and scales were evaluated: patient's demographics, RAMSAY, Sedation Agitation Scale (SAS), Richmond Agitation Sedation Scale (RASS), Motor Activity Assessment Scale (MASS), SAD dose, mean blood pressure, cardiac rate, pupil diameter and respiratory frequency. Spearman coefficient of interrelation was used to compare the relationship between the different scales.ResultsA total of 2.412 measurements were made for each variable: SRS, clinical information and SAD dose in 30 patients with different diseases, 63 % males, age 52 ± 19 years, APACHEII 24 ± 8, SAPSII 44 ± 16, with an ICU mortality UCI 34 %. Median and IQ range of stay in ICU 15.5 and 20 days, of mechanical ventilation 9 and 14 days, of SAD 6 and 5.5 days and of paralyzing drugs (PD) 2 and 5 days, respectively. Interrelation was detected between all the SRSs, with p < 0.0001. The relationship between SAS, RASS and MASS was direct, whereas these were related inversely to RAMSAY. No evidence of interrelation was found between the SRSs, the clinical information and the SAD doses.ConclusionThe RAMSAY scale that has not been validated in ICU patients has a strong interrelation with the other already validated SRSs. SRSs are subjective and do not correlate with the clinical information and the SAD doses, probably due to the sample's small size and heterogeneity.  相似文献   
63.
A model to explain the evolutionary history of animal-bacteria obligatory mutualistic symbiosis is presented. Dispensability of genes and genetic isolation are key factors in the reduction process of these bacterial genomes. Major steps in such genome reductive evolution, leading towards primary endosimbiosis, and the possibility of complementation or replacement by a secondary symbiont are also indicated. Yet, we need to understand what happens at the beginning of the adaptative process towards an obligate mutualistic relationship. For this purpose, we propose to sequence the complete genome of SOPE, the primary endosymbiont of the rice weevil.  相似文献   
64.
BACKGROUND: Tumour necrosis factor-alpha (TNF-alpha) is an important regulator of the chronic inflammation contributing to tumour progression. Infliximab, an anti-TNF-alpha monoclonal antibody was investigated in this trial of patients with advanced cancer. The primary objectives were to determine the safety profile and biological response of infliximab in a cancer population. Clinical response was a secondary objective. PATIENTS AND METHODS: Forty-one patients received infliximab at 5 mg/kg (n = 21) or 10 mg/kg (n = 20) i.v. at 0 and 2 weeks and then every 4 weeks. Post-treatment samples were measured for changes in plasma and serum TNF-alpha, CCL2, IL-6 and C-reactive protein (CRP). RESULTS: Infliximab was well tolerated with no dose-limiting toxic effects. At both doses of infliximab, neutralisation of serum TNF-alpha was observed after 1 h while plasma CCL2, IL-6 and serum CRP were decreased 24 and 48 h following infliximab administration. Seven patients experienced disease stablisation (range 10-50+ weeks). There was no evidence of disease acceleration in any patient. CONCLUSIONS: Infliximab treatment was safe and well tolerated in patients with advanced cancer. There was evidence of biological activity with baseline TNF-alpha and CCL2 being correlated with infliximab response.  相似文献   
65.
We evaluated the response of preterm fetuses to maternal intravenous injection of 400 micrograms of thyrotropin releasing hormone (TRH) between 30 minutes and 5 hours before delivery (n = 12). An additional seven mothers received saline solution and served as control subjects. There were no statistically significant differences in gestational age, birth weight, or Apgar scores between groups. At delivery, concentrations of maternal thyrotropin were elevated in the TRH group compared with the control group (12.0 +/- 1.6 vs 5.6 +/- 0.5 mU/L; p less than 0.005); however, maternal triiodothyronine (T3) values remained unchanged. Significant elevations of fetal thyrotropin and T3 were observed after maternal administration of TRH compared with control subjects (45.8 +/- 7.7 vs 8.4 +/- 0.9 mU/L (p less than 0.002) and 1.3 +/- 0.07 vs 0.7 +/- 0.04 nmol/L or 87 +/- 5 vs 49 +/- 3 ng/dl (p less than 0.001), respectively). Fetal thyroxine (T4) and prolactin values were also elevated after exposure to TRH (135 +/- 5 vs 86 +/- 10 nmol/L or 10.5 +/- 0.4 vs 6.7 +/- 0.8 micrograms/dl (p less than 0.001) and 212 +/- 31 vs 105 +/- 28 micrograms/L (p less than 0.05), respectively). Two hours after birth, a significant increase in T3 but not T4 levels was observed in both groups of infants. These data indicate that fetal exposure to a single dose of TRH via maternal administration of this hormone results in marked stimulation of the preterm fetal pituitary-thyroid axis, as in the fetus at term, and that this treatment does not inhibit the early postnatal surge of T3.  相似文献   
66.
Objective: To ascertain blood lead levels in a sample of preschool children from Fremantle, Western Australia, and to correlate these with possible risk factors.
Methodology The study was a cross-sectional prevalence survey of 120 children from day-care centres and 44 hospital inpatients. Blood lead and ferritin levels were determined and a risk factor questionnaire was completed by parents.
Results Of the 164 children 25.6% had lead levels above the NH&MRC goal (<10μg/dL). Nine of 133 (6.7%) had ferritin levels below 10 μg/L suggesting iron deficiency. Excessive blood lead concentrations as defined by the NH&MRC (>9μg/dL) related to: child's presence during house renovation (OR 3.35, P = 0.007, 95% Cl 1.39-8.81); Aboriginality (OR 6.4, P = 0.008, 95% Cl 1.6-24.9), and, in the 9-24 month age group, inversely to distance between home and a road carrying >7000 vehicles/day (r-0.56, P = 0.009, n = 24).
Conclusions A group of Fremantle children with unacceptably high blood lead levels has been identified. Renovation of older housing and Aboriginality are important risk factors.  相似文献   
67.
68.
Abou-Jaoude ES  Brooks M  Katz DG  Van Meter WS 《Ophthalmology》2002,109(7):1291-6; discussion 1297
PURPOSE: To determine the incidence and complications of spontaneous wound dehiscence after removal of a single continuous penetrating keratoplasty (PK) suture. DESIGN: Retrospective consecutive, noncomparative interventional case series. METHODS: Retrospective review of 324 consecutive continuous suture PKs performed between 1992 and 1999. RESULTS: Sixty-nine (21.3%) of 324 PKs reviewed had the continuous suture removed. The average interval for suture removal after PK was 24.5 +/- 15 months (range, 2.8-63.3 months). Five of the 69 eyes (7.2%) developed spontaneous wound dehiscence without direct eye trauma. In the five eyes that developed wound dehiscence, the continuous suture was removed at 24.6 +/- 10.3 months (range, 14-42 months). Dehiscence occurred at 11.6 +/- 6.5 (range, 3-18) days after suture removal. Significant history associated with wound dehiscence included coughing, yawning, falling without trauma to the eye, and spontaneous wound separation. The reasons for suture removal were astigmatism in four of five (80%) patients and a broken suture in one of the five patients. In four of five (80%) patients, the location of wound dehiscence correlated with the steep axis of corneal keratometry before suture removal. Surgical intervention preserved the presuture removal best-corrected visual acuity in four of the five eyes. No eyes with an intact suture spontaneously dehisced. CONCLUSIONS: The rate of spontaneous wound dehiscence after removal of a continuous suture in our series was 7.2%. All spontaneous dehiscences occurred within 2 weeks after suture removal. Older patients, who had PK for corneal edema with postoperative astigmatism and have been using corticosteroids drops for prolonged periods of time, are at higher risk of wound dehiscence. Patients should be monitored closely during the first 2 weeks after removal of a continuous suture for signs of wound separation, especially when suture removal is performed for astigmatism. Patients should be cautioned about the risk and symptoms of wound dehiscence before suture removal to facilitate early recognition and intervention for preservation of best visual potential.  相似文献   
69.
70.
OBJECTIVES: To investigate whether patients admitted to the postanesthesia recovery unit (PRU) need routine oxygen supplementation in the immediate postoperative period, by measuring changes in arterial oxygen saturation (SpO2) with a pulse oximeter. MATERIAL AND METHODS: Two hundred ninety-nine patients were admitted to the PRU after surgery. All breathed room air after their operations. During transfer to and time in the PRU, SpO2 was recorded. We administered oxygen through a face mask to patients whose SpO2 fell below 94% and to patients whose SpO2 levels fell below baseline, when baseline values were less than 94%. We recorded patient data, physical status (ASA), type of anesthesia, duration of surgery, Aldrete score upon admission to the PRU and SpO2 before and after surgery while the patient breathed room air. RESULTS: General anesthesia was used in 82.3% of the patients and local-regional anesthesia with sedation in 17.7%. PRU stay was 75.6 +/- 92.4 min. Twenty-five percent of the patients were treated with oxygen after surgery and 75% did not require supplemental oxygen. Time until the appearance of desaturation was 3.3 +/- 2.8 min. The coefficient of multiple correlation between postoperative SpO2 while breathing room air (dependent variable) and preoperative SpO2, age and duration of surgery was R = 0.522 (p < 0.001). CONCLUSIONS: Our results are sufficient to demonstrate the validity of pulse oximetry for avoiding indiscriminate oxygen supplementation in patients admitted to the PRU.  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