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   183篇
  免费   7篇
耳鼻咽喉   1篇
儿科学   7篇
妇产科学   12篇
基础医学   7篇
口腔科学   1篇
临床医学   24篇
内科学   38篇
皮肤病学   2篇
神经病学   6篇
特种医学   3篇
外科学   22篇
综合类   5篇
一般理论   1篇
预防医学   32篇
眼科学   4篇
药学   25篇
  2021年   1篇
  2016年   3篇
  2015年   2篇
  2014年   1篇
  2013年   5篇
  2010年   4篇
  2009年   2篇
  2008年   1篇
  2007年   2篇
  2006年   2篇
  2001年   1篇
  2000年   1篇
  1999年   3篇
  1998年   3篇
  1997年   8篇
  1996年   8篇
  1995年   8篇
  1994年   3篇
  1993年   5篇
  1992年   6篇
  1991年   3篇
  1990年   7篇
  1989年   9篇
  1988年   4篇
  1987年   1篇
  1986年   11篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   4篇
  1981年   4篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1975年   1篇
  1971年   1篇
  1968年   3篇
  1963年   2篇
  1960年   1篇
  1959年   3篇
  1958年   12篇
  1957年   6篇
  1956年   4篇
  1955年   7篇
  1954年   14篇
  1949年   6篇
  1948年   5篇
  1947年   4篇
排序方式: 共有190条查询结果,搜索用时 17 毫秒
1.
2.
Objective The effects of a computer-assisted instruction (CAI) tutorial program on learning clinical reasoning skills were compared in undergraduate dietetics students.Design A drill-and-practice program to control for time on task, a tutorial program, and a simulation program, as the test vehicle, were developed. The tutorial and simulation programs presented data on a patient with cardiovascular disease.Setting Subjects were tested in 30 undergraduate dietetics programs.Subjects Participants were 413 undergraduate diet therapy students enrolled in a coordinated program in dietetics (CPD) or a didactic program in dietetics (DPD).Intervention After completion of lectures on cardiovascular disease, subjects were given the drill-and-practice program plus a simulation test (group 1), the tutorial plus a simulation test (group 2), or the simulation test only (group 3).Main outcome measures Scores on the simulation test were compared. Variables included type of CAI, dietetics program, year in school, computer experience, and experience using a medical chart. Mastery of objectives related to lower- and higher-level clinical reasoning skills introduced in the tutorial program was compared.Statistical analysis One-way analysis of variance and Student-Newman Keuls tests were conducted to determine any differences among the three groups. Reliability was determined using the Kuder-Richardson Formula 20.Results The reliability coefficient of the simulation test was 0.93. Group 2 scored higher on the simulation test than group 1 or group 3. As a group, the CPD students scored higher than the DPD students. When CPD and DPD students were divided into the three experimental groups, there was no significant difference between the CPD and DPD student simulation scores. Group 2 mastered all objectives for lower-level reasoning skills and the higher-level decision-making objective better than groups 1 and 3.Applications/conclusions A computer tutorial program enhanced clinical reasoning skills in undergraduate dietetics students. This type of program could be used to supplement many topics taught in diet therapy and provide DPD students with experiential learning before their clinical intern practicums. J Am Diet Assoc. 1995; 95:868–873.  相似文献   
3.
4.
Background: The mechanism of hypergastrinaemia during omeprazole therapy is unclear, but is generally assumed to be entirely a consequence of acid suppression. However, direct stimulation of G cells by omeprazole could also be a factor. In order to further investigate the mechanism of omeprazole-induced hypergastrinaemia, we have studied the effects of the drug on plasma gastrin in patients with achlorhydria, in whom altered acid secretion cannot play a role. Methods: We estimated fasting and peptone meal stimulated plasma gastrin in nine patients (seven female) with pernicious anaemia and achlorhydria, before and on the final day of 4 weeks’dosing with omeprazole 40 mg daily. Results: Despite the high fasting gastrin concentrations, the peptone meal produced a further elevation in plasma gastrin concentrations, median gastrin concentrations rising from 1500 ng/L (range 225–10875 ng/L) to 3750 ng/L (range 585–15600 ng/L) post-prandially (P = 0.004). The median post-prandial rise in plasma gastrin at this initial visit was 44% (3–260%), and the median time interval until plasma gastrin concentrations returned to fasting levels was 120 min (range 10- > 150 min). There was a significant negative correlation between fasting plasma gastrin concentrations and the percentage increase in plasma gastrin levels in response to meal stimulation (Spearman correlation coefficient -0.79, P= 0.01). Fasting plasma gastrin concentrations were similar pre-omeprazole (median 1950 ng/L, range 240–16500 ng/L) and postomeprazole (median 1500 ng/L, range 315–7650 ng/L). Likewise, peak plasma gastrin concentrations were also similar pre-omeprazole (median 2700 ng/L, range 585–16500 ng/L) and post omeprazole (median 3420 ng/L, range 720–11250 ng/L). Conclusions: (i) The hyperplastic G cell mass in patients with pernicious anaemia can be further stimulated by a peptone meal, which causes a prolonged rise in plasma gastrin concentrations. (ii) There is a negative correlation between fasting plasma gastrin concentrations and the percentage increase in plasma gastrin levels in response to meal stimulation. (iii) Omeprazole has no effect on plasma gastrin in achlorhydric patients, which is consistent with its hypergastrinaemic effect being entirely secondary to acid inhibition.  相似文献   
5.
Omeprazole heals most duodenal ulcers after 4 weeks of treatment but relapse is common. Eradication of Helicobacter pylori is associated with reduced rate of ulcer relapse. This study investigates the effect of omeprazole with antibiotics in H. pylori-associated duodenal ulceration. Forty-three patients with endoscopically proven duodenal ulcer and H. pylori entered this study. Treatment consisted of 20 mg omeprazole daily (four weeks) and seven days (first week) treatment with 400 mg metronidazole t.d.s. and 500 mg tetracycline t.d.s. Four weeks after completing the treatment, 81 % (35143) had a healed duodenal ulcer, and 58% (25/43) had H. pylori eradication. In those who healed, at one year 21 remained H. pylori-negative, 12 had persistent H. pylori infection and 2 had re-infection. The ulcer relapse rate at one year was 26%: of the 9 who relapsed, 6 had persistent infection, 2 were re-infected, and only 1 was H. pylori-negative. This combination therapy of antibiotics with omeprazole successfully eradicates Helicobacter pylori and has a lower ulcer replase than omeprazole alone.  相似文献   
6.
7.
8.
Aim This meta‐analysis provides a systematic review of studies into intellectual and attentional functioning of paediatric brain tumour survivors (PBTS) as assessed by two widely used measures: the Wechsler Intelligence Scale for Children (3rd edition; WISC‐III) and the Conners’ Continuous Performance Test (CPT). Method Studies were located that reported on performance of PBTS (age range 6–16y). Meta‐analytic effect sizes were calculated for Full‐scale IQ, Performance IQ, and Verbal IQ as measured by the WISC‐III, and mean hit reaction time, errors of omission, and errors of commission as measured by the CPT. Exploratory analyses investigated the possible impacts of treatment mode, tumour location, age at diagnosis, and time since diagnosis on intelligence. Results Twenty‐nine studies were included: 22 reported on the WISC‐III in 710 PBTS and seven on CPT results in 372 PBTS. PBTS performed below average (ps<0.001) on Full‐scale IQ (Cohen’s d=?0.79), Performance IQ (d=?0.90), and Verbal IQ (d=?0.54). PBTS committed more errors of omission than the norm (d=0.82, p<0.001); no differences were found for mean hit reaction time and errors of commission. Cranial radiotherapy, chemotherapy, and longer time since diagnosis were associated with lower WISC‐III scores (ps<0.05). Interpretation PBTS have seriously impaired intellectual functioning and attentiveness. Being treated with cranial radiotherapy and/or chemotherapy as well as longer time since diagnosis leads to worse intellectual functioning.  相似文献   
9.
Aim Fetal androgens influence fetal growth as well as postnatal neurocognitive ability. However, to our knowledge, no published study has prospectively examined the impact of early‐life androgens on infant brain growth. We report the association between circulating fetal androgen levels, measured from umbilical‐cord blood at birth, and a proxy measure of brain growth: head circumference. Method Participants were 82 unselected female infants from a large representative birth cohort (mean gestational age 39.4wks, SD 1.7). Umbilical‐cord blood was obtained at birth and analysed for androgen concentrations (total testosterone, androstenedione, dehyrdroepiandrosterone, and its sulphated metabolite). Head circumference and two other measures of growth – weight (mean 3311.4g, SD 461.3) and length – were measured within 3 days of birth and again at approximately 1 year of age (mean age 13.1mo, SD 1.1). Results Multivariate linear regressions found an inverse association between levels of free testosterone and growth in head circumference (correlation=?.24), even when adjusting for sociodemographic/obstetric covariates and head size at birth. Growth in weight and length could not be predicted by free testosterone concentration. Interpretation This is the first report of an association between prenatal androgen levels and postnatal growth in head circumference. These findings suggest that early‐life androgens may impact brain development during infancy.  相似文献   
10.
Aim Brain systems supporting higher cognitive and motor control develop in a parallel manner, dependent on functional integrity and maturation of related regions, suggesting neighbouring neural circuitry. Concurrent examination of motor and cognitive control can provide a window into neurological development. However, identification of performance‐based measures that do not correlate with IQ has been a challenge. Method Timed motor performance from the Physical and Neurological Examination of Subtle Signs and IQ were analysed in 136 children aged 6 to 16 (mean age 10y 2.6mo, SD 2y 6.4mo; 98 female, 38 male) attending an outpatient neuropsychology clinic and 136 right‐handed comparison individuals aged 6 to 16 (mean age 10y 3.1mo, SD 2y 6.1mo; 98 female, 38 male). Timed activities – three repetitive movements (toe tapping, hand patting, finger tapping) and three sequenced movements (heel–toe tap, hand pronate/supinate, finger sequencing) each performed on the right and left – were included in exploratory factor analyses. Results Among comparison individuals, factor analysis yielded two factors – repetitive and sequenced movements – with the sequenced factor significantly predictive of Verbal IQ (VIQ) (ΔR2=0.018, p=0.019), but not the repetitive factor (ΔR2=0.004, p=0.39). Factor analysis within the clinical group yielded two similar factors (repetitive and sequenced), both significantly predictive of VIQ, (ΔR2=0.028, p=0.015; ΔR2=0.046, p=0.002 respectively). Interpretation Among typical children, repetitive timed tasks may be independent of IQ; however, sequenced tasks share more variance, implying shared neural substrates. Among neurologically vulnerable populations, however, both sequenced and repetitive movements covary with IQ, suggesting that repetitive speed is more indicative of underlying neurological integrity.  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