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   248篇
  免费   35篇
耳鼻咽喉   3篇
儿科学   19篇
妇产科学   2篇
基础医学   50篇
口腔科学   10篇
临床医学   21篇
内科学   35篇
皮肤病学   30篇
神经病学   34篇
特种医学   9篇
外科学   24篇
综合类   5篇
一般理论   1篇
预防医学   8篇
药学   28篇
肿瘤学   4篇
  2023年   3篇
  2022年   4篇
  2020年   3篇
  2019年   7篇
  2018年   12篇
  2017年   8篇
  2016年   10篇
  2015年   8篇
  2014年   7篇
  2013年   8篇
  2012年   20篇
  2011年   12篇
  2010年   6篇
  2009年   5篇
  2008年   5篇
  2007年   7篇
  2006年   9篇
  2005年   10篇
  2004年   11篇
  2003年   7篇
  2002年   6篇
  2001年   7篇
  2000年   7篇
  1999年   4篇
  1997年   5篇
  1996年   4篇
  1995年   5篇
  1994年   7篇
  1993年   6篇
  1992年   5篇
  1991年   4篇
  1990年   3篇
  1989年   2篇
  1988年   5篇
  1987年   5篇
  1986年   5篇
  1984年   2篇
  1981年   2篇
  1978年   1篇
  1977年   1篇
  1976年   3篇
  1975年   4篇
  1974年   9篇
  1973年   5篇
  1972年   3篇
  1971年   3篇
  1970年   1篇
  1969年   1篇
  1966年   2篇
  1965年   1篇
排序方式: 共有283条查询结果,搜索用时 18 毫秒
1.
2.
3.
This study examined sociodemographic, behavioral and psychosocial factors associated with BMI, weight perceptions and trying to lose weight among African-American smokers (N=600, M=44.2 years, 70% female). Sixty-eight percent of the sample were overweight or obese (sample BMI M=28.0, SD=6.7). Three separate, simultaneous multivariable regression models were used to determine which factors were associated with BMI, weight perceptions and trying to lose weight. Poorer health, female gender and high-school education or higher were significantly associated with higher BMIs (p<0.05). Being female (OR=5.8, 95% CI=3.6-9.3) and having a higher BMI (OR=0.6, 95% CI=0.5-0.6) was associated with perception of overweight and smoking more cigarettes per day (OR=1.0, 95% CI=1.0-1.1), and perceiving oneself as overweight (OR=14.1, 95% CI=8.2-24.2) was associated with trying to lose weight. Participants somewhat underestimated their BMI in their weight perceptions. Those who perceived themselves as overweight were more likely to be trying to lose weight; therefore, increasing participant awareness of actual BMI status may lead to improved weight-control efforts in African-American smokers. Several expected associations with outcomes were not found, suggesting that BMI and weight constructs are not well-understood in this population.  相似文献   
4.
The combination of spondyloepiphyseal dysplasia, humoral immune deficiency, growth retardation, intellectual deficit and characteristic facial dysmorphism has recently been delineated as a discrete disorder thus far only reported in males. This report describes a fifth individual with co-existent hypogonadotrophic hypogonadism, thereby expanding the phenotype and possibly offering insight into the genetic aetiology of this condition.  相似文献   
5.
6.
ObjectiveTo explore the use of detrended fluctuation analysis (DFA) scaling exponent of the awake electroencephalogram (EEG) as a new alternative biomarker of neurobehavioural impairment and sleepiness in obstructive sleep apnea (OSA).MethodsEight patients with moderate–severe OSA and nine non-OSA controls underwent a 40-h extended wakefulness challenge with resting awake EEG, neurobehavioural performance (driving simulator and psychomotor vigilance task) and subjective sleepiness recorded every 2-h. The DFA scaling exponent and power spectra of the EEG were calculated at each time point and their correlation with sleepiness and performance were quantified.ResultsDFA scaling exponent and power spectra biomarkers significantly correlated with simultaneously tested performance and self-rated sleepiness across the testing period in OSA patients and controls. Baseline (8am) DFA scaling exponent but not power spectra were markers of impaired simulated driving after 24-h extended wakefulness in OSA (r = 0.738, p = 0.037). OSA patients had a higher scaling exponent and delta power during wakefulness than controls.ConclusionsThe DFA scaling exponent of the awake EEG performed as well as conventional power spectra as a marker of impaired performance and sleepiness resulting from sleep loss.SignificanceDFA may potentially identify patients at risk of neurobehavioural impairment and assess treatment effectiveness.  相似文献   
7.
8.
Iso‐α‐acids (IAAs) can be used as markers for the consumption of beer. Postmortem specimens from a range of coronial cases were analyzed for IAAs in order to determine the prevalence of beer consumption and any correlation to blood alcohol concentrations (BAC). A total of 130 cases were included in this study including those where beer was mentioned in the case circumstances, cases where beer was not mentioned specifically but alcohol was detected, and cases where neither beer was mentioned nor a positive BAC was present. Available blood, serum, vitreous humour and urine specimens were analyzed. Of the 50 cases where beer was mentioned, 86% had one or more IAAs detected. In cases that only had a positive BAC (n = 60), 57% of these cases also showed the presence of these beer markers. IAAs were detected in specimens obtained from traumatized, burnt, and decomposed cases with a mention of beer consumption or where BAC was positive in blood. No IAAs were detected in cases where BAC was negative. There was little or no correlation between blood IAA concentrations and BAC. This study demonstrates the possible detection of IAAs as a marker for beer consumption. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
9.
Parathyroid hormone (PTH)-like bioactivity, assayed as adenylate cyclase response in UMR 106-01 osteogenic sarcoma cells, was present in extracts of sheep fetal and maternal parathyroid glands and placenta. Preincubation of extracts with PTH(1-34) antiserum inhibited approximately 40% of the bioactivity in fetal parathyroid extracts, 50% in maternal parathyroid extracts, but only 10% of the bioactivity in the placental extract. Partial purification of placental extracts by chromatography yielded fractions containing PTH-like bioactivity which were similar in behaviour to that of PTH-related protein (PTHrP) from a human lung cancer cell line (BEN). An antiserum against synthetic PTHrP(1-16) partially inhibited the bioactivity of the placental extract and synthetic PTHrP(1-34), but had no effect on the bioactivity of bovine PTH(1-34) or bovine PTH(1-84). The placental PTH-like bioactivity was higher in mid- than in late gestation. Fetal parathyroid glands contained the highest PTH-like bioactivity. Thyroparathyroidectomy of one fetal twin lamb in each of 16 ewes between 110 and 125 days of gestation resulted in decreases of the plasma calcium concentration and reversal of the placental calcium gradient that existed between the ewe and the intact fetus. Perfusion of the placenta of each twin in anaesthetized ewes was carried out sequentially with autologous fetal blood in the absence of the exsanguinated fetus. The plasma calcium concentration in the blood perfusing the placenta of each twin increased, but reached a plateau at a lower concentration in the perfusing blood of thyroparathyroidectomized fetuses than in that of the intact fetuses. Addition of extracts of fetal parathyroid glands or of partially purified PTHrP resulted in further increases in plasma calcium in the autologous blood perfusing the placentae of thyroparathyroidectomized fetuses, but addition of bovine PTH(1-84) or rat PTH(1-34) had no effect. The presence of this PTH-like protein in the fetal parathyroid gland and placenta may contribute to the relative hypercalcaemia of the fetal lamb. This protein, which is similar to PTHrP associated with humoral hypercalcaemia of malignancy, stimulates the placental calcium pump responsible for maintaining a relative fetal hypercalcaemia during gestation.  相似文献   
10.
An unusual case of cardiac tamponade presenting to the emergency department is reported in a patient with sternal wire disruption after a pectus excavatum repair two years previously. The complication, although rare may have potentially life threatening sequelae and therefore consideration of sternal wire disruption in all patients presenting with chest pain after a previous sternotomy should be made.  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