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   148篇
  免费   11篇
耳鼻咽喉   2篇
儿科学   4篇
基础医学   13篇
口腔科学   5篇
临床医学   14篇
内科学   36篇
皮肤病学   10篇
神经病学   4篇
特种医学   30篇
外科学   15篇
综合类   8篇
预防医学   5篇
眼科学   2篇
药学   7篇
肿瘤学   4篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   4篇
  2016年   7篇
  2015年   4篇
  2014年   2篇
  2013年   2篇
  2012年   4篇
  2011年   1篇
  2010年   9篇
  2009年   9篇
  2008年   2篇
  2007年   9篇
  2006年   2篇
  2005年   3篇
  2004年   6篇
  2003年   3篇
  2002年   1篇
  2000年   2篇
  1999年   1篇
  1998年   6篇
  1997年   5篇
  1996年   6篇
  1995年   1篇
  1994年   4篇
  1993年   4篇
  1992年   3篇
  1990年   2篇
  1989年   4篇
  1988年   5篇
  1987年   3篇
  1986年   3篇
  1985年   1篇
  1984年   3篇
  1983年   4篇
  1982年   5篇
  1980年   2篇
  1978年   3篇
  1977年   2篇
  1976年   8篇
  1975年   2篇
排序方式: 共有159条查询结果,搜索用时 15 毫秒
31.
Thein  SL; Hesketh  C; Brown  JM; Anstey  AV; Weatherall  DJ 《Blood》1989,73(4):924-930
Two families, one of Anglo-Saxon-Dutch descent, and the other, West Indian black, have an atypical beta thalassemia characterized by an unusually high level of Hb A2 in the heterozygous state. Restriction endonuclease mapping showed a deletion of about 1.35 kilobase (kb) in the 5' region of the beta globin gene. Direct sequencing of a specific region of genomic DNA amplified by a new modification of the polymerase chain reaction defined the deletion to be 1,393 base pairs (bp) and to be the same in both families. The deletion extends from 485 bp 5' to the mRNA CAP site to the middle of the second intervening sequence. This deletion, together with three others previously described that remove the 5' end of the beta gene but leave the delta gene intact, are all associated with unusually high levels of Hb A2 in the heterozygous state.  相似文献   
32.
Headache in lacunar stroke   总被引:1,自引:0,他引:1  
The presence of headache within a 72-h interval of stroke onset was investigated in a cohort of 145 lacunar infarcts. Fourteen (10%) experienced diffuse or bilateral headache. Hypertension was less frequent (43 vs 76%; 95% CI: 6 to 60%) and of shorter duration (2.4 vs 7.8 years; t = 2.29; p = 0.02) among patients with headache. Leukoaraiosis was less frequent (40% vs 71%; 95% CI: −57 to −7%) and severe (7 vs 24%; 95% CI: −33 to −2%) in patients with headache. Age, sex, stroke risk factors, type of lacunar stroke, mode of onset, stroke severity, ultrasound and other CT findings were similar in patients with and without headache. No differences in the sixth month neurological or functional outcome were detected between lacunar patients with and without headache. Headache in lacunar stroke cannot be predicted by the clinical characteristics of the stroke and is not due to coexisting cardiembolism, intra or extracranial disease. Hypertensive small-vessel disease is less common and severe in lacunar strokes with associated headache.  相似文献   
33.
AV Osorio  US Alon 《Pediatrics》1997,100(4):675-681
OBJECTIVES: 1) To evaluate the relationships between urinary sodium (UNa), potassium (UK), and calcium (UCa) excretion in the pediatric population; and 2) to determine the effect of increasing potassium intake in patients with idiopathic hypercalciuria and investigate whether this intervention can be offered as another mode of therapy in this patient population. DESIGN: Prospectively, we determined UNa, UK, UCa, and creatinine (Cr) concentrations in randomly collected urine samples from children on initial evaluation for urinary frequency, dysuria, hematuria, enuresis, or kidney stones to identify children with hypercalciuria. SETTING: The outpatient renal clinic of an academic hospital. PARTICIPANTS: Twenty-three black children (13 girls and 10 boys) and 77 white children (44 girls and 33 boys) 3.92 to 16.67 years of age. INTERVENTIONS: Eleven children with hypercalciuria were given potassium supplementation or placed on a high-potassium diet for at least 2 weeks. OUTCOME MEASURES: UNa to UK, UNa to Cr, UK to Cr, and UCa to Cr ratios were calculated from measured levels of urinary minerals. These were repeated in 11 hypercalciuric patients after 2 weeks of increased potassium intake. RESULTS: A total of 100 urine samples were analyzed. The UCa/Cr ratio in blacks 0.04 +/- 0.06 (mean +/- standard deviation) was significantly lower than in whites 0.16 +/- 0.12. There were 21 hypercalciuric white children versus only 1 black child. Linear regression analysis revealed a positive direct correlation between UNa/Cr and UCa/Cr in all 100 subjects and in whites alone but not in blacks. An inverse relationship existed between UK/Cr and UCa/Cr in all subjects and in whites and showed a strong trend in blacks. A marked direct relationship was found between UNa/K and UCa/Cr in all subjects (r = .43) as well as in whites (r = .59) and blacks (r = .49). One black child and 10 white hypercalciuric children were treated with "extra" K for at least 2 weeks. The UNa/K decreased from 4.73 +/- 2.28 to 1.98 +/- 1.09, and the UCa/Cr decreased from 0. 31 +/- 0.10 to 0.14 +/- 0.07, with resolution or improvement of the patients' symptoms. CONCLUSIONS: In our patient population with urinary symptoms, the UCa/Cr ratio in black children is lower and hypercalciuria less common than in white children. In both white and black populations, the UNa/K ratio had the strongest association with the UCa/Cr ratio, indicating an opposing role of UNa and UK on the UCa/Cr ratio. Increased potassium intake was found to be beneficial for hypercalciuric children by decreasing the UNa/K ratio and, consequently, the UCa/Cr ratio.  相似文献   
34.
Complex space environments, including microgravity and radiation, affect the body''s central nervous system, endocrine system, circulatory system, and reproductive system. Radiation-induced aberration in the neuronal integrity and cognitive functions are particularly well known. Moreover, ionizing radiation is a likely contributor to alterations in the microbiome. However, there is a lacuna between radiation-induced memory impairment and gut microbiota. The present study was aimed at investigating the effects of simulated space-type radiation on learning and memory ability and gut microbiota in mice. Adult mice were irradiated by 60Co-γ rays at 4 Gy to simulate spatial radiation; behavioral experiments, pathological experiments, and transmission electron microscopy all showed that radiation impaired learning and memory ability and hippocampal neurons in mice, which was similar to the cognitive impairment in neurodegenerative diseases. In addition, we observed that radiation destroyed the colonic structure of mice, decreased the expression of tight junction proteins, and increased inflammation levels, which might lead to dysregulation of the intestinal microbiota. We found a correlation between the brain and colon in the changes in neurotransmitters associated with learning and memory. The 16S rRNA results showed that the bacteria associated with these neurotransmitters were also changed at the genus level and were significantly correlated. These results indicate that radiation-induced memory and cognitive impairment can be linked to gut microbiota through neurotransmitters.

Exposure to 60Co-γ ray impacts learning and memory ability as well as the cell morphology and neurotransmitters in hippocampus, even disrupts the bacterial community in colon.  相似文献   
35.
36.
Labial adhesions are usually seen in early childhood or in the postmenopausal years, but this clinical entity is rarely seen in the reproductive years. We report a case of labial adhesion with acute urinary retention secondary to Bartholin's abscess in a reproductive‐aged woman with normal menstrual periods. We emphasize the possible occurrence of labial adhesion following Bartholin's abscess in the reproductive years with normal estrogen levels.  相似文献   
37.
Myo-inositol transport in the central nervous system   总被引:18,自引:0,他引:18  
  相似文献   
38.
A prospective, longitudinal two-year study to determine the epidemiology of persistent ( 14 days'duration) diarrhea in rural children of Guatemala was undertaken. Three-hundred and twenty-one children aged 0-35 months were kept under surveillance by twice-a-week home visits. The overall incidence of diarrhea was 0.147 per child-week; the incidence of persistent diarrhea was 0.014 per child-week. The peak of persistent diarrhea was observed in infants below six months of age, with a continuous decline thereafter. This trend in incidence of persistent diarrhea was associated with a higher proportion (16%) of illnesses persisting for more than 13 days in children younger than six months of age as compared to children 30-35 months old (4%). Males had more diarrhea (0.156 per child-week) than females (0.139 per child week). Among children above 18 months of age, the proportion of episodes that lasted for more than 13 days was lower in females than in males.  相似文献   
39.
40.

Background

While the basic ethical issues regarding consent may be universal to all countries, the consent procedures required by international review boards which include detailed scientific and legal information, may not be optimal when administered within certain populations. The time and the technicalities of the process itself intimidate individuals in societies where literacy and awareness about medical and legal rights is low.

Methods

In this study, we examined pregnant women's understanding of group education and counseling (GEC) about HIV/AIDS provided within an antenatal clinic in Maharashtra, India. We then enhanced the GEC process with the use of culturally appropriate visual aids and assessed the subsequent changes in women's understanding of informed consent issues.

Results

We found the use of visual aids during group counseling sessions increased women's overall understanding of key issues regarding informed consent from 38% to 72%. Moreover, if these same visuals were reinforced during individual counseling, improvements in women's overall comprehension rose to 96%.

Conclusions

This study demonstrates that complex constructs such as informed consent can be conveyed in populations with little education and within busy government hospital settings, and that the standard model may not be sufficient to ensure true informed consent.  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