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   456篇
  免费   14篇
  国内免费   29篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   9篇
基础医学   30篇
口腔科学   11篇
临床医学   40篇
内科学   86篇
皮肤病学   16篇
神经病学   12篇
特种医学   56篇
外科学   64篇
综合类   63篇
预防医学   12篇
眼科学   9篇
药学   40篇
肿瘤学   20篇
  2023年   1篇
  2022年   4篇
  2021年   5篇
  2020年   3篇
  2019年   6篇
  2017年   1篇
  2016年   3篇
  2015年   8篇
  2014年   12篇
  2013年   11篇
  2012年   14篇
  2011年   21篇
  2010年   24篇
  2009年   25篇
  2008年   22篇
  2007年   23篇
  2006年   25篇
  2005年   15篇
  2004年   11篇
  2003年   7篇
  2002年   6篇
  2001年   8篇
  2000年   5篇
  1999年   6篇
  1998年   29篇
  1997年   35篇
  1996年   32篇
  1995年   18篇
  1994年   13篇
  1993年   18篇
  1992年   5篇
  1990年   5篇
  1989年   11篇
  1988年   5篇
  1987年   9篇
  1986年   3篇
  1985年   13篇
  1984年   5篇
  1983年   4篇
  1982年   5篇
  1981年   6篇
  1980年   1篇
  1978年   4篇
  1977年   2篇
  1975年   3篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1966年   3篇
  1965年   1篇
排序方式: 共有499条查询结果,搜索用时 31 毫秒
21.
Background Perceived age is important to women and is a primary driver for topical product use and facial cosmetic surgery. Changes in facial features and biophysical skin parameters with chronological age and their associations with perceived age have not been described in Asian populations. Objective To investigate the relationship between biophysical properties of the skin, visual features of skin ageing and perceived facial age in Chinese women. Methods Facial photographs were collected of 250 Chinese women, aged 25–70 years in Shanghai, China. The perceived facial age was determined and related to the chronological age for each participant and to a range of visual assessments of skin appearance and objective biophysical measurements of the skin. The profile of changes in these parameters with age was investigated together with the differences in those parameters for women judged to look younger than their chronological age and those judged to look older than their chronological age. Results Large discrepancies in perceived age (up to 29 years) were found in women of the same chronological age. Each objective skin measure and visual assessment parameter had a stronger correlation with perceived age than with chronological age. The strongest relationships to perceived age were for wrinkles and hyperpigmentation. Skin colour, hydration and trans‐epidermal water loss (TEWL) had weaker associations with perceived age. Women judged to look older than their chronological age had significantly higher scores than those judged to look younger for coarse wrinkles and hyperpigmentation across all age groups. The appearance differences between these groups were evident in composite facial images of the same average chronological age. Conclusions We have identified the skin attributes which differ with perceived age in Chinese women. Perceived age is a better measure of the biological age of facial skin than is chronological age in this population.  相似文献   
22.
23.
Neonatal screening in India poses more organisational and socio-economic rather than medical challenges. Based on the pilot study of 450 cord sera, the plan for screening considered cord TSH<30 μU/ml as normal, 30 to 80 as borderline with recall by letters and >80 as indicative of hypothyroid state, with recall by home visits. Of the 17,240 live births only 12,407 cord sera were collected. Envisaging follow-up difficulties, T4 was assayed in cord sera when TSH was>30 μ U/ml. 2·81% (350) babies needed recall. Only 30% of 302 (2·43%) babies with cord TSG 30 to 80 responded, to recall letters and were normal; availability of both cord TSH and T4 helped in excluding hypothyroidism in majority of non-respondents. Forty-eight (0·38%) newborns had TSH>90 μU/ml; 80% of this group and 100% with TSH> 100 μU/ml were traced by home visits. Hypothyroidism was confirmed in 5/48, biochemically and by thyroid scan. All five hypothyroids had cord TSH>300 μU/ml. The incidence in this nonendemic region of India was 1∶2481. Thus false elevation of cord TSH 30 to 300 μU/ml was noted in 0·34% with a chance of detecting a hypothyroid 1 in 10 when TSH>80 μU/ml. Screening strategies in a developing country must ensure meticulous clerical assistance, co-operation and education of nurses and parents, precise and cost effective technics and facilities for continued surveilance of detected hypothyroids.  相似文献   
24.
背景:阿德福韦双酯(ADV) 是一种有效治疗野生型和耐拉米夫定乙肝病毒(HBV)的核苷酸类药物。在使用核苷酸类药物治疗慢性乙肝时,当治疗时间为 48、96、144周时,耐ADV变异体出现的累积发生率分别为0、 0.8-3%和0-5.9%。目的:研究67例对拉米夫定耐药且接受ADV治疗的慢性乙肝患者耐ADV病毒变异体的表型和基因型特点。方法:HBV DNA含量采用实时定量PCR技术。ADV变异体检测采用基质辅助激光解吸电离/飞行时间质谱为基础的基因分型  相似文献   
25.
26.
27.
I n spite of a great deal of work in the field of plastic surgery of the fallopian tubes, the problem still remains largely unsolved and presents a challenge to the ingenuity of every gynaecologist.  相似文献   
28.
Treatment of allergic bronchopulmonary aspergillosis (ABPA) has remained both problematic as well as controversial. Although the sheet anchor in treatment of ABPA still remains steroids, various workers have tried oral antifungals (fluconazole and itraconazole) with encouraging results. This study evaluates the effect of fluconazole or itraconazole in the treatment of ABPA patients and compares them with the patients who had received palliative therapy other than antifungals. Case records of 44 proven cases of ABPA treated at our referral service hospital during February 1998 to April 2001 were analyzed. In addition to oral and inhaled bronchodilators, 16 patients received fluconazole 150 mg OD and 13 patients itraconazole 200 mg OD for six months. Response to therapy was assessed clinically, radiologically and by spirometry every 3 months. Patients who did not receive antifungals had chronic course characterized by airway obstruction, recurrent pulmonary consolidation and obstructive defect on pulmonary function test (PFT). Patients treated with itraconazole had better control of asthma symptoms, less requirement of reliever inhalers, steroids and lesser exacerbations of asthma during follow-up even after stopping antifungal. Fluconazole group had better control of symptoms but improvement in other parameters was not statistically significant. From this study it was evident that itraconazole improved the symptoms of airway obstruction, pulmonary functions, pulmonary opacities and decreased exacerbations during follow up.Key Words: Allergic bronchopulmonary aspergillosis, Fluconazole, Itraconazole  相似文献   
29.
Accuracy of fetal echocardiography   总被引:6,自引:0,他引:6  
Benacerraf  BR; Pober  BR; Sanders  SP 《Radiology》1987,165(3):847-849
The reliability of prenatal ultrasound (US) for the detection of structural heart defects was investigated in a consecutive population of patients referred for prenatal US. Twenty-eight of 49 fetuses (57%) shown to have one or more heart defects with physical examination or autopsy were found to have congenital heart disease with prenatal US. There were 66 cardiac defects in 49 fetuses, 33 of which were entirely or partly identified (50%). Defects correctly diagnosed included hypoplasia of either ventricle, common atrioventricular canal, tetralogy of Fallot, transposition of the great vessels, and Ebstein anomaly. Defects rarely diagnosed correctly included semilunar valve stenosis, total anomalous pulmonary venous drainage, coarctation of the aorta, pulmonic atresia, atrioseptal defect, and ventricular septal defect. Many types of heart defects can be diagnosed accurately with prenatal US in a general population of patients not at high risk for congenital heart disease. Some lesions, however, were difficult to detect.  相似文献   
30.
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