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   1050篇
  免费   107篇
  国内免费   11篇
耳鼻咽喉   3篇
儿科学   72篇
妇产科学   15篇
基础医学   131篇
口腔科学   39篇
临床医学   115篇
内科学   257篇
皮肤病学   20篇
神经病学   39篇
特种医学   142篇
外科学   78篇
综合类   60篇
预防医学   38篇
眼科学   39篇
药学   73篇
中国医学   2篇
肿瘤学   45篇
  2023年   6篇
  2022年   9篇
  2021年   24篇
  2020年   16篇
  2019年   17篇
  2018年   28篇
  2017年   15篇
  2016年   28篇
  2015年   30篇
  2014年   38篇
  2013年   64篇
  2012年   33篇
  2011年   39篇
  2010年   53篇
  2009年   61篇
  2008年   36篇
  2007年   52篇
  2006年   33篇
  2005年   40篇
  2004年   36篇
  2003年   31篇
  2002年   20篇
  2001年   15篇
  2000年   7篇
  1999年   10篇
  1998年   42篇
  1997年   47篇
  1996年   46篇
  1995年   40篇
  1994年   23篇
  1993年   33篇
  1992年   7篇
  1991年   10篇
  1990年   7篇
  1989年   22篇
  1988年   16篇
  1987年   10篇
  1986年   16篇
  1985年   16篇
  1984年   10篇
  1983年   12篇
  1982年   8篇
  1981年   15篇
  1980年   8篇
  1979年   5篇
  1978年   4篇
  1977年   8篇
  1976年   9篇
  1970年   3篇
  1969年   2篇
排序方式: 共有1168条查询结果,搜索用时 15 毫秒
61.
We evaluated the association of body mass index (BMI) with migraine and migraine specifics in a cross-sectional study of 63 467 women aged ≥ 45 years, of whom 12 613 (19.9%) reported any history of migraine and 9195 had active migraine. Compared with women without migraine and a BMI < 23 kg/m2, women with a BMI ≥ 35 kg/m2 had adjusted odds ratios (ORs) (95% confidence intervals) of 1.03 (0.95, 1.12) for any history of migraine. Findings were similar for active migraineurs. Women with a BMI of ≥ 35 kg/m2 had increased risk for low and high migraine frequency, with the highest estimate for women who reported daily migraine. Compared with women with the lowest associated risk (migraine frequency < 6 times/year; BMI between 27.0 and 29.9 kg/m2), women with a BMI ≥ 35 kg/m2 had an OR of daily migraine of 3.11 (1.12, 8.67). Among the women with active migraine, a BMI ≥ 35 kg/m2 was associated with increased risk of phonophobia and photophobia and decreased risk of a unilateral pain characteristic and migraine aura. Our data confirm previous findings that the association between BMI with migraine is limited to migraine frequency and specific migraine features.  相似文献   
62.
63.
64.
Accurate pregnancy dating is vital to obstetric management. However, first trimester fetal charts commonly used in Australia rely on data reported more than three decades ago. This study reports first trimester dating and growth charts for crown‐rump length between 5 and 14 weeks of gestation and biparietal diameter between 9 and 14 weeks of gestation on an Australia population using modern real‐time ultrasound equipment. All consenting eligible women attending a large Sydney clinic for first trimester ultrasound between March 2005 and December 2006 were recruited. Measurements were carried out to Australasian Society for Ultrasound in Medicine standard protocols. Statistical analyses were undertaken using polynomial regression models and thorough diagnostic checks made. Overall 396 eligible women consented to the study, with 268 between 9 and 14 weeks of gestation. The average participant age was 34 years (range 22–45 years), 371 and all yielded valid biometry measurements. Equations, means and 90% reference intervals for crown‐rump length measurements and biparietal diameter measurements were derived using polynomial regression models. Thorough residual and diagnostic checks were made. Once validated by others, we believe they will warrant consideration for use by Australasian Society for Ultrasound in Medicine.  相似文献   
65.
A cross sectional study assessed the bone mineral density (BMD) of 20 young adult patients who received a renal transplantation in childhood. The BMD of the lumbar spine, mainly trabecular bone, and of the total body, mainly cortical bone, were measured and expressed as an SD score. Fourteen patients (70%) had a BMD SD score of the lumbar spine below -1, of whom six patients were below -2. Fifteen patients (75%) had a BMD SD score of the total body below -1, of whom seven patients were below -2, Both trabecular and cortical bone appeared to be involved in the osteopenic process. The cumulative dose of prednisone was inversely correlated to both lumbar spine and total body BMD SD score. In a multiple regression analysis the cumulative dose of prednisone appeared to be the only factor with a significant effect on BMD SD score. Most young adult patients who had received a renal transplantation in childhood had moderate to severe osteopenia. Corticosteroid treatment played a major part in the development of osteopenia in these patients.  相似文献   
66.
AIM:To detect the contents of four active components of Salvia miltiorrhiza in various commercially available danshen crude drugs and preparations.METHODS:Commercially available danshen crude drugs from different sources,as well as danshen pills and intravenous injection preparations containing danshen alone or in combination with other herbs were collected.The composition of these danshen samples was analyzed using HPLC.Specifically,the amounts of magnesium tanshinoate B(MTB),danshensu,isotanshinone IIA,and cryptotanshinone were determined.In some of these samples,the content of MTB was further confirmed by liquid chromatography-tandem mass spectrometer (LC-MS)/MS method.RESULTS:There were great variations in the amount of the four active ingredients in the commercially available danshen crude drugs and drug preparations in this study.The amount of MTB was the highest among the four components measured in the crude drugs.However,the amounts of MTB in all danshen preparations were much lower than those in crude drugs.The 2 lipophilic components,isotanshinone IIA and cryptotanshinone,were very low or not detectable in both injection and oral preparations.CONCLUSION:MTB can be used to standardize the various forms of danshen crude drugs and drug preparations from different sources.In view of the variation in the amounts of MTB and other components,improvement in the production methods of danshen preparations is essential to ensure consistent amount of its active ingredients and reproducible pharmacological actions.  相似文献   
67.
The phonetic inventories of 122 typically developing Cantonese-speaking children, aged from 0;10 to 4;7, were examined in terms of feature distinctions. The applicability of Dinnsen. Chin, Elbert and Powell's implicational feature hierarchy to these data was investigated. Results show that modifications to the hierarchy are necessary for the Cantonese phonetic system. A revised hierarchy for Cantonese is proposed. Differences between this proposal and the original work are discussed. The implicational nature of the proposed hierarchy was also tested on longitudinal data from ten children (aged from 0;10 to 3;5 at the beginning of the study) over a 1 year period. The proposed hierarchy successfully predicted the route of sound change of these inventories. Implications for further research on feature development are discussed.  相似文献   
68.
Obesity in children may cause overt clinical disease in childhood. The complex endocrine and metabolic changes of obesity and insulin resistance in adolescents result in hyperinsulinemia, dyslipidemia, hypertension, steatohepatitis, glucose intolerance, type 2 diabetes, acanthosis nigricans and ovarian hyperandrogenemia, commonly known as polycystic ovarian syndrome (PCOS). Type 2 diabetes and PCOS in adolescents are new endocrine diseases in this age group that require unique approaches to diagnosis and treatment. The direct correlation between duration of disease and control of the disease, and subsequent long term complications of these two diseases, predict serious morbidity in young adult life for the affected adolescents. Pediatricians have an important role in the prevention, diagnosis and treatment of obesity, insulin resistance syndrome, type 2 diabetes and PCOS.  相似文献   
69.
The relationship between homovanillic acid (HVA), vanillylmandelic acid (VMA), and creatinine in the urine of 6 month old babies has been studied and reference ranges in the form of centiles constructed for HVA and VMA against creatinine. Over 10,000 urine samples were collected from babies in four health districts in the north of England. HVA and VMA concentration, either independently or when divided by creatinine concentration, were dependent upon the absolute concentration of creatinine in the sample. After adjustment for creatinine significant differences in the mean concentration of HVA were found between sexes. No such differences were found for VMA. HVA and VMA were also found to be age dependent. Centiles were constructed using a procedure which makes no distributional assumptions about the data. The net effect of utilising these centiles was to increase the predictive value of a positive screening test from 20% to 40% without any increase in the false negative rate.  相似文献   
70.
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