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   1299130篇
  免费   99975篇
  国内免费   2025篇
耳鼻咽喉   18613篇
儿科学   44870篇
妇产科学   35504篇
基础医学   185002篇
口腔科学   34151篇
临床医学   113456篇
内科学   262384篇
皮肤病学   28280篇
神经病学   102619篇
特种医学   52061篇
外国民族医学   661篇
外科学   199023篇
综合类   27648篇
现状与发展   1篇
一般理论   402篇
预防医学   97632篇
眼科学   28460篇
药学   96204篇
  4篇
中国医学   2450篇
肿瘤学   71705篇
  2018年   13466篇
  2017年   10218篇
  2016年   11146篇
  2015年   12676篇
  2014年   17582篇
  2013年   26991篇
  2012年   37029篇
  2011年   39121篇
  2010年   23365篇
  2009年   22365篇
  2008年   37588篇
  2007年   40302篇
  2006年   40603篇
  2005年   39547篇
  2004年   38671篇
  2003年   37468篇
  2002年   36803篇
  2001年   64378篇
  2000年   66874篇
  1999年   56773篇
  1998年   15364篇
  1997年   13957篇
  1996年   14405篇
  1995年   13680篇
  1994年   12962篇
  1993年   11981篇
  1992年   44857篇
  1991年   43817篇
  1990年   42536篇
  1989年   40382篇
  1988年   37214篇
  1987年   36502篇
  1986年   33876篇
  1985年   32550篇
  1984年   24400篇
  1983年   20475篇
  1982年   11905篇
  1981年   10892篇
  1980年   9699篇
  1979年   21586篇
  1978年   15014篇
  1977年   12716篇
  1976年   11850篇
  1975年   12792篇
  1974年   14852篇
  1973年   14270篇
  1972年   13107篇
  1971年   11873篇
  1970年   11182篇
  1969年   10150篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Case report 506   总被引:1,自引:0,他引:1  
  相似文献   
102.
103.
The sodium, potassium and creatinine contents of three non-consecutive 24-h urine samples collected by 34 selected adult individuals (10 m; 24 f) living in Cork City were determined. The pooled mean 24-h excretion of sodium and potassium in collections adjudged to be complete were 152 mmol and 78 mmol, respectively. There was no significant difference between group average weekday and weekend-day excretion of Na or K, for either males or females. This suggests that weekend 24-h urinary collections, which most subjects find more convenient, are suitable for studies of sodium and potassium intakes of groups. The ratios of intra- to inter-individual variation for 24-h urinary sodium were 1.4 and 2.1 for males and females, respectively. The corresponding ratios for 24-h urinary potassium were 6.6 for males and 4.9 for females. These ratios indicated that there were large individual day-to-day variations in urinary sodium and potassium excretion in this group. It was estimated that a sample size of 35-60 individuals would be required to estimate group mean sodium and potassium intakes by means of single 24-h urine collections.  相似文献   
104.
Vogt-Koyanagi-Harada syndrome and pregnancy   总被引:2,自引:0,他引:2  
Two black women had bilateral anterior and posterior uveitis, nonrhegmatogenous retinal detachments, pleocytosis, headaches, dysacousis, and alopecia. These patients with Vogt-Koyanagi-Harada (VKH) syndrome improved clinically while they were pregnant after the discontinuation of corticosteroid treatment. They developed recurrent symptoms and findings after termination of their pregnancies. We speculate that changes in immunity and humoral constituents during pregnancy account for their remissions. It is important to assess the menstrual history and to avoid pregnancy before initiating steroid treatment for VKH syndrome.  相似文献   
105.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
106.
Keloids     
Keloids are benign fibrous growths that result from an abnormal connective tissue response in certain predisposed individuals. Blacks form keloids more often than whites; however, the reason for this racial difference is not known. Trauma, foreign-body reactions, infections, and endocrine dysfunction have all been proposed as precipitating factors. Keloids are found most commonly on the ear lobes, shoulders, upper back, and midchest. They extend past the area of trauma and once present tend to remain stable. Although sometimes pruritic, painful, or tender, they are usually asymptomatic. Histologically, keloids are characterized by thick collagen bundles, abundant mucinous ground substance, few fibroblasts, and few if any foreign-body reactions. Although there have been many therapeutic modalities, most have had limited success. The most commonly used therapeutic approach is a combination of cryotherapy, intralesional steroid injections, surgical excision, and pressure devices.  相似文献   
107.
108.
The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status.  相似文献   
109.
110.
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