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   729367篇
  免费   50083篇
  国内免费   1401篇
耳鼻咽喉   9576篇
儿科学   23733篇
妇产科学   17885篇
基础医学   113619篇
口腔科学   20523篇
临床医学   65384篇
内科学   140195篇
皮肤病学   16747篇
神经病学   51059篇
特种医学   26683篇
外国民族医学   77篇
外科学   108415篇
综合类   14953篇
现状与发展   2篇
一般理论   162篇
预防医学   52012篇
眼科学   16622篇
药学   55724篇
  3篇
中国医学   2429篇
肿瘤学   45048篇
  2021年   5862篇
  2018年   8267篇
  2017年   6436篇
  2016年   7228篇
  2015年   7946篇
  2014年   10847篇
  2013年   16054篇
  2012年   21591篇
  2011年   22683篇
  2010年   13380篇
  2009年   12573篇
  2008年   21038篇
  2007年   22713篇
  2006年   23011篇
  2005年   21627篇
  2004年   21118篇
  2003年   19935篇
  2002年   19405篇
  2001年   37092篇
  2000年   37609篇
  1999年   31070篇
  1998年   8158篇
  1997年   6856篇
  1996年   7185篇
  1995年   6793篇
  1994年   6242篇
  1993年   5764篇
  1992年   23449篇
  1991年   23337篇
  1990年   22720篇
  1989年   22474篇
  1988年   20424篇
  1987年   19781篇
  1986年   18811篇
  1985年   17645篇
  1984年   12937篇
  1983年   10954篇
  1982年   6050篇
  1979年   11718篇
  1978年   8254篇
  1977年   6991篇
  1976年   6694篇
  1975年   7400篇
  1974年   8622篇
  1973年   8299篇
  1972年   7829篇
  1971年   7297篇
  1970年   7025篇
  1969年   6473篇
  1968年   5935篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture.  相似文献   
102.
The authors suggest additional criteria evidencing inflammations in the gallbladder and colloid stability of the bile: bile acid absorption and cholesterol sedimentation coefficients. Derivation of these coefficients is based on biochemical examination of the bile with measurements of bile acid, cholesterol, and bilirubin concentrations in both portions. The results of examinations of 99 subjects evidence the diagnostic value and specificity of the characteristics, and availability of this method for clinical practice.  相似文献   
103.
A number of children who are admitted for inpatient psychiatric treatment have experienced significant trauma and abuse. It is important to evaluate them for the presence of a DD. The variety, complexity, and subtlety of the symptomatic presentation of childhood MPD makes differential diagnosis difficult, and it is probable that many cases have been missed in the past. Detailed historical information and extensive behavioral observations in a variety of settings can assist in establishing the diagnosis and in delineating areas for therapeutic intervention. Hospitalization may be necessary to conduct an adequate evaluation, develop a therapeutic alliance, safely manage behaviors that are injurious to the child or others, and/or to diffuse potentially volatile family situations. All members of a multidisciplinary inpatient team play important roles in the achievement of successful therapeutic intervention with dissociating children and their families. Skilled family therapy is often an important adjunct to therapeutic interventions focused on the child, particularly when the parent also has MPD. Knowledge of the psychodynamic issues involved in dissociation can be used to develop behavioral interventions that are successful in decreasing the child's need to dissociate, improving his or her overall functioning, and help him or her gain mastery over problematic behaviors.  相似文献   
104.
Genetic factors for the span of apprehension test: a study of normal twins.   总被引:1,自引:0,他引:1  
The Partial Report Span of Apprehension test has been found to detect cognitive deficits in some first degree relatives of schizophrenic patients. To assess the relative contribution of genetic vs. environmental factors on this measure, 19 monozygotic and 14 dizygotic female twin pairs, selected from a normal population, were tested on the Span of Apprehension test and an IQ test. Both Span of Apprehension test performance and IQ score had high heritabilities: 0.65 and 0.71, respectively. The mode of transmission for performance on the Span of Apprehension test appears to operate in a nonadditive manner. A multivariate behavioral-genetic model applied to the Span of Apprehension and IQ measures indicated that slightly less than half of the genetic effects important for the Span of Apprehension test are found in common with the genetic factors important for IQ. The phenotypic correlation between the Span of Apprehension and IQ measures can be attributed entirely to genetic factors. The influence of unique genetic components in the performance of the Span of Apprehension test in the general population heightens the promise of this measure as a genetic marker for schizophrenia.  相似文献   
105.
Oncologic screenings of the populations in the areas with increased incidence of esophageal cancer have revealed Barrett's ulcer in 1 percent of the examinees. Endoscopic and cytologic characteristics of this condition are presented. Precancer changes--severe dysplasia--are most frequent in male Kazakhs (14.1 percent) aged 50 to 59 (14.7 percent). Subjects with Barrett's ulcer developing severe dysplasia, as evidenced by cytograms, should be included in the group of subjects at risk for carcinoma of the lower third of the esophagus and cardia.  相似文献   
106.
In the period 1979-1980 the following anthropometric measurements were recorded in 2351 healthy Dutch children from 0-17 years of age: height, weight, sitting height, arm span, lengths of upper-arm, lower-arm and hand, tibial length, foot length, biacromial diameter, biiliacal diameter, and head circumference. Corresponding percentile values were constructed on the basis of normality assumptions, the mean and standard deviation at age t being determined by a cubic spline approximation. The results are compared with other studies and given in the form of growth charts.  相似文献   
107.
108.
Advanced malignant melanomas of the uvea unsuited for an eye salvaging approach require enucleation of the tumor containing eye. A series of 68 patients is reported who underwent enucleation combined with insertion of a spherical dura-encased implant after 30 Gray pre-irridiation therapy of the orbit. Postoperative results with special attention to cosmetic outcome and motility of the prosthesis suggest that the insertion of an orbital implant should be preferred to the enucleation with no implant.  相似文献   
109.
The effects of different amounts of dietary zinc on the Zn absorption rate and on Zn, calcium and magnesium concentrations in tissues of MOPC 104E tumor-bearing Balb/c mice were determined. The Zn absorption rate was inversely related to the amounts of Zn in their diets and was lower than that of nontumor-bearing control mice fed a laboratory mice chow. Zn concentrations of tumor-bearing mice were also low compared with control mice but tumor Zn concentrations, regardless of the concentrations of Zn in the diets, were higher than those of normal tissues of the host other than the pancreas. Ca concentrations in tumor and tissues of tumor-bearing mice were higher than in control animals but Mg concentrations in tissues of tumor-bearing mice appeared to be similar to those of control mice. Results suggest that tumor-bearing mice have a lower intestinal Zn absorption capacity and a higher Zn uptake rate causing other tissues to become hypozincemic and hypercalcemic.  相似文献   
110.
A long-term clinical and therapeutic study was performed in 47 patients with mesangial IgA glomerulonephritis. The male to female ratio was 2.9∶1. An episode of gross haematuria or the incidental discovery of asymptomatic microscopic haematuria with associated mild proteinuria heralded the apparent onset of renal disease. At the onset of observation 18 patients (38.2%) had high blood pressure. Other 17 patients developed hypertension during observation. Anaemia was uncommon. No essential abnormalities in serum protein and lipid patterns were found. Twenty-nine patients (61.6%) had higher levels of serum immunoglobulins—most frequently of IgA (42.5%). Twenty-two patients had low serum C3 levels (46.8%). The percentage of patients with renal failure increased from 21.2 to 36.1 during observation. Male sex, hypertension, proteinuria higher than 2 g/24 h, elevated ESR, high serum IgA levels, longer duration of the disease and older age of patients suggest an unfavourable outcome. Long-term treatment with a combination of azathioprine/acenocumarol, or indomethacin, or levamisole has no effect on the clinical manifestation and evolution.  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