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   380399篇
  免费   24133篇
  国内免费   2817篇
耳鼻咽喉   5191篇
儿科学   8216篇
妇产科学   10086篇
基础医学   53318篇
口腔科学   11865篇
临床医学   30174篇
内科学   78633篇
皮肤病学   8598篇
神经病学   27267篇
特种医学   13949篇
外国民族医学   82篇
外科学   60723篇
综合类   9964篇
现状与发展   1篇
一般理论   64篇
预防医学   17467篇
眼科学   9448篇
药学   31068篇
  1篇
中国医学   2193篇
肿瘤学   29041篇
  2021年   2644篇
  2019年   2739篇
  2018年   4539篇
  2017年   3453篇
  2016年   3547篇
  2015年   4043篇
  2014年   5722篇
  2013年   7418篇
  2012年   10089篇
  2011年   10273篇
  2010年   6222篇
  2009年   5889篇
  2008年   9533篇
  2007年   10366篇
  2006年   10280篇
  2005年   9336篇
  2004年   8826篇
  2003年   8572篇
  2002年   8256篇
  2001年   28272篇
  2000年   28799篇
  1999年   23692篇
  1998年   5186篇
  1997年   4260篇
  1996年   3838篇
  1995年   3488篇
  1994年   3116篇
  1993年   2856篇
  1992年   16068篇
  1991年   14829篇
  1990年   14179篇
  1989年   13978篇
  1988年   12603篇
  1987年   12070篇
  1986年   11115篇
  1985年   10330篇
  1984年   6915篇
  1983年   5607篇
  1982年   2724篇
  1979年   5487篇
  1978年   3350篇
  1977年   2977篇
  1975年   2642篇
  1974年   3065篇
  1973年   2865篇
  1972年   2830篇
  1971年   2776篇
  1970年   2513篇
  1969年   2544篇
  1968年   2254篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A Akasawa  N Koya  Y Iikura 《Arerugī》1991,40(4):428-434
Twenty-two twins' families were investigated to determine the influence of a genetic factor in the etiology of allergic diseases in children. Zygosity was confirmed by eight red cell blood types and HLA type. Eight pairs of monozygotic twins were divided by a probability of monozygosity as calculated from Essen-M?ller's method. Concordance rate of allergic disease and asthma were 88% in MZ, 86% in DZ, 75%, 73% and that of positive rate of DF-specific IgE antibody were 60% in MZ, 58% in DZ. In DZ, not sharing the same HLA haplotypes, concordance of the positive rate of DF-specific IgE antibody was 0%. Concomitant coefficiency of total serum IgE levels were 0.593 in MZ, 0.063 in DZ. These data suggested that IgE production may be influenced by genetic factors.  相似文献   
992.
Spectral slope of vowels produced by tracheoesophageal speakers   总被引:1,自引:0,他引:1  
Spectra of vowels were analyzed to determine whether differences exist between the spectral slope of vowels produced by tracheoesophageal (TE) speakers and normal speakers and, if so, to quantify such differences. The linear predictive autocorrelation method was used to calculate smoothed spectra and the spectra were normalized with respect to a low frequency component. Comparisons between normalized spectral energy within a selected high frequency range revealed that energy within this frequency range for vowels produced by TE speakers was significantly higher than that produced by normal speakers. A least-square distance matching procedure was used to quantify speaker group differences in the spectral slope of vowels. Average spectra of vowels produced by the normal speakers could be matched to average spectra of vowels produced by the TE speakers by decreasing the spectral slope of their vowels by 2-3 dB/octave.  相似文献   
993.
Nineteen cases of mid-trimester pregnancy were terminated using prostaglandin E2 gel applied intracervically. In this prospective study, 42% were primipara with gestational age at the time of abortion between 16 and 28 weeks. The induction to abortion time was 19.65 +/- 10.37 h with a success rate of 89%. The average number of applications was 1.8 times (range 1-3 times) and the average dosage of prostaglandin required was 5.5 mg (range 3-9 mg). The complications were minimal except retained placenta in 42% of cases. Prostaglandin E2 in form of gel applied intracervically is an effective alternative to the commonly used hypertonic saline or, more recently, to prostaglandin analogues for termination of pregnancy in the second trimester.  相似文献   
994.
To differentiate focal nodular hyperplasia (FNH) from other hepatic tumors, especially hepatocellular carcinoma, we evaluated the hemodynamics of histologically proved FNH in three patients, two by arterial angio-CT and one by microangiography of the resected specimen. These studies demonstrated the centrifugal blood supply of FNH (early filling of central tumor vessels radiating to periphery, and lobulated tumor stains with central low density area in the late phase), which could not be demonstrated by dynamic CT or hepatic angiography. Arterial angio-CT is useful as a further study, when differential diagnosis of FNH is uncertain by other imaging techniques.  相似文献   
995.
996.
Polyester-crystic cast was observed to reach the peritubular capillary plexus following injection in sheep kidneys. Microvascular structures in this region are also reported in this study. Glomeruli were found to vary in size and shape. Diameters of afferent arterioles were larger than those of efferent arterioles. The glomerulus is supplied by more than one afferent arteriole, and in some regions, the blood in afferent arterioles joins collateral circulation via the intercapillary plexus. Morphological properties at the end of the peritubular capillary plexus were found to be remarkably significant.  相似文献   
997.
A 23-year-old male with bronchial asthma developed eosinophilia (eosinophils greater than 2,000/mm3) and was observed at our hospital. After using a prescribed indomethacin suppository for fever at home, he experienced an attack of acute chest pain and severe dyspnea. He suffered cardiac arrest while being transferred to the ward. After resuscitation, he was diagnosed as having acute myocardial infarction on the basis of electrocardiographic and ultrasonic cardiographic findings, and marked elevation of serum concentrations of myocardial enzymes. Thereafter, he often complained of precordial pain and abdominal pain. When he was administered an analgesic in another hospital, he developed severe precordial pain, and marked ST elevation was recorded on the electrocardiogram. Coronary angiography revealed no stenosis nor atherosclerotic changes, suggesting that severe spasm of the coronary arteries and direct myocardial injury by eosinophils were the causes of the myocardial infarction-like symptoms and angina pectoris-like attacks. He was diagnosed as having Churg-Strauss syndrome (allergic granulomatous angiitis) on the basis of the clinical findings; skin biopsy and transbronchial lung biopsy findings were consistent with the diagnosis. Following steroid administration, his angina-like attacks and abdominal pain ceased. This patient developed two episodes of acute cardiovascular symptoms upon administration of antipyretic analgesics. This suggests that in cases of Churg-Strauss syndrome with aspirin-induced asthma, physicians must be aware of the cardiovascular complications, and such drugs should be administered with caution.  相似文献   
998.
999.
Clinical features of 16 patients with mild systemic lupus erythematosus (SLE) were compared with those of 21 control patients with moderate or severe disease. Age at the time of diagnosis of SLE was higher in mild disease group. The incidence of the coexistence of Sj?gren's syndrome (SS) at the time of diagnosis of SLE was higher in patients who later developed mild disease. Anti-Sm antibody and decreased levels of C3, C4, and CH50 occurred less frequently in patients with mild disease. SLE patients with the coexistence of SS at the time of diagnosis of SLE may represent a subset with a benign prognosis.  相似文献   
1000.
A case-control study was conducted to examine factors relating to discontinuation of domiciliary care for the bedridden elderly in Shinagawa-ku, Tokyo. Cases were bedridden residents aged 65 years and over who had abandoned home care and applied for admission to live in a special nursing home for the aged between April and September in 1990 after being recipients of welfare allowances for disabled elderly. Controls were bedridden residents who continued to be given home care and matched to cases by sex, age and beginning month of the receiving of allowances. Among 50 cases and 94 controls interviewed, we obtained responses from 31 cases (62%) and 60 controls (64%). The main results were as follows: 1. During the home-care period, ADL (activities of daily living) of cases, especially walking ability, deteriorated more severely than in controls. Night delirium also appeared more frequently in cases. 2. The primary caregivers of cases were older than those of controls. Remarkable differences between cases and controls were observed in the family structure, the number of family members and the number of sub-caregivers. Cases tended to live alone or live with a spouse only, and with smaller number of family members and caregivers. 3. Case lived more frequently in houses with small numbers of rooms and without rooms of their own. 4. As regards utilization of domiciliary care services, cases used dispatch of home helpers more frequently and used day services less frequently.  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