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   3798篇
  免费   215篇
  国内免费   19篇
耳鼻咽喉   21篇
儿科学   172篇
妇产科学   35篇
基础医学   482篇
口腔科学   105篇
临床医学   300篇
内科学   1014篇
皮肤病学   35篇
神经病学   176篇
特种医学   126篇
外科学   559篇
综合类   13篇
预防医学   100篇
眼科学   150篇
药学   353篇
中国医学   8篇
肿瘤学   383篇
  2023年   18篇
  2022年   29篇
  2021年   55篇
  2020年   26篇
  2019年   27篇
  2018年   69篇
  2017年   26篇
  2016年   60篇
  2015年   74篇
  2014年   75篇
  2013年   103篇
  2012年   128篇
  2011年   137篇
  2010年   100篇
  2009年   94篇
  2008年   133篇
  2007年   196篇
  2006年   178篇
  2005年   149篇
  2004年   170篇
  2003年   167篇
  2002年   143篇
  2001年   128篇
  2000年   125篇
  1999年   156篇
  1998年   117篇
  1997年   76篇
  1996年   88篇
  1995年   66篇
  1994年   57篇
  1993年   55篇
  1992年   103篇
  1991年   100篇
  1990年   93篇
  1989年   80篇
  1988年   57篇
  1987年   64篇
  1986年   68篇
  1985年   48篇
  1984年   35篇
  1983年   30篇
  1982年   20篇
  1981年   29篇
  1980年   20篇
  1979年   38篇
  1978年   23篇
  1976年   19篇
  1972年   18篇
  1971年   21篇
  1970年   18篇
排序方式: 共有4032条查询结果,搜索用时 46 毫秒
51.
52.
53.
Dendriform pulmonary ossification is an extremely rare disease, which is usually found and analysed postmortem. Pathogenesis of pulmonary ossification is therefore still unknown. We describe two males in the same family (a 29 year-old patients and his 58 year-old father) with pulmonary ossification. The young male was symptomatic pneumothorax but his father had been asymptomatic since youth. Familial clustering of pulmonary ossifications strongly suggests a genetic predisposition for the pathogenesis. This is the first report of two cases of dendriform pulmonary ossification in the same family.  相似文献   
54.
OBJECTIVE: CYP2C9 is a polymorphic enzyme, and CYP2C9*3 is associated with decreased metabolic activity. In addition to the impaired metabolism, we investigated whether the CYP2C9*3 exhibited altered inhibitory susceptibility compared with CYP2C9*1. METHOD: In the present study, CYP2C9.1 and CYP2C9.3 were expressed in yeast. Using typical CYP2C9 substrates (diclofenac, tolbutamide and S-warfarin) and a potent CYP2C9 inhibitor (nicardipine), the Ki values for nicardipine on the three metabolisms in CYP2C9*1 and CYP2C9*3 were determined. RESULT: The ratios of Ki(CYP2C9*3)/Ki(CYP2C9*1) on tolbutamide, diclofenac and S-warfarin metabolisms were 1.2, 3.1 and 0.8, respectively. CONCLUSION: In conclusion, there are no significant differences in the inhibitory susceptibility between the two CYP2C9 enzymes.  相似文献   
55.
OBJECTIVE: Loop diuretics such as bumetanide and furosemide cause an acute enlargement of the intrastrial space of the stria vascularis, with an associated decline in the endocochlear DC potential (EP). The aim of this study was to determine the role played by the Na+-K+-ATPase in the bumetanide-induced enlargement of the intrastrial space, and to examine the importance of the balance between the activities of the Na+-K+-2Cl- cotransporter and the Na+-K+-ATPase to the physiological function of the stria vascularis. MATERIAL AND METHODS: Albino guinea pigs were used in experiments involving perilymphatic perfusion, EP measurement and electron microscopy. The effects of bumetanide on the stria vascularis were examined following inhibition of the Na+-K+-ATPase by ouabain. Ouabain was administered to the perfusate and, when the EP reached 0 mV, both ouabain and bumetanide were administered. RESULTS: Although there was no enlargement of the intrastrial space, vacuoles were apparent in marginal cells. The vacuolar change in marginal cells was similar to that caused by ouabain alone. CONCLUSION: This study indicates that the enlargement of the intrastrial space requires not only the blockade of the Na+-K+-2Cl- cotransporter but also normal activity of the Na+-K+-ATPase, and suggests that the bumetanide-induced enlargement of the intrastrial space resulted from the imbalance between the activities of the Na+-K+-2Cl- cotransporter and the Na+-K+-ATPase.  相似文献   
56.
Systematic investigations on the emotional impacts of repeated spontaneous abortions have been few. We mounted a prospective study of a cohort of couples who had experienced two consecutive first trimester spontaneous abortions and for whom no clearly identifiable causes were found. The present report is based on the first part of the study and examines: (1) emotional distress reported by the miscarrying women at six months (median, range 1-12 months) after two abortions; and (2) psychosocial predictors influencing such distress. The mean score of the women on the Symptom Checklist 90-Revised--one of the most popular self-report scales for psychopathology--was 0.38, whereas that for the general population is reported to be 0.26 (the higher the score, the more psychopathology). Fourteen percent of the cohort scored above the cutoff point for mental disorders screening. Factors examined and found non-influential upon the level of emotional distress include: the maternal age; whether the last pregnancy was planned and wished for or not; and coping styles of the women after the abortions. Control by the husbands over the marital relationship and neurotic personality traits of the women increased the emotional distress, whereas the social support the women perceive decreased it. These findings suggest that martial and social support are important in determining the level of psychiatric morbidity after repeated abortions.  相似文献   
57.
58.
An 8 year old girl with acute disseminated encephalomyelitis (ADEM) is described. Elevated serum antibody titers suggested recent Mycoplasma pneumoniae infection. T2-weighted image of magnetic resonance imaging (MRI) disclosed multiple lesions of high signal intensity in bilateral basal ganglia and thalami as well as in the white matter. Postcontrast T1-weighted image revealed an enhanced lesion in the deep white matter. She showed rapid clinical improvement in response to corticosteroid therapy. The lesions had disappeared completely on MRI performed 10 weeks after the onset. ADEM is believed to be a demyelinating disorder of probable autoimmune etiology. MRI findings in this case may support the hypothesis that the primary pathological event is vascular injury and demyelination occurs only as a secondary phenomenon.  相似文献   
59.
The present study examined chronotropic dysfunction and the role of vagotony in congenital long QT syndrome, sinus node function and the effects of parasympathetic blockade. Six patients with congenital long QT syndrome were studied. The four males and two females, aged 1–15 years, had episodes of syncope and malignant ventricular arrhythmias. Congenital long QT syndrome was defined as a corrected QT interval greater than 0.45 s, T wave alternans and the age at diagnosis. The sinus heart rate measured from a 24 h electrocardiograph was abnormally low (< 50 min) in three patients (1, 4 and 5 years old) and did not increase sufficiently with the administration of atropine in five of the six patients with congenital long QT syndrome. From intracardiac electrophysiological studies, the corrected sinus node recovery time was prolonged in three patients and the total sinoatrial conduction time was prolonged in two patients. In most patients who had an abnormally long sinoatrial conduction time and corrected sinus node recovery time, these values returned to normal following atropine administration. In one patient, the corrected sinus node recovery time was prolonged paradoxically by atropine. Sinus node dysfunction in congenital long QT syndrome was affected by vagotony associated with a right sympathetic nerve system abnormality.  相似文献   
60.
The case of a 13 year old boy with an inflammatory esophagogastric polyp and ulcerative colitis is described. Endoscopy revealed a typical polyp and gastric fold complex at the esophagogastric junction and a hiatal hernia. Histology of a biopsy specimen confirmed an inflammatory polyp covered by hyperplastic squamous and gastric foveolar epithelium. Continuous 24 hour esophageal manometry suggested gastroesophageal reflux, which may be related to the pathogenesis of the lesion. Follow-up endoscopy showed marked regression of the polyp with medication for reflux eosphagitis. This clinical entity is rare in childhood and adolescence, and the manifestations may not be readily recognized. Therefore, endoscopic biopsy is important in children with esophageal polyps. However, polypectomy is unnecessary except when malignancy is suspected or when symptoms persist.  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