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   5448篇
  免费   620篇
  国内免费   168篇
耳鼻咽喉   55篇
儿科学   227篇
妇产科学   140篇
基础医学   166篇
口腔科学   78篇
临床医学   1222篇
内科学   1215篇
皮肤病学   113篇
神经病学   357篇
特种医学   179篇
外科学   1576篇
综合类   19篇
预防医学   309篇
眼科学   326篇
药学   36篇
肿瘤学   218篇
  2023年   109篇
  2021年   63篇
  2020年   99篇
  2019年   43篇
  2018年   126篇
  2017年   174篇
  2016年   185篇
  2015年   141篇
  2014年   228篇
  2013年   295篇
  2012年   100篇
  2011年   114篇
  2010年   234篇
  2009年   343篇
  2008年   121篇
  2007年   67篇
  2006年   101篇
  2005年   77篇
  2003年   47篇
  2002年   39篇
  2001年   104篇
  2000年   66篇
  1999年   133篇
  1998年   177篇
  1997年   202篇
  1996年   301篇
  1995年   254篇
  1994年   195篇
  1993年   115篇
  1992年   121篇
  1991年   134篇
  1990年   65篇
  1989年   129篇
  1988年   101篇
  1987年   78篇
  1986年   100篇
  1985年   83篇
  1984年   87篇
  1983年   74篇
  1982年   66篇
  1981年   62篇
  1980年   80篇
  1979年   39篇
  1978年   59篇
  1977年   42篇
  1976年   43篇
  1975年   45篇
  1972年   36篇
  1964年   49篇
  1963年   47篇
排序方式: 共有6236条查询结果,搜索用时 15 毫秒
71.
72.
73.
Chronic pancreatitis: ultrasonic features   总被引:2,自引:0,他引:2  
Alpern  MB; Sandler  MA; Kellman  GM; Madrazo  BL 《Radiology》1985,155(1):215-219
A retrospective analysis of 84 ultrasound examinations (in 77 patients) was performed to assess the frequency of sonographic findings in chronic pancreatitis. The findings included: inhomogeneously increased echogenicity in 53% of these examinations, focal or diffuse enlargement in 41%, focal dense echoes in 40%, pseudocyst formation in 21%, and a hypoechoic head mass in 7%. Thirteen per cent of our patients had a normal sonogram. Several presentations of chronic pancreatitis not previously described in the sonographic literature included: pancreatic or common bile duct enlargement or pseudocyst formation with otherwise normal-appearing glands. There was no direct relationship between the presence of focal high-intensity echoes within the pancreatic parenchyma and the presence of radiographic calcification. There was no difference in the frequency of ultrasonic abnormalities between patients with and without clinical evidence of pancreatic insufficiency. These results indicate that the sonographic findings in chronic pancreatitis are significantly more varied than previous reports would indicate.  相似文献   
74.
75.
The newly recognized class of 5-hydroxytryptamine receptors (5HT3) may be involved in the induction of nausea, since their pharmacological antagonists are effective against emesis induced by chemotherapy. 5HT3 receptors are present on enteric neurons, and 5HT3 blockers may produce mild constipation; we thus hypothesized that 5HT3 receptors would modulate colonic motility. To determine if GR 38032F, a selective 5HT3 antagonist known to have antiemetic effects, influences colonic transit in health, a randomized, double-blind, placebo-controlled crossover study was performed. Using a radiopaque marker technique, colonic transit was quantified in 39 healthy volunteers (19 men, 20 nonpregnant women) 18–70 years of age. On a standard 25-g fiber diet, 16 mg of GR 38032F was given orally thrice daily. Gastrointestinal peptides (peptide YY, human pancreatic polypeptide, neurotensin, motilin, gastrin-cholecystokinin, substance P) were also measured in plasma fasting and postprandially. Mean total colonic transit time on placebo was 27.8 hr, while on GR 38032F it was 39.1 hr (P<0.0005). Transit times through the left colon (P<0.0005) and rectosigmoid (P<0.05) were prolonged by the drug, but right colonic transit was not significantly altered. Transit times did not correlate with age or gender, but subjects with shorter transit times were significantly more affected than were those with longer transit times. The peak release of peptide YY was minimally decreased following GR 38032F (P<0.01), but the peak and integrated postprandial responses of human pancreatic polypeptide, neurotensin, motilin, gastrin-cholecystokinin, and substance P were not significantly altered by the drug. We conclude that 5HT3 receptors may be involved in the regulation of colonic transit in healthy man.Supported in part by a grant from Glaxo Group Research, Ltd., and the Mayo Digestive Disease Center (grant DK34988, National Institutes of Health, Bethesda, Maryland).Presented, in part, at the American Motility Socicty in October 1988, and published as an abstract inGastroenterology 95:891, 1988.  相似文献   
76.
Eleven patients with acquired prolongation of the Q-Tc interval and recurrent ventricular tachyarrhythmias were studied. Five patients required 5 to 44 direct current shocks to correct prolonged ventricular tachyarrhythmias, and five were given at least two antiarrhythmic agents in an attempt to control the arrhythmias. In 4 of the 11 patients, when thioridazine, diuretic drugs and antiarrhythmic agents were withdrawn and hypokalemia or hypocalcemia corrected, ventricular tachyarrhythmias did not recur. The Q-Tc interval normalized in 2 to 3 days. Ventricular tachyarrhythmias were recurrent in the remaining seven patients, despite withdrawal of the drugs that caused the Q-Tc prolongation, attempted correction of hypokalemia when present and the administration of antiarrhythmic agents to four of the seven. All antiarrhythmic agents were then withdrawn in this group.

Immediately on the establishment of overdrive ventricular or atrioventricular sequential pacing in these patients, ventricular tachyarrhythmias were abolished. No breakthrough ventricular tachyarrhythmias occurred during temporary pacing. Temporary pacing was required for an average of 10 days and the Q-Tc interval normalized an average of 5 days from the onset of pacing. Three patients required a permanent pacemaker, one because of chronic complete heart block, one because of the sick sinus syndrome, and one because of frequent ventricular ectopic complexes complicating ischemic heart disease. All 11 patients survived their period of hospitalization.  相似文献   

77.
In dogs with gastric fistulae and Heidenhain pouches, inhibition of histamine-stimulated gastric acid secretion by the histamine H2-receptor antagonist metiamide is not increased by the addition of a histamine H1-receptor antagonist (mepyramine maleate). Under the conditions of this study there is no evidence for the presence of histamine H1-receptor sites on the gastric parietal cell.Financial assistance was provided by the South African Medical Research Council.  相似文献   
78.
79.

Background

This research examined whether young adults with Type 1 diabetes engage with the multidisciplinary consultation process and if not, then why.

Methods

We designed a web‐based self‐reported survey, available online from February to May 2011, for Australian adults 18–35 years with Type 1 diabetes. Respondents were asked about which clinicians they consulted to assist with self‐management. To expand on the results of the survey, we interviewed 33 respondents.

Results

Survey: Respondents (n = 150) consulted with the following clinicians: endocrinologist and diabetes educators: 23.3%; endocrinologist only: 18.0%; endocrinologist, diabetes educators and dieticians: 14.6%; endocrinologist, diabetes educators, dietician and general practitioners (GP): 11.3%; endocrinologist and GP: 10.6%; GP only: 4.6%; all clinicians recommended to assist with self‐management: 1.3%; 2.7% did not consult any clinician. Interview: Participants (n = 33) reported eight key disincentives to consultation with multidisciplinary clinicians. These were time constraints; provision of conflicting advice; inaccessibility of health services; variation in service standards; cost constraints; failure of clinicians to refer to other clinicians; lack of opportunity to build a therapeutic relationship; and failure of clinicians to engage in shared decision making.

Conclusion

Our results indicate that high attrition rates of young adults with Type 1 diabetes from recommended diabetes health services is linked to the failure of those services to meet the needs and preferences of their patients. The identified needs and preferences included joint consultation with multi‐disciplinary team clinicians; flexible access to advice by email or telephone consultation; and shared decision making. Patient engagement in health‐service re‐design has implications for improved health‐service delivery and enhanced treatment outcomes.  相似文献   
80.
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