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   3993篇
  免费   198篇
  国内免费   18篇
耳鼻咽喉   33篇
儿科学   70篇
妇产科学   44篇
基础医学   539篇
口腔科学   61篇
临床医学   231篇
内科学   945篇
皮肤病学   99篇
神经病学   386篇
特种医学   137篇
外科学   730篇
综合类   16篇
预防医学   111篇
眼科学   79篇
药学   251篇
中国医学   2篇
肿瘤学   475篇
  2023年   18篇
  2022年   29篇
  2021年   73篇
  2020年   41篇
  2019年   41篇
  2018年   55篇
  2017年   63篇
  2016年   63篇
  2015年   65篇
  2014年   80篇
  2013年   101篇
  2012年   198篇
  2011年   196篇
  2010年   122篇
  2009年   120篇
  2008年   173篇
  2007年   177篇
  2006年   206篇
  2005年   202篇
  2004年   225篇
  2003年   221篇
  2002年   191篇
  2001年   131篇
  2000年   136篇
  1999年   132篇
  1998年   53篇
  1997年   58篇
  1996年   45篇
  1995年   48篇
  1994年   40篇
  1993年   60篇
  1992年   82篇
  1991年   72篇
  1990年   75篇
  1989年   76篇
  1988年   63篇
  1987年   68篇
  1986年   62篇
  1985年   59篇
  1984年   19篇
  1983年   25篇
  1982年   20篇
  1981年   15篇
  1980年   16篇
  1979年   37篇
  1978年   19篇
  1977年   13篇
  1975年   18篇
  1973年   19篇
  1972年   15篇
排序方式: 共有4209条查询结果,搜索用时 156 毫秒
61.
62.
This retrospective study aimed to assess the diagnostic performance of contrast-enhanced ultrasound with Sonazoid (S-CEUS) for liver metastasis. We enrolled in this study 98 patients with 148 histologically proven liver lesions, with 121 metastases and 27 non-metastases. The S-CEUS technique showed sensitivity in 95.0% (115 of 121), specificity in 44.4% (12 of 27) and accuracy in 85.8% (127 of 148) for the diagnosis of metastasis. Higher body mass index had a negative influence on the positive predictive value and accuracy, and a greater depth of the lesion had a negative influence on the accuracy. The management was changed in 8 patients (8.2%) because of S-CEUS findings. In conclusion, the addition of S-CEUS may offer a great benefit by improvement of the quality of diagnosis and management for patients with cancer who have a tentative diagnosis of liver metastasis by contrast-enhanced computed tomography.  相似文献   
63.
We examined dermoscopic features of three cases of extraocular sebaceous carcinoma and reviewed the literatures. The yellowish structures, polymorphous vessels and ulceration were common findings in our cases and all cases of the previous reports. The appearance of whitish‐pink areas has not been described previously. Our results suggested that the combination of four dermoscopic features, whitish‐pink areas, yellowish structures, polymorphous vessels and ulceration might be distinctive in extraocular sebaceous carcinoma.  相似文献   
64.
65.
66.
67.
68.
Aim: Twenty patients (14 of them women) suffering from psychophysiological insomnia (PPI) were enrolled for cognitive behavior therapy (CBT). The mean age of the patients was 56.9 years, and the mean duration of insomnia morbidity was 8.9 years. Each received individual combined CBT treatments consisting of stimulus control, sleep reduction, cognitive therapy and sleep hygiene education over a period of 1 month. Methods: Just before the CBT and after its completion, sleep measurements were conducted that involved (i) sleep logs, Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), and the Pittsburgh Sleep Quality Index (PSQI); (ii) actigraphy measurement; (iii) dissociation between subjective and objective evaluation of sleep calculated from sleep logs and actigraphy results; and (iv) correlation between DBAS and the aforementioned sleep parameters. Because the intention was to focus on patients' incorrect cognition about sleep, the definition ‘changes in dissociation between the sleep log and actigraphically measured sleep’ was used as the primary outcome and ‘changes in DBAS score’ as the secondary outcome. Results: After the CBT the following was found: (i) underestimation by PPI patients of the objective evaluation of sleep; (ii) a decrease in the dissociation between the subjective and objective evaluation of sleep; (iii) improvement of the DBAS; and (iv) improvement of sleep logs and actigraphy measurements. Moreover, there was a correlation between the improvement of PSQI, sleep logs and DBAS. Conclusion: CBT for insomnia is able to redress incorrect cognition about sleep, leading to improvement of the disorder.  相似文献   
69.
A cohort of 76 patients with acute myocardial infarction was studied with infarct-avid scan, radionuclide ventriculography, and thallium-201 myocardial perfusion scintigraphy. Infarct area, left ventricular ejection fraction, and defect score were calculated as radionuclide indices of the extent of myocardial infarction. The correlation was studied between these indices and cardiac events (death, congestive heart failure, postinfarction angina, and recurrence of myocardial infarction) in the first postinfarction year. High-risk patients (nonsurvivors and patients who developed heart failure) had a larger infarct area, a lower left ventricular ejection fraction, and a larger defect score than the others. Univariate linear discriminant analysis was done to determine the optimal threshold of these parameters for distinguishing high-risk patients from others. Radionuclide parameters obtained in the early phase of acute myocardial infarction were useful for detecting both patients with grave complications and those with poor late prognosis during a mean follow-up period of 2.6 years.  相似文献   
70.
Summary Atherosclerotic changes have not been demonstrated directly in asymptomatic hyperglycaemic non-diabetic subjects, although high mortality due to coronary heart disease has been reported. We measured arterial wall thickness non-invasively, in order to directly demonstrate atherosclerosis of the carotid arteries of hyperglycaemic non-diabetic subjects and to evaluate its risk factors.The thicknesses of the intimal plus medial complex (IMT) of the carotid arteries of 112 asymptomatic hyperglycaemic non-diabetic subjects (aged 22–81, 95 males and 17 females) were compared with those of 55 healthy male subjects and 211 non-insulin-dependent NIDDM male diabetic patients. The subjects were subgrouped into impaired glucose-tolerant (IGT) subjects who had a 2-h glycaemic level of more than 7.8 mmol/l, and non-IGT subjects whose 2-h glycaemic levels were within 6.7–7.7 mmol/l.Non-IGT and IGT subjects showed significantly greater IMTs than age-matched healthy males and showed no significant differences compared to age-matched NIDDM patients. Multivariate analysis demonstrated that the risk factors for IMT of non-IGT and IGT subjects were age and systolic blood pressure. According to data on the accumulation of atherogenic risks (hypertension, dyslipidaemia, and smoking), IMT increased linearly in non-IGT and IGT subjects. However, non-IGT and IGT subjects without hyperlipidaemia, hypertension, or smoking risk still had significantly greater IMT than age-matched normal males (1.019±0.063 vs 0.770±0.111 mm, p<0.05). Prevalence of ECG-indicated coronary heart disease was significantly higher in hyperglycaemic non-diabetic subjects and NIDDM with increased carotid arterial wall thickness (IMT 1.1 mm) than in those without increased thickness (IMT<1.1 mm). Asymptomatic hyperglycaemic non-diabetic subjects have increased thickness of their carotid arteries compared to age-matched male NIDDM patients. As one of several independent risk factors, mild hyperglycaemia advances atherosclerosis, which leads to coronary heart disease.Abbreviations IMT Intimal plus medial complex - NIDDM non-insulin-dependent diabetes mellitus - IGT impaired glucose tolerance - CHD coronary heart disease - T-Chol serum total cholesterol - HDL-C high-density lipoprotein cholesterol - TG serum triglycerides  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