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   3324篇
  免费   183篇
  国内免费   22篇
耳鼻咽喉   48篇
儿科学   76篇
妇产科学   78篇
基础医学   612篇
口腔科学   112篇
临床医学   255篇
内科学   737篇
皮肤病学   98篇
神经病学   248篇
特种医学   157篇
外科学   339篇
综合类   27篇
预防医学   232篇
眼科学   50篇
药学   234篇
中国医学   25篇
肿瘤学   201篇
  2023年   25篇
  2022年   30篇
  2021年   74篇
  2020年   50篇
  2019年   75篇
  2018年   117篇
  2017年   89篇
  2016年   86篇
  2015年   105篇
  2014年   119篇
  2013年   172篇
  2012年   260篇
  2011年   276篇
  2010年   151篇
  2009年   95篇
  2008年   174篇
  2007年   204篇
  2006年   189篇
  2005年   179篇
  2004年   156篇
  2003年   169篇
  2002年   161篇
  2001年   30篇
  2000年   31篇
  1999年   30篇
  1998年   22篇
  1997年   22篇
  1996年   17篇
  1995年   12篇
  1994年   14篇
  1993年   12篇
  1992年   16篇
  1991年   22篇
  1990年   11篇
  1989年   20篇
  1988年   27篇
  1987年   19篇
  1986年   21篇
  1985年   30篇
  1984年   21篇
  1983年   14篇
  1980年   11篇
  1978年   12篇
  1977年   9篇
  1976年   13篇
  1974年   11篇
  1973年   9篇
  1971年   15篇
  1970年   12篇
  1966年   9篇
排序方式: 共有3529条查询结果,搜索用时 15 毫秒
61.
62.
Chin tuck has been has been widely used to prevent aspiration in the patients with dysphagia. This study was performed to investigate the effectiveness and the degree of optimal neck flexion of chin tuck. Ninety-seven patients who showed aspiration in the videofluoroscopic swallow study (VFSS). Participants were grouped into the effective (patients who showed effect with chin tuck) and ineffective group (those who did not show effect with chin tuck). VFSS was performed in neutral and chin tuck position and findings were compared between the groups. Severity of aspiration was assessed by the point penetration-aspiration scale. Duration of dysphagic symptoms, history of tracheostomy, and other possible contributing factors were also compared. Neck flexion angle was measured to find appropriate posture in which aspiration was prevented with chin tuck. Aspiration was reduced or eliminated in only 19 patients (19.6 %) with chin tuck. Oral transit time, pharyngeal delayed time and pharyngeal transit time were significantly shortened in both groups (p < 0.05), but the difference between the groups was not significant. Female sex and absence of residue in pyriform sinus favored the effect of chin tuck (p < 0.05). At least 17.5° of neck flexion was required to achieve an effect with chin tuck. The effectiveness of chin tuck was less than anticipated. Patients without residue in pyriform sinus were more likely to benefit from chin tuck. Sufficient neck flexion was important in chin tuck to prevent aspiration.  相似文献   
63.
The ALAT and SEPAR Treatment and Control of Smoking Groups have collaborated in the preparation of this document which attempts to answer, by way of PICO methodology, different questions on health interventions for helping COPD patients to stop smoking.The main recommendations are: (i) moderate-quality evidence and strong recommendation for performing spirometry in COPD patients and in smokers with a high risk of developing the disease, as a motivational tool (particularly for showing evidence of lung age), a diagnostic tool, and for active case-finding; (ii) high-quality evidence and strong recommendation for using intensive dedicated behavioral counselling and drug treatment for helping COPD patients to stop smoking; (iii) high-quality evidence and strong recommendation for initiating interventions for helping COPD patients to stop smoking during hospitalization with improvement when the intervention is prolonged after discharge, and (iv) high-quality evidence and strong recommendation for funding treatment of smoking in COPD patients, in view of the impact on health and health economics.  相似文献   
64.
Background One of the most common side effects of anti‐cancer therapies is treatment‐induced skin changes, referred to as dermatological toxicities. These dermatological toxicities are noteworthy since they have a negative association with quality of life (QoL). Objectives To evaluate the impact of dermatological toxicities on QoL of cancer patients and to identify the relationship between disease‐related characteristics and QoL and changes in skin protective behaviours following anti‐cancer therapy. Methods Cancer patients (n = 80: stage II–IV) in a longitudinal prospective study completed a battery of questionnaires at the time of enrolment and after 3 months of anti‐cancer therapy. QoL, skin toxicities, smoking and drinking behaviour, sun‐protective and skin care behaviour assessments were performed before and at 3 months after anti‐cancer therapy. QoL was measured with the Dermatology Life Quality Index (DLQI). Results A total of 73 patients completed the study. Among them, 48 patients (65.8%) experienced at least grade 1 skin toxicity at 3 months after anti‐cancer therapy. Hair loss, hyperpigmentation and dry skin were the most common dermatological toxicities. The mean baseline DLQI score changed from 1.38 to 3.49 at 3 months after anti‐cancer therapy. Domain 1 (symptoms and feelings, 1.38 points) was the most greatly impacted among patients by anti‐cancer treatment. Patients who experienced at least grade 1 skin toxicity (P = 0.001, 95% CI: 1.939–4.899), employed (P = 0.042, 95% CI: 0.030–1.476), more highly educated (P = 0.030, 95% CI: 0.161–3.132), and diagnosed with gastric cancer (P = 0.001, 95% CI: 2.141–8.250) or renal cell cancer (P = 0.002, 95% CI: 2.731–11.364) showed significantly higher DLQI scores. Patients showed significant change in skin protective behaviour such as use of body moisturizer (P = 0.021) and change in drinking behaviour (P = 0.006) at 3 months following anti‐cancer therapy. Conclusion Dermatological toxicities due to anti‐cancer therapy affect the QoL of cancer patients. Therefore, health care professionals should pay attention to the psychological effects of skin problems and educate cancer patients to adapt proactive skin protective behaviours to minimize dermatological toxicities of anti‐cancer therapy and maximize QoL.  相似文献   
65.
66.
BACKGROUND: It has been suggested that genes related to Amerindian ancestry account for the high prevalence of gallstone disease (GD) observed in Mexican-Americans. The HLA-B39 is an allele found in higher frequency in Amerindians whereas HLA-B15 is rarely found. The aim of this study was to test the hypothesis that gallstone susceptibility genes are more prevalent in Mexicans with recent Amerindian ancestry. METHODS: We carried out a prospective case-controlled study. Subjects were divided into those who had stones visible on gallbladder ultrasound (cases), and those whose ultrasounds were negative for gallstones (controls). Body mass index (BMI) was calculated, and serum lipids and lipoprotein, and glucose levels were measured. Class I HLA (HLA-B) typing was performed by PCR amplification of genomic DNA. RESULTS: Of the 1,101 subjects, 146 were classified as subjects with GD (cases) and 955 as subjects without GD (controls). Mean age of the cases was 53.5 +/- 12.5 yr versus 44.78 +/- 12.0 yr for the controls, p= 0.001. A family history of GD was observed in 48% of the cases versus 28.4% of the controls, p= 0.001. HLA-B39 was more frequently increased in GD subjects (0.162), compared with controls (0.063), p= 0.008. The odds ratio of having HLA-B39 was 2.8 and 95% (CI 95%= 1.3-6.3) for GD; HLA-B15 was more frequently increased in controls than in cases. CONCLUSIONS: The most prevalent HLA alleles detected in these GD cases are characteristic of Amerindian populations, supporting the role of genetics in the high prevalence of the development of GD in Mexican mestizos.  相似文献   
67.
The incidence of hepatocarcinoma (HCC) has increased in industralized countries. Its relation with hepatitis C virus (HCV) has already been established. The mechanisms by which HCV promotes HCC development are poorly understood. The continuous necrotic and inflammatory effect with subsequent liberation of various cytoquines and modifications in hepatocyte genome have been proposed. Chronic infection with HCV leads to chronic liver disease and cirrhosis which is described as the main precursory lesion to HCC. The assessment methods for patients with chronic liver diseases allow those patients with high risk for HCC to be identified and the process to identify this tumor at an early stage to be initiated.  相似文献   
68.
69.
Along with recent developments in deep learning techniques, computer-aided diagnosis (CAD) has been growing rapidly in the medical imaging field. In this work, we evaluate the deep learning-based CAD algorithm (DCAD) for detecting and localizing 3 major thoracic abnormalities visible on chest radiographs (CR) and to compare the performance of physicians with and without the assistance of the algorithm. A subset of 244 subjects (60% abnormal CRs) was evaluated. Abnormal findings included mass/nodules (55%), consolidation (21%), and pneumothorax (24%). Observer performance tests were conducted to assess whether the performance of physicians could be enhanced with the algorithm. The area under the receiver operating characteristic (ROC) curve (AUC) and the area under the jackknife alternative free-response ROC (JAFROC) were measured to evaluate the performance of the algorithm and physicians in image classification and lesion detection, respectively. The AUCs for nodule/mass, consolidation, and pneumothorax were 0.9883, 1.000, and 0.9997, respectively. For the image classification, the overall AUC of the pooled physicians was 0.8679 without DCAD and 0.9112 with DCAD. Regarding lesion detection, the pooled observers exhibited a weighted JAFROC figure of merit (FOM) of 0.8426 without DCAD and 0.9112 with DCAD. DCAD for CRs could enhance physicians’ performance in the detection of 3 major thoracic abnormalities.  相似文献   
70.
Background: Fractional flow reserve (FFR) has become a useful tool in the assessment of physiological significance of coronary artery stenosis (CAS), and Adenosine (ADE) is associated with a high incidence of transient side effects. Sodium nitroprusside (NPS) has been proposed as an alternative vasodilator agent. A meta-analysis of studies comparing ADE and NPS for FFR assessment in the same coronary lesions was performed.

Methods: Authors searched for articles comparing NPS and ADE for FFR assessment in intermediate coronary lesions published through January 2018. The following keywords were used: ‘fractional flow reserve’ AND ‘nitroprusside’. Data were summarized using weighted mean differences for paired data.

Results: Seven studies were identified comprising 342 patients and 401 lesions. Four studies evaluated intravenous ADE and 3 studies intracoronary ADE administration. Weighted means FFR values obtained with ADE and NPS were 0.8411 and 0.8445, respectively (weighted mean difference: 0.00, 95% confidence interval (CI) ?0.01 to 0.01, p = 0,548). Adverse events were significantly reduced with IC NPS (RR = 0.08, 95%CI 0.02–0.30, P < 0.0001).

Conclusions: NPS produces similar FFR measurements compared to ADE with a significant reduction in adverse effects. These results may support its use as a suitable alternative to ADE for FFR assessment.  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