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   1113篇
  免费   68篇
  国内免费   4篇
耳鼻咽喉   9篇
儿科学   62篇
妇产科学   6篇
基础医学   129篇
口腔科学   20篇
临床医学   141篇
内科学   257篇
皮肤病学   25篇
神经病学   45篇
特种医学   182篇
外科学   62篇
综合类   16篇
一般理论   1篇
预防医学   108篇
眼科学   6篇
药学   55篇
肿瘤学   61篇
  2022年   11篇
  2021年   12篇
  2020年   5篇
  2019年   19篇
  2018年   28篇
  2017年   10篇
  2016年   15篇
  2015年   27篇
  2014年   31篇
  2013年   39篇
  2012年   42篇
  2011年   53篇
  2010年   40篇
  2009年   44篇
  2008年   33篇
  2007年   35篇
  2006年   38篇
  2005年   41篇
  2004年   30篇
  2003年   26篇
  2002年   13篇
  2001年   18篇
  2000年   12篇
  1999年   9篇
  1998年   36篇
  1997年   51篇
  1996年   48篇
  1995年   36篇
  1994年   19篇
  1993年   23篇
  1992年   16篇
  1991年   21篇
  1990年   15篇
  1989年   28篇
  1988年   38篇
  1987年   32篇
  1986年   29篇
  1985年   21篇
  1984年   9篇
  1983年   11篇
  1982年   7篇
  1981年   17篇
  1980年   6篇
  1979年   7篇
  1978年   10篇
  1977年   9篇
  1976年   9篇
  1975年   12篇
  1971年   4篇
  1941年   6篇
排序方式: 共有1185条查询结果,搜索用时 15 毫秒
91.
Objectives – To evaluate the feasibility and safety of head‐neck cooling in conscious normal volunteers (10) and patients with medically refractory epilepsy (5) without causing shivering. Patients and methods – We used a non‐invasive head‐neck cooling system (CoolSystems Inc., Lincoln, CA, USA). The tympanic temperature (TT) and intestinal temperature (IT) were measured as two measurements of ‘core temperature’ (CT), and multi‐site external temperatures, several physiologic variables and EEG were monitored. Seizure counts over 4‐week precooling, treatment and follow‐up phases were compared. Results – All 15 participants completed all the cooling sessions without significant complaints. At the end of 60 min of cooling, scalp temperature fell on average by 12.2°C (P < 0.001), TT by 1.67°C (P < 0.001), and IT by 0.12°C (P = NS). Average weekly seizure frequency decreased from 2.7 to 1.7 events per patient per week (MANOVA: P < 0.05). Conclusions – Non‐invasive head‐neck cooling is safe and well‐tolerated. Initial pilot data in patients suggest that additional therapeutic studies are warranted.  相似文献   
92.

Objective

Explore the perceived benefits of a Veterans Health Administration (VHA) geriatric specialty telemedicine service (GRECC Connect) among rural, older patients and caregivers to contribute to an assessment of its quality and value.

Data Sources

In Spring 2021, we interviewed a geographically diverse sample of rural, older patients and their caregivers who participated in GRECC Connect telemedicine visits.

Study Design

A cross-sectional qualitative study focused on patient and caregiver experiences with telemedicine, including perceived benefits and challenges.

Data Collection

We conducted 30 semi-structured qualitative interviews with rural, older (≥65) patients enrolled in the VHA and their caregivers via videoconference or phone. Interviews were recorded, transcribed, and analyzed using a rapid qualitative analysis approach.

Principal Findings

Participants described geriatric specialty telemedicine visits focused on cognitive assessments, tailored physical therapy, medication management, education on disease progression, support for managing multiple comorbidities, and suggestions to improve physical functioning. Participants reported that, in addition to prescribing medications and ordering tests, clinicians expedited referrals, coordinated care, and listened to and validated both patient and caregiver concerns. Perceived benefits included improved patient health; increased patient and caregiver understanding and confidence around symptom management; and greater feelings of empowerment, hopefulness, and support. Challenges included difficulty accessing some recommended programs and services, uncertainty related to instructions or follow-up, and not receiving as much information or treatment as desired. The content of visits was well aligned with the domains of the Age-Friendly Health Systems and Geriatric 5Ms frameworks (Medication, Mentation, Mobility, what Matters most, and Multi-complexity).

Conclusions

Alignment of patient and caregiver experiences with widely-used models of comprehensive geriatric care indicates that high-quality geriatric care can be provided through virtual modalities. Additional work is needed to develop strategies to address challenges and optimize and expand access to geriatric specialty telemedicine.  相似文献   
93.
94.
OBJECTIVES: This study examined the association of smoking with serum levels and dietary intakes of antioxidants in a nationally representative sample. METHODS: This study classified 7873 apparently healthy adults aged 17 to 50 years from National Health and Nutrition Examination Survey III (NHANES III) data as nonsmokers or as smokers if their serum cotinine levels were either lower than 14 ng/mL or 14 ng/mL or greater, respectively. SUDAAN software was used for the statistical analysis. RESULTS: Smokers of both sexes had significantly (P < .001) lower serum levels of vitamin C, alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin. Reduction in the serum vitamin E, lycopene, and selenium levels in smokers was slight. Smokers also had significantly lower dietary intakes of vitamin C and beta-carotene. A significant (P < .001) inverse relation was found between serum vitamin C and beta-carotene levels and cotinine levels independent of diet effect, and a positive relation (P < .001) was found between serum levels and dietary intakes. CONCLUSIONS: Antioxidants appear to have differing declines in serum levels as a result of reduced dietary intakes and the effects of smoking.  相似文献   
95.
The effects of vitamin D and parathyroid hormone (PTH) levels on incident fracture remain uncertain. To test the hypothesis that increasing serum 25‐hydroxyvitamin D [25(OH)D] and decreasing PTH levels are associated with decreased risk of hip and any nonspine fracture, we conducted a prospective cohort study among 2614 community‐dwelling white and black participants, aged ≥70 years, from the Health, Aging and Body Composition (Health ABC) Study. Serum and plasma samples were drawn at year 2, which formed the baseline for this analysis. Serum 25(OH)D and intact PTH (1‐84) were measured using radioimmunoassay with DiaSorin reagents and EDTA plasma with a two‐site immunoradiometric assay kit, respectively. Incident fractures (hip and any nonspine) were assessed after year 2, every 6 months, by self‐report and validated by radiology reports. The median (interquartile range) follow‐up times for hip and any nonspine fractures were 6.4 (6.1–6.5) and 6.4 (5.5–6.5) years, respectively. Cox proportional hazards regression was used to estimate the hazard ratios (HR) with 95% confidence intervals (CI) for fracture. There were 84 hip and 247 nonspine fractures that occurred over the follow‐up period. The multivariable adjusted HRs (95% CIs) of hip fracture for participants in the lowest (≤17.78 ng/mL), second (17.79 to 24.36 ng/mL), and third quartiles (24.37 to 31.94 ng/mL) of 25(OH)D were 1.92 (0.97 to 3.83), 0.75 (0.32 to 1.72) and 1.86 (1.00 to 3.45), respectively, compared with participants in the highest 25(OH)D quartile (>31.94 ng/mL) (p trend = 0.217). Additional adjustment for IL‐6 (p = 0.107), PTH (p = 0.124), and hip areal bone mineral density (p = 0.137) attenuated HRs of hip fracture in the lowest quartile by 16.3%, 17.4%, and 26.1%, respectively. There was no evidence of an association between 25(OH)D and any nonspine fractures, or between PTH and hip or any nonspine fractures. We found limited evidence to support an association between calciotropic hormones and hip and nonspine fractures in older men and women. © 2012 American Society for Bone and Mineral Research.  相似文献   
96.
OBJECTIVE: To determine the association between Medicaid managed care pediatric behavioral health programs and unmet need for mental health care among children with special health care needs (CSHCN). DATA SOURCE: The National Survey of CSHCN (2000-2002), using subsets of 4,400 CSHCN with Medicaid and 1,856 CSHCN with Medicaid and emotional problems. Additional state-level sources were used. STUDY DESIGN: Multilevel models investigated the association between managed care program type (carve-out, integrated) or fee-for-service (FFS) and reported unmet mental health care need. DATA COLLECTION/EXTRACTION METHODS: The National Survey of CSHCN conducted telephone interviews with a sample representative at both the national and state levels. PRINCIPAL FINDINGS: In multivariable models, among CSHCN with only Medicaid, living in states with Medicaid managed care (odds ratio [OR]=1.81; 95 percent confidence interval: 1.04-3.15) or carve-out programs (OR=1.93; 1.01-3.69) were associated with greater reported unmet mental health care need compared with FFS programs. Among CSHCN on Medicaid with emotional problems, the association between managed care and unmet need was stronger (OR=2.48; 1.38-4.45). CONCLUSIONS: State Medicaid pediatric behavioral health managed care programs were associated with greater reported unmet mental health care need than FFS programs among CSHCN insured by Medicaid, particularly for those with emotional problems.  相似文献   
97.
Insulin-like growth factor-1 (Igf-1), a critical mediator of tissue repair, is significantly decreased in diabetic wounds. Furthermore, decreased levels of hypoxia-inducible factor 1-alpha (Hif-1alpha) and its target genes are also associated with impaired wound healing in diabetic mice. The aim of our study was to examine whether the reduced levels of Igf-1 are responsible for the reduction in Hif-1alpha protein synthesis and activity in diabetic wounds. We provide evidence that Igf-1 regulates Hif-1alpha protein synthesis and activity during wound repair. In addition, Igf-1 stimulated phosphytidylinositol 3-kinase activity in diabetic fibroblasts, which, in turn, increased activation of the translational regulatory protein, p70 S6 kinase. Moreover, improved healing of diabetic wounds by addition of recombinant IGF-1 protein was associated with an increase in Hif-1alpha protein synthesis and function in vivo.  相似文献   
98.
Scientific literature shows that physicians who engage in clinical prevention practices (CPP) have an influence on population health. This is why they are encouraged to apply such practices to promote healthy lifestyle habits in their patients, such as exercise, a healthy diet, and smoking cessation. However, as revealed in a recent study published in the Canadian journal of Public Health, lack of time is the main barrier for doctors in applying CPP. Following upon the results presented in their study, the authors suggest certain solutions that are likely to facilitate prevention practices. The goal of this commentary is to familiarize readers with another potential solution, relatively unknown in Canada, namely computer-tailoring. This innovative intervention method has the potential to facilitate prevention counselling because it provides a means of interacting with a large audience by formulating "customized" educational messages for each member.  相似文献   
99.
INTRODUCTION: Submandibular lymph nodes (SLN) are important for immune responses to antigens in the eye and oral mucosa. Athletes and exercise participants may be at increased risk of ocular, oral, and upper respiratory tract infections. PURPOSE: This study was conducted to examine the effects of voluntary training on the distribution, number, and apoptotic status of SLN lymphocytes in response to an acute bout of strenuous exercise. METHODS: Female C57BL/6 mice were assigned to voluntary wheel-running (WR) exercise (N=20) or were sedentary (N=10) for 16 wk. SLN lymphocytes were examined immediately (EX+Imm) or 24 h (EX+24 h) following strenuous treadmill exercise, or exposure to treadmill conditions without running (NonEX). Intracellular glutathione (GSH), mitochondrial membrane potential (MMP), cell viability (propidium iodide uptake, PI), surface phosphatidylserine (Annexin V), T-lymphocyte (CD3, CD4, CD8), and B-lymphocyte (CD19) phenotype distribution and number were assessed. RESULTS: The WR mice had a higher number and percent CD8 SLN lymphocytes, higher MMP, and lower Annexin V/PI SLN lymphocytes than controls. Regardless of training status, an acute bout of strenuous exercise decreased the total and phenotype specific (CD3, CD4, CD8) number of cells, MMP, and GSH levels immediately after exercise. CONCLUSION: WR in mice improved some aspects of cell viability in SLN lymphocytes compared with controls, but did not prevent the transient cell loss after acute treadmill exercise. Given the depletion in intracellular GSH levels, oxidative stress may account for the decline in SLN lymphocyte numbers following acute exercise. Loss of SLN lymphocytes may have consequences for ocular, oral, and upper respiratory tract health in some exercise participants and athletes during periods of overtraining.  相似文献   
100.
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