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   4646篇
  免费   272篇
  国内免费   28篇
耳鼻咽喉   48篇
儿科学   101篇
妇产科学   88篇
基础医学   907篇
口腔科学   102篇
临床医学   346篇
内科学   1017篇
皮肤病学   104篇
神经病学   333篇
特种医学   114篇
外科学   684篇
综合类   21篇
一般理论   3篇
预防医学   261篇
眼科学   160篇
药学   323篇
中国医学   10篇
肿瘤学   324篇
  2023年   48篇
  2022年   139篇
  2021年   182篇
  2020年   104篇
  2019年   121篇
  2018年   149篇
  2017年   103篇
  2016年   109篇
  2015年   146篇
  2014年   154篇
  2013年   182篇
  2012年   280篇
  2011年   271篇
  2010年   184篇
  2009年   138篇
  2008年   270篇
  2007年   249篇
  2006年   237篇
  2005年   243篇
  2004年   205篇
  2003年   194篇
  2002年   163篇
  2001年   48篇
  2000年   40篇
  1999年   50篇
  1998年   39篇
  1997年   35篇
  1996年   26篇
  1995年   21篇
  1992年   37篇
  1991年   37篇
  1990年   47篇
  1989年   56篇
  1988年   42篇
  1987年   58篇
  1986年   37篇
  1985年   57篇
  1984年   33篇
  1983年   23篇
  1979年   26篇
  1978年   25篇
  1976年   24篇
  1975年   26篇
  1973年   34篇
  1972年   18篇
  1971年   29篇
  1970年   25篇
  1969年   21篇
  1967年   24篇
  1966年   19篇
排序方式: 共有4946条查询结果,搜索用时 18 毫秒
51.
52.
STUDY OBJECTIVES: Following the development of the Caribbean Guidelines for Asthma Care, we examined the utilization of inhaled medications in asthmatic patients in Trinidad, West Indies. SETTING: Chest Clinic, Ministry of Health, Trinidad. PARTICIPANTS: Physician-diagnosed asthmatic patients who attended the Chest Clinic between July 1998 and August 2000. MEASUREMENTS AND RESULTS: A consecutive sample of patients who were > 7 years of age (n = 402) was interviewed about compliance with, understanding of, and use of inhaler medication. The inhaler technique of these patients was directly observed. Inhaled steroid therapy was prescribed in 83% of patients but were prescribed the least in elderly patients (63%) and children (62%). Salbutamol was prescribed in 98% of patients, and ipratropium and sodium cromoglycate were selectively prescribed in elderly men and children, respectively. Only 33% of patients used the inhaler correctly, and children and the elderly were the least efficient in its use. The use of a spacer device was advised in 19% of patients, including only 6% of the elderly patients. Explanations for different inhaler therapies were given to 62% of patients, and 53% of patients could describe these reasons. The reported 40% noncompliance rate among patients in the sample was primarily a result of long waiting periods at the pharmacy (58%) and the personal cost incurred on purchasing the medication (52%). CONCLUSIONS: Educating patients, with a focus on children and the elderly, in inhaler techniques and reinforcing understanding of asthma medications can improve asthma management in Trinidad. Asthma caregivers in the Caribbean should ensure the appropriate dissemination of the guidelines and should outline strategies for their implementation.  相似文献   
53.
Seasonal influenza vaccination elicits a diminished adaptive immune response in the elderly, and the mechanisms of immunosenescence are not fully understood. Using Ig-Seq, we found a marked increase with age in the prevalence of cross-reactive (CR) serum antibodies that recognize both the H1N1 (vaccine-H1) and H3N2 (vaccine-H3) components of an egg-produced split influenza vaccine. CR antibodies accounted for 73% ± 18% of the serum vaccine responses in a cohort of elderly donors, 65% ± 15% in late middle-aged donors, and only 13% ± 5% in persons under 35 years of age. The antibody response to non-HA antigens was boosted by vaccination. Recombinant expression of 19 vaccine-H1+H3 CR serum monoclonal antibodies (s-mAbs) revealed that they predominantly bound to non-HA influenza proteins. A sizable fraction of vaccine-H1+H3 CR s-mAbs recognized with high affinity the sulfated glycans, in particular sulfated type 2 N-acetyllactosamine (Galβ1-4GalNAcβ), which is found on egg-produced proteins and thus unlikely to contribute to protection against influenza infection in humans. Antibodies against sulfated glycans in egg-produced vaccine had been identified in animals but were not previously characterized in humans. Collectively, our results provide a quantitative basis for how repeated exposure to split influenza vaccine correlates with unintended focusing of serum antibody responses to non-HA antigens that may result in suboptimal immunity against influenza.  相似文献   
54.
Recently, it has been shown that increased level of LDL-containing circulating immune complexes (LDL-CIC) possess high diagnostic significance in clinically manifested atherosclerosis, but little is known about its diagnostic and prognostic significance in early atherosclerosis. Two-years prospective study was performed in 98 asymptomatic men aged 40–74. The rate of atherosclerosis progression was estimated by high-resolution B-mode ultrasonography as the increase in intima-media thickness (IMT) of common carotid arteries. The patients with elevated baseline levels of LDL-CIC were characterized by significantly higher levels of total and LDL cholesterol as well as significantly increased mean IMT of common carotid arteries. Among all baseline lipid parameters, only LDL-CIC and LDL cholesterol were contingent with the extent of early carotid atherosclerosis (p?=?0.042 and p?=?0.049, respectively) and had the highest levels of relative risk and odds ratio. During the follow up, significant IMT increase was registered in 53.1 % (n?=?52) patients, IMT significant reduction was observed in 21.4 % (n?=?21) patients. The increased levels of LDL-CIC, total serum cholesterol and LDL cholesterol had similar prognostic significance with the respect of atherosclerosis progression. The normal level of LDL-CIC (below than 16.0 μg/ml) was the only lipid parameter that predicted the absence of carotid atherosclerosis progression for two following years at prognostic value of 78.3 %. The results of the study allow assuming that LDL-CIC level may be employed not only as a marker of early atherosclerosis, but also has a sufficient prognostic value for clinical implications.  相似文献   
55.
Objective: We report two cases of atypical femoral fracture (AFF) in patients with cancer.Patients: Two patients, a 53-year-old woman with breast cancer and a 77-year-old man with prostate cancer, could not walk after being injured in a fall. They used bone-modifying agents (BMA) for the prevention of bone metastasis for three and four years, respectively.Results: Intramedullary nails were placed to fix the femoral fractures in each patient. Neither of them had pathological metastatic femoral fractures based on fracture site specimens; however, severe suppression of bone turnover at the fracture site was suspected. Both patients could ambulate with a T-cane and were free of hip pain after surgery. Radiographs showed no callus formation at the fracture site.Conclusion: Based on the two cases of AFF in patients with cancer related to BMA use, we should consider that the incidence of AFF may be associated with long-term BMA use.  相似文献   
56.
Biomedical Engineering - A device for converting skin temperature oscillations into oscillations of blood filling of peripheral vessels has been developed. The operation of the device is based on...  相似文献   
57.
Journal of Muscle Research and Cell Motility - Two single mutations, R694N and E45Q, were introduced in the beta isoform of human cardiac myosin to remove permanent salt bridges E45:R694 and...  相似文献   
58.
The liquid and lyophilized blood plasma of patients with benign or malignant thyroid nodules and healthy individuals were studied by terahertz (THz) time-domain spectroscopy and machine learning. The blood plasma samples from malignant nodule patients were shown to have higher absorption. The glucose concentration and miRNA-146b level were correlated with the sample’s absorption at 1 THz. A two-stage ensemble algorithm was proposed for the THz spectra analysis. The first stage was based on the Support Vector Machine with a linear kernel to separate healthy and thyroid nodule participants. The second stage included additional data preprocessing by Ornstein-Uhlenbeck kernel Principal Component Analysis to separate benign and malignant thyroid nodule participants. Thus, the distinction of malignant and benign thyroid nodule patients through their lyophilized blood plasma analysis by terahertz time-domain spectroscopy and machine learning was demonstrated.  相似文献   
59.
60.
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