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   29355篇
  免费   2917篇
  国内免费   728篇
耳鼻咽喉   205篇
儿科学   683篇
妇产科学   633篇
基础医学   3282篇
口腔科学   445篇
临床医学   3283篇
内科学   4926篇
皮肤病学   208篇
神经病学   1792篇
特种医学   2251篇
外国民族医学   5篇
外科学   2808篇
综合类   2915篇
现状与发展   4篇
预防医学   1499篇
眼科学   295篇
药学   3790篇
  17篇
中国医学   892篇
肿瘤学   3067篇
  2024年   72篇
  2023年   547篇
  2022年   1079篇
  2021年   1691篇
  2020年   1375篇
  2019年   1323篇
  2018年   1274篇
  2017年   1219篇
  2016年   1178篇
  2015年   1312篇
  2014年   1946篇
  2013年   2076篇
  2012年   1550篇
  2011年   1648篇
  2010年   1273篇
  2009年   1297篇
  2008年   1275篇
  2007年   1272篇
  2006年   1000篇
  2005年   890篇
  2004年   794篇
  2003年   729篇
  2002年   599篇
  2001年   503篇
  2000年   432篇
  1999年   381篇
  1998年   364篇
  1997年   327篇
  1996年   290篇
  1995年   277篇
  1994年   274篇
  1993年   243篇
  1992年   251篇
  1991年   246篇
  1990年   258篇
  1989年   190篇
  1988年   194篇
  1987年   135篇
  1986年   145篇
  1985年   149篇
  1984年   153篇
  1983年   125篇
  1982年   135篇
  1981年   96篇
  1980年   74篇
  1979年   69篇
  1978年   64篇
  1977年   48篇
  1976年   43篇
  1975年   24篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The aim of this study was to carry out a retrospective multicentre study comparing the morphological outcome of 8 techniques used for the management of sagittal synostosis versus a large cohort of control patients. Computed tomographic (CT) images were obtained from children CT-scanned for non-craniosynostosis related events (n = 241) and SS patients at preoperative and postoperative follow-up stages (n = 101). No significant difference in morphological outcomes was observed between the techniques considered in this study. However, the majority of techniques showed a tendency for relapse. Further, the more invasive procedures at older ages seem to lead to larger intracranial volume compared to less invasive techniques at younger ages. This study can be a first step towards future multicentre studies, comparing surgical results and offering a possibility for objective benchmarking of outcomes between methods and centres.  相似文献   
2.
目的:探讨3D-CRT 低剂量区 V5体积的大小对非小细胞肺癌患者肺功能的影响。方法:收集我院肿瘤科2014年4月~2015年10月收治的46例首次行三维适形放射治疗且顺利完成治疗的非小细胞肺癌患者,对每例患者分别在治疗前以及治疗后的1、3个月进行肺功能检测,分析3D-CRT 低剂量区 V5体积的大小与肺功能变化之间的关系。结果:放疗后1个月的 FEV1%、FVC%值明显高于放疗前且差异均具有显著性。放疗后1个月、3个月的 DLCO%值明显低于放疗前,且放疗前的与放疗后3个月的差异具有显著性;V5≦45%、45%55%三组放疗前后的 FEV1%值和 FVC%值比较差异均不具有显著性。V5≦45%、45%55%三组放疗前后的 DLCO%值均呈逐渐下降趋势,且 V5>55%组的放疗前后 DLCO%值比较差异具有显著性。而 V5≦45%组和45%55%时,DLCO%值降低的趋势更加显著。  相似文献   
3.
Abstract

Background: Cerebral palsy (CP) is a common childhood disability. However, these individuals are now living longer lives, participating in adult roles, and seeking healthcare services. The transition from pediatric to adult healthcare for adolescents with CP is a challenging yet significant time. Adolescents experience several barriers during transition.

Objectives: To utilize the environmental and personal dimensions of the ICF model in order to explore barriers when transitioning to adulthood as well as discuss characteristics and physical therapy implications needed to succeed within transition.

Methods: Electronic searching of PubMed, CINAHL, ERIC, Scopus, ProQuest, and the Cochrane Library databases was concluded on January 9, 2019 for studies including transition between pediatric and adult healthcare in individuals diagnosed with CP. Two independent reviewers agreed upon inclusion, eligibility, and quality assessment of each study using the Mixed-Methods Appraisal Tool (MMAT).

Results: Seven studies were included in the systematic review. Results for each study were separated based on the personal and environmental contextual factors of the ICF model and solutions to the barriers were then discussed.

Conclusions: Research has provided proposed solutions to select barriers, however, other barriers have yet to be addressed. More research is needed to address these barriers and provide a model program that can be implemented within the healthcare systems to promote a successful transition for adolescents with CP from pediatric to adult services.  相似文献   
4.
5.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  相似文献   
6.
7.
8.
PurposeTo determine if cone-beam CT and digital subtraction angiography analysis of pelvic arterial anatomy has predictive value for radiation exposure and technical success of prostatic artery embolization (PAE).Materials and MethodsThis prospective, nonrandomized, single-center study included 104 consecutive patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia. Cone-beam CT was performed in 160/208 (76.9%) hemipelves to determine prostatic artery (PA) origin. Classification of pelvic arterial tortuosity was possible in 73/104 (70.2%) patients. Learning curves of 2 interventionalists who performed 86.5% of PAEs were analyzed.ResultsTortuosity of pelvic arteries was classified as mild in 25 (34.2%) patients median age 64 years, moderate in 40 (54.8%) patients median age 69 years, and severe in 8 (11.0%) patients median age 70 years (mild vs moderate, P = .002; mild vs severe, P = .019); median fluoroscopy times were 24, 36, and 46 minutes (P = .008, P = .023); median contrast volumes were 105, 122.5, and 142 mL (P = .029, P = .064); and bilateral PAE rates were 84.0%, 77.5%, and 62.5% (P = .437), respectively. PA origin from superior vesical artery was most frequent (27.5%) and showed higher dose area product (median 402.4 vs 218 Gy ∙ cm2, P = .033) and fluoroscopy time (median 42.5 vs 27 min, P = .01) compared with PA origin from obturator artery, which was least frequent. Interventionalist experience revealed significant impact on procedure times (median 159 vs 130 min, P = .006).ConclusionsTortuosity of pelvic arteries was more frequent in older patients and predicted worse technical outcomes of PAE. PA origin from obturator artery was associated with lower dose area product and fluoroscopy time, especially compared with PA origin from superior vesical artery. Interventionalist experience showed significant influence on technical outcome.  相似文献   
9.
10.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  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