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   60177篇
  免费   4176篇
  国内免费   1148篇
耳鼻咽喉   970篇
儿科学   2126篇
妇产科学   917篇
基础医学   7011篇
口腔科学   974篇
临床医学   4482篇
内科学   10635篇
皮肤病学   1104篇
神经病学   14249篇
特种医学   1394篇
外国民族医学   10篇
外科学   5342篇
综合类   3405篇
一般理论   4篇
预防医学   3297篇
眼科学   1133篇
药学   4507篇
  13篇
中国医学   1999篇
肿瘤学   1929篇
  2023年   1145篇
  2022年   1466篇
  2021年   2799篇
  2020年   2882篇
  2019年   3490篇
  2018年   3253篇
  2017年   2817篇
  2016年   2053篇
  2015年   2078篇
  2014年   4595篇
  2013年   6005篇
  2012年   3641篇
  2011年   3677篇
  2010年   2824篇
  2009年   2658篇
  2008年   2464篇
  2007年   1967篇
  2006年   1593篇
  2005年   1315篇
  2004年   1365篇
  2003年   1153篇
  2002年   894篇
  2001年   731篇
  2000年   715篇
  1999年   529篇
  1998年   352篇
  1997年   366篇
  1996年   249篇
  1995年   286篇
  1994年   284篇
  1993年   253篇
  1992年   196篇
  1991年   189篇
  1990年   171篇
  1989年   140篇
  1988年   123篇
  1987年   101篇
  1985年   608篇
  1984年   646篇
  1983年   411篇
  1982年   494篇
  1981年   431篇
  1980年   350篇
  1979年   337篇
  1978年   279篇
  1977年   217篇
  1976年   215篇
  1975年   235篇
  1974年   170篇
  1973年   175篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The aim of this review was to investigate the types and rates of vascular lesions occurring in cases of completed hanging and near-hanging, defined in literature.In the literature to date, 6 specific types of vascular injuries have been defined in cases of death as a result of hanging. These are Amussat's sign, Etienne Martin's sign, Dominguez-Paez sign, Friedberg-Lesser sign, Ziemke-Otto's sign, and Lupascu sign.As a result of this study, it was determined that the most defined finding was the Amussat sign, and it was concluded that the other findings were not sufficiently recognized.Likewise, considering that the proportional differences are due to the differences in the rates of autopsy practice and autopsy protocols between countries, it can be suggested that international joint autopsy protocols should be developed at the meetings in which national professional associations participate.  相似文献   
3.
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations.  相似文献   
4.
Aim of the workTo evaluate hematologic parameters in patients with primary Sjögren's syndrome (PSS) and their association with disease activity.Patients and methodsSixty-five PSS patients and 65 age and sex matched control were studied. Neutrophil to lymphocyte ratio (NLR), mean platelet volume (MPV), red blood cells distribution width (RDW), platelet to lymphocyte ratio (PLR) and platelet count were evaluated. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured. The European league against rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI) was assessed.ResultsThe mean age of patients was 47.8 ± 12.1 years and disease duration 5.71 ± 1.2 years and they were 63 females and 2 males. The mean ESSDAI was 6.4 ± 7.9 (3–25). 11 had neurological involvement. 92.3% of patients received low-dose prednisolone (<10 mg/day) and hydroxychloroquine (HCQ). The mean NLR (1.83 ± 0.8), PLR (131.9 ± 32.5) and MPV (8.82 ± 1.4) in patients was significantly higher than in control (NLR 1.57 ± 0.56, PLR 109.9 ± 24.7 and MPV 7.71 ± 1.3; p = 0.036, p < 0.001 and p < 0.001 respectively). The RDW tended to be higher in patients (13 ± 1.56) compared to control (12.83 ± 1.13) (p = 0.46). There was a significant correlation between ESSDAI with NLR (r = 0.29, p = 0.02), RDW (r = 0.37, p = 0.002), ESR (r = 0.32, p = 0.01) and CRP (r = 0.33, p = 0.007) and between MPV with CRP (r = 0.27, p = 0.03) and between RDW and ESR (r = 0.36, p = 0.003).On regression analysis, NLR and RDW were significant predictors of disease activity (p = 0.01 and p = 0.02 respectively).ConclusionThe MPV, PLR and NLR, were significantly increased in PSS. NLR and RDW can be used as indicators of disease activity.  相似文献   
5.
目的采用竞争性等位基因特异性PCR(KASP)法、单碱基末端延伸(SNaPshot)法对载脂蛋白E(APOE)进行分型检测,并与Sanger测序法比较,以期获得更为高效、稳定、经济的中、高通量APOE分型手段。方法选取既往收集的覆盖全部6种常见APOE分型的阿尔茨海默病(AD)及轻度认知障碍(MCI)患者全血核酸样本48份,根据KASP法和SNaPshot法技术原理设计实验识别APOE 2个关键单核苷酸多态性(SNP)位点rs429358和rs7412,并对样本进行APOE分型检测。调整样本顺序重复检测以验证方法的稳定性和可重复性。扩大样本量,收集AD、MCI患者全血样本107份,采用上述两种方法进行APOE分型检测,Sanger测序法验证。结果采用KASP法和SNaPshot法对48份已知APOE分型样本的2次检测结果与原分型完全一致。进一步扩大样本量对107例样本进行分型检测,与Sanger测序法得到的结果完全一致。结论采用KASP法和SNaPshot法进行APOE分型检测具有快速、准确、结果直观等特点,应用中、高通量APOE分型检测相对于Sanger测序法效率更高、成本更低,具有一定推广应用价值。  相似文献   
6.
Even if the relationships between nutrition and inflammatory bowel disease (IBD) remain underexplored, the current literature is providing, day by day, much more evidence on the effects of various diets in both prevention and treatment of such illnesses. Wrong dietary habits, together with other environmental factors such as pollution, breastfeeding, smoke, and/or antibiotics, are among the theoretical pathogenetic causes of IBD, whose multifactorial aetiology has been already confirmed. While some of these risk factors are potentially reversible, some others cannot be avoided, and efficient treatments become necessary to prevent IBD spread or recurrence. Furthermore, the drugs currently available for treatment of such disease provide low-to-no effect against the symptoms, making the illnesses still strongly disabling. Whether nutrition and specific diets will prove to effectively interrupt the course of IBD has still to be clarified and, in this sense, further research concerning the applications of such dietary interventions is still needed.  相似文献   
7.
8.
9.
Heart failure (HF) has high event rates, mortality, and is challenging to manage in clinical practice. Clinical management is complicated by complex therapeutic strategies in a population with a high prevalence of comorbidity and general frailty. In the last four years, an abundance of research has become available to support multidisciplinary management of heart failure from within the hospital through to discharge and primary care as well as supporting diagnosis and comorbidity management. Within the hospital setting, recent evidence supports sacubitril-valsartan combination in frail, deteriorating or de novo patients with LVEF  40%. Furthermore, new strategies such as SGLT2 inhibitors and vericiguat provide further benefit for patients with decompensating HF. Studies with tafamidis report major clinical benefits specifically for patients with ATTR cardiac amyloidosis, a remaining underdiagnosed and undertreated disease. New evidence for medical interventions supports his bundle pacing to reduce QRS width and improve haemodynamics as well as ICD defibrillation for non-ischemic cardiomyopathy. The Mitraclip reduces hospitalisations and mortality in patients with symptomatic, secondary mitral regurgitation and ablation reduces mortality and hospitalisations in patients with paroxysmal and persistent atrial fibrillation. In end-stage HF, the 2018 French Heart Allocation policy should improve access to heart transplants for stable, ambulatory patients and, mechanical circulatory support should be considered to avoid deteriorating on the waiting list. In the community, new evidence supports that improving discharge education, treatment and patient support improves outcomes. The authors believe that this review fills the gap between the guidelines and clinical practice and provides practical recommendations to improve HF management.  相似文献   
10.
Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder. Cardiometabolic and genetic risk factors play an important role in the trajectory of AD. Cardiometabolic risk factors including diabetes, mid-life obesity, mid-life hypertension and elevated cholesterol have been linked with cognitive decline in AD subjects. These potential risk factors associated with cerebral metabolic changes which fuel AD pathogenesis have been suggested to be the reason for the disappointing clinical trial results. In appreciation of the risks involved, using search engines such as PubMed, Scopus, MEDLINE and Google Scholar, a relevant literature search on cardiometabolic and genetic risk factors in AD was conducted. We discuss the role of genetic as well as established cardiovascular risk factors in the neuropathology of AD. Moreover, we show new evidence of genetic interaction between several genes potentially involved in different pathways related to both neurodegenerative process and cardiovascular damage.  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