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   40113篇
  免费   2286篇
  国内免费   72篇
耳鼻咽喉   500篇
儿科学   1522篇
妇产科学   912篇
基础医学   5157篇
口腔科学   755篇
临床医学   3445篇
内科学   9367篇
皮肤病学   1278篇
神经病学   3593篇
特种医学   1030篇
外科学   5204篇
综合类   205篇
一般理论   40篇
预防医学   3862篇
眼科学   699篇
药学   2384篇
中国医学   118篇
肿瘤学   2400篇
  2023年   280篇
  2022年   402篇
  2021年   1087篇
  2020年   493篇
  2019年   1098篇
  2018年   1550篇
  2017年   908篇
  2016年   962篇
  2015年   958篇
  2014年   1191篇
  2013年   1738篇
  2012年   2819篇
  2011年   3023篇
  2010年   1625篇
  2009年   1259篇
  2008年   2443篇
  2007年   2567篇
  2006年   2497篇
  2005年   2436篇
  2004年   2228篇
  2003年   1988篇
  2002年   1954篇
  2001年   1100篇
  2000年   1324篇
  1999年   965篇
  1998年   248篇
  1997年   150篇
  1996年   161篇
  1995年   112篇
  1994年   118篇
  1993年   92篇
  1992年   366篇
  1991年   288篇
  1990年   281篇
  1989年   210篇
  1988年   163篇
  1987年   142篇
  1986年   150篇
  1985年   131篇
  1984年   101篇
  1983年   79篇
  1982年   53篇
  1981年   52篇
  1979年   49篇
  1977年   47篇
  1976年   44篇
  1974年   66篇
  1973年   63篇
  1972年   49篇
  1971年   46篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
IntroductionPeople with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population.MethodsParticipants included children, teenagers and adults with DS, 5 years of age or older (n = 302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DLCO), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards.ResultsFifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DLCO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO2) and respiratory rate (RR) showed deficient repeatability.ConclusionsIOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS.  相似文献   
22.
23.
24.
International Journal of Legal Medicine - Sex identification is a primary step in forensic analysis of skeletal remains. The accuracy of sex estimation methods greatly depends on the sexual...  相似文献   
25.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  相似文献   
26.
Introduction and objectivesBiological aerosols play a vital role in the interactions between the atmosphere, biosphere, climate and public health and fungal spores are a component with allergic importance.We constructed a database in Castile & Leon (Spain) and carry out molecular-level component-resolved diagnosis to complete the air quality study carried out since 2006 by our aerobiological network (RACYL) to aid clinical diagnosis and treatment.MethodsWe reviewed a database of 19,774 patients (adults and children) with allergic respiratory disease treated in our unit during the last 12 years. We also made a component-resolved diagnosis of the molecules involved in the pathology in a randomly selected population of 150 patients.ResultsThe dimeric glycoprotein Alt a1 from Alternaria is the most prevalent and most useful allergen in the diagnosis of patients with allergy to fungi in our area (94.4%), followed by enolase Alt a 6 (Alternaria), ribonuclease Asp f 1 of Aspergillus and mannitol dehydrogenase from Cla h 8 (Cladosporium).ConclusionsOur results have helped determine which spore molecules are most-closely associated with allergies. Molecular analysis will be useful to determine more accurate and useful immunotherapy in these patients.  相似文献   
27.
ObjectiveSeptic arthritis is a medical emergency and crystal-induced arthritis is a risk factor for its development. If both occur simultaneously, crystal-induced arthritis may mask the diagnosis of infection and delay antibiotic therapy.MethodRetrospective analysis of patients with coexistence of septic and crystal-induced arthritis. We included only patients with isolation of crystals in synovial fluid analysis and positive culture of synovial fluid and/or blood culture.ResultsA total of 25 patients (17 men and 8 women) with a mean age of 67 years. The most commonly affected joint was the knee. In synovial fluid cytological studies, the most frequently identified crystals were monosodium urate. Risk factors included diabetes and chronic renal failure. The most frequently isolated germs were methicillin-sensitive S. aureus (48%), methicillin-resistant S. aureus (12%) and Mycobacterium tuberculosis (12%). In all, 36% of subjects required surgical drainage (excluding those caused by M. tuberculosis). Clinical outcome was favorable in 56%, although intercurrent complications were usual (40%). Mortality was 8%.ConclusionsCoexistence of septic and crystal-induced arthritis represents a diagnostic challenge and requires a high index of suspicion. Gout was the most prevalent crystal-induced arthritis. S. aureus was the most commonly causative pathogen, with a high rate of methicillin-resistant S. aureus infection. If treated early, the outcome is usually favorable, making synovial fluid microbiological study imperative.  相似文献   
28.
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.  相似文献   
29.
Eye drops contain several ophthalmic medications which can produce allergic reactions. We report the case of a patient with contact dermatitis from neomycin and a probable fixed exanthema after parenteral administration of tobramycin who tolerated topical tobramycin and other aminoglycosides.  相似文献   
30.
OBJECTIVE: To assess antipsychotic medication in the treatment of schizophrenia, based on trial drop-out rates. METHOD: The studies included were randomised controlled trials that compared any of the four clinically best-established atypical antipsychotics (quetiapine, olanzapine, risperidone or clozapine) against either of two typical antipsychotics regarded as the gold standard (haloperidol or chlorpromazine). RESULTS: Meta-analysis indicated less risk of all-cause patient withdrawal from atypical medication trials where dosage was flexible, in both the short, relative risk (RR) 0.70 (95% CI 0.64-0.76), P<0.00001, and long term, RR 0.72 (0.65-0.80), P<0.00001. Similar results were observed for withdrawal due to adverse events, RR: 0.54 (0.41-0.72), P<0.0001. Nevertheless, the favourable effects of atypical medication disappeared in trials relying on fixed dosage. CONCLUSIONS: We detected a significant positive effect in terms of the outcome of treatment discontinuation for atypical versus typical medication, though only where the use of flexible rather than fixed doses (closer to an experimental control situation) was possible.  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