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   827篇
  免费   53篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   31篇
妇产科学   44篇
基础医学   122篇
口腔科学   26篇
临床医学   86篇
内科学   128篇
皮肤病学   5篇
神经病学   38篇
特种医学   20篇
外科学   85篇
综合类   5篇
预防医学   85篇
眼科学   3篇
药学   70篇
中国医学   1篇
肿瘤学   130篇
  2022年   6篇
  2021年   14篇
  2020年   17篇
  2019年   13篇
  2018年   18篇
  2017年   14篇
  2016年   8篇
  2015年   26篇
  2014年   20篇
  2013年   37篇
  2012年   40篇
  2011年   46篇
  2010年   35篇
  2009年   35篇
  2008年   44篇
  2007年   46篇
  2006年   51篇
  2005年   38篇
  2004年   49篇
  2003年   39篇
  2002年   37篇
  2001年   19篇
  2000年   40篇
  1999年   29篇
  1998年   18篇
  1997年   14篇
  1996年   8篇
  1995年   4篇
  1994年   6篇
  1993年   6篇
  1992年   15篇
  1991年   11篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   7篇
  1986年   5篇
  1985年   3篇
  1984年   4篇
  1983年   3篇
  1981年   2篇
  1980年   2篇
  1979年   4篇
  1978年   2篇
  1977年   4篇
  1976年   3篇
  1974年   8篇
  1973年   3篇
  1972年   6篇
  1968年   2篇
排序方式: 共有881条查询结果,搜索用时 15 毫秒
11.
Direct oral anticoagulants provide an alternative to vitamin K antagonists for the anticoagulation therapy in atrial fibrillation (AF). The availability of several treatment options with different attributes makes shared decision‐making appropriate for the choice of anticoagulation therapy. The aim of this study was to understand how physicians choose an oral anticoagulant (OAC) for patients with AF and how physicians view patients’ participation in this decision. Semi‐structured interviews with 17 Finnish physicians (eight general practitioners and nine specialists) working in the public sector were conducted. An interview guide on experience, prescribing and opinions about oral anticoagulants was developed based on previous literature. The data were thematically analysed using deductive and inductive approaches. Based on the interviews, patient's opinion was the most influential factor in decision‐making when there were no clinical factors limiting the choice between OACs. Of patient's preferences, the most important was the attitude towards co‐payments of OACs. Patients’ opinions on monitoring of treatment, dosing and antidote availability were also mentioned by the interviewees. The choice of an OAC in AF was patient‐centred as all interviewees expressed that patient's opinion affects the choice.  相似文献   
12.
13.
Premature adrenarche (PA) refers to an earlier than normal increase in adrenocortical androgen production. The pathogenesis of PA remains largely unknown. We hypothesized that common polymorphisms at P450 oxidoreductase (POR), steroid sulfotransferase (SULT2A1), or 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1) genes could contribute to the polygenic pathogenesis of PA. We performed a case–control study on the polymorphisms rs1057868 at POR, rs182420 at SULT2A1, and rs12086634 at HSD11B1. The study cohort comprised 73 prepubertal children with PA (defined by clinical signs) and 97 age- and gender-matched healthy controls from a Finnish Caucasian population. Genotype distributions and clinical and metabolic phenotypes were determined. The genotype distributions of the polymorphisms were similar between the study groups. No variant was associated with alterations in serum adrenal steroid concentrations. The minor C variant at SULT2A1 was associated with higher serum sex hormone binding globulin (SHBG) concentrations (T/T, n = 64 vs T/C&;C/C, n = 33; mean 94 vs 116 nmol/L; P = .001) and a trend for lower dehydroepiandrosterone sulfate/dehydroepiandrosterone ratios in the controls (P = .06), and with higher plasma total cholesterol concentrations in the PA subjects (T/T, n = 42 vs T/C&;C/C, n = 31; 4.0 vs 4.6 mmol/L; P < .001). The minor G variant at HSD11B1 was associated with lower plasma triglyceride concentration in the controls (T/T, n = 65 vs T/G&;G/G, n = 32; 0.61 vs 0.49 mmol/L; P = .013). Common polymorphisms at POR, SULT2A1 or HSD11B1 were not associated with PA in a Finnish Caucasian population.  相似文献   
14.
INTRODUCTION: We investigated those psychiatric patients whose reason for seeking medical help was primarily a physical condition. Our objectives were to analyse to what extent they suffered from seasonal variation in mood and behaviour during winter, and to examine whether these patients were evenly distributed between the categories of the ICD-10 Classification of Mental and Behavioural Disorders (ICD-10) by their primary diagnosis of mental disorder. METHOD: Patients attending the psychiatric services of a consultation liaison unit were interviewed for diagnosis, and were asked to fill in a questionnaire on seasonal variation in mood and behaviour. RESULTS: Our results suggest that there are many patients fulfilling the criteria based on the Seasonal Pattern Assessment uestionnaire (SPA) for seasonal affective disorder (SAD) or for subsyndromal SAD, not only in the ICD-10 diagnosis category of mood (affective) disorders but also in other disorder categories. CONCLUSION: This observation is of importance to hospital and private clinicians, as it emphasizes the need to assess the clinical picture in detail and to consider treatment alternatives for patients presenting with mental disorder with a seasonal pattern. (Int J Psych Clin Pract 2000; 4:151-154)  相似文献   
15.
16.
In this study, positron emission tomography (PET) imaging with a radioligand to adenosine A2A receptors (A2AR)—a potent regulator of inflammation—was used to gain insight into the molecular alterations in normal-appearing white matter (NAWM) and gray matter (GM) in secondary progressive multiple sclerosis (SPMS). Normal-appearing white matter and GM, despite seeming normal in conventional mangnetic resonance imaging (MRI), are important loci of widespread inflammation, neuronal damage, and source of progressive disability in multiple sclerosis (MS). Dynamic PET imaging using A2AR-specific [11C]TMSX and brain MRI with diffusion tensor imaging were performed to eight SPMS patients and seven healthy controls. Distribution volumes (VT) of [11C]TMSX were analyzed from 13 regions of interest using Logan plot with arterial plasma input. The SPMS patients had significantly increased [11C]TMSX-VT in NAWM compared with controls (mean (s.d.): 0.55 (±0.08) vs. 0.45 (±0.05); P=0.036). Both the increased VT and the decreased fractional anisotropy (FA) in NAWM were associated with higher expanded disability status scale (EDSS) scores (P=0.030 and P=0.012, respectively), whereas the T2-lesion load of SPMS patients did not correlate with EDSS. This study shows, that A2ARs are increased in the brain of SPMS patients, and that [11C]TMSX-PET provides a novel approach to learn about central nervous system pathology in SPMS in vivo.  相似文献   
17.
Objectives:The purpose of this study was to design, validate, and optimize internally standardized real-time quantitative RT-PCR assays and to identify and avoid problems with assay reliability and examine the impact of an exogenous internal standard.Design and methods:The model system consisted of internally standardized quantitative real-time RT-PCR assays specific for PSA and hK2 mRNA based on time-resolved fluorometric detection of lanthanide chelates.Results:Reproducibility was best when large copy numbers (> 5000 per milliliter blood) were analyzed. Addition of an exogenous target-mimicking internal standard had no significant effect on the reproducibility of the method, but increased the calculated copy numbers by an average of 2-fold.Conclusions:We developed an internally standardized, specific and reproducible real-time RT-PCR analysis method for PSA and hK2 mRNA in circulating cells in the bloodstream. Both PSA and hK2 assays are sufficiently sensitive to detect two LNCaP cells per milliliter whole blood.  相似文献   
18.
The change in augmentation index following salbutamol inhalation has been applied to evaluate endothelial function. We examined the contribution of salbutamol‐induced increase in heart rate to the observed decrease in augmentation index. Haemodynamics were recorded using whole‐body impedance cardiography and continuous pulse wave analysis from tonometric radial blood pressure. All subjects (n = 335, mean age 46, body mass index 26, 48% men) were without medications with cardiovascular influences. The effects of salbutamol inhalation (0.4 mg) versus the endothelium‐independent agent nitroglycerin resoriblet (0.25 mg) were examined during passive head‐up tilt, as the haemodynamic influences of these compounds depend on body position. Salbutamol decreased augmentation index by ~3‐4% units in supine and upright positions. Although salbutamol moderately increased cardiac index (+4.5%) and decreased systemic vascular resistance (?8.5%), the significant haemodynamic explanatory factors for decreased augmentation index in multivariate analysis were increased supine heart rate, and increased upright heart rate and decreased ejection duration (< 0.001 for all, r= 0.36–0.37). Sublingual nitroglycerin decreased supine and upright augmentation index by ~15% units and ~23% units, respectively. The haemodynamic explanatory factors for these changes in multivariate analysis were increased heart rate, reduced ejection duration and reduced systemic vascular resistance ( 0.021 for all, r2 = 0.22–0.34). In conclusion, the lowering influence of salbutamol on augmentation index may be largely explained by increased heart rate, suggesting that this effect may not predominantly reflect endothelial function.  相似文献   
19.
OBJECTIVE--To study the efficiency of a stiff collar in restricting the instability of anterior atlantoaxial subluxation (AAS). METHODS--Twenty two successive patients with an unstable AAS were studied. Lateral view radiographs were taken of the cervical spine in flexion, extension, and neutral positions without a collar, and in full flexion with a custom made stiff collar. RESULTS--The collar restricted more than 30% of the maximal instability of the AAS in 50% of the patients. These patients had significantly shorter atlantoaxial distance in the neutral position than those in whom the collar was not able to restrict the instability. CONCLUSION--A stiff collar can restrict the atlantoaxial instability in selected rheumatic patients with an unstable AAS. Lateral view radiographs of the cervical spine in a neutral position can be used to identify the patients whom the collar will benefit.  相似文献   
20.
In February 1999, an outbreak of listeriosis caused by Listeria monocytogenes serotype 3a occurred in Finland. All isolates were identical. The outbreak strain was first isolated in 1997 in dairy butter. This dairy began delivery to a tertiary care hospital (TCH) in June 1998. From June 1998 to April 1999, 25 case patients were identified (20 with sepsis, 4 with meningitis, and 1 with abscess; 6 patients died). Patients with the outbreak strain were more likely to have been admitted to the TCH than were patients with other strains of L. monocytogenes (60% vs. 8%; odds ratio, 17.3; 95% confidence interval, 2.8-136.8). Case patients admitted to the TCH had been hospitalized longer before cultures tested positive than had matched controls (median, 31 vs. 10 days; P=.008). An investigation found the outbreak strain in packaged butter served at the TCH and at the source dairy. Recall of the product ended the outbreak.  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