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   647篇
  免费   23篇
  国内免费   96篇
耳鼻咽喉   2篇
儿科学   35篇
妇产科学   30篇
基础医学   58篇
口腔科学   20篇
临床医学   107篇
内科学   168篇
皮肤病学   7篇
神经病学   19篇
特种医学   109篇
外科学   24篇
综合类   36篇
预防医学   27篇
眼科学   4篇
药学   91篇
肿瘤学   29篇
  2023年   3篇
  2022年   1篇
  2021年   7篇
  2020年   2篇
  2019年   7篇
  2018年   5篇
  2017年   4篇
  2016年   6篇
  2015年   5篇
  2014年   9篇
  2013年   22篇
  2012年   14篇
  2011年   16篇
  2010年   33篇
  2009年   28篇
  2008年   24篇
  2007年   65篇
  2006年   19篇
  2005年   28篇
  2004年   6篇
  2003年   11篇
  2002年   12篇
  2001年   20篇
  2000年   12篇
  1999年   9篇
  1998年   41篇
  1997年   39篇
  1996年   29篇
  1995年   29篇
  1994年   28篇
  1993年   38篇
  1992年   13篇
  1991年   10篇
  1990年   18篇
  1989年   32篇
  1988年   28篇
  1987年   15篇
  1986年   17篇
  1985年   14篇
  1984年   9篇
  1983年   3篇
  1982年   7篇
  1981年   4篇
  1980年   10篇
  1979年   2篇
  1978年   3篇
  1977年   7篇
  1976年   1篇
  1975年   1篇
排序方式: 共有766条查询结果,搜索用时 0 毫秒
61.
62.
The COVID-19 pandemic had a notable impact on the psychological well-being of a large part of the population, putting them at risk of developing depressive symptoms, different levels of anxiety disorders, and posttraumatic stress disorder (PTSD). One group considered to be at high risk are Nursing students; they were affected as learning strategies changed and clinical practices were cancelled. This study attempts to assess the psychological impact COVID-19 pandemic had on Nursing students and to explore the sociodemographic differences that can be risk factors for mental health disturbance. The psychological impact was evaluated using the Impact of Event Scale-Revised (IES-R) and Hospital Anxiety and Depression Scale (HADS). The study took place 4 months after the state of alarm was declared over in Spain. From a total sample of 304 Nursing students, 26.7%, 39.8%, and 15.5% showed PTSD, anxiety, and depression symptoms, respectively. Severe levels of psychological impact have been associated with being a female, a smoker, and feeling fear and stress. Having a relative test positive has been linked to lower anxiety levels while being afraid or stressed to higher anxiety levels. Being a female, co-habit with friends and feeling stress have been associated with higher depression levels.  相似文献   
63.

Purpose

To compare axial length (AL) growth curves in East Asian (EA) and non-EA emmetropes.

Methods

A meta-regression of 28 studies with emmetrope-specific AL data (measured with optical biometry) was performed. Emmetropia was defined as spherical equivalent refraction (SER) between −0.50 and +1.25 D, determined under cycloplegia if the mean age was ≤20 years. The AL growth curve (mean AL vs. mean age) was first fitted to the full dataset using a weighted nonlinear mixed-effects model, before refitting the model with ethnicity as a two-level grouping variable (EA vs. non-EA). Ethnic differences in growth curve parameters were tested using the Wald test.

Results

A total of 3331 EA and 1071 non-EA emmetropes (mean age: 6.5–23.1 years) were included. There was no evidence of an ethnic difference in either final AL (difference: 0.15 mm, 95% CI: −0.04 to 0.35 mm, p = 0.15) or initial AL, as represented by the amount that the final AL needed to be offset to obtain the y-intercept (difference: −2.77 mm, 95% CI: −10.97 to 5.44, p = 0.51). Likewise, AL growth rate (curve steepness) did not differ between ethnic groups (difference: 0.09, 95% CI: −0.13 to 0.31, p = 0.43). Collectively, AL growth rate decreased from 0.24 mm/year at 6 years of age to around 0.05 mm/year at 11 years of age, after which it dipped below the repeatability of optical biometry (±0.04 mm) and practically plateaued around 16 years of age (final AL: 23.60 mm).

Conclusions

EA and non-EA emmetropes have comparable AL growth curves.  相似文献   
64.
BACKGROUND: Growing interest is nowadays focused on the quality of life of elderly people who survive with chronic diseases. Coronary heart disease (CHD) is one of the most common diseases among the elderly and may have an unfavourable impact on the patient's emotional well-being. OBJECTIVES: We aimed to describe the prevalence of depression and the occurrence of depressive symptoms among elderly CHD patients, with a special emphasis on the relations between depression and the severity of CHD, and to find out the possible association between CHD and depression. METHODS: The study was carried out at the health centre of the municipality of Lieto, in south-west Finland. The study population consisted of 488 community-dwelling men and 708 women, over 64 years old, from among whom the participants with CHD (89 men and 73 women) were selected, and for whom 178 male and 146 female sex- and age- matched controls (free of CHD) were drawn from the population. CHD patients were selected on the basis of the presence of angina pectoris or a past myocardial infarction. Depressive symptoms were measured with the Zung Self-rating Depression Scale. Depression was described in relation to the severity of dyspnoea and chest pain among patients. The associations between depression and age, health, health behaviour, drugs, functional ability and social, psychosocial and environmental factors were analysed by logistic regression analyses. RESULTS: The prevalence of depression was 29% among male patients and 20% among female patients. Depression was significantly more common among male CHD patients than among male controls (P = 0.011). Among women, depression was not associated with CHD. Earlier, depression had gone undiagnosed among many CHD patients and controls, especially male patients. Among male CHD patients, depression was associated with more severe dyspnoea, but no similar association was found among female CHD patients. Among men the occurrence of CHD, physical disability, widowhood or divorce, and among women previous clinical depression, physical disability and the use of angiotensin-converting enzyme (ACE) inhibitors, were associated with depression. CONCLUSION: Depression is common among patients with CHD. It seems that CHD is not an independent factor in the aetiology of depression among the elderly. The association of CHD with depression among men is explained by the acute or chronic psychic stress caused by CHD. It may be that the more complicated the patient's CHD, the more probable is the presence of depression.   相似文献   
65.
The aim of this study was to determine the inter‐rater reliability between one expert‐nurse and four clinical‐nurses who were asked to clinically assess infection of chronic wounds by using the World Union of Wound Healing Societies (WUWHS) criteria. A quasi‐experimental design was used to collect the data. In comparison to phase 1 in which ‘open questions’ were asked, in phase 2 a pre‐printed form (checklist) was introduced. In both phases, 55 chronic wounds were clinically assessed. For each WUWHS criterion the inter‐rater reliability of signs and symptoms was expressed by Cohens Kappa (κ). A substantial agreement (κ ≥ 0·6) was considered as adequate. In both phases pocketing (p < 0·02), and erythema (p < 0·004) scored statistically significant results. Phase 2 showed higher inter‐rater agreements compared with phase 1 (three substantial agreements (easily bleeding/friable granulation tissue, delayed healing, increasing exudate), an almost perfect‐ and a perfect agreement for malodour and pain, respectively. According to the results it can be concluded that the clinical assessment of infection of chronic wounds may be better supported by a pre‐printed form than making use of an ‘open questions’ form. To provide this with a higher level of evidence, there is need for more well conducted studies.  相似文献   
66.
The first two chapters of Best practice for the care of patients with tuberculosis: a guide for low-income countries include an introduction and guidance regarding implementation of best practice. The background to how the guide was developed is significant, as it was developed in collaboration with nurses and other health workers working in the most challenging settings. It therefore provides realistic and practical guidance for best practice where patient loads are large and resources are stretched. Guidance regarding standard setting and clinical audit is an important part of enabling people to recognise the strengths that already exist in their practice and approach those areas that require change in a systematic and practical way. The guide itself consists of a series of standards covering different aspects of patient care, from the moment they seek health care with symptoms to their diagnosis to early stages of treatment, directly observed treatment, the continuation phase and transfer of treatment. There are also standards relating specifically to HIV testing and the care of patients co-infected with tuberculosis and HIV. The standards themselves will appear in full in the subsequent chapters of this series.  相似文献   
67.
高效液相色谱法测定消痰咳片的含量   总被引:2,自引:0,他引:2  
目的:采用反相色谱法同时测定消痰咳片中两种主要成分甲氧苄啶和磺胺体的含量。方法:以乙腈:0.1%H3PO4(15:85)为流动相,检测波长254nm,HPLC法测定含量。结果:试验表明,甲氧苄啶和磺胺林在0.8-8ug范围内呈良好的线性关系,回归方程分别为Y=-1127.1+110.2x(r=0.9994),Y=-1852.3 256.2x(r=0.9996),相对标准偏差分别为2.1%和0.8%。结论:该方法简便、准确、可靠。  相似文献   
68.
目的:考察5种注射剂盐酸林可霉素注射液,盐酸精氨酸注射液,注射用玻璃酸酶,肝素钠注射液和顺铂注射液的细菌内毒素检查法可行性。方法:中国药典细菌内毒素检查法。结果;除d外,其余原液及稀释液均于有干扰作用。结论:d的原液及a的20倍以上稀释液可用灵敏度为0.5EU/ml的鲎试剂作细菌内毒素检查,而b,c和e尚需进一步探讨。  相似文献   
69.
磁性明胶微球体内分布实验研究   总被引:11,自引:0,他引:11  
对磁性明胶微球进行了同位素标记。用γ-闪烁照相技术观察了磁性明胶微球在兔体内的分布。结果表明:靶部位的放射活性加磁场是未加磁场的15倍,而且施加磁场时间长和磁场强度大有利于磁性明胶微球定位于靶区。文中也介绍了自行设计的外加磁场装置。  相似文献   
70.
Patients with the syndrome of chronic daily headache often report migrainous symptoms and consequently are diagnosed as having a primary headache syndrome. We report two cases of idiopathic intracranial hypertension causing chronic daily headache with migrainous features in the absence of associated papilledema.  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