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   989篇
  免费   40篇
耳鼻咽喉   13篇
儿科学   13篇
妇产科学   57篇
基础医学   124篇
口腔科学   18篇
临床医学   75篇
内科学   226篇
皮肤病学   36篇
神经病学   95篇
特种医学   20篇
外科学   112篇
综合类   6篇
预防医学   55篇
眼科学   5篇
药学   46篇
肿瘤学   128篇
  2023年   18篇
  2022年   15篇
  2021年   36篇
  2020年   11篇
  2019年   24篇
  2018年   21篇
  2017年   23篇
  2016年   23篇
  2015年   26篇
  2014年   32篇
  2013年   40篇
  2012年   66篇
  2011年   74篇
  2010年   35篇
  2009年   37篇
  2008年   63篇
  2007年   54篇
  2006年   61篇
  2005年   61篇
  2004年   63篇
  2003年   44篇
  2002年   39篇
  2001年   7篇
  2000年   13篇
  1999年   18篇
  1998年   12篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1994年   2篇
  1993年   4篇
  1992年   7篇
  1991年   4篇
  1990年   4篇
  1989年   7篇
  1988年   8篇
  1987年   12篇
  1986年   6篇
  1985年   2篇
  1984年   8篇
  1983年   5篇
  1979年   3篇
  1978年   6篇
  1976年   2篇
  1975年   4篇
  1973年   5篇
  1972年   6篇
  1971年   1篇
  1966年   1篇
  1965年   1篇
排序方式: 共有1029条查询结果,搜索用时 31 毫秒
31.

Background

Wearing a pollution mask is an effective, practical, and economic way to prevent the inhalation of dangerous particulate matter (PM). However, it is not uncommon to observe negligence in adopting such behaviour, and this especially among young segments of the population. Using the Theory of Planned Behaviour (TPB) as conceptual framework, this study explores the role of socio-cognitive factors that affect the decision of wearing a pollution mask in the context of young educated people. This is done by selecting a sample of college students in urban China, a country that has seen air quality as one of the major challenges in the last decades. While young urban college students might be expected to be receptive to standard attempts to be influenced through reason-based cognitive stimuli, it is often found that this is not the case. The empirical analysis was articulated it in two steps. Structural Equation Modelling (SEM) was first used to examine the relationships among the conceptual constructs derived from the TPB conceptual model, and second Step-Wise Ordinary Least Squares Regressions (SWOLS) were employed to observe the partial effect played by each item on the decision to wear a mask.

Results

Results show that, while reason-based stimuli play a role, attitude, social norm, and self-efficacy were the most important predictors of the behavioural intention (p?<?0.01). The role of past behaviour was also acknowledged as strongly associated with the dependent variable (p?<?0.01). Overall, the likelihood of wearing a pollution mask increases with the importance of others socio-cognitive and psychological factors, which could help understand behavioural biases, and explain the relative role of several mechanisms behind the decision to wear a mask.

Conclusions

While tackling pollution requires multiple and synergic approaches, encouraging self-prevention using pollution mask is a simple and effective action, implementable at negligible costs. Resistance among younger, well-educated cohorts to wear masks can be overcome by stressing the social desirability of action and the sense of empowerment derived from its usage. This study has the potential to inform policies aimed at changing suboptimal behavioural attitudes by identifying triggers for change, and it could serve in improving the tailoring of health promotion messages aimed at nudging healthy behaviour.
  相似文献   
32.
International Urology and Nephrology - Free calcium is the gold standard for diagnosis of calcium disorders, although calcium assessment is routinely performed by albumin-adjusted calcium. Our...  相似文献   
33.
OBJECTIVE: To determine whether neurophysiologic findings correlate to clinical respiratory signs or spirometric abnormalities in patients with hereditary motor and sensory neuropathy type 1 (Charcot-Marie-Tooth disease). DESIGN: A total of 11 patients with hereditary motor and sensory neuropathy type 1A, genetically identified, (age range, 10-58 yr) were included and studied by physical pulmonary examination, chest radiography, respiratory function tests, and bilateral transcutaneous phrenic nerve conduction. RESULTS: No patient complained of respiratory symptoms or revealed abnormal spirometric or maximal respiratory pressure data, despite a phrenic nerve conduction significantly slower (P < 0.0001; median conduction time, 18.6 msec; 95th percentile, 31.97 msec) than that recorded in the control group of healthy subjects (median, 6.05 msec; 95th percentile, 8.82 msec); the amplitudes of compound muscle action potentials were not statistically different from the controls. CONCLUSIONS: Our study confirms a dramatic phrenic nerve involvement in absence of clinical and laboratory evidence of diaphragmatic weakness; further studies and an adequate follow-up are necessary to discover whether the disease progress might encompass respiratory dysfunction at later stages.  相似文献   
34.
Cough is an airway defensive reflex substantially consisting in a modified respiratory act. Transection experiments have shown that the fundamental structures responsible for this reflex are located within the medulla oblongata. Electrical stimulation applied to the medulla failed to provide convincing evidence of a cough centre distinct from the brainstem respiratory network. In fact, electrical stimuli affect not only neuronal somata, but also intramedullary cough-related pathways. Studies on the behaviour of medullary respiratory neurones have led to the conclusion that the same respiratory neurones involved in the generation of the eupnoeic pattern of breathing also participate in the production of the cough motor pattern. These findings support the existence of multifunctional neural networks in the mammal brainstem. B?tzinger complex expiratory neurones with augmenting discharge patterns have been suggested to convey an excitatory drive to the expiratory bulbospinal neurones of the caudal ventral respiratory group and, hence, to expiratory motoneurones. The excitatory drive to caudal medullary expiratory neurones is mediated by ionotropic glutamate receptors. Recent lines of evidence indicate that the B?tzinger complex and the caudal ventral respiratory group have a crucial role in determining both the inspiratory and the expiratory components of the cough motor pattern.  相似文献   
35.
Objectives

The aim of this prospective comparative clinical study was to evaluate the effect of oral anticoagulants on peri- and post-operative bleeding during simple single tooth extractions, comparing patients in treatment with vitamin K antagonists (VKAs) and patients assuming direct oral anticoagulants (DOACs).

Materials and methods

Patients under oral anticoagulant therapy needing dental extraction were eligible for entering the study; patients were enrolled following inclusion and exclusion criteria and divided into VKAs and DOAC group according to the anticoagulation therapy. Included patients underwent a simple single dental extraction with elevators and forceps with a maximum surgical time of 15 minutes, without anticoagulation therapy discontinuation. All participants were assessed pre-operatively, during surgery, 30 min minutes and 7 days after surgery. Biological complications were registered and post-extraction bleeding was clinically defined according to Iwabuchi classification. Parametric and non-parametric tests were used to evaluate the variables between the groups.

Results

Sixty-five patients per group were enrolled and 130 teeth were extracted. The two groups were comparable for pre-, peri-, and post-operative variables. Only 1 patient of DOAC group and 2 patients for VKA group needed medical evaluation for post-extractive bleeding. No statistically significant difference resulted in post-operative bleeding events between the groups (p = 0.425).

Conclusions

DOAC and VKA patients showed the same incidence of bleeding complications after simple single tooth extraction. Bleeding events were not statistically significant and not clinically relevant.

Clinical relevance

Patients assuming DOACs can be treated similarly to patients in VKAs therapy with INR index between 2 and 3. Non-ceasing of DOAC therapy seems to be appropriate for simple single dental extractions.

  相似文献   
36.
Several factors affect the levels of parathyroid hormone (PTH) in hip-fracture patients. We hypothesized that a panel of easily assessable determinants could account for both a substantial proportion of PTH variance and the occurrence of secondary hyperparathyroidism. We evaluated 909 of 981 hip-fracture inpatients admitted consecutively to our Rehabilitation division. In each patient we assessed PTH, 25-hydroxyvitamin D, albumin-adjusted total calcium, phosphate, magnesium, and creatinine on a fasting blood sample 21.3 ± 6.1 (mean ± SD) days after fracture occurrence. Glomerular filtration rate (GFR) was estimated by the 4-variable Modification of Diet in Renal Disease Study equation. Functional level was assessed using the Barthel index. On multivariate analysis, six factors (phosphate, albumin-adjusted total calcium, estimated GFR (eGFR), 25-hydroxyvitamin D, age, and magnesium) were significantly associated with PTH levels. Overall, the panel of variables accounted for 23.7 % of PTH variance. Among the 909 patients, 304 (33.4 %) had PTH levels exceeding the normal range. Six factors (phosphate, albumin-adjusted total calcium, eGFR, 25-hydroxyvitamin D, age, and Barthel index scores) were significantly associated with the category of PTH level (either normal or elevated). The model correctly classified 70.4 % of cases. For the optimal cut-off point, sensitivity was 80 % and specificity was 61 %. Data shows that six factors were significantly associated with PTH levels in hip-fracture inpatients. However, the six factors accounted for only 23.7 % of PTH variance and the presence or absence of secondary hyperparathyroidism was correctly categorized in a modest proportion of cases. We conclude that more knowledge is needed on the factors affecting PTH levels after hip fracture.  相似文献   
37.
38.
Here, we used a murine model to describe and compare the pathogenic potential of the Argentinean equid herpesvirus 1 (EHV-1) AR8 strain with the Japanese HH1 reference strain. In AR8-inoculated animals, clinical signs began earlier, but the viremic phase was shorter. Virus isolation and DNA detection in the lungs, liver and spleen were positive for both strains at different times postinfection (pi). Infection foci produced by both strains were immunohistochemically detected in lungs from day 1 to day 4 pi. We conclude that whichever EHV-1 strain is selected to experimentally reproduce the disease, it needs appropriate standardization in order to provide valid conclusions.  相似文献   
39.
40.
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