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   8380篇
  免费   326篇
  国内免费   52篇
耳鼻咽喉   275篇
儿科学   351篇
妇产科学   401篇
基础医学   553篇
口腔科学   292篇
临床医学   732篇
内科学   2048篇
皮肤病学   121篇
神经病学   438篇
特种医学   334篇
外科学   2021篇
综合类   122篇
预防医学   175篇
眼科学   311篇
药学   319篇
中国医学   21篇
肿瘤学   244篇
  2024年   2篇
  2023年   68篇
  2022年   84篇
  2021年   244篇
  2020年   139篇
  2019年   168篇
  2018年   210篇
  2017年   174篇
  2016年   270篇
  2015年   321篇
  2014年   438篇
  2013年   513篇
  2012年   654篇
  2011年   598篇
  2010年   399篇
  2009年   400篇
  2008年   606篇
  2007年   675篇
  2006年   594篇
  2005年   606篇
  2004年   514篇
  2003年   433篇
  2002年   343篇
  2001年   54篇
  2000年   30篇
  1999年   28篇
  1998年   40篇
  1997年   28篇
  1996年   32篇
  1995年   22篇
  1994年   12篇
  1993年   9篇
  1992年   12篇
  1991年   7篇
  1990年   5篇
  1989年   3篇
  1988年   3篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1980年   2篇
  1974年   1篇
  1970年   1篇
  1966年   1篇
  1962年   2篇
排序方式: 共有8758条查询结果,搜索用时 109 毫秒
91.

Objectives

Systemic sclerosis (SSc) is a chronic, inflammatory, and autoimmune connective tissue disease that is associated with vascular lesions, and fibrosis of the skin and visceral organs. Cardiac complications may occur as a secondary effect of SSc as a result of pulmonary arterial hypertension and interstitial lung disease. The objective of this study was to assess whether the pulmonary pulse transit time (pPTT) could serve as a diagnostic marker for pulmonary arterial alterations in patients with SSc, prior to development of pulmonary hypertension.

Methods

Twenty-five SSc patients as a study group and 25 age- and sex-matched healthy volunteers for the control group were recruited to the study. Right ventricle function parameters, such as tricuspid annular plane systolic excursion (TAPSE), estimated pulmonary artery systolic pressure (ePASP), right ventricular dimensions, right ventricle fractional area changes, and myocardial perfusion index (MPI) were measured and calculated. Pulmonary pulse transit time was defined as the time interval between the R-wave peak in the ECG and the corresponding peak late systolic pulmonary vein flow velocity.

Results

Right ventricle myocardial performance index (RVMPI) and eSPAP were significantly higher in the SSc group than the controls (p?=?0.032, p?=?0.012, respectively). Pulmonary pulse transit time and TAPSE was shorter in the patients with SSc (p?=?0.006, p?=?0.015, respectively). In correlation analysis, pPTT was inversely correlated with RVMPI (r?=???0.435, p?=?0.003), eSPAP (r?=???0.434, p?=?0.003), and disease duration (r?=???0.595, p?=?0.003). Conversely, it positively correlated with TAPSE (r?=?0.345, p?=?0.022).

Conclusion

pPTT was found to be shorter in SSc patients. pPTT might serve as a surrogate marker of pulmonary hemodynamics in patients with SSc, even prior to the development of pulmonary hypertension.
  相似文献   
92.

Aim

Willis-Ekbom disease (RLS/WED) is common in chronic obstructive pulmonary disease (COPD). Patients with RLS/WED have poorer quality of sleep and more fatigue and depressive symptoms. The prevalence of RLS/WED in patients with COPD has been reported to vary between 29.1 and 36.8 %. However, during exacerbation, the prevalence can increase up to 54 %. These rates are higher than those seen in general population. We have not enough knowledge regarding the association between RLS and COPD. In this study, we aimed to determine the frequency of RLS in patients with stable COPD without comorbid conditions. In addition, we also aimed to determine possible related causative factors.

Method

We included 80 COPD patients without comorbid conditions who presented to our outpatient clinic between April 2013 and September 2013 for RLS/WED evaluation. Three cases that have polyneuropathy and one case that refused undergoing electromyography (EMG) examination were excluded from the study. Demographic data, P-A chest X-rays, pulmonary function tests (PFT), biochemical parameters (including hemogram), and dyspnea scales were evaluated for each patient. In addition, the RLS/WED rating scale and Epworth Sleep Scale (ESS) were applied. Further, each patient diagnosed with RLS/WED underwent a detailed neurological examination (performed by a neurologist) and an EMG examination to rule out polyneuropathy.

Results

Out of 76 COPD cases included in our study, 26.3 % (n?=?20) were diagnosed with RLS/WED (mean age 60.4?±?7.5 years, 20 males). The cases with RLS/WED had significantly lower body mass index (BMI) than cases without RLS/WED (p?=?0.009). There were no significant differences between cases with and without RLS/WED with respect to PFT, dyspnea scales, and arterial blood gas values. However, ESS was significantly different (p?=?0.016). There were no significant differences in RLS/WED scores and mean hs-CRP levels between COPD stages (p?=?0.424; p?=?0.518, respectively), while ESS was significantly different (p?=?0.016). ESS was significantly higher in stage B COPD than in stages A and D (p?=?0.005, p?=?0.008, respectively). Based on our model, we found that exacerbations and iron binding capacity (UIBC) were predictive factors for RLS/WED (p?<?0.100)

Conclusion

RLS/WED is a common disease in cases with stable COPD. Despite our hypothesis suggesting that the prevalence of RLS/WED in COPD is related with systemic inflammation, we did not find a significant association between hs-CRP and COPD cases with RLS/WED. However, we did find that UIBC is a predictive factor for the development of RLS/WED. Nonetheless, further studies are needed to understand the relationships between UIBC, low BMI, and the development of RLS/WED in COPD.
  相似文献   
93.
Objective: To assess postural balance in females with pregnancies complicated by hyperemesis gravidarum (HG).

Methods: In this observational study, postural balance during the first trimester was measured using the Biodex Balance System (BBS) in 41 pregnant females (20 females with pregnancies complicated by HG and 21 healthy controls). The overall stability index (OA), anterior-posterior stability index (APSI), medial-lateral stability index (MLSI) and fall risk test (FRT) scores were obtained from the mean scores of three trials on the BSS. The four measurements obtained from the BBS (OA, APSI, MLSI and FRT) were compared between healthy pregnant females and those with pregnancies complicated by HG (HG group).

Results: The mean OA and APSI scores were significantly higher in the HG group compared to healthy pregnant controls (p?p?>?0.05). The FRT scores of HG patients were higher than healthy pregnant females (p?=?0.001).

Conclusions: Pregnant females with HG have poor postural stability/balance and high fall risk test scores. HG causes decreased postural equilibrium in the first trimester of pregnancy.  相似文献   
94.
Among gastrointestinal stromal tumors (GISTs) of 10–15% are negative for KIT and PDGFRA, and most of these cases are SDH deficient. Recent studies have provided data on additional molecular alterations such as KRAS in KIT mutant GISTs. We aimed to assess the frequency and spectrum of somatic mutations in common oncogenes as well as copy number variations in GISTs negative for KIT and PDGFRA mutations. GISTs with wild type KIT/PDGFRA were tested via next generation sequencing for somatic mutations in 341 genes. SDHB immunohistochemistry to evaluate for SDH deficiency was also performed. Of 267 GISTs tested for KIT and PDGFRA mutations, 15 were wild type, of which eight cases had material available for further testing. All eight cases had loss of SDHB expression and had various molecular alterations involving ARID1A, TP53, and other genes. One case had a KRAS G12V (c.35G>T) mutation in both the primary gastric tumor and a post‐imatinib recurrence. This tumor had anaplastic features and was resistant to multiple tyrosine kinase inhibitors, ultimately resulting in cancer‐related mortality within 2 years of diagnosis. In conclusion, KRAS mutations occur in rare GISTs with wild type KIT and PDGFRA. These tumors may display immunohistochemical positivity for KIT and primary resistance to tyrosine kinase inhibitors. © 2014 Wiley Periodicals, Inc.  相似文献   
95.
Melanotic Schwannomas (MS) are rare tumors that share histological features with melanocytic tumors and schwannomas. However, their genetics are poorly understood. To elucidate the genetic characteristics of MS, we performed genome‐wide studies in a series of cases. Twelve MS cases were available for the study. Genomic DNAs extracted from formalin‐fixed paraffin embedded tumor tissues were subjected to copy number (CN) and allelic imbalance (AI) analysis by Single Nucleotide Polymorphism (SNP)‐array and screened for mutations in coding exons of 341 key cancer‐associated genes using a hybrid capture‐based next‐generation sequencing (NGS) assay. Sanger sequencing was used to further verify recurrent mutations detected by NGS study. SNP‐array analysis revealed remarkably stereotypic chromosomal abnormalities in MS. Hypodiploidy was common, typically involving monosomies of chromosomes 1, 2, and 17. All 12 samples showed mutations in PRKAR1A gene, including 2 cases with 2 mutations each. The 14 mutations were scattered across PRKAR1A, and most were inactivating mutations. AI on 17q, presenting as loss of heterozygosity with or without CN losses, combined with a PRKAR1A mutation was observed in 9/12 MS cases. The remaining 3 cases included the two samples harboring two mutations in PRKAR1A. MS exhibits a stereotypic pattern of chromosomal losses. In contrast, melanomas are typically characterized by the presence of multiple CN aberrations, without demonstrable differences in the frequency of losses and gains. Inactivation of both alleles of PRKAR1A by “two hits” observed in almost all cases underscores the central role of PRKAR1A in the pathogenesis of this neoplasm. © 2015 Wiley Periodicals, Inc.  相似文献   
96.
SYNTAX Score II (SSII) connects clinical variables with coronary anatomy. We investigated the prognostic value of SSII in patients with ST segment elevated myocardial infarction (STEMI) complicated with cardiogenic shock treated with primary percutaneous coronary intervention (PPCI). In this retrospective analysis, we evaluated the in-hospital prognostic impact of SSII on 492 patients with STEMI complicated with cardiogenic shock treated with PPCI. Patients were stratified by tertiles of SSII, in-hospital clinical outcomes were compared between those groups. In-hospital univariate analysis revealed higher rates of in-hospital death for patients with SSII in tertile 3, as compared to patients with SSII in tertile 1 (OR 17.4, 95% CI 10.0–30.2, p?<?0.001). After adjustment for confounding baseline variables, SSII in tertile 3 was associated with 6.2-fold hazard of in-hospital death (OR 6.2, 95% CI 2.6–14.1, p?<?0.001). SSII in patients with STEMI complicated with cardiogenic shock treated with PPCI provide an independent prognostic marker of in-hospital outcomes. Our data suggests SSII to be a simple, feasible and clinically applicable tool for rapid risk stratification in patients with STEMI complicated with cardiogenic shock treated with PPCI.  相似文献   
97.
98.
99.
100.

Background:

As a zoonotic pathogen, Encephalitozoon cuniculi is a cause of serious disease in animals and people. The present study was to evaluate the health status examination of this seropositive animal care worker in our previous study.

Methods:

Blood samples were taken from five workers. CIA test was applied to detect antibodies against E. cuniculi in blood serum. The indirect immunofluorescence antibody test was used as confirmation test. Seropositive worker had a complete medical examination.

Results:

Only one worker was found to be seropositive according to the results of the serological test. Sera positive to E. cuniculi was confirmed with IFAT and spores were detected in the urine sample of the worker. The worker was treated with albendazole.

Conclusion:

Rabbits should be examined routinely for the presence of anti-E. cuniculi antibody. People working with laboratory animal should avoid contact with urine and faeces of infected or pay attention to personal hygiene.  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