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   730篇
  免费   61篇
  国内免费   2篇
耳鼻咽喉   15篇
儿科学   23篇
妇产科学   30篇
基础医学   57篇
口腔科学   93篇
临床医学   59篇
内科学   190篇
皮肤病学   14篇
神经病学   21篇
特种医学   14篇
外科学   120篇
综合类   5篇
预防医学   56篇
眼科学   22篇
药学   28篇
中国医学   2篇
肿瘤学   44篇
  2024年   2篇
  2023年   6篇
  2022年   23篇
  2021年   28篇
  2020年   26篇
  2019年   34篇
  2018年   56篇
  2017年   14篇
  2016年   20篇
  2015年   38篇
  2014年   48篇
  2013年   39篇
  2012年   69篇
  2011年   73篇
  2010年   52篇
  2009年   40篇
  2008年   38篇
  2007年   40篇
  2006年   27篇
  2005年   32篇
  2004年   15篇
  2003年   15篇
  2002年   14篇
  2001年   1篇
  2000年   6篇
  1999年   6篇
  1998年   4篇
  1997年   3篇
  1996年   3篇
  1995年   4篇
  1994年   1篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1979年   1篇
  1971年   1篇
  1968年   1篇
  1967年   1篇
  1966年   2篇
排序方式: 共有793条查询结果,搜索用时 15 毫秒
781.
Objectives. We investigated the population burden of betel quid abuse and its related impact on oral premalignant disorders (OPDs) in South, Southeast, and East Asia.Methods. The Asian Betel-Quid Consortium conducted a multistage sampling of 8922 representative participants from Taiwan, Mainland China, Malaysia, Indonesia, Nepal, and Sri Lanka. Participants received an interviewer-administered survey and were examined for oral mucosal disorders.Results. The prevalence of betel quid abuse was 0.8% to 46.3% across 6 Asian populations. The abuse frequency was over 40.5% for current chewers, with the highest proportion in Nepalese and Southeast Asian chewers (76.9%−99.6%). Tobacco-added betel quid conferred higher abuse rates (74.4%−99.6%) among Malaysian, Indonesian, and Sri Lankan men than did tobacco-free betel quid (21.8%−89.1%). Gender, lower education level, younger age at chewing initiation, and clustering of familial betel quid use significantly contributed to higher abuse rates. Indonesian betel quid abusers showed the highest prevalence of OPDs and had a greater risk of OPDs than did nonabusers.Conclusions. Betel quid abuse is high in regions of Asia where it is customarily practiced, and such abuse correlates highly with OPDs. By recognizing abuse-associated factors, health policies and preventive frameworks can be effectively constructed to combat these oral preneoplasms.The chewing of betel quid, a combination of areca nut, betel leaf, slaked lime, and region-dependent flavoring ingredients, is a uniquely Asian, culturally derived lifestyle habit. Bred from ancient tradition, its use is socially accepted in all groups, including women and young children, although other substance use such as tobacco smoking is deemed objectionable.1,2 Chemical composition studies have showed that areca nut includes psychoactive alkaloids, of which arecoline contributes the most quantity.3 By raising epinephrine and norepinephrine plus modulation of cholinergic and monoamine transmission, areca nut exerts neurobiological effects on the sympathetic and parasympathetic nervous systems.3–5 In human studies, tolerance and withdrawal symptoms have been clearly detected in regular betel quid chewers.6–8 Such a pharmacological profile is comparable with nicotine, a well-known substance that leads to abuse and dependence. In recent decades, successful marketing of commercially manufactured betel quid has dramatically increased its accessibility and widespread use throughout Asia.9 An increased availability indicates that betel quid may be abused throughout different cultures, but the extent is unknown.Studies on the natural history of oral cancer suggest that several oral premalignant disorders (OPDs), including oral lichen planus (OLP), oral submucous fibrosis (OSF), oral leukoplakia (OL) and oral erythroplasia, precede the development of this neoplasm.10 In Asia, the prevalence of oral precancerous conditions and lesions was estimated to be 1.7% to 11.7% in western India,11 4.4% to 12.7% in southern Taiwan,12,13 0.1% to 4.7% in the Hunan province of Mainland China,14 1.4% in Malaysia,15 and 6.7% in the central Sri Lanka.16 Although there is evidence to support that chronic consumption of betel quid products, with or without added tobacco, is a central etiological agent for OPD and neoplasms of the oral cavity, pharynx, esophagus and larynx,10,17–23 no data are available concerning the oral precancerous consequences among betel quid abusers.To study the health effects of betel quid consumption in Asian populations and mobilize outreach activities in disease prevention, in 2008, the Center of Excellence for Environmental Medicine at Kaohsiung Medical University in Kaohsiung, Taiwan, in consultation with the World Health Organization (WHO) Collaborating Centre for Oral Cancer in the United Kingdom, launched an international collaborative project that constitutes the Asian Betel-quid Consortium (ABC) study. Six large research centers from East Asia (Kaohsiung Medical University, Taiwan, and Central South University, Changsha, Mainland China), Southeast Asia (Airlangga University, Surabaya, Indonesia and University of Malaya, Kuala Lumpur, Malaysia), and South Asia (University of Peradeniya, Peradeniya, Sri Lanka and Kathmandu University, Kavrepalanchwok, Nepal) participated in this investigation. Because of varying practices and particular marketing of betel quid products in those countries (detailed explanations shown in Table A, available as a supplement to the online version of this article at http://www/ajph.org), present study actions are promisingly warranted. The purposes of this report are twofold: (1) to present the current population burden of betel quid abuse and the factors associated with this behavior in the investigated Asian communities, and (2) to evaluate the impact of betel quid abuse on oral premalignant disorders.  相似文献   
782.
ObjectiveThe objective of this study was to assess the efficacy of a tobacco cessation intervention conducted by different dental specialists directed at a group of patients with tobacco-related oral diseases or undergoing implant treatment.MethodsThe study design was a multicentre, nonrandomized prospective cohort study to examine the effects of smoking cessation. The target patients were current smokers (aged ≥20 years) with an oral potentially malignant disorder or periodontitis and those seeking dental implants. A total of 74 patients were enrolled in the study. All dental specialists who participated in the trial completed an e-learning Japan Smoking Cessation Training Outreach Project (J-STOP) tobacco cessation education programme. Nicotine dependence was evaluated by the Fagerstrom Test for Nicotine Dependence. Cessation status was verified biochemically by measurement of salivary cotinine or exhaled carbon monoxide. Tobacco cessation intervention was implemented for 8 weeks with or without nicotine replacement therapy with follow-up for 12 months.ResultsA total of 61 patients agreed to the tobacco cessation intervention. The mean biochemically confirmed tobacco abstinence rate was 37.7% at month 3, 34.4% at month 6, and 32.8% at month 12. The highest rate of biochemically confirmed tobacco abstinence at month 12 was among patients receiving implant treatment (42.9%) followed by patients with oral potentially malignant disorder (37.1%), and those with periodontitis (21.1%).ConclusionThis interventional study demonstrates the challenges encountered and the feasibility of tobacco cessation intervention among Japanese patients attending dental specialists who had completed an e-learning course on smoking cessation. Making tobacco cessation an integral part of patient management by dental specialists requires further evaluation.  相似文献   
783.

Background and objective

Infertility is a global public health issue and is a low control stressor often leading to increased level of anxiety and depression. The objective of this study was to determine the prevalence of anxiety and depression and their related factors among Iranian infertile patients.

Materials and methods

This cross-sectional study included 1128 infertile patients (479 men and 649 women) in a referral fertility center in Tehran, Iran from January 2014 to March 2015. The Hospital Anxiety and Depression Scale (HADS) were administrated to all participants.

Results

The prevalence rates of anxiety and depression were 49.6% and 33.0%, respectively. Based on adjusted analysis, females were 2.26 times more likely to have anxiety symptoms than males (OR = 2.26, 95% CI: 1.75–2.90), while depression rate was not related to sex (OR = 1.09, 95% CI: 0.84–1.42). Patients with  5 years infertility duration were 1.51-fold and 1.30-fold more likely than others to have anxiety and depressive symptoms, respectively.

Conclusion

We found that the anxiety and depression rates were very high among infertile patients. Thus, there may be a need for infertile patients to receive ongoing psychological interventions and support that matches their background during ART in order to reduce level of anxiety and depression.  相似文献   
784.
Journal of Neuro-Oncology - The impact of multiple primary tumors, in the setting of malignant glioma (MG), has not been heavily explored. We extracted demographics and clinical data from the...  相似文献   
785.
Memory for events from the distant past relies on multiple brain regions, but little is known about the underlying neural dynamics that give rise to such abilities. We recorded neural activity in the hippocampus and retrosplenial cortex of two female rhesus macaques as they visually selected targets in year-old and newly acquired object-scene associations. Whereas hippocampal activity was unchanging with memory age, the retrosplenial cortex responded with greater magnitude alpha oscillations (10–15 Hz) and greater phase locking to memory-guided eye movements during retrieval of old events. A similar old-memory enhancement was observed in the anterior cingulate cortex but in a beta2/gamma band (28–35 Hz). In contrast, remote retrieval was associated with decreased gamma-band synchrony between the hippocampus and each neocortical area. The increasing retrosplenial alpha oscillation and decreasing hippocampocortical synchrony with memory age may signify a shift in frank memory allocation or, alternatively, changes in selection among distributed memory representations in the primate brain.SIGNIFICANCE STATEMENT Memory depends on multiple brain regions, whose involvement is thought to change with time. Here, we recorded neuronal population activity from the hippocampus and retrosplenial cortex as nonhuman primates searched for objects embedded in scenes. These memoranda were either newly presented or a year old. Remembering old material drove stronger oscillations in the retrosplenial cortex and led to a greater locking of neural activity to search movements. Remembering new material revealed stronger oscillatory synchrony between the hippocampus and retrosplenial cortex. These results suggest that with age, memories may come to rely more exclusively on neocortical oscillations for retrieval and search guidance and less on long-range coupling with the hippocampus.  相似文献   
786.
BackgroundBladder cancer poses a great burden on society and its high rate of recurrence and treatment failure necessitates use of appropriate animal models to study its pathogenesis and test novel treatments. Orthotopic models are superior to other types since they provide a normal microenvironment. Four methods are described for developing bladder cancer models inside the animal''s bladder. Direct intramural injection is one of these methods and is widely used. However, its efficacy in model development has not yet been studied. We aimed to evaluate the efficacy and success rate of the direct intramural injection method of developing an orthotopic model for the study of bladder cancer.MethodTumor cell lines were prepared in four microtubes. Aliquots of 200 × 103 cells were injected through a 27 gauge needle into the ventral wall of the bladders of 4 male and 4 female BALB/c mice following a midline 1 cm laparotomy incision. In addition, 1 million cells from each microtube were injected into the flanks of control mice. To prevent infection and alleviate pain, 5 mg/kg enrofloxacin and 2.5 mg/kg flunixin meglumine, respectively, were injected subcutaneously.ResultsTumors formed in all mice, resulting in 100% take rate and zero post‐operation mortality. Surgery time was ≤15 min per mouse. In two mice, tumors were found in the peritoneal space as well.ConclusionDirect intramural injection is a rapid, reliable, and reproducible method for developing orthotopic models of bladder cancer. It can be done on both male and female mice and only requires readily available surgical tools. However, needle track can result in cell spillage and peritoneal tumors.  相似文献   
787.
788.
Herlyn-Werner-Wunderlich (HWW) syndrome is a rare congenital anomaly of female urogenital tract involving combined mullerian duct anomalies and mesonephric duct malformation characterized by uterus didelphys, obstructed hemi-vagina and ipsilateral renal agenesis which is also known as OHVIRA syndrome. It can be classified based on a completely or incompletely obstructed hemivagina. It presents soon after menarche or shows delayed presentation depending on the type. The most common presentation is lower abdominal pain, dysmenorrhea, and abdominal mass in the lower abdomen secondary to hematometra or hematocolpos. We present a 15-year-old unmarried patient with an unusual case of OHVIRA syndrome suffering from dysmenorrhea and painful mass in suprapubic region. We described the role of imaging modalities in diagnosis of the Herlyn-Werner Wunderlich syndrome with a review of literature. On USG and MRI, she had right renal agenesis with compensatory hypertrophy of the left kidney, didelphic uterus with an obstructed hemi-vagina on right side which led to marked distention of ipsilateral cervix and proximal vagina in the form of hematometrocolpos. OHVIRA syndrome can present early or late, depending on the type. In patients with uterine and vaginal abnormalities, a work-up for associated renal anomalies should be performed. The choice imaging modalities for the diagnosis of OHVIRA syndrome are ultrasound and MRI. Knowing the imaging findings of this rare condition is crucial for early diagnosis in order to prevent complications which may lead to endometriosis and infertility.  相似文献   
789.
790.

Objectives

The association of OLP with other autoimmune processes points to the possibility that OLP-affected patients are actually developing an autoimmune status that predisposes them to autoaggression against different targets. This systematic review and meta-analysis aim to evaluate the current evidence on the prevalence of autoimmune disorders in patients with OLP and their magnitude of association.

Methods

We searched PubMed, Embase, Web of Science, Scopus databases for the studies published before May 2021, with no limitation in regards to their publication date or language. We evaluated the quality of studies, carried out meta-analyses and performed heterogeneity, subgroups, meta-regression, and small-study effects analyses.

Results

Inclusion criteria were met by 153 studies (23,327 patients). Our results indicate the existence of high prevalence and a frequent association between OLP and some autoimmune disorders, especially in regards to thyroid disease (PP = 7.96%, 95% CI = 6.32–9.75; OR = 1.99, 95% CI = 1.60–2.49, < 0.001) and diabetes mellitus (PP = 9.41%,95% CI = 8.16–10.74; OR = 1.64, 95% CI = 1.34–2.00, < 0.001).

Conclusions

Our study demonstrates the existence of a comorbidity between autoimmune thyroid diseases as well as between diabetes mellitus and OLP respectively. Quality of evidence should be upgraded on other autoimmune diseases (fibromyalgia, gastrointestinal disorders, rheumatic diseases, Sjogren's syndrome, lupus erythematosus, and dermatological diseases) for which the current data do not allow us to know whether they are really associated with OLP.  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