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   3239篇
  免费   202篇
  国内免费   40篇
耳鼻咽喉   11篇
儿科学   98篇
妇产科学   70篇
基础医学   454篇
口腔科学   33篇
临床医学   288篇
内科学   944篇
皮肤病学   63篇
神经病学   420篇
特种医学   64篇
外科学   255篇
综合类   6篇
预防医学   150篇
眼科学   60篇
药学   220篇
中国医学   4篇
肿瘤学   341篇
  2024年   10篇
  2023年   55篇
  2022年   121篇
  2021年   185篇
  2020年   119篇
  2019年   134篇
  2018年   141篇
  2017年   85篇
  2016年   115篇
  2015年   150篇
  2014年   153篇
  2013年   182篇
  2012年   298篇
  2011年   312篇
  2010年   168篇
  2009年   154篇
  2008年   217篇
  2007年   169篇
  2006年   171篇
  2005年   128篇
  2004年   120篇
  2003年   116篇
  2002年   92篇
  2001年   21篇
  2000年   8篇
  1999年   9篇
  1998年   14篇
  1997年   4篇
  1996年   6篇
  1995年   5篇
  1994年   2篇
  1993年   6篇
  1992年   3篇
  1991年   1篇
  1989年   2篇
  1985年   1篇
  1984年   2篇
  1978年   2篇
排序方式: 共有3481条查询结果,搜索用时 15 毫秒
21.
In β-thalassemia, the mechanism driving ineffective erythropoiesis (IE) is insufficiently understood. We analyzed mice affected by β-thalassemia and observed, unexpectedly, a relatively small increase in apoptosis of their erythroid cells compared with healthy mice. Therefore, we sought to determine whether IE could also be characterized by limited erythroid cell differentiation. In thalassemic mice, we observed that a greater than normal percentage of erythroid cells was in S-phase, exhibiting an erythroblast-like morphology. Thalassemic cells were associated with expression of cell cycle–promoting genes such as EpoR, Jak2, Cyclin-A, Cdk2, and Ki-67 and the antiapoptotic protein Bcl-XL. The cells also differentiated less than normal erythroid ones in vitro. To investigate whether Jak2 could be responsible for the limited cell differentiation, we administered a Jak2 inhibitor, TG101209, to healthy and thalassemic mice. Exposure to TG101209 dramatically decreased the spleen size but also affected anemia. Although our data do not exclude a role for apoptosis in IE, we propose that expansion of the erythroid pool followed by limited cell differentiation exacerbates IE in thalassemia. In addition, these results suggest that use of Jak2 inhibitors has the potential to profoundly change the management of this disorder.  相似文献   
22.

The liver contribution to the biological network underlying physical frailty in aging is underestimated. How best to measure this contribution magnitude and impact on health risk trajectories in frail individuals is not yet entirely clear. We analyzed the association of a novel liver frailty phenotype with the risk of death in older participants of the Salus in Apulia Study cohort. Clinical and physical examination, routine biomarkers, medical history, and anthropometry were analyzed in 1929 older adults (65?+). Physical frailty was classified by Cardiovascular Health Study criteria, and liver fibrosis risk by fibrosis-4 (FIB-4). The liver frailty phenotype was defined as physical frailty plus high-risk liver fibrosis (score?>?2.67). Physical frailty, high-risk liver fibrosis, and liver frailty subjects were compared to subjects without these conditions (non-frail). Proportional Cox regression tested the adjusted association between liver frailty and all-cause mortality for each category. The liver frailty prevalence was relatively low (3.8%), but higher in men (58.1%). Compared to non-frail older subjects, liver frailty subjects were significantly older (effect size (ES)???1.11, 95% confidence interval (CI)???1.35 to???0.87), with a lower education (ES 0.48, 95%CI 0.24 to 0.71) and higher multimorbidity (ES 15.81, 95%CI 4.20 to 27.41). Cox multivariate analyses showed a two-fold increased risk of overall mortality (hazard ratio 2.09, 95%CI 1.16–3.74) even after the adjustment for age, sex, education, and alcohol consumption. The liver frailty phenotype runs twice the risk of overall mortality compared with the non-frail population. This clinical tool, validated in a Southern Italian population, is based on simple sets of measures that can conveniently be assessed also in the primary care setting.

  相似文献   
23.
MED13L haploinsufficiency has recently been described as responsible for syndromic intellectual disability. We planned a search for causative gene variants in seven subjects with intellectual disability and overlapping dysmorphic facial features such as bulbous nasal tip, short mouth and straight eyebrows. We found two de novo frameshift variants in MED13L, consisting in single-nucleotide deletion (c.3765delC) and duplication (c.607dupT). A de novo nonsense variant (c.4420A>T) in MED13L was detected in a further subject in the course of routine whole-exome sequencing. By analyzing the clinical data of our patients along with those recently described in the literature, we confirm that there is a common, recognizable phenotype associated with MED13L haploinsufficiency, which includes intellectual disability and a distinctive facial appearance. Congenital heart diseases are found in some subjects with various degree of severity. Our observation of cleft palate, ataxia, epilepsy and childhood leukemia observed in single cases broadens the known clinical spectrum. Haploinsufficiency for MED13L should be considered in the differential diagnosis of the 1p36 microdeletion syndrome, due to overlapping dysmorphic facial features in some patients. The introduction of massive parallel-sequencing techniques into clinical practice is expected to allow for detection of other causative point variants in MED13L. Analysis of genomic data in connection with deep clinical evaluation of patients could elucidate genetic heterogeneity of the MED13L haploinsufficiency phenotype.  相似文献   
24.
Introduction: Since 2006, biosimilars have been available in several countries worldwide, thus allowing for potential savings in pharmaceutical expenditure. However, there have been numerous debates about the interchangeability of biosimilars and reference products based on concerns of immunogenicity by switching between biological products, which may cause lack of effect and toxicity.

Areas covered: The authors provide the reader with an overview of the different positions of regulatory authorities on the interchangeability and automatic substitution of biosimilars and reference products. Presently, the FDA allows automatic substitution without prescriber intervention if the biosimilar is interchangeable with reference products, while the European Medicines Agency delegate to each single EU member state.

Expert opinion: Different approaches in defining interchangeability and automatic substitution call for harmonization to increase confidence of healthcare professionals and patients about the clinical impact of switching. Networks of electronic healthcare records and administrative databases, potentially linkable to clinical charts and registries may rapidly assess frequency and benefit-risk profile of different switching patterns in routine care at different levels, thus integrating and strengthening pre-marketing evidence.  相似文献   

25.
26.
27.
Clinical Rheumatology - Kawasaki disease (KD) is the most frequent cause of acquired heart disease in children in high-income countries because of coronary artery involvement. Risk factors for...  相似文献   
28.
Chronic rejection (CR) of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation. Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy, CR still represents an important cause of graft injury, which might be irreversible, leading to graft loss requiring re-transplantation. To date, we still do not fully appreciate the mechanisms underlying this process. In addition to T cell-mediated CR, which was initially the only recognized type of CR, recently a new form of liver allograft CR, antibody-mediated CR, has been identified. This has indeed opened an era of thriving research and renewed interest in the field. Liver biopsy is needed for a definitive diagnosis of CR, but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation. Moreover, the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury, which should not be disregarded. Therapies for CR may only be effective in the “early” phases, and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage. Herein, we provide an overview of the current knowledge and research on CR, focusing on early detection, identification of non-invasive biomarkers, immunosuppressive management, re-transplantation and future perspectives of CR.  相似文献   
29.
Neurological Sciences - Monoclonal antibodies targeting the calcitonin gene-related peptide, including erenumab, are migraine-specific preventive treatments, whose long-term effectiveness has still...  相似文献   
30.
The family climate has notable impact on cognitive, emotional, behavioural, social and physical development of children and adolescents and can be influenced by parents' health status. The present study aimed at evaluating whether living with a parent with alcohol use disorder negatively influences the perceived emotional family climate, parental attitudes and internal representations of family relationships. Forty-five children living with a parent with alcohol use disorder and 45 controls, matched for sex and age, completed the Level of Expressed Emotion Scale and the Family Attitudes Questionnaire. Their significant parent completed the Parental Attitudes Scale. The results suggested that living with a parent with an alcohol use disorder increased the risk of having perceived higher levels of emotional response, attitude towards illness and expectations from their parents; it also increased the probability of being exposed to lower parental pleasure and of having represented worse family relationships. Emotion regulation interventions might be useful to protect children living with a parent with alcohol use disorder from a potential chaotic and unpredictable family environment.  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