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   3256篇
  免费   120篇
  国内免费   79篇
耳鼻咽喉   5篇
儿科学   76篇
妇产科学   47篇
基础医学   390篇
口腔科学   15篇
临床医学   171篇
内科学   747篇
皮肤病学   13篇
神经病学   183篇
特种医学   92篇
外科学   262篇
综合类   241篇
预防医学   248篇
眼科学   6篇
药学   760篇
中国医学   85篇
肿瘤学   114篇
  2023年   44篇
  2022年   57篇
  2021年   134篇
  2020年   80篇
  2019年   99篇
  2018年   73篇
  2017年   66篇
  2016年   68篇
  2015年   78篇
  2014年   130篇
  2013年   173篇
  2012年   103篇
  2011年   130篇
  2010年   123篇
  2009年   121篇
  2008年   159篇
  2007年   124篇
  2006年   118篇
  2005年   120篇
  2004年   98篇
  2003年   75篇
  2002年   66篇
  2001年   56篇
  2000年   59篇
  1999年   38篇
  1998年   54篇
  1997年   44篇
  1996年   52篇
  1995年   51篇
  1994年   39篇
  1993年   39篇
  1992年   46篇
  1991年   38篇
  1990年   26篇
  1988年   27篇
  1987年   30篇
  1986年   26篇
  1985年   32篇
  1984年   62篇
  1983年   29篇
  1982年   45篇
  1981年   51篇
  1980年   44篇
  1979年   36篇
  1978年   44篇
  1976年   32篇
  1975年   29篇
  1974年   31篇
  1973年   28篇
  1972年   32篇
排序方式: 共有3455条查询结果,搜索用时 15 毫秒
1.
The coronavirus disease 2019 (COVID-19) pandemic continues to be a global problem with over 438 million cases reported so far. Although it mostly affects the respiratory system, the involvement of extrapulmonary organs, including the liver, is not uncommon. Since the beginning of the pandemic, metabolic com-orbidities, such as obesity, diabetes, hypertension, and dyslipidemia, have been identified as poor prognostic indicators. Subsequent metabolic and lipidomic studies have identified several metabolic dysfunctions in patients with COVID-19. The metabolic alterations appear to be linked to the course of the disease and inflammatory reaction in the body. The liver is an important organ with high metabolic activity, and a significant proportion of COVID-19 patients have metabolic comorbidities; thus, this factor could play a key role in orchestrating systemic metabolic changes during infection. Evidence suggests that metabolic dysregulation in COVID-19 has both short- and long-term metabolic implications. Furthermore, COVID-19 has adverse associations with metabolic-associated fatty liver disease. Due to the ensuing effects on the renin-angiotensin-aldosterone system and ammonia metabolism, COVID-19 can have significant implications in patients with advanced chronic liver disease. A thorough understanding of COVID-19-associated metabolic dysfunction could lead to the identification of important plasma biomarkers and novel treatment targets. In this review, we discuss the current understanding of metabolic dysfunction in COVID-19, focusing on the liver and exploring the underlying mechanistic pathogenesis and clinical implications.  相似文献   
2.
间歇性禁食是一种新的饮食干预策略,其可能改善恶性肿瘤治疗的疗效并减少并发症。 限时进食是间歇性禁食的 一种特殊形式,通常仅限制每天的进食时间窗而不限制热量,除了和其他间歇性禁食手段一样能够控制体重并改善代谢紊乱 以外,限时进食还能调节昼夜节律并影响自噬水平,具有潜在的抗衰作用,相关研究已经表明了它预防肿瘤发生以及减缓肿 瘤发展的潜力。 同时,由于实施方案便利、不良反应轻微,限时进食有着不错的依从性及安全性,有可能成为一种适合肿瘤患 者长期实施的辅助治疗方案乃至健康生活方式。 本文从改善肥胖和代谢紊乱、调节昼夜节律和自噬水平以及目前与肿瘤相 关的研究进展这三个方面阐述了限时进食对恶性肿瘤的潜在作用,旨在为将来的相关研究提供理论依据和探索方向,探讨限 时进食作为一种营养干预手段对恶性肿瘤发生的潜在预防作用以及对恶性肿瘤的治疗或辅助治疗作用,以期可以完善对肿 瘤患者的营养干预策略,改善患者的生活质量及预后。  相似文献   
3.
4.
《Jornal de pediatria》2021,97(6):595-602
ObjectiveTo discuss the approach to patients diagnosed with growth hormone deficiency (GHD) in childhood during the transition period from puberty to adulthood, focusing on the following: (1) physiology; (2) effects of recombinant human GH (rhGH) interruption/reinstitution after adult height achievement; (3) re-evaluation of somatrotropic axis; (4) management of rhGH reinstitution, when necessary.Source of dataNarrative review of the literature published at PubMed/MEDLINE until September 2020 including original and review articles, systematic reviews and meta-analyses.Synthesis of dataGrowth hormone is crucial for the attainment of normal growth and for adequate somatic development, which does not end concomitantly with linear growth. Retesting adolescents who already meet the criteria that predict adult GHD with high specificity is not necessary. Patients with isolated GHD have a high likelihood of normal response to GH testing after puberty. Adolescents with confirmed GHD upon retesting should restart rhGH replacement and be monitored according to IGF-I levels, clinical parameters, and complementary exams.ConclusionPatients with isolated idiopathic GHD in childhood are a special group who must be reevaluated for GHD as many of them have normal GH provocative tests upon retesting after puberty. Patients who confirm the persistence of GHD in the transition period should maintain rhGH replacement in order to reach an ideal peak bone mass, satisfactory body composition, lipid and glucose profiles, and quality of life.  相似文献   
5.
Neurological aging is frequently viewed as a linear process of decline, whereas in reality, it is a dynamic non-linear process. The dynamic nature of neurological aging is exemplified during midlife in the female brain. To investigate fundamental mechanisms of midlife aging that underlie risk for development of Alzheimer’s disease (AD) in late life, we investigated the brain at greatest risk for the disease, the aging female brain. Outcomes of our research indicate that mid-life aging in the female is characterized by the emergence of three phases: early chronological (pre-menopause), endocrinological (peri-menopause) and late chronological (post-menopause) aging. The endocrinological aging program is sandwiched between early and late chronological aging. Throughout the three stages of midlife aging, two systems of biology, metabolic and immune, are tightly integrated through a network of signaling cascades. The network of signaling between these two systems of biology underlie an orchestrated sequence of adaptative starvation responses that shift the brain from near exclusive dependence on a single fuel, glucose, to utilization of an auxiliary fuel derived from lipids, ketone bodies. The dismantling of the estrogen control of glucose metabolism during mid-life aging is a critical contributor to the shift in fuel systems and emergence of dynamic neuroimmune phenotype. The shift in fuel reliance, puts the largest reservoir of local fatty acids, white matter, at risk for catabolism as a source of lipids to generate ketone bodies through astrocytic beta oxidation. APOE4 genotype accelerates the tipping point for emergence of the bioenergetic crisis. While outcomes derived from research conducted in the female brain are not directly translatable to the male brain, the questions addressed in a female centric program of research are directly applicable to investigation of the male brain. Like females, males with AD exhibit deficits in the bioenergetic system of the brain, activation of the immune system and hallmark Alzheimer’s pathologies. The drivers and trajectory of mechanisms underlying neurodegeneration in the male brain will undoubtedly share common aspects with the female in addition to factors unique to the male. Preclinical and clinical evidence indicate that midlife endocrine aging can also be a transitional bridge to autoimmune disorders. Collectively, the data indicate that endocrinological aging is a critical period “tipping point” in midlife which can initiate emergence of the prodromal stage of late-onset-Alzheimer’s disease. Interventions that target both immune and metabolic shifts that occur during midlife aging have the potential to alter the trajectory of Alzheimer’s risk in late life. Further, to achieve precision medicine for AD, chromosomal sex is a critical variable to consider along with APOE genotype, other genetic risk factors and stage of disease.  相似文献   
6.
目的探究叶酸代谢基因多态性及同型半胱氨酸(Hcy)水平与新生儿早产、出生体重的关系。方法选取我院2018年11月~2019年3月收治的80例孕妇进行研究,于孕早期采集口腔黏膜标本予以检测,以检测结果为标准,将叶酸代谢障碍遗传风险分为无/低风险(39例)和中/高风险(41例);同时检测孕妇的Hcy水平,并详细记录。分析不同基因型及Hcy水平与新生儿早产、出生体重的相关性。结果Hcy水平与新生儿出生体重呈正相关(r=0.168,P=0.002),MTRR A66G基因型与新生儿早产呈正相关(r=0.174,P=0.001),基因型总风险与新生儿早产呈正相关(r=0.159,P=0.004)。中/高风险孕妇早产率为20.51%(8/39),无/低风险孕妇早产率为4.88%(2/41),中/高风险孕妇早产率高于无/低风险组,差异有统计学意义(P<0.05)。分娩巨大儿孕妇Hcy水平为(5.76±0.73)μmol/L,分娩正常体重儿孕妇Hcy水平为(4.23±0.59)μmol/L,分娩极低体重儿孕妇Hcy水平为(4.01±0.56)μmol/L,分娩巨大儿孕妇Hcy水平高于分娩正常体重儿孕妇和分娩极低体重儿孕妇HCY水平,差异有统计学意义(P<0.05)。叶酸代谢障碍不同风险程度出生体重分布相比,差异无统计学意义(P>0.05)。结论叶酸代谢能力与早产具有相关性,叶酸代谢障碍越严重,早产儿的发生率越高;孕妇Hcy水平与新出生儿体重具有相关性,孕妇Hcy水平越高,新生儿出生体重越重。  相似文献   
7.
ObjectiveHyperglycemia leads to increase advanced glycation end products (AGEs) in patients with type 1 and type 2 diabetes. Subsequently, formation of AGEs can cause increased plantar fascial thickness (PFT), an imaging feature of plantar fasciitis (PF). This study evaluates the prevalence of PF in a contemporary cohort of type 1 diabetes and type 2 diabetes patients managed according to current standards, compared to patients without diabetes.Research design and methodsThis is a five-year prevalence study in a large tertiary health system (approximately 535,000 patients/visits/year) with a single electronic medical record (EMR), applying a cohort discovery tool and database screen (Data Direct) with use of ICD-9 and ICD-10 codes. All patients with a PF diagnosis between 01/01/2011 and 01/01/2016 were included and divided into 3 groups: type 1 diabetes (7148 patients), type 2 diabetes (61,632 patients), and no diabetes (653,659 patients). Prevalence rates were calculated, accounting for other risk factors including BMI and gender using Fisher's exact test.ResultsThe overall prevalence of PF in the entire study population was 0.85%. Prevalence rates were higher in patients with diabetes, particularly with type 2 diabetes (42% and 64% higher compared with patients with type 1 diabetes and no diabetes respectively). Individually, PF rates were 0.92% in type 1 diabetes and 1.31% in type 2 diabetes compared with 0.80% in patients with no diabetes (Type 1 vs. no diabetes p = 0.26; Type 2 vs. no diabetes p ? 0.0001; Type 1 vs. Type 2 diabetes p = 0.0054). Females in all groups had higher prevalence of PF than males (p ? 0.0001 for all), with those patients with diabetes having higher prevalence rates than those without diabetes. Patients with higher BMI levels (BMI ≥ 30 kg/m2) were also more likely to have PF in all categories except males with type 1 diabetes (p = 0.40).ConclusionsIn this large contemporary population managed in a tertiary health system, prevalence rates of PF were substantially higher in patients with diabetes compared with no diabetes, particularly in type 2 diabetes. Female gender and higher BMI were also associated with higher prevalence of PF in this cohort.  相似文献   
8.
The discovery of clear molecular mechanisms of early cardiac and vascular complications in patients with prediabetes and known diabetes mellitus are core element of stratification at risk with predictive model creation further. Previous clinical studies have shown a pivotal role of impaired signaling axis of fibroblast growth factor 23 (FGF23), FGF23 receptor isoforms and its co-factor Klotho protein in cardiovascular (CV) complications in prediabetes and diabetes. Although there were data received in clinical studies, which confirmed a causative role of altered function of FGF-23/Klotho protein axis in manifestation of CV disease in prediabetes and type 2 diabetes mellitus (T2DM), the target therapy of these diseases directing on improvement of metabolic profiles, systemic and adipokine-relating inflammation by beneficial restoring of dysregulation in FGF-23/Klotho protein axis remain to be not fully clear. The aim of the review was to summarize findings regarding the role of impaired FGF-23/Klotho protein axis in developing CV complications in patients with prediabetes and type 2 diabetes mellitus. It has been elucidated that elevated levels of FGF-23 and deficiency of Klotho protein in peripheral blood are predictors of CV disease and CV outcomes in patients with (pre) diabetes, while predictive values of dynamic changes of the concentrations of these biomarkers require to be elucidated in detail in the future.  相似文献   
9.
AimsThe aim of this study is to investigate the effects of a low-carbohydrate staple food (i.e., low-carbohydrate bread) on glucose and lipid metabolism and pancreatic and enteroendocrine hormone secretion in comparison with meals containing normal-carbohydrate bread, without consideration of the carbohydrate content of the side dishes.MethodsT2DM patients (n = 41) were provided meals containing low-carbohydrate bread (LB) together with side dishes or normal-carbohydrate bread (NB) together with side dishes every other day as a breakfast. Blood glucose levels were evaluated by using a continuous glucose monitoring system; blood samples were collected before and 1 and 2 h after the breakfast.ResultsPostprandial blood glucose levels, plasma insulin, plasma glucose-dependent insulinotropic polypeptide (GIP) and plasma triglyceride were significantly lower and plasma glucagon levels were significantly higher in LB compared with those in NB. Plasma glucagon-like peptide-1 (GLP-1) levels did not differ in the LB and NB groups.ConclusionsThese results indicate that changing only the carbohydrate content of the staple food has benefits on glucose and lipid metabolism in T2DM patients concomitant with the decrease of insulin and GIP secretion, which ameliorate body weight gain and insulin resistance.  相似文献   
10.
Platelets and Toll-like receptor (TLR) signalling play a role in the immune response during sepsis. Although preclinical knowledge about the role of platelet TLR signalling is increasing, data during human sepsis are less abundant. Moreover, controversy remains about the effect of the TLR4 agonist lipopolysaccharide (LPS) on platelet activation. We therefore assessed platelet TLR expression during human and murine sepsis. Moreover, we investigated the effect of TLR4 signalling on platelet activation and TLR expression. Platelets from healthy controls stimulated with LPS did not show classical platelet activation (P-selectin, CD63 and phosphatidylserine expression), potentiation of subthreshold agonist stimulation nor platelet-leukocyte complex formation. LPS stimulation however did increase maximal mitochondrial respiration in a TLR4-dependent manner. Platelet stimulation with LPS did not alter TLR expression. Platelet stimulation with thrombin receptor activating peptide increased TLR5 and TLR9, but not TLR2 or TLR4 expression. Platelets from patients with sepsis and mice with experimental sepsis showed platelet activation, but unaltered TLR expression. These results indicate that sepsis-induced platelet activation is not associated with altered platelet TLR expression and, although platelets are responsive to LPS, stimulation of platelet TLR4 does not result in classical platelet activation.  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