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   289199篇
  免费   22834篇
  国内免费   8622篇
耳鼻咽喉   1585篇
儿科学   9568篇
妇产科学   2696篇
基础医学   27555篇
口腔科学   5084篇
临床医学   29443篇
内科学   65700篇
皮肤病学   4266篇
神经病学   30904篇
特种医学   7971篇
外国民族医学   7篇
外科学   21010篇
综合类   37920篇
现状与发展   34篇
一般理论   9篇
预防医学   25285篇
眼科学   2818篇
药学   27528篇
  223篇
中国医学   14745篇
肿瘤学   6304篇
  2024年   572篇
  2023年   5595篇
  2022年   7900篇
  2021年   14911篇
  2020年   13828篇
  2019年   11074篇
  2018年   10958篇
  2017年   10666篇
  2016年   10940篇
  2015年   10527篇
  2014年   19781篇
  2013年   22640篇
  2012年   16439篇
  2011年   18043篇
  2010年   14053篇
  2009年   13838篇
  2008年   13725篇
  2007年   13425篇
  2006年   11737篇
  2005年   9846篇
  2004年   8441篇
  2003年   7279篇
  2002年   6058篇
  2001年   5375篇
  2000年   4359篇
  1999年   3903篇
  1998年   3673篇
  1997年   3245篇
  1996年   2932篇
  1995年   2697篇
  1994年   2454篇
  1993年   2143篇
  1992年   2082篇
  1991年   1853篇
  1990年   1530篇
  1989年   1352篇
  1988年   1232篇
  1987年   1149篇
  1986年   1025篇
  1985年   1263篇
  1984年   1098篇
  1983年   711篇
  1982年   854篇
  1981年   690篇
  1980年   598篇
  1979年   473篇
  1978年   431篇
  1977年   340篇
  1976年   343篇
  1975年   135篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
《Saudi Pharmaceutical Journal》2022,30(11):1572-1588
Non-alcoholic fatty liver disease (NAFLD) is one of the most common complications of a metabolic syndrome caused by excessive accumulation of fat in the liver. Orthosiphon stamineus also known as Orthosiphon aristatus is a medicinal plant with possible potential beneficial effects on various metabolic disorders. This study aims to investigate the in vitro inhibitory effects of O. stamineus on hepatic fat accumulation and to further use the computational systems pharmacology approach to identify the pharmacokinetic properties of the bioactive compounds of O. stamineus and to predict their molecular mechanisms against NAFLD. Methods: The effects of an ethanolic extract of O. stamineus leaves on cytotoxicity, fat accumulation and antioxidant activity were assessed using HepG2 cells. The bioactive compounds of O. stamineus were identified using LC/MS and two bioinformatics databases, namely the Traditional Chinese Medicine Integrated Database (TCMID) and the Bioinformatics Analysis Tool for the Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM). Pathway enrichment analysis was performed on the predicted targets of the bioactive compounds to provide a systematic overview of the molecular mechanism of action, while molecular docking was used to validate the predicted targets. Results: A total of 27 bioactive compounds corresponding to 50 potential NAFLD-related targets were identified. O. stamineus exerts its anti-NAFLD effects by modulating a variety of cellular processes, including oxidative stress, mitochondrial β-oxidation, inflammatory signalling pathways, insulin signalling, and fatty acid homeostasis pathways. O. stamineus is significantly targeting many oxidative stress regulators, including JNK, mammalian target of rapamycin (mTOR), NFKB1, PPAR, and AKT1. Molecular docking analysis confirmed the expected high affinity for the potential targets, while the in vitro assay indicates the ability of O. stamineus to inhibit hepatic fat accumulation. Conclusion: Using the computational systems pharmacology approach, the potentially beneficial effect of O. stamineus in NAFLD was indicated through the combination of multiple compounds, multiple targets, and multicellular components.  相似文献   
3.
BackgroundThe association between systemic lupus erythematosus (SLE) and sarcoidosis has been considered as extremely rare. Most often, sarcoidosis coexists with Sjögren's syndrome. Researching the literature, it seems that the association of SLE and sarcoidosis is much more frequent than previously thought.Aim of the workWe present a case of a Serbian woman who was diagnosed with coexisting sarcoidosis and long-standing SLE.Case presentationThe 40 years old SLE patient was in long-standing remission on oral prednisolone (10 mg/day) and hydroxychloroquine (HCQ) (400 mg/day). She presented with fatigue, chest pain, and dry cough. Chest computerized tomography (CT) showed hilar and mediastinal lymphadenopathy. The biopsy had been performed and results showed sarcoidosis. Diagnosis has been confirmed: eosinophilic granulomas without central necrosis morphologically corresponding to chronic granulomatous lymphadenitis like sarcoidosis. Thereafter, the patient was hospitalized. No new symptoms appeared, and the physical examination was unremarkable. Serum calcium was elevated (2.75 mmol/l), anti-nuclear antibody (ANA), anti-double stranded deoxyribonucleic acid (anti-dsDNA) and anti-Ro antibodies were positive. Angiotensin converting enzyme (ACE) level was high normal (51 IU/L) and QuantiFERON-TB Gold test negative. The dose of prednisolone was increased to 40 mg/day with HCQ and the patient was discharged from hospital. On follow-up the patient improved with reduction of the steroid dose.ConclusionThe association of SLE and sarcoidosis should be considered even though it is reported to be extremely rare. May be the real incidence of these combinations is underestimated. More research about genetics and pathogenesis is needed to completely understand these conditions.  相似文献   
4.
5.
内生菌由细菌、真菌、古菌和原生生物组成,它们生活在植物的活体组织中,具有丰富的次级代谢产物多样性。人参内生菌在人参的生长发育、次级代谢产物的生成和环境适应等方面均有重要的促进作用,对人参的产量和品质有较大影响。随着人们在微生物领域研究的深入,高通量测序技术已经成为研究植物内生菌的重要方法。文章主要从人参内生菌分离与鉴定研究方法、人参内生菌的多样性、人参内生菌及其次级代谢产物的活性、人参内生菌对宿主的影响等4个方面对人参内生菌近年来的研究进展进行讨论,并对其发展方向提出展望,以期为药用植物内生菌研究和品质改良提供新思路、新方法。  相似文献   
6.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.  相似文献   
7.
8.
The emergence of carbapenem-resistant organisms posed considerable threat to global health while only limited treatment options are available and led to efforts to discover a novel way to treat them. To evaluate in vitro synergistic activity of meropenem plus ertapenem, a total of 203 carbapenem-resistant strains, collected from 12 provinces and municipalities in China, were examined with a dual carbapenem combination therapy. The statistical software R was used for analysis. Two hundred and one (201) of carbapenem-resistant strains mainly produced four types of carbapenemase: KPC-2 (n = 142, 69.95%), OXA-232 (n = 7, 3.45%), NDM (n = 38, 18.72%; 36 NDM-1, 1 NDM-4, 1 NDM-5), and IMP (n = 15, 7.39%; 1 IMP-26, 10 IMP-30, 4 IMP-4). Fifty-one out of two hundred and three (51/203 or 25.12%) of the examined strains showed a synergistic effect for the meropenem plus ertapenem combination throughout the checkerboard method, while only three isolates showed potential clinically relevant synergy (3/203, 1.48%). An additive effect was observed in 55/203 (27.09%) of the examined strains. Ninety-seven of the examined isolates (47.78%) showed fractional inhibitory concentration (FIC) greater or equal to 2 (indicating antagonism). The synergistic activity of meropenem plus ertapenem combination suggests this combination can be a possible way to treat the infection caused by the carbapenem-resistant organisms, especially for IMP or NDM producer with a lesser minimum inhibitory concentration (MIC) and the infected individual who was not recommended to use colistin or tigecycline.  相似文献   
9.
10.
IntroductionDetailed data on clinical characteristics in children with the omicron strain of SARS-COV-2 are limited.MethodsWe conducted a retrospective observational study of children with COVID-19 at the National Center for Child Health and Development to evaluate the clinical manifestations during and before the emergence of the omicron variant. Only symptomatic patients without underlying diseases were included. Participants were divided into two temporal groups: the “omicron era” (1/2022–2/2022) and the “pre-omicron era,” where the delta variant predominated (7/2021–11/2021). The patients were subclassified into an older vaccine-eligible group (aged 12–17 years), a younger vaccine-eligible group (aged 5–11 years), and a vaccine-ineligible group (aged 0–4 years).ResultsWe compared 113 patients in the omicron era with 106 in the pre-omicron era. Most patients in both eras had non-severe disease, and no patients required mechanical ventilation or died. Among patients aged 0–4 years, sore throat and hoarseness were more common during the omicron era than the pre-omicron era (11.1% vs. 0.0% and 11.1% vs. 1.5%, respectively). Croup syndrome was diagnosed in all patients with hoarseness. Among patients aged 5–11 years, vomiting was more frequent during the omicron era (47.2%) than during the pre-omicron era (21.7%). Cough and rhinorrhea were less common during the omicron era in patients aged 0–4 and 5–11 years, respectively, than during the pre-omicron era.ConclusionsIn children with COVID-19, clinical manifestations differed between the omicron and pre-omicron eras. In the Omicron era, croup syndrome was more frequent in vaccine-ineligible children.  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