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   250297篇
  免费   19649篇
  国内免费   7261篇
耳鼻咽喉   1830篇
儿科学   9439篇
妇产科学   2431篇
基础医学   22648篇
口腔科学   4499篇
临床医学   25990篇
内科学   60676篇
皮肤病学   3343篇
神经病学   28824篇
特种医学   7116篇
外国民族医学   12篇
外科学   20761篇
综合类   31949篇
现状与发展   33篇
一般理论   13篇
预防医学   19839篇
眼科学   3351篇
药学   17445篇
  198篇
中国医学   11239篇
肿瘤学   5571篇
  2024年   232篇
  2023年   4898篇
  2022年   6684篇
  2021年   12383篇
  2020年   12347篇
  2019年   10983篇
  2018年   10646篇
  2017年   9663篇
  2016年   9504篇
  2015年   9329篇
  2014年   17978篇
  2013年   20158篇
  2012年   14867篇
  2011年   16127篇
  2010年   12372篇
  2009年   11785篇
  2008年   11712篇
  2007年   11053篇
  2006年   9708篇
  2005年   8104篇
  2004年   6975篇
  2003年   5997篇
  2002年   5004篇
  2001年   4343篇
  2000年   3708篇
  1999年   3032篇
  1998年   2611篇
  1997年   2272篇
  1996年   1981篇
  1995年   2083篇
  1994年   1931篇
  1993年   1627篇
  1992年   1521篇
  1991年   1366篇
  1990年   1098篇
  1989年   933篇
  1988年   862篇
  1987年   787篇
  1986年   679篇
  1985年   1236篇
  1984年   1161篇
  1983年   742篇
  1982年   884篇
  1981年   760篇
  1980年   602篇
  1979年   544篇
  1978年   439篇
  1977年   367篇
  1976年   336篇
  1975年   275篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
21.
《Cancer radiothérapie》2022,26(3):502-516
The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients’ evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients’ quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.  相似文献   
22.
23.
24.
对间歇性禁食法的概念、方法及形式、历史发展以及在糖尿病前期及糖尿病病人中的应用效果等进行介绍,阐述间歇性禁食法研究现状,总结间歇性禁食法对糖尿病前期和糖尿病病人的有益影响。  相似文献   
25.
26.
Gestational alloimmune liver disease (GALD) is a materno-fetal alloimmune disorder that targets the fetal liver and often causes neonatal liver failure. GALD most commonly presents as neonatal hemochromatosis (NH), which is a severe neonatal liver injury confirmed by extra-hepatic iron accumulation at various sites. With the discovery of the alloimmune mechanism of GALD, exchange transfusion and intravenous immunoglobulin (IVIG) administration are being used as novel treatments. Here, we present a rare case of an 11-day-old female infant who presented with marked hyperbilirubinemia. Laboratory findings showed significantly elevated direct and indirect bilirubin, high ferritin and alpha fetoprotein levels, high transferrin saturation, and severe coagulopathy. Abdominal magnetic resonance imaging revealed markedly reduced T2 signal intensity in the liver and pancreas compared to the spleen, suggesting iron deposition. The infant was diagnosed with NH and successfully treated with exchange transfusion and four doses of IVIG.  相似文献   
27.
28.
ObjectivePrevious epidemiologic studies have suggested an association between appendectomy and Parkinson's disease. The aim of the current study was to examine the risk of Alzheimer's disease (AD) and other types of dementia following appendicitis or appendectomy for appendicitis.DesignPopulation-based cohort study.Setting and participantsWe used claims data from the Taiwan National Health Insurance Research Database. Participants aged ≥45 years with acute appendicitis or who received appendectomy for appendicitis were enrolled and followed up for more than 15 years. Cases and controls underwent 1:1 matching by age, sex, index date, and dementia-related comorbidities.MethodsThe primary outcome was AD, and secondary outcomes included other dementia types. Adjusted hazard ratios (aHRs) were calculated, and a competing risk regression model was created. The E value for causality of evidence was calculated.ResultsPatients developing appendicitis (0.6% vs 0.1%, P = .005) and those receiving appendectomy for appendicitis (0.4% vs 0.1%, P = .003) had higher incidences of AD than the controls during the follow-up period. A Cox regression analysis with adjustment for potential confounders showed that patients with appendicitis [aHR 6.68, 95% confidence interval (CI) 1.84-24.48] and those receiving appendectomy for appendicitis (aHR 5.01, 95% CI 1.33-18.85) were more likely to develop AD than the controls. These 2 groups also had higher risks for unspecified dementia and all types of dementia but not for vascular dementia than the controls. The age at dementia diagnosis was 88.51 years in the controls; however, among people who developed dementia following appendicitis, the mean age at diagnosis was 70.18 years, and dementia occurred 5.84 years after appendicitis. The competing risk regression models and the E values support the study findings.Conclusions and implicationsAfter recovery from appendicitis, these patients should be followed up for signs of AD.  相似文献   
29.
The objective of the present study was the development and validation of the method for determining AMB-FUBINACA and its metabolite - AMB-FUBINACA O-desmethyl acid – in blood samples, followed by verification of the method in toxicological judicial and forensic medicine practice employing the example of post-aggression suicide. Most likely in consequence of development of adverse effects resulting in psychotic symptoms, a male being under the influence of the synthetic cannabinoid AMB-FUBINACA and the new synthetic opioid U-47700, mortally wounded his female partner and subsequently committed suicide. Identification and determination of the afore-mentioned xenobiotics in blood samples collected from the male and female victims were performed employing high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The analytes were isolated from blood samples using the solid phase extraction (SPE) method. The blood samples collected from the male and female demonstrated respectively 110 and 196 ng/mL of AMB-FUBINACA O-desmethyl acid metabolite, 1935 and 357 ng/mL of U-47700, 250 and 200 ng/mL of N-desmethyl-U-47700, as well as 410 and 200 ng/mL of N,N-didesmethyl-U-47700. The concentration values of new psychoactive substances (NPS’s) in blood samples originating from the male and female were within the ranges encountered in cases of poisoning, including these resulting in death. Nevertheless, the evident signs of exsanguination proof that the woman was alive when she sustained lethal injuries. The presented cases illustrate the difficult to be anticipated effect exerted on the users by NPS’s.  相似文献   
30.
《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   
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