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   4342篇
  免费   344篇
  国内免费   216篇
耳鼻咽喉   24篇
儿科学   57篇
妇产科学   42篇
基础医学   891篇
口腔科学   69篇
临床医学   287篇
内科学   730篇
皮肤病学   55篇
神经病学   323篇
特种医学   76篇
外科学   295篇
综合类   654篇
现状与发展   1篇
预防医学   88篇
眼科学   45篇
药学   768篇
  1篇
中国医学   174篇
肿瘤学   322篇
  2024年   3篇
  2023年   48篇
  2022年   70篇
  2021年   140篇
  2020年   96篇
  2019年   116篇
  2018年   96篇
  2017年   115篇
  2016年   126篇
  2015年   154篇
  2014年   230篇
  2013年   269篇
  2012年   255篇
  2011年   264篇
  2010年   222篇
  2009年   228篇
  2008年   250篇
  2007年   245篇
  2006年   198篇
  2005年   211篇
  2004年   217篇
  2003年   203篇
  2002年   195篇
  2001年   159篇
  2000年   143篇
  1999年   150篇
  1998年   111篇
  1997年   97篇
  1996年   75篇
  1995年   47篇
  1994年   37篇
  1993年   34篇
  1992年   21篇
  1991年   24篇
  1990年   13篇
  1989年   11篇
  1988年   3篇
  1987年   2篇
  1986年   6篇
  1985年   2篇
  1984年   6篇
  1982年   2篇
  1980年   4篇
  1979年   1篇
  1978年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有4902条查询结果,搜索用时 15 毫秒
1.
Mixed lineage leukemia 1(MLL1)是组蛋白甲基转移酶SET家族的成员之一。MLL1与WDR5、RbBP5、Ash2L和DPY-30组成MLL1甲基转移酶复合物调控组蛋白H3的第4位赖氨酸的甲基化水平,对造血系统的发育和血细胞的更新至关重要。部分白血病患者体内存在因MLL1基因易位而产生的致癌蛋白——MLL1融合蛋白,MLL1融合蛋白在发挥其致癌作用时需要功能完整的MLL1酶复合物,故靶向MLL1-WDR5的蛋白-蛋白相互作用成为治疗MLL1融合型白血病的潜在策略。本文对MLL1-WDR5蛋白-蛋白相互作用的生物学机制、结构信息以及抑制剂进行了系统的总结,并结合已报道数据对该领域进行了展望,以期为后续研究提供参考。  相似文献   
2.
目的:通过生物信息学技术比较哮喘患者与健康人的基因芯片数据,初步鉴定与哮喘相关的基因以及治疗哮喘的潜在药物。方法:从基因表达数据库下载GSE74986基因芯片,使用GEO2R分析得出差异表达基因,采用Morpheus制作差异表达基因的热图;通过DAVID 6.8对差异表达基因进行基因本体及京都基因与基因组百科全书分析,使用String 10.5构建蛋白质-蛋白质相互作用网络,筛选核心基因。进一步使用Cytoscape 3.6.1的插件MCODE对差异表达基因进行模块分析。通过医学本体信息检索平台筛选治疗哮喘的小分子药物。结果:筛选出510个差异表达基因,包括29个上调基因和481个下调基因。差异表达基因生物过程与通路主要富集在染色质沉默、核糖核酸聚合酶Ⅱ启动子的转录调节、蛋白质转运、信使核糖核酸加工、核糖核酸剪接以及泛素介导的蛋白水解、内质网中的蛋白质加工、核糖核酸转运、髓样分化因子依赖性Toll样受体信号通路、血小板激活、核苷酸结合寡聚化结构域样受体信号通路等。共得出9个核心基因,包括T-复合蛋白1θ亚基(CCT8),T复合物蛋白1α亚单位(TCP1),26S蛋白酶调节亚单位S10B(PSMC6),热休克蛋白90α(HSP90A) A1,细胞周期蛋白C(CCNC),HSP90AB1,26S蛋白酶体非ATP酶调节亚基6(PSMD6),泛素特异性蛋白酶14(USP14),真核细胞翻译起始因子4E(EIF4E)。得出2个重要模块,模块里的基因主要涉及剪接体和泛素介导的蛋白水解、蛋白修饰以及核糖核酸修饰等生物过程。治疗哮喘的潜在小分子药物有茴香霉素和金雀异黄素等。结论:差异表达基因和核心基因促进了对哮喘发病分子机制的理解,为哮喘的诊治提供了潜在的基因靶标与治疗药物。  相似文献   
3.
4.
目的:观察血府逐瘀汤合温胆汤加减联合西药治疗高血压颈动脉硬化的效果。方法:选取2017年6月至2018年6月聊城市中医院收治的高血压颈动脉硬化患者92例作为研究对象,按照随机数字表法随机分为对照组与观察组,每组46例。对照组患者给予左旋氨氯地平+阿托伐他汀口服,观察组在对照组基础上加用血府逐瘀汤合温胆汤加减口服。观察患者血压、血脂控制情况,测定颈动脉内膜中层厚度(IMT)、斑块面积、血管皮内皮功能、血清蛋白酶分子水平。结果:与对照组比较,观察组治疗后的血压SBP、DBP及血脂TG、TC、LDL-C等指标更低(P<0.05);颈动脉粥样硬化斑块IMT厚度、斑块面积明显缩小(P<0.05),血管内皮功能指标ET-1、AngⅡ、TXB2水平明显降低,NO水平明显升高(P<0.05);血清CatK、MMP-9水平明显降低(P<0.05);观察组不良反应发生率8.70%明显低于对照组不良反应发生率21.74%(P<0.05)。结论:血府逐瘀汤合温胆汤加减联合西药更利于控制高血压颈动脉硬化患者的血压,调节脂质代谢,改善血管内皮功能,降低血清蛋白酶分子的含量,用药安全。  相似文献   
5.
6.
Acetone cyanohydrin (ACH) is a readily available source of cyanide and is widely used in basic and applied sciences. In toxicology, ACH is classified as extremely hazardous as it readily decomposes on contact with water, with the potential rapid release of highly toxic hydrogen cyanide (HCN). We report the case of a young woman found dead from the intentional ingestion of ACH and citalopram, an antidepressant of the selective serotonin reuptake inhibitor class. The autopsy findings included bright reddish-purple hypostasis and mild pulmonary edema. As ACH can decompose to acetone and HCN, we quantified the concentration of each compound and thiocyanate separately in various body fluids and organs and determined their whole-body distributions by using gas chromatography–mass spectrometry (GC–MS). We observed high concentrations of both acetone and cyanide in the blood (0.63 mg/mL and 17.99 mM, respectively) and gastric contents (9.76 mg/mL and 472.44 mM). The whole-body distributions of acetone and cyanide were similar (i.e., the concentration of each compound was the highest in the lung, followed by the heart, and then the liver). Our results suggest that not only the route of administration but also the dose taken could greatly affect the body distributions of cyanide in humans. In addition, as toxicological screening detected citalopram, which was not prescribed to the deceased, we performed a chiral analysis by using liquid chromatography–tandem mass spectrometry (LC–MS/MS). We determined that only (S)-citalopram was ingested antemortem; its concentration was 0.36 μg/mL, which is in the toxic range.  相似文献   
7.
BackgroundMajor depressive disorder (MDD) is the leading cause of years lived with disability worldwide, and up to 40% of individuals with MDD do not respond to current treatments. Studies suggest that peripheral inflammation plays an important role in the striatal mesolimbic dopamine pathway and corticostriatal reward circuitry in MDD. Although MDD patients show blunted striatal responses to reward, the link between degree of inflammation and attenuation of reward processing is unclear. We investigated whether MDD patients with elevated peripheral inflammation exhibit attenuated reward responses to enhance our understanding of MDD pathophysiology and develop more effective treatments for current non-responders.MethodsMDD subjects varying on serum C-reactive protein (CRP) concentrations (MDD-High CRP, >3 mg/L, n = 44; MDD-Low CRP, <3 mg/L, n = 44) and healthy comparisons (HC, n = 44) completed a monetary incentive delay (MID) task and provided blood samples to measure inflammation-related markers. MDD-High and MDD-Low were propensity score-matched on age, sex, body mass index (BMI), smoking status, exercise and MID task head motion. Percent change in blood oxygen level-dependent (BOLD) signal during anticipation of wins and losses was extracted from bilateral nucleus accumbens, dorsal caudate and dorsolateral putamen regions of interest (ROIs). A linear mixed-effects model was used to test group (MDD-High, MDD-Low and HC), condition (large-win, small-win and no win), and their interaction for these ROIs as well as whole-brain voxelwise data. Analyses also tested group differences in inflammatory mediators. Correlations were used to explore the relationship between inflammatory mediators and brain regions showing differences between MDD-High and MDD-Low.ResultsMDD-High exhibited: (a) lower BOLD signal change in dorsal caudate, thalamus, left insula and left precuneus during anticipation of small wins than MDD-Low; and (b) higher serum soluble intercellular adhesion molecule 1 (sICAM-1) and interleukin 6 (IL-6) concentrations than MDD-Low and HC. MDD as a whole, regardless of CRP-based inflammation, exhibited: (a) lower precuneus BOLD signal change to large wins than HC; and (b) higher Interleukin 1 receptor antagonist (IL-1ra), macrophage-derived chemokine (MDC) and macrophage inflammatory protein-1 alpha (MIP-1α) concentrations than HC. Higher serum sICAM-1 concentrations were associated with lower caudate BOLD signal change to small wins only within the MDD-High group.ConclusionWithin MDD patients, high inflammation (CRP, sICAM-1) was linked to reduced striatal activation recruited to discriminate intermediate reward magnitudes. These findings support an association between levels of peripheral inflammation and the degree of reward-related activation in individuals with MDD.Registration of clinical trialsThe ClinicalTrials.gov identifier for the clinical protocol associated with data published in this current paper is NCT02450240, “Latent Structure of Multi-level Assessments and Predictors of Outcomes in Psychiatric Disorders.”  相似文献   
8.
9.
X-linked lymphoproliferative disease (XLP) is a rare immunodeficiency disease characterized by severe immune disorder and extreme vulnerability to Epstein-Barr virus (EBV) infections. Here we report a 14-month-old Chinese boy presenting with fulminant infectious mononucleosis (FIM) following EBV infection, and died of hepatic failure within one week of disease progression. Postmortem examination revealed icterus, ascites, extensive enlarged mesenteric lymph nodes and hepatosplenomegaly. Histopathological examination showed diffuse proliferation of cytotoxic T lymphoid cells and hemophagocytosis in multiple organs. The family history revealed his brother had died under similar circumstances at 5 five years of age. The cause of death of the boy was ascribed to XLP. To the best of our knowledge, there is few autopsy-confirmed XLP case in the forensic practice. The complicated manifestations and systemic pathological changes should be well recognized by clinicians and forensic pathologists.  相似文献   
10.
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