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   819篇
  免费   344篇
  国内免费   371篇
耳鼻咽喉   4篇
儿科学   51篇
妇产科学   82篇
基础医学   28篇
口腔科学   57篇
临床医学   186篇
内科学   134篇
皮肤病学   7篇
神经病学   14篇
特种医学   8篇
外科学   46篇
综合类   447篇
预防医学   41篇
眼科学   21篇
药学   119篇
  1篇
中国医学   168篇
肿瘤学   120篇
  2024年   4篇
  2023年   18篇
  2022年   82篇
  2021年   178篇
  2020年   265篇
  2019年   131篇
  2018年   151篇
  2017年   93篇
  2016年   86篇
  2015年   71篇
  2014年   38篇
  2013年   29篇
  2012年   38篇
  2011年   55篇
  2010年   69篇
  2009年   35篇
  2008年   23篇
  2007年   63篇
  2006年   41篇
  2005年   12篇
  2004年   8篇
  2003年   3篇
  2002年   6篇
  2001年   10篇
  2000年   3篇
  1999年   2篇
  1998年   12篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
排序方式: 共有1534条查询结果,搜索用时 15 毫秒
1.
A rapid and high selective ultra?performance liquid chromatography (UPLC) with tandem mass spectrometry method for simultaneous determination of six compounds including albiflorin, paeoniflorin, picroside I, picroside II, saikosaponin A, and saikosaponin D in rat plasma was developed and validated using butyl p-hydroxybenzoate as an internal standard. One-step direct protein precipitation with acetonitrile was used to extract the compounds from the rat plasma samples. Chromatographic separation was achieved using an ACQUITY UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 µm) at a flow rate of 0.4 mL/min, using gradient mode containing 0.1% formic acid in water and acetonitrile were used as the Mobile phase A and B. Electrospray ionization in negative ion mode and multiple reaction monitoring were used to identify and quantify active components. Calibration curves showed good linearity (R2 > 0.9908) over a wide concentration range for all compounds. The intra- and interday precision (relative standard deviation) ranged 2.4%–7.0% and 2.6%–8.0%, respectively. The accuracy (relative error) was from ?13.0% to 13.2% at all quality control levels. The recovery ranged from 81.1% to 92.5%. The validated method was successfully applied to pharmacokinetic study in rats after oral administration of Qing Gan?Shu Yu?Fang. The results show that one can draw a conclusion that these six active ingredients can be quickly absorbed and play a pharmacodynamic role rapidly in vivo.  相似文献   
2.
目的探讨基因间长链非编码RNA 152(LINC00152)靶向调控微小RNA-103a-3p(miR-103a-3p)表达及对非小细胞肺癌(NSCLC)细胞增殖和侵袭迁移的影响。方法采用实时定量PCR(QPCR)检测正常肺上皮细胞BEAS-2B及NSCLC细胞(ANIP-973、NCI-H157、A549和NCI-H1975)的LINC00152水平。选取LINC00152水平最高的细胞分别转染LINC00152特异性小干扰RNA(si-LINC00152组)或无关序列(si-NC组),另设未转染细胞为对照组。QPCR检测LINC00152水平,活细胞计数CCK-8法、Transwell小室和划痕实验测定细胞增殖、侵袭和迁移能力,Western blotting检测基质金属蛋白酶(MMP)-2、MMP-9和第10号染色体缺失的磷酸酶及张力蛋白同源基因(PTEN)的水平;荧光素酶报告实验验证LINC00152靶向结合miR-103a-3p的能力。结果NSCLC细胞的LINC00152水平均高于BEAS-2B细胞(P<0.05),尤其是NCI-H1975细胞的最高。si-LINC00152组的LINC00152水平为0.352±0.087,低于对照组的1.058±0.219和si-NC组的1.126±0.139(P<0.05)。与si-NC组和对照组相比,si-LINC00152组NCI-H1975细胞转染48、72 h的增殖活力下降(P<0.05);si-LINC00152组的划痕愈合率和穿膜细胞数分别为(27.386±2.428)%和(78.840±5.031)个,低于si-NC组的(77.675±4.803)%和(179.208±13.264)个及对照组的(76.371±5.385)%和(174.003±15.678)个(P<0.05);与si-NC组和对照组相比,si-LINC00152组的MMP-2和MMP-9水平均降低,而PTEN水平升高(P<0.05)。对照组和si-NC组上述指标的差异无统计学意义(P>0.05)。双荧光素酶报告分析证实,miR-103a-3p模拟物降低了野生型LINC00152的荧光素酶活性(P<0.05),但对突变型无影响(P>0.05)。结论LINC00152在NSCLC细胞中高表达并发挥促癌作用,与NSCLC的迁移侵袭密切相关,LINC00152与miR-103a-3p间的相互作用在NSCLC靶向治疗中有一定潜能。  相似文献   
3.
4.
Background: Sepsisis one of the mostserious complications and a leading cause of death in patients with coronavirus disease 2019 (COVID-19). In general, it isthe result of an unregulated inflammatory cascade such as a postinfection “cytokine storm.” The conventional treatment mainly relies on glucocorticoids, of which curative effects are not ideal, as they come with significant side effects. It is critical to seek or develop other effective therapeutics in dealing cytokine storm to fight COVID-19 with sepsis. Aims and Objectives: Raise awareness of the significance applying anti-inflammatory acupuncture in dealing COVID-19 patients with sepsis and provide an appropriate acupuncture protocol that can be easily integrated into existing medical guideline. Materials and Methods: Current evidences from animal experiments and clinical trials about acupuncture in treating infectious sepsis are reviewed, and a detailed discussion on advantages of anti?inflammatory acupuncture is followed, then the rationality on the point selection and stimulation parameters of acupuncture is analyzed to propose an appropriate acupuncture protocol. Results: Current experiments have shown that acupuncture can play a significant role to improve inflammation reaction and reduce mortality in infectious animal and patients with sepsis and its mechanisms are mainly achieved by stimulating the vagus?cholinergic anti?inflammatory pathways.Applying acupuncture in treating COVID-19 patients with sepsis hasfour aspects of advantages. Moreover, a simple and convenient clinical acupuncture protocol including point selection and appropriate stimulation parameters is proposed. Conclusion: Acupuncture, especially electroacupuncture, has shown potentials in effectively treating infectious sepsis of animal models and critically ill patients in small sample studies by stimulating the nervous system, but has been largely overlooked in the clinic so far. It is advised that acupuncture should be integrated into the existing medical guidelines in dealing with COVID-19 complicated with sepsis.  相似文献   
5.
Numerous molecular mechanisms are being examined in an attempt to discover disease-modifying drugs to slow down the underlying neurodegeneration in Alzheimer’s disease.Recent studies have shown the beneficial effects of epidermal growth factor receptor inhibitors on the enhancement of behavioral and pathological sequelae in Alzheimer’s disease.Despite the promising effects of epidermal growth factor receptor inhibitors in Alzheimer’s disease,there is no irrefutable neuroprotective evidence in well-established animal models using epidermal growth factor receptor inhibitors due to many un-explored downstream signaling pathways.This caused controversy about the potential involvement of epidermal growth factor receptor inhibitors in any prospective clinical trial.In this review,the mystery beyond the under-investigation of epidermal growth factor receptor in Alzheimer’s disease will be discussed.Furthermore,their molecular mechanisms in neurodegeneration will be explained.Also,we will shed light on SARS-COVID-19 induced neurological manifestations mediated by epidermal growth factor modulation.Finally,we will discuss future perspectives and under-examined epidermal growth factor receptor downstream signaling pathways that warrant more exploration.We conclude that epidermal growth factor receptor inhibitors are novel effective therapeutic approaches that require further research in attempts to be repositioned in the delay of Alzheimer’s disease progression.  相似文献   
6.
ness58-60F832.49;F293.3J145;J159;J162;15;22;23;245;J;J162_22;J162_23;J145_15;J159_245;丁锴;0004001100030005;56-58税收筹划的经济学分析朱荣喜;上海视野经济研究所 税收筹划项目经理、注册会计师税收筹划是企业利润管理的重要手段,是企业财务管理行为和政府政策之间的最佳结合点,其经济学意义重大。一、税收筹划存在  相似文献   
7.
目的:探讨小檗碱对人乳腺癌细胞MDA-MB-231体外生长的影响及其与PPAR-y受体的关系.方法:采用噻唑蓝(MTT)法检测小檗碱对MDA-MB-231细胞的生长抑制效应;TUNEL法检测细胞凋亡;联合PPAR-γ拮抗剂GW9662,分析小檗碱对MDA-MB-231细胞增殖的影响与PPARγ受体的关系.结果:小檗碱呈量-效和时-效关系抑制MDA-MB-231细胞生长,24 h的半数抑制浓度(IC50)为0.21μmol/L;小檗碱诱导MDA-MB-231细胞凋亡作用随药物浓度的增加而增强;PPARγ受体拮抗剂不能逆转小檗碱对细胞增殖的抑制作用.结论:小檗碱可明显抑制MDA-MB-231细胞生长并诱导其凋亡,但其作用不通过PPAR受体介导.  相似文献   
8.
夏爱雪,秋爱露。冬占有了世界,那是多么美富的世界啊!然它很烦闷,因为它看不见一朵花。到不可忍耐的时候,冬把它的所有让给了0散文诗4I227.9F08353F;F083_53高长虹;1怀念叶子花盛; 甘肃临潭县石门梁家坡学校,1 花开花落,我飞翔的双翼如凋零的花瓣,轻轻地被风送回地面。潮起潮  相似文献   
9.
以<中国生物医学文献光盘数据库>(CBMdisc)收录在1982-1997年国内公开发行的专业期刊上发表的生物医学论文为基础,对以武汉总医院为第一著者单位发表的论文进行统计分析,以期从文献学的角度反映我院学术水平和发展动态,为医学科研管理提供参考信息.  相似文献   
10.
目的:建立山东省正常?少年儿童X线头影测量Steiner分析法的均值和标准差,并研究其颅面结构的性别差异、地域差异及增龄性变化。方法:按正常?标准选择156名山东省正常?少年儿童,拍摄X线头颅定位侧位片,采用Steiner分析法进行定点及测量,进行男女间,替牙期与恒牙初期之间的比较。并与哈尔滨和广州地区恒牙初期儿童正常值比较。结果:得到了山东省正常?少年儿童Steiner分析法的正常值;女性下颌骨整体有后缩趋势,男性从替牙期到恒牙初期?平面倾斜度变缓;与哈尔滨人相比,山东人的上颌相对前突;而与广州人相比,广州人的双颌更加前突。结论:用Steiner分析法测得的正常值男女间、替牙期与恒牙期之间均存在差别,不同地区人群头影测量值也存在差别。  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