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   52437篇
  免费   4441篇
  国内免费   2405篇
耳鼻咽喉   537篇
儿科学   808篇
妇产科学   534篇
基础医学   6330篇
口腔科学   951篇
临床医学   6030篇
内科学   7731篇
皮肤病学   971篇
神经病学   2709篇
特种医学   2597篇
外国民族医学   7篇
外科学   5157篇
综合类   7262篇
现状与发展   11篇
一般理论   3篇
预防医学   4104篇
眼科学   1041篇
药学   5712篇
  36篇
中国医学   2896篇
肿瘤学   3856篇
  2024年   147篇
  2023年   609篇
  2022年   1678篇
  2021年   2347篇
  2020年   1622篇
  2019年   1482篇
  2018年   1600篇
  2017年   1592篇
  2016年   1707篇
  2015年   2644篇
  2014年   3136篇
  2013年   3513篇
  2012年   4839篇
  2011年   5006篇
  2010年   3480篇
  2009年   2834篇
  2008年   3393篇
  2007年   3233篇
  2006年   2837篇
  2005年   2497篇
  2004年   1902篇
  2003年   1806篇
  2002年   1521篇
  2001年   998篇
  2000年   767篇
  1999年   487篇
  1998年   311篇
  1997年   244篇
  1996年   182篇
  1995年   155篇
  1994年   136篇
  1993年   87篇
  1992年   110篇
  1991年   79篇
  1990年   51篇
  1989年   45篇
  1988年   31篇
  1987年   31篇
  1986年   26篇
  1985年   14篇
  1984年   12篇
  1983年   10篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   21篇
  1977年   5篇
  1976年   8篇
  1970年   4篇
  1969年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
目的 通过扎根理论研究构建患者视角的预检分诊服务满意度理论框架,为评估和量化患者对预检分诊服务的满意度提供参考。方法 采用目的抽样和理论抽样的方法,选择27例接受过预检分诊服务的患者进行半结构式深度访谈;运用程序化扎根理论的研究方法,采用NVIVO12.0软件辅助对原始数据进行开放式编码、主轴编码及选择性编码,并进行理论饱和度检验。结果 析出患者期望、服务质量、信息供给、人本关怀、持续改进5个主范畴。结论 5个主范畴分别构成预检分诊服务满意度的主体因素、核心因素、关键因素、基本因素和保障因素。该理论框架可为改善预检分诊服务、评估患者满意度提供参考。  相似文献   
102.
BACKGROUNDThe cardiovascular hazards of total homocysteine (tHcy) are long known. In addition, despite the acknowledgment on the importance of low ankle-brachial index (ABI) (< 0.9), borderline ABI (0.91-0.99) was once commonly overlooked. This study aims to explore the independent and joint effect of tHcy level and borderline ABI on all-cause death in hypertensive population.METHODSThis study included 10,538 participants from China H-type Hypertension Registry Study. ABI was described into two groups: normal ABI (1.00-1.40) and borderline ABI. tHcy level was also divided into two groups: < 15.02 and ≥ 15.02 μmo/L. Four groups were analyzed, using COX proportional hazard regression model, separately and pairwise to observe the independent and joint effect on all-cause death.RESULTSA total of 126 (1.2%) deaths were observed in the 1.7 years follow-up time. Borderline ABI has a higher predicted risk of death than normal ABI (HR = 1.87, 95%CI: 1.17-3.00) after adjusting for potential covariates. Compare with tHcy level < 15.02 μmo/L (low tHcy), those with tHcy ≥ 15.02 μmo/L (high tHcy) had higher risk to event outcome (HR = 1.99, 95% CI: 1.30-3.05). According to the cumulative hazard curve, group with borderline ABI and high tHcy level has significantly higher altitude and larger increasing rate over follow-up period compare to other groups. Among those with borderline ABI, participants with high tHcy had higher death risk than those with low tHcy, nevertheless, no significant different between borderline and normal ABI among those with low tHcy levels.CONCLUSIONSBorderline ABI and tHcy level both have independent predictive value on all-cause death. The combined group of borderline ABI and high tHcy has highest risk factor of outcomes, which suggested the mutual additive value of borderline ABI and tHcy. More attention should be given to the importance of borderline ABI in hypertensive population, especially with elevated tHcy level.

Homocysteine (Hcy) is a sulfur-containing, non-proteinogenic amino acid synthesized through the transmethylation of amino acid methionine from one-carbon metabolism. Elevated plasma total homocysteine (tHcy) level is associated with endothelial dysfunction, increased blood coagulation, and metabolic disturbance, promoting cardiovascular diseases, stroke, and coronary artery disease.[1,2] Notably, patients with high Hcy levels and concomitant hypertension were suggested to be at particularly higher risk.[3] Moreover, increasing studies have explored a positive association between advanced Hcy level with all-cause mortality. According to a recent dose-response meta-analysis, for each 5-μmol/L increment of tHcy levels, the risk for all-cause mortality increased by 33.6%.[4]The ankle-brachial index (ABI) is an effective, well-established measure that is commonly used in the diagnosis of peripheral artery disease (PAD),[5] meanwhile was well studied as an important indicator of atherosclerosis and CVD events.[6] Although ankle-brachial index (ABI) ≤ 0.90 has been recognized as the threshold value for abnormal/low ABI, which was proven to increase the risk of all-cause mortality,[7] a study from the American Heart Association has suggested ABI between 0.91 and 1.00 should be considered as “borderline area” in terms of cardiovascular risks,[8] considering of prior probability and sensitivity of ABI calculation. Emerging studies have aimed to explore the predictive value of borderline ABI,[9-11] however, controversy remains because of limited and inconsistent data. The current study aimed to explore the individual and joint effect of borderline ABI and tHcy on all-cause mortality among hypertensive adults. Although ABI level ≤ 0.90 has been and is going to remain significant in clinical practice, we believe broader concern should be placed on borderline ABI, especially for its value in risk differentiation and identification. To the best of our knowledge, there are no similar previous studies.  相似文献   
103.
The Epstein–Barr virus (EBV) can cause different types of cancer in human beings when the virus infects different cell types with various latent patterns. EBV shapes a distinct and immunosuppressive tumor microenvironment (TME) to its benefit by influencing and interacting with different components in the TME. Different EBV-associated malignancies adopt similar but slightly specific immunosuppressive mechanisms by encoding different EBV products to escape both innate and adaptive immune responses. Strategies reversing the immunosuppressive TME of EBV-associated malignancies have been under evaluation in clinical practice. As the interactions among EBV, tumor cells, and TME are intricate, in this review, we mainly discuss the epidemiology of EBV, the life cycle of EBV, the cellular and molecular composition of TME, and a landscape of different EBV-associated malignancies and immunotherapy by targeting the TME.  相似文献   
104.
BACKGROUND/OBJECTIVESZanthoxylum schinifolium is traditionally used as a spice for cooking in East Asian countries. This study was undertaken to evaluate the anti-proliferative potential of ethanol extracts of Z. schinifolium leaves (EEZS) against human bladder cancer T24 cells.MATERIALS/METHODSSubsequent to measuring the cytotoxicity of EEZS, the anti-cancer activity was measured by assessing apoptosis induction, reactive oxygen species (ROS) generation, and mitochondrial membrane potential (MMP). In addition, we determined the underlying mechanism of EEZS-induced apoptosis through various assays, including Western blot analysis.RESULTSEEZS treatment concentration-dependently inhibited T24 cell survival, which is associated with apoptosis induction. Exposure to EEZS induced the expression of Fas and Fas-ligand, activated caspases, and subsequently resulted to cleavage of poly (ADP-ribose) polymerase. EEZS also enhanced the expression of cytochrome c in the cytoplasm by suppressing MMP, following increase in the ratio of Bax:Bcl-2 expression and truncation of Bid. However, EEZS-mediated growth inhibition and apoptosis were significantly diminished by a pan-caspase inhibitor. Moreover, EEZS inhibited activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway, and the apoptosis-inducing potential of EEZS was promoted in the presence of PI3K/Akt inhibitor. In addition, EEZS enhanced the production of ROS, whereas N-acetyl cysteine (NAC), a ROS scavenger, markedly suppressed growth inhibition and inactivation of the PI3K/Akt signaling pathway induced by EEZS. Furthermore, NAC significantly attenuated the EEZS-induced apoptosis and reduction of cell viability.CONCLUSIONSTaken together, our results indicate that exposure to EEZS exhibits anti-cancer activity in T24 bladder cancer cells through ROS-dependent induction of apoptosis and inactivation of the PI3K/Akt signaling pathway.  相似文献   
105.
106.
扶正消瘤液对肿瘤化疗增敏作用的临床研究   总被引:6,自引:0,他引:6  
观察中药复方在肿瘤化疗增敏方面的作用。将 6 9例晚期肿瘤患者随机分为治疗组和对照组 ,治疗组用中药复方扶正消瘤液配合化疗进行临床治疗 ,并与单纯化疗组进行对照。两组化疗方法相同。结果 ,治疗组有效率为 31.5 8% ,对照组有效率为 2 2 .5 8% ,统计学处理差异明显 (P<0 .0 5 )。治疗组治疗前后 TL c TR、NKc A、s IL-2 R及对照组治疗后相比均有显著性差异。结论 ,中药复方扶正消瘤液对晚期肿瘤化疗有一定的增敏作用。  相似文献   
107.
麝香酮对氰化钠加缺糖致PC12细胞缺血损伤的保护作用   总被引:2,自引:1,他引:2  
目的:研究麝香酮对PC12细胞缺血损伤的影响。方法:在离体培养的PC12细胞,用NaCN加缺糖造成拟缺血损伤模型,通过细胞形态学观察、MTT微量比色、培养介质LDH活力测定,研究了麝香酮对该模型的保护作用。结果:10-7~510-5mol/L范围内,麝香酮呈浓度依赖性地降低NaCN加缺糖造成拟缺血损伤模型培养介质内LDH的释放,其IC50为:43.33μmol/L。在10-7~510-5mol/L范围内,麝香酮呈浓度依赖性地增加NaCN加缺糖造成拟缺血损伤模型培养介质的MTT比色值,其IC50为30.62μmol/L。结论:麝香酮对PC12细胞缺血损伤具有保护作用。  相似文献   
108.
罗云  孙桂波  秦蒙  姚帆  孙晓波 《中国中药杂志》2012,37(22):3345-3349
细胞共培养由于能更好地模拟体内环境,便于更好的观察细胞与细胞、细胞与培养环境之间的相互作用以及探讨药物的作用机制和可能的作用靶点,填补了单层细胞培养与整体动物实验研究的鸿沟,近年来倍受医药领域的关注,成为药物研发、生物制药领域的研究热点.细胞共培养方法包括直接共培养和间接共培养,主要用于疾病病理基础、新型治疗手段以及药物活性筛选的研究.现有的细胞共培养技术主要用于单一药物的药效学研究,用于联合药物相互作用的研究甚少.中药复方之间协同配伍,减毒增效.细胞共培养技术符合中药多成分、多靶点的作用特点,这对于未来探讨中药联合用药对机体的作用及机制的研究具有一定参考价值,为中药及复方研究提供了一种新的手段.该文就细胞共培养技术的方法与运用进行了概述,并对该技术运用于中药及复方的研究进行了展望.  相似文献   
109.
中药复方研发成果与日俱增,而成果的专利保护状况却不容乐观.中药复方专利保护与中药新药研发、产业发展、中药国际化等诸多领域息息相关,促成中药复方研发与专利保护的协调发展对于国内乃至国际社会影响深远.  相似文献   
110.
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