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   9722篇
  免费   920篇
  国内免费   177篇
耳鼻咽喉   50篇
儿科学   254篇
妇产科学   81篇
基础医学   1707篇
口腔科学   101篇
临床医学   803篇
内科学   1168篇
皮肤病学   46篇
神经病学   1150篇
特种医学   104篇
外科学   386篇
综合类   506篇
现状与发展   2篇
预防医学   924篇
眼科学   107篇
药学   2727篇
  6篇
中国医学   318篇
肿瘤学   379篇
  2023年   154篇
  2022年   197篇
  2021年   364篇
  2020年   380篇
  2019年   383篇
  2018年   362篇
  2017年   345篇
  2016年   373篇
  2015年   372篇
  2014年   559篇
  2013年   860篇
  2012年   518篇
  2011年   534篇
  2010年   443篇
  2009年   491篇
  2008年   467篇
  2007年   398篇
  2006年   330篇
  2005年   299篇
  2004年   254篇
  2003年   233篇
  2002年   176篇
  2001年   146篇
  2000年   151篇
  1999年   157篇
  1998年   102篇
  1997年   95篇
  1996年   108篇
  1995年   100篇
  1994年   96篇
  1993年   114篇
  1992年   102篇
  1991年   101篇
  1990年   105篇
  1989年   83篇
  1988年   83篇
  1987年   80篇
  1986年   78篇
  1985年   92篇
  1984年   84篇
  1983年   47篇
  1982年   68篇
  1981年   60篇
  1980年   52篇
  1979年   42篇
  1978年   33篇
  1977年   31篇
  1976年   42篇
  1975年   23篇
  1974年   14篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Children with autism spectrum disorder (ASD) demonstrate limited playfulness. Their difficulty engaging in meaningful interaction with others renders playful engagement in social interactions a challenge. Although little direct evidence exists regarding the promotion of these children’s playful engagement, links can be established with many traits cited in play and social interaction studies. This paper presents the results of a conceptual clarification exercise regarding the key behaviours associated with the construct of playful engagement in preschool-aged children with ASD. Behaviours were identified based on hallmark deficits in early social interactions and play of children with ASD. The analysis revealed the following behaviours: positive affect, engagement, imitation, joint attention, initiation of social interaction, social responsiveness, flexibility, child’s laughter in funny situations and giving and reading non-verbal cues. In conclusion, a conceptually coherent stage has been set for exploring the literature regarding interventions to promote the playful engagement of preschool-aged children with ASD.  相似文献   
33.
《Injury》2019,50(4):834-847
The use of suture associated with heterologous fibrin sealant has been highlighted for reconstruction after peripheral nerve injury, having the advantage of being safe for clinical use. In this study we compared the use of this sealant associated with reduced number of stitches with conventional suture after ischiatic nerve injury. 36 Wistar rats were divided into 4 groups: Control (C), Denervated (D), ischiatic nerve neurotmesis (6 mm gap); Suture (S), epineural anastomosis after 7 days from neurotmesis, Suture + Fibrin Sealant (SFS), anastomosis with only one suture point associated with Fibrin Sealant. Catwalk, electromyography, ischiatic and tibial nerve, soleus muscle morphological and morphometric analyses were performed. The amplitude and latency values of the Suture and Suture + Fibrin Sealant groups were similar and indicative of nerve regeneration.The ischiatic nerve morphometric analysis in the Suture + Fibrin Sealant showed superior values related to axons and nerve fibers area and diameter when compared to Suture group. In the Suture and Suture + Fibrin Sealant groups, there was an increase in muscle weight and in fast fibers frequency, it was a decrease in the percentage of collagen compared to group Denervated and in the neuromuscular junctions, the synaptic boutons were reestablished.The results suggest a protective effect at the lesion site caused by the fibrin sealant use. The stitches reduction minimizes the trauma caused by the needle and it accelerates the surgical practice. So the heterologous fibrin sealant use in nerve reconstruction should be considered.  相似文献   
34.

Background

First-line adjuvant chemotherapy options for early-stage colorectal cancer (CRC) include CapeOx (capecitabine, intravenous oxaliplatin) and FOLFOX (intravenous 5-fluorouracil, leucovorin, oxaliplatin). Capecitabine is an oral prodrug analog of 5-fluorouracil, and recent studies have suggested that proton pump inhibitors (PPIs) may detrimentally affect capecitabine efficacy. Conversely, some literature suggests that PPIs may negatively affect CRC itself. To gain insight into the nature of PPIs’ effect on capecitabine and CRC, we investigated their effects on effectiveness of CapeOx versus FOLFOX chemotherapy.

Patients and Methods

We conducted a retrospective chart review of 389 patients with stage II-III CRC who received adjuvant CapeOx or FOLFOX from 2004 to 2013. Information regarding PPI receipt, chemotherapy, and patient outcomes from medical records was analyzed.

Results

Three-year recurrence-free survival was significantly lower in CapeOx-treated PPI recipients than non-PPI recipients (69.5 vs. 82.6%; P = .029). Unadjusted analysis showed that CapeOx-treated PPI recipients were twice as likely to experience cancer recurrence or death as CapeOx-treated non-PPI recipients (hazard ratio = 2.03; 95% confidence interval, 1.06-3.88; P = .033). FOLFOX-treated PPI recipients had a non–statistically significant difference in 3-year recurrence-free survival versus non-PPI recipients (82.9 vs. 61.7%; P = .066) and a non–statistically significant difference in recurrence/death (hazard ratio = 0.51; 95% confidence interval, 0.25-1.06; P = .071). No significant differences were seen in overall survival between groups.

Conclusion

Our results suggest PPIs negatively affected recurrence-free survival in CapeOx-treated CRC patients and yielded no significant effects among FOLFOX-treated patients, potentially implicating a pharmacokinetic interaction between PPIs and capecitabine. No overall survival effects were seen. Given PPIs’ widespread use, further studies are required to corroborate our findings.  相似文献   
35.
Modes of interactions of small ligands with CYP3A4 have been defined using the Template established in our previous studies (DMPK. 34: 113–125 2019 and 34 351–364 2019). Interactions of polyaromatic hydrocarbons such as benzo[a]pyrene, pyrene and dibenzo[a,j]acridine were refined with the idea of Right-side movement of ligands at Rings A and B of Template. Expected formation of metabolites from the placements faithfully matched with experimentally observed sites of their metabolisms and also with preferred orders of regio-isomeric metabolite abundances in recombinant CYP3A4 system. In comparison of CYP3A4-ligand data with the placements on simulations, a futile sitting of non-substituted and free rotatable phenyl structures was suggested as a cause of poor oxidations of the phenyl parts of CYP3A4 ligands. These data were in turn indicative of the role of the rotation-ceasing action for the function. Typical inhibitors, ketoconazole, nicardipine, mibefradil and GF-I-1 shared mutuality on their sittings, in which the inhibitor molecules hold a CYP3A4 residue from dual sides on Template. In addition, clotrimazole would be stuck between facial- and rear-side walls of CYP3A4 and interact with ferric iron through nitrogen atom of the imidazole part. These data offered structural bases of CYP3A4-inhibitory actions of ligands.  相似文献   
36.
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   
37.
38.
39.
40.
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