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   4893篇
  免费   561篇
  国内免费   349篇
耳鼻咽喉   59篇
儿科学   34篇
妇产科学   42篇
基础医学   549篇
口腔科学   47篇
临床医学   758篇
内科学   659篇
皮肤病学   81篇
神经病学   253篇
特种医学   195篇
外科学   478篇
综合类   772篇
现状与发展   2篇
一般理论   1篇
预防医学   383篇
眼科学   148篇
药学   567篇
  4篇
中国医学   322篇
肿瘤学   449篇
  2024年   11篇
  2023年   95篇
  2022年   153篇
  2021年   276篇
  2020年   238篇
  2019年   220篇
  2018年   203篇
  2017年   177篇
  2016年   180篇
  2015年   267篇
  2014年   354篇
  2013年   238篇
  2012年   394篇
  2011年   387篇
  2010年   257篇
  2009年   197篇
  2008年   294篇
  2007年   276篇
  2006年   222篇
  2005年   235篇
  2004年   129篇
  2003年   114篇
  2002年   132篇
  2001年   88篇
  2000年   99篇
  1999年   119篇
  1998年   87篇
  1997年   73篇
  1996年   60篇
  1995年   44篇
  1994年   43篇
  1993年   18篇
  1992年   27篇
  1991年   17篇
  1990年   21篇
  1989年   13篇
  1988年   12篇
  1987年   8篇
  1986年   9篇
  1985年   6篇
  1984年   1篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
排序方式: 共有5803条查询结果,搜索用时 31 毫秒
91.
Objective: This prospective study tested the hypothesis that psychological dysregulation in mid-adolescence (age 16) mediates the association between parent-child attachment in late childhood (age 10–12) and development of substance use disorder (SUD) in adulthood (age 22). Method: The Youth Attachment to Parents Scale (YAPS) was developed in 10–12-year-old boys and girls (N?=?694) at baseline residing in western Pennsylvania. Psychological dysregulation was measured by the neurobehavior disinhibition trait. Substance use was assessed at ages 10–12, 12–14, 16 and 19. SUD was diagnosed at age 22 using the Structured Clinical Interview for DSM Disorders. The mediation of parent-child attachment and SUD by neurobehavior disinhibition was tested separately for mothers and fathers while controlling for baseline substance use. Results: Psychological dysregulation mediates the association between attachment to mothers and SUD, and partially mediates the association between attachment to fathers and SUD. Significant mediation effects remains after controlling for baseline substance use. Conclusion: Optimal prevention of SUD should include ameliorating both psychological dysregulation predisposing to SUD and quality of the parent-child relationship.  相似文献   
92.
目的探讨心血管内科医护人员的焦虑状况。方法采用焦虑自评量表(self-rating anxiety scale,SAS)对98名心血管内科医护人员进行问卷调查,并与国内常模比较。了解心血管内科医护人员焦虑状况。结果非焦虑者35名,占35.7%,焦虑者63名,占64.3%;心血管内科医护人员焦虑水平明显高于国内常模(P<0.05);心血管内科护士焦虑水平明显高于医生(P<0.05)。结论心血管医务人员心理健康状况与医疗职业特点密切相关,医护人员焦虑水平明显高于国内常模,护士焦虑水平明显高于医生,应切实提高其心理应对能力。  相似文献   
93.
目的了解0~6岁儿童口腔颌面部外伤的特点,为预防口腔颌面部外伤提供参考。方法对2009~2010年在我院口腔科因口腔颌面外伤就诊的472例患者按照年龄、性别、外伤原因、外伤部位、外伤类型以及治疗方法进行回顾性分析。结果 0~6岁儿童口腔颌面部外伤发生率男女比例为1.55:1;1~3岁组外伤发生率高于0~1岁组和3~6岁组;跌倒是造成外伤的主要原因;外伤最易出现部位为唇部。结论掌握儿童口腔颌面部外伤的特点,采取有效的预防措施,可以减少口腔颌面部外伤的发生。  相似文献   
94.
Melatonin confers cardioprotective effect against myocardial ischemia/reperfusion (MI/R) injury by reducing oxidative stress. Activation of silent information regulator 1 (SIRT1) signaling also reduces MI/R injury. We hypothesize that melatonin may protect against MI/R injury by activating SIRT1 signaling. This study investigated the protective effect of melatonin treatment on MI/R heart and elucidated its potential mechanisms. Rats were exposed to melatonin treatment in the presence or the absence of the melatonin receptor antagonist luzindole or SIRT1 inhibitor EX527 and then subjected to MI/R operation. Melatonin conferred a cardioprotective effect by improving postischemic cardiac function, decreasing infarct size, reducing apoptotic index, diminishing serum creatine kinase and lactate dehydrogenase release, upregulating SIRT1, Bcl‐2 expression and downregulating Bax, caspase‐3 and cleaved caspase‐3 expression. Melatonin treatment also resulted in reduced myocardium superoxide generation, gp91phox expression, malondialdehyde level, and increased myocardium superoxide dismutase (SOD) level, which indicate that the MI/R‐induced oxidative stress was significantly attenuated. However, these protective effects were blocked by EX527 or luzindole, indicating that SIRT1 signaling and melatonin receptor may be specifically involved in these effects. In summary, our results demonstrate that melatonin treatment attenuates MI/R injury by reducing oxidative stress damage via activation of SIRT1 signaling in a receptor‐dependent manner.  相似文献   
95.
The purpose of this study was to provide a simulation therapy environment for microwave thermal ablation (MWA) under the guidance of ultrasound, and to present an inexpensive and portable simulator built on real patient-based pre-operative computed tomography (CT) data. We established an experimental simulation system for teaching MWA and present the results of a preliminary evaluation of the simulator’s realism and utility for training. The system comprises physical elements of an electromagnetic tracking device and an abdominal phantom, and software elements providing three-dimensional (3D) image processing tools, real-time navigation functions and objective evaluation function module. Details of the novel aspects of this system are presented, including a portable electromagnetic tracking device, adoption of real patient-based pre-operative CT data of liver, operation simulation of MWA, and recording and playback of the operation simulation. Patients with liver cancer were selected for evaluation of the clinical application value of the experimental simulation system. A total of 50 consultant interventional radiologists and 20 specialist registrars in radiology rated the simulator’s hardware reality and overall ergonomics. Results show that the simulator system we describe can be used as a training tool for MWA. It enables training with real patient cases prior to surgery, and it can provide a realistic simulation of the actual procedure.  相似文献   
96.
Zhai S  Zhuang Y  Song Y  Li S  Huang D  Kang W  Li X  Liao Q  Liu Y  Zhao Z  Lu Y  Sun Y 《Current HIV research》2008,6(4):335-350
To assess the immunodominance patterns of HIV-1-specific cytotoxic T lymphocyte (CTL) responses and the contribution of these responses against the peptides scanning optimal epitopes in chronic infection, we test the HIV-1-specific CTL responses against a panel of 413 overlapping peptides spanning HIV-1 Asian B sequence, including 147 peptides corresponding to optimal clade B epitopes in 49 chronically HIV-1 infected individuals by interferon-gamma Elispot assay. A large variation in the recognition of peptides restricted by the same HLA class I allele is presented. Some epitopes are targeted frequently by individuals while other epitopes restricted by the same allele are rarely recognized in our research. HLA-B35 and HLA-A03 rather than other HLA alleles contribute greatly to total virus-specific CTL responses. Furthermore, there is a significant inverse correlation between the total contribution of HIV-1-specific CTL responses restricted by different HLA alleles to virus-specific immune responses and viral load in the individuals during advanced infection (P=0.002, r=-0.549). The peptides targeted by individuals have significantly lower entropy compared with those not targeted but restricted by the same HLA class I alleles (P<0.05) in 49 individuals infected by HIV-1, especially the advanced infection subgroup (P=0.044). These data demonstrate that the consistent immunodominance patterns of HIV-1-specific CTL responses of Chinese HIV-1 infected individuals and an inverse correlation between the relative contribution of responses restricted by HLA alleles and viral load, which indicates the important protective effect of optimal epitopes against slow disease progression even in advanced infection.  相似文献   
97.
摘 要 目的:系统评价万古霉素首剂给予负荷剂量对患者临床结局的影响。方法:系统检索英文数据库PubMed,Embase,Cochrane Library,中文数据库CNKI,WanFang,CBM,纳入所有关于万古霉素首剂给予负荷剂量的研究。结局指标为感染治疗的有效率、目标浓度的达标率和肾毒性的发生率。结果:纳入1篇随机对照试验,2篇队列研究,共199名患者,其中1篇研究报道负荷剂量可以提高感染治疗的有效率[RR=1.27,95%CI(0.97,1.67),P>0.05],2篇研究报道负荷剂量可以提高目标浓度的达标率[RR=1.54,95%CI (0.72,3.30),P>0.05],1篇研究报道负荷剂量组与对照组的肾毒性发生率[RR=3.87,95%CI(0.46,32.57),P>0.05]。结论:万古霉素首剂给予负荷剂量可以提高感染治疗的有效率和目标浓度的达标率,但未显示出临床优势。  相似文献   
98.
目的 探讨基孔肯雅热临床特点及治疗与转归.方法 选取2010年9月至2010年11月东莞市诊治的133例基孔肯雅热患者为研究对象,所有患者行3年随访,分析其临床特征及治疗与预后.结果 基孔肯雅热病常见临床症状为发热、皮疹及关节疼痛,发生率分别为100.00%、91.72%和90.98%;关节疼痛中膝关节、脚踝及肘部关节受累较多,发生率分别为69.92%、64.66%和48.87%;关节疼痛女性明显多于男性,15岁以上患者易发生关节疼痛;关节疼痛症状在1年内基本消失,部分患者在2年甚至3年内消失,个别患者在3年后仍未消失.结论 基孔肯雅热病主要以发热、皮疹及关节痛为主要临床表现,关节疼痛受年龄等因素影响,治疗后1年患者内关节疼痛基本可消失,对症、支持治疗对基孔肯雅热有显著治疗效果.  相似文献   
99.
100.
To investigate the relationship between the changes in circulating CD45RO+T lymphocyte subsets following neoadjuvant therapy for rectal cancer in patients with locally advanced rectal cancer.The clinicopathological data of 185 patients with rectal cancer who received neoadjuvant therapy in the General Surgery Department of Beijing Chaoyang Hospital affiliated to Capital Medical University from June 2015 to June 2017 were analyzed. Venous blood samples were collected 1 week before neoadjuvant therapy and 1 week before surgery, and the expression of CD45RO+T was detected by flow cytometry. The receiver operating characteristic curve analysis was used to determine the optimal cut-off point of CD45RO+ratio. Log-rank test and multivariate Cox regression were used to analyze the overall survival rate (OS) and disease-free survival rate (DFS) associated with CD45RO+ratio.Circulating CD45RO+ratio of 1.07 was determined as the optimal cut-off point and CD45RO+ratio-high was associated with lower tumor regression grade grading (P = .031), T stage (P = .001), and tumor node metastasis (TNM) stage (P = .012). The 3-year DFS and OS rate in the CD45RO+ratio-high group was significantly higher than that in the CD45RO+ratio-low group (89.2% vs 60.1%, P<.001; 94.4% vs 73.2%, P<.001). The multivariate Cox analysis revealed that elevated CD45RO+ratio was an independent factor for better DFS (OR, 0.339; 95% CI, 0.153–0.752; P = .008) and OS (OR, 0.244; 95% CI,0.082–0.726; P = .011).Circulating CD45RO+ratio could predict the tumor regression grade of neoadjuvant therapy for rectal cancer, as well as long-term prognosis. These findings could be used to stratify patients and develop alternative strategies for adjuvant therapy.  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