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   67063篇
  免费   8889篇
  国内免费   1766篇
耳鼻咽喉   424篇
儿科学   1235篇
妇产科学   798篇
基础医学   4032篇
口腔科学   2565篇
临床医学   12492篇
内科学   6562篇
皮肤病学   835篇
神经病学   3688篇
特种医学   1981篇
外国民族医学   9篇
外科学   6516篇
综合类   12253篇
一般理论   29篇
预防医学   6734篇
眼科学   941篇
药学   7237篇
  656篇
中国医学   5873篇
肿瘤学   2858篇
  2024年   118篇
  2023年   1616篇
  2022年   2163篇
  2021年   3888篇
  2020年   4680篇
  2019年   3266篇
  2018年   3007篇
  2017年   3500篇
  2016年   3296篇
  2015年   2838篇
  2014年   5372篇
  2013年   5943篇
  2012年   4525篇
  2011年   4585篇
  2010年   3599篇
  2009年   3146篇
  2008年   3020篇
  2007年   3028篇
  2006年   2571篇
  2005年   2130篇
  2004年   1813篇
  2003年   1611篇
  2002年   1275篇
  2001年   1018篇
  2000年   806篇
  1999年   597篇
  1998年   494篇
  1997年   460篇
  1996年   414篇
  1995年   340篇
  1994年   332篇
  1993年   244篇
  1992年   295篇
  1991年   217篇
  1990年   193篇
  1989年   178篇
  1988年   171篇
  1987年   152篇
  1986年   105篇
  1985年   118篇
  1984年   119篇
  1983年   67篇
  1982年   71篇
  1981年   63篇
  1980年   57篇
  1979年   40篇
  1978年   29篇
  1977年   32篇
  1976年   27篇
  1975年   32篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
目的 探讨不同时期慢性阻塞性肺疾病(COPD)患者血清诱饵受体3(DcR3)、凋亡抑制蛋白(Survivin)表达水平及临床意义。方法 选取2018年9月—2019年12月本院收治的92名COPD患者为研究对象,其中稳定型COPD 50例,急性加重期COPD 42例;同期本院健康体检者88例为对照组。测定各组研究对象血清DcR3、Survivin水平及肺功能指标。 与对照组[DcR3(106.54±48.35)pg/mL,Survivin(98.85±26.59)pg/mL]比较,稳定期组和急性加重期组血清DcR3[(395.23±123.85)pg/mL,(1 248.81±213.59)pg/mL]、Survivin [(267.54±84.69)pg/mL,(1 233.95±307.26)pg/mL]水平升高;与稳定期组比较,急性加重期组血清DcR3、Survivin水平升高。与对照组比较,稳定期组和急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001);与稳定期组比较,急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001)。随着低氧血症严重程度的增加,COPD患者血清DcR3、Survivin水平逐渐增加(P<0.001)。多因素logistics回归分析显示,高水平DcR3、Survivin、IL-12、hs-CRP为COPD病情的危险因素(P<0.001)。DcR3、Survivin与FEV、FEV1 /FVC呈负相关,与IL-12、TNF-α、hs-CRP呈正相关(P<0.001)。 COPD稳定期、急性加重期患者血清DcR3、Survivin表达水平升高,且DcR3、Survivin与COPD病情严重程度呈正相关。  相似文献   
2.
3.
In Abram Brummett and Erica K. Salter's excellent paper, “Mapping the Moral Terrain of Clinical Deception,” they rightly note that it is sometimes ethically appropriate for health care professionals to deceive patients and families. However, they also note that because doing so violates a prima facie duty of honesty, the ethical burden of proof falls upon the deceiver. Hence, they also provide a sophisticated framework for determining whether any given case is warranted. I applaud their overall approach but also critique some of their claims, in particular, their conclusion that lies of commission require greater justification than those of omission and their conflation of the principles of beneficence and nonmaleficence. I also urge them to give greater attention to how power asymmetries should be accounted for and to the impact such deceptive choices might have on the clinician's character.  相似文献   
4.
5.
Minimally invasive approaches are increasingly being applied in surgeries and have recently been used in living donor hepatectomy. We have developed a safe and reproducible method for minimally invasive living donor liver transplantation, which consists of pure laparoscopic explant hepatectomy and pure laparoscopic implantation of the graft, which was inserted through a suprapubic incision. Pure laparoscopic explant hepatectomy without liver fragmentation was performed in a 60-year-old man with alcoholic liver cirrhosis and hepatocellular carcinoma. The explanted liver was retrieved through a suprapubic incision. A modified right liver graft, procured from his 24-year-old son using the pure laparoscopic method, was inserted through a suprapubic incision, and implantation was performed intracorporeally throughout the procedure. The time required to remove the liver was 369 min, and the total operative time was 960 min. No complications occurred during or after the surgery. The patient recovered well, and his hospital stay was of 11 days. Pure laparoscopic living donor liver transplantation from explant hepatectomy to implantation was performed successfully. It is a feasible procedure when performed by a highly experienced surgeon and transplantation team. Further studies with larger sample sizes are needed to confirm its safety and feasibility.

  相似文献   

6.

Background

Survival in cancer patients is associated with a multitude of biological, social, and psychological factors. Although it is well established that all these factors add to overall mortality, it is not well understood how the predictive power of these parameters changes in a comprehensive model and over time.

Methods

Patients who attended the authors’ outpatient clinic were invited to participate. The authors followed 5180 mixed cancer patients (51.1% female; mean age, 59.1 years [SD = 13.8]) for up to 16 years and analyzed biological (age, sex, cancer site, anemia), psychological (anxiety, depression), and social variables (marital status, education, employment status) potentially predicting overall survival in a Cox proportional hazards model.

Results

The median survival time for the entire sample was 4.3 years (95% confidence interval, 4.0–4.7). The overall survival probabilities for 1 and 10 years were 76.8% and 38.0%, respectively. Following an empirical approach, the authors split the time interval into five periods: acute, subacute, short-term, medium-term, and long-term. A complex pattern of variables predicted overall survival differently in the five periods. Biological parameters were important throughout most of the time, social parameters were either time-independent predictors or tended to be more important in the longer term. Of the psychological parameters, only depression was a significant predictor and lost its predictive power in the long-term.

Conclusions

The findings of this study allow the development of comprehensive patient-specific models of risk and resilience factors addressing biopsychosocial needs of cancer patients, paving the way for a personalized treatment plan that goes beyond biomedical cancer care.  相似文献   
7.
目的 探究注意缺陷多动障碍(ADHD)患儿血清25羟基维生素D[25(OH)D]、微量元素表达水平及临床意义。方法 选取2019年4月至2020年11月本院诊治的84例ADHD患儿进行研究(ADHD组),依据ADHD分型标准将患儿分为注意缺陷为主型组(28例)、多动为主型组(33例)、混合型组(23例),并选取同期84例体检健康儿童进行对照研究(对照组)。采用高效液相色谱-串联质谱法检测所有受试儿童血清25(OH)D水平;检测血清铁(Fe)、磷(P)、镁(Mg)、钙(Ca)、铜(Cu)、锌(Zn)、铅(Pb)水平;Pearson法分析ADHD患儿血清25(OH)D水平与Cu、Zn、Pb水平的相关性;Logistic回归分析ADHD发生的影响因素;受试者工作特征(ROC)曲线分析血清25(OH)D、Zn、Pb水平对ADHD的诊断价值。结果 ADHD组血清25(OH)D、Cu、Zn水平均显著低于对照组(P<0.05),Pb水平显著高于对照组(P<0.05);注意缺陷为主型组、多动为主型组、混合型组患儿血清25(OH)D、Fe、P、Mg、Ca、Cu、Zn、Pb水平比较,差异无统计学意义(P>0.05);ADHD患儿血清25(OH)D水平与Cu、Zn水平均呈正相关(P<0.05),与Pb水平呈负相关(P<0.05);25(OH)D、Zn是影响ADHD发生的保护因素(P<0.05),Pb是影响ADHD发生的危险因素(P<0.05);血清25(OH)D、Zn、Pb水平诊断ADHD的曲线下面积(AUC)分别为0.773、0.770、0.772,截断值分别为21.01 ng/mL、16.05 μmol/L、50.69 μg/L,相应灵敏度分别为82.1%、77.4%、63.1%,特异度分别为67.9%、71.4%、88.1%;三者联合诊断ADHD的AUC为0.883,其灵敏度、特异度分别为81.0%、81.0%。结论 ADHD患儿血清25(OH)D、Cu、Zn水平降低,Pb水平升高,25(OH)D、微量元素水平与ADHD患儿类型无关,25(OH)D、Zn、Pb联合有助于临床筛查ADHD患儿。  相似文献   
8.
PurposeTo evaluate the effectiveness and safety of fluoroscopy-guided percutaneous high ligation (FPHL) combined with fluoroscopy-guided foam sclerotherapy (FGFS) to treat varicose veins of the great saphenous veins (GSVs).Materials and MethodsThis was a retrospective study of 113 patients (mean age, 62.1 ± 10.8 years; 60 men) with varicose veins of the GSVs (133 limbs) that were treated with FPHL combined with FGFS between April 1 and October 31, 2019. Demographic and clinical data were collected from these patients before the FPHL procedure, after which FGFS was performed. The preterminal GSV was ligated percutaneously by a percutaneously-positioned polypropylene ligature under fluoroscopic guidance. The outcome of ligation was confirmed by venography. Then, foam sclerotherapy was performed under fluoroscopy. At 1-year follow-up, GSV occlusion was evaluated by ultrasound. The venous clinical severity scores (VCSSs) were compared between the preoperative and 1-year follow-up periods.ResultsThe technical success rate was 100% (133 limbs). Complete 12-month follow-up was available for 112 limbs (84.2%) and 103 of these limbs (92.0%) remained occluded during this period. The VCSS improved from 4.71 ± 2.15 to 0.74 ± 0.60 (V = 6328, P < .001). During follow-up, there were 16 limbs with thrombophlebitis and 38 limbs with saphenous junction pain; these events were alleviated within 2 weeks of the procedure. There was no deep venous thrombosis or other severe adverse events.ConclusionsFPHL combined with FGFS to treat varicose veins in the GSVs achieved an occlusion rate of 92% and improved the clinical symptoms within 1 year; this minimally-invasive procedure was safe and effective.  相似文献   
9.
《Radiography》2022,28(3):793-797
IntroductionChanging working practices, student numbers, workforce demands, and deficits, have created a need to consider new ways of radiography student training. One suggestion could be to implement Peer Assisted Learning (PAL) during clinical placements. PAL utilises social constructivist theories, where peer tutors teach lower or same level tutees, reinforcing and practicing material formally taught. The aim of this study was to trial an intervention of PAL, co-designed between the university and students and evaluated to identify opportunities and challenges.MethodsUsing participatory action research 8 final year student volunteers trialled a 3-week intervention, where they delivered PAL to first years, tutoring on first year radiographic clinical practice. Focus groups were held pre and post intervention to gather qualitative data.ResultsFocus group discussions were transcribed and collectively thematically analysed. Two students and the primary researcher took part in the analysis.ConclusionStudents identified benefits and challenges to PAL. Issue around preparing for and being a peer tutor are also discussed.Further study involving experiences of first year students and clinical colleagues is required.Implications for practicePeer-tutoring has potential benefits to students to facilitate the development of skills related to image analysis and critique as well as radiographic anatomy and patient positioning.  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