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   1414篇
  免费   147篇
  国内免费   36篇
耳鼻咽喉   14篇
儿科学   19篇
妇产科学   29篇
基础医学   178篇
口腔科学   48篇
临床医学   130篇
内科学   119篇
皮肤病学   31篇
神经病学   124篇
特种医学   60篇
外国民族医学   1篇
外科学   144篇
综合类   227篇
预防医学   141篇
眼科学   56篇
药学   62篇
中国医学   79篇
肿瘤学   135篇
  2024年   1篇
  2023年   23篇
  2022年   47篇
  2021年   76篇
  2020年   57篇
  2019年   64篇
  2018年   64篇
  2017年   56篇
  2016年   75篇
  2015年   46篇
  2014年   100篇
  2013年   84篇
  2012年   74篇
  2011年   74篇
  2010年   69篇
  2009年   63篇
  2008年   63篇
  2007年   83篇
  2006年   73篇
  2005年   51篇
  2004年   57篇
  2003年   29篇
  2002年   35篇
  2001年   31篇
  2000年   20篇
  1999年   21篇
  1998年   22篇
  1997年   13篇
  1996年   13篇
  1995年   17篇
  1994年   14篇
  1993年   7篇
  1992年   8篇
  1991年   8篇
  1990年   5篇
  1989年   6篇
  1988年   6篇
  1987年   3篇
  1986年   7篇
  1985年   8篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   5篇
  1980年   3篇
  1979年   3篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1973年   3篇
排序方式: 共有1597条查询结果,搜索用时 15 毫秒
1.
BackgroundThis study aimed to investigate the incidence and distribution of regional lymph node metastasis according to tumor location, and to clarify whether tumor location could determine the extent of regional lymphadenectomy in patients with pathological T2 (pT2) gallbladder carcinoma.MethodsIn total, 81 patients with pT2 gallbladder carcinoma (25 with pT2a tumors and 56 with pT2b tumors) who underwent radical resection were enrolled. Tumor location was determined histologically in each gallbladder specimen.ResultsSurvival after resection was significantly worse in patients with pT2b tumors than those with pT2a tumors (5-year survival, 72% vs. 96%; p = 0.027). Tumor location was an independent prognostic factor on multivariate analysis (hazard ratio, 14.162; p = 0.018). The incidence of regional lymph node metastasis was significantly higher in patients with pT2b tumors than in those with pT2a tumors (46% vs. 20%; p = 0.028). However, the number of positive nodes was similar between the two groups (median, 2 vs. 2; p = 0.910). For node-positive patients with pT2b tumors, metastasis was found in every regional node group (12%–63%), whereas even for node-positive patients with pT2a tumors, metastasis was observed in regional node groups outside the hepatoduodenal ligament.ConclusionsTumor location in patients with pT2 gallbladder carcinoma can predict the presence or absence of regional lymph node metastasis but not the number and anatomical distribution of positive regional lymph nodes. The extent of regional lymphadenectomy should not be changed even in patients with pT2a tumors, provided that they are fit enough for surgery.  相似文献   
2.
3.
We studied the prognostic value of primary tumor sidedness in metastatic colorectal cancer over time and across treatment lines. Population data on synchronous metastatic colorectal cancer patients were extracted from the Netherlands Cancer Registry and SEER database. Pubmed, EMBASE and Cochrane library were searched for prospective studies on metastatic colorectal cancer to conduct a meta-analysis. Inclusion criteria consisted of metastatic disease, systemic treatment with palliative intent and specification of primary tumor location. Data were pooled using a random-effects model. For the population-based data, multivariable Cox models were constructed. The Grambsch-Therneau test was conducted to evaluate the potential time-varying nature of sidedness. Meta-regression incorporating treatment-line as variable was conducted to test the pre-specified hypothesis that the prognostic value of sidedness varies over time. Analysis of 12 885 and 16 160 synchronous metastatic colorectal cancer patients registered in the Netherlands Cancer Registry and SEER database, respectively, indicated a time-varying prognostic value of sidedness (P < .01). Thirty-one studies were selected for the meta-analysis (9558 patients for overall survival analysis). Pooled univariable hazard ratioleft-sided/right-sided for overall survival was 0.71 (95% CI: 0.65-0.76) in 1st-line, 0.76 (0.54-1.06) in 2nd-line and 1.01 (0.86-1.19) in 3rd-line studies. Hazard ratios were significantly influenced by treatment line (P = .035). The prognostic value of sidedness of the primary tumor in metastatic colorectal cancer patients treated with palliative systemic therapy decreases over time since diagnosis, suggesting that sidedness may not be a useful stratification factor in late-line trials. This decrease in prognostic value should be taken into account when providing prognostic information to patients.  相似文献   
4.
目的 探究原发灶定位与甲状腺乳头状微小癌(PTMC)颈侧区淋巴结转移的关系,评估超声检查预测颈侧区淋巴结转移的准确率。方法 回顾性分析2014年1月至2015年12月天津医科大学肿瘤医院收治的134例PTMC病人的临床资料,均行中央区淋巴结清扫+改良颈侧区淋巴结清扫。依据超声定位分组,分析癌灶位置与颈侧区淋巴结转移的关系。结果 颈侧各分区淋巴结转移发生率分别为:Ⅱ区30.6%、Ⅲ区50.7%、Ⅳ区57.5%、Ⅴ区11.3%。癌灶位于中上极者颈侧区淋巴结转移发生率高于癌灶位于下极者(89.7% vs. 75.7%,P=0.038),靠近外侧者较内侧者更易出现颈侧区淋巴结转移(93.7% vs. 81.4%,P=0.049)。超声检查判定Ⅱ、Ⅲ、Ⅳ、Ⅴ区淋巴结转移的敏感度分别为43.9%、85.3%、85.7%、14.3%;特异度为91.4%、57.6%、35.1%、99.1%。超声预测Ⅲ、Ⅳ区淋巴结转移敏感度较高,Ⅱ、Ⅴ区淋巴结转移特异度较高。结论 癌灶位置与甲状腺微小癌颈侧区淋巴结转移密切相关,超声可为临床确定颈侧区淋巴结的清扫范围提供依据。  相似文献   
5.
This study examined the criterion validity of self-reported running-related injuries (RRI) by novice runners. Fifty-eight participants (41 females; age 46 ± 11 yrs) of the “Start-to-Run” program provided self-reports on their RRIs using an online questionnaire. Subsequently, they attended injury consultations with sports medicine physicians who provided physician-reports (blinded for the self-reports) as a reference standard. Self-reports and physician-reports included information on injury location (i.e., hip/groin, upper leg, knee, lower leg, and ankle/foot) and injury type (i.e., muscle-tendon unit, joint, ligament, or bone). Sensitivity, specificity, and positive predictive values were 100% for all five injury locations. For injury type, sensitivity was low (66% for muscle-tendon unit, 50% for ligament, and 40% for bone) and lowest for joint injuries (17%). In conclusion, the validity of self-reported RRIs by novice runners is good for injury locations but not for injury types. In particular for joint injuries, the validity of novice runners’ self-reports is low.

Abbreviations: RRI: Running Related Injury; SMC: Sports Medicine Centre; MTU: Muscle Tendon Unit; PPV: Positive Predictive Value  相似文献   

6.
The location and angle of scaphoid fractures are important attributes which guide management. We used a 3 dimensional scaphoid model, generated from CT scans, to map scaphoid fracture planes. The point at which the fracture plane crossed the central axis of the scaphoid was noted. The angle of the fracture planes with regard to the central axis was also noted. This allowed calculation of the location of the fracture and the angle of the 379 fractures. The mean point of intersection for fractures with the scaphoid axis was 50% along the scaphoid. Sixty percent of all fractures were found around the central 20% of the scaphoid. The mean angle between the scaphoid axis and the fracture plane was 63 degrees). On comparing angle with location, as fractures move away from the scaphoid waist, they become less perpendicular to the scaphoid axis (p?p?p?p?=?.018). There was no link between fracture plane angles and age, sex and union status. Most fractures occur at the centre of the scaphoid. There is a link between the location and angle of scaphoid fractures. It also identifies older patients and males are more likely to have more proximal scaphoid fractures.  相似文献   
7.
李丹  邵祥芸  赵敏 《环球中医药》2020,13(3):384-388
目的基于文献研究,探讨失眠症的中医证候要素分布规律。方法通过检索中国知网数据库(CNKI)、万方数据库、维普全文期刊数据库2009年1月至2018年12月中医药期刊文献所报道的治疗失眠症相关文献,收集统计失眠症中医证候并提取证素信息,利用SPSS 23.0软件进行统计描述分析。结果(1)共检出文献653篇,符合要求317篇,整理后规范证名得到44种中医证候,其中以心脾两虚证、痰热内扰证、肝郁化火证、阴虚火旺证、心肾不交证等频次较高。(2)证素组合规律中以两证素、三证素、四证素组合为主。(3)在单一病性证素中以热(火)、气虚、血虚、阴虚等频次较高;病位证素以肝、心、脾、肾等频次较高。(4)在证素组合时以热(火)+肝、气虚+血虚+心+脾、热(火)+痰、热(火)+阴虚等频次较高。结论失眠症的主要病理因素以热(火)、气虚、血虚、阴虚为主,病位主要以肝、心、脾、肾为主。  相似文献   
8.
9.
When designing and interpreting results from clinical trials evaluating treatments for children on the autism spectrum, a complicating factor is that most children receive a range of concurrent treatments. Thus, it is important to better understand the types and hours of interventions that participants typically receive as part of standard of care, as well as to understand the child, family, and geographic factors that are associated with different patterns of service utilization. In this multi-site study, we interviewed 280 caregivers of 6-to-11-year-old school-aged children on the autism spectrum about the types and amounts of interventions their children received in the prior 6 weeks. Reported interventions were coded as “evidence-based practice” or “other interventions,” reflecting the level of empirical support. Results indicated that children received a variety of interventions with varying levels of empirical evidence and a wide range of hours (0–79.3 h/week). Children with higher autism symptom levels, living in particular states, and who identified as non-Hispanic received more evidence-based intervention hours. Higher parental education level related to more hours of other interventions. Children who were younger, had lower cognitive ability, and with higher autism symptom levels received a greater variety of interventions overall. Thus, based on our findings, it would seem prudent when designing clinical trials to take into consideration a variety of factors including autism symptom levels, age, cognitive ability, ethnicity, parent education and geographic location. Future research should continue to investigate the ethnic, racial, and socioeconomic influences on school-aged intervention services.  相似文献   
10.
目的探讨卒中类型、卒中部位与卒中后癫痫的多因素关系,为卒中后癫痫的防治提供参考。方法以1804例卒中患者为研究对象,收集其性别、年龄、卒中类型、卒中部位、卒中后癫痫发生的时间等资料,根据卒中后是否发生癫痫,将患者分为卒中后无癫痫组(n=1487)和卒中后癫痫组(n=317),分析卒中后癫痫发作的危险因素。结果共317例卒中后癫痫发作患者,其中早发性癫痫141例(44.48%),迟发性癫痫176例(55.52%)。不同卒中部位及卒中类型的癫痫发病率为17.57%。多因素logistic回归分析显示,卒中部位中的顶叶合并蛛网膜下腔、额叶合并颞叶、额叶合并颞叶和枕叶、单一颞叶是卒中后发生癫痫的危险因素(P<0.01),其中单一颞叶是卒中后早发性癫痫的危险因素(P<0.01)。脑梗死患者常见早发性癫痫(23.66%),脑出血患者常见迟发性癫痫(47.95%)。结论卒中类型中的脑梗死、脑出血、蛛网膜下腔出血与卒中后癫痫有关;卒中部位中顶叶合并蛛网膜下腔、额叶合并颞叶、额叶合并颞叶和枕叶、单一颞叶与卒中后癫痫有关。  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