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   58165篇
  免费   5216篇
  国内免费   3874篇
耳鼻咽喉   540篇
儿科学   735篇
妇产科学   461篇
基础医学   5180篇
口腔科学   1460篇
临床医学   7219篇
内科学   6585篇
皮肤病学   693篇
神经病学   2430篇
特种医学   2702篇
外国民族医学   24篇
外科学   7047篇
综合类   12554篇
现状与发展   13篇
一般理论   8篇
预防医学   4772篇
眼科学   1109篇
药学   6038篇
  54篇
中国医学   3813篇
肿瘤学   3818篇
  2024年   184篇
  2023年   664篇
  2022年   1598篇
  2021年   2514篇
  2020年   2100篇
  2019年   1516篇
  2018年   1669篇
  2017年   1697篇
  2016年   1465篇
  2015年   2498篇
  2014年   3398篇
  2013年   3603篇
  2012年   5126篇
  2011年   5551篇
  2010年   4423篇
  2009年   3874篇
  2008年   4044篇
  2007年   3764篇
  2006年   3673篇
  2005年   3121篇
  2004年   2192篇
  2003年   1825篇
  2002年   1507篇
  2001年   996篇
  2000年   892篇
  1999年   737篇
  1998年   418篇
  1997年   409篇
  1996年   278篇
  1995年   256篇
  1994年   244篇
  1993年   160篇
  1992年   150篇
  1991年   125篇
  1990年   94篇
  1989年   90篇
  1988年   66篇
  1987年   53篇
  1986年   51篇
  1985年   26篇
  1984年   28篇
  1983年   20篇
  1982年   14篇
  1981年   11篇
  1980年   15篇
  1979年   18篇
  1978年   11篇
  1977年   10篇
  1973年   10篇
  1965年   8篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
In clinical and epidemiological studies, there is a growing interest in studying the heterogeneity among patients based on longitudinal characteristics to identify subtypes of the study population. Compared to clustering a single longitudinal marker, simultaneously clustering multiple longitudinal markers allow additional information to be incorporated into the clustering process, which reveals co-existing longitudinal patterns and generates deeper biological insight. In the current study, we propose a Bayesian consensus clustering (BCC) model for multivariate longitudinal data. Instead of arriving at a single overall clustering, the proposed model allows each marker to follow marker-specific local clustering and these local clusterings are aggregated to find a global (consensus) clustering. To estimate the posterior distribution of model parameters, a Gibbs sampling algorithm is proposed. We apply our proposed model to the primary biliary cirrhosis study to identify patient subtypes that may be associated with their prognosis. We also perform simulation studies to compare the clustering performance between the proposed model and existing models under several scenarios. The results demonstrate that the proposed BCC model serves as a useful tool for clustering multivariate longitudinal data.  相似文献   
2.
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments.  相似文献   
3.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
4.
The research and development of penicillin started with difficulty before 1949 and achieved certain results. In 1951, after the founding of the People's Republic of China, Zhang Weishen, as the only Chinese scientist who had been trained and worked in a penicillin research and development center in the United States for many years, overcame many difficulties and returned to China. In 1953, with the efforts of Zhang Weishen and his colleagues, China realized the industrialized production of penicillin, alleviating the urgent needs of the masses. Antibiotics has also become the first discipline to achieve major scientific and technological achievements after the founding of the New China. In the mid-1950s, the technical breakthrough in the localization of lactose substitutes marked the localization of the raw materials of the penicillin-producing culture medium, which paved the way for the industrialized production of penicillin with Chinese characteristics. Antibiotics have become one of the most widely used and affordable drugs for hundreds of millions of patients in China, and China has since ended the humiliating history of the “Sick Man of East Asia".  相似文献   
5.
目的研究腹腔镜经脐单一部位幽门环肌切开术治疗小儿先天性肥厚性幽门狭窄的临床效果。方法100例小儿先天性肥厚性幽门狭窄患儿作为研究对象,按照随机方式分为观察组和对照组,每组50例。对照组采用腹腔镜幽门环肌切开术治疗,观察组采用腹腔镜经脐单一部位幽门环肌切开术治疗。观察记录患儿的手术结果及随访结果,并比较两组患儿手术时间、术后住院时间。结果手术过程顺利,100例患儿均成功完成手术,无一例中转开腹手术,无并发症发生。观察组患儿术后6 h将胃管取下,少量喂入温水后逐渐过渡到喂糖水、喂奶;对照组患儿术后24 h开始逐渐进食。患儿术后进行6个月的延续性随访,观察组患儿切口恢复美观,已经无法观察到切口瘢痕,两组患儿的生长发育均显示正常状态。观察组患儿手术时间(21.23±1.65)min及术后住院时间(5.58±1.98)d均显著短于对照组的(38.44±1.23)min、(9.67±1.22)d,差异具有统计学意义(P<0.05)。结论先天性肥厚性幽门狭窄患儿采用腹腔镜经脐单一部位幽门环肌切开术治疗,手术效果良好,手术创伤小而且安全。  相似文献   
6.
目的:通过对颈椎病患者上下终板弧形高度、椎间隙高度与椎间隙后骨赘的影像学测量,研究其相关性及其临床应用价值。方法:收集2017年9月至2018年9月颈椎病手术108例患者的临床资料,男48例,年龄30~72岁,平均52岁,女60例,年龄37~79岁,平均54岁。其中C2,3 6例,C3,4 15例,C4,5 32例,C5,6 42例,C6,7 13例。术前及术后摄颈椎X线片,利用PACS(Picture Archiving and Communication Systems)调阅影像,测量椎间隙的下上终板弧形高度(L1,L2),椎间隙高度(L3)及后方骨赘的宽度(L4)。利用Spearman分析它们之间的相关性。结果:L1与L4对比(r=-0.34,P<0.05),L3与L4对比(r=-0.36,P<0.05),存在负相关。L1与L3对比(r=0.38,P<0.05),L2与L3对比(r=0.48,P<0.05),存在正相关。L1与L2对比(P>0.05),L2与L4对比(P>0.05),差异无统计学意义。结论:下终板弧形高度与椎间隙后缘骨赘宽度呈负相关,通过其测量可明确颈椎退变程度,对颈椎病的早期防治有指导意义。  相似文献   
7.
8.
目的 评价中老年人社会资本量表的信效度,探索其在不同健康状况的中老年人群间的区分度。方法 针对已编制的中老年人社会资本量表,采用多阶段分层随机抽样方法,在四川省成都市及泸州市共抽取1 367名50岁及以上中老年居民进行问卷调查。运用Cronbach’s α系数、Pearson相关系数、t检验、探索性因子分析等方法评价量表的信度和效度。结果 1 367名中老年调查对象的社会资本量表总Cronbach’s α系数为0.67,各维度条目与总分的相关系数在0.30~0.79之间,具有良好的信度;探索性因子分析表明,14个条目提取出5个特征根大于1的因子,累积方差贡献率为68.84%;现患慢性疾病的中老年病例组人群的个人社会资本得分、家庭社会资本得分、社团社会资本得分、社区社会资本得分及社会资本总得分均低于未患病的对照人群组,宏观社会资本得分高于对照人群组,且差异均有统计学意义 (均 P<0.01),提示该量表具有较好的区分度。结论 中老年人社会资本量表具有较好的信度和效度,且对不同健康状况的50岁及以上中老年人中有较好的区分度。  相似文献   
9.
高血压病是我国发病率较高的疾病之一,西医治疗以长期服用降压药物为主要治疗方式,但常因依从性差的原因导致血压控制不佳,而用中医辨证治疗对于首次发现高血压的患者,可明显有效地降低高血压的发病率。高血压病在中医学中属"眩晕",在临床中常常会用半夏白术天麻汤来治疗眩晕,本文通过跟师医案及临床收集介绍半夏白术天麻汤治疗高血压眩晕临证方药的运用。  相似文献   
10.
目的 分析社区"5+1"糖尿病分阶段达标管理对2型糖尿病患者生存质量的干预效果及其影响因素,为提高患者生存质量提供依据。方法 采用分层整群抽样的方法在山西省、江苏省和宁夏回族自治区选择12个社区卫生服务中心,分别作为干预组(管理方式:社区"5+1"糖尿病分阶段达标管理)、对照组[管理方式:依据《国家基本公共卫生服务规范(2011年版)》的相关要求],进行为期2年的随访观察。采用面对面问卷调查的方式,收集患者的人口学信息等基本信息;采用健康调查简表(SF-36)对患者在干预前后测量生存质量。采用SAS 9.4软件进行双重差分法以及多重线性回归模型分析。结果 基线时共纳入2 467名研究对象,终末时共1 924人接受了为期2年完整的随访管理。干预后,干预组、对照组患者生理健康维度(PCS)、心理健康维度(MCS)评分变化净差值分别为13.6分、29.8分。多重线性回归分析结果显示,影响患者PCS得分的主要因素有年龄、医保类型、基线PCS得分以及所在地区,影响患者MCS得分的主要因素有年龄、医保类型、基线MCS得分、是否合并高血压以及所在地区。结论 社区"5+1"糖尿病分阶段达标管理对2型糖尿病患者生存质量的干预效果较好。  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