全文获取类型
| 收费全文 | 346444篇 |
| 免费 | 22159篇 |
| 国内免费 | 7572篇 |
专业分类
| 耳鼻咽喉 | 4149篇 |
| 儿科学 | 9854篇 |
| 妇产科学 | 6630篇 |
| 基础医学 | 28874篇 |
| 口腔科学 | 8050篇 |
| 临床医学 | 37486篇 |
| 内科学 | 43495篇 |
| 皮肤病学 | 4591篇 |
| 神经病学 | 20733篇 |
| 特种医学 | 7901篇 |
| 外国民族医学 | 31篇 |
| 外科学 | 36865篇 |
| 综合类 | 50948篇 |
| 现状与发展 | 12篇 |
| 一般理论 | 29篇 |
| 预防医学 | 35707篇 |
| 眼科学 | 5483篇 |
| 药学 | 30664篇 |
| 380篇 | |
| 中国医学 | 30665篇 |
| 肿瘤学 | 13628篇 |
出版年
| 2023年 | 5518篇 |
| 2022年 | 9775篇 |
| 2021年 | 13392篇 |
| 2020年 | 12422篇 |
| 2019年 | 18494篇 |
| 2018年 | 16202篇 |
| 2017年 | 12897篇 |
| 2016年 | 10332篇 |
| 2015年 | 9661篇 |
| 2014年 | 19911篇 |
| 2013年 | 21484篇 |
| 2012年 | 18260篇 |
| 2011年 | 19838篇 |
| 2010年 | 15938篇 |
| 2009年 | 14663篇 |
| 2008年 | 14292篇 |
| 2007年 | 14734篇 |
| 2006年 | 12902篇 |
| 2005年 | 11178篇 |
| 2004年 | 9126篇 |
| 2003年 | 8003篇 |
| 2002年 | 6291篇 |
| 2001年 | 5657篇 |
| 2000年 | 4715篇 |
| 1999年 | 4085篇 |
| 1998年 | 3312篇 |
| 1997年 | 3145篇 |
| 1996年 | 2756篇 |
| 1995年 | 2664篇 |
| 1994年 | 2551篇 |
| 1993年 | 2054篇 |
| 1992年 | 2068篇 |
| 1991年 | 1792篇 |
| 1990年 | 1585篇 |
| 1989年 | 1417篇 |
| 1988年 | 1359篇 |
| 1987年 | 1155篇 |
| 1985年 | 3945篇 |
| 1984年 | 4970篇 |
| 1983年 | 3494篇 |
| 1982年 | 3965篇 |
| 1981年 | 3679篇 |
| 1980年 | 3294篇 |
| 1979年 | 3023篇 |
| 1978年 | 2615篇 |
| 1977年 | 1969篇 |
| 1976年 | 2217篇 |
| 1975年 | 1705篇 |
| 1974年 | 1489篇 |
| 1973年 | 1329篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
71.
目的:研究全麻复合硬膜外在高龄患者腹腔镜直肠癌根治术中的应用效果。方法:选择60岁以上择期行腹腔镜直肠癌根治术患者60例,随机分为G组和GA组,每组各30例。G组患者为单纯全麻组,GA组患者为硬膜外复合全麻组。GA组患者在诱导前取L1~2硬膜外穿刺置管,予0.5%罗哌卡因5 ml,术中每小时追加5~7 ml。两组患者诱导方法相同:即,咪哒唑仑0.04 mg/kg、舒芬太尼0.3~0.4μg/kg、顺阿曲库铵0.15~0.20 mg/kg、依托咪酯0.2~0.3 mg/kg。监测并记录患者血压(BP),心率(HR),心电图(ECG),术中全麻药用量及术后患者苏醒情况。结果:GA组患者气腹后、拔管前BP、HR明显低于G组(P<0.05),且全麻药用量明显低于G组(P<0.05)。结论:全麻复合硬膜外应用于老年腹腔镜直肠癌手术较单纯全麻用药量减少,术中循环更加稳定,是腹腔镜直肠癌根治术比较安全可行的麻醉方法。 相似文献
72.
Ngai-Yin Chan Chi-Chung Choy Ho-Chuen Yuen Hoi-Fan Chow Ho-Fai Fong 《The Canadian journal of cardiology》2019,35(4):396-404
Background
Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study.Methods
A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD.Results
Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events.Conclusions
Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting. 相似文献73.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.
Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.
Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).
Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity. 相似文献
74.
Accuracy and Precision of Acetabular Component Placement With Imageless Navigation in Obese Patients
Leonard T. Buller Alexander S. McLawhorn Jose A. Romero Peter K. Sculco David J. Mayman 《The Journal of arthroplasty》2019,34(4):693-699
Background
Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.Methods
A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.Results
The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).Conclusion
Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.Level of Evidence
Therapeutic Level IV. 相似文献75.
76.
目的 研究凉血通瘀方对高血压大鼠急性脑出血模型脑组织miRNA表达的影响，对差异表达的miRNA靶基因进行分析，探索凉血通瘀方可能的药效机制。方法 将自发性高血压大鼠随机分成对照组（B）和实验组（C）。适应性饲养一周后，C组灌胃凉血通瘀方，B组灌胃等体积生理盐水，连续5天，每天1次。构建脑出血模型后收集脑组织，借助全转录组测序技术获得miRNA表达量，与miRBase数据库比对获取已知miRNA，使用miRDeep2预测新miRNA。差异分析软件为DESeq2，筛选阈值为|log2FC| ≥1 并且P <0.05。对显著差异表达的miRNA进行靶基因预测，对靶基因进行GO功能、KEGG通路富集和PPI网络分析。结果 实验组和对照组对比，共发现21个显著差异表达的miRNA，上调有9个，下调有12个，共预测得到1243个有统计学意义的靶基因。GO富集分析发现，生物过程中突触囊泡分泌的调节、神经递质分泌的调节和神经递质运输的调节占前三位，神经元投射终点、全膜、质膜区域和细胞投射则是主要的细胞成分。分子功能分别为小GTPase绑定、底物特异性跨膜转运蛋白活性和离子跨膜转运体活性。通路分析结果显示，靶基因在癌证通路、pI3K-Akt信号通路、人类乳头瘤病毒感染、神经活性配体-受体相互作用和MAPK通路等分布广泛。采用STRING网站和Cytoscape软件，根据MCC算法筛选出ADRA2C、CASR、CCL28、CCR1、DRD2、GNAT3、GRM2、DYNC1LI1、GABBR1、GNAI1等核心靶基因。结论 凉血通瘀方对脑出血急性期鼠脑组织内miRNA的表达有重要影响；显著差异表达miRNAs可能通过靶向核心基因调控凉血通瘀方干预急性脑出血的病理过程及预后。 相似文献
77.
78.
79.
80.