全文获取类型
收费全文 | 27842篇 |
免费 | 2813篇 |
国内免费 | 1790篇 |
专业分类
耳鼻咽喉 | 322篇 |
儿科学 | 375篇 |
妇产科学 | 217篇 |
基础医学 | 1712篇 |
口腔科学 | 287篇 |
临床医学 | 3195篇 |
内科学 | 2240篇 |
皮肤病学 | 253篇 |
神经病学 | 633篇 |
特种医学 | 1114篇 |
外科学 | 2312篇 |
综合类 | 8086篇 |
现状与发展 | 2篇 |
预防医学 | 3328篇 |
眼科学 | 301篇 |
药学 | 3483篇 |
47篇 | |
中国医学 | 3270篇 |
肿瘤学 | 1268篇 |
出版年
2024年 | 166篇 |
2023年 | 435篇 |
2022年 | 900篇 |
2021年 | 1205篇 |
2020年 | 1017篇 |
2019年 | 554篇 |
2018年 | 553篇 |
2017年 | 782篇 |
2016年 | 597篇 |
2015年 | 1117篇 |
2014年 | 1500篇 |
2013年 | 1909篇 |
2012年 | 2587篇 |
2011年 | 2807篇 |
2010年 | 2564篇 |
2009年 | 2239篇 |
2008年 | 2320篇 |
2007年 | 2143篇 |
2006年 | 1882篇 |
2005年 | 1431篇 |
2004年 | 985篇 |
2003年 | 812篇 |
2002年 | 612篇 |
2001年 | 571篇 |
2000年 | 429篇 |
1999年 | 158篇 |
1998年 | 30篇 |
1997年 | 30篇 |
1996年 | 27篇 |
1995年 | 18篇 |
1994年 | 20篇 |
1993年 | 12篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
目的 调查神经内科门诊患者焦虑障碍与睡眠障碍之间的关系,并探讨应对方式在二者之间的潜在中介作用。方法 以2019年1—12月该院就诊的102例神经内科门诊患者为研究对象。分别采用综合医院用焦虑量表、匹兹堡睡眠指数问卷和应对方式问卷评估患者的焦虑障碍、睡眠障碍与应对方式。结果 焦虑障碍与睡眠障碍呈正相关(r=0.592,P=0.003)。多元线性回归分析显示,成熟应对方式如问题解决(β=—0.493,P=0.002)与混合应对方式如合理化(β=—0.336,P=0.021)对睡眠障碍与焦虑障碍的关系具有负向预测作用,而不成熟应对方式如幻想(β=0.237,P=0.041)、退避(β=0.223,P=0.040)对睡眠障碍与焦虑障碍的关系具有正向预测作用。结论 有效应对方式能够缓解焦虑障碍对睡眠障碍的负面影响。 相似文献
82.
双极电凝镊在扁桃体摘除术中的应用 总被引:2,自引:0,他引:2
目的:通过比较采用双极电凝镊与传统的剥离法实施扁桃体摘除的手术效果,探讨双极电凝镊在扁桃体摘除术中的应用效果。方法:选取行扁桃体手术摘除的患者100例,前瞻性地分为两组,比较手术时间、术中出血量及术后患者并发症、疼痛程度及恢复时间。结果:用双极电凝镊行扁桃体摘除与普通法扁桃体摘除相比,手术时间短,术中出血少,术后并发症发生率低,患者痛苦轻。结论:采用双极电凝镊扁桃体摘除手术效果明显优于普通剥离法扁桃体摘除,两方法术后恢复时间无统计学差别。 相似文献
83.
84.
Fu-Yu JING Xiu-Ling WANG Jia-Li SONG Yan GAO Jian-Lan CUI Wei XU Yang YANG Li-Juan SONG Hai-Bo ZHANG Jia-Peng LU Xi LI Xin ZHENG 《老年心脏病学杂志》2022,19(6):418
BACKGROUNDEpidemiologic studies have explored the association between a single cardiovascular risk factor (CVRF) and resting heart rate (RHR), but the research on the relation of multiple risk factors with RHR remains scarce. This study aimed to explore the associations between CVRFs clustering and the risk of elevated RHR.METHODSIn this cross-sectional study, adults aged 35–75 years from 31 provinces were recruited by the China PEACE Million Persons Projects from September 2015 to August 2020. We focused on seven risk factors: hypertension, diabetes mellitus, dyslipidemia, obesity, smoking, alcohol use, and low physical activity. Multivariate logistic regression was used to calculate odds ratios (OR) for elevated RHR (> 80 beats/min).RESULTSAmong 1,045,405 participants, the mean age was 55.67 ± 9.86 years, and 60.4% of participants were women. The OR (95% CI) for elevated RHR for the groups with 1, 2, 3, 4 and ≥ 5 risk factor were 1.11 (1.08–1.13), 1.36 (1.33–1.39), 1.68 (1.64–1.72), 2.01 (1.96–2.07) and 2.58 (2.50–2.67), respectively (Ptrend < 0.001). The association between the CVRFs clustering number and elevated RHR was much more pronounced in young males than in other age-sex subgroups. Clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR than those comprising more behavioral risk factors. CONCLUSIONSThere was a significant positive association between the CVRFs clustering number and the risk of elevated RHR, particularly in young males. Compared clusters comprising more behavioral risk factors, clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR. RHR may serve as an indicator of the cumulative effect of multiple risk factors.Over the past several years, the rapid development of smart wrist-worn devices has resulted in a convenient approach to monitoring resting heart rate (RHR) in daily life. RHR is becoming a promising indicator of cardiovascular health. Observational studies have shown that elevated RHR is associated with increased all-cause and cardiovascular mortality in populations with or without cardiovascular disease (CVD).[1,2] Elevated RHR has also been found to be associated with cardiovascular risk factors (CVRFs), such as hypertension, diabetes mellitus, dyslipidemia, low physical activity and smoking, indicating its potential to reflect total cardiac risk.[3–7] There is abundant epidemiologic evidence supporting the association between a single CVRF and RHR, but studies exploring associations between multiple CVRFs and RHR are limited. CVRFs tend to cluster within individuals, and several weak risk factors combined may result in a much higher risk than that due to a single strong risk factor. According to a cross-sectional survey in China, more than 45% of Chinese adults have two or more coexisting CVRFs.[8] Thus, it is important to consider the situation of multiple CVRFs clustering. However, very few studies have analyzed the association between CVRFs clustering and RHR, and several aspects remain unknown. Firstly, prior studies mainly focused on the relation between metabolic risk factors and RHR.[9–11] Behavioral risk factors such as smoking, physical activity and alcohol use have rarely been considered, even though these risk factors also have a significant effect on heart rate.[3,5,7] Secondly, most studies merely dealt with the relation of CVRFs clustering number with RHR, while regarding each number of risk factors, different combinations of risk factors have not yet been considered before.[9,12] It is important to consider different CVRF clustering patterns since some risk factors combined may lead to a higher risk of elevated RHR than others, even if the number of CVRFs is the same. Thirdly, prior studies did not assess associations stratified by sex and age. It has been well documented that RHR levels differ by sex and age. The RHR in women was on average 2–7 beats/min higher than that in men, and there was a decrease in the RHR with age.[13,14] As such, whether the associations of CVRFs clustering with RHR varied between sex and age remains unclear. Taking advantage of the large sample size in our study, we are able to include a wider range of CVRFs (metabolic and behavioral risk factors), comprehensively evaluate the association between these CVRFs clustering and RHR, and further explore sex and age differences. This finding may inform us whether RHR can be used as a simple and efficient metric for the identification of high-risk individuals who require more intensive risk factor evaluation and earlier cardiovascular health monitoring in resource-constrained countries with substantial CVD burdens, such as China. To bridge this knowledge gap, we used data from the China PEACE Million Persons Projects, a nationwide screening project, to explore (1) the association between the number of CVRFs clustering and elevated RHR in the overall population and populations stratified by age and sex; and (2) the associations between different CVRFs clusters and the risk of elevated RHR in the overall population and populations stratified by sex. 相似文献
85.
目的 研究旋转细胞培养系统(RCCS)模拟微重力环境对小鼠成纤维细胞株L929 lncRNA表达的影响.方法 体外培养L929细胞,随机分为模拟微重力组(SMG组)和正常重力组(NG组),每组3个样本.SMG组回转器轴心与地面平行旋转,NG组回转器轴心与地面垂直旋转,两组转速一致.RCCS培养7d,收集样本,提取样本总RNA,进行荧光标记和芯片杂交.利用Agilent Mouse lncRNA芯片分别检测SMG组和NG组L929细胞的lncRNA和mRNA表达,筛选差异表达显著的lncRNA,RT-qPCR验证芯片结果;利用GO和Pathway分析差异表达lncRNA的功能分布,结合mRNA差异表达谱,进行lncRNA-mRNA联合分析.结果 lncRNA芯片检测分析发现,RCCS模拟微重力环境下小鼠成纤维细胞L929共有238条差异表达的lncRNA,其中134条表达上调,104条表达下调;差异表达的mRNA共有237条,其中53条表达上调,184条表达下调.获取差异表达lncRNA的聚类分析图,对差异表达显著的4条lncRNA芯片结果进行RT-qPCR验证,结果相吻合.GO分析结果显示差异表达的lncRNA与巨噬细胞分化、伤口愈合的负性调节等生物学过程相关,Pathway分析结果显示差异表达的lncRNA与系统性红斑狼疮、TGF-β等信号通路相关.同时成功构建了lncRNA-mR-NA-TF可视化网络图.结论 RCCS模拟微重力环境显著影响L929细胞的lncRNA及mRNA表达谱,基于芯片技术的ln-cRNA靶基因预测和功能富集分析可为失重应激损伤机制探讨和修复措施建立提供理论依据. 相似文献
86.
目的通过对左心室射血分数(LVEF)、左心室舒张末容积(EDV)、左心室收缩末容积(ESV)、瞬时加速度波强(W1)、6 min步行距离(6MWD)的比较,探索W1评价冠心病患者左心功能的价值。方法应用ProSoundα10彩色多普勒超声诊断仪检测患者EDV、ESV、LVEF、W1,随即测量患者6MWD,之后2 h内行冠状动脉造影,选择冠状动脉造影证实至少1支血管一处狭窄>50%患者83例作为研究对象。将入选者按6MWD分为2组(6 min运动距离正常组,6MWD>350 m;6 min运动距离减退组,6MWD<350 m),比较两组间EDV、ESV、LVEF、W1。结果两组EDV、ESV、W1、LVEF比较均有统计学意义(P<0.01);W1、LVEF与6MWD呈明显正相关(P<0.01);EDV、ESV与6MWD呈明显负相关(P<0.01)。结论 W1有望成为一项反映左心室收缩功能的超声指标。 相似文献
87.
目的:探讨自制简易新装置对小鼠断尾取血的采血效果,建立简易、安全、方便、省时的小鼠采血方法。方法:用废弃的50 ml离心管、纸盒、纱布等制作2个采血装置,并列固定于同一6孔板上,对50只6~8周龄的昆明系小鼠进行重复4次断尾采血。结果:自制的固定装置价格低廉、制作简单、操作灵活,并可同时为2只小鼠采血,采血量可达0.25~0.50 ml,实验中小鼠无伤残、无死亡。结论:自制的小鼠固定装置采血量高、安全性好,是理想的小鼠断尾采血装置。 相似文献
88.
融合基因GM-CSF-BZLF1重组腺病毒表达载体的构建 总被引:1,自引:0,他引:1
目的构建粒细胞-巨噬细胞集落刺激因子(GM-CSF)和EB病毒即刻早期基因(BZLF1)融合基因的重组腺病毒表达载体。方法采用逆转录-聚合酶链反应分别获得GM-CSF和BZLF1编码序列的cDNA,应用剪接式重叠延伸(SOE)技术将两段基因通过多肽接头(Gly4Ser)3的DNA序列进行连接,构建融合基因GM-CSF-BZLF1。将融合基因GM-CSF-BZLF1定向亚克隆至pAdTrack-CMV质粒,在原核细胞E.coliBJ5183中完成穿梭质粒与骨架质粒pAdEasy-1的同源重组,构建融合基因GM-CSF-BZLF1真核表达载体pAd-GM-CSF-BZLF1。将真核表达载体pAd-GM-CSF-BZLF1转染293细胞,获得复制缺陷型重组腺病毒vAd-GM-CSF-BZLF1。RT-PCR鉴定感染重组腺病毒的293细胞中GM-CSF-BZLF1基因的表达。结果 GM-CSF-BZLF1基因插入重组腺病毒表达载体的预期位置,且插入序列完全正确;感染重组腺病毒vAd-GM-CSF-BZLF1的293细胞中检测到融合基因GM-CSF-BZLF1的转录表达。结论成功地构建了融合基因GM-CSF-BZLF1重组腺病毒表达载体,为进一步探讨GM-CSF-BZLF1的功能提供了理论基础和实验依据。 相似文献
89.
[背景]探讨子宫全切术的简易方法.[病例报告]行子宫全切术患者178例中行简易子宫全切术者为102例,传统式子宫全切术者为76例;简易子宫全切术与传统术式相比,手术时间及住院天数缩短,术中出血量及术后并发症无差别.[讨论]简易子宫全切术具有方法简单,手术时间短,病人恢复快及住院时间短等特点. 相似文献
90.
目的 探讨血浆mSEPT9对食管癌诊断的应用价值及其与放疗敏感性的关系。方法 选取2019年1月~2020年12月在蚌埠医学院第一附属医院放疗科接受根治性放疗的72例食管癌患者,运用PCR法分别检测患者放疗前及放疗后血浆mSEPT9,另以体检中心20例健康人作为对照。用受试者工作特征曲线(ROC曲线)评价mSEPT9对食管癌的诊断价值。用χ2检验分析mSEPT9与食管癌患者临床病理特征的关系。根据放疗疗效将食管癌患者分为放疗敏感组和不敏感组,比较放疗前两组患者mSEPT9差异。动态观察食管癌患者放疗前后mSEPT9变化,分别评价不同放疗敏感性组放疗前后mSEPT9差异。结果 mSEPT9诊断食管癌的灵敏度为62.5%,特异度为100%,ROC曲线下面积为0.813。mSEPT9与食管癌患者淋巴结转移、临床分期有关(P<0.05),与性别、年龄、侵犯部位、肿瘤长度、分化程度、浸润程度等无关(P>0.05)。放疗敏感组mSEPT9阳性率低于放疗不敏感组(53.06% vs 82.61%,P=0.016)。72例患者放疗后mSEPT9阳性率较放疗前显著下降(30.56% vs 62.5%,P<0.001),其中放疗敏感组放疗后mSEPT9阳性率较放疗前显著下降(14.29% vs 53.06%,P<0.001),不敏感组放疗后mSEPT9阳性率较放疗前无显著性差异(65.22% vs 82.61%,P=0.125)。结论 检测血浆mSEPT9有助于食管癌患者诊断和放疗敏感性预测。 相似文献