全文获取类型
收费全文 | 152118篇 |
免费 | 49070篇 |
国内免费 | 2922篇 |
专业分类
耳鼻咽喉 | 2355篇 |
儿科学 | 5612篇 |
妇产科学 | 2908篇 |
基础医学 | 24863篇 |
口腔科学 | 6290篇 |
临床医学 | 20660篇 |
内科学 | 36470篇 |
皮肤病学 | 8752篇 |
神经病学 | 17671篇 |
特种医学 | 5476篇 |
外国民族医学 | 11篇 |
外科学 | 23630篇 |
综合类 | 7712篇 |
现状与发展 | 12篇 |
一般理论 | 37篇 |
预防医学 | 9045篇 |
眼科学 | 2897篇 |
药学 | 12556篇 |
30篇 | |
中国医学 | 3654篇 |
肿瘤学 | 13469篇 |
出版年
2024年 | 135篇 |
2023年 | 745篇 |
2022年 | 1809篇 |
2021年 | 3979篇 |
2020年 | 6658篇 |
2019年 | 12364篇 |
2018年 | 12190篇 |
2017年 | 12949篇 |
2016年 | 13744篇 |
2015年 | 14490篇 |
2014年 | 15108篇 |
2013年 | 16205篇 |
2012年 | 10137篇 |
2011年 | 10027篇 |
2010年 | 12585篇 |
2009年 | 8667篇 |
2008年 | 6565篇 |
2007年 | 5469篇 |
2006年 | 5280篇 |
2005年 | 4675篇 |
2004年 | 4434篇 |
2003年 | 4423篇 |
2002年 | 4006篇 |
2001年 | 3269篇 |
2000年 | 2739篇 |
1999年 | 1888篇 |
1998年 | 728篇 |
1997年 | 643篇 |
1996年 | 542篇 |
1995年 | 463篇 |
1994年 | 450篇 |
1993年 | 293篇 |
1992年 | 781篇 |
1991年 | 645篇 |
1990年 | 577篇 |
1989年 | 533篇 |
1988年 | 449篇 |
1987年 | 464篇 |
1986年 | 385篇 |
1985年 | 310篇 |
1984年 | 252篇 |
1983年 | 207篇 |
1982年 | 126篇 |
1981年 | 133篇 |
1980年 | 110篇 |
1979年 | 228篇 |
1978年 | 171篇 |
1977年 | 114篇 |
1976年 | 117篇 |
1975年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
91.
92.
93.
94.
Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll‐like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts. Melanocyte exposure to LPS upregulated the expression of TLR4 mRNA and enhanced the DNA‐binding activity of NF‐κB p50 and p65. We found substantial differences in the LPS‐stimulated expression of numerous genes encoding inflammatory cytokines and chemokines between the cells with various melanin contents. In lightly pigmented melanocytes, the most significantly upregulated genes were nicotinamide phosphoribosyltransferase (NAMPT/visfatin), the chemokines CCL2 and CCL20, and IL6, while the genes for CXCL12, IL‐16 and the chemokine receptor CCR4 were the most significantly upregulated in heavily pigmented cells. Moreover, the lightly pigmented melanocytes secreted much more NAMPT, CCL2 and IL‐6. The results of our study suggest modulatory effect of melanogenesis on the immune properties of normal epidermal melanocytes. 相似文献
95.
目的 检测微小核糖核酸(microribonucleicacids,miRNA)在老年性黄斑变性(age-related macular degeneration,AMD)患者中的表达,并探讨miRNA的表达量与AMD病程之间的关系。方法 选取2014年1月至2016年11月于同济大学附属第十人民医院眼科门诊就诊的AMD患者6例为试验组,并选取同期6名正常人为对照组,通过基因芯片技术检测两组血液中miRNA的表达量。扩大样本的病例对照研究中共纳入126例AMD患者和140名正常人,检测其血液样本中miRNA的表达,比较两组人群间miRNA的表达量差异。结果 通过基因芯片技术,在试验组与对照组间共检测出216个miRNA存在表达差异(均为P<0.05),与对照组相比,试验组中111个miRNA表达量上升,105个miRNA表达量下降,差异均有统计学意义(均为P<0.05)。扩大样本的病例对照研究结果表明,在AMD患者中,miR-27a-3p、miR-29b-3p、miR-195-5p的表达量显著上升,同时,湿性AMD患者血液中miR-27a-3p的表达量高于干性AMD患者,差异均有统计学意义(均为P<0.05)。结论 AMD患者外周血中miRNA表达量水平有明显变化,miR-27a-3p、miR-29b-3p、miR-195-5p可能成为AMD血清学诊断和预后的标志物。 相似文献
96.
97.
目的采用Meta分析方法评价18F-脱氧葡萄糖正电子发射计算机体层摄影(18F-FDG PET/CT)和增强CT(CECT)诊断经导管肝动脉化疗栓塞术(TACE)术后存活或复发病灶的临床价值。方法根据PRISMA报告规范开展Meta分析。检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方和维普数据库中18F-FDG PET/CT和CECT诊断TACE术后存活或复发病灶的临床研究,时间至2019-04。由2位研究人员独立筛选文献、提取资料,根据诊断准确性研究质量评价工具-2(QUADAS-2)评价纳入研究的偏倚风险后,采用Stata 12.0软件进行Meta分析,计算其汇总敏感度(Sen)和特异度(Spe),绘制受试者工作特征曲线(SROC)并计算曲线下面积(AUC)。结果共纳入10篇18F-FDG PET/CT及13篇CECT诊断TACE术后存活或复发病灶的原始研究,分别包括322例患者的467个病灶和748例患者的943个病灶。Meta分析显示,18F-FDG PET/CT诊断TACE术后存活或复发病灶的Sen=0.92(95%CI为0.87~0.94)、Spe=0.95(95%CI为0.82~0.99)、AUC=0.97(95%CI为0.93~0.99);CECT诊断TACE术后存活或复发病灶的Sen=0.72(95%CI为0.66~0.78)、Spe=0.99(95%CI为0.93~1.00)、AUC=0.87(95%CI为0.83~0.89)。此外,CECT诊断TACE术后存活或复发Sen(Z=2.34,P=0.02)和AUC(Z=2.21,P=0.03)值低于18F-FDG PET/CT,差异有统计学意义。结论相比于CECT,18F-FDG PET/CT对TACE术后存活或复发病灶具有较高诊断效能,可视为TACE术后存活或复发病灶有效的影像学诊断方法。 相似文献
98.
Victoria A. Chang Dawn M. Meyer Brett C. Meyer 《Journal of stroke and cerebrovascular diseases》2019,28(1):163-166
Background
Acute stroke codes may be activated for anisocoria, but how often these codes lead to a final stroke diagnosis or alteplase treatment is unknown. The purpose of this study was to assess the frequency of anisocoria in stroke codes that ultimately resulted in alteplase administration.Methods
We retrospectively assessed consecutive alteplase-treated patients from a prospectively-collected stroke registry between February 2015 and July 2018. Based on the stroke code exam, patients were categorized as having isolated anisocoria [A+(only)], anisocoria with other findings [A+(other)], or no anisocoria [A?]. Baseline demographics, stroke severity, alteplase time metrics, and outcomes were also collected.Results
Ninety-six patients received alteplase during the study period. Of the 94 who met inclusion criteria, there were 0 cases of A+(only). There were 9 cases of A+(other) (9.6%). A+(other) exhibited higher baseline National Institutes of Health (NIH) Stroke Scale scores compared to A? (17 versus 7; P?=?.0003), and no additional differences in demographics or alteplase time metrics. Final stroke diagnosis and other outcome measures were no different between A+(other) and A?. Of the A+ patients without pre-existing anisocoria, 5 of 6 (83%) had posterior circulation events or diffuse subarachnoid hemorrhage.Conclusions
In this exploratory analysis, zero patients with isolated anisocoria received alteplase treatment. Anisocoria as a part of the neurologic presentation occurred in 10% of alteplase patients, and was strongly associated with a posterior circulation event. Therefore, we conclude that anisocoria has a higher likelihood of leading to alteplase treatment when identified in the presence of other neurologic deficits. 相似文献99.
100.