全文获取类型
收费全文 | 80681篇 |
免费 | 7479篇 |
国内免费 | 5312篇 |
学科分类
医药卫生 | 93472篇 |
出版年
2024年 | 330篇 |
2023年 | 1295篇 |
2022年 | 3199篇 |
2021年 | 4062篇 |
2020年 | 3082篇 |
2019年 | 2624篇 |
2018年 | 2809篇 |
2017年 | 2516篇 |
2016年 | 2364篇 |
2015年 | 3599篇 |
2014年 | 4365篇 |
2013年 | 4104篇 |
2012年 | 6190篇 |
2011年 | 6518篇 |
2010年 | 4188篇 |
2009年 | 3298篇 |
2008年 | 4461篇 |
2007年 | 4273篇 |
2006年 | 3886篇 |
2005年 | 3832篇 |
2004年 | 2755篇 |
2003年 | 2499篇 |
2002年 | 2236篇 |
2001年 | 1823篇 |
2000年 | 1905篇 |
1999年 | 1997篇 |
1998年 | 1274篇 |
1997年 | 1256篇 |
1996年 | 979篇 |
1995年 | 952篇 |
1994年 | 777篇 |
1993年 | 485篇 |
1992年 | 561篇 |
1991年 | 511篇 |
1990年 | 437篇 |
1989年 | 386篇 |
1988年 | 302篇 |
1987年 | 306篇 |
1986年 | 235篇 |
1985年 | 186篇 |
1984年 | 123篇 |
1983年 | 84篇 |
1982年 | 62篇 |
1981年 | 47篇 |
1980年 | 33篇 |
1979年 | 44篇 |
1978年 | 18篇 |
1974年 | 17篇 |
1973年 | 17篇 |
1966年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献4.
5.
目的:探究原发性肝癌患者手术切除术后早期复发影响因素分析。方法:对广州市番禺区中医院2017年2月-2019年2月收治的原发性肝癌患者98例进行回顾性分析,依据各项临床指标分析手术切除术后早期复发的影响因素。结果:原发性肝癌患者经由手术切除后出现复发的可能性较高,同时手术切缘有残留、包膜不完整、肿瘤结节、心理因素、甲胎蛋白、血管侵犯、肝硬化及肿瘤直径等均是影响原发性肝癌手术期后再复发的高危因素。结论:原发性肝癌通常具有术后复发的生物学特性,依据对手术切除术之后早期复发因素的分析,对手术风险与治疗方案进行充分评估,同时要求患者进行定期复查及随访等工作,可对患者手术成功以及并发症的防治等均具有积极意义。 相似文献
6.
7.
Melatonin induces apoptosis of colorectal cancer cells through HDAC4 nuclear import mediated by CaMKII inactivation 下载免费PDF全文
Melatonin induces apoptosis in many different cancer cell lines, including colorectal cancer. However, the precise mechanisms involved remain largely unresolved. In this study, we provide evidence to reveal a new mechanism by which melatonin induces apoptosis of colorectal cancer LoVo cells. Melatonin at pharmacological concentrations significantly suppressed cell proliferation and induced apoptosis in a dose‐dependent manner. The observed apoptosis was accompanied by the melatonin‐induced dephosphorylation and nuclear import of histone deacetylase 4 (HDAC4). Pretreatment with a HDAC4‐specific siRNA effectively attenuated the melatonin‐induced apoptosis, indicating that nuclear localization of HDAC4 is required for melatonin‐induced apoptosis. Moreover, constitutively active Ca2+/calmodulin‐dependent protein kinase II alpha (CaMKIIα) abrogated the melatonin‐induced HDAC4 nuclear import and apoptosis of LoVo cells. Furthermore, melatonin decreased H3 acetylation on bcl‐2 promoter, leading to a reduction of bcl‐2 expression, whereas constitutively active CaMKIIα(T286D) or HDAC4‐specific siRNA abrogated the effect of melatonin. In conclusion, the present study provides evidence that melatonin‐induced apoptosis in colorectal cancer LoVo cells largely depends on the nuclear import of HDAC4 and subsequent H3 deacetylation via the inactivation of CaMKIIα. 相似文献
8.
9.
10.