全文获取类型
收费全文 | 342737篇 |
免费 | 32505篇 |
国内免费 | 23644篇 |
专业分类
耳鼻咽喉 | 2900篇 |
儿科学 | 3951篇 |
妇产科学 | 4261篇 |
基础医学 | 37390篇 |
口腔科学 | 6075篇 |
临床医学 | 47919篇 |
内科学 | 47002篇 |
皮肤病学 | 3685篇 |
神经病学 | 16453篇 |
特种医学 | 12423篇 |
外国民族医学 | 171篇 |
外科学 | 31123篇 |
综合类 | 63480篇 |
现状与发展 | 90篇 |
一般理论 | 26篇 |
预防医学 | 25247篇 |
眼科学 | 9898篇 |
药学 | 36983篇 |
403篇 | |
中国医学 | 22830篇 |
肿瘤学 | 26576篇 |
出版年
2024年 | 1208篇 |
2023年 | 5369篇 |
2022年 | 13761篇 |
2021年 | 17393篇 |
2020年 | 13391篇 |
2019年 | 10965篇 |
2018年 | 11549篇 |
2017年 | 11183篇 |
2016年 | 9966篇 |
2015年 | 15873篇 |
2014年 | 19438篇 |
2013年 | 18083篇 |
2012年 | 26935篇 |
2011年 | 29506篇 |
2010年 | 19747篇 |
2009年 | 15873篇 |
2008年 | 19430篇 |
2007年 | 19110篇 |
2006年 | 18279篇 |
2005年 | 17436篇 |
2004年 | 11162篇 |
2003年 | 10440篇 |
2002年 | 8671篇 |
2001年 | 7432篇 |
2000年 | 7361篇 |
1999年 | 7190篇 |
1998年 | 4403篇 |
1997年 | 4363篇 |
1996年 | 3454篇 |
1995年 | 3164篇 |
1994年 | 2665篇 |
1993年 | 1683篇 |
1992年 | 2183篇 |
1991年 | 1863篇 |
1990年 | 1527篇 |
1989年 | 1281篇 |
1988年 | 1193篇 |
1987年 | 1046篇 |
1986年 | 830篇 |
1985年 | 608篇 |
1984年 | 377篇 |
1983年 | 277篇 |
1982年 | 163篇 |
1981年 | 155篇 |
1980年 | 116篇 |
1979年 | 153篇 |
1977年 | 54篇 |
1975年 | 61篇 |
1974年 | 59篇 |
1973年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Calculus bovis is commonly used for the treatment of stroke in traditional Chinese medicine. Hyodeoxycholic acid(HDCA) is a bioactive compound extracted from calculus bovis. When combined with cholic acid, baicalin and jas-minoidin, HDCA prevents hypoxia-reoxygenation-induced brain injury by suppressing endoplasmic reticulum stress-mediated apoptotic signaling. However, the effects of HDCA in ischemic stroke injury have not yet been studied. Neurovascular unit(NVU) dysfunction occurs in ischemic stroke. Therefore, in this study, we investigated the effects of HDCA on the NVU under ischemic conditions in vitro. We co-cultured primary brain microvascular endothelial cells, neurons and astrocytes using a transwell chamber co-culture system. The NVU was pre-treated with 10.16 or 2.54 μg/mL HDCA for 24 hours before exposure to oxygen-glucose deprivation for 1 hour. The cell counting kit-8 assay was used to detect cell activity. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling were used to assess apoptosis. Enzyme-linked immunosorbent assay was used to measure the expression levels of inflammatory cytokines, including interleukin-1β, interleukin-6 and tumor necrosis factor-α, and neurotrophic factors, including brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor. Oxidative stress-related factors, such as superoxide dismutase, nitric oxide, malondialdehyde and γ-glutamyltransferase, were measured using kits. Pretreatment with HDCA significantly decreased blood-brain barrier permeability and neuronal apoptosis, significantly increased transendothelial electrical resistance and γ-glutamyltransferase activity, attenuated oxidative stress damage and the release of inflammatory cytokines, and increased brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor expression. Our findings suggest that HDCA maintains NVU morphological integrity and function by modulating inflammation, oxidation stress, apoptosis, and the expression of neurotrophic factors. Therefore, HDCA may have therapeutic potential in the clinical management of ischemic stroke. This study was approved by the Ethics Committee of Experimental Animals of Beijing University of Chinese Medicine(approval No. BUCM-3-2016040201-2003) in April 2016. 相似文献
22.
目的 分析重庆市肺癌发病死亡和疾病负担归因于被动吸烟的情况,为开展肺癌防治提供建议。 方法 肺癌死亡个案数据来源于2019年重庆市肿瘤登记报告系统,被动吸烟率来自2013年重庆市慢性病及危险因素监测。计算人群归因危险度百分比(population attributable risk percent, PAR%)、被动吸烟导致的肺癌发病、死亡和疾病负担。采用Excel 2010与SPSS 25.0进行统计分析,率的比较采用χ2检验。 结果 2013年30岁及以上成年人被动吸烟率为52.37%。2019年重庆市30岁及以上人群肺癌发病率与标化发病率分别为118.44/10万与80.83/10万,死亡率与标化死亡率分别为96.51/10万、63.58/10万。肺癌发病率和死亡率归因于被动吸烟的PAR%分别为19.76和19.04,归因发病率与归因标化发病率分别为23.41/10万和16.34/10万,归因死亡率与归因标化死亡率分别为18.38/10万和12.40/10万。2019年重庆市30岁及以上肺癌早死所致寿命损失年率(years of life lost,YLL)、残疾所致寿命损失年率(years lived with disability,YLD)、调整伤残寿命损失年率(disability adjusted life year,DALY)分别为21.16‰、0.31‰、21.47‰,YLL率、YLD率、DALY率归因于被动吸烟的PAR%分别为21.16、19.76和20.49,归因YLL率为4.34‰,归因YLD率为0.06‰,归因DALY率为4.40‰。 结论 2019年重庆市30岁及以上人群肺癌发病率、死亡率、YLL率、DALY率高,被动吸烟率高,肺癌归因于被动吸烟的疾病负担重,应加强落实控烟工作。 相似文献
23.
Micro‐evolution of the hepatitis B virus genome in hepatitis B e‐antigen‐positive carriers: Comparison of genotypes B and C at various immune stages 下载免费PDF全文
24.
25.
26.
Parallel enzyme‐linked immunosorbent assay screening for human immunodeficiency virus among blood donors in five Chinese blood centres: a retrospective analysis 下载免费PDF全文
27.
Kui Li Jiawen Wang Shengxiong Liu Sen Su Chenjian Feng Xiaoxiang Fan Zhiyong Yin 《中华创伤杂志(英文版)》2015,18(2):65-73
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.
Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.
Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.
Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism. 相似文献
28.
29.
目的探讨8周基础军训(basic military training,BMT)对入伍新兵血像中红细胞及其相关指标的影响,为指导科学的军事训练提供参考。方法数据来自新疆边防部队2015年度入伍的50名男性新兵,分别在BMT前后测定并记录受试新兵的红细胞计数、血红蛋白浓度及血清铁蛋白等。结果经过8周的BMT,新兵血液中血红蛋白浓度、红细胞计数及血清铁蛋白均显著下降(P0.05,P0.01)。结论 8周BMT可能导致入伍新兵发生运动性贫血,铁缺乏可能是其主要原因。 相似文献
30.
目的 解析真实世界中乳腺恶性肿瘤患者的人群特征、诊断特征、中西医用药特征,为乳腺癌的临床防治提供参考。方法 采集2002年2月至2015年5月全国60家三级甲等医 院信息系统(Hospital Information System,HIS)中,出院诊断为“乳腺癌”的患者用药信息,采用SAS9.3统计软件,对人口学信息、诊断信息、医嘱用药信息等进行描述性分析。结果 39798例乳腺癌患者,平均年龄(50.93者,平均年龄)岁;多以门诊入院,入院病情以“一般”为主;合并疾病主要为高血压,骨肿瘤,联用西药以抑制肿瘤细胞增殖、治疗并发症、缓解放化疗不良反应为主;中医辨证以痰瘀互结证,气阴两虚证,肝气淤滞证,脾气亏虚证型最为常见,临床清热解毒剂、益气扶正剂,活血化瘀剂应用较多。结论 乳腺癌中西医结合治疗,联用药物广泛,临床治疗基本符合临床指南。 相似文献