首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   51275篇
  免费   5063篇
  国内免费   4046篇
耳鼻咽喉   485篇
儿科学   531篇
妇产科学   627篇
基础医学   6303篇
口腔科学   779篇
临床医学   7021篇
内科学   7489篇
皮肤病学   548篇
神经病学   2812篇
特种医学   1957篇
外国民族医学   29篇
外科学   4755篇
综合类   8621篇
现状与发展   12篇
一般理论   7篇
预防医学   3664篇
眼科学   1521篇
药学   5726篇
  48篇
中国医学   3255篇
肿瘤学   4194篇
  2024年   163篇
  2023年   842篇
  2022年   2145篇
  2021年   2720篇
  2020年   2132篇
  2019年   1759篇
  2018年   1827篇
  2017年   1827篇
  2016年   1691篇
  2015年   2423篇
  2014年   3085篇
  2013年   2748篇
  2012年   3911篇
  2011年   4355篇
  2010年   2700篇
  2009年   2196篇
  2008年   2783篇
  2007年   2709篇
  2006年   2597篇
  2005年   2597篇
  2004年   1742篇
  2003年   1660篇
  2002年   1387篇
  2001年   1150篇
  2000年   1095篇
  1999年   1121篇
  1998年   712篇
  1997年   680篇
  1996年   513篇
  1995年   517篇
  1994年   445篇
  1993年   291篇
  1992年   329篇
  1991年   275篇
  1990年   229篇
  1989年   216篇
  1988年   200篇
  1987年   169篇
  1986年   132篇
  1985年   86篇
  1984年   37篇
  1983年   50篇
  1982年   13篇
  1981年   22篇
  1980年   15篇
  1979年   20篇
  1977年   8篇
  1976年   7篇
  1974年   7篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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   
12.
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   
13.
Helicobacter pylori (H. pylori) is a main risk factor for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is involved in the development and progression of H. pylori-associated GC. However, the exact molecular mechanism of this process remains unclear. The AKT/GSK3β signaling pathway has been demonstrated to promote EMT in several types of cancer. The present study investigated whether H. pylori infection induced EMT, and promoted the development and metastasis of cancer in the normal gastric mucosa, and whether this process was dependent on AKT activation. The expression levels of the EMT-associated proteins, including E-cadherin and N-cadherin, were determined in 165 gastric mucosal samples of different disease stages by immunohistochemical analysis. The expression levels of E-cadherin, N-cadherin, AKT, phosphorylated (p-)AKT (Ser473), GSK3β and p-GSK3β (Ser9) were further determined in H. pylori-infected Mongolian gerbil gastric tissues and cells co-cultured with H. pylori by immunohistochemical analysis and western blotting. The results indicated that the expression levels of the epithelial marker E-cadherin were decreased, whereas the expression levels of the mesenchymal marker N-cadherin were increased during gastric carcinogenesis. Their expression levels were associated with H. pylori infection. Furthermore, H. pylori infection resulted in downregulation of E-cadherin expression and upregulation of N-cadherin expression in Mongolian gerbils and GES-1 cells. In addition, an investigation of the associated mechanism of action revealed that p-AKT (Ser473) and p-GSK3β (Ser9) were activated in GES-1 cells following co-culture with H. pylori. Furthermore, following pretreatment of the cells with the AKT inhibitor VIII, the expression levels of E-cadherin, N-cadherin, p-AKT and p-GSK3β did not show significant differences between GES-1 cells that were co-cultured with or without H. pylori. The levels of p-AKT and p-GSK3β were increased in H. pylori-infected Mongolian gerbils. In conclusion, the present study demonstrated that H. pylori infection activated AKT and resulted in the phosphorylation and inactivation of GSK3β, which in turn promoted early stage EMT. These effects were AKT-dependent. This mechanism may serve as a prerequisite for GC development.  相似文献   
14.
15.
Phytonutrients extracted from natural resources are receiving much attention among researchers due to their highly antioxidative characteristics which prevent several degenerative diseases including cardiovascular diseases and cancers. These nutraceutical compounds can be used in food, pharmaceutical and cosmetic products as natural antioxidants, preservatives, colourants and functional foods. Huge volume of food wastes are generated from the processing industry and these low-value food residues are rich in various phytonutrients worth recovering. This approach of valorisation reduces the generation of food wastes and is cost-effective considering the cheap feedstock, reduced waste management expenses and high market value of extracted compounds. In light of the health and safety risks posed by commonly used organic extraction solvents derived from the petrochemical industry, there is a need to recover the phytonutrients using green, sustainable and efficient solvents that are safe for human consumption. This work discusses ethyl lactate as a safe, green, efficient and potentially cheap solvent to recover phytonutrients from fruit and vegetable by-products. Ethyl lactate is compared with other organic solvents commonly used from the aspects of safety, environmental impacts and efficiency. Current challenges when employing ethyl lactate are also discussed.  相似文献   
16.
17.
18.
目的研制加强型鼻咽通气道应用于五官科鼻腔手术后的气道管理。方法选取2014年1月至2015年3月行五官科鼻腔手术的患者60例,将其分为A组和B组,各30例。A组作为加强型鼻咽通气道组,术毕在膨胀止血海绵中放置加强型鼻咽通气道保留鼻腔通气;B组作为对照组,术毕采用传统单纯填塞膨胀止血海绵。通过术后24、48 h随访,对两组患者进行疼痛、睡眠质量、口干程度评分,并对其进行对比分析。结果加强型鼻咽通气道具有良好的抗压抗折性;A组患者24、48 h睡眠质量、口干程度评分均明显优于B组,差异均有统计学意义(P<0.05)。结论加强型鼻咽通气道用于五官科鼻腔手术后气道管理可增强气道管理安全性及患者舒适度。  相似文献   
19.
目的 探讨综合医院发热门诊应对新型冠状病毒感染肺炎的应急管理方法及效果。 方法 加强发热门诊的管理,包括优化发热预检分诊工作流程、合理布局发热门诊、修订发热门诊工作职责与流程指引、合理调配人力资源、加强相关人员培训、严格落实院感防控措施、提供后勤保障、加强健康宣教与管理。 结果 接诊患者13 761例次,采集咽拭子591例次,静脉输液11 973例次,氧气吸入998例次。 结论 加强综合医院发热门诊管理,能有效提高护理人员对新型冠状病毒肺炎疫情的应对能力,保障护理安全。  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号