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   173490篇
  免费   16764篇
  国内免费   10743篇
耳鼻咽喉   1281篇
儿科学   2107篇
妇产科学   1847篇
基础医学   24645篇
口腔科学   2968篇
临床医学   21246篇
内科学   23871篇
皮肤病学   1830篇
神经病学   8358篇
特种医学   6282篇
外国民族医学   81篇
外科学   16760篇
综合类   29427篇
现状与发展   42篇
一般理论   16篇
预防医学   12401篇
眼科学   4177篇
药学   19926篇
  166篇
中国医学   10000篇
肿瘤学   13566篇
  2024年   705篇
  2023年   2739篇
  2022年   7104篇
  2021年   8945篇
  2020年   6611篇
  2019年   5793篇
  2018年   6011篇
  2017年   5555篇
  2016年   5271篇
  2015年   7627篇
  2014年   9570篇
  2013年   9239篇
  2012年   13059篇
  2011年   13806篇
  2010年   9645篇
  2009年   7790篇
  2008年   9333篇
  2007年   9313篇
  2006年   8583篇
  2005年   7755篇
  2004年   5888篇
  2003年   5791篇
  2002年   4951篇
  2001年   4113篇
  2000年   3596篇
  1999年   3211篇
  1998年   2020篇
  1997年   2149篇
  1996年   1488篇
  1995年   1433篇
  1994年   1298篇
  1993年   912篇
  1992年   1103篇
  1991年   1023篇
  1990年   872篇
  1989年   795篇
  1988年   727篇
  1987年   623篇
  1986年   563篇
  1985年   448篇
  1984年   390篇
  1983年   313篇
  1982年   272篇
  1981年   238篇
  1980年   199篇
  1979年   205篇
  1978年   195篇
  1977年   211篇
  1976年   191篇
  1974年   157篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
目的 探讨剂量组学在预测肺癌根治性放疗患者放射性肺炎发生中的应用潜能。方法 回顾性收集行根治性放疗的314例肺癌患者的临床资料、放疗剂量文件、定位及随访CT图像,根据临床资料及影像学随访资料对放射性肺炎进行分级,提取全肺的剂量组学特征,构建机器学习模型。应用1000次自助抽样法(bootstrap)的最小绝对值收敛和选择算子嵌套逻辑回归(LASSO‐LR)及1000次bootstrap的赤池信息量准则(AIC)向后法筛选与放射性肺炎相关的剂量组学特征,随机按照7∶3划分为训练集及验证集,应用逻辑回归建立预测模型,并应用ROC曲线及校正曲线评价模型的性能。结果 共提取120个剂量组学特征,经LASSO‐LR降维筛选得到12个特征进入“特征池”,再经过AIC向后法筛选,最终筛选出6个剂量组学特征进行模型构建,训练集AUC为0.77(95%CI为0.65~0.87),独立验证集AUC为0.72(95%CI为0.64~0.81)。结论 利用剂量组学建立的预测模型具有预测放射性肺炎发生的潜力,但仍需继续纳入多中心数据及前瞻性数据进一步挖掘剂量组学的应用潜能。  相似文献   
12.
13.
14.
15.
1. To investigate Genkwa Flos hepatotoxicity, a cell metabolomics strategy combined with serum pharmacology was performed on human HL-7702 liver cells in this study.

2. Firstly, cell viability and biochemical indicators were determined and the cell morphology was observed to confirm the cell injury and develop a cell hepatotoxicity model. Then, with the help of cell metabolomics based on UPLC-MS, the Genkwa Flos group samples were completely separated from the blank group samples in the score plots and seven upregulated as well as two down-regulated putative biomarkers in the loading plot were identified and confirmed. Besides, two signal molecules and four enzymes involved in biosynthesis pathway of lysophosphatidylcholine and the sphingosine kinase/sphingosine-1-phosphate pathway were determined to investigate the relationship between Genkwa Flos hepatotoxicity and these two classic pathways. Finally, the metabolic pathways related to specific biomarkers and two classic metabolic pathways were analyzed to explain the possible mechanism of Genkwa Flos hepatotoxicity.

3. Based on the results, lipid peroxidation and oxidative stress, phospholipase A2/lysophosphatidylcholine pathway, the disturbance of sphingosine-1-phosphate metabolic profile centered on sphingosine kinase/sphingosine-1-phosphate pathway and fatty acid metabolism might be critical participators in the progression of liver injury induced by Genkwa Flos.  相似文献   

16.
17.
目的应用免疫组织化学染色的方法检测硒蛋白P在直肠癌组织中的表达,以探讨其与直肠癌发生的关系及临床意义。方法收集山西大医院2013年6月至2014年5月间行手术治疗并经病理证实的60例直肠癌组织、40例直肠腺瘤组织、40例正常直肠组织,应用SABC法检测上述组织中硒蛋白P的表达情况,结果依据阳性细胞百分率和染色强度进行评价,三组间样本率的比较采用无序行×列表?2检验(α=0.05),两组间样本率的比较采用独立样本?2检验(α=0.016 7),硒蛋白的表达与直肠癌临床病理参数的关系采用四格表?2检验(α=0.05)进行分析。结果硒蛋白P在正常直肠组织、直肠腺瘤组织、直肠癌组织中的表达阳性率分别为82.5%(33/40)、70.0%(28/40)、45.0%(27/60),组间差异有统计学意义(?2=15.680,P<0.001),癌组织与正常组织、腺瘤组织间差异显著(?2=14.063,P<0.001;?2=6.061,P=0.015);硒蛋白的表达与肿瘤大小、是否浸润浆膜有关(P<0.05),与性别、年龄、淋巴结有无转移、肿瘤细胞分化程度、TNM分期无关(P>0.05)。结论硒蛋白在直肠癌中低表达,对直肠癌的发生发展具有重要作用,有望为直肠癌的治疗提供新思路。  相似文献   
18.
Gluteal muscle contracture (GMC), presented with hip abduction and external rotation when crouching, is common in several ethnicities, particularly in Chinese. It remains unclear that the reasons why these children are weak and have no choice to accept repeated intramuscular injection. Here, we found some unique cases which may be useful to explain this question.We describe a series of special GMC patients, who are accompanied with congenital heart disease (CHD). These cases were first observed in preoperative examinations of a patient with atrial septal defect (ASD), which was proved by chest X-ray and cardiac ultrasound. From then on, we gradually identified additional 3 GMC patients with CHD. The original patient with ASD was sent to cardiosurgery department to repair atrial septal first and received arthroscopic surgery later. While the other 3 were cured postoperative of ventricular septal defect (VSD), tetralogy of fallot (TOF), patent ductus arteriosus (PDA), respectively, and had surgery directly.The study gives us 3 proposals: (1) as to CHD children, it is essential to decrease the use of intramuscular injection, (2) paying more attention to cardiac examination especially cardiac ultrasound in perioperative period, and (3) taking 3D-CT to reconstruct gluteal muscles for observing contracture bands clearly in preoperation. However, more larger series of patients are called for to confirm these findings.  相似文献   
19.
20.
In order to solve the problem of long-term (>9 months) efficacy in the treatment of Alzheimer''s disease (AD) by conventional therapy (CT), a staged and multiply-targeted sequential therapy based on the evolvement of patterns (STEP) was developed. Its main innovations include: (1) the time order of evolution of patterns defined by Chinese medicine (CM) in AD was found, that is, "the orderly pattern evolution starting from Shen (Kidney) deficiency, progressing to phlegm, stasis and fire, and worsening to severe toxin as well as functional collapse"; (2) the cascade hypothesis of Shen deficiency in AD and its sequential therapy based on Shen-reinforcing was proposed, that is, "reinforcing Shen in the early stage and throughout the whole process, resolving phlegm, activating blood and purging fire in the middle stage, detoxifying and replenishing vitality to stop the collapse in the advanced stage", and through meta-analysis, clinical drug use was optimized, thus the leap from "inferential selection" to "evidence-based selection" was realized; (3) the STEP regimen combined with CT maintained cognitive and behavioral stability in AD patients for at least 12 months, with cognitive enhancement and behavioral synergy after 9 months, and cognitive benefit was superior to CT at 9, 12, 15, 18, 21, and 24 months, respectively. The 2-year cognitive improvement rate was increased by 25.64% (P=0.020) and the cognitive deterioration rate was decreased by 48.71% (P=0.000). Among them, the cognitive and functional benefits of Shen-reinforcing therapy for very early AD (350 cases) for 1 year were better than the placebo (P<0.001), and the dementia conversion rate was reduced by 8.85% (P=0.002). The behavioral symptomatic relief of patients with vascular dementia received fire-purging therapy (540 cases) was superior to those received CT (P=0.016). These data suggested that the STEP regimen has synergistic effects on CTs at least in terms of cognitive benefit, and the earlier the use, the greater the benefit will have. Therefore, the STEP regimen should be considered as one of the clinical options, particularly for the dearth of effective pharmaceutical or immunological interventions that are currently available for AD.  相似文献   
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