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   1527篇
  免费   84篇
  国内免费   24篇
耳鼻咽喉   3篇
儿科学   89篇
妇产科学   9篇
基础医学   231篇
口腔科学   54篇
临床医学   82篇
内科学   310篇
皮肤病学   91篇
神经病学   95篇
特种医学   26篇
外科学   76篇
综合类   106篇
预防医学   116篇
眼科学   19篇
药学   175篇
中国医学   55篇
肿瘤学   98篇
  2024年   2篇
  2023年   30篇
  2022年   29篇
  2021年   52篇
  2020年   43篇
  2019年   116篇
  2018年   108篇
  2017年   51篇
  2016年   39篇
  2015年   57篇
  2014年   144篇
  2013年   109篇
  2012年   73篇
  2011年   103篇
  2010年   68篇
  2009年   76篇
  2008年   75篇
  2007年   83篇
  2006年   41篇
  2005年   46篇
  2004年   39篇
  2003年   17篇
  2002年   23篇
  2001年   29篇
  2000年   9篇
  1999年   10篇
  1998年   12篇
  1997年   8篇
  1996年   5篇
  1995年   7篇
  1994年   8篇
  1993年   5篇
  1992年   2篇
  1991年   4篇
  1990年   3篇
  1988年   2篇
  1986年   2篇
  1985年   8篇
  1984年   8篇
  1983年   14篇
  1982年   9篇
  1981年   15篇
  1980年   16篇
  1979年   11篇
  1978年   11篇
  1977年   3篇
  1975年   2篇
  1974年   3篇
  1973年   2篇
  1971年   1篇
排序方式: 共有1635条查询结果,搜索用时 995 毫秒
1.
《Indian heart journal》2022,74(6):474-477
Background and objectivesAmbulatory blood pressure (BP) monitoring has become useful in the diagnosis and management of hypertensive individuals. In this study we tried to know the role of office and ambulatory BP in treated hypertensive patients.Methods and patientsProspective cohort of 561 treated hypertensive patients were enrolled in the study. Hypertension definitions were according to JNC 8 classification. Office BP and ambulatory BP monitoring was done according to defined protocol.ResultsFrom a subgroup of 158 treated hypertensive patients, 91(16.2%) patients were having white coat hypertension (p value 0.00 by Pearson chi square test). In a subset of 403 patients who were having controlled BP on the day of enrolment as well as on the day of attaching ambulatory BP monitor; 98 (17.4%) patients were having masked uncontrolled hypertension (MUCH). In addition there was very significant percentage of non-dippers and reverse dippers. In our study we found that office BP has a moderate to low specificity and sensitivity and low negative predictive value for overall control in treated hypertensive patients.ConclusionAmbulatory BP monitoring should be included in the management protocol of treated hypertensive patients, for the optimal BP control.  相似文献   
2.
3.
目的 分析m6A阅读器胰岛素样生长因子2-mRNA结合蛋白1(insulin-like growth factor 2 mRNA-binding protein 1,IGF2BP1)在肝细胞癌(hepatocellular carcinoma,HCC)中的表达水平及其对HCC患者预后的影响,并探讨IGF2BP1在HCC发生发展中的作用及其潜在机制。方法 基于5对HCC癌及相应癌旁组织mRNA-seq数据和TCGA数据库LIHC的mRNA-seq数据综合分析IGF2BP1在HCC中的表达情况,同时利用TCGA数据库中343例HCC患者的临床随访资料分析IGF2BP1表达水平对HCC患者总生存期的影响。基于TCGA数据库筛选IGF2BP1的共表达mRNA,并利用m6Avar在线网站预测mRNA的m6A位点及其RNA结合蛋白等信息,最终构建IGF2BP1的基因调控网络。结果 IGF2BP1基因在HCC中表达上调(log2FC HCC转录组数据=10.684,P<0.001;log2FC TCGA-LIHC数据集=7.032,P<0.001)。生存分析显示IGF2BP1低表达的HCC患者中位生存时间为5.84年,IGF2BP1高表达患者为4.44年,高表达患者总生存期缩短(P=0.011)。22个差异表达的mRNA与IGF2BP1存在靶向结合关系,并与其表达水平呈正相关。其中,HMGA2等15个高表达mRNA的HCC患者总生存期缩短。HMGA2、PEG10、CEP55、RHO、CDC6和KIF23基因中的潜在m6A甲基化位点位于mRNA 3'UTR端的miRNA结合区域。结论 IGF2BP1在HCC中高表达且导致患者总生存期缩短。IGF2BP1可能通过m6A甲基化及miRNA抑制作用的方式上调mRNA的表达,促进HCC发生并导致不良预后。  相似文献   
4.
Among the numerous signaling pathways involved in tumorigenesis, PI3K‐AKT‐mTOR is a key one that regulates diverse cellular functions. However, its prognostic value in esophageal carcinoma remains unclear. In our study, we examined the immunohistochemical expression of phosphorylated (p‐) AKT, mTOR, p70S6K and 4E‐BP1 along with the mutational status of PIK3CA and AKT1 genes by High Resolution Melting Analysis and Pyrosequencing in 44 esophageal carcinomas. The results were correlated with the clinicopathological characteristics of the patients in an effort to define their possible prognostic significance. Total p‐mTOR cytoplasmic expression, assessed in 10 random areas, was positively correlated with tumor stage (Kruskal–Wallis ANOVA, I/II vs III/IV, p = 0.0500). Μoreover, maximum p‐mTOR cytoplasmic immunoexpression, estimated in hot spot areas, was positively associated with tumor grade (Mann–Whitney U test, I/II vs III, p = 0.0565). Interestingly, p‐4E‐BP1 immunoreactivity was negatively correlated with tumor histological grade (Mann–Whitney U test, I/II vs III, p = 0.0427). No mutation was observed in exons 9 and 20 of PIK3CA gene and in exon 4 of AKT1 gene. In conclusion, our findings depict the presence of activated PI3K/AKT/mTOR pathway in esophageal cancer bringing forward p‐mTOR and p‐4E‐BP1 for their potential role in esophageal carcinogenesis. Additional studies are warranted to validate our findings.  相似文献   
5.
原位杂交法检测BP1基因在乳腺癌组织中表达   总被引:3,自引:0,他引:3  
目的探讨BP1同源盒基因在乳腺癌中的表达及其与临床病理指标的关系。方法收集165例乳腺癌临床和病理资料,采用原位杂交法检测BP1的表达,同时用二步法进行ER、p53、PCNA、bcl2、cerbB2免疫组化染色。结果BP1基因表达率为67.88%,免疫组化:ER70.30%、p5349.09%、PCNA74.55%、bcl253.33%、cerbB275.52%。BP1与bcl2具有相关性(P<0.01),且均与ER相关(P<0.05),与p53呈负相关(P<0.05)。BP1与PCNA、cerbB2、患者年龄、组织学类型、淋巴结转移等无相关性。结论BP1可能通过某种非依赖p53基因调控机制,与bcl2、ER协同抑制肿瘤细胞的凋亡而参与乳腺癌的发生。  相似文献   
6.
Background: Mivazerol is a new and selective α2-adrenoceptor agonist, devoid of hypotensive effects, which has been designed to prevent adverse cardiac outcome in perioperative patients with, or at risk of coronary artery disease. Methods: In the present study, the effects of mivazerol on hemodynamic changes induced by trachea-exposure surgery stress were investigated in pentobarbital-anesthetized rats, and compared to those of dexmedetomidine. Results: Intravenous infusion of 3 different doses of mivazerol (3.75, 7.5 and 15 μg kg-1 h-1) did not significantly alter BP but caused a dose-related decrease in HR. The maximal decrease in HR was approximately 87 beats/min. Contrary to mivazerol, dexmedetomidine (7.5 μg kg-1 h-1, i.v.) decreased both BP (11±3.2 mmHg) and HR. The maximum decrease in HR was approximately 104 beats/min. Surgical stress produced a rapid increase in BP (maximal increase of 50 mmHg) and HR (maximal increase of 100 beats/min), which lasted for at least 15 min. Constant infusion of mivazerol, at a dose of 15 μg kg-1 h-1, beginning 20 min prior to surgery and lasting for 35 min, significantly inhibited surgical stress-induced increases in BP (P < 0.05) and HR (P < 0.001). Dexmedetomidine, at a dose which produced hypotension and profound bradycardia prior to surgery, did not have any effect on the surgical stress-induced elevation in BP (P>0.05), but prevented the increase in HR (P < 0.05). Pretreatment with the α2-adrenoceptor antagonist rau-wolscine (0.5 mg/kg, i.v.) blocked the bradycardia induced by mivazerol as well as the inhibitory effect of mivazerol on surgical stress-induced elevations in HR and BP. Conclusion: Mivazerol attenuates surgical stress-induced elevations in BP and HR during pentobarbital anesthesia in rats, and these effects are mediated by stimulation of α2-adrenoceptors. Unlike dexmedetomidine, mivazerol does not reduce BP, and is also more potent than dexmedetomidine in blunting surgical stress-induced increases in BP in pentobarbital-anesthetized rats.  相似文献   
7.
Abstract The study of animal lectins and glycoconjugates has become an important area of research in biomedical sciences, as these molecules are believed to play important roles in a variety of biological processes. This report describes a study of the expression of an animal lectin, IgE-binding protein (?BP), also known as Mac-2 and CBP35, in human skin. We have analyzed cultured human keratinocytes as well as normal human skin and a number of epidermal neoplasms, by immunoblotting. immuno-fluorescence and immunohistochemistry. We showed that ?BP is expressed in human keratinocytes, hair follicles, sebaceous and sweat glands. We found that cBP expression retains in various epidermal neoplasms, including basal cell carcinoma, squamous cell carcinoma and keratoacan-thoma, although the level of expression appears to be reduced as compared to normal epidermis. The immunohistochemical analysis also suggests that the level of ?BP expression appears to be dependent on the degree of cellular differentiation of keratinocytes.  相似文献   
8.
神经网络分析方法用于心脏病诊断的研究   总被引:2,自引:1,他引:1  
神经网络可以很好的拟合任意的非线性函数。我们从 QRS波群的高频三维频谱中提取出一些定量的特征参数 ,用神经网络的方法对这些参数进行有监督的学习训练 ,最终能在由这些特征参数张成的 m维空间中构建出一个 m维的曲面来区分病人和健康人的 QRS波群高频三维频谱 ,从而使得训练后的网络能基于 QRS波群的高频三维频谱自行诊断出病人和健康人  相似文献   
9.
用神经网络法预测药物在体透过人皮肤的渗透性   总被引:4,自引:2,他引:2  
目的:预测药物在体透过人皮肤的渗透性。方法:以正辛醇/水分配系数(logP)、分子体积(V)、氢键酸度(∑β2^H)和氢键碱度(∑β2^H)等理化参数作为输入层神经元,以药物在一定时间内在体透过人皮肤的透过比的对数值(R,透过量/未透过量)作为输出层神经元,建立起合适的BP(Back—propagation)神经网络。结果:17个药物在一定时间内在体透过人皮肤的透过比的神经网络计算值和实测值均相当符合。结论:用BP神经网络法可以较好地预测药物在体透过人皮肤的渗透性。  相似文献   
10.
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