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   256546篇
  免费   20313篇
  国内免费   6753篇
耳鼻咽喉   1789篇
儿科学   3505篇
妇产科学   3698篇
基础医学   26970篇
口腔科学   3841篇
临床医学   19902篇
内科学   32940篇
皮肤病学   3364篇
神经病学   15195篇
特种医学   7744篇
外国民族医学   8篇
外科学   18479篇
综合类   33967篇
现状与发展   27篇
一般理论   11篇
预防医学   21122篇
眼科学   2950篇
药学   55215篇
  88篇
中国医学   15781篇
肿瘤学   17016篇
  2024年   464篇
  2023年   3438篇
  2022年   5953篇
  2021年   10455篇
  2020年   8928篇
  2019年   8753篇
  2018年   8887篇
  2017年   9768篇
  2016年   9708篇
  2015年   9240篇
  2014年   12403篇
  2013年   19088篇
  2012年   14046篇
  2011年   16046篇
  2010年   10933篇
  2009年   10666篇
  2008年   11946篇
  2007年   12880篇
  2006年   12048篇
  2005年   11050篇
  2004年   9474篇
  2003年   8482篇
  2002年   6630篇
  2001年   6094篇
  2000年   5045篇
  1999年   4281篇
  1998年   3464篇
  1997年   3517篇
  1996年   3140篇
  1995年   2849篇
  1994年   2610篇
  1993年   2179篇
  1992年   2110篇
  1991年   1942篇
  1990年   1664篇
  1989年   1346篇
  1988年   1330篇
  1987年   1211篇
  1986年   1079篇
  1985年   1475篇
  1984年   1181篇
  1983年   884篇
  1982年   892篇
  1981年   728篇
  1980年   692篇
  1979年   560篇
  1978年   385篇
  1977年   320篇
  1976年   293篇
  1975年   240篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
背景 致密性骨炎(OCI)和其他疾病有时难以鉴别,探讨血清骨转换生化标志物可为OCI的鉴别诊断提供依据。 目的 探索女性OCI患者的血清骨转换生化标志物的水平变化及临床意义。 方法 回顾性选取2013年6月至2022年2月在北京积水潭医院门诊及住院诊断为OCI的61例女性患者作为观察组,年龄15~50岁,平均(33.8±6.6)岁,病程2周~15年。选择同期61例女性体检健康者作为对照组,年龄15~48岁,平均(35.6±7.6)岁。比较两组一般临床资料和血清骨转换生化标志物水平,并对血清骨转换生化标志物与病情相关指标进行相关性分析。 结果 观察组血清白蛋白(45.4±2.9)g/L低于对照组(46.5±2.8)g/L(t=2.190,P<0.05)。血清骨转换生化标志物比较结果显示,观察组血清1型胶原羧基末端肽β特殊序列(β-CTX)〔0.28(0.23,0.37)μg/L〕、N-端骨钙素(OC)〔13.1(11.2,16.2)μg/L〕、25-羟维生素D3〔25-(OH)VD3〕〔(14.1±5.1)μg/L〕低于对照组〔0.36(0.29,0.48)μg/L,15.6(13.7,17.3)μg/L,(17.5±6.6)μg/L〕(Z=-2.983、-3.255,t=3.081,P<0.05)。长病程亚组OC水平〔14.6(12.4,18.5)μg/L〕高于短病程亚组〔11.7(10.2,14.0)μg/L〕(Z=-2.407,P<0.05)。多孕亚组β-CTX〔0.25(0.22,0.32)μg/L〕、OC水平〔12.2(10.3,15.0)μg/L〕低于非多孕亚组〔0.33(0.26,0.44)μg/L、13.4(12.0,18.8)μg/L〕(Z=-2.486、-1.897,P<0.05)。相关性分析显示,观察组血清1型前胶原氨基端延长肽(tP1NP)与妊娠次数、生产次数均呈负相关(rs=-0.276、-0.298,P<0.05),OC与体质指数(BMI)、视觉模拟评分法(VAS)评分、妊娠次数均呈负相关(rs=-0.284、-0.374、-0.360,P<0.05),25-(OH)VD3水平与BMI呈正相关(rs=0.275,P<0.05)。 结论 女性OCI患者血清OC、β-CTX水平明显降低,可为鉴别其他疾病提供依据;血清OC水平可以反映OCI患者的严重程度,同时OC水平与患者妊娠次数相关;tP1NP与妊娠次数、生产次数相关。  相似文献   
3.
《Cancer cell》2022,40(8):835-849.e8
  1. Download : Download high-res image (220KB)
  2. Download : Download full-size image
  相似文献   
4.
BackgroundHamstring strain injuries are the most common type of injury in elite football and are associated with a high risk of reinjury, particularly those involving the intramuscular tendon (IMT). Limited information is available regarding the rehabilitation and return to sport (RTS) processes following such injuries. This case study describes the clinical presentation of an elite football player following IMT hamstring injury, their on- and off-pitch rehabilitation alongside performance monitoring throughout RTS and beyond.Case scenarioAn elite football player suffered a grade 2c hamstring injury during an English Premier League (EPL) match. The player underwent early post-injury management, alongside progressive off-pitch physical preparation. The ‘control-chaos continuum’ was used as a framework for on-pitch rehabilitation to prepare the player for a return to full team training and competition. Objective and subjective markers of the player's response to progressive on- and off-pitch loading were monitored throughout RTS and beyond.OutcomesThe player returned to on-pitch rehabilitation after 11 days, to full team training having achieved weekly pre-injury chronic running load outputs after 35 days and played in the EPL 40 days post-injury. The player did not suffer reinjury for the rest of the EPL season.ConclusionAn understanding the unique structural and mechanical properties of the IMT, alongside expected RTS timeframes are important to inform rehabilitation and decision-making processes post-injury. Performance and frequent load-response monitoring throughout RTS and beyond, in conjunction with practitioner experience and effective communication are critical in facilitating effective RTS and reduce risk of reinjury following IMT injury.  相似文献   
5.
Background and objective: Myocardial infarction (MI) is a common critical disease of the cardiovascular system. The process of MI is often accompanied by the excessive activation of cardiac sympathetic nerves, which leads to arrhythmia. Resiniferatoxin (RTX) is a transient receptor potential vanilloid 1 (TRPV1), involved in the cardiac sympathetic afferent reflex. However, whether RTX can reduce the occurrence of arrhythmia and exert a cardioprotective effect by inhibiting the sympathetic reflex during MI is still unknown. Methods: The left anterior descending artery of cardiac was clamped to construct a model of MI. RTX (50 μg/ml) was used by epicardial application in MI rats. Ventricular electrophysiologic properties were continuously monitored by a body surface ECG. Yrosine hydroxylase (TH) and growth associated protein 43 (GAP43) were detected by Immunofluorescence staining. Connexin43 and transforming growth factor beta receptor 1 (TGF-β1) were detected by western blot. Norepinephrine (NE) and BNP levels in blood and tissue were determined by ELISA. Cardiac function was assessed by echocardiography. Results: The ERP, APD90, QRS, QT and the Tend-Tpeak intervals in MI rats were all prolonged, but decreased after RTX treatment (n = 3, P<0.05). In contrast, the RR interval was shortened in the MI group, but prolonged in the MI+RTX group (n = 3, P<0.05). RTX treatment significantly reduced ventricular arrhythmias after MI. TH- and GAP43-positive nerve densities and TGF-β1, and cx-43 protein expression were up-regulated in the MI group compared to the sham group, and they were decreased in the MI+RTX group compared to the MI group (n = 3, P<0.05). RTX can decrease serum and tissue NE and BNP levels (n = 3, P<0.05). RTX pretreatment significantly decreased heart rate, HW/BW ratio and LVIDS, and increased LVEF andLVFS values (n = 3, P<0.05). Conclusion: RTX improved cardiac dysfunction, ventricular electrophysiologic properties, and sympathetic nerve remodeling in rats with MI by inhibiting the excessive cardiac sympathetic drive.  相似文献   
6.
7.
8.
9.
目的 运用CT区分脾脏血管性病变与淋巴瘤。方法 回顾性分析20例经手术、穿刺病理学检查证实的脾脏病变的发病年龄、性别、脾脏指数、病变大小、数目、有无液化、钙化、强化幅度、强化方式等特征,并进行统计学分析。结果 20例脾脏病变中,11例血管性病变(6例海绵状血管瘤,3例窦岸细胞血管瘤,2例硬化性血管瘤样结节性转化),9例淋巴瘤;两组间发病年龄、病变大小、数目、有无液化、钙化等差异无统计学意义;两组间脾脏指数、动脉期强化幅度差异具有统计学意义(P<0.05)。5例海绵状血管瘤呈不均匀性强化,1例呈渐进性填充式强化,2例窦岸细胞血管瘤呈“雀斑征”,1例硬化性血管瘤样结节性转化呈“辐轮征”;9例淋巴瘤实质部分均呈均匀、轻中度强化。结论 脾脏血管性病变与淋巴瘤CT表现不同,CT有助于明确诊断。  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