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   76941篇
  免费   7774篇
  国内免费   4943篇
耳鼻咽喉   988篇
儿科学   1057篇
妇产科学   1242篇
基础医学   8241篇
口腔科学   1207篇
临床医学   9494篇
内科学   11610篇
皮肤病学   1141篇
神经病学   3738篇
特种医学   2633篇
外国民族医学   28篇
外科学   7684篇
综合类   13633篇
现状与发展   17篇
一般理论   11篇
预防医学   5544篇
眼科学   1855篇
药学   8205篇
  76篇
中国医学   5126篇
肿瘤学   6128篇
  2024年   209篇
  2023年   1105篇
  2022年   2606篇
  2021年   3902篇
  2020年   3039篇
  2019年   2613篇
  2018年   2726篇
  2017年   2496篇
  2016年   2290篇
  2015年   3520篇
  2014年   4453篇
  2013年   4324篇
  2012年   5940篇
  2011年   6482篇
  2010年   4544篇
  2009年   3647篇
  2008年   4516篇
  2007年   4265篇
  2006年   4050篇
  2005年   3731篇
  2004年   2821篇
  2003年   2715篇
  2002年   2319篇
  2001年   1890篇
  2000年   1614篇
  1999年   1412篇
  1998年   828篇
  1997年   857篇
  1996年   615篇
  1995年   581篇
  1994年   497篇
  1993年   348篇
  1992年   460篇
  1991年   398篇
  1990年   309篇
  1989年   263篇
  1988年   259篇
  1987年   210篇
  1986年   162篇
  1985年   151篇
  1984年   95篇
  1983年   52篇
  1982年   31篇
  1981年   40篇
  1980年   24篇
  1979年   34篇
  1978年   24篇
  1977年   19篇
  1975年   18篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
Lessons Learned
  • SCB01A is a novel microtubule inhibitor with vascular disrupting activity.
  • This first‐in‐human study demonstrated SCB01A safety, pharmacokinetics, and preliminary antitumor activity.
  • SCB01A is safe and well tolerated in patients with advanced solid malignancies with manageable neurotoxicity.
BackgroundSCB01A, a novel microtubule inhibitor, has vascular disrupting activity.MethodsIn this phase I dose‐escalation and extension study, patients with advanced solid tumors were administered intravenous SCB01A infusions for 3 hours once every 21 days. Rapid titration and a 3 + 3 design escalated the dose from 2 mg/m2 to the maximum tolerated dose (MTD) based on dose‐limiting toxicity (DLT). SCB01A‐induced cellular neurotoxicity was evaluated in dorsal root ganglion cells. The primary endpoint was MTD. Safety, pharmacokinetics (PK), and tumor response were secondary endpoints.ResultsTreatment‐related adverse events included anemia, nausea, vomiting, fatigue, fever, and peripheral sensorimotor neuropathy. DLTs included grade 4 elevated creatine phosphokinase (CPK) in the 4 mg/m2 cohort; grade 3 gastric hemorrhage in the 6.5 mg/m2 cohort; grade 2 thromboembolic event in the 24 mg/m2 cohort; and grade 3 peripheral sensorimotor neuropathy, grade 3 elevated aspartate aminotransferase, and grade 3 hypertension in the 32 mg/m2 cohort. The MTD was 24 mg/m2, and average half‐life was ~2.5 hours. The area under the curve‐dose response relationship was linear. Nineteen subjects were stable after two cycles. The longest treatment lasted 24 cycles. SCB01A‐induced neurotoxicity was reversible in vitro.ConclusionThe MTD of SCB01A was 24 mg/m2 every 21 days; it is safe and tolerable in patients with solid tumors.  相似文献   
3.
健康状态的辨识是把握健康的前提。当前学界已存在专家辨识模式、标准辨识模式、数字辨识模式、智能辨识模式以及微观辨识模式等。联合多种辨识方法,构建健康状态辨识体系,形成常态与动态结合、主观与客观结合、人机互参的中医健康状态个体化辨识方法是研究的趋势所在。文章对未来的研究方向进行展望,探讨了多元辨识模式、远程辨识模式、终身辨识模式、自动辨识模式的思路方法,以期促进全民健康事业,助力"健康中国"战略。  相似文献   
4.
Direct peroral cholangioscopy (POC) using an ultra‐slim upper endoscope is one modality of POC for intraductal endoscopic evaluation and treatment of the bile duct. Choledochoduodenostomy (CDS) is one modality of biliary bypass surgery that provides a new route to the bile duct. We carried out direct POC using an ultra‐slim upper endoscope without the use of accessories in 10 patients (four sump syndromes, three bile duct strictures and three intrahepatic duct stones) previously undergoing surgical CDS. Direct POC was successful in all patients. The use of an intraductal balloon catheter was required in one patient for advancement of the endoscope into the bile duct. Distal bile ducts with sump syndromes were cleared using baskets and water irrigation under direct POC. Cholangiocarcinoma was diagnosed in one patient with hilar bile duct stricture after cholangioscopic evaluation and a targeting forceps biopsy under direct POC. Intrahepatic duct stones were successfully extracted after intraductal fragmentation under direct POC. Oozing bleeding occurred during intraductal lithotripsy but stopped spontaneously. Direct POC using an ultra‐slim upper endoscope without the assistance of accessories can easily be carried out in patients undergoing CDS.  相似文献   
5.
6.
BackgroundDual antiplatelet therapy (DAPT) is the cornerstone treatment of acute myocardial infarction (AMI).ObjectiveThe present study aimed to investigate the efficacy and safety of triple antiplatelet therapy (TAPT) in elderly female patients with diabetes and ST segment elevation myocardial infarction (STEMI), who had undergone percutaneous coronary intervention (PCI).MethodsWe designed a randomized, single-blind study. Control group A (97 elderly male patients with diabetes and STEMI, whose CRUSADE scores were < 30) received aspirin, ticagrelor, and tirofiban. A total of 162 elderly female patients with diabetes and STEMI were randomly divided into two groups according to CRUSADE score. Group B (69 patients with CRUSADE score > 31) received aspirin and ticagrelor. Group C (93 patients with CRUSADE score < 30) received aspirin, ticagrelor and tirofiban. P values < 0.05 were considered statistically significant.ResultsCompared to the findings in group A, post-PCI Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow and TIMI myocardial perfusion grade 3 were significantly less prevalent in group B (p < 0.05). When compared to groups A and C, the incidence of major adverse complications was significantly higher in group B (p < 0.05).ConclusionTAPT could effectively reduce the incidence of major complications in elderly female patients with diabetes and STEMI. However, close attention should be paid to hemorrhage in patients receiving TAPT. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)  相似文献   
7.
目的以基因表达数据集资料为研究对象,分析BCAN基因在肾透明细胞癌中的表达情况以及对患者预后的影响。方法在Oncomine数据库中挖掘BCAN在肾透明细胞癌(ccRCC)中的表达情况。从TCGA数据库中获取ccRCC患者临床资料和目的基因的表达信息并进行统计分析。利用GEO数据库中GSE73731数据集的ccRCC样本进行基因富集分析。利用String数据库分析与BCAN相关的蛋白。结果BCAN低表达组的ccRCC患者在病理分期及T分期方面低于高表达组(P<0.001;P=0.001);N分期及M分期差异无统计学意义(P>0.05)。BCAN低表达组患者的总生存期优于高表达组(P=0.033)。BCAN基因高表达组的样本主要富集在KRAS信号通路。结论BCAN可以通过多种途径来促进肿瘤细胞的侵袭能力,有望成为ccRCC不良预后的重要生物标志物之一。  相似文献   
8.
皮肤损伤后的异常愈合会导致病理性瘢痕的产生。病理性瘢痕的出现不仅影响美观,严重时还会造成心理和生理功能障碍。病理性瘢痕的机制研究对于瘢痕治疗有极为重要的意义。其中,动物瘢痕模型是目前研究病理性瘢痕的重要模型手段之一。理想的动物瘢痕模型应该在组织学、细胞学等层面尽可能接近于人类的病理性瘢痕。该文分别从传统技术动物瘢痕中的啮齿类动物模型、兔耳模型和猪模型,以及新技术动物瘢痕模型这两个方面,结合近年来在瘢痕领域应用较多的研究,进行了相应系统的阐述。  相似文献   
9.
In this article, a model-free off-policy reinforcement learning algorithm is applied to address the optimal tracking problem based on multiplayer non-zero-sum games for discrete-time linear systems. In contrast to the traditional method and the policy iteration method for solving the optimal tracking problems, the proposed algorithm operates with the system data rather than the knowledge of the system dynamics. For performing the proposed algorithm, an auxiliary augmented system is constructed via assembling the original system and the reference trajectory while a discount factor is introduced into the performance indexes. It is analyzed that the solutions of the proposed algorithm converge to the Nash equilibrium and the result is not influenced by the probing noise. Two simulations are presented to verify the feasibility and effectiveness of the proposed algorithm.  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