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   81987篇
  免费   8015篇
  国内免费   5112篇
耳鼻咽喉   1002篇
儿科学   1121篇
妇产科学   1204篇
基础医学   8624篇
口腔科学   1396篇
临床医学   9322篇
内科学   12043篇
皮肤病学   1328篇
神经病学   4111篇
特种医学   3088篇
外国民族医学   31篇
外科学   8864篇
综合类   14599篇
现状与发展   16篇
一般理论   7篇
预防医学   5981篇
眼科学   1690篇
药学   8733篇
  69篇
中国医学   5289篇
肿瘤学   6596篇
  2024年   145篇
  2023年   931篇
  2022年   1585篇
  2021年   3316篇
  2020年   2654篇
  2019年   2422篇
  2018年   2639篇
  2017年   2552篇
  2016年   2383篇
  2015年   3512篇
  2014年   4399篇
  2013年   4645篇
  2012年   6489篇
  2011年   7106篇
  2010年   5149篇
  2009年   4308篇
  2008年   5201篇
  2007年   4974篇
  2006年   4794篇
  2005年   4320篇
  2004年   3486篇
  2003年   3408篇
  2002年   2982篇
  2001年   2211篇
  2000年   1790篇
  1999年   1382篇
  1998年   851篇
  1997年   777篇
  1996年   614篇
  1995年   557篇
  1994年   498篇
  1993年   336篇
  1992年   425篇
  1991年   408篇
  1990年   296篇
  1989年   235篇
  1988年   249篇
  1987年   188篇
  1986年   163篇
  1985年   153篇
  1984年   109篇
  1983年   55篇
  1982年   32篇
  1981年   39篇
  1980年   32篇
  1979年   37篇
  1978年   29篇
  1977年   25篇
  1976年   29篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
目的收集特重度烧伤(总TBSA50%以上或三度TBSA20%以上或伴有严重并发症者)患者围术期凝血指标(APTT、PT、FIB、DD和PLT),分析静吸复合麻醉对患者凝血功能的影响及其临床意义。 方法选取近3年内蒙古医科大学第三附属医院烧伤外科收治的特重度烧伤患者148例,根据入院14 d内的预后分为死亡组和生存组,生存组男性129例,女性9例;年龄24~59岁,平均(43.30±12.90)岁。死亡组男性8例,女性2例;年龄26~63岁,平均(46.19±15.41)岁。收集入院时(T0),术前(早晨入手术室前,T1),术毕(送至PACU未拔除气管导管前,T2)及术后2 d(T3)4个时间点的凝血指标,比较两组凝血指标动态差异。 结果死亡组休克期输液量、累计血浆、红细胞输入量显著高于生存组(P<0.01)。T0时,生存组的FIB(1.78±0.32)显著高于死亡组(1.26±0.07)(P<0.05);T2时,两组APTT、PT均显著缩短(P<0.05),生存组的FIB(3.86±0.40)显著高于死亡组(2.45±1.02)(P<0.05);T3时,死亡组PLT显著低于生存组(P<0.01)。 结论特重度烧伤患者在围手术期易出现高凝状态,并且这可能导致患者死亡。静吸复合麻醉和围术期大量液体复苏会促进患者的高凝状态。  相似文献   
2.
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   
3.
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   
4.
正临床资料患者,男,52岁。云南省文山州丘北县人。因躯干、四肢结节、斑块5个月余,伴疼痛性结节10余天就诊。患者2019年2月因"接触油漆"后于双上肢出现结节、斑块,逐渐蔓延至双下肢、躯干,伴瘙痒,当地县中医医院考虑"过敏性皮炎",予抗过敏治疗(具体药物不详)后,结节、斑块未完全消退,偶有痒感,自用草药外洗治疗(具体药物不详),病情无好转,10天前患者四肢及躯干相继出现大小不等的结节,自觉疼痛。  相似文献   
5.
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.  相似文献   
6.
7.
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   
8.
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