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   110396篇
  免费   7545篇
  国内免费   3233篇
耳鼻咽喉   925篇
儿科学   2825篇
妇产科学   1702篇
基础医学   10773篇
口腔科学   1641篇
临床医学   12912篇
内科学   15365篇
皮肤病学   1017篇
神经病学   6217篇
特种医学   5365篇
外国民族医学   53篇
外科学   12679篇
综合类   16643篇
现状与发展   19篇
一般理论   2篇
预防医学   5011篇
眼科学   993篇
药学   7738篇
  66篇
中国医学   2847篇
肿瘤学   16381篇
  2024年   178篇
  2023年   1529篇
  2022年   3596篇
  2021年   4646篇
  2020年   3819篇
  2019年   3554篇
  2018年   3560篇
  2017年   3452篇
  2016年   3694篇
  2015年   3974篇
  2014年   7272篇
  2013年   7223篇
  2012年   5977篇
  2011年   6805篇
  2010年   5473篇
  2009年   5587篇
  2008年   5582篇
  2007年   5663篇
  2006年   5154篇
  2005年   4327篇
  2004年   3726篇
  2003年   3089篇
  2002年   2748篇
  2001年   2411篇
  2000年   2085篇
  1999年   1900篇
  1998年   1554篇
  1997年   1503篇
  1996年   1385篇
  1995年   1204篇
  1994年   1058篇
  1993年   846篇
  1992年   724篇
  1991年   625篇
  1990年   517篇
  1989年   468篇
  1988年   511篇
  1987年   397篇
  1986年   309篇
  1985年   444篇
  1984年   446篇
  1983年   269篇
  1982年   339篇
  1981年   259篇
  1980年   243篇
  1979年   216篇
  1978年   157篇
  1977年   152篇
  1976年   145篇
  1975年   100篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.  相似文献   
2.
《Cancer cell》2022,40(3):318-334.e9
  1. Download : Download high-res image (268KB)
  2. Download : Download full-size image
  相似文献   
3.
《Vaccine》2022,40(23):3236-3243
BackgroundInfections can have a significant impact on morbidity and mortality in multiple sclerosis (MS) patients. Therefore, vaccinations are of immense importance. If vaccination willingness is to be increased, possible influencing factors should be identified. The aim of the present study was to investigate the status of active immunisation in MS patients in association with sociodemographic, clinical-neurological, psychopathological and personality variables using the NEO-Five Factor Inventory, the Temperament and Character Inventory-Revised and the Hospital Anxiety and Depression Scale.MethodFour hundred and four MS patients from two German neurological hospitals were examined for their vaccination attitudes, in detail, the general willingness to vaccinate and the current vaccination status of mumps, measles and rubella (MMR) as well as tetanus and influenza. We also looked at the current level of disability in relation to the current vaccination status, as well as possible associated personality and psychopathological variables.ResultsPatients with a complete MMR vaccination status were significantly younger and those with a complete influenza vaccination status were significantly older than those with related incomplete vaccination status. Tetanus vaccination status completeness did not differ depending on age and did not show substantial association with personality scores. However, influenza vaccination completeness was associated with differences in personality and psychopathological variables; extraversion, openness, novelty seeking, harm avoidance and anxiety. A reported general vaccination willingness was significantly correlated with the current completeness of tetanus and influenza vaccinations. Novelty seeking, persistence, extraversion, agreeableness, conscientiousness and neuroticism were found associated with an increased vaccination willingness. Anxiety and depression were not related to general vaccination willingness.ConclusionsNo specific personality trait could be defined on its own in relation to general vaccination willingness or complete vaccination status. Younger patients should be made more aware of influenza vaccination. Reasons for rather low vaccination rates need to be further investigated.  相似文献   
4.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
5.
目的 探讨右美托咪定联合综合体温保护对腔镜手术治疗老年恶性肿瘤患者苏醒期质量及免疫功能的影响。方法 选择择期行腔镜手术治疗的老年恶性肿瘤患者90例,随机均分为3组:对照组(C组)、体温保护组(T组)和体温保护联合右美托咪定组(T-D组),每组30例。C组常规体温保护,T组和T-D组综合体温保护;T-D组麻醉诱导前10 min泵注右美托咪定0.5 μg/kg。记录3组患者麻醉诱导开始时(T0)、手术开始30 min(T1)、60 min(T2)、90 min(T3)、120 min(T4)以及手术结束时(T5)的鼻咽温度;于T0、术后2 h(T6)、24 h(T7)和48 h(T8)时抽取静脉血标本,测定T淋巴细胞亚群(CD3+、CD4+和CD8+)和自然杀伤细胞(NK cell)水平;记录患者术中麻醉药物用量及苏醒期质量指标。结果 与T0比较,C组T2~T5时点鼻咽温度均明显降低(P < 0.05);与C组比较,T组和T-D组T2~T5时点鼻咽温度明显升高(P < 0.05)。与T0时点比较,C组、T组和T-D组T6、T7和T8时点CD3+和NK cell活性均明显降低(P < 0.05);C组在T6、T7和T8时点,T组和T-D组在T6和T7时点,CD4+活性均明显降低(P < 0.05)。与C组比较,T组和T-D组T6和T7时点CD3+细胞活性均明显升高(P < 0.05);T组在T7时点,T-D组在T6和T7时点,CD4+细胞活性均明显升高(P < 0.05);T组在T7时点,T-D组在T6、T7和T8时点,NK cell活性均明显升高(P < 0.05)。结论 采用体温保护措施联合右美托咪定能够维持老年恶性肿瘤患者的体温稳定,减少围手术期意外低体温(IPH)的发生,并有效提高患者苏醒期质量,减轻免疫抑制程度,加速患者早期恢复。  相似文献   
6.
BackgroundOne in two people with multiple sclerosis (PwMS) will fall in a three-month period. Predicting which patients will fall remains a challenge for clinicians. Standardized functional assessments provide insight into balance deficits and fall risk but their use has been limited to supervised visits.Research questionThe study aim was to characterize unsupervised 30-second chair stand test (30CST) performance using accelerometer-derived metrics and assess its ability to classify fall status in PwMS compared to supervised 30CST.MethodsThirty-seven PwMS (21 fallers) performed instrumented supervised and unsupervised 30CSTs with a single wearable sensor on the thigh. In unsupervised conditions, participants performed bi-hourly 30CSTs and rated their balance confidence and fatigue over 48-hours. ROC analysis was used to classify fall status for 30CST performance.ResultsNon-fallers (p = 0.02) but not fallers (p = 0.23) differed in their average unsupervised 30CST performance (repetitions) compared to their supervised performance. The unsupervised maximum number of 30CST repetitions performed optimized ROC classification AUC (0.79), accuracy (78.4%) and specificity (90.0%) for fall status with an optimal cutoff of 17 repetitions.SignificanceBrief durations of instrumented unsupervised monitoring as an adjunct to routine clinical assessments could improve the ability for predicting fall risk and fluctuations in functional mobility in PwMS.  相似文献   
7.
The purpose of this study is to show a very rare complication of acute cocaine poisoning, namely heart rupture. In the present case report, acute cocaine intoxication caused massive myocardial infarction, resulting in heart rupture and cardiac tamponade. A crime scene investigation found a dead body on the street in a drug dealing district. Examination of the body showed no external injuries. A thorough autopsy was performed showing massive cardiac tamponade with 510 ml of blood within the pericardium and full-thickness tissue lesion at the posterior wall of the left ventricle of 3.5 × 3 cm. Histological examination in hematoxylin and eosin was performed and confirmed the interruption of the posterior wall of the left ventricle with the presence of blood. In fact, although the correlation between cocaine and myocardial damage is well established, the relationship between heart rupture and acute cocaine intoxication is an extremely rare event. Moreover, since there are, to date, few reports of similar deaths, our report provides useful information regarding sudden death in a cocaine abuser. It is, therefore, of crucial importance to report this case to the scientific community.  相似文献   
8.
9.
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   
10.
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   
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