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   5762篇
  免费   305篇
  国内免费   56篇
耳鼻咽喉   42篇
儿科学   117篇
妇产科学   31篇
基础医学   655篇
口腔科学   142篇
临床医学   379篇
内科学   1368篇
皮肤病学   105篇
神经病学   454篇
特种医学   163篇
外科学   1182篇
综合类   25篇
预防医学   138篇
眼科学   51篇
药学   363篇
中国医学   16篇
肿瘤学   892篇
  2024年   12篇
  2023年   76篇
  2022年   156篇
  2021年   262篇
  2020年   141篇
  2019年   200篇
  2018年   222篇
  2017年   130篇
  2016年   171篇
  2015年   151篇
  2014年   196篇
  2013年   236篇
  2012年   373篇
  2011年   388篇
  2010年   205篇
  2009年   167篇
  2008年   245篇
  2007年   292篇
  2006年   258篇
  2005年   264篇
  2004年   226篇
  2003年   207篇
  2002年   223篇
  2001年   120篇
  2000年   109篇
  1999年   132篇
  1998年   59篇
  1997年   48篇
  1996年   38篇
  1995年   24篇
  1994年   33篇
  1993年   25篇
  1992年   67篇
  1991年   80篇
  1990年   69篇
  1989年   83篇
  1988年   73篇
  1987年   45篇
  1986年   43篇
  1985年   40篇
  1984年   27篇
  1983年   26篇
  1982年   21篇
  1980年   15篇
  1979年   29篇
  1978年   19篇
  1977年   15篇
  1974年   10篇
  1972年   10篇
  1971年   8篇
排序方式: 共有6123条查询结果,搜索用时 15 毫秒
81.
Takayasu arteritis results in a variety of vascular symptoms, and there are some cases in which progressive vascular lesions require surgical intervention. We present a case with ascending aortic aneurysm, right common carotid artery stenosis, left common carotid artery occlusion and left subclavian artery stenosis caused by Takayasu arteritis that was successfully treated with total arch replacement and ascending aorta to right internal carotid artery bypass.  相似文献   
82.
Recent studies have shown that angiotensin II type 1 (AT1) receptor-mediated Akt activation induces vascular smooth muscle cell (VSMC) dedifferentiation in vitro. However, the critical signal transductions affecting the VSMC phenotype remain unclear in vivo. We examined whether signal transduction through AT1 receptor-mediated reactive oxygen species (ROS) could regulate the VSMC phenotype in stroke-prone spontaneously hypertensive rats (SHRSPs). Male SHRSPs were randomized and treated for 6 weeks with a vehicle, an ACE inhibitor cilazapril, or an AT1 receptor antagonist E4177. The 2 drugs showed equipotent effects on the blood pressure, aortic morphology, and collagen deposition. Both drugs also significantly reduced aortic NAD(P)H oxidase activity and p38MAPK and ERK expression, whereas p-Akt, eNOS, and SM2 were significantly increased in SHRSP aortas. Furthermore, E4177 was more effective than cilazapril at inducing VSMC differentiation by reducing NAD(P)H oxidase activity, and up-regulating p-Akt, eNOS, and SM2. Thus, an ACE inhibitor and an AT1 receptor antagonist inhibited VSMC dedifferentiation through inhibition of NAD(P)H oxidase activity and up-regulation of eNOS and Akt in SHRSP aortas, suggesting that in contrast to the in vitro experiments, AT1 receptor-mediated NAD(P)H oxidase-generated ROS, eNOS, and Akt might be crucial determinants for the VSMC phenotype in hypertension in vivo.  相似文献   
83.

Objectives

A combination of platinum-based chemotherapy and radiotherapy is the standard treatment for nasopharyngeal carcinoma (NPC). However, the efficacy of chemotherapy has reached a plateau. Many autophagy studies suggest that autophagy can either promote or suppress to cancer progression. Thus, a role of autophagy in the acquisition of chemoradioresistance has recently been a notable event. Therefore, we examined the relationship between autophagy and chemotherapy in NPC.

Methods

The expression of Beclin 1 and microtubule-associated protein light chain 3 (LC3), a marker of autophagy, was determined by immunohistochemistry in the biopsy samples of patients with NPC before and after the first course of chemotherapy. Additionally, to investigate in the effect of autophagy suppression in chemotherapy, NPC cell line C666-1 cells were treated with cisplatin and/or chloroquine, an inhibitor of autophagy.

Results

The expression of Beclin 1 increased after chemotherapy in all patients. In NPC cell line C666-1, compared to cisplatin alone, combination therapy (cisplatin and chloroquine) reduced cell viability, and promoted cell apoptosis.

Conclusions

These results suggest that autophagy, represented by Beclin 1, is upregulated after chemotherapy in both in vitro and in vivo NPC studies. Inhibition of autophagy could therefore be new strategy for NPC treatment.  相似文献   
84.
85.
Massive hemoptysis is a fatal complication associated with pulmonary tuberculosis (TB). It can lead to severe respiratory failure. Extracorporeal membrane oxygenation (ECMO) is a life-saving technology that is rarely indicated for bleeding disorders. We herein report a 26-year-old man who presented with severe respiratory failure caused by massive hemoptysis with pulmonary TB. Transcatheter artery embolization was successfully performed with venovenous ECMO support. The hemostatic procedure allowed concomitant anticoagulant use, and neither bleeding nor thrombotic complications occurred throughout the clinical course. Administering the appropriate hemostatic procedure with subsequent management, including anticoagulant therapy, supported ECMO application in a case of bleeding.  相似文献   
86.
Priming exercises improve subsequent motor performance; however, their effectiveness may depend on the workload and involved body areas. The present study aimed to estimate the effects of leg and arm priming exercises performed at different intensities on maximal sprint cycling performance. Fourteen competitive male speed-skaters visited a lab eight times, where they underwent a body composition measurement, two V̇O2max measurements (leg and arm ergometers), and five sprint cycling sessions after different priming exercise conditions. The five priming exercise conditions included 10-minute rest (Control); 10-minute arm ergometer exercise at 20% V̇O2max (Arm 20%); 10-minute arm ergometer exercise at 70% V̇O2max (Arm 70%); 1-min maximal arm ergometer exercise at 140% V̇O2max (Arm 140%); and 10-min leg ergometer exercise at 70% V̇O2max (Leg 70%). Power outputs of 60-s maximal sprint cycling, blood lactate concentration, heart rate, muscle and skin surface temperature, and rating of perceived exertion were compared between the priming conditions at different measurement points. Our results showed that the Leg 70% was the optimal priming exercise among our experimental conditions. Priming exercise with the Arm 70% also tended to improve subsequent motor performance, while Arm 20% and Arm 140% did not. Mild elevation in blood lactate concentration by arm priming exercise may improve the performance of high-intensity exercise. Key points
  • Maximal sprint cycling performance was comparable between the Arm 70% condition and the Leg 70% condition
  • A mild elevation in BLC by arm priming exercise may improve the performance of high-intensity exercise
  • Low (i.e., Arm 20%) and high (i.e., Arm 140%) workloads did not provide any performance benefits
Key words: Exercise, arm, heart rate, lactic acid  相似文献   
87.
BackgroundThe burden of COVID-19 on healthcare workers (HCWs) is reported to be increasing, yet the psychometric scales now in use evaluate only single aspects; few measure the pandemic-specific burden on HCWs comprehensively.ObjectiveTo develop a scale to quantify the physical, mental, and socioeconomic burden of the COVID-19 pandemic on HCWs.DesignScale development and cross-sectional survey.ParticipantsConsenting HCWs aged ≥20.Main MeasuresDevelopment of an item-list based on literature reviews and HCW panel input, evaluation of content validity and item selection using the Delphi method, psychometric testing conducted on HCWs, validity assessment by factor analyses and hypothesis verification, internal consistency evaluation by Cronbach’s alpha, test-retest analysis, and interpretability assessment.Key ResultsThrough the Delphi process, a 29-item pilot scale was generated. In psychometric testing, data from 863 HCWs contributed to the development of the final version of this scale, called Pandemic Burden Index twenty for HCWs (PBI-20), a 20-item scale to measure six domains: fatigue, fear of infection, inadequacy as a medical professional, mental health concerns, prejudice or discrimination, and anxiety about one’s livelihood and daily life. Factor analysis showed each factor corresponded to the six domains of this scale. Hypothesis verification showed the PBI-20 total score to be moderately to highly correlated with the Short Form 36 vitality score and mental health score and with intention of turnover. The PBI-20 had good internal consistency (Cronbach’s alpha 0.92). Test-retest analysis showed the intraclass correlation coefficient to be 0.70 and the minimal important change to be −7.0.ConclusionsThe psychometrically sound questionnaire we developed to measure pandemic-specific burdens for HCWs provides an understanding of comprehensive burdens on HCWs and may serve to evaluate interventions to reduce the burdens.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-023-08028-3.KEY WORDS: COVID-19, pandemic, burden, health personnel, psychometrics  相似文献   
88.
Guillain-Barré syndrome (GBS) has occasionally occurred in people who have received coronavirus disease 2019 (COVID-19) vaccines. Dysgeusia is rare symptom of GBS. We herein report a rare case of sensory ataxic GBS with dysgeusia just after the second dose of the Pfizer-BioNTech COVID-19 vaccine. Although autoantibodies against glycolipids were not detected, immunotherapy with intravenous immunoglobulin and methylprednisolone pulse therapy effectively ameliorated the symptoms. Our report suggests that the COVID-19 vaccine may induce various clinical subtypes of GBS, including a rare variant with sensory ataxia and dysgeusia.  相似文献   
89.
A 39-year-old woman was hospitalized for nephrotic syndrome. Laboratory test results showed increased serum creatinine levels and urinary excretions of beta-2-microglobulin, and N-acetyl-beta-D-glucosaminidase. A renal biopsy revealed collapsing focal segmental glomerulosclerosis (FSGS) and acute interstitial nephritis. Despite treatment with pulse steroid followed by oral high-dose glucocorticoids and cyclosporines, heavy proteinuria persisted. After low-density lipoprotein apheresis (LDL-A) therapy was initiated, her proteinuria gradually decreased, leading to complete remission. A repeat renal biopsy after treatment revealed no collapsing glomeruli. Immediate LDL-A should be performed to treat cases of collapsing FSGS poorly responding to other treatments.  相似文献   
90.
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