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   7504篇
  免费   447篇
  国内免费   104篇
耳鼻咽喉   105篇
儿科学   117篇
妇产科学   144篇
基础医学   808篇
口腔科学   274篇
临床医学   636篇
内科学   2301篇
皮肤病学   142篇
神经病学   620篇
特种医学   259篇
外科学   1244篇
综合类   27篇
一般理论   2篇
预防医学   299篇
眼科学   68篇
药学   369篇
中国医学   15篇
肿瘤学   625篇
  2024年   17篇
  2023年   143篇
  2022年   276篇
  2021年   494篇
  2020年   289篇
  2019年   320篇
  2018年   361篇
  2017年   259篇
  2016年   299篇
  2015年   311篇
  2014年   410篇
  2013年   449篇
  2012年   640篇
  2011年   570篇
  2010年   308篇
  2009年   309篇
  2008年   429篇
  2007年   388篇
  2006年   358篇
  2005年   295篇
  2004年   225篇
  2003年   196篇
  2002年   151篇
  2001年   60篇
  2000年   46篇
  1999年   40篇
  1998年   34篇
  1997年   23篇
  1996年   24篇
  1995年   20篇
  1994年   20篇
  1992年   21篇
  1991年   16篇
  1990年   18篇
  1989年   30篇
  1988年   26篇
  1987年   18篇
  1986年   15篇
  1985年   13篇
  1983年   9篇
  1979年   9篇
  1978年   9篇
  1977年   8篇
  1974年   16篇
  1973年   7篇
  1972年   7篇
  1971年   8篇
  1970年   8篇
  1969年   8篇
  1966年   7篇
排序方式: 共有8055条查询结果,搜索用时 15 毫秒
41.
42.
Torpor is a naturally occurring, hypometabolic, hypothermic state engaged by a wide range of animals in response to imbalance between the supply and demand for nutrients. Recent work has identified some of the key neuronal populations involved in daily torpor induction in mice, in particular, projections from the preoptic area of the hypothalamus to the dorsomedial hypothalamus (DMH). The DMH plays a role in thermoregulation, control of energy expenditure, and circadian rhythms, making it well positioned to contribute to the expression of torpor. We used activity-dependent genetic TRAPing techniques to target DMH neurons that were active during natural torpor bouts in female mice. Chemogenetic reactivation of torpor-TRAPed DMH neurons in calorie-restricted mice promoted torpor, resulting in longer and deeper torpor bouts. Chemogenetic inhibition of torpor-TRAPed DMH neurons did not block torpor entry, suggesting a modulatory role for the DMH in the control of torpor. This work adds to the evidence that the preoptic area of the hypothalamus and the DMH form part of a circuit within the mouse hypothalamus that controls entry into daily torpor.SIGNIFICANCE STATEMENT Daily heterotherms, such as mice, use torpor to cope with environments in which the supply of metabolic fuel is not sufficient for the maintenance of normothermia. Daily torpor involves reductions in body temperature, as well as active suppression of heart rate and metabolism. How the CNS controls this profound deviation from normal homeostasis is not known, but a projection from the preoptic area to the dorsomedial hypothalamus has recently been implicated. We demonstrate that the dorsomedial hypothalamus contains neurons that are active during torpor. Activity in these neurons promotes torpor entry and maintenance, but their activation alone does not appear to be sufficient for torpor entry.  相似文献   
43.
Coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 is associated with a wide spectrum of disease, ranging from asymptomatic infection to acute respiratory distress syndrome. Some biomarkers may predict disease severity. Among them, the anti-SARS-CoV-2 antibody response has been related to severe disease. The aim of this study was to assess the correlation between the anti-SARS-CoV-2 serological response and COVID-19 outcome. Demographic, clinical, and biological data from nasopharyngeal-PCR confirmed COVID-19 hospitalized patients were prospectively collected between April and August 2020 at our institution. All patients had serial weekly serology testing for a maximum of three blood samples or until discharge. Two different serological assays were used: a chemiluminescent assay and an in-house developed Luminex immunoassay. Kinetics of the serological response and correlation between the antibody titers and outcome were assessed. Among the 70 patients enrolled in the study, 22 required invasive ventilation, 29 required non-invasive ventilation or oxygen supplementation, and 19 did not require any oxygen supplementation. Median duration of symptoms upon admission for the three groups were 13, 8, and 9 days, respectively. Antibody titers gradually increased for up to 3 weeks since the onset of symptoms for patients requiring oxygen supplementation with significantly higher antibody titers for patients requiring invasive ventilation. Antibody titers on admission were also significantly higher in severely ill patients and serology performed well in predicting the necessity of invasive ventilation (AUC: 0.79, 95% CI: 0.67–0.9). Serology testing at admission may be a good indicator to identify severe COVID-19 patients who will require invasive mechanical ventilation.  相似文献   
44.
Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the clinical outcomes of vitrectomy with induction of posterior vitreous detachment for the treatment of optic disc...  相似文献   
45.
ABSTRACT

Introduction: One-third of breast cancer (BC) cases worldwide occur in women aged 65 years and older, with 10 to 15% overexpressing the human epidermal growth factor receptor 2 (HER2). Although several HER2-targeted therapies have been developed, the lack of data regarding their use in older patients hampers evidence-based decision-making for this population.

Areas Covered: We review current evidence on the efficacy and safety of HER2-targeted therapies in older adults with BC, focusing on approved therapies such as trastuzumab, lapatinib, pertuzumab, ado-trastuzumab-emtansine, and neratinib. Additionally, we discuss drugs under development to target the HER2-receptor, and to overcome resistance to existing therapies. Finally, we highlight the cardiotoxicity of HER2-targeted drugs among older adults.

Expert Opinion: Older adults are underrepresented in trials of HER2-targeted therapies in BC. We propose strategies to increase recruitment of older adults in clinical trials in order to increase the evidence base to treat this growing population.  相似文献   
46.
Antioxidant properties of ursodeoxycholic acid   总被引:5,自引:0,他引:5  
We have investigated potential antioxidant properties of the clinically relevant bile acid UDCA, which reaches therapeutic concentrations up to 0.09 and 29 mM, respectively, in human plasma and bile. UDCA was an excellent scavenger of OHz.rad; generated by FeCl(3)-EDTA, H(2)O(2) and ascorbate in the deoxyribose oxidation test, showing IC(min) and IC(50) values of 0.02 and 0.2 mM, respectively, and a second-order rate constant for reaction with OHz.rad; of 2+/-0.1 x 10(10)M(-1)s(-1). Notably, the drug could enhance at 1.5 mM concentration the antioxidant capacity of human bile against OHz.rad;-induced deoxyribose oxidation. UDCA also showed antioxidant effects in the deoxyribose test performed with nonchelated iron ions, such as Fe(2+) plus H(2)O(2) (IC(min): 7 mM, IC(50): 20 mM) or Fe(3+) plus H(2)O(2) and ascorbate (IC(min): 0.3 mM, IC(50): 5 mM), and inhibited ferrozine-Fe(2+) and desferrioxamine-Fe(3+) complexes formation with IC(50) values of, respectively, 12 and 0.3 mM, indicating that the drug interacts more with iron(III) than with iron(II). Moreover, UDCA significantly inhibited phospholipid liposome peroxidation induced by the OHz.rad;-generating system FeCl(3)-EDTA, H(2)O(2) and ascorbate (IC(min): 0.75 mM, IC(50): 3 mM), and by peroxyl radicals generated in the aqueous phase by AAPH (IC(min): 8 mM, IC(50): 14 mM). UDCA, even at 25 mM concentration, was ineffective on the lipoperoxidation mediated by Fe(2+) alone, but at the same concentration counteracted significantly that by Fe(3+) plus ascorbate, further pointing to its preferential antioxidant interaction with iron(III).In conclusion, UDCA has direct antioxidant properties, which are especially relevant against Fe(3+)- and OHz.rad;-dependent biomolecular oxidative damage; such properties are evident at therapeutically relevant drug concentrations, suggesting that UDCA could act as an antioxidant in vivo.  相似文献   
47.
BACKGROUND: Giant myomas of the uterus are uncommon, particularly in developed countries. CASE: This report illustrates a case of a woman with a bilobated giant myoma of the uterus weighed in total 27.7 kg. The patient had an abdominal distension first noted 18 months before and the personal history evidenced difficulties in walking and tiredness. Abdominal hysterectomy and bilateral salpingo-oophorectomy were carried out. CONCLUSIONS: The knowledge of the different clinical manifestation of these myomas may allow to face that with adequate perioperative care, in order to assure a carefully and successfully surgery, although sometimes a benign pathology may be not easy to suspect in a first time.  相似文献   
48.
目的探讨门冬胰岛素30联合拜糖平治疗初诊2型糖尿病的临床疗效。方法100例初诊2型糖尿病患者随机分为观察组与对照组各50例。对照组给予门冬胰岛素30治疗,观察组给予门冬胰岛素30联合拜糖平治疗,比较两组血糖控制效果。结果治疗16周后,观察组空腹血糖(FPG)、餐后2h血糖(2hPG)比对照组降低更加明显(P〈0.05),每日胰岛素用量比对照组更少。结论门冬胰岛素30联合拜糖平治疗初诊2型糖尿病可有效控制血糖,减少胰岛素用量。  相似文献   
49.
The major therapeutic goal for immune thrombocytopenic purpura (ITP) is to restore normal platelet counts using drugs to promote platelet production or by interfering with mechanisms responsible for platelet destruction. Eighty percent of patients with ITP possess anti–integrin αIIbβ3 IgG autoantibodies that cause platelet opsonization and phagocytosis. The spleen is considered the primary site of autoantibody production by autoreactive B cells and platelet destruction. The immediate failure in approximately 50% of patients to recover a normal platelet count after anti-CD20 rituximab-mediated B cell depletion and splenectomy suggests that autoreactive, rituximab-resistant, IgG-secreting B cells (IgG-SCs) reside in other anatomical compartments. We analyzed more than 3,300 single IgG-SCs from spleen, bone marrow, and/or blood of 27 patients with ITP, revealing high interindividual variability in affinity for αIIbβ3, with variations over 3 logs. IgG-SC dissemination and range of affinities were, however, similar for each patient. Longitudinal analysis of autoreactive IgG-SCs upon treatment with the anti-CD38 mAb daratumumab demonstrated variable outcomes, from complete remission to failure with persistence of high-affinity anti–αIIbβ3 IgG-SCs in the bone marrow. This study demonstrates the existence and dissemination of high-affinity autoreactive plasma cells in multiple anatomical compartments of patients with ITP that may cause the failure of current therapies.  相似文献   
50.
Assessing maximum voluntary bite force is important to characterize the functional state of the masticatory system. Due to several factors affecting the estimation of the maximum bite force, a unique solution combining desirable features such as reliability, accuracy, precision, usability, and comfort is not available. The aim of the present study was to develop a low-cost bite force measurement device allowing for subject-specific customization, comfortable bite force expression, and reliable force estimation over time. The device was realized using an inexpensive load cell, two 3D printed ergonomic forks hosting reusable subject-specific silicone molds, a read-out system based on a low-cost microcontroller, and a wireless link to a personal computer. A simple model was used to estimate bite force taking into account individual morphology and device placement in the mouth. Measurement reliability, accuracy, and precision were assessed on a calibration dataset. A validation procedure on healthy participants was performed to assess the repeatability of the measurements over multiple repetitions and sessions. A 2% precision and 2% accuracy were achieved on measurements of forces in the physiological range of adult bite forces. Multiple recordings on healthy participants demonstrated good repeatability (coefficient of variation 11%) with no significant effect of repetition and session. The novel device provides an affordable and reliable solution for assessing maximum bite force that can be easily used to perform clinical evaluations in single sessions or in longitudinal studies.  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