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   4345篇
  免费   419篇
  国内免费   132篇
耳鼻咽喉   641篇
儿科学   69篇
妇产科学   31篇
基础医学   457篇
口腔科学   76篇
临床医学   347篇
内科学   839篇
皮肤病学   13篇
神经病学   266篇
特种医学   127篇
外科学   265篇
综合类   643篇
预防医学   112篇
眼科学   96篇
药学   572篇
  4篇
中国医学   198篇
肿瘤学   140篇
  2023年   43篇
  2022年   58篇
  2021年   123篇
  2020年   139篇
  2019年   141篇
  2018年   130篇
  2017年   154篇
  2016年   182篇
  2015年   153篇
  2014年   268篇
  2013年   285篇
  2012年   256篇
  2011年   241篇
  2010年   183篇
  2009年   177篇
  2008年   178篇
  2007年   195篇
  2006年   187篇
  2005年   152篇
  2004年   163篇
  2003年   111篇
  2002年   134篇
  2001年   108篇
  2000年   99篇
  1999年   83篇
  1998年   81篇
  1997年   75篇
  1996年   69篇
  1995年   57篇
  1994年   48篇
  1993年   45篇
  1992年   47篇
  1991年   44篇
  1990年   42篇
  1989年   41篇
  1988年   28篇
  1987年   23篇
  1986年   26篇
  1985年   40篇
  1984年   39篇
  1983年   26篇
  1982年   33篇
  1981年   35篇
  1980年   20篇
  1979年   18篇
  1978年   25篇
  1977年   24篇
  1976年   20篇
  1975年   10篇
  1973年   11篇
排序方式: 共有4896条查询结果,搜索用时 146 毫秒
61.
The membranotropic effects of TVF tanacetan pectin polysaccharide derived from Tanacetum vulgare L. was studied by the voltage-clamp method on isolated neurons of Lymnaea stagnalis mollusk. TVF in concentrations of 0.1-10.0 µg/ml nonselectively activated the outward potassium and total inward (sodium and calcium) ionic currents (slightly dose-dependently and reversibly increased their amplitude by 5–10%) and decreased nonspecific leakage current.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 10, pp. 439–441, October, 2004  相似文献   
62.
BACKGROUND: Involvement of paranasal sinuses has been suggested in allergic rhinitis but not clearly demonstrated. AIMS: To investigate the relationship between intermittent allergic rhinitis and computerized tomography (CT). METHODS: Twenty patients with intermittent rhinitis and sensitized to cypress pollens underwent unilateral nasal provocation tests (NPTs) using increasing concentrations of cypress pollens out of the pollen season. Sinus CT-scans were carried out just before a NPT and 24 h later. Nasal lavage was carried out just before a NPT, 30 min after a positive challenge and again 24 h later. Leucotriene C4/D4, intracellular adhesion molecule-1 and eosinophil cationic protein were measured in nasal secretions. RESULTS: Thirteen patients (65%) showed an alteration in their CT-scans after allergen challenge. Ten of them showed sinus changes controlateral to their allergenic provocation. Radiological changes mainly affected the osteomeatal complex and the ethmoid sinuses. Pre-existing abnormalities (13 of 20 cases) mainly concerned the maxillary sinuses. There was no correlation between CT-scan abnormalities and levels of mediators released in nasal secretions. CONCLUSIONS: We have shown that nasal allergen challenge can produce radiological changes in the paranasal sinuses. This mainly concerned the ethmoid sinuses.  相似文献   
63.
In vitro diagnosis of chronic nasal inflammation   总被引:6,自引:0,他引:6  
BACKGROUND: Differential diagnosis of chronic nasal inflammation is insufficient when based solely on clinical examination and radiography of paranasal sinuses. Patients complain about more or less similar symptoms. Activation of mast cells and eosinophils is pivotal in nasal inflammation. OBJECTIVE: To compare tryptase and eosinophilic cationic protein (ECP) in nasal secretions in different forms of chronic nasal inflammation and to establish norm values. METHODS: The study included 1710 patients presenting with nasal complaints. Nasal secretions were gained by the cotton wool method and analysed for tryptase, as a marker of mast cell activation, and for ECP, as a marker of tissue eosinophilia and activation. Patients were grouped according to their diagnosis: chronic, non-allergic rhinosinusitis (sinusitis, n=194), non-allergic nasal polyposis (polyposis, n=138), non-allergic rhinitis with eosinophilia syndrome (NARES, n=198), isolated perennial allergic rhinitis (AR) (n=126), isolated seasonal AR (n=132), and patients allergic to both, seasonal and perennial allergens (n=193). Seven hundred and twenty-nine patients with nasal complaints due to a deviated septum and without any nasal inflammation served as controls. RESULTS: Nasal tryptase was highly significantly (P<0.001) elevated in polyposis, NARES, and in AR. ECP was highly significantly (P<0.001) elevated in all groups of patients suffering from chronic nasal inflammation. Based on our data and method we established norm values (95% confidence interval of mean value) for nasal tryptase in healthy adults, ranging from 12.0 to 18.7 ng/mL and for ECP ranging from 84.4 to 102.6 ng/mL. CONCLUSION: Mast cells and eosinophils are involved in non-allergic and allergic forms of chronic nasal inflammation. We established an in vitro assay for tryptase and ECP in nasal secretions and defined norm values based on our data and method. In vitro measurement of biological markers in nasal secretions provides important information for differential diagnosis and therapeutic strategies of chronic nasal inflammation.  相似文献   
64.
We report two cases of allergic bronchopulmonary fungal disease (ABPFD) caused by Curvularia sp and associated with allergic fungal sinusitis (AFS). Curvularia lunata was cultured in one case and Curvularia senegalensis was cultured in the other. Based on these cases and a review of the literature, we discuss unusual clinical and pathologic features that can occur in ABPFD. Unusual clinical aspects of ABPFD include associated AFS, absence of asthma, progression to Churg-Strauss angiitis and granulomatosis, concomitant hypersensitivity pneumonitis, and underlying cystic fibrosis. Atypical pathologic features that may occur in ABPFD include follicular bronchiolitis, xanthomatous bronchiolitis, limited tissue invasion, fungus balls, and association with unusual fungi. Prominent follicular bronchiolitis and xanthomatous bronchiolitis were misleading histologic features in one of our cases and led to a delay in recognition of the diagnosis. Both patients presented primarily with AFS; ABPFD was detected subsequently. This suggests that a small subset of patients with AFS may be at risk for ABPFD. The goal of this review is to increase awareness of unusual clinical and pathologic manifestations of ABPFD. It is hoped that this will result in accurate diagnosis and proper therapy, especially for patients who present with atypical features. Unusual fungal species should be considered in patients who have clinical findings compatible with ABPFD but who do not demonstrate immunologic reactivity to Aspergillus sp, especially Aspergillus fumigatus. In addition, ABPFD should be considered in patients with AFS who develop new pulmonary lesions.  相似文献   
65.
Macrophage mannose receptor in chronic sinus disease   总被引:2,自引:0,他引:2  
BACKGROUND: The role of infectious agents in the onset and maintenance of chronic sinus disease is still not fully understood. Macrophage mannose receptor (MMR), an innate pattern recognizing receptor, capable of phagocytosis of invaders and signal transduction for proinflammatory mechanisms, might be of importance in immune interactions in chronic sinus disease. OBJECTIVE: We examined the MMR in sinonasal airway mucosa to evaluate its possible role in chronic rhinosinusitis (CS) and nasal polyposis (NPs). METHODS: Surgical samples from patients with sinonasal disease were investigated with real-time RT-PCR for quantification of MMR mRNA expression, and the presence and location of MMR-positive cells was analysed by immunohistochemistry. RESULTS: Quantification of MMR mRNA showed a statistically significant higher expression in NPs compared to CS without NP and controls. Immunohistochemistry revealed expression of MMR in all tissue samples; however, in NP we found an enhanced positive cellular staining including cell aggregates. CONCLUSIONS: We could demonstrate for the first time that the expression of MMR is significantly upregulated in NP compared to patients with CS without NP or turbinate tissue of controls. Macrophages expressing MMR, accumulated in cell aggregates in NPs, play a possible key role in pathogen-macrophage interaction in NP disease.  相似文献   
66.
目的 探讨蝶窦垂体腺瘤(sphenoid sinus pituitary adenoma,SSPA)的临床病理特征,提高对蝶窦垂体腺瘤的认识和病理诊断水平.方法 对12例SSPA进行临床、组织病理学和SP法免疫组化染色(PRL、hGH、ACTH、LH、TSH、FSH等).结果 12例SSPA,男5例,女7例,年龄39~66岁,平均48.4岁,中位年龄55.5岁.其中原发于蝶窦和原发于垂体窝侵至蝶窦者各6例,原发于蝶窦者年龄较原发于垂体窝者偏大.临床症状多样.镜下,原发于蝶窦的垂体腺瘤的形态学与蝶鞍垂体腺瘤相同;SSPA可伴有较明显的慢性炎症细胞浸润(2/12,16.67%).10例行免疫组织化学染色的结果,瘤细胞PRL阳性6例;瘤细胞各项标记物均阴性2例;瘤细胞ACTH阳性、hGH阳性各1例.结论原发于蝶窦的垂体腺瘤比较少见,主要根据光镜及免疫组化确诊,应注意与慢性蝶窦炎和浆细胞瘤鉴别.  相似文献   
67.
Summary The addition of 3-aminobenzamide (a potent inhibitor of poly(ADP-ribose)synthetase) into the incubation medium, prevents streptozotocin-induced inhibition of glucose-stimulated insulin release from isolated islets [control 142±14U·islet–1·h–1; streptozotocin (0.5mg/ml) 31±8; 3-aminobenzamide (l.0 mg/ml) 96±11; streptozotocin plus 3-aminobenzamide 122±19]. In vivo, intraperitoneal 3-aminobenzamide 300 mg/kg body weight prevents the appearance of overt diabetes in streptozotocin-treated rats. These protective effects of 3-aminobenzamide are dose-dependent and are similar to those exerted by nicotinamide. Taking into account that poly ADP-ribosylation is involved in the repair of damaged DNA, the protection exerted by 3-aminobenzamide against the diabetogenic effect of streptozotocin strongly supports the view that this acute effect may be a major consequence of the activation of DNA repair mechanisms in islet cells.  相似文献   
68.
木贼对大鼠心功能的影响   总被引:2,自引:0,他引:2  
目的:研究木贼对心脏功能的影响。方法:建立新式离体作功心脏模型。用上海产SJ-42型四道生理记录仪测定生理参数左室收缩压(LVSP)、左室内压上升速率最大值(dP/dtmax)、左室舒张期末压(LVEDP)、左室内压下降速率最大值(-dP/dtmax)、冠脉流量(CF)、心率(HR)和心电图(ECG)。结果:经过适当剂量木贼药液灌注后的离体作功心脏与用药前自身对照比较,LVSP、dP/dtmax、-dp/dtmax、CF增大,而HR变慢,经随机区组方差分析,均有显著差异。结论:木贼有增强心脏收缩与舒张功能,有增加冠脉流量和减慢心率的作用。  相似文献   
69.
目的:探讨综合治疗多发性鼻息肉的疗效。方法;对多发性鼻息肉72例进行综合治疗即行鼻息肉摘除术+筛窦开放术+术后随诊治疗3个月。随访1-6年。结果:治愈51例,复发21例,治愈率为70.8%。结论:此方法能有效地降低鼻息肉的复发率,消除鼻窦炎的症状,如多脓涕、头痛等。疗效比常规单纯鼻息肉摘除持久。  相似文献   
70.
金祎敏  谢燕  王东帆  章晨峰  曹亮  谢雪  肖伟  王振中  吕耀中 《中草药》2023,54(22):7482-7488
目的 从桂枝茯苓胶囊(Guizhi Fuling Capsules,GZFLC)临床用于治疗痛经的功效出发,探索建立基于子宫平滑肌收缩活性测定的GZFLC质量生物活性评价方法。方法 通过注射雌激素增加小鼠子宫敏感性,建立缩宫素诱导的小鼠离体子宫平滑肌收缩模型,采集给药前后小鼠子宫平滑肌的收缩频率、幅值和峰面积,以收缩峰面积为指标进行统计并对药效进行归一化处理。考察小鼠离体子宫平滑肌收缩模型的主要影响因素如雌激素注射方式与天数、缩宫素浓度、动物周龄和GZFLC前处理方法。建立GZFLC质量生物活性评价方法并进行方法学考察,测定10个批次GZFLC合格样品及2个GZFLC高温破坏样品的生物活性。结果 连续3 d ip雌激素10 mg/(kg·d)后小鼠子宫平滑肌收缩峰面积较高且收缩节律较好;最适缩宫素造模质量浓度为0.050 μg/mL;将GZFLC配制成质量浓度为0.125 g/mL的药液并超声溶解60 min有利于药效发挥;重复性考察RSD为11.298%,日内精密度RSD为12.452%,日间精密度RSD为10.438%;10批次GZFLC半数抑制浓度(half inhibitory concentration,IC50)为1.526~1.631 mg/mL,高温破坏后GZFLC的IC50明显增大。结论 基于子宫平滑肌收缩活性测定的GZFLC质量评价方法重复性和精密度较好,为后续GZFLC的综合质量评价标准建立提供了科学依据。  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