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   9112篇
  免费   694篇
  国内免费   261篇
耳鼻咽喉   140篇
儿科学   155篇
妇产科学   147篇
基础医学   1078篇
口腔科学   660篇
临床医学   847篇
内科学   1108篇
皮肤病学   321篇
神经病学   928篇
特种医学   617篇
外国民族医学   3篇
外科学   830篇
综合类   1325篇
现状与发展   1篇
预防医学   334篇
眼科学   112篇
药学   540篇
  8篇
中国医学   255篇
肿瘤学   658篇
  2023年   143篇
  2022年   277篇
  2021年   396篇
  2020年   356篇
  2019年   308篇
  2018年   276篇
  2017年   322篇
  2016年   364篇
  2015年   330篇
  2014年   676篇
  2013年   617篇
  2012年   533篇
  2011年   562篇
  2010年   423篇
  2009年   375篇
  2008年   371篇
  2007年   338篇
  2006年   300篇
  2005年   248篇
  2004年   217篇
  2003年   212篇
  2002年   143篇
  2001年   154篇
  2000年   118篇
  1999年   119篇
  1998年   113篇
  1997年   105篇
  1996年   111篇
  1995年   111篇
  1994年   92篇
  1993年   77篇
  1992年   70篇
  1991年   78篇
  1990年   60篇
  1989年   67篇
  1988年   55篇
  1987年   46篇
  1986年   41篇
  1985年   88篇
  1984年   102篇
  1983年   67篇
  1982年   80篇
  1981年   68篇
  1980年   88篇
  1979年   56篇
  1978年   53篇
  1977年   51篇
  1976年   60篇
  1974年   30篇
  1973年   40篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
We studied the synergistic effects of pergolide and bromocriptine with caffeine on turning behavior in 6-OHDA denervated rats. Both pergolide and bromocriptine were synergistic with caffeine, and prevented tolerance to caffeine-induced turning. When caffeine was removed, tolerance to bromocriptine effects was observed for 1 day only, while no tolerance was observed to pergolide. These results suggest that caffeine could be useful in the treatment of Parkinson's disease, preferentially as an adjuvant of mixed dopaminergic agonists like pergolide.  相似文献   
112.
A CT-based method of marking superficial intracranial lesions with a needle is presented. This form of neuronavigation can be applied in every neurosurgical centre. Owing to its rapid application it is also suitable for cases of emergency. The neurosurgical approach can be centred precisely over the lesion providing for a minimally invasive operation. The method has proved its efficacy in numerous cases of haematomas and cystic lesions.  相似文献   
113.
CT三维容积重建在颌骨疾病诊治中的应用   总被引:2,自引:0,他引:2  
目的 评价CT三维容积重建在颌面骨病变诊治中的应用价值。方法 用MX 80 0 0双排螺旋CT机的 4D Angio软件处理容积数据得到高度仿真的三维CT ,可直观清晰地显示颌骨病变的部位、范围、程度及其与邻近结构的关系 ,有利临床作出准确诊断 ,正确选择手术方法和确定手术进路。结果 CT三维容积重建可以直观地显示颌合骨的复杂结构及其病变的整体形态 ,对骨折复位和病变彻底切除起到重要作用。结论 与常规断面CT以及三维表面遮蔽 (SSD)重建相比 ,MX 80 0 0的 4D Angio软件 (相当于volumerender ing软件 ,即VR)做出的CT三维容积重建 (VR)更有立体感 ,更能展现解剖结构的自然形态 ,而且其为容积数据的全息处理 ,可显示骨质内部结构 ,因而能为临床提供更直观 ,详实的形态学资料 ,便于确诊并可优化手术方案和最大限度减少手术创伤 ,有利于功能和形态的更好恢复  相似文献   
114.
目的 探讨直径〈3cm的肾脏小占位病变的常见类型、影像学特征和常规诊疗步骤。方法 回顾性分析1998年1月至2005年10月间偶然发现的58例〈3cm的肾脏占位病变的临床资料。结果 58例患者共发现肾脏占位病变70个。直径〈1cm的占位病变5个,1~2cm为11个,2~3cm为54个。B超发现囊性占位36个,实质性占位34个,其中高回声占位21个,等回声占位4个,低回声占位9个。增强CT明显强化的病变19个,轻度强化20个,无明显强化31个。首诊时B超结合CT获确诊54例,未能确诊的4例,MRI、肾动脉造影及穿刺活检亦不确切。结论 对〈3cm的肾脏占位病变,B超结合CT检查可基本满足鉴别诊断的需要。少数诊断不确切的病例,腹腔镜肾部分切除术兼有诊断和治疗作用。手术耐受力差或不接受手术探查的未能确诊的患者可考虑影像学密切随访。  相似文献   
115.
中药在防治食道癌前病变、口腔癌前病变、鼻咽癌前病变、胃癌前病变、肝癌前病变和宫颈癌前病变等方面取得了显著成效,其逆转癌前病变主要是通过调节细胞周期调控基因,细胞生长、增殖、分化调控基因及相关蛋白基因,细胞凋亡基因,转录因子等表达来发挥作用,另外中药还可对端粒酶活性、DNA水平等进行调整,也可能通过改善免疫相关基因如细胞黏附分子来提高机体的抗癌变能力。  相似文献   
116.
AIM: To investigate the diffusion changes in both the optic nerve and optic tract in orbital space-occupying lesion patients with decreased visual acuity, and its clinical significance using probabilistic diffusion tractography (PDT). METHODS: Twenty patients with orbital space-occupying lesions and 25 age- and gender-matched healthy persons were included. All patients and controls underwent routine orbital magnetic resonance imaging and diffusion tensor imaging (DTI), using a 3.0T magnetic resonance scanner (Trio Tim Siemens). After the image data were preprocessed, each DTI parameters of the optic nerve and optic tract was obtained by PDT, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The asymmetry index (AI) of each parameter was calculated. Compared the parameters of the affected side optic nerve and ipsilateral optic tract with the contralateral side by paired sample t-test; compared AI of parameters of optic nerve and optic tract between the patient group and the control group by independent sample t-test. Patients were divided into three subgroups according to the low vision grade standard of WHO, compared the FA and AI of FA between the three subgroups by single factor variance analysis. RESULTS: The affected side optic nerve presented significantly decreased FA, increased MD, AD, and RD values compared to the unaffected side (P<0.05). The AI of FA, MD, AD, and RD of optic nerve in the patients was significantly higher than that of the controls (P<0.05). The comparison results of the optic tract showed that there was no significant difference between the patient group and control group in terms of the bilateral optic tracts in patients (P>0.05). The AIs of the FA value of the optic nerve in the eyesight <0.1 subgroup was significantly higher than that in the other groups (P<0.05). CONCLUSION: FA, MD, AD, and RD of the affected side optic nerve of the orbital space-occupying lesions have significantly changed, the FA value is the most sensitive. The PDT could be a useful tool to provide valid quantitative markers of optic nerve injuries and evaluate the severity of orbital diseases, which other examinations cannot be acquired.  相似文献   
117.
118.
The relationship between clinical symptoms and neurocognitive impairment has been a growing interest in the field of schizophrenia research. We review the empirical evidence for whether some schizophrenia symptoms can be viewed as expressions of disordered executive functioning. A specific focus of our review is Frith’s (1992) neurocognitive theory of negative symptoms, and whether this theory is supported by studies of executive functioning in schizophrenia. The current trend towards viewing executive functioning in terms of fractionable cognitive processes is discussed. Difficulties with traditional clinical measures (e.g. the Wisconsin Card Sorting Test; WCST) in separating these processes are highlighted. Neurocognitive studies of schizophrenia are then reviewed in terms of this fractionated view of executive processes. We conclude that a more specific approach to executive functioning deficits in schizophrenia using more selective measures is needed before stronger conclusions can be drawn about their relationship to clinical symptoms.  相似文献   
119.
BACKGROUND: Laser scar revision has been an effective method for improving several aspects of scarring through ablative and non-ablative sources. The 585-nm pulsed dye laser (PDL) is an important non-ablative instrument for reducing scar bulk and symptoms. OBJECTIVE: To describe the use of a 585-nm PDL for the treatment of a retracted and atrophic facial scar. METHODS: We report the case of a 26-year-old patient who presented with a retracted facial scar following surgical excision of an aggressive benign tumor. Treatment was carried out using the 585-nm PDL. RESULTS: Treatment of the scar using two low-level PDL therapies significantly altered the appearance of the scar and augmentation of the retracted defect was avoided. CONCLUSION: Treatment of this retracted and atrophic facial scar with the 585-nm PDL was very effective and safe.  相似文献   
120.
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