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   1806篇
  免费   103篇
  国内免费   8篇
耳鼻咽喉   16篇
儿科学   99篇
妇产科学   37篇
基础医学   188篇
口腔科学   35篇
临床医学   112篇
内科学   397篇
皮肤病学   13篇
神经病学   105篇
特种医学   221篇
外科学   246篇
综合类   56篇
一般理论   1篇
预防医学   73篇
眼科学   68篇
药学   141篇
中国医学   3篇
肿瘤学   106篇
  2023年   11篇
  2022年   14篇
  2021年   41篇
  2020年   26篇
  2019年   34篇
  2018年   42篇
  2017年   22篇
  2016年   30篇
  2015年   27篇
  2014年   58篇
  2013年   68篇
  2012年   96篇
  2011年   109篇
  2010年   64篇
  2009年   62篇
  2008年   87篇
  2007年   101篇
  2006年   74篇
  2005年   70篇
  2004年   68篇
  2003年   60篇
  2002年   42篇
  2001年   47篇
  2000年   58篇
  1999年   42篇
  1998年   25篇
  1997年   26篇
  1996年   20篇
  1995年   22篇
  1994年   11篇
  1993年   16篇
  1992年   19篇
  1991年   25篇
  1990年   25篇
  1989年   32篇
  1988年   33篇
  1987年   23篇
  1986年   28篇
  1985年   20篇
  1984年   22篇
  1983年   17篇
  1982年   13篇
  1979年   24篇
  1978年   20篇
  1977年   17篇
  1976年   13篇
  1973年   12篇
  1972年   12篇
  1970年   10篇
  1966年   10篇
排序方式: 共有1917条查询结果,搜索用时 15 毫秒
71.
Dentascan in oral imaging   总被引:5,自引:0,他引:5  
In the past, dental disease and lesions involving the jaw were either evaluated by plain radiography or tomography. The advent of spiral computed tomography (CT) and DentaScan is changing the imaging trend. It is now not only used for pre-implant assessment but also in the diagnosis of lesions affecting the jaw. This pictorial review discusses the role of DentaScan in the various abnormalities that may affect the mandible and maxilla.  相似文献   
72.
Does anybody know how we should measure Doppler parameters in lymph nodes?   总被引:6,自引:0,他引:6  
AIM: To show how currently described techniques confuse interpretation of Doppler indices in lymph node characterization. MATERIALS AND METHODS: The Doppler indices [resistivity index (RI) and pulsatility index (PI)] were obtained in 35 malignant lymph nodes by colour duplex sonography. Each node was sampled at eight different sites. Data were analysed using our own method, and methods employed in six previous studies. RESULTS: Restistivity index values varied between 0.69 and 0.88 and PI values ranged from 1.28 to 2.34. All but two methods produced different resistance indices (P < 0.05). CONCLUSION: Conflicting results are obtained analysing the same data using different methods. Standardized techniques should be agreed and employed in future studies.  相似文献   
73.
74.
Full‐arch, fixed, implant‐supported prostheses can be designed to be cement‐ or screw‐retained. Both retention mechanisms have a few inherent disadvantages. A fixed attachment system has been introduced to circumvent the disadvantages of both screw and cement retention. This system eliminates the screw access holes and the use of cement. The number of intraoral procedures required is also reduced. The purpose of this article is to report a case using the Locator F‐Tx Attachment System to facilitate fabrication of an esthetic, clinician‐retrievable, full‐arch implant‐supported fixed dental prosthesis.  相似文献   
75.
76.
AIM: To evaluate the role of magnetic resonance imaging (MRI) for staging local disease and lymph node metastases in papillary carcinoma of the thyroid by comparing MRI with ultrasound (US) of the neck. MATERIALS AND METHODS: Fourteen patients with papillary carcinoma underwent MRI and US. The images were prospectively reviewed for (1) identification of the primary lesion; (2) presence of multifocal thyroid disease; (3) extracapsular extension; (4) invasion into the trachea, oesophagus and major vessels; and (5) presence of lymph node metastases. Correlation was made with the surgical findings. RESULTS: The site of the primary lesion was correctly identified by US in 14 of 14 (100%) and by MRI in 13 of 14 (93%) of patients. Multifocal thyroid tumour was correctly identified by US in two of two patients (100%) and by MRI in zero of two (0%). Extracapsular extension (n = 9), oesophageal invasion (n = 1) and tracheal invasion (n = 2) were identified by MRI in seven, zero, and one, and by US in six, zero and zero patients, respectively. Invasion of the major vessels was not seen. Metastatic cervical nodes were present in 19 nodal groups in 10 patients involving the internal jugular chain (n = 10), posterior triangle (n = 4) supraclavicular fossa (n = 1) and central group (n = 4). Both MRI and US failed to identify metastatic nodes in the central group but correctly identified 14 of the 15 nodal groups outside the central group. CONCLUSION: Ultrasound should be used as the first line of investigation for detecting the primary lesion, multifocal disease and cervical lymphadenopathy. In cases where the primary tumour is not surrounded by normal thyroid tissue MR imaging should be added to assess extracapsular spread, especially into the trachea.  相似文献   
77.
78.
维生素K3粉末降解动力学   总被引:1,自引:0,他引:1  
在温度为50~90℃,相对湿度为50~93%范围内,维生素K3的变色速率方程为—dR/dt=kRR,降解速率方程为d(Co—c)/dt=kC(co—c)1/2,光解速率方程为—dR/dt=kP(Ro—R)-1。kRC与热力学温度T和相对湿度RH的关系通式为k=k′exp(—EA/RT)exp(m′RH)。在实验温度和湿度范围内,变色和降解的表观活化能平均值分别为105.51和130.72 kJ/mol。  相似文献   
79.
80.
BACKGROUND: Brainstem gliomas are highly heterogeneous tumors both in their clinical manifestation and in their pathology. Despite significant advances in the surgery for brainstem gliomas many aspects of this pathology are still unelear. OBJECTIVE: To evaluate the clinical, radiological and surgical outcome of 40 focal "intrinsic" brainstem gliomas and propose a surgical strategyoriented classification. MATERIALS AND METHODS: A total of 40 focal ‘intrinsie’ ("expanding variety") tumors have been operated over a period of 8.5-years (January 1998-June 2007). Our criteria included patients with (1) well-defined gadolinium enhancing tumor, (2) relatively long duration of symptoms (〉 six months) and (3) good neurological functional status and independent for all activities of davy living. The cutoff size of 2 cm was not rigidly adhered to. RESULTS: The "intrinsic" brainstem tumors were classified into three types: Expanding, diffuse infiltrative and pure ventral varieties.  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