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   45647篇
  免费   2319篇
  国内免费   211篇
耳鼻咽喉   347篇
儿科学   919篇
妇产科学   698篇
基础医学   5892篇
口腔科学   1121篇
临床医学   3068篇
内科学   11286篇
皮肤病学   846篇
神经病学   3365篇
特种医学   1606篇
外科学   8050篇
综合类   213篇
一般理论   1篇
预防医学   1635篇
眼科学   613篇
药学   3342篇
中国医学   143篇
肿瘤学   5032篇
  2023年   260篇
  2022年   481篇
  2021年   887篇
  2020年   525篇
  2019年   696篇
  2018年   898篇
  2017年   699篇
  2016年   826篇
  2015年   907篇
  2014年   1188篇
  2013年   1393篇
  2012年   2152篇
  2011年   2294篇
  2010年   1283篇
  2009年   1064篇
  2008年   2030篇
  2007年   2158篇
  2006年   2029篇
  2005年   2092篇
  2004年   2134篇
  2003年   2006篇
  2002年   2028篇
  2001年   1717篇
  2000年   1661篇
  1999年   1586篇
  1998年   614篇
  1997年   494篇
  1996年   443篇
  1995年   364篇
  1994年   363篇
  1993年   323篇
  1992年   1014篇
  1991年   946篇
  1990年   830篇
  1989年   910篇
  1988年   782篇
  1987年   712篇
  1986年   751篇
  1985年   681篇
  1984年   440篇
  1983年   378篇
  1982年   195篇
  1981年   191篇
  1979年   314篇
  1978年   240篇
  1977年   210篇
  1975年   210篇
  1974年   185篇
  1973年   173篇
  1971年   176篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
We have applied DNA flow cytometric analysis to paraffin-embedded tissue sections of primary malignant melanomas. Conventionally, flow cytometric analysis of paraffin-embedded tissue sections has been done by the method of Hedley et al. We added ultrasound treatment to the method of Hedley et al. and a lower value of coefficient of variation was shown. Furthermore, a new technique, fluorescence in situ hybridization with a chromosome-specific repetitive DNA probe, was used for the analysis of chromosomal numerical aberrations in the same paraffin-embedded tissue sections. The DNA flow cytometric analysis showed that in 8 cases six primary malignant melanomas were of the aneuploid pattern and two cases of lentigo maligna (melamona in situ) were of the diploid pattern. By fluorescence in situ hybridization, the two cases with the diploid pattern had spots/nucleus of 1.28 and 1.12, and those with the aneuploid pattern had spots/nucleus from 2.01 to 2.27. Only one nodular melanoma in an aneuploid case showed spots/nucleus of 1.71. These data indicate that fluorescence in situ hybridization with chromosome-specific repetitive DNA probes can serve as a cytogenetic tool for the analysis of interphase nuclei of solid human tumors and may be useful for the study of tumor cell heterogeneity.  相似文献   
93.
94.
A 60-year-old man suffered from paraplegia after the operation for thoracic aortic aneurysm and died 10 months after the operation. Detailed examination on the distribution of spinal cord lesions and of the locations of anterior radicular arteries revealed that the spinal cord ischemia occurred at the mid-thoracic segments between T-6 and T-10; the artery of Adamkiewicz entered at T-12; another radicular artery entered at T-4. We concluded that the spinal cord ischemia was caused by the interruption of the radicular artery at T-4 and that the segments nourished by the blood flow of the artery of Adamkiewicz were intact. We suggest that in some patients important radicular arteries other than the artery of Adamkiewicz are essential to preserve blood flow to the upper or middle thoracic spinal segments.  相似文献   
95.
96.
97.
98.
A 72-year-old man with recurrent pancreatitis and a horseshoe-shaped anomaly of the pancreas is described. The diagnosis was made by endoscopic retrograde cholangiopancreatography (ERCP) and computed tomography scan; laparotomy was confirmatory. The abnormal duct branched to the lower left from an enlarged Santorini's duct; a thin Wirsung's duct was joined at its distal portion to the junction of the abnormal duct. The anomaly was associated with a cystic dilatation of the common bile duct with stone and cholecystolithiasis. This anomaly is considered to be a variation of the dominant dorsal duct syndrome.  相似文献   
99.
Superior cervical ganglionectomy (SCGx) abolished the nocturnal rise in pineal type-II thyroxine 5'-deiodinase (5'-D) activity in both euthyroid and hypothyroid rats. Isoproterenol induced at least as great a rise in diurnal pineal 5'-D in SCGx as in intact rats. These data suggest that beta-adrenergic stimulation through the superior cervical ganglia is essential for the nocturnal rise in pineal 5'-D activity.  相似文献   
100.
Monoclonal antibodies to human hemoglobin were produced and a colloidal gold agglutination method has been developed for detection of fecal occult blood. Since hemoglobin is composed of the tetramer, alpha 2 beta 2, a single monoclonal antibody-labeled colloidal gold can agglutinate with hemoglobin. The lowest detectable hemoglobin concentration was 0.5 micrograms/ml. A total of 785 fecal samples were determined using colloidal gold agglutination and compared with latex agglutination. The colloidal gold agglutination detected blood in 75 samples, whereas latex agglutination detected blood in 76 samples, and among them 70 were positive in both methods. Overall agreement between the two methods was 98%.  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