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   431篇
  免费   6篇
  国内免费   22篇
耳鼻咽喉   1篇
儿科学   6篇
妇产科学   11篇
基础医学   161篇
口腔科学   1篇
临床医学   25篇
内科学   83篇
皮肤病学   7篇
神经病学   14篇
特种医学   1篇
外科学   37篇
综合类   5篇
预防医学   2篇
眼科学   2篇
药学   46篇
肿瘤学   57篇
  2021年   3篇
  2018年   3篇
  2016年   2篇
  2015年   3篇
  2014年   3篇
  2013年   6篇
  2012年   7篇
  2011年   7篇
  2010年   16篇
  2009年   14篇
  2008年   19篇
  2007年   31篇
  2006年   17篇
  2005年   16篇
  2004年   13篇
  2003年   16篇
  2002年   13篇
  2001年   24篇
  2000年   17篇
  1999年   15篇
  1998年   9篇
  1997年   15篇
  1996年   13篇
  1995年   11篇
  1994年   3篇
  1993年   3篇
  1992年   10篇
  1991年   14篇
  1990年   11篇
  1989年   16篇
  1988年   15篇
  1987年   7篇
  1986年   12篇
  1985年   9篇
  1984年   10篇
  1983年   11篇
  1982年   4篇
  1981年   2篇
  1980年   2篇
  1979年   9篇
  1978年   7篇
  1977年   5篇
  1973年   1篇
  1972年   3篇
  1971年   3篇
  1970年   1篇
  1969年   2篇
  1967年   3篇
  1966年   1篇
  1954年   1篇
排序方式: 共有459条查询结果,搜索用时 249 毫秒
101.
Material and methods We analyzed the expression of hypoxia inducible factor-1α (HIF-1α) and glucose transporter-1 (GLUT-1) by immunohistochemistry in ovarian serous and mucinous tumors from the point view of the histological characteristics and acquisition of malignancy. A total of 102 ovarian tumors were examined, composed of 31 adenomas (serous 17 and mucinous 14), 32 borderline tumors (serous 13 and mucinous 19), and 39 adenocarcinomas (serous 21 and mucinous 18). Results The overall positive ratios were as follows: HIF-1α, 74% of adenomas, 91% of borderline tumors, and 100% of adenocarcinomas; and GLUT-1, 68% of adenomas, 95% of borderline tumors, and 100% of adenocarcinomas. Comparing serous tumors and mucinous tumors, there was no significant difference in the positive ratios of HIF-1α and GLUT-1 of adenomas, borderline tumors, and adenocarcinomas. However, both markers were more strongly expressed in serous adenocarcinomas (HIF-1α, 3 + 100%; GLUT-1, 3 + 76%) than in mucinous adenocarcinomas (HIF-1α, 3 + 61%; GLUT-1, 3 + 28%). The results of immunoblotting and mRNA expression level analyses corresponded with those of immunohistochemical expression profiles. DNA binding assay also demonstrated that HIF-1 is more commonly activated in serous adenocarcinomas than in mucinous adenocarcinomas. Conclusion HIF-1α and GLUT-1 expressions seemed to be coordinated to adapt ovarian tumor cells into hypoxic conditions in close association with the acquisition of malignancy. We consider that the relatively strong expression of both markers in serous tumors compared with mucinous tumors is related to the difference in their histological characteristics.  相似文献   
102.
白首乌化学成分的研究   总被引:4,自引:0,他引:4  
自白首乌主要品种耳叶牛皮消(Cynanchum auriculatum Royle ex Wight)根中首次分得三个已知甾体酯型甙元:告达亭(caudatin),开德甙元(kidjolanin),萝藦甙元(Metaplexigenin)和一种新的二苯酮衍生物(Ⅳ),经光谱分析推定其结构为2,6,2′,5′-四羟基,3-乙酰基,6′-甲基二苯酮,命名白首乌二苯酮。  相似文献   
103.
白首乌化学成分的研究   总被引:11,自引:0,他引:11  
自白首乌主要品种耳叶牛皮消(Cynanchum auriculatum Royle ex Wight)根中首次分得三个已知甾体酯型甙元:告达亭(caudatin),开德甙元(kidjolanin),萝藦甙元(Metaplexigenin)和一种新的二苯酮衍生物(Ⅳ),经光谱分析推定其结构为2,6,2′,5′-四羟基,3-乙酰基,6′-甲基二苯酮,命名白首乌二苯酮。  相似文献   
104.
105.
We hereby report light and electron-microscopic (EM) studies on an unusual case of molluscum contagiosum occurring in an epidermal cyst. It was considered that the pre-existing cyst was inoculated with molluscum contagiosum viruses, which were confirmed electron-microscopically. We also would like to re-emphasize the usefulness of formalin fixed tissue for EM confirmation of viruses.  相似文献   
106.
107.
Expression of Chromogranin A and C was examined immunohistochemically on 45 surgically obtained pituitary adenomas. Positive rate of chromogranin A was 40.0% and chromogranin C was positive in 8.0% of 45 pituitary adenomas. Chromogranin A was expressed frequently in adenomas in which at least one of the FSH alpha, FSH beta, LH beta and TSH beta subunits was positive. It also expressed frequently in non-functioning adenomas. The positive rate of chromogranin A was low in GH or PRL positive adenomas. These findings suggest that chromogranin could be a parameter of the functional differentiation of the pituitary adenomas.  相似文献   
108.
去甲二氢愈创木酸的全合成   总被引:3,自引:0,他引:3  
以香草醛为原料,经甲醚化,氧化和Claisen缩合,合成了相应的β 酮酸酯,再经改进的Knor反应,实现β-酮酸酯的偶联,通过环化、选择性氢化还原等反应,成功地合成了去甲二氢愈创木酸(nordihydroguaiaretic acid);呋喃愈创木酚二甲醚(furoguaiacin dimethyl ether)和二氢愈创木酸二甲醚(dihydroguaiaretic acid dimethyl ether)。  相似文献   
109.
Mitochondrial alterations in aged rat adrenal cortical cells   总被引:1,自引:0,他引:1  
Mitochondrial alteration in aged rat adrenal cortical cells were studied. Severe mitochondrial alterations were predominantly observed in the zonae fasciculata and reticularis of the adrenal cortex. Many adrenal cortical mitochondria from these zones were relatively larger in size and more irregular in shape. The matrix of altered mitochondria appeared denser than normal and the intramitochondrial cristae including myelin-like membrane configurations and parallel arrays were seen. Intramitochondrial inclusions such as paracrystalloid structures were also noted. In addition, giant mitochondria with various inclusions such as highly electron dense lipid-like materials, large vacuoles and other cytoplasmic organelles including small mitochondria were characteristically observed. Based on these data, functional aspects of the altered mitochondria in aged rat adrenal cortical cells were discussed.  相似文献   
110.
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