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   459篇
  免费   34篇
儿科学   28篇
妇产科学   6篇
基础医学   47篇
口腔科学   14篇
临床医学   65篇
内科学   93篇
皮肤病学   14篇
神经病学   10篇
特种医学   131篇
外科学   14篇
综合类   13篇
预防医学   18篇
眼科学   1篇
药学   18篇
肿瘤学   21篇
  2023年   1篇
  2022年   5篇
  2021年   8篇
  2020年   1篇
  2019年   4篇
  2018年   10篇
  2017年   3篇
  2016年   6篇
  2015年   13篇
  2014年   8篇
  2013年   27篇
  2012年   4篇
  2011年   5篇
  2010年   23篇
  2009年   26篇
  2008年   3篇
  2007年   5篇
  2006年   6篇
  2005年   4篇
  2004年   6篇
  2003年   3篇
  2002年   2篇
  2001年   5篇
  2000年   2篇
  1999年   7篇
  1998年   28篇
  1997年   29篇
  1996年   32篇
  1995年   24篇
  1994年   25篇
  1993年   21篇
  1992年   3篇
  1991年   6篇
  1990年   3篇
  1989年   16篇
  1988年   12篇
  1987年   12篇
  1986年   9篇
  1985年   9篇
  1984年   6篇
  1983年   6篇
  1982年   8篇
  1981年   9篇
  1980年   3篇
  1979年   5篇
  1978年   7篇
  1977年   13篇
  1976年   8篇
  1975年   10篇
  1968年   2篇
排序方式: 共有493条查询结果,搜索用时 15 毫秒
91.
92.

Background  

Glioblastoma is one of the deadliest forms of cancer, in part because of its highly invasive nature. The tumor suppressor PTEN is frequently mutated in glioblastoma and is known to contribute to the invasive phenotype. However the downstream events that promote invasion are not fully understood. PTEN loss leads to activation of the atypical protein kinase C, PKCι. We have previously shown that PKCι is required for glioblastoma cell invasion, primarily by enhancing cell motility. Here we have used time-lapse videomicroscopy to more precisely define the role of PKCι in glioblastoma.  相似文献   
93.
94.
Osteoprotegerin (OPG) is a member of the tumor necrosis factor receptor superfamily of proteins. Although initial data illustrated the key role that OPG plays in bone turnover, numerous recent reports indicate that OPG is also an important factor in inflammatory pathways and tumor cell survival. OPG contributes directly to inflammatory processes and has been evaluated as a novel non‐invasive biomarker of gut inflammation. Furthermore, OPG affects cell turn‐over, differentiation, death, and survival via extracellular pathways, correlating with worse prognosis in inflammatory bowel diseases and several gastrointestinal carcinomas. It is now clear that OPG has multiple functions and characteristics. This review gives an overview of OPG, highlights its roles in different extracellular pathways, and outlines how OPG could be used as a novel non‐invasive biological marker in inflammatory bowel diseases and gastrointestinal carcinomas.  相似文献   
95.
96.
97.
98.
Morrison  AE; Ludlam  CA; Kessler  C 《Blood》1993,81(6):1513-1520
Data have been collected from 47 centers in Europe and North America on the treatment with porcine factor VIII concentrate of 74 acute bleeding episodes in 65 patients with acquired hemophilia. The median initial anti-human factor VIII auto-antibody inhibitor level was 38 Bethesda unit (BU)/mL (range 1.2 to 1,024) whereas that against porcine was 1 BU/mL (range 0 to 15). The mean initial dose of porcine factor VIII infused was 84 IU/kg, which increased the plasma factor VIII:C activity by 0.85 IU/mL. Therapy was continued for a mean of 8.5 days during which time the average number of infusions was 11. Objective clinical responses were rated as good or excellent in 78% of recipients. Side effects were uncommon; only one patient experienced a severe anaphylactic reaction necessitating the discontinuation of porcine FVIII therapy. After therapy, no increase in the median level of anti- human FVIII or anti-porcine antibody was noted in the group as a whole, although 13 patients showed individual increases in either anti-human or anti-porcine antibody levels or both of more than 10 BU/mL. Of the 7 patients who subsequently rebled, 5 were successfully re-treated and 2 did not respond to further porcine factor VIII treatment. Porcine factor VIII is safe and clinically effective treatment for bleeding episodes associated with acquired hemophilia and should be considered as first-line therapy for patients whose acquired anti-factor VIII:C antibody cross-reacts with porcine factor VIII:C at low levels.  相似文献   
99.
ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tcr) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).ResultsPCR analysis indicated that Tcr E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.  相似文献   
100.
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