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   385篇
  免费   21篇
  国内免费   11篇
耳鼻咽喉   1篇
儿科学   29篇
妇产科学   2篇
基础医学   39篇
口腔科学   2篇
临床医学   36篇
内科学   62篇
皮肤病学   7篇
神经病学   7篇
特种医学   132篇
外科学   22篇
综合类   30篇
预防医学   12篇
眼科学   2篇
药学   16篇
中国医学   3篇
肿瘤学   15篇
  2022年   1篇
  2020年   3篇
  2019年   3篇
  2018年   6篇
  2016年   5篇
  2015年   6篇
  2014年   7篇
  2013年   20篇
  2012年   5篇
  2011年   5篇
  2010年   12篇
  2009年   15篇
  2008年   12篇
  2007年   16篇
  2006年   6篇
  2005年   5篇
  2004年   5篇
  2003年   5篇
  2002年   6篇
  2001年   6篇
  2000年   3篇
  1999年   5篇
  1998年   40篇
  1997年   33篇
  1996年   18篇
  1995年   13篇
  1994年   14篇
  1993年   15篇
  1992年   1篇
  1991年   2篇
  1990年   9篇
  1989年   9篇
  1988年   11篇
  1987年   10篇
  1986年   12篇
  1985年   15篇
  1984年   4篇
  1983年   5篇
  1982年   10篇
  1981年   7篇
  1980年   9篇
  1978年   9篇
  1977年   7篇
  1976年   4篇
  1975年   3篇
排序方式: 共有417条查询结果,搜索用时 15 毫秒
51.
52.
A major problem in the cytogenetic analysis of hematologic neoplasms has been an inability to identify the cell from which the chromosomes were obtained. We describe a procedure that allows simultaneous analysis of karyotype and cell cytology in mitotic cells. The method differs from conventional cytogenetic analysis in that after mild hypotonic treatment, the cells are cytocentrifuged onto glass slides. In mitotic cells, this procedure often results in adequate spread of the chromosomes within the intact cell membrane. The cytoplasmic structure also remains intact, so that cytologic preparations are of good quality. Morphologic and immunologic identification of mitotic cells can be done using routine hematologic stains, such as Giemsa or Sudan black B, and various antisera using immunofluorescence techniques. The chromosomes can be simultaneously analyzed either without banding on slides stained with Giemsa or with Q-banding on slides stained with immunofluorescence techniques. Identification of numerical and structural karyotype aberrations thus is possible in morphologically identified cells.  相似文献   
53.
54.
Rholl  KS; Lee  JK; Ling  D; Sicard  GA; Griffith  RC; Freeman  M 《Radiology》1986,160(1):113-117
Findings of magnetic resonance (MR) imaging in acute renal rejection and acute tubular necrosis (ATN) were studied in dogs. On T1-weighted images, corticomedullary differentiation was absent in kidneys undergoing acute rejection. The loss of corticomedullary differentiation in these kidneys was secondary to a decrease in the relative signal intensity of the cortex, indicating prolongation of the T1 relaxation time of the cortex. In contrast, corticomedullary differentiation was preserved on T1-weighted images of autotransplanted kidneys and kidneys with ATN. MR imaging findings correlated with changes in water content in these three groups of kidneys. Kidneys undergoing acute rejection showed a marked increase in water content compared with kidneys in the other two groups. No change in fat content was found in any group.  相似文献   
55.
56.
57.
58.
To increase transgenic production of granulocyte-macrophage colony- stimulating factor (GM-CSF), we mutated the mRNA's 3'-untranslated region, AUUUA instability elements. Expression vectors containing human or murine GM-CSF cDNAs coding for wild-type (GM-AUUUA) or mutant versions with reiterated AUGUA repeats (GM-AUGUA) were transfected into cells in culture or animals using particle-mediated gene-transfer technology. Normal peripheral blood mononuclear cells accumulated 20- fold greater levels of GM-CSF mRNA and secreted comparably greater amounts of cytokine after transfection with hGM-AUGUA expression vectors versus hGM-AUUUA. hGM-AUGUA mRNA was fivefold more stable (t 1/2 = 95 minutes) than hGM-AUUUA mRNA (t 1/2 = 20 minutes), accounting for elevated steady-state levels. Transfection site extracts and serum samples obtained 24 hours after gene transfer of hGM-AUGUA cDNA into mouse skin contained greater than 32 ng/mL and 650 pg/mL of GM-CSF protein, respectively, compared with 0.33 ng/mL and less than 8 pg/mL for hGM-AUUUA cDNA. GM-CSF produced from mGM-AUGUA cDNA transfected into rat abdominal epidermis induced a profound neutrophil infiltrate. These data suggest a novel strategy for enhanced production of biologically active cytokines by normal cells after in vivo gene transfer.  相似文献   
59.
JK Kruit 《Clinical genetics》2008,73(3):227-228
ATM-dependent suppression of stress signaling reduces vascular disease in metabolic syndrome
Schneider et al. (2006)
Cell Metabolism: 4 (5): 377–389  相似文献   
60.
Riederer  SJ; Brody  WR; Enzmann  DR; Hall  AL; Maier  JK 《Radiology》1983,147(3):859-862
Temporal filtering methods were applied to iodine signal-to-noise ratio (SNR) restoration in intravenous hybrid subtraction digital subtraction angiography (DSA). For equal detected exposure rates hybrid subtraction had approximately 35% of the SNR of temporal subtraction. When matched filtering was applied to a DSA run, the filtered result had approximately two times higher SNR than the peak contrast image in the run. Thus, when matched filtering techniques were applied to the hybrid image sequence, the resultant SNR increased to about 70% of that of temporal subtraction. With an additional factor-of-two increase in exposure rate for the hybrid run, SNR parity with temporal subtraction could be achieved. This compared with a factor-of-nine increase in exposure that would be required if no filtering were performed. Experimental hybrid matched filter results, generated with intravenous canine DSA studies, supported the predictions in SNR performance.  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