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   3940篇
  免费   189篇
  国内免费   32篇
耳鼻咽喉   25篇
儿科学   70篇
妇产科学   69篇
基础医学   487篇
口腔科学   121篇
临床医学   260篇
内科学   1297篇
皮肤病学   111篇
神经病学   186篇
特种医学   98篇
外科学   574篇
综合类   24篇
预防医学   108篇
眼科学   15篇
药学   236篇
中国医学   5篇
肿瘤学   475篇
  2023年   55篇
  2022年   117篇
  2021年   143篇
  2020年   63篇
  2019年   76篇
  2018年   107篇
  2017年   78篇
  2016年   92篇
  2015年   94篇
  2014年   110篇
  2013年   162篇
  2012年   288篇
  2011年   293篇
  2010年   155篇
  2009年   134篇
  2008年   239篇
  2007年   232篇
  2006年   234篇
  2005年   241篇
  2004年   201篇
  2003年   200篇
  2002年   231篇
  2001年   44篇
  2000年   40篇
  1999年   50篇
  1998年   49篇
  1997年   48篇
  1996年   31篇
  1995年   31篇
  1994年   19篇
  1993年   19篇
  1992年   24篇
  1991年   17篇
  1990年   11篇
  1989年   13篇
  1988年   22篇
  1987年   22篇
  1986年   14篇
  1985年   14篇
  1984年   11篇
  1983年   13篇
  1982年   7篇
  1981年   8篇
  1980年   7篇
  1973年   7篇
  1972年   9篇
  1970年   6篇
  1969年   14篇
  1968年   8篇
  1967年   10篇
排序方式: 共有4161条查询结果,搜索用时 15 毫秒
61.
A rare case of systemic vasculitis with second component of complement (C2) deficiency was documented in a patient who developed colonic ulcerations, jejunal edema and dilatation, cutaneous ulcers, peripheral neuropathy, and psychosis. Colonoscopy revealed typical features of ischemic colitis and radiological examination showed ischemic changes in the jejunum and ileum. Histopathological examination of the cutaneous biopsy revealed typical necrotizing vasculitis. It is very likely that multiorgan involvement, including ischemic changes of the intestine, developed secondary to vasculitis associated with C2 deficiency.  相似文献   
62.
63.
The potent and selective phosphodiesterase 4 inhibitor ASP3258 is a novel therapeutic agent for asthma and chronic obstructive pulmonary disease (COPD). After a single oral administration to rats, ASP3258 is rapidly absorbed with a bioavailability of 106%. In situ absorption data indicated that ASP3258 is mainly absorbed in the small intestine. Tissue distribution data after oral administration of 14C‐ASP3258 showed rapid and extensive distribution to various tissues. Excluding the gastrointestinal tract, the tissues with the highest concentrations were liver, heart and plasma. Liquid chromatography‐nuclear magnetic resonance spectroscopy data revealed that O‐glucuronidation of the carboxylic acid moiety of ASP3258 (formation of an acyl glucuronide) plays a key role in metabolism. No indication was found that the acyl glucuronide reacted with proteins in plasma or tissues. When 14C‐ASP3258 was orally administered to intact rats, urinary and fecal excretion accounted for 1.3% and 100.6% of the administered radioactivity, respectively. After a single oral administration of 14C‐ASP3258 to bile‐cannulated rats, urinary and biliary excretion accounted for 0.7% and 93.8% of the administered radioactivity, respectively. These findings suggest that fecal excretion via bile plays an important role in the elimination of ASP3258‐derived radioactivity. In vitro metabolic profiles were relatively similar among the species examined, suggesting that our findings in rats may help us to understand pharmacokinetics, efficacy and safety profiles in humans and other species. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
64.
Journal of Gastroenterology - Following liver transplantation (LT), allograft liver failure can be developed by various causes and requires re-LT. Hence, this study aimed to clarify the...  相似文献   
65.
66.
The human liver contains significant numbers of innate immune cells, such as natural killer (NK) cells and natural killer T (NKT) cells, which express both T-cell receptors and NK-cell receptors simultaneously. It has been suggested that the innate immune system plays a crucial role in the liver. In this report, the distribution of NK and NKT cells in the liver and peripheral blood of two patients with drug-induced fulminant hepatic failure (FHF) who had undergone living donor liver transplantation was examined. In both the liver and peripheral blood, the proportions of NK and NKT cells markedly decreased compared with those in healthy donors. It was also revealed that, unlike murine NKT cells, human CD56(+) T cells and CD57(+) T cells did not constitutively express CD28, which is one of the important costimulatory molecules on T cells. Additionally, the residual CD56(+) T cells and CD57(+) T cells in the patients expressed more CD28 than in controls. This result suggests that NKT cells might be more activated in FHF. Although the accumulation of further cases is required, it is suggested that both NK and NKT cells might be involved in hepatic injury in FHF.  相似文献   
67.
68.
69.
Background/Aims: Identification of the risk factors of multicentric hepatocarcinogenesis is important for the clinical management of hepatocellular carcinoma. We investigated hyperplastic foci in non-cancerous liver parenchyma, and clarified their pathological features and clinical significance.Methods: Hyperplastic foci were defined as hypercellular areas, which architecturally and cytologically resembled early hepatocellular carcinoma or adenomatous hyperplasia but did not form macroscopically detectable nodules. Surgically resected livers from 155 patients with hepatocellular carcinoma were examined histopathologically and immunohistochemically.Results: Hyperplastic foci were found in 26 of 155 patients (16.8%). All the patients with hyperplastic foci had chronic liver diseases, and the incidence did not differ between those with chronic hepatitis and those with liver cirrhosis. Six of 92 (6.5%) patients with single primary hepatocellular carcinoma nodules, 8 of 42 (19.0%) with two nodules, and 12 of 21 (57.0%) with more than three nodules had hyperplastic foci. The incidence of hyperplastic foci showed a significant positive correlation with the multiplicity of hepatocellular carcinoma nodules. Immunohistochemically, hyperplastic foci were masses of proliferative hepatocytes similar to adenomatous hyperplasia and early hepatocellular carcinoma.Conclusions: Hyperplastic foci reflect the risk of multicentric hepatocarcinogenesis. Our results suggest strongly that hyperplastic foci are precursors of adenomatous hyperplasia or hepatocellular carcinoma.  相似文献   
70.
The cell-cycle status of hematopoietic stem and progenitor cells (HSPCs) becomes activated following chemotherapy-induced stress, promoting bone marrow (BM) regeneration; however, the underlying molecular mechanism remains elusive. Here we show that BM-resident group 2 innate lymphoid cells (ILC2s) support the recovery of HSPCs from 5-fluorouracil (5-FU)–induced stress by secreting granulocyte-macrophage colony-stimulating factor (GM-CSF). Mechanistically, IL-33 released from chemo-sensitive B cell progenitors activates MyD88-mediated secretion of GM-CSF in ILC2, suggesting the existence of a B cell–ILC2 axis for maintaining hematopoietic homeostasis. GM-CSF knockout mice treated with 5-FU showed severe loss of myeloid lineage cells, causing lethality, which was rescued by transferring BM ILC2s from wild-type mice. Further, the adoptive transfer of ILC2s to 5-FU–treated mice accelerates hematopoietic recovery, while the reduction of ILC2s results in the opposite effect. Thus, ILC2s may function by “sensing” the damaged BM spaces and subsequently support hematopoietic recovery under stress conditions.  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