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   3390篇
  免费   195篇
  国内免费   14篇
耳鼻咽喉   36篇
儿科学   88篇
妇产科学   54篇
基础医学   459篇
口腔科学   33篇
临床医学   263篇
内科学   758篇
皮肤病学   72篇
神经病学   305篇
特种医学   66篇
外科学   594篇
综合类   16篇
预防医学   119篇
眼科学   28篇
药学   317篇
中国医学   5篇
肿瘤学   386篇
  2023年   39篇
  2022年   53篇
  2021年   83篇
  2020年   44篇
  2019年   65篇
  2018年   75篇
  2017年   62篇
  2016年   79篇
  2015年   81篇
  2014年   114篇
  2013年   145篇
  2012年   220篇
  2011年   254篇
  2010年   138篇
  2009年   105篇
  2008年   197篇
  2007年   209篇
  2006年   179篇
  2005年   188篇
  2004年   170篇
  2003年   143篇
  2002年   143篇
  2001年   66篇
  2000年   57篇
  1999年   50篇
  1998年   26篇
  1997年   19篇
  1996年   19篇
  1995年   10篇
  1994年   14篇
  1993年   21篇
  1992年   40篇
  1991年   53篇
  1990年   48篇
  1989年   41篇
  1988年   43篇
  1987年   45篇
  1986年   33篇
  1985年   33篇
  1984年   34篇
  1983年   25篇
  1982年   10篇
  1981年   9篇
  1980年   9篇
  1979年   24篇
  1978年   16篇
  1977年   9篇
  1976年   11篇
  1975年   9篇
  1969年   7篇
排序方式: 共有3599条查询结果,搜索用时 15 毫秒
61.
Abstract A 53-year-old Japanese female, who had been suffering from idiopathic pulmonary fibrosis (IPF) for 3 years, was admitted with dyspnoea. The important laboratory finding on admission was a serum CA19-9 level of 649 U/mL. Despite steroid treatment for IPF, her respiratory condition gradually deteriorated with the increase of serum CA19-9 level up to 3020 U/mL and she died of respiratory failure. Immunohistochemistry showed the positive stain of CA19-9 in bronchoepithelial cells. We also reviewed the Index Medics and picked up the cases who had elevation of CA19-9 more than 1000 U/mL, and six patients were listed. Five of these six patients died within 6 months, therefore the marked elevation of CA19-9 seemed to be a bad prognostic factor in patients with pulmonary fibrosis.  相似文献   
62.
Hyperuricemia and oxidative stress participate in the pathophysiology of hypertension and its complications. Xanthine dehydrogenase (XDH) produces urate and, in its oxidase isoform, reactive oxygen species. Here we have studied whether or not the genetic variations in XDH could be implicated in hypertension and its complications. By sequencing the promoter region and all exons of XDH in 48 subjects, we identified three missense mutations (G172R, A932T, N1109T) in a heterozygous state in addition to 34 variations, including 15 common single nucleotide polymorphisms (SNPs). The three missense mutations and eight common SNPs (11488C>G, 37387A>G, 44408A>G, 46774G>A, 47686C>T, 49245A>T, 66292C>G, and 69901A>C) were genotyped in 953 hypertensive Japanese subjects and in 1,818 subjects from a general Japanese population. Four hypertensive patients with rare missense mutations (G172R or N1109T) in homozygous form had severe hypertension. Multivariate logistic regression analysis showed a significant association of three SNPs with hypertension in men: 47686C>T (exon 22, odds ratio [OR]: 1.52, p = 0.047) and 69901A>C (intron 31, OR: 3.14, p = 0.039) in the recessive model, and 67873A>C (N1109T) (exon 31, OR: 1.84, p = 0.018) in the dominant model. After full adjustment for all confounding factors, only one polymorphism (69901A>C) was found to be associated with carotid atherosclerosis in the dominant model (p = 0.028). Multiple logistic regression analysis showed that one SNP (66292C>G) was significantly associated with chronic kidney disease (CKD: estimated creatinine clearance < 60 ml/min) in the recessive model (p = 0.0006). Our results suggest that genetic variations in XDH contribute partly to hypertension and its complications, including atherosclerosis and CKD.  相似文献   
63.
Portal vein thrombosis is a rare surgical complication following liver transplantation, which remains a cause of graft loss and death. We describe here the treatment of portal vein thrombosis following living donor liver transplantation using an extended left lobe graft. The patient was treated with a Gore-Tex vascular jump graft extra-anatomically interposed between the recipient superior mesenteric vein and the donor umbilical vein. This technique allowed the hepatic hilum to be left untouched and supplied suitable blood flow to the hepatic allograft. Our experience suggests that this innovative technical solution can be helpful in the effort to rescue cases of hepatic allograft with vascular complications.  相似文献   
64.
The spontaneous rupture of a primary hepatocellular carcinoma (HCC) accounts for 10% mortality of HCC patients in Japan. Because this problem occurs much less frequently in western countries, it is often difficult for clinicians practicing in such countries to decide upon the best course of action during the crisis accompanying the spontaneous rupture of a HCC. In an effort to advance the general knowledge of this disease and clarify a selection for its treatment, we review 172 cases of spontaneous rupture of a HCC reported in the Japanese literature. The chief complaint of the patients was sudden epigastralgia or right hypochondriac pain. Abdominal paracentesis was positive in 86% of the patients. Liver failure was the cause of death in 42% of the patients. Therefore, it is important to evaluate liver reserve quickly. In addition, emergency hemostatic procedures must be implemented to avoid hemorrhagic shock. Although two-stage hepatectomy was performed in only 12% of the cases, these had the highest survival rates. Consequently, this is the procedure of choice for the treatment of spontaneous rupture of a HCC.  相似文献   
65.
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   
66.
67.
The Notch signaling pathway plays a key role in the morphogenesis of the biliary tree, but its involvement in cystic biliary diseases, such as Caroli disease (CD) and polycystic liver disease (PLD), has yet to be determined. Immunostaining was performed using liver sections of CD and PLD, and the results were compared with those of congenital hepatic fibrosis (CHF) and von Meyenburg complex (VMC). The expression of Notch receptor 1 (Notch1) was increased in the nuclei of biliary epithelial cells in all cases of CD and PLD, whereas it remained at a low level in CHF and VMC. In addition, Notch2 and Notch3 were preferably expressed in the nuclei of biliary epithelial cells of PLD. Accordingly, the Notch effector Hes1 was highly expressed in biliary epithelial cells of CD and PLD, and the cell proliferative activity was significantly higher in CD and PLD. The expression of the Notch ligand Delta-like 1 was significantly increased in biliary epithelial cells of CD and PLD, which may be causally associated with the nuclear overexpression of Notch1 and Hes1. These results indicate that aberrant activation of the Notch-Hes1 signaling pathway may be responsible for the progression of biliary cystogenesis in CD and PLD.  相似文献   
68.
Objective:To compare positive predictive values (PPVs) of clumped vs non-clumped (homogenous and heterogeneous) internal enhancement on MRI detected linear non-mass enhancement (NME) on MRI-guided vacuum-assisted breast biopsy (MRI-VABB).Methods:With IRB (Institutional Review Board) approval, we retrospectively reviewed 598 lesions undergoing MRI-VABB from January 2015 to April 2018 that showed linear NME. We reviewed the electronic medical records for MRI-VABB pathology, any subsequent surgery and clinical follow-up. The X2 test was performed for univariate analysis.Results:There were 120/598 (20%) linear NME MRI-VABB lesions with clumped (52/120, 43%) vs non-clumped (68/120, 57%) internal enhancement, average size 1.8 cm (range 0.6–7.6 cm). On MRI-VABB, cancer was identified in 22/120 (18%) lesions, ductal carcinoma in situ (DCIS) was found in 18/22 (82%) and invasive cancer in 4 (18%). 3/31 (10%) high-risk lesions upgraded to DCIS at surgery, for a total of 25/120 (21%) malignancies. Malignancy was found in 12/52 (23%) clumped lesions and in 13/68 (19%) of non-clumped lesions that showed heterogeneous (5/13, 38%) or homogenous (8/13, 62%) internal enhancement. The PPV of linear NME with clumped internal enhancement (23.1%) was not significantly different from the PPV of non-clumped linear NME (19.1%) (p = 0.597). The PPV of linear NME lesions <1 cm (33.3%) was not significantly different from the PPV of lesions ≥1 cm (18.6%) (p = 0.157).Conclusions:Linear NME showed malignancy in 21% of our series. Linear NME with clumped or non-clumped internal enhancement patterns, regardless of lesion size, might need to undergo MRI-VABB in appropriate populations.Advances in knowledge:Evaluation of linear NME lesions on breast MRI focuses especially on internal enhancement pattern.  相似文献   
69.
70.
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