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   5640篇
  免费   417篇
  国内免费   31篇
耳鼻咽喉   41篇
儿科学   162篇
妇产科学   133篇
基础医学   831篇
口腔科学   177篇
临床医学   420篇
内科学   1327篇
皮肤病学   135篇
神经病学   749篇
特种医学   134篇
外国民族医学   1篇
外科学   516篇
综合类   7篇
一般理论   1篇
预防医学   415篇
眼科学   61篇
药学   408篇
中国医学   15篇
肿瘤学   555篇
  2024年   10篇
  2023年   54篇
  2022年   167篇
  2021年   259篇
  2020年   151篇
  2019年   223篇
  2018年   236篇
  2017年   147篇
  2016年   207篇
  2015年   226篇
  2014年   274篇
  2013年   335篇
  2012年   524篇
  2011年   480篇
  2010年   268篇
  2009年   217篇
  2008年   328篇
  2007年   327篇
  2006年   351篇
  2005年   252篇
  2004年   269篇
  2003年   226篇
  2002年   193篇
  2001年   33篇
  2000年   25篇
  1999年   46篇
  1998年   42篇
  1997年   25篇
  1996年   25篇
  1995年   22篇
  1994年   25篇
  1993年   20篇
  1992年   18篇
  1991年   12篇
  1990年   10篇
  1989年   2篇
  1988年   7篇
  1987年   3篇
  1986年   5篇
  1985年   7篇
  1984年   11篇
  1981年   4篇
  1980年   3篇
  1979年   3篇
  1977年   2篇
  1969年   2篇
  1965年   1篇
  1943年   1篇
  1933年   2篇
  1921年   1篇
排序方式: 共有6088条查询结果,搜索用时 203 毫秒
91.
92.
93.
94.
A 67-year-old woman, who had symptoms of epigastric pain and abdominal distension, was found, on endoscopy, to have a large sessile villous adenoma of the periampullary duodenum. Despite the lack of evidence of malignancy, a pancreaticoduodenectomy procedure was performed, mainly because of the tumor size and site, involving the ampulla of Vater. The presence of the carcinoma was diagnosed only in the resected specimen by definitive histology. Because there is no general consensus on the optimal surgical procedure for the treatment of villous tumors of the duodenum, especially for the early stages, the indications for the operative procedure are discussed, based on a review of the literature.  相似文献   
95.
BACKGROUND: Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. METHODS: A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. RESULTS: Of the 185 symptomatic patients >14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/or thrombocytopenia [platelet count, < or =50,000 platelets/mm3]) and DHF, respectively. The onset of intermediate DF/DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a >3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/DHF. CONCLUSIONS: Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype.  相似文献   
96.
Cytomegalovirus (CMV) disease remains a severe complication in patients who have undergone transplantation. Viremia can be prevented and treated by the adoptive transfer of donor-derived CMV-directed T cells. To ensure long-term protection against CMV disease, it is important to transfer CMV antigen-specific T cells that represent both the CD8+ and the CD4+ subsets. In the present study, we used as stimulators dendritic cells (DCs) that were electroporated with in vitro-transcribed 5'-capped polyadenylated messenger RNA (mRNA) that encoded the CMV pp65 protein (i.e., pp65 mRNA). These DCs could efficiently activate CMV-directed CD8+ T cells, as assayed by tetramer staining, interferon- gamma production, and cytolytic activity. We also used DCs that were pulsed with a recombinant pp65 protein to activate CMV-directed CD4+ T cells. When DCs were comodified with pp65 mRNA and pp65 protein, large numbers of CMV-directed CD8+ and CD4+ T cells were generated simultaneously. The approach outlined in the present study can be adapted for a clinical protocol that circumvents potential virus-related biohazards and is available to all patients independently of their human leukocyte antigen haplotype.  相似文献   
97.
Non-myeloablative stem cell transplantation (NMT) has been increasingly used in compromised patients who would otherwise have been unable to undergo allotransplant. There is little understanding of the kinetics of immune reconstitution and its influence on infective complications following NMT. The aim of present study was to evaluate lymphocyte subset reconstitution over the first 12 months post-transplant in 15 adult patients receiving NMT with comparison to that of 30 patients grafted with a conventional hemopoietic stem cell transplantation (HSCT). NMT recipients were conditioned with fludarabine-based conditioning regimens. Peripheral blood stem cell (PBSC) was the source of stem cells in 13 NMT recipients and in 24 conventional HSCT recipients. Absolute numbers of helper (CD4+) T cells, naive (CD4+ CD45RA+) and memory (CD4+ CD45RO+) T cells as well as suppressor (CD8+) T cells, CD19+ B cells and NK cells were comparable in the two groups at all time points after transplantation. A median value of 200 CD4+ T cells/microl was achieved at 2 months post-transplant by the NMT and HSCT recipients. The CD4:CD8 ratio remained severely depressed throughout the study period. Almost all CD4+ lymphocytes expressed CD45RO antigen in the both groups of patients B lymphocytes showed low counts throughout the entire study period in both groups. Bacteremia and CMV antigenemia occurred respectively in 13 and 36% of the patients in the NMT group and in 15 and 39% of the patients in the HSCT group. Our preliminary data indicate that patients receiving a NMT have a lymphocyte reconstitution similar to that observed in patients who received a conventional HSCT. The incidence of bacteremia and CMV infection were not significantly different between the groups. Nevertheless, due to the small sample size, these results should be considered suggestive rather than definitive.  相似文献   
98.
99.
Digestive Diseases and Sciences - Deregulation of immune response and oxidative stress contribute to nonalcoholic fatty liver disease (NAFLD) pathogenesis. Resistin is a physiological modulator of...  相似文献   
100.
Although surgery alone represents a curative approach for patients with pT3N0M0 colon cancer, about 15–20 % of these patients develop a relapse of disease. Microsatellite instability (MSI) is one of the most important molecular markers in colorectal cancer. The aim of this study was to investigate the prognostic relevance of MSI in all pT3N0M0 tumors recorded in the Cancer Registry of the Province of Modena—(Northern Italy) within the 2002–2006 period in patients who showed a relapse of disease during the 5-year period of follow-up (59 cases). They were compared to 59 controls similar in clinical and pathological features but with good prognosis. None of the subjects received adjuvant chemotherapy. MSI status was tested using BAT25, BAT26, NR24, and CAT25 fluorescent-labeled mononucleotide markers. The overall prevalence of MSI was 12.7 % (15 of 118 cases). MSI was detected mainly in mucinous adenocarcinoma (p < 0.003), in high-grade tumors (p < 0.008), in right-sided neoplasms (p < 0.005), and in patients with a better prognosis, though the difference was not statistically significant (11/59 patients ?18.6 % vs 4/59 patients ?6.7 %; OR 0.36 CI 95 % 0.11–1.15; p = 0.08). However, in multivariate analysis, MSI status becomes the strongest independent factor associated with relapse (OR 0.21, CI 95 % 0.06–0.81; p = 0.023), together with mucinous histological type (OR 0.40, CI 90 % 0.18–0.92). MSI is a relevant prognostic factor in stage pT3N0M0 colon cancer suitable to discriminate those patients with a high risk of relapse.  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