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   994篇
  免费   77篇
  国内免费   8篇
耳鼻咽喉   16篇
儿科学   33篇
妇产科学   4篇
基础医学   196篇
口腔科学   72篇
临床医学   82篇
内科学   258篇
皮肤病学   31篇
神经病学   40篇
特种医学   49篇
外科学   104篇
综合类   5篇
预防医学   22篇
眼科学   7篇
药学   68篇
中国医学   1篇
肿瘤学   91篇
  2023年   16篇
  2022年   12篇
  2021年   85篇
  2020年   34篇
  2019年   49篇
  2018年   48篇
  2017年   33篇
  2016年   39篇
  2015年   40篇
  2014年   40篇
  2013年   47篇
  2012年   64篇
  2011年   65篇
  2010年   38篇
  2009年   16篇
  2008年   47篇
  2007年   49篇
  2006年   31篇
  2005年   31篇
  2004年   32篇
  2003年   25篇
  2002年   26篇
  2001年   24篇
  2000年   24篇
  1999年   14篇
  1998年   11篇
  1997年   3篇
  1996年   8篇
  1995年   4篇
  1994年   5篇
  1993年   5篇
  1992年   8篇
  1991年   13篇
  1990年   8篇
  1989年   10篇
  1988年   8篇
  1987年   8篇
  1986年   8篇
  1985年   12篇
  1984年   5篇
  1983年   2篇
  1980年   2篇
  1979年   4篇
  1976年   1篇
  1974年   2篇
  1972年   4篇
  1971年   4篇
  1970年   5篇
  1969年   4篇
  1968年   4篇
排序方式: 共有1079条查询结果,搜索用时 296 毫秒
1.
In order to find useful information for the establishment of new treatment method to alcohol dependence, we investigated the change of the body image of patients with alcohol dependence before and after the treatment. HABIT (Haga Body Image Test), a questionnaire about body image developed in department of psychiatry in Kyoto Prefectural University of Medicine, was used to examine the change of body image between pre- and post-3-month conventional treatment program in 46 patients with alcohol dependence hospitalized into special institutions for treatment of the disease in Kyoto. Patients with poor outcome of the treatment showed improvement of body image on visceral function, feeling of appetite and outward appearance, while patients with good outcome indicated no significant change in these aspects. This finding likely suggests that the treatment would result in good outcome in patients having stable feeling of physical health, and the cognitive treatment approach about these aspects of body image should be performed on the patients with poor treatment outcome. On the other hand, the body image about motor function showed significantly higher score in the patients approach for the patients with poor outcome to become aware of their physical activity would be effective.  相似文献   
2.
Notch receptors and their ligands contribute to many developmental systems, but it is not apparent how they function after birth, as their null mutants develop severe defects during embryogenesis. Here we used the Cre-loxP system to delete the Delta-like 1 gene (Dll1) after birth and demonstrated the complete disappearance of splenic marginal zone B cells in Dll1-null mice. In contrast, T cell development was unaffected. These results demonstrated that Dll1 was dispensable as a ligand for Notch1 at the branch point of T cell-B cell development but was essential for the generation of marginal zone B cells. Thus, Notch signaling is essential for lymphocyte development in vivo, but there is a redundancy of Notch-Notch ligand signaling that can drive T cell development within the thymus.  相似文献   
3.
A deficiency of citrin, which is encoded by the SLC25A13 gene, causes both adult-onset type II citrullinemia (CTLN2) and neonatal intrahepatic cholestasis (NICCD). We analyzed 16 patients with NICCD to clarify the clinical features of the disease. Severe intrahepatic cholestasis with fatty liver was the most common symptom, but the accompanying clinical features were variable, namely; suspected cases of neonatal hepatitis or biliary atresia, positive results from newborn screening, tyrosinemia, failure to thrive, hemolytic anemia, bleeding tendencies and ketotic hypoglycemia. Laboratory data showed elevated serum bile acid levels, hypoproteinemia, low levels of vitamin K-dependent coagulation factors, and hypergalactosemia. Hypercitrullinemia was detected in 11 out of 15 patients examined. Most of the patients were given a lactose-free and/or medium chain triglycerides-enriched formula and lipid-soluble vitamins. The prognosis of the 16 patients is going fairy well at present, but we should observe these patients carefully to see if they manifest any symptom of CTLN2 in the future.  相似文献   
4.
Sequential treatment with lamivudine and interferon (IFN) has induced sustained biochemical and virologic responses in the majority of patients with chronic hepatitis B in France. However, the efficacy of sequential treatment in patients with chronic hepatitis B virus (HBV) genotype C infection has not been evaluated. Twenty-four HBe antigen-positive patients were treated with 100 mg lamivudine alone for 16-32 weeks, then with both 6 MU IFN-beta and lamivudine for 4 weeks, and lastly with IFN-beta alone for 20 weeks. Sustained response was achieved in 7 (29%) patients 24 weeks after the end of therapy. No lamivudine-resistant variants emerged in any patient. Hepatitis flare occurred in 3 patients after the withdrawal of lamivudine, but none had decompensation. The patients with sustained response were significantly younger at baseline (p = 0.033) and had a significantly lower HBV DNA level at the start of IFN (p = 0.020) than those without sustained response. In conclusion, the rate of response to sequential therapy with lamivudine and IFN in HBe antigen-positive patients with HBV genotype C infection was lower than the rate reported previously. Patients who were young or who had a favorable virologic response to lamivudine were more likely to have a sustained response.  相似文献   
5.
Mold filling of titanium alloys in two different wedge-shaped molds   总被引:2,自引:0,他引:2  
Shimizu H  Habu T  Takada Y  Watanabe K  Okuno O  Okabe T 《Biomaterials》2002,23(11):2275-2281
Pure titanium and titanium alloys are potential materials for the fabrication of cast dental appliances. One important factor in producing sound castings is the capacity of the metal to fill the mold. This study used a wedge-shaped mold to compare the mold filling of titanium with that of conventional dental casting alloys. The metals used were CP Ti, Ti-6Al-7Nb, Ti-6Al-4V, Ti with 1 and 4wt% Cu and ADA Type III gold alloy and an Ni-Cr alloy. The castings were cut into four pieces parallel to the triangular surface. Mold filling was evaluated as the distance between the tip of the cast wedge and theoretical tip of the triangle. The mold filling of the gold alloy was superior compared to all the metals tested, while the mold filling of the Ni-Cr alloy was the worst. There were no statistical differences at the 30 degrees marginal angle for all the cast titanium metals. At the sharper 15 degrees angle, CP Ti and Ti-6Al-7Nb was superior to both the Ti-Cu alloys. Although the mold filling of titanium was inferior compared to the gold alloy, the data justify the use of titanium for the production of dental appliances.  相似文献   
6.
The response of chronic hepatitis C to interferon (IFN) treatment is classified as complete response (CR), biochemical response (BR), or no response (NR). Several studies have found no difference in prevention of hepatocellular carcinoma by IFN therapy between patients with CR and those with BR. We investigated whether specific human leukocyte antigen (HLA) alleles were associated with response to IFN, especially BR, in 138 patients with chronic hepatitis C. Comparing patients with and without CR, male, a low viral titer, genotype 2a or 2b, HLA-B55, and HLA-DRB1-0803 were more common in the group with CR. Multivariate analysis showed that age (adjusted odds ratio [OR], 0.95 by every year [95% confidence interval [CI] 0.90 - 0.99], p = 0.028), genotype 2a or 2b (5.21 [95% CI 1.63 - 16.6], p = 0.005), and low viral titer (8.58 (2.66 - 27.7), p < 0.001) were associated with CR. Comparing patients with BR and NR, the pretreatment alanine aminotransferase (ALT) level was lower in the BR group (p < 0.001). Both HLA-B7 and HLA-DRB1-0101 were more common in this group (p = 0.002). As the alleles HLA-B7 and HLA-DRB1-0101 were in linkage disequilibrium, the HLA-B7-DRB1-0101 haplotype may be associated with BR. Multivariate analysis indicated that a low ALT level (0.98 by every 1 IU/L [95% CI 0.98 - 0.99], p = 0.001) and HLA-B7-DRB1-0101 haplotype (32.3 [95% CI 1.50 - 693.1], p = 0.026) contributed significantly to BR. This study suggested that host HLA expression, but not viral factors, can influence BR.  相似文献   
7.
The effects of IL-7 on the growth and differentiation of thymocyteswere analyzed using murine fetal thymua organ cultures (FTOC)in the presence of mAbs specific for the conventional IL-7 receptor(1L-7R) and for the common (c) chain. In FTOC, the developmentof CD4CD8 double-negative thymocytes to CD4+CD8+double-positive (DP) and CD4+ or CD8+ single-positive (SP) cellswas not completely blocked by adding these mAbs, although cellgrowth was reduced by the treatment. To define a developingstage sensitive to the mAbs, most immature thymocytes, Pgp-1+c-kit cells, were cultured in the 2-deoxyguartosine treatedfetal thymus. In the presence of both mAbs in the culture, neitherDP nor SP thymocytes developed whereas either of the mAbs partiallyblocked their development. These results indicate that the Cchain is involved in early T cell development as an indispensablesubunlt of the functional IL-7 receptor complex.  相似文献   
8.
BACKGROUND: It has been reported that dietary nucleotides enhance T helper cell activities. In this study, we have determined the effects of dietary nucleotides on antigen-specific Th1 and Th2 responses and IgE responses. METHODS: Ovalbumin (OVA)-specific T cell receptor (TCR) transgenic (OVA-TCR Tg) mice, 3 weeks old, were fed a nucleotide-free diet (NT(-) diet) or the NT(-) diet supplemented with dietary nucleotides (NT(+) diet) for 4 weeks. Cytokine production by spleen cells and macrophages obtained from these mice was measured in vitro. BALB/c mice, 3 weeks old, immunized intraperitoneally with OVA adsorbed onto alum, were fed the NT(-) diet or the NT(+) diet for 4 weeks. Serum levels of antigen-specific antibodies in the BALB/c mice were determined by ELISA. RESULTS: The level of production of antigen-specific interferon-gamma by spleen cells was significantly higher in the OVA-TCR Tg mice fed the NT(+) diet than in the control mice. The levels of secretion of bioactive IL-12 by spleen cells and peritoneal macrophages were also significantly increased in the NT(+) diet group. The serum OVA-specific IgE level was significantly decreased in BALB/c mice fed the NT(+) diet compared with those fed the NT(-) diet. CONCLUSION: These results show that dietary nucleotides up-regulate the antigen-specific Th1 immune response through the enhancement of IL-12 production and suppress the antigen-specific IgE response.  相似文献   
9.
In the present study, we established transgenic mice overexpressing Del1, a ligand of integrins, to examine the effect of overexpression of Del1 on vascular morphogenesis. In the wild-type mouse, mesenteric vessels are shaped like rakes consisting of a long stalk and short branches at the periphery. In contrast, those in transgenic mice showed typical dendritic architecture consisting of a few large primary branches with smaller spreading branches. The phenotype of mice overexpressing Del1 suggests the existence of a tissue-specific mechanism for branching morphogenesis in the mesentery.  相似文献   
10.
Sato T  Ohno S  Hayashi T  Sato C  Kohu K  Satake M  Habu S 《Immunity》2005,22(3):317-328
To understand how CD8 expression is regulated during the transition process from CD4+8+ (CD4 and CD8 double positive, DP) to CD4-8+ (CD8 single positive, CD8SP) cells in the thymus, the involvement of Runx proteins in the alteration of chromatin configuration was investigated. Using the chromatin immunoprecipitation assay, we first demonstrated that Runx proteins bind to the stage-specific CD8 enhancer, as well as the CD4 silencer, in CD8SP thymocytes. Among Runx family members, Runx3 expression was initiated in DP thymocytes receiving a positive selection signal and increased in concert with differentiation to the CD8SP stage. Furthermore, reactivation of the CD8 gene, as well as CD4 silencing, was suppressed in positively selected thymocytes of Runx dominant-negative transgenic mice. These results suggest that Runx proteins, especially Runx3, are involved in lineage specification of CD8 T cells and provide important information for understanding the mechanism for the mutually exclusive expression of coreceptors in mature thymocytes.  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