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   1276篇
  免费   85篇
  国内免费   15篇
耳鼻咽喉   4篇
儿科学   44篇
妇产科学   11篇
基础医学   209篇
口腔科学   13篇
临床医学   71篇
内科学   261篇
皮肤病学   26篇
神经病学   73篇
特种医学   189篇
外科学   260篇
综合类   8篇
预防医学   29篇
眼科学   21篇
药学   95篇
中国医学   12篇
肿瘤学   50篇
  2023年   7篇
  2022年   13篇
  2021年   46篇
  2020年   12篇
  2019年   32篇
  2018年   40篇
  2017年   30篇
  2016年   32篇
  2015年   78篇
  2014年   77篇
  2013年   83篇
  2012年   122篇
  2011年   133篇
  2010年   75篇
  2009年   62篇
  2008年   97篇
  2007年   89篇
  2006年   61篇
  2005年   60篇
  2004年   50篇
  2003年   55篇
  2002年   31篇
  2001年   19篇
  2000年   18篇
  1999年   4篇
  1998年   13篇
  1997年   3篇
  1996年   6篇
  1995年   4篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   3篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
排序方式: 共有1376条查询结果,搜索用时 15 毫秒
51.
Fas-associated death domain (FADD) plays a crucial role during death receptor-mediated apoptosis. In addition, FADD possesses apoptosis-independent activities, including cell-cycle regulation and cell proliferation regulated by the phosphorylation of FADD at Ser194. The aim of this study was to explore the possibility whether alteration of phosphorylated FADD (p-FADD) expression might be a characteristic of gastric cancer. We analyzed the expression of p-FADD protein in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray approach. In the normal gastric mucosal cells, surface and glandular epithelial cells evenly expressed p-FADD in the nuclei but not in the cytoplasm. In the cancers, p-FADD expression was detected in 38 cases (63%) of the gastric carcinomas, but there was no p-FADD immunostaining in the remaining 22 cancers (37%). Of note, p-FADD immunostaining was observed in cytoplasm/nuclei (20 cancers; 33%) and cytoplasm (18 cancers; 30%). There was no significant association of p-FADD expression with clinocopathological characteristics, including invasion, metastasis, and stage. Our data showed that the expression of p-FADD in gastric cancers was heterogenous in its location compared to the uniform nuclear expression of p-FADD in normal gastric cells. Many of the cancers (67%) were devoid of nuclear p-FADD, suggesting that p-FADD functions in the nucleus may be perturbed in the cancers. Also, p-FADD expression in the cytoplasm in a large fraction of the cancers (63%), not seen in the normal cells, suggested that the cell death functions of p-FADD could be altered in the cancer cells.  相似文献   
52.
To investigate the role of CD8alpha(+) DCs in the development of collagen-induced arthritis (CIA). The immunogenic properties of CD8alpha(+) and CD8alpha(-) DC subsets were investigated by mixed-lymphocyte reaction and cytokine enzyme-linked immunoassay. CII-pulsed CD8alpha(+) DCs or CD8alpha(-) DCs with CD4(+) T cells from CIA mice were adoptively transferred onto the hind footpad of DBA mice. The onset of arthritis and the arthritis index were examined for 14 weeks after adoptive transfer. Expression of MHC-II and CD80 but not CD86 and CD40 was higher in CD8alpha(+) DCs than in CD8alpha(-) DCs from the spleens of CIA mice. Culturing CD8alpha(+) DCs with CD4(+) T cells significantly increased the proliferative response of CD4(+) T cells in the presence of CII. The production of interleukin (IL)-12p70, IL-17, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha was slightly increased in CD8alpha(+) DCs than in CD8alpha(-) DCs. DBA/1 mice that were adoptively transferred with CII-pulsed CD8alpha(+) DCs and CD4(+) T cells into the footpads showed accelerated onset of CIA compared to control group. By contrast, CD8alpha(-) DCs showed a partial inhibitory effect on CIA. These findings show that CD8alpha(+) DCs accelerated the onset of CIA when aoptively transferred with CD4(+) T cells and that CD8alpha(+) DCs provoke the development of CIA probably by stimulating the immune responses of CII-reactive CD4(+) T cells and by increasing the production of inflammatory cytokines.  相似文献   
53.
PURPOSE: Virulent gene expression in Staphylococcus aureus is controlled by regulators such as the accessory gene regulator (agr). Strains can be divided into four major agr groups (agr I-IV) on the basis of agrD and agrC polymorphisms. The purpose of this study was to define the proportion of agr I, II, and III polymorphisms and to compare the clinical characteristics between group I and non-group I polymorphisms of methicillin-resistant Staphylococcus aureus (MRSA) strains in a Korean tertiary care teaching hospital. MATERIALS AND METHODS: A total of 158 clinical isolates were evaluated by RFLPs (restriction fragment length polymorphisms). RESULTS: The mean age of the patients was 50.2 +/- 21.9 years old. There were 74 (49.3%), 66 (44.0%), 10 (6.7%), 7 (4.4%), and 1 (0.6%) strains in agr group I, II, III, I + II, and I + III polymorphisms, respectively. Only ear infections were a statistically significant clinical parameter according to univariate (p=0.001) and multivariate analysis (OR, 4.721 (1.273-17.508), p=0.020). CONCLUSION: This study suggests that agr group I is the most prevalent in Korea, and ear infections are correlated with the group I polymorphism, which is a different clinical trend from western countries. It can also be inferred that community-acquired MRSA correlates with agr group I.  相似文献   
54.
PURPOSE: Diabetic nephropathy is the most serious of complications in diabetes mellitus. Thiazolidinedione (TZD) is thought to ameliorate diabetic nephropathy; however, the mechanism underlying this effect has not been elucidated. We hypothesized that the vascular endothelial growth factor (VEGF) participates in the pathogenesis of diabetic nephropathy and that TZD may be beneficial for the treatment of diabetic nephropathy because of the effect it has on VEGF. MATERIALS AND METHODS: 23 Otsuka- Long-Evans-Tokushima-Fatty (OLETF) rats and eight control Long-Evans-Tokushima-Otsuka (LETO) rats were divided into the following four groups: LETO group, control OLETF group, pioglitazone treated group (10mg/ kg/day), and rosiglitazone treated group (3mg/kg/day). RESULTS: A progressive increase in urinary protein excretion was observed in the diabetic rats. Glomerular VEGF expression in the control OLETF rats was significantly higher than in the control LETO rats. However, there was a significant reduction in both the glomerular VEGF expression and the VEGF mRNA levels after treatment with pioglitazone and rosiglitazone. The twenty-four hour urine protein levels were significantly decreased in both groups of the treated OLETF rats. CONCLUSION: These results suggest that TZD may have beneficial effects on diabetic nephropathy by reducing the VEGF expression.  相似文献   
55.
Twin Pulse Life Support, T-PLS™ has received the CE mark (2003) and Korea Food and Drug Administration (KFDA) approval (2004) for short-term application as an Extracorporeal Life Support system (ECLS). T-PLS’s original intention was to apply for not only short-term but also long-term application such as Extracorporeal ventricular assist device (VAD). Hence, a long-term durability test was conducted. The 1-year reliability of the systems tested in this study did not meet the STS/ASAIO standard of 80% reliability with 60% confidence for a 1-year mission life. However, without the disposable units, which are only designed to operate for 6 h, the 1-year reliability exceeded the STS/ASAIO standard of 80% reliability with 60% confidence. In this study, by using the existing analysis methods and analyzing the root cause of the failure used by a numerical analysis. As eliminating or mitigating of the root cause of the failure, we improved the durability of blood chamber and evaluated the performance of the modified system via the hemolysis test.  相似文献   
56.
Bartonella species cause serious human infections globally, including bacillary angiomatosis, Oroya fever, trench fever, and endocarditis. We describe a patient who had fever and splenomegaly after traveling to Peru and also had bacteremia from an organism that resembled Bartonella bacilliformis, the causative agent of Oroya fever, which is endemic to Peru. However, genetic analyses revealed that this fastidious bacterium represented a previously uncultured and unnamed bartonella species, closely related to B. clarridgeiae and more distantly related to B. bacilliformis. We characterized this isolate, including its ability to cause fever and sustained bacteremia in a rhesus macaque. The route of infection and burden of human disease associated with this newly described pathogen are currently unknown.  相似文献   
57.
Lee SH  Jeong EG  Nam SW  Lee JY  Yoo NJ  Lee SH 《Pathology》2007,39(3):326-329
AIMS: Mounting evidence indicates that alterations of protein kinase signalling pathways play crucial roles in the pathogenesis of cancers. Gab2 (Grb2-associated binding protein 2), a member of the family of Gab scaffolding adaptors, transmits and amplifies the signals from receptor tyrosine kinases. A recent study demonstrated that Gab protein was over-expressed in breast cancers, and the over-expressed Gab2 increased proliferation and invasion of the cells, indicating that Gab2 is an oncogenic protein. However, the roles of Gab in other cancers are largely unknown. METHODS: In this study, to see whether Gab2 expression could be a characteristic of gastric cancers, we analysed the expression of Gab2 in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray. RESULTS: In the normal gastric mucosal epithelial cells, Gab2 protein was expressed in parietal and zymogen cells, but not in other mucosal epithelial cells. In the cancer cells, Gab2 expression was detected in 40 (67%) of the 60 gastric adenocarcinomas. The Gab2 expression was observed in 12 (60%) of the 20 early gastric carcinomas and 28 (70%) of the 40 advanced gastric carcinomas. There was no significant association of Gab2 expression with clinocopathological characteristics, including invasion, metastasis and stage. CONCLUSION: Our data indicate that Gab2 over-expression is a feature not only of breast cancers, but also of gastric cancers. Increased expression of Gab2 in malignant gastric cells compared with normal epithelial cells suggests that Gab2 expression may play a role in gastric cancer development.  相似文献   
58.
59.
60.
AIM: To describe and compare pathologic findings in eyes enucleated after superselective ophthalmic arterial chemotherapy (SOAC) or SOAC with intravenous chemotherapy (IVC) for retinoblastoma. METHODS: Medical records between January 1st, 2014 and June 31st, 2017 were retrospectively analyzed, and pathologic findings were recorded. This study included 36 eyes from 22 (61.1%) male and 14 (38.9%) female patients. Nineteen of 36 (52.8%) eyes received SOAC (mean=3, range=1-7) as primary treatment, and 17 of 36 (47.2%) eyes received SOAC (mean=3.7, range=1-10) after IVC (mean=6.1, range=2-11). Tumor extension including choroidal invasion (n=9, 25%), optic nerve invasion (n=5, 13.9%) and anterior segment invasion (n=5, 13.9%) were recorded. RESULTS: Histopathologic evidence of ischemic damage in the retina and choroid was found in 28 (77.8%) eyes. Thrombosed blood vessels were identified in 9 (25%) eyes, including orbital artery in the retrobulbar orbit (n=1), intrascleral vessels (n=4), and chorioretinal vessels (n=6). Fibrotic changes were found in extraocular muscles (n=5, 13.9%) and optic nerve (n=5, 13.9%). Varying degrees of scleral degeneration were found in all eyes. In statistical analysis, there was no significant difference in clinical and pathologic changes between SOAC group and SOAC with IVC group except for optic nerve invasion (P=0.047). CONCLUSION: SOAC for retinoblastoma can result in ocular toxicity, and SOAC with IVC did not increase the toxicity but reduced the incidence of optic nerve invasion.  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