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   641篇
  免费   33篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   33篇
妇产科学   1篇
基础医学   44篇
口腔科学   16篇
临床医学   68篇
内科学   140篇
皮肤病学   70篇
神经病学   28篇
特种医学   46篇
外科学   78篇
综合类   1篇
预防医学   8篇
眼科学   1篇
药学   101篇
中国医学   1篇
肿瘤学   38篇
  2023年   4篇
  2022年   3篇
  2021年   8篇
  2020年   6篇
  2019年   10篇
  2018年   11篇
  2017年   9篇
  2016年   16篇
  2015年   18篇
  2014年   23篇
  2013年   19篇
  2012年   47篇
  2011年   34篇
  2010年   21篇
  2009年   20篇
  2008年   41篇
  2007年   38篇
  2006年   38篇
  2005年   47篇
  2004年   35篇
  2003年   50篇
  2002年   32篇
  2001年   15篇
  2000年   14篇
  1999年   11篇
  1998年   5篇
  1997年   8篇
  1996年   11篇
  1995年   4篇
  1994年   5篇
  1992年   3篇
  1991年   2篇
  1990年   6篇
  1988年   4篇
  1986年   2篇
  1985年   2篇
  1984年   5篇
  1983年   3篇
  1982年   8篇
  1981年   3篇
  1980年   8篇
  1979年   4篇
  1978年   6篇
  1977年   2篇
  1975年   3篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1970年   1篇
  1966年   1篇
排序方式: 共有677条查询结果,搜索用时 15 毫秒
91.

Background

Ionizing irradiation is an effective treatment for malignant glioma (MG); however, a higher rate of recurrence with more aggressive phenotypes is a vital issue. Although epithelial-mesenchymal transition (EMT) is involved in irradiation-induced cancer progression, the role for such phenotypic transition in MG remains unknown.

Methods

To investigate the mechanism of irradiation-dependent tumor progression in MG, we performed immunohistochemistry (IHC) and qRT-PCR using primary and recurrent MG specimens, MG cell lines, and primary culture cells of MG. siRNA technique was used for MG cell lines.

Results

In 22 cases of clinically recurrent MG, the expression of the mesenchymal markers vimentin and CD44 was found to be increased by IHC. In paired identical MG of 7 patients, the expression of collagen, MMPs, and YKL-40 were also elevated in the recurrent MGs, suggesting the The Cancer Genome Atlas-based mesenchymal subtype. Among EMT regulators, sustained elevation of Snail was observed in MG cells at 21 days after irradiation. Cells exhibited an upregulation of migration, invasion, numbers of focal adhesion, and MMP-2 production, and all of these mesenchymal features were abrogated by Snail knockdown. Intriguingly, phosphorylation of ERK1/2 and GSK-3β were increased after irradiation in a Snail-dependent manner, and TGF-β was elevated in both fibroblasts and macrophages but not in MG cells after irradiation. It was noteworthy that irradiated cells also expressed stemness features such as SOX2 expression and tumor-forming potential in vivo.

Conclusions

We here propose a novel concept of glial-mesenchymal transition after irradiation in which the sustained Snail expression plays an essential role.  相似文献   
92.

Background

Evaluation of left ventricular (LV) diastolic function is essential for the management of heart failure. We verified whether LV diastolic function could be evaluated by measuring the fractional area change (FAC) using cine cardiovascular magnetic resonance (CMR).

Methods

We collected clinical data from 59 patients who underwent echocardiography and cine CMR. Normal, impaired relaxation, pseudonormal, and restrictive LV filling were observed in 15, 28, 11, and 5 patients, respectively. We calculated FAC during the first 30% of diastole (diastolic-index%) in the short-axis view, by tracing the contours on only three MR cine images.

Results

The diastolic index was significantly lower (p < 0.0001) in patients with impaired relaxation (32.4 ± 7.5), pseudonormal filling (25.4 ± 5.6), and restrictive filling (9.5 ± 1.5) compared to those with normal diastolic function (67.7 ± 10.8), and the index decreased significantly with worsening of diastolic dysfunction. The diastolic index correlated positively with early diastolic mitral annular velocity measured by tissue Doppler imaging (r = 0.75, p < 0.0001), respectively.

Conclusions

Measurement of FAC can be useful for the evaluation of LV diastolic function using cine CMR.  相似文献   
93.
Dyslipidemia     
Low-density lipoprotein (LDL) cholesterol is the most established risk factor for atherosclerotic disease such as coronary artery disease and cerebrovascular disease. High-density lipoprotein (HDL) cholesterol and nonHDL-C as well as small dense LDL, Remnant like particles cholesterol (RLP-C) and oxidized LDL are the secondary risk factors for atherosclerosis. It is important to integrate and control these risk factors for the prevention of atherosclerosis as a real endpoint of diagnosis and treatment of dyslipidemia.  相似文献   
94.
95.
96.
97.
Because some users develop depigmentation after the use of melanogenesis‐inhibiting products containing the quasi‐drug ingredient Rhododenol, Japanese Dermatological Association (JDA) established a Special Committee on the Safety of Cosmetics Containing Rhododenol on July 17, 2013 and management guide for dermatologists has been updated on the website in order to delineate the diagnostic criteria for Rhododenol‐induced leukoderma and provides a broad guide for standard treatment based on current knowledge. This guide is produced on the basis of the guide (version 7) updated on June 20, 2014 in the website. Rhododenol‐induced leukoderma refers to depigmentation of varying severity that develops after the use of cosmetics containing Rhododenol, mainly at the site of use. In most cases, repigmentation of part or all the affected area is evident after discontinuation. Histopathologically cellular infiltration around the hair follicles and melanophages are present in most cases. The number of melanocytes in the lesion is declined but not totally absent in most cases. Rhododenol itself is a good substrate for tyrosinase, resulting in the formation of Rhododenol metabolites (e.g., Rhododenol quinone). Melanocytes are damaged by Rhododenol metabolites during the subsequent metabolic process. The continued use of cosmetics containing Rhododenol thus induces tyrosinase activity‐dependent cytotoxicity in melanocytes in the epidermis at application sites, resulting in decreasing the amount of melanin produced by melanocytes; the addition of some other factor to this process is believed to subsequently cause the decrease or disappearance of melanocytes themselves from the epidermis.  相似文献   
98.
Precursors for Thy-1(+) dendritic epidermal T cells (DETC) develop as Vgamma3(+) T cells in the fetal thymus and become distributed in the adult skin. DETC are variably distributed from site to site and from strain to strain. To elucidate the basis of strain variation, we first compared the density of DETC in the ear epidermis among different mouse strains. In the ear epidermis, we detected the highest level of DETC in C57BL/6 mice, intermediate levels in C3H and CBA/J mice, and the lowest levels in other strains including BALB/c and 129 mice. Although BALB/c and 129+Ter/Sv mice showed higher levels of DETC in the abdomen than in the ear, the levels were significantly lower than C57BL/6 mice. Furthermore, in neonatal abdominal epidermis we detected considerably lower numbers of DETC in BALB/c and 129+Ter/Sv mice than in C57BL/6 mice. In contrast, Vgamma3(+) DETC precursors in the fetal thymus are rather increased in 129+Ter/Sv mice. These results suggest that fewer DETC precursors are seeded in the neonatal skin of BALB/c and 129+Ter/Sv mice and that their expansion in the skin during neonatal to adult stages does not reach the levels in C57BL/6 mice.  相似文献   
99.
Major thyroid diseases and recent progress in thyroid research are reviewed, including our clinical experiences and data on genetic analysis. Of the 19,944 patients receiving care in our endocrinology and metabolism department over the past 26 years(from 1974 to 2000), there were 4,471(22.4%) patients with thyroid diseases. Of these patients with thyroid disease, 37.3% had Graves' disease, 24.1% had Hashimoto's thyroiditis, and 22.2% had a benign thyroid tumor. Male-to-female ratio for Graves' disease was 1:3.2. The precise mechanism and genetic or environmental factors underlying the onset and progression of autoimmune thyroid disease need further investigation, although recent thyroid research, especially molecular level studies, has resulted in many new insights. Our genetic analysis of patients and experimental animals with thyroglobulin(Tg) abnormalities indicated the amino acids involved in the surface electric charge were important in maintaining the solid structure of Tg and thyroid hormone synthesis in addition to tyrosine and cysteine. In three patients with hyperthyroid Graves' disease, Hashimoto's thyroiditis or idiopathic hypothyroidism, followed by the author for 8 to 20 years, it was indicated that continued comprehensive care was needed for various episodes, even those arising from non-endocrine conditions, throughout the clinical course, although clinical and laboratory findings showed improvement of the thyroid disease itself.  相似文献   
100.

Background

Malaria is an important tropical disease and has remained a serious health problem in many countries. One of the critical complications of malarial infection is renal injury, such as acute renal failure and chronic glomerulopathy. Few animal models of nephropathy related to malarial infection have been reported. Therefore, we developed and investigated a novel malarial nephropathy model in mice infected by murine malaria parasites.

Methods

NC mice and C57BL/6J mice were infected with Ttwo different murine malaria parasites, Plasmodium (P.) chabaudi AS and P. yoelii 17X. After the infection, renal pathology and blood and urinary biochemistry were analyzed.

Results

NC mice infected by the murine malaria parasite P. chabaudi AS, but not P. yoelii 17X, developed mesangial proliferative glomerulonephritis with endothelial damage, and decreased serum albumin concentration and increased proteinuria. These pathological changes were accompanied by deposition of immunoglobulin G and complement component 3, mainly in the mesangium until day 4 and in the mesangium and glomerular capillaries from day 8. On day 21, renal pathology developed to focal segmental sclerosis according to light microscopy. In C57BL/6J mice, renal injuries were not observed from either parasite infection.

Conclusion

The clinical and pathological features of P. chabaudi AS infection in NC mice might be similar to quartan malarial nephropathy resulting from human malaria parasite P. malariae infection. The NC mouse model might therefore be useful in analyzing the underlying mechanisms and developing therapeutic approaches to malaria-related nephropathy.
  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