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   2173篇
  免费   133篇
  国内免费   3篇
耳鼻咽喉   13篇
儿科学   51篇
妇产科学   32篇
基础医学   309篇
口腔科学   45篇
临床医学   195篇
内科学   509篇
皮肤病学   70篇
神经病学   213篇
特种医学   18篇
外科学   258篇
综合类   2篇
一般理论   2篇
预防医学   202篇
眼科学   19篇
药学   174篇
中国医学   6篇
肿瘤学   191篇
  2024年   2篇
  2023年   19篇
  2022年   64篇
  2021年   128篇
  2020年   50篇
  2019年   106篇
  2018年   113篇
  2017年   69篇
  2016年   57篇
  2015年   68篇
  2014年   111篇
  2013年   129篇
  2012年   205篇
  2011年   184篇
  2010年   118篇
  2009年   106篇
  2008年   136篇
  2007年   106篇
  2006年   110篇
  2005年   118篇
  2004年   80篇
  2003年   74篇
  2002年   69篇
  2001年   13篇
  2000年   7篇
  1999年   5篇
  1998年   13篇
  1997年   12篇
  1996年   4篇
  1995年   6篇
  1994年   5篇
  1993年   6篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1988年   4篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
排序方式: 共有2309条查询结果,搜索用时 0 毫秒
51.
52.
Journal of Neurology - MRI atrophy predicts cognitive status in AD. However, this relationship has not been investigated in early-onset AD (EOAD, < 65 years) patients...  相似文献   
53.

Introduction and objectives

In the general population, heart events occur more often during early morning, on Mondays, and during winter. However, the chronobiology of death in heart failure has not been analyzed. The aim of this study was to determine the circadian, day of the week, and seasonal variability of all-cause mortality in chronic heart failure.

Methods

This was an analysis of all consecutive heart failure patients followed in a heart failure unit from January 2003 to December 2008. The circadian moment of death was analyzed at 6-h intervals and was determined by reviewing medical records and by information provided by the relatives.

Results

Of 1196 patients (mean [standard deviation] age, 69 [13] years; 62% male), 418 (34.9%) died during a mean (standard deviation) follow-up of 29 (21) months. Survivors were younger, had higher body mass index, left ventricular ejection fraction, glomerular filtration rate, hemoglobin and sodium levels, and lower Framingham risk scores, amino-terminal pro-B type natriuretic peptide, troponin T, and urate values. They were more frequently treated with angiotensin receptor blockers, beta-blockers, mineralocorticoids receptor antagonists, digoxin, nitrates, hydralazine, statins, loop diuretics, and thiazides. The analysis of the circadian and weekly variability did not reveal significant differences between the four 6-h intervals or the days of the week. Mortality occurred more frequently during the winter (30.6%) compared with the other seasons (P = .024).

Conclusions

All cause mortality does not follow a circadian pattern, but a seasonal rhythm in patients with heart failure. This finding is in contrast to the circadian rhythmicity of cardiovascular events reported in the general population.Full English text available from:www.revespcardiol.org/en  相似文献   
54.
55.
Glioblastomas (GB) are brain tumours with poor prognosis even after aggressive therapy. Improvements in both therapeutic and follow‐up strategies are urgently needed. In previous work we described an oscillatory pattern of response to Temozolomide (TMZ) using a standard administration protocol, detected through MRSI‐based machine learning approaches. In the present work, we have introduced the Immune‐Enhancing Metronomic Schedule (IMS) with an every 6‐d TMZ administration at 60 mg/kg and investigated the consistence of such oscillatory behaviour. A total of n = 17 GL261 GB tumour‐bearing C57BL/6j mice were studied with MRI/MRSI every 2 d, and the oscillatory behaviour (6.2 ± 1.5 d period from the TMZ administration day) was confirmed during response. Furthermore, IMS‐TMZ produced significant improvement in mice survival (22.5 ± 3.0 d for controls vs 135.8 ± 78.2 for TMZ‐treated), outperforming standard TMZ treatment. Histopathological correlation was investigated in selected tumour samples (n = 6) analyzing control and responding fields. Significant differences were found for CD3+ cells (lymphocytes, 3.3 ± 2.5 vs 4.8 ± 2.9, respectively) and Iba‐1 immunostained area (microglia/macrophages, 16.8% ± 9.7% and 21.9% ± 11.4%, respectively). Unexpectedly, during IMS‐TMZ treatment, tumours from some mice (n = 6) fully regressed and remained undetectable without further treatment for 1 mo. These animals were considered “cured” and a GL261 re‐challenge experiment performed, with no tumour reappearance in five out of six cases. Heterogeneous therapy response outcomes were detected in tumour‐bearing mice, and a selected group was investigated (n = 3 non‐responders, n = 6 relapsing tumours, n = 3 controls). PD‐L1 content was found ca. 3‐fold increased in the relapsing group when comparing with control and non‐responding groups, suggesting that increased lymphocyte inhibition could be associated to IMS‐TMZ failure. Overall, data suggest that host immune response has a relevant role in therapy response/escape in GL261 tumours under IMS‐TMZ therapy. This is associated to changes in the metabolomics pattern, oscillating every 6 d, in agreement with immune cycle length, which is being sampled by MRSI‐derived nosological images.  相似文献   
56.
Common variable immune deficiency (CVID) is an assorted group of primary diseases that clinically manifest with antibody deficiency, infection susceptibility, and autoimmunity. Heterozygous mutations in the gene encoding the tumor necrosis factor receptor superfamily member TACI are associated with CVID and autoimmune manifestations, whereas two mutated alleles prevent autoimmunity. To assess how the number of TACI mutations affects B cell activation and tolerance checkpoints, we analyzed healthy individuals and CVID patients carrying one or two TACI mutations. We found that TACI interacts with the cleaved, mature forms of TLR7 and TLR9 and plays an important role during B cell activation and the central removal of autoreactive B cells in healthy donors and CVID patients. However, only subjects with a single TACI mutation displayed a breached immune tolerance and secreted antinuclear antibodies (ANAs). These antibodies were associated with the presence of circulating B cell lymphoma 6–expressing T follicular helper (Tfh) cells, likely stimulating autoreactive B cells. Thus, TACI mutations may favor CVID by altering B cell activation with coincident impairment of central B cell tolerance, whereas residual B cell responsiveness in patients with one, but not two, TACI mutations enables autoimmune complications.  相似文献   
57.
58.
Lymphangioleiomyomatosis (LAM) is a rare disease that mainly affects women, particularly at fertile age. It is sporadic or associated with tuberous sclerosis complex. It is characterised by an abnormal proliferation of immature smooth muscle cells (SMC), which grow aberrantly in the airway, parenchyma, lymphatics and pulmonary blood vessels and which can gradually lead to respiratory failure. It affects several systems, affecting the lymphatic ganglia and causing abdominal tumours. Given its very low prevalence, a difficult to establish early diagnosis, absence of curative treatment and the difficulty in obtaining information, places LAM under the heading of the so-called Rare Diseases. There is a growing interest in the study of this disease which has led to the setting up of patient registers and an exponential growth in LAM research, both at a clinical level and cellular level.  相似文献   
59.
60.
Little is known about the consequences of short cycles of structured treatment interruption or definitive interruption of HAART for both T cell subset dynamics and T lymphoproliferative responses (LPR). Immunological follow-up was performed in 45 early chronical HIV-1-infected patients during short STI cycles during the first 12 weeks after the definitive interruption of HAART (DTI) and, thereafter, until VL reached a plateau. During STI cycles, CD8(+), CD8(+), CD28(+), activation markers and naive CD4(+) T cells increased significantly (p < 0.0001), while both naive CD8(+) and memory CD4(+) T cells decreased. During DTI, CD8(+) CD28(+) T cells fell and CD4(+) naive T cells stabilized and the rest of the T cell subsets presented changes similar to those during STI cycles. Despite a transient increase in LPR to recall antigens and HIV proteins during STI cycles, LPR to polyclonal stimuli and pathogens decreased over the study. Differences in T cell subset dynamics and LPR observed throughout the study suggest that multiple exposures to low levels of antigen could improve the immune system, mainly by driving T cell maturation. Conversely, higher and longer viral replication after cessation of HAART overwhelms the immune system. These data may help to guide future immune-based therapies.  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