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   4066篇
  免费   331篇
  国内免费   24篇
耳鼻咽喉   35篇
儿科学   148篇
妇产科学   61篇
基础医学   755篇
口腔科学   32篇
临床医学   453篇
内科学   858篇
皮肤病学   68篇
神经病学   483篇
特种医学   74篇
外科学   445篇
综合类   14篇
一般理论   2篇
预防医学   371篇
眼科学   42篇
药学   277篇
中国医学   9篇
肿瘤学   294篇
  2024年   2篇
  2023年   40篇
  2022年   54篇
  2021年   102篇
  2020年   60篇
  2019年   102篇
  2018年   112篇
  2017年   73篇
  2016年   82篇
  2015年   105篇
  2014年   158篇
  2013年   204篇
  2012年   311篇
  2011年   345篇
  2010年   173篇
  2009年   173篇
  2008年   292篇
  2007年   288篇
  2006年   285篇
  2005年   279篇
  2004年   259篇
  2003年   281篇
  2002年   220篇
  2001年   30篇
  2000年   20篇
  1999年   33篇
  1998年   42篇
  1997年   52篇
  1996年   31篇
  1995年   23篇
  1994年   31篇
  1993年   33篇
  1992年   10篇
  1991年   17篇
  1990年   11篇
  1989年   10篇
  1988年   6篇
  1987年   5篇
  1986年   15篇
  1985年   3篇
  1984年   12篇
  1983年   4篇
  1982年   8篇
  1981年   6篇
  1980年   5篇
  1979年   2篇
  1978年   3篇
  1965年   1篇
  1964年   1篇
  1962年   1篇
排序方式: 共有4421条查询结果,搜索用时 15 毫秒
51.
Aims Previous research has shown that consistently not responding to alcohol‐related stimuli in a go/no‐go training procedure reduces drinking behaviour. This study aimed to examine further the mechanisms underlying this go/no‐go training effect. Design, setting and participants Fifty‐seven heavy drinkers were assigned randomly to two training conditions: in the beer/no‐go condition, alcohol‐related stimuli were always paired with a stopping response, while in the beer/go condition participants always responded to alcohol‐related stimuli. Participants were tested individually in a laboratory at Maastricht University. Measurements Weekly alcohol intake, implicit attitudes towards beer, approach–avoidance action tendencies towards beer and response inhibition were measured before and after the training. Findings Results showed a significant reduction in both implicit attitudes (P = 0.03) and alcohol intake (P = 0.02) in the beer/no‐go condition, but not in the beer/go condition. There were no significant training effects on action tendencies or response inhibition. Conclusions Repeatedly stopping pre‐potent responses towards alcohol‐related stimuli reduces excessive alcohol use via a devaluation of alcohol‐related stimuli rather than via increased inhibitory control over alcohol‐related responses.  相似文献   
52.
53.
The new incretin-based therapies, dipeptidyl peptidase-4 (DPP4) inhibitors and glucagon like peptide 1 (GLP1) receptor agonists are widely used for the treatment of type 2 diabetes because of their glucose-lowering capacity with low risk of hypoglycemia. As they are weight neutral or induce weight loss in this mostly overweight population, they are popular among clinicians and patients alike. Nonetheless, concerns have been raised about GLP1's trophic effects. While increased β cell mass observed in rodents sounds appealing for treatment of diabetes, there was also an increased incidence of medullary thyroid cancer (MTC) in some species. We reviewed literature available in the Medline database until March 2012. Safety signals have emerged for MTC and pancreatic carcinoma from adverse event databases in the United States and Europe. Considering the relatively short duration of these studies, it is more likely that premalignant lesions are stimulated in presence of GLP1, rather than new neoplasms induced. Moreover, interpreting results of animal studies is difficult because of species-specific differences in presence and density of GLP1 receptors. Furthermore, data are emerging suggesting beneficial effects of GLP1 on colon and breast cancer. In conclusion, presently, the benefits of using DPP4 inhibitors or GLP1 receptor agonists for treatment of type 2 diabetes outweigh the risks. Nonetheless, their safety profile should be monitored and their indications should be widened cautiously. At present they remain contra-indicated in patients with a personal or family history of MTC or multiple endocrine neoplasia type 2.  相似文献   
54.
Heart failure self-care is vital to achieving clinical stability and improved health outcomes. Yet despite the attention it has been given, in both research and clinical practice, effective self-care remains elusive. It is recognised that there are many patient factors that impact on attaining effective self-care skills. Systematic research is warranted to resolve the knowledge gap of how patients process information and develop the necessary self-care skills. In addition, sound screening tools are needed to assess factors that hinder the development of effective heart failure self-care skills. In this manner, education and support strategies can be applied on an individualised needs basis to enhance health outcomes.  相似文献   
55.
56.
Assessment of the early stages of fracture healing via X‐rays and computed tomography is limited by the low radio‐opacity of cartilage. We validated a method of contrast‐enhanced computed tomography (CECT) for non‐destructive identification of cartilage within a healing fracture callus. Closed, stabilized fractures in femora of C57BL/6 mice were harvested on post‐operative day 9.5 and imaged ex vivo with micro‐computed tomography (µCT) before and after incubation in a cationic contrast agent that preferentially accumulates in cartilage due to the high concentration of sulfated glycosaminoglycans in the tissue. Co‐registration of the pre‐ and post‐incubation images, followed by image subtraction, enabled two‐ and three‐dimensional delineation of mineralized tissue, soft callus, and cartilage. The areas of cartilage and callus identified with CECT were compared to those identified with the gold‐standard method of histomorphometry. No difference was found between the areas of cartilage measured by the two methods (p = 0.999). Callus area measured by CECT was smaller than, but strongly predictive of (R2 = 0.80, p < 0.001), the corresponding histomorphometric measurements. CECT also enabled qualitative identification of mineralized cartilage. These findings indicate that the CECT method provides accurate, quantitative, and non‐destructive visualization of the shape and composition of the fracture callus, even during the early stages of repair when little mineralized tissue is present. The non‐destructive nature of this method would allow subsequent analyses, such as mechanical testing, to be performed on the callus, thus enabling higher‐throughput, comprehensive investigations of bone healing. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 567–573, 2013  相似文献   
57.
58.
59.
Bacterial infections in the gastrointestinal tract represent a major global health problem, even in the presence of normally effective mucosal immune mechanisms. Milk fermented by Lactobacillus helveticus R389 (FM) or its non-bacterial fraction obtained by milk fermentation at controlled pH 6 (NBF) are able to activate the small intestine mucosal immune response according to previous studies. In this work we aimed at comparing their protection capacity against an infection by Salmonella enteritidis serovar Typhimurium and at studying the mechanisms involved. In a completely randomized design, BALB/c mice received FM or NBF for 2, 5 or 7 consecutive days, followed by a single oral challenge with S. Typhimurium (10(7) cells/mouse). The increase in the number of IgA+ cells in the lamina propria of the small intestine, after the feeding periods, was accompanied by an increase in the luminal content of total S-IgA. However, no antibodies were produced against the NBF. In mice given the FM or the NBF for 7 consecutive days, lower levels of liver colonization on day 7 post-challenge with S. Typhimurium, higher luminal contents of specific anti-Salmonella S-IgA, higher percentages of survival to infection and lower numbers of MIP-1alpha+ cells in the lamina propria were observed. In this work we observed that in both the FM or the NBF there are active principles that confer enhanced protection against S. Typhimurium infection. However, the mechanisms underlying mucosal immunomodulation and protection are different. In those mechanisms, the mucosal immune response would seem to be more involved than the competitive or exclusion mechanisms between L. helveticus R389 and S. enteritidis serovar Typhimurium.  相似文献   
60.
Myeloid cells bear Fc receptors (FcR) that mediate inflammatory signaling through the ITAM-containing FcRgamma adaptor. They express FcRgamma-associated FcalphaRI, which modulate either activating or inhibitory signaling depending on the type of ligand interaction. The role of FcalphaRIgamma in disease progression remains unknown, notably in IgA nephropathy (IgAN), one of major causes of end-stage renal disease, in which large amounts of circulating IgA-immune complexes (IC) may mediate receptor activation. To analyze the involvement of FcalphaRI activation in glomerulonephritis (GN), we generated Tg mice expressing a mutated, signaling-incompetent, human FcalphaRI(R209L) that cannot associate with FcRgamma. Like FcalphaRI(wt)-Tg mice, they developed mesangial IgA deposits but not macrophage infiltration. FcalphaRI activation in FcalphaRI(wt), but not in FcalphaRI(R209L), Tg mice resulted in marked inflammation with severe proteinuria and leukocyte infiltration in spontaneous IgAN or anti-glomerular basement membrane Ab-induced GN models. Receptor triggering of syngenically transferred FcalphaRI(wt) Tg macrophages into non-Tg animals induced their recruitment into injured kidneys during GN development. FcalphaRI(wt) cross-linking on macrophages activated MAP kinases and production of TNF-alpha and MCP-1. Moreover, IgA-IC from IgAN patients activated FcalphaRI and induced TNF-alpha production. Thus, FcalphaRI activation mediates GN progression by initiating a cytokine/chemokine cascade that promotes leukocyte recruitment and kidney damage.  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