全文获取类型
收费全文 | 2659篇 |
免费 | 166篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 133篇 |
妇产科学 | 76篇 |
基础医学 | 424篇 |
口腔科学 | 87篇 |
临床医学 | 176篇 |
内科学 | 495篇 |
皮肤病学 | 18篇 |
神经病学 | 180篇 |
特种医学 | 144篇 |
外科学 | 275篇 |
综合类 | 61篇 |
一般理论 | 1篇 |
预防医学 | 322篇 |
眼科学 | 45篇 |
药学 | 141篇 |
中国医学 | 5篇 |
肿瘤学 | 240篇 |
出版年
2023年 | 17篇 |
2022年 | 33篇 |
2021年 | 77篇 |
2020年 | 48篇 |
2019年 | 55篇 |
2018年 | 73篇 |
2017年 | 65篇 |
2016年 | 58篇 |
2015年 | 52篇 |
2014年 | 79篇 |
2013年 | 117篇 |
2012年 | 134篇 |
2011年 | 146篇 |
2010年 | 101篇 |
2009年 | 102篇 |
2008年 | 130篇 |
2007年 | 136篇 |
2006年 | 153篇 |
2005年 | 149篇 |
2004年 | 111篇 |
2003年 | 85篇 |
2002年 | 72篇 |
2001年 | 72篇 |
2000年 | 83篇 |
1999年 | 64篇 |
1998年 | 37篇 |
1997年 | 28篇 |
1996年 | 37篇 |
1995年 | 19篇 |
1994年 | 30篇 |
1993年 | 35篇 |
1992年 | 47篇 |
1991年 | 34篇 |
1990年 | 36篇 |
1989年 | 46篇 |
1988年 | 39篇 |
1987年 | 26篇 |
1986年 | 25篇 |
1985年 | 27篇 |
1984年 | 11篇 |
1983年 | 17篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1967年 | 6篇 |
排序方式: 共有2833条查询结果,搜索用时 31 毫秒
81.
Andries C. Bloem Tanja Lamme Martin de Smet Henriette Kok Wim Vooijs John Wijdenes Saskia E. Boom & Henk M. Lokhorst 《British journal of haematology》1998,100(1):166-175
Long-term bone marrow cultured stromal cells (LTBMC) produce IL-6 after contact with tumour cells from multiple myeloma patients. We found that LTBMC could substitute for exogenous IL-6 in the stimulation of bone marrow plasma cells from myeloma patients with active disease in short-term cultures. In addition, tumour cells of some patients with inactive disease, which were unresponsive to exogenous IL-6, were induced to IL-6-dependent growth after LTBMC co-culture. To study the role of LTBMC in myeloma tumour growth in vitro , plasma cell lines UM-2 and UM-3 were selected. UM-2 and UM-3 grew in contact with LTBMC and proliferation was blocked by antibodies against IL-6, IL-6 receptor (IL-6R, gp80, CD126) or the common signal transducing unit, gp130 (CD130). Culture with IL-6 alone or combined with GM-CSF resulted in cell death via apoptosis. The combination of IL-6 with soluble gp80, however, maintained in vitro proliferation of UM-2 and UM-3 cells. These data imply that LTBMC regulate myeloma growth in vitro via production of IL-6, possibly via induction of a functional IL-6 receptor on the tumour cells. 相似文献
82.
83.
Liesbeth Mollema Irene Anhai Harmsen Emma Broekhuizen Rutger Clijnk Hester De Melker Theo Paulussen Gerjo Kok Robert Ruiter Enny Das 《Journal of medical Internet research》2015,17(5)
Background
In May 2013, a measles outbreak began in the Netherlands among Orthodox Protestants who often refuse vaccination for religious reasons.Objective
Our aim was to compare the number of messages expressed on Twitter and other social media during the measles outbreak with the number of online news articles and the number of reported measles cases to answer the question if and when social media reflect public opinion patterns versus disease patterns.Methods
We analyzed measles-related tweets, other social media messages, and online newspaper articles over a 7-month period (April 15 to November 11, 2013) with regard to topic and sentiment. Thematic analysis was used to structure and analyze the topics.Results
There was a stronger correlation between the weekly number of social media messages and the weekly number of online news articles (P<.001 for both tweets and other social media messages) than between the weekly number of social media messages and the weekly number of reported measles cases (P=.003 and P=.048 for tweets and other social media messages, respectively), especially after the summer break. All data sources showed 3 large peaks, possibly triggered by announcements about the measles outbreak by the Dutch National Institute for Public Health and the Environment and statements made by well-known politicians. Most messages informed the public about the measles outbreak (ie, about the number of measles cases) (93/165, 56.4%) followed by messages about preventive measures taken to control the measles spread (47/132, 35.6%). The leading opinion expressed was frustration regarding people who do not vaccinate because of religious reasons (42/88, 48%).Conclusions
The monitoring of online (social) media might be useful for improving communication policies aiming to preserve vaccination acceptability among the general public. Data extracted from online (social) media provide insight into the opinions that are at a certain moment salient among the public, which enables public health institutes to respond immediately and appropriately to those public concerns. More research is required to develop an automatic coding system that captures content and user’s characteristics that are most relevant to the diseases within the National Immunization Program and related public health events and can inform official responses. 相似文献84.
Sheena G Sullivan Sandra Carlson Allen C Cheng Monique BN Chilver Dominic E Dwyer Melissa Irwin Jen Kok Kristine Macartney Jennifer MacLachlan Cara Minney-Smith David Smith Nigel Stocks Janette Taylor Ian G Barr 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2020,25(47)
85.
Thye Foo Choo Mohamad Amran Mohd Salleh Kuan Ying Kok Khamirul Amin Matori Suraya Abdul Rashid 《Materials》2020,13(22)
Grog is an additive material that plays important roles in ceramic making. It improves the fabrication process of green bodies as well as the physical properties of fired bodies. Few low-cost materials and wastes have found their application as grog in recent years, thus encouraging the replacement of commercial grogs with cost-saving materials. Coal fly ash, a combustion waste produced by coal-fired power plant, has the potential to be converted into grog owing to its small particle sizes and high content of silica and alumina. In this study, grog was derived from coal fly ash and mixed with kaolin clay to produce ceramics. Effects of the grog addition on the resultant ceramics were investigated. It was found that, to a certain extent, the grog addition reduced the firing shrinkage and increased the total porosity of the ceramics. The dimensional stability of the ceramics at a firing temperature of 1200 °C was also not noticeably affected by the grog. However, the grog addition in general had negative effects on the biaxial flexural strength and refractoriness of the ceramics. 相似文献
86.
Soo Young Kim Chong-Woo Bae Chang Kok Hahm Hye Min Cho 《Journal of Korean medical science》2014,29(2):172-175
The purpose of this study was to examine trends in duplicate publication in Korean medical articles indexed in the KoreaMed database from 2004 to 2009, before and after a campaign against scientific misconduct launched by the Korean Association of Medical Journal Editors in 2006. The study covered period from 2007 to 2012; and 5% of the articles indexed in KoreaMed were retrieved by random sampling. Three authors reviewed full texts of the retrieved articles. The pattern of duplicate publication, such as copy, salami slicing (fragmentation), and aggregation (imalas), was also determined. Before the launching ethics campaign, the national duplication rate in medical journals was relatively high: 5.9% in 2004, 6.0% in 2005, and 7.2% in 2006. However, duplication rate steadily declined to 4.5% in 2007, 2.8% in 2008, and 1.2 % in 2009. Of all duplicated articles, 53.4% were classified as copies, 27.8% as salami slicing, and 18.8% as aggregation (imalas). The decline in duplicate publication rate took place as a result of nationwide campaigns and monitoring by KoreaMed and KoreaMed Synapse, starting from 2006.
Graphical Abstract
相似文献87.
Ester Chai Kheng Yeoh Ling Choo Lim Siok Bian Ng Kok Yang Tan C. Rajasoorya 《Endocrine pathology》2014,25(3):302-306
The cribriform morular variant of papillary thyroid carcinoma (CMV-PTC) is a rare morphologic entity that is associated with familial adenomatous polyposis (FAP). We report a case of a young lady with an incidentally discovered right-sided neck nodule on ultrasonography with a diagnosis of CMV-PTC confirmed on thyroidectomy and review the literature associated with the clinical presentation, imaging characteristics, pathological findings and the association with FAP. 相似文献
88.
Daphne A. C. Stapels Kasra X. Ramyar Markus Bischoff Maren von K?ckritz-Blickwede Fin J. Milder Maartje Ruyken Janina Eisenbeis William J. McWhorter Mathias Herrmann Kok P. M. van Kessel Brian V. Geisbrecht Suzan H. M. Rooijakkers 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(36):13187-13192
Neutrophils are indispensable for clearing infections with the prominent human pathogen Staphylococcus aureus. Here, we report that S. aureus secretes a family of proteins that potently inhibits the activity of neutrophil serine proteases (NSPs): neutrophil elastase (NE), proteinase 3, and cathepsin G. The NSPs, but not related serine proteases, are specifically blocked by the extracellular adherence protein (Eap) and the functionally orphan Eap homologs EapH1 and EapH2, with inhibitory-constant values in the low-nanomolar range. Eap proteins are together essential for NSP inhibition by S. aureus in vitro and promote staphylococcal infection in vivo. The crystal structure of the EapH1/NE complex showed that Eap molecules constitute a unique class of noncovalent protease inhibitors that occlude the catalytic cleft of NSPs. These findings increase our insights into the complex pathogenesis of S. aureus infections and create opportunities to design novel treatment strategies for inflammatory conditions related to excessive NSP activity.Infections with the human pathogen Staphylococcus aureus constitute a major risk to human health. Although this bacterium harmlessly colonizes more than 30% of the population via the nose or skin, it causes severe morbidity and mortality upon invasion of deeper tissues (1). To avert these serious infections, neutrophils play an indispensable role (2). Neutrophil serine proteases (NSPs), including neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CG), are important for various neutrophil functions. Active NSPs are stored within the azurophilic granules (3), but upon neutrophil activation, they either enter the nucleus to regulate extracellular trap (NET) formation (4) or they are released into the extracellular milieu to kill certain bacteria (5), cleave bacterial virulence factors (5, 6), or regulate immune responses by cleaving chemokines and receptors (7). Recently, a fourth neutrophil serine protease, denoted NSP4, was identified (8).Given the central role of NSPs in neutrophil function, we wondered whether S. aureus had evolved mechanisms to cope with NSPs. In this study, we discover that S. aureus secretes a family of proteins that specifically and potently block NSPs: extracellular adherence protein (Eap) and the hitherto functional orphans Eap-homologue (EapH) 1 and 2. Structural studies presented here show that Eap molecules represent a unique class of noncovalent NSP inhibitors that is distinct from the well-known chelonianin class of inhibitors. These mechanistic insights can initiate development of novel, broad-range NSP inhibitors to be used in various inflammatory conditions. Furthermore, these insights increase our understanding of the pathogenicity of S. aureus and underline the exceptional capability of this pathogen to adapt to its host by modulating the immune response. 相似文献
89.
90.