全文获取类型
收费全文 | 2106篇 |
免费 | 137篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 171篇 |
妇产科学 | 26篇 |
基础医学 | 239篇 |
口腔科学 | 58篇 |
临床医学 | 317篇 |
内科学 | 523篇 |
皮肤病学 | 73篇 |
神经病学 | 61篇 |
特种医学 | 392篇 |
外科学 | 102篇 |
综合类 | 45篇 |
预防医学 | 96篇 |
眼科学 | 19篇 |
药学 | 84篇 |
2篇 | |
肿瘤学 | 109篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 33篇 |
2017年 | 23篇 |
2016年 | 23篇 |
2015年 | 42篇 |
2014年 | 49篇 |
2013年 | 61篇 |
2012年 | 41篇 |
2011年 | 44篇 |
2010年 | 94篇 |
2009年 | 95篇 |
2008年 | 54篇 |
2007年 | 101篇 |
2006年 | 62篇 |
2005年 | 63篇 |
2004年 | 33篇 |
2003年 | 22篇 |
2002年 | 31篇 |
2001年 | 37篇 |
2000年 | 37篇 |
1999年 | 35篇 |
1998年 | 130篇 |
1997年 | 156篇 |
1996年 | 133篇 |
1995年 | 109篇 |
1994年 | 115篇 |
1993年 | 98篇 |
1992年 | 31篇 |
1991年 | 39篇 |
1990年 | 39篇 |
1989年 | 56篇 |
1988年 | 48篇 |
1987年 | 42篇 |
1986年 | 49篇 |
1985年 | 45篇 |
1984年 | 28篇 |
1983年 | 15篇 |
1982年 | 24篇 |
1981年 | 29篇 |
1980年 | 25篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 14篇 |
1966年 | 1篇 |
排序方式: 共有2319条查询结果,搜索用时 12 毫秒
61.
Adrian B Levine Jason Peng David Farnell Mitchell Nursey Yiping Wang Julia R Naso Hezhen Ren Hossein Farahani Colin Chen Derek Chiu Aline Talhouk Brandon Sheffield Maziar Riazy Philip P Ip Carlos Parra-Herran Anne Mills Naveena Singh Basile Tessier-Cloutier Taylor Salisbury Jonathan Lee Tim Salcudean Steven JM Jones David G Huntsman C Blake Gilks Stephen Yip Ali Bashashati 《The Journal of pathology》2020,252(2):178-188
Deep learning-based computer vision methods have recently made remarkable breakthroughs in the analysis and classification of cancer pathology images. However, there has been relatively little investigation of the utility of deep neural networks to synthesize medical images. In this study, we evaluated the efficacy of generative adversarial networks to synthesize high-resolution pathology images of 10 histological types of cancer, including five cancer types from The Cancer Genome Atlas and the five major histological subtypes of ovarian carcinoma. The quality of these images was assessed using a comprehensive survey of board-certified pathologists (n = 9) and pathology trainees (n = 6). Our results show that the real and synthetic images are classified by histotype with comparable accuracies and the synthetic images are visually indistinguishable from real images. Furthermore, we trained deep convolutional neural networks to diagnose the different cancer types and determined that the synthetic images perform as well as additional real images when used to supplement a small training set. These findings have important applications in proficiency testing of medical practitioners and quality assurance in clinical laboratories. Furthermore, training of computer-aided diagnostic systems can benefit from synthetic images where labeled datasets are limited (e.g. rare cancers). We have created a publicly available website where clinicians and researchers can attempt questions from the image survey ( http://gan.aimlab.ca/ ). © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
62.
DL?MagerEmail author AD?Haffajee PM?Devlin CM?Norris MR?Posner JM?Goodson 《Journal of translational medicine》2005,3(1):27
Background
The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls. 相似文献63.
JM Hopkin 《Current opinion in immunology》1997,9(6):788-792
Atopy — a T helper 2 cell driven hypersensitivity to innocuous antigens (allergens) which causes most cases of asthma — is of complex genetic and environmental origins. There is compelling epidemiological evidence for a rise in atopic disease in ‘westernised’ communities. The changing pattern of microbial exposure in early childhood is suggested to be the principal candidate mechanism for this rise. 相似文献
64.
The bias favoring deletion over inversion in DH-JH rearrangement has been
known for years, but the underlying mechanism has yet to be fully defined.
It has been suggested that the ratio of deletion/inversion is determined by
the combined effect of two factors: (i) the relative strengths of 5' and 3'
recombination signal sequences (RSS) of a DH segment, and (ii) the
efficiency with which the deletional product (one joint) forms relative to
the inversional product (two joints). In this study, we analyzed for the
first time the effect of factor 1 alone on the biased 3' RSS utilization in
DH-JH joining by using deletional plasmids in an extrachromosomal substrate
V(D)J recombination assay. It was found that the 3' RSS and associated
coding end (12 bp) mediate recombination more efficiently than the 5'
RSS/coding end DH-JH plasmids. These results demonstrate that the effect of
the RSS/coding end alone can account, at least partially, for the
predominant deletion in DH-JH recombination. The potential effect of the
relative strength of RSS and associated coding end on the ordered
rearrangement of DH-JH followed by VH to DH-JH was also assessed. When
recombination frequencies of D-->J (3' DH to J3) were compared with
frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found
that V-->D joining was, if anything, more efficient than D-->J
joining. Therefore, if all three segments were accessible, RSS/coding end
effects would not contribute to the ordered rearrangement of the IgH locus.
相似文献
65.
66.
Eric Gomez Charles Cazanave Scott A. Cunningham Kerryl E. Greenwood-Quaintance James M. Steckelberg James R. Uhl Arlen D. Hanssen Melissa J. Karau Suzannah M. Schmidt Douglas R. Osmon Elie F. Berbari Jayawant Mandrekar Robin Patel 《Journal of clinical microbiology》2012,50(11):3501-3508
Periprosthetic tissue and/or synovial fluid PCR has been previously studied for prosthetic joint infection (PJI) diagnosis; however, few studies have assessed the utility of PCR on biofilms dislodged from the surface of explanted arthroplasties using vortexing and sonication (i.e., sonicate fluid PCR). We compared sonicate fluid 16S rRNA gene real-time PCR and sequencing to culture of synovial fluid, tissue, and sonicate fluid for the microbiologic diagnosis of PJI. PCR sequences generating mixed chromatograms were decatenated using RipSeq Mixed. We studied sonicate fluids from 135 and 231 subjects with PJI and aseptic failure, respectively. Synovial fluid, tissue, and sonicate fluid culture and sonicate fluid PCR had similar sensitivities (64.7, 70.4, 72.6, and 70.4%, respectively; P > 0.05) and specificities (96.9, 98.7, 98.3, and 97.8%, respectively; P > 0.05). Combining sonicate fluid culture and PCR, the sensitivity was higher (78.5%, P < 0.05) than those of individual tests, with similar specificity (97.0%). Thirteen subjects had positive sonicate fluid culture but negative PCR, and 11 had negative sonicate fluid culture but positive PCR (among which 7 had prior use of antimicrobials). Broad-range PCR and culture of sonicate fluid have equivalent performance for PJI diagnosis. 相似文献
67.
68.
Jolanda MA Boer Jan Albert Kuivenhoven Edith JM Feskens Evert G Schouten Louis M Havekes Jacob C Seidell John JP Kastelein Daan Kromhout 《Clinical genetics》1999,56(2):158-163
We investigated interactions between a mutation (D9N) in the lipoprotein lipase (LPL) gene and physical activity, as well as other lifestyle factors, on lipid traits in a population-based sample of Dutch men and women (n = 379). We used questionnaire information to classify physical activity, alcohol consumption, and smoking habits, while overweight was defined as a body mass index (BMI) > 25 kg/m2. Non-fasting blood samples were used for the determination of lipid traits and the D9N genotype. Fifteen subjects (4%) carried the mutation. They presented with higher levels of total cholesterol, apolipoprotein (apo) B and triglycerides compared to non-carriers. While no interactions with overweight, alcohol consumption, and smoking were found, a strong interaction between the D9N mutation and physical activity became apparent. Physically inactive D9N carriers (n = 5) had considerably higher total cholesterol (+2 mmol/l, p < or = 0.0001) and apo B levels (+63 mg/dl, p < or = 0.0001) compared to non-carriers of this mutation, whereas their high-density lipoprotein (HDL)-cholesterol concentrations were lower (-0.22 mmol/l, p < 0.05). This was not the case for physically active D9N carriers (n = 10). In conclusion, a common variant of the LPL gene (D9N) adversely affects plasma lipid and lipoprotein profiles. However, the unfavorable consequences may be counteracted by physical activity. 相似文献
69.
JM Kanyamurwa S Wamala R Baryamutuma E Kabwama R Loewenson 《African health sciences》2013,13(3):829-841
Background
Globalization-related measures to liberalize trade and stimulate export production were applied in Uganda in the late 1980s, including in the coffee production sector, to revitalize agricultural production, increase incomes to farmers and improve rural food security.Objective
To explore the different effects of such measures on the health and dietary outcomes of female coffee and food small holder farmers in Uganda.Methods
We gathered evidence through a cross-sectional comparative interview survey of 190 female coffee producers and 191 female food producers in Ntungamo district. The study mostly employed quantitative methods of data collection, targeting the sampled households. We also utilized qualitative data; collected three months after the household survey data had been collected and their analysis had been accomplished. Using qualitative interviews based on an unstructured interview guide, extra qualitative information was collected from key informants at national, district and community levels. This was among other underlying principles to avoid relying on snapshot information earlier collected at household level in order to draw valid and compelling conclusions from the study. We used indicators of production, income, access to food and dietary patterns, women''s health and health care. Of the two groups selected from the same area, female coffee producers represented a higher level of integration into liberalised export markets.Results
Document review suggests that, although Uganda''s economy grew in the period, the household economic and social gains after the liberalization measures may have been less than expected. In the survey carried out, both food and coffee producers were similarly poor, involved in small-scale production, and of a similar age and education level. Coffee producers had greater land and livestock ownership, greater access to inputs and higher levels of income and used a wider variety of markets than food producers, but they had to work longer hours to obtain these economic returns, and spent more cash on health care and food from commercial sources. Their health outcomes were similar to those of the food producers, but with poorer dietary outcomes and greater food stress.Conclusions
The small-scale women farmers who are producing food cannot rely on the economic infrastructure to give them support for meaningful levels of production. However, despite having higher incomes than their food producing counterparts, the evidence showed that women who are producing coffee in Uganda as an export commodity cannot rely on the income from their crops to guarantee their health and nutritional wellbeing, and that the income advantage gained in coffee-producing households has not translated into consistently better health or food security outcomes. Both groups have limited levels of autonomy and control to address these problems. 相似文献70.