全文获取类型
收费全文 | 1766篇 |
免费 | 130篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 41篇 |
妇产科学 | 40篇 |
基础医学 | 328篇 |
口腔科学 | 15篇 |
临床医学 | 169篇 |
内科学 | 320篇 |
皮肤病学 | 23篇 |
神经病学 | 86篇 |
特种医学 | 30篇 |
外科学 | 270篇 |
综合类 | 8篇 |
预防医学 | 200篇 |
眼科学 | 8篇 |
药学 | 173篇 |
中国医学 | 4篇 |
肿瘤学 | 166篇 |
出版年
2023年 | 33篇 |
2022年 | 20篇 |
2021年 | 42篇 |
2020年 | 41篇 |
2019年 | 50篇 |
2018年 | 59篇 |
2017年 | 47篇 |
2016年 | 57篇 |
2015年 | 52篇 |
2014年 | 62篇 |
2013年 | 95篇 |
2012年 | 121篇 |
2011年 | 115篇 |
2010年 | 71篇 |
2009年 | 48篇 |
2008年 | 95篇 |
2007年 | 102篇 |
2006年 | 88篇 |
2005年 | 115篇 |
2004年 | 97篇 |
2003年 | 77篇 |
2002年 | 76篇 |
2001年 | 35篇 |
2000年 | 37篇 |
1999年 | 29篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 22篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 18篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 4篇 |
1964年 | 2篇 |
排序方式: 共有1898条查询结果,搜索用时 15 毫秒
21.
Wachter DL Schlabrakowski A Hoegel J Kristiansen G Hartmann A Riener MO 《The American journal of surgical pathology》2011,35(6):873-877
The oncofetal protein, insulin-like growth factor II messenger ribonucleic acid-binding protein 3 (IMP3), has been analyzed in many different tumors. Various studies have found that IMP3 is a marker for malignancy and is correlated with increased tumor aggressiveness and reduced overall survival. The diagnosis of pancreatic ductal adenocarcinoma (PDAC) in core needle biopsies can be challenging, and immunohistochemical markers are needed. We studied IMP3 expression in 177 core needle biopsies of the pancreas, including 112 PDACs, 55 cases with chronic sclerosing pancreatitis, and 10 biopsies with tumor-free pancreatic tissue without inflammation. An additional 18 biopsies of PDAC metastases (16 liver biopsies and 2 lymph node biopsies) were analyzed. To study IMP3 expression in large tissue sections, 45 pancreatic resection specimens (26 with PDAC and 19 with chronic sclerosing pancreatitis) were investigated. In contrast to normal or inflamed pancreatic tissue, which was negative in 47 of 65 (72.3%) cases and weakly positive in 15 of 65 (23.1%) cases, strong IMP3 expression was found in 99 of 112 (88.4%) PDACs. Therefore, sensitivity and specificity of IMP3 expression in the differential diagnosis of PDAC and chronic sclerosing pancreatitis using core needle biopsies were found to be 88.4% and 94.6%, respectively. These results were confirmed in the pancreas resection specimens. Furthermore, strong IMP3 expression was found in 17 of 18 (94.4%) of the PDAC metastases that were analyzed. Our study shows that IMP3 is an easy to use and potentially new immunohistochemical marker for the diagnosis of PDAC in core needle biopsies. 相似文献
22.
Pernille Sarup Simon Metz Mariendal Petersen Niels Chr. Nielsen Volker Loeschcke Anders Malmendal 《Biogerontology》2016,17(5-6):873-882
Heat-induced hormesis, the beneficial effect of mild heat-induced stress, increases the average lifespan of many organisms. Yet little is known about the mechanisms underlying this effect. We used nuclear magnetic resonance spectroscopy to investigate the long-term effects of repeated mild heat treatments on the metabolome of male Drosophila melanogaster. 10 days after the heat treatment, metabolic aging appears to be slowed down, and a treatment response with 40 % higher levels of alanine and lactate and lower levels of aspartate and glutamate were measured. All treatment effects had disappeared 16 days later. Metabolic reprogramming has been associated with the life extending effects of dietary restriction. The metabolite changes induced by the hormetic treatment suggest that the positive effects might not be limited to the repair pathways induced, but that there also is a change in energy metabolism. A possible direct link between changes in energy metabolism and heat induced increase in Hsp70 expression is discussed. 相似文献
23.
24.
Surface‐expressed insulin receptors as well as IGF‐I receptors both contribute to the mitogenic effects of human insulin and its analogues 下载免费PDF全文
Anders Lundby Pernille Bolvig Anne Charlotte Hegelund Bo F. Hansen Jesper Worm Anne Lützen Nils Billestrup Christine Bonnesen Martin B. Oleksiewicz 《Journal of applied toxicology : JAT》2015,35(7):842-850
There is a medical need for new insulin analogues. Yet, molecular alterations to the insulin molecule can theoretically result in analogues with carcinogenic effects. Preclinical carcinogenicity risk assessment for insulin analogues rests to a large extent on mitogenicity assays in cell lines. We therefore optimized mitogenicity assay conditions for a panel of five cell lines. All cell lines expressed insulin receptors (IR), IGF‐I receptors (IGF‐IR) and hybrid receptors, and in all cell lines, insulin as well as the comparator compounds X10 and IGF‐I caused phosphorylation of the IR as well as IGF‐IR. Insulin exhibited mitogenicity EC50 values in the single‐digit nanomolar to picomolar range. We observed correlations across cell types between (i) mitogenic potency of insulin and IGF‐IR/IR ratio, (ii) Akt phosphorylation and mitogenic potency and (iii) Akt phosphorylation and IR phosphorylation. Using siRNA‐mediated knockdown of IR and IGF‐IR, we observed that in HCT 116 cells the IR appeared dominant in driving the mitogenic response to insulin, whereas in MCF7 cells the IGF‐IR appeared dominant in driving the mitogenic response to insulin. Together, our results show that the IR as well as IGF‐IR may contribute to the mitogenic potency of insulin. While insulin was a more potent mitogen than IGF‐I in cells expressing more IR than IGF‐IR, the hyper‐mitogenic insulin analogue X10 was a more potent mitogen than insulin across all cell types, supporting that the hyper‐mitogenic effect of X10 involves the IR as well as the IGF‐IR. These results are relevant for preclinical safety assessment of developmental insulin analogues. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
25.
26.
Gravholt CH Vestergaard P Hermann AP Mosekilde L Brixen K Christiansen JS 《Clinical endocrinology》2003,59(1):89-96
BACKGROUND AND OBJECTIVES: Reduced bone mineral content (BMC) and bone mineral density (BMD) have previously been reported in Turner's syndrome, although appropriate GH treatment and early induction of puberty seem to permit normal bone mass accumulation. Furthermore, an increased risk of fractures and osteoporosis have been reported in a registry study. The aim of the present study was to further characterize the risk of fractures in TS and to explore risk factors, in a historical follow-up survey based on a self-administered questionnaire. STUDY GROUPS: The questionnaire was issued to all females with TS (n = 632) in Denmark and to 1888 randomly selected controls (C) matched for age and geographical region. A total of 322 patients (51%) and 1169 controls (62%) returned the questionnaire. RESULTS: TS women were younger than C (30 years, range: 1-73 years vs. 34 years, range 2-82 years, P < 0.0005), smoked less often (17%vs. 27%, P < 0.0005), and had less frequent spontaneous menstruation (18%vs. 86%, P < 0.0005). In contrast, they used hormonal replacement therapy (HRT) more often (71%vs. 7%, P < 0.0005). The median age at start of HRT was 16 years (range 8-59 years) in TS vs. 42 years (range 12-53 years) in C (P < 0.0005). Above the age of 15 years, 83% of TS and 8% of C used HRT. GH had been used by 37% of TS but only 0.2% of C. Both type 1 and 2 diabetes were increased sevenfold among TS. Altogether, 77 individuals with TS had 109 fractures. The fracture risk was increased in TS [hazard ratio (HR, status) 1.35, confidence interval (CI) 1.04-1.75, P = 0.025]. Time to first fracture was reduced in TS (53 +/- 2 vs. 63 +/- 1; log-rank P = 0.03). Spontaneous menstruation was protective in females above 13 years of age (HR: 0.70, CI 0.54-0.93, P = 0.012). A history of parental fractures increased the risk (HR 1.92, CI 1.62-2.27, P < 0.001). Fractures of the forearm was more frequent among TS (P = 0.02). CONCLUSION: The present nationwide survey, based on questionnaires, confirms an increased risk of early fractures in TS, especially in those without ovarian function and with a positive family history of fracture and osteoporosis. It thereby emphasizes the need for being vigilant with respect to BMD measurements in these patients. 相似文献
27.
28.
Burkhard Helpap Daniel Ringli Zaki Shaikhibrahim Nicolas Wernert Glen Kristiansen 《Pathology, research and practice》2013
Prostate carcinoma (PCa) with Gleason score (GS) 7 has to be examined differentially regarding its prognosis. Using the criteria of ISUP and supplementations, we attempted to analyze the heterogeneity of PCa with GS 7 of biopsy and corresponding specimens of radical prostatectomies (RP). 相似文献
29.
Klug Tejs Ehlers Greve Thomas Andersen Camilla Hahn Pernille Danstrup Christian Petersen Niels Krintel Ninn-Pedersen Mirjana Mikkelsen Sophie Pauli Søren Fuglsang Simon Døssing Helle Christensen Anne-Louise Rusan Maria Kjeldsen Anette 《European journal of clinical microbiology & infectious diseases》2021,40(7):1461-1470
European Journal of Clinical Microbiology & Infectious Diseases - We aimed to describe the microbiology of parapharyngeal abscess (PPA) and point out the likely pathogens using the following... 相似文献