全文获取类型
收费全文 | 1274497篇 |
免费 | 88448篇 |
国内免费 | 2065篇 |
专业分类
耳鼻咽喉 | 17212篇 |
儿科学 | 39931篇 |
妇产科学 | 32857篇 |
基础医学 | 179437篇 |
口腔科学 | 34063篇 |
临床医学 | 114511篇 |
内科学 | 245533篇 |
皮肤病学 | 27050篇 |
神经病学 | 101009篇 |
特种医学 | 49652篇 |
外国民族医学 | 215篇 |
外科学 | 194549篇 |
综合类 | 25161篇 |
现状与发展 | 3篇 |
一般理论 | 563篇 |
预防医学 | 93629篇 |
眼科学 | 28710篇 |
药学 | 99952篇 |
8篇 | |
中国医学 | 3151篇 |
肿瘤学 | 77814篇 |
出版年
2021年 | 10657篇 |
2019年 | 10910篇 |
2018年 | 14985篇 |
2017年 | 11905篇 |
2016年 | 13271篇 |
2015年 | 15063篇 |
2014年 | 20914篇 |
2013年 | 30612篇 |
2012年 | 42666篇 |
2011年 | 45617篇 |
2010年 | 26577篇 |
2009年 | 24739篇 |
2008年 | 42676篇 |
2007年 | 45621篇 |
2006年 | 45667篇 |
2005年 | 44574篇 |
2004年 | 42798篇 |
2003年 | 40778篇 |
2002年 | 39276篇 |
2001年 | 62024篇 |
2000年 | 63120篇 |
1999年 | 53077篇 |
1998年 | 15141篇 |
1997年 | 13363篇 |
1996年 | 13134篇 |
1995年 | 12215篇 |
1994年 | 11056篇 |
1993年 | 10465篇 |
1992年 | 39103篇 |
1991年 | 37533篇 |
1990年 | 36906篇 |
1989年 | 35348篇 |
1988年 | 31975篇 |
1987年 | 31058篇 |
1986年 | 29337篇 |
1985年 | 27633篇 |
1984年 | 20709篇 |
1983年 | 17591篇 |
1982年 | 10631篇 |
1981年 | 9298篇 |
1979年 | 17946篇 |
1978年 | 12434篇 |
1977年 | 11227篇 |
1976年 | 9736篇 |
1975年 | 10844篇 |
1974年 | 12420篇 |
1973年 | 11961篇 |
1972年 | 11254篇 |
1971年 | 10516篇 |
1970年 | 9648篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Pradeep Balasubramanian M.D. C. R. Srinivas M.D. Pavai Arunachalam M.S. M.Ch. K. S. Thirumurthy M.S. M.Ch. P. R. Rajkumar M.S. M.Ch. H. Manuvidhya M.B.B.S. 《Pediatric dermatology》2015,32(3):e78-e81
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique. 相似文献
32.
John Bickle 《Topics in Cognitive Science》2015,7(2):299-311
David Marr's three-level method for completely understanding a cognitive system and the importance he attaches to the computational level are so familiar as to scarcely need repeating. Fewer seem to recognize that Marr defends his famous method by criticizing the “reductionistic approach.” This sets up a more interesting relationship between Marr and reductionism than is usually acknowledged. I argue that Marr was correct in his criticism of the reductionists of his time—they were only describing (cellular activity), not explaining (cognitive functions). But a careful metascientific account of reductionistic neuroscience over the past two decades reveals that Marr's criticisms no longer have force. Contemporary neuroscience now explains cognition directly, although in a fashion—causal-mechanistically—quite different than Marr recommended. So while Marr was correct to reject the reductionism of his day and offer an alternative method for genuinely explaining cognition, contemporary cognitive scientists now owe us a new defense of Marr's famous method and the advantages of its explanations over the type now pursued successfully in current reductionist neuroscience. There are familiar reasons for thinking that this debt will not be paid easily. 相似文献
33.
34.
35.
36.
Danielle E Whittier Elizabeth J Samelson Marian T Hannan Lauren A Burt David A Hanley Emmanuel Biver Pawel Szulc Elisabeth Sornay-Rendu Blandine Merle Roland Chapurlat Eric Lespessailles Andy Kin On Wong David Goltzman Sundeep Khosla Serge Ferrari Mary L Bouxsein Douglas P Kiel Steven K Boyd 《Journal of bone and mineral research》2022,37(3):428-439
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
37.
Osric A. Forrest Daniel M. Chopyk Yael Gernez Milton R. Brown Carol K. Conrad Richard B. Moss Vin Tangpricha Limin Peng Rabindra Tirouvanziam 《Journal of cystic fibrosis》2019,18(1):64-70
Background
Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.Methods
Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.Results
Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).Conclusions
Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF. 相似文献38.
39.
40.
Xin Yi Wong Andrew Qi Jun Lim Qianyu Shen John Whay Kuang Chia Min Hoe Chew Wah Siew Tan 《Current medical research and opinion》2020,36(10):1677-1686
Abstract