全文获取类型
收费全文 | 6164篇 |
免费 | 421篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 91篇 |
妇产科学 | 95篇 |
基础医学 | 874篇 |
口腔科学 | 95篇 |
临床医学 | 699篇 |
内科学 | 1412篇 |
皮肤病学 | 69篇 |
神经病学 | 829篇 |
特种医学 | 204篇 |
外科学 | 911篇 |
综合类 | 41篇 |
预防医学 | 358篇 |
眼科学 | 111篇 |
药学 | 444篇 |
中国医学 | 14篇 |
肿瘤学 | 340篇 |
出版年
2023年 | 24篇 |
2022年 | 51篇 |
2021年 | 137篇 |
2020年 | 75篇 |
2019年 | 123篇 |
2018年 | 170篇 |
2017年 | 107篇 |
2016年 | 109篇 |
2015年 | 135篇 |
2014年 | 185篇 |
2013年 | 275篇 |
2012年 | 439篇 |
2011年 | 457篇 |
2010年 | 260篇 |
2009年 | 247篇 |
2008年 | 410篇 |
2007年 | 423篇 |
2006年 | 421篇 |
2005年 | 423篇 |
2004年 | 381篇 |
2003年 | 355篇 |
2002年 | 335篇 |
2001年 | 84篇 |
2000年 | 73篇 |
1999年 | 78篇 |
1998年 | 82篇 |
1997年 | 76篇 |
1996年 | 50篇 |
1995年 | 59篇 |
1994年 | 48篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 30篇 |
1990年 | 33篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 21篇 |
1984年 | 23篇 |
1983年 | 15篇 |
1982年 | 25篇 |
1981年 | 19篇 |
1979年 | 16篇 |
1978年 | 19篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1975年 | 14篇 |
1974年 | 18篇 |
1973年 | 13篇 |
排序方式: 共有6613条查询结果,搜索用时 46 毫秒
1.
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
2.
3.
4.
M M Smith J E Thompson D Thomas M Castillo D Carrier S K Mukherji D Gilliam 《AJNR. American journal of neuroradiology》1997,18(2):327
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did. 相似文献
5.
Fran ois X. Roux M.D. Serge Mordon Ph.D. Catherine Fallet-Bianco M.D. Louis Merienne M.D. Bertrand C. Devaux M.D. Jean-Paul Chodkiewicz M.D. 《Surgical neurology》1990,34(6):402-407
Considering that the 1.32-μm Nd-YAG laser should have physicothermal properties close to those of the CO2 laser, a series of experiments were conducted on rat cortex (N = 51). Three laser wavelengths were compared: CO2 laser (10.6 μm), 1.06-μm Nd-YAG, and 1.32-μm Nd-YAG lasers. For each shot, temperature measurements were recorded with an infrared thermographic videocamera. The digitized signals were figured as thermal profiles and temperature developments. Ninety-five shots were correctly studied and analyzed: CO2, N = 29; 1.06-μm Nd-YAG, N = 20; 1.32-μm Nd-YAG, N = 46. The histological lesions produced by these three lasers were compared on animals killed 24 hours (N = 20), 8 days (N = 20), and 30 days (N = 5) after the laser impacts. For equivalent densities of energy, the depth of cortical necrosis was comparable for the CO2 laser (200–250 μm) and the 1.32-μm Nd-YAG laser (210–260μm) whatever the date of death; the 1.06-μm Nd-YAG laser shots were responsible for much more important damage (400–550μm). Because of its important absorption in water and nervous tissue, the authors consider the 1.32-μm Nd-YAG laser most suitable for neurosurgery, particularly because it is conducted through optic fibers, and therefore is easy to handle during neurosurgical procedures. 相似文献
6.
Efficacy of intensive multitherapy for patients with type 2 diabetes mellitus: a randomized controlled trial 总被引:1,自引:1,他引:0 下载免费PDF全文
7.
8.
Serge Lesourd 《Psycho-Oncologie》2007,1(4):222-225
Our liberal society is moving toward abolishing the boundaries between child sexuality and adult, genital sexuality, although the very existence of child sexuality incites controversy. This paper once again describes the construct of child sexuality and tries to distinguish it from adult sexuality and show how it plays a lead role in the humanisation process and in culture. 相似文献
9.
10.
Calcium release from sarcoplasmic reticulum was investigated using skinned fibers isolated from rabbit semitendinosus and psoas muscles, representative of slow and fast fibers, respectively. In both types of fibers, halothane at the concentration of 0.03% (v/v) enhanced the Ca2(+)-induced calcium release. In the absence of cytoplasmic free Ca2+, halothane induced calcium release in a dose-dependent manner, with a similar sensitivity for both semitendinosus and psoas fibers. These results are discussed in connection with muscular diseases such as malignant hyperthermia in which the crisis is triggered during anesthesia by halothane. 相似文献