全文获取类型
收费全文 | 1587篇 |
免费 | 72篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 62篇 |
妇产科学 | 33篇 |
基础医学 | 186篇 |
口腔科学 | 35篇 |
临床医学 | 169篇 |
内科学 | 330篇 |
皮肤病学 | 47篇 |
神经病学 | 182篇 |
特种医学 | 166篇 |
外科学 | 132篇 |
综合类 | 28篇 |
一般理论 | 4篇 |
预防医学 | 98篇 |
眼科学 | 37篇 |
药学 | 80篇 |
1篇 | |
肿瘤学 | 62篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 28篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 48篇 |
2012年 | 72篇 |
2011年 | 81篇 |
2010年 | 63篇 |
2009年 | 47篇 |
2008年 | 71篇 |
2007年 | 96篇 |
2006年 | 69篇 |
2005年 | 80篇 |
2004年 | 56篇 |
2003年 | 46篇 |
2002年 | 42篇 |
2001年 | 30篇 |
2000年 | 31篇 |
1999年 | 34篇 |
1998年 | 47篇 |
1997年 | 53篇 |
1996年 | 47篇 |
1995年 | 29篇 |
1994年 | 34篇 |
1993年 | 33篇 |
1992年 | 27篇 |
1991年 | 28篇 |
1990年 | 32篇 |
1989年 | 41篇 |
1988年 | 38篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 25篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 10篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1972年 | 7篇 |
1971年 | 8篇 |
1969年 | 5篇 |
排序方式: 共有1667条查询结果,搜索用时 15 毫秒
41.
42.
43.
Busch MP; Laycock M; Kleinman SH; Wages JW Jr; Calabro M; Kaplan JE; Khabbaz RF; Hollingsworth CG 《Blood》1994,83(4):1143-1148
Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II. 相似文献
44.
作为标准化的非手术治疗,诱导化疗(ICT)在治疗局部晚期头颈鳞癌已有几十年的历史,但是关于其作用尚存争议。同期放化疗(CRT)是目前标准化的非手术治疗,然而由于ICT能够使肿瘤体积缩小,提高放疗的可行性,改善患者对放疗的耐受力,增加放疗后器官功能保留的可能性及降低远处转移率。所以,对ICT的研究从未停止。该文对近期随机试验进行回顾分析,与手术或单独CRT比较,评估ICT中紫杉醇的价值。Meta分析比较ICT中紫杉醇和顺铂及5氟尿嘧啶的作用。之前的随机试验中,并没有ICT提高生存率的报道。但 相似文献
45.
Jared MP Bullard Arshad N Ahsanuddin Anamarija M Perry L Robbin Lindsay Mahmood Iranpour Antonia Dibernardo Paul G Van Caeseele 《The Canadian Journal of Infectious Diseases & Medical Microbiology》2014,25(6):e87-e89
A child with a complicated medical history that included asplenia acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba. Although the clinical findings were subtle, astute laboratory work helped to reach a preliminary identification of Babesia species, while reference laboratory testing confirmed the diagnosis. Blacklegged ticks (Ixodes scapularis) are known to transmit Borrelia burgdorferi and Anaplasma phagocytophilum in the province; however, the present case represents the first known instance of tick-borne B microti, both in Manitoba and in Canada. The expanding territory of the blacklegged tick increases the relevance of this emerging infection. Clinicians, laboratory medical practitioners and public health officials should be aware of B microti as a potential locally acquired infection in Canada. 相似文献
46.
RP Berntsson J Ter Beek M Majsnerowska RH Duurkens P Puri B Poolman DJ Slotboom 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(35):13990-13995
Energy coupling factor (ECF) proteins are ATP-binding cassette transporters involved in the import of micronutrients in prokaryotes. They consist of two nucleotide-binding subunits and the integral membrane subunit EcfT, which together form the ECF module and a second integral membrane subunit that captures the substrate (the S component). Different S components, unrelated in sequence and specific for different ligands, can interact with the same ECF module. Here, we present a high-resolution crystal structure at 2.1 Å of the biotin-specific S component BioY from Lactococcus lactis. BioY shares only 16% sequence identity with the thiamin-specific S component ThiT from the same organism, of which we recently solved a crystal structure. Consistent with the lack of sequence similarity, BioY and ThiT display large structural differences (rmsd = 5.1 Å), but the divergence is not equally distributed over the molecules: The S components contain a structurally conserved N-terminal domain that is involved in the interaction with the ECF module and a highly divergent C-terminal domain that binds the substrate. The domain structure explains how the S components with large overall structural differences can interact with the same ECF module while at the same time specifically bind very different substrates with subnanomolar affinity. Solitary BioY (in the absence of the ECF module) is monomeric in detergent solution and binds D-biotin with a high affinity but does not transport the substrate across the membrane. 相似文献
47.
Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries. 相似文献
48.
49.
Mickael Dinomais Eva Chinier Gregoire Lignon Isabelle Richard Aram Ter Minassian Sylvie Nguyen The Tich 《Research in developmental disabilities》2013,34(10):3487-3496
In patients with cerebral palsy (CP), neuroimaging studies have demonstrated that passive movement and action–observation tasks have in common to share neuronal activation in all or part of areas involved in motor system. Action observation with simultaneous congruent passive movements may have additional effects in the recruitment of brain motor areas. The aim of this functional magnetic resonance imaging (fMRI) study was to examine brain activation in patients with unilateral CP during passive movement with and without simultaneous observation of simple hand movement. Eighteen patients with unilateral CP (fourteen male, mean age 14 years and 2 months) participated in the study. Using fMRI block design, brain activation following passive simple opening–closing hand movement of either the paretic or nonparetic hand with and without simultaneous observation of a similar movement performed by either the left or right hand of an actor was compared. Passive movement of the paretic hand performed simultaneously to the observation of congruent movement activated more “higher motor areas” including contralesional pre-supplementary motor area, superior frontal gyrus (extending to premotor cortex), and superior and inferior parietal regions than nonvideo-guided passive movement of the paretic hand. Passive movement of the paretic hand recruited more ipsilesional sensorimotor areas compared to passive movement of the nonparetic hand. Our study showed that the combination of observation of congruent hand movement simultaneously to passive movement of the paretic hand recruits more motor areas, giving neuronal substrate to propose video-guided passive movement of paretic hand in CP rehabilitation. 相似文献
50.
Aram Ter Minassian Emmanuel Ricalens Stanislas Humbert Flavie Duc Christophe Aubé Laurent Beydon 《Human brain mapping》2013,34(9):2228-2243
Few studies have explored the effect of acute pain on attentional networks and on the default mode network. Moreover, these studies convey conflicting results, seemingly caused by design. To reassess this issue, we studied 20 healthy subjects with functional magnetic resonance imaging while delivering painful electric shocks. The design was purposely constructed to separate rest, anticipation, and pain perception. We found that default mode network activity in response to pain was biphasic. It deactivated during anticipation when the dorsal attentional network was activated. During pain perception, the default mode network was activated, as were attentional networks. The left posterior fusiform gyrus showed the same dynamics as the default mode network, and its activity was negatively correlated to the subject's pain intensity rating. The associative pregenual anterior cingulate cortex seemed to play a key role in these coactivations. These results concur with data from the literature showing that enhanced pain perception results in greater default mode network activity and that the anticorrelation between the default mode network and the dorsal attentional network disappears in chronic pain patients. Hum Brain Mapp 34:2228–2243, 2013. © 2012 Wiley Periodicals, Inc. 相似文献