全文获取类型
收费全文 | 1911055篇 |
免费 | 339592篇 |
国内免费 | 40362篇 |
专业分类
耳鼻咽喉 | 23363篇 |
儿科学 | 58933篇 |
妇产科学 | 47834篇 |
基础医学 | 307293篇 |
口腔科学 | 50542篇 |
临床医学 | 199561篇 |
内科学 | 404950篇 |
皮肤病学 | 42148篇 |
神经病学 | 149749篇 |
特种医学 | 71748篇 |
外国民族医学 | 242篇 |
外科学 | 291527篇 |
综合类 | 87720篇 |
现状与发展 | 4篇 |
一般理论 | 532篇 |
预防医学 | 158727篇 |
眼科学 | 56614篇 |
药学 | 176108篇 |
10篇 | |
中国医学 | 51124篇 |
肿瘤学 | 112280篇 |
出版年
2019年 | 26606篇 |
2018年 | 33501篇 |
2017年 | 29448篇 |
2016年 | 29412篇 |
2015年 | 31587篇 |
2014年 | 38551篇 |
2013年 | 50084篇 |
2012年 | 64467篇 |
2011年 | 68588篇 |
2010年 | 48363篇 |
2009年 | 52422篇 |
2008年 | 62471篇 |
2007年 | 62515篇 |
2006年 | 62334篇 |
2005年 | 59640篇 |
2004年 | 59824篇 |
2003年 | 56559篇 |
2002年 | 54850篇 |
2001年 | 101585篇 |
2000年 | 99607篇 |
1999年 | 87062篇 |
1998年 | 30578篇 |
1997年 | 27310篇 |
1996年 | 27672篇 |
1995年 | 27302篇 |
1994年 | 25696篇 |
1993年 | 23562篇 |
1992年 | 66457篇 |
1991年 | 63994篇 |
1990年 | 60998篇 |
1989年 | 58753篇 |
1988年 | 53960篇 |
1987年 | 52185篇 |
1986年 | 49091篇 |
1985年 | 46116篇 |
1984年 | 34134篇 |
1983年 | 29698篇 |
1982年 | 19616篇 |
1981年 | 17738篇 |
1980年 | 16337篇 |
1979年 | 30564篇 |
1978年 | 22055篇 |
1977年 | 19657篇 |
1976年 | 18272篇 |
1975年 | 18807篇 |
1974年 | 21825篇 |
1973年 | 20838篇 |
1972年 | 19610篇 |
1971年 | 17809篇 |
1970年 | 16641篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Jenny U. Johansson Nathaniel S. Woodling Qian Wang Maharshi Panchal Xibin Liang Angel Trueba-Saiz Holden D. Brown Siddhita D. Mhatre Taylor Loui Katrin I. Andreasson 《The Journal of clinical investigation》2015,125(1):350-364
Microglia, the innate immune cells of the CNS, perform critical inflammatory and noninflammatory functions that maintain normal neural function. For example, microglia clear misfolded proteins, elaborate trophic factors, and regulate and terminate toxic inflammation. In Alzheimer’s disease (AD), however, beneficial microglial functions become impaired, accelerating synaptic and neuronal loss. Better understanding of the molecular mechanisms that contribute to microglial dysfunction is an important objective for identifying potential strategies to delay progression to AD. The inflammatory cyclooxygenase/prostaglandin E2 (COX/PGE2) pathway has been implicated in preclinical AD development, both in human epidemiology studies and in transgenic rodent models of AD. Here, we evaluated murine models that recapitulate microglial responses to Aβ peptides and determined that microglia-specific deletion of the gene encoding the PGE2 receptor EP2 restores microglial chemotaxis and Aβ clearance, suppresses toxic inflammation, increases cytoprotective insulin-like growth factor 1 (IGF1) signaling, and prevents synaptic injury and memory deficits. Our findings indicate that EP2 signaling suppresses beneficial microglia functions that falter during AD development and suggest that inhibition of the COX/PGE2/EP2 immune pathway has potential as a strategy to restore healthy microglial function and prevent progression to AD. 相似文献
92.
93.
94.
95.
Implications for Practice
Breast cancer is far more curable than in the past but requires multimodality treatment. Great care must be taken to use the least leukemogenic treatment programs that do not sacrifice efficacy. Elimination of radiation and anthracycline/alkylating agent regimens will be helpful where possible, particularly in younger patients and possibly those with homologous repair deficiency (HRD). Use of colony-stimulating factors should be limited to those who truly require them for safe chemotherapy administration. Further study of a possible leukemogenic association with HRD and the various forms of colony-stimulating factors is badly needed.96.
97.
98.
Parallel enzyme‐linked immunosorbent assay screening for human immunodeficiency virus among blood donors in five Chinese blood centres: a retrospective analysis 下载免费PDF全文
99.
Kui Li Jiawen Wang Shengxiong Liu Sen Su Chenjian Feng Xiaoxiang Fan Zhiyong Yin 《中华创伤杂志(英文版)》2015,18(2):65-73
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.
Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.
Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.
Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism. 相似文献
100.
Nirmanmoh Bhatia Buddhadeb Dawn Tariq S. Siddiqui Marcus F. Stoddard 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(1):16-24
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index. 相似文献