首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9646篇
  免费   813篇
  国内免费   577篇
耳鼻咽喉   78篇
儿科学   91篇
妇产科学   89篇
基础医学   1111篇
口腔科学   156篇
临床医学   1192篇
内科学   1468篇
皮肤病学   216篇
神经病学   509篇
特种医学   319篇
外国民族医学   3篇
外科学   950篇
综合类   1487篇
现状与发展   3篇
一般理论   1篇
预防医学   618篇
眼科学   277篇
药学   1000篇
  4篇
中国医学   452篇
肿瘤学   1012篇
  2025年   2篇
  2024年   119篇
  2023年   186篇
  2022年   357篇
  2021年   462篇
  2020年   344篇
  2019年   301篇
  2018年   309篇
  2017年   295篇
  2016年   293篇
  2015年   423篇
  2014年   495篇
  2013年   485篇
  2012年   716篇
  2011年   740篇
  2010年   470篇
  2009年   396篇
  2008年   476篇
  2007年   546篇
  2006年   450篇
  2005年   439篇
  2004年   433篇
  2003年   416篇
  2002年   373篇
  2001年   325篇
  2000年   220篇
  1999年   203篇
  1998年   105篇
  1997年   95篇
  1996年   93篇
  1995年   71篇
  1994年   84篇
  1993年   44篇
  1992年   53篇
  1991年   42篇
  1990年   24篇
  1989年   28篇
  1988年   26篇
  1987年   26篇
  1986年   20篇
  1985年   14篇
  1984年   8篇
  1983年   8篇
  1982年   3篇
  1981年   3篇
  1980年   2篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1964年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Purpose: The purpose of this study was to determine intertester and intratester reliability of ultrasound measurements of bilateral diaphragm excursions in the thoracic and thoracolumbar spinal curves of 31 females with adolescent idiopathic scoliosis (AIS) (mean age = 14.1 ± 1.8 years). Method: Subjects were tested during tidal breathing using real-time ultrasound imaging with a 3.5 MHz curvilinear transducer. Results: There were no significant differences in intratester and intertester reliability values in bilateral diaphragmatic excursions measured at the thoracolumbar spinal curve, whereas significant differences were observed in measurements taken at the thoracic spinal curve (p < 0.05). Overall, the intertester and intratester reliabilities of the thoracic and thoracolumbar curves in AIS ranged from 0.764 to 0.998. Conclusions: These findings suggest that ultrasound imaging is highly reliable between and within testers and is useful to precisely discriminate pathological diaphragm movement in idiopathic thoracic scoliosis and idiopathic thoracolumbar scoliosis.  相似文献   
42.
BackgroundStudies on how the coronavirus pandemic has affected pediatric inflammatory bowel disease (PIBD) are lacking. We aimed to investigate the trends in epidemiology, characteristics, initial management, and short-term outcomes of PIBD in South Korea over the recent three years including the era of coronavirus disease 2019 (COVID-19).MethodsThis multicenter study retrospectively investigated temporal trends in the epidemiology of PIBD in Korea. Annual occurrences, disease phenotypes, and initial management at diagnosis were analyzed from January 2018 to June 2021.ResultsA total of 486 patients from 17 institutions were included in this epidemiological evaluation. Analysis of the occurrence trend confirmed a significant increase in PIBD, regardless of the COVID-19 pandemic. In Crohn’s disease, patients with post-coronavirus outbreaks had significantly higher fecal calprotectin levels than those with previous onset (1,339.4 ± 717.04 vs. 1,595.5 ± 703.94, P = 0.001). Patients with post-coronavirus-onset ulcerative colitis had significantly higher Pediatric Ulcerative Colitis Activity Index scores than those with previous outbreaks (48 ± 17 vs. 36 ± 15, P = 0.004). In the initial treatment of Crohn’s disease, the use of 5-aminosalicylic acid (5-ASA) and steroids significantly decreased (P = 0.006 and 0.001, respectively), and enteral nutrition and the use of infliximab increased significantly (P = 0.045 and 0.009, respectively). There was a significant increase in azathioprine use during the initial treatment of ulcerative colitis (P = 0.020).ConclusionRegardless of the COVID-19 pandemic, the number of patients with PIBD is increasing significantly annually in Korea. The initial management trends for PIBD have also changed. More research is needed to establish appropriate treatment guidelines considering the epidemiological and clinical characteristics of Korean PIBD.  相似文献   
43.
目的 探讨极低/超低出生体质量儿并发晚发型败血症死亡的高危因素.方法 选取2016年9月—2019年12月收治的血培养确诊晚发型败血症的极低/超低出生体质量儿,分析临床资料,找出死亡相关及独立危险因素.结果 538例极低/超低出生体质量儿发生晚发型败血症66例,发病率12.27%,死亡15例,病死率22.73%.胎龄小...  相似文献   
44.
Epoxy asphalt concrete (EAC) has excellent properties such as high strength, outstanding thermal stability, and great fatigue resistance, and is considered to be a long-life pavement material. Meanwhile, the low initial viscosity of the epoxy components provides the possibility to reduce the mixing temperature of SBS-modified asphalt. The purpose of this study is to verify the feasibility of low-emission mixing of SBS-modified epoxy asphalt and to compare the mechanical responses in several typical structures with EAC, in order to perform structure optimization for practical applications of EAC. In this paper, the Brookfield rotational viscosity test was conducted to investigate the feasibility of mixing SBS-modified epoxy asphalt at a reduced temperature. Subsequently, the dynamic modulus tests were carried out on EAC to obtain the Prony series in order to provide viscoelastic parameters for the finite element model. Six feasible pavement structures with EAC were proposed, and a finite element method (FEM) model was developed to analyze and compare the mechanical responses with the conventional pavement structure. Additionally, the design life was predicted and compared to comprehensively evaluate the performance of EAC structures. Finally, life cycle assessment (LCA) on carbon emissions was developed to explore the emission reduction effect of the epoxy asphalt pavement. The results indicate that the addition of epoxy components could reduce the mixing temperature of SBS-modified asphalt by 30 °C. The proper use of EAC can significantly improve the mechanical condition of the pavement and improve its performance and service life. It is recommended to choose S5 (with EAC applied in the middle-lower layer) as the optimal pavement structure, whose allowable load repetitions to limit fatigue cracking were more than 1.7 times that of conventional pavements and it has favorable rutting resistance as well. The LCA results show that in a 25-year life cycle, the carbon emissions of epoxy asphalt pavements could be reduced by 29.8% in comparison to conventional pavements.  相似文献   
45.
The clinical course and prognosis of patients with elderly-onset Crohn’s disease (CD) remain unclear. This study aimed to analyze the clinical characteristics and outcomes of elderly-onset CD patients from the prospective CONNECT study cohort, a nationwide, multicenter cohort study of patients with CD in Korea. Among a total of 1,175 patients in the prospective CONNECT study cohort, 94 patients (Montreal age A3) were included and divided into two groups according to their age at diagnosis: the elderly-onset group (diagnosed with CD after 60 years of age, n=26, 67.54±6.7 years) and late adult-onset group (diagnosed as CD at age 41 to 59 years, n=68, 48.06±5.1 years). The elderly-onset group was characterized by a lower Crohn’s disease activity index at diagnosis (124.89±101.9 vs 189.55±128.6, p=0.023) and higher rates of previous anti-tuberculosis treatment (34.6% vs 4.4%, p<0.001) than the late adult-onset group. Compared with the late adult-onset group, the elderly-onset group showed a significantly less use of thiopurines (p=0.003), as well as anti-tumor necrosis factor-alpha agents (p=0.047). Additionally, the elderly-onset group was less likely to require bowel resection than the late adult-onset group (p=0.067), suggesting that elderly-onset CD patients in Korea appear to have more favorable clinical outcomes than late adult-onset CD patients. (Gut Liver 2022;16:-1000)  相似文献   
46.
47.
48.
ObjectiveThis study is aimed to investigate whether both pre‐operative full‐spine 3Dimensional computed tomography scan (3D CT) and X‐ray film were necessary for patients with severe ankylosing spondylitis (AS) kyphosis deformity.MethodsThe research objects were selected from the inpatients with AS in our hospital from 2017 to 2019. A total of 42 patients were included in the study. On both the synthesized 2Dimensional (2D) lateral radiograph and X‐ray film, the globe kyphosis (GK), the lumber lordosis (LL), the thoracolumbar kyphosis (TLK) and the thoracic kyphosis (TK) were measured. And the angle seventh thoracic vertebra (T7), the angle twelfth thoracic vertebra (T12) and the angle third lumber vertebra (L3) were also measured. Two researchers with professional medical education were randomly selected to perform the measurement method and record the measurement data. Two researchers independently completed, recorded, and evaluated the accuracy and consistency of the measurement data. This study used intraclass correlation coefficient (ICC) to analyze the synthesized 2D lateral radiograph and general X‐ray film of 42 subjects by two researchers, in order to evaluate the consistency of data measurement results between the examiners. Through the comparison of the above parameters that the GK, LL, TLK, TK, angle T7, angle T12 and angle L3, the evaluation was made both pre‐operative full‐spine 3D CT and X‐ray film were necessary for patients with severe AS kyphosis deformity.ResultsThere was no significant difference between the GK, LL, TLK, TK, angle T7, angle T12, angle L3 on the synthesized 2D lateral radiograph and that on X‐ray film (P = 0.240, 0.324, 0.199, 0.095, 0.421, 0.087, 0.478). Agreement two researchers was excellent with ICC of the GK, LL, TLK, TK, angle T7, angle T12, angle L3 (0.977, 0.969, 0.986, 0.945, 0.947, 0.915, 0.857) on the synthesized 2D lateral radiograph. The Bland–Altman plot results that the measurement results of examiners are reliable and stable.ConclusionBy estimating the degree of spinal sagittal imbalance and measuring the Cobb angle, we can see that full‐length spine radiographs of the patients are unnecessary for patients with severe AS kyphosis deformity who will or have undergone preoperative spine 3D CT.  相似文献   
49.
Cholesterol is an essential substance to maintain cell membranes. Low levels of total cholesterol (TC) are associated with poor prognosis in critically ill patients. Cardiac arrest-induced whole-body ischemia and reperfusion injury cause a sepsis-like syndrome. The Cholesterol level in post-cardiac arrest patients may indicate the degree of endotoxemia or inflammation caused by ischemic and reperfusion injury. We aimed to investigate the association of TC levels with neurologic outcome of out-of-hospital cardiac arrest (OHCA) survivors who underwent target temperature management (TTM). This was a retrospective single-center observational study from May 2018 to April 2021 on a cohort of 106 patients. TC levels were determined in samples obtained immediately and at 24, 48, and 72 hours after the return of spontaneous circulation (ROSC). The primary outcome was poor neurologic outcome at 3 months after ROSC. Poor neurologic outcome was defined by cerebral performance categories 3 to 5. Sixty patients had a poor neurologic outcome. TC levels were significantly lower in the poor neurologic outcome group at each time point. The TC levels for predicting poor neurologic outcome had a sensitivity of 80.8%, with 67.6% specificity at 48 hours (TC48) after ROSC. The areas under the curve value of TC48 was 0.771 (0.670–0.853), with a cutoff value of 114 mg/dL. TC level at 48 hours after ROSC was a helpful marker for the 3-month poor neurologic outcome. This might be an easily accessible predictive marker of neurologic outcome in OHCA survivors treated with TTM.  相似文献   
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号