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   164455篇
  免费   11065篇
  国内免费   1253篇
耳鼻咽喉   2323篇
儿科学   3101篇
妇产科学   3794篇
基础医学   24622篇
口腔科学   3391篇
临床医学   15616篇
内科学   31177篇
皮肤病学   4637篇
神经病学   12354篇
特种医学   8372篇
外科学   22292篇
综合类   2164篇
现状与发展   5篇
一般理论   81篇
预防医学   9827篇
眼科学   4406篇
药学   14061篇
中国医学   1662篇
肿瘤学   12888篇
  2023年   783篇
  2022年   2267篇
  2021年   5021篇
  2020年   2583篇
  2019年   3714篇
  2018年   4557篇
  2017年   3401篇
  2016年   4399篇
  2015年   5916篇
  2014年   7218篇
  2013年   8702篇
  2012年   13124篇
  2011年   12698篇
  2010年   7511篇
  2009年   6306篇
  2008年   9514篇
  2007年   9323篇
  2006年   8554篇
  2005年   8157篇
  2004年   7245篇
  2003年   6288篇
  2002年   5457篇
  2001年   4395篇
  2000年   4046篇
  1999年   3276篇
  1998年   1319篇
  1997年   998篇
  1996年   956篇
  1995年   868篇
  1994年   753篇
  1993年   646篇
  1992年   1574篇
  1991年   1572篇
  1990年   1358篇
  1989年   1243篇
  1988年   1158篇
  1987年   1033篇
  1986年   1010篇
  1985年   887篇
  1984年   645篇
  1983年   563篇
  1982年   399篇
  1981年   378篇
  1980年   338篇
  1979年   521篇
  1978年   406篇
  1977年   388篇
  1976年   343篇
  1974年   358篇
  1973年   327篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
ObjectiveTo compare the lumen parameters measured by the location-adaptive threshold method (LATM), in which the inter- and intra-scan attenuation variabilities of coronary computed tomographic angiography (CCTA) were corrected, and the scan-adaptive threshold method (SATM), in which only the inter-scan variability was corrected, with the reference standard measurement by intravascular ultrasonography (IVUS).Materials and MethodsThe Hounsfield unit (HU) values of whole voxels and the centerline in each of the cross-sections of the 22 target coronary artery segments were obtained from 15 patients between March 2009 and June 2010, in addition to the corresponding voxel size. Lumen volume was calculated mathematically as the voxel volume multiplied by the number of voxels with HU within a given range, defined as the lumen for each method, and compared with the IVUS-derived reference standard. Subgroup analysis of the lumen area was performed to investigate the effect of lumen size on the studied methods. Bland-Altman plots were used to evaluate the agreement between the measurements.ResultsLumen volumes measured by SATM was significantly smaller than that measured by IVUS (mean difference, 14.6 mm3; 95% confidence interval [CI], 4.9–24.3 mm3); the lumen volumes measured by LATM and IVUS were not significantly different (mean difference, −0.7 mm3; 95% CI, −9.1–7.7 mm3). The lumen area measured by SATM was significantly smaller than that measured by LATM in the smaller lumen area group (mean of difference, 1.07 mm2; 95% CI, 0.89–1.25 mm2) but not in the larger lumen area group (mean of difference, −0.07 mm2; 95% CI, −0.22–0.08 mm2). In the smaller lumen group, the mean difference was lower in the Bland-Altman plot of IVUS and LATM (0.46 mm2; 95% CI, 0.27–0.65 mm2) than in that of IVUS and SATM (1.53 mm2; 95% CI, 1.27–1.79 mm2).ConclusionSATM underestimated the lumen parameters for computed lumen segmentation in CCTA, and this may be overcome by using LATM.  相似文献   
33.
Purpose: To describe how central venous access devices (CVADs) are utilized for ambulatory oncology patients and to evaluate the rate of complications. Method: Single institution retrospective study of oncology patients with CVADs who received systemic treatment at the Walker Family Cancer Centre (WFCC) between 1 January and 31 December 2018. Results: A total of 480 CVADS were placed in 305 patients, of which 408 (85%) were peripherally inserted central catheters (PICCs) and 72 (15%) were implanted vascular access devices (PORTs). The incidence of early and late complications was 9% and 24%, respectively. For the entire cohort, the rate of venous thromboembolism (VTE) was 16%, of which 9% were CVAD-related thrombosis (CRTs) and 7% were distant VTE. The CRT rates were similar for PICCs and PORTs (9% vs. 7%). A total of 6% of CVADs were complicated by infection (i.e., localized infections and bacteremia), with a total infection rate of 0.43 and 0.26 per 1000 indwelling days for PICCs and PORTs, respectively. The incidence of central line associated bloodstream infections (CLABSI) was greater for PICCs than PORTs, at a rate of 0.22 compared with 0.08 per 1000 indwelling days, respectively. The premature catheter removal rate was 26% for PICCs and 18% for PORTs. PORTs required more additional hospital visits. Conclusions: PICCs were utilized more frequently than PORTs and had a higher rate of premature removal. The rates of VTE and CRT were similar for both CVAD types. PORTs had a lower rate of infection per 1000 indwelling days. However, the management of PORT related complications required more visits to the hospital and oncology clinic.  相似文献   
34.
35.
36.
37.
Respiratory cysts are benign lesions lined by normal respiratory epithelium. There are few reported cases localized to the orbit, while those of the eyelid are exceedingly rare. Respiratory cysts usually arise either from a non‐hereditary congenital malformation, where they are distinguished as choristomatous, or from trauma. Here, we report a case of a 53‐year‐old man who presented with a large right lower eyelid cyst that was histopathologically diagnosed as a respiratory cyst.  相似文献   
38.
Rationale:Tarlov or perineurial cysts are nerve root lesions often found in the sacral region. Most perineural cysts (PCs) remain asymptomatic throughout a patient''s life. While their pathogenesis is still unclear, trauma resulting in hemorrhaging into subarachnoid space has been put forward as a possible cause of these cysts. Recently, we worked with a patient experiencing symptomatic PCs after spontaneous subarachnoid hemorrhage.Patient concerns:A 45-year-old man had a coil embolization procedure performed after being diagnosed with a subarachnoid hemorrhage from a ruptured anterior communicating artery. His symptoms were relieved after the procedure, but 7 days later he reported worsening pain in the left perineal area. The pain was intermittent at its onset and exacerbated by sitting, walking, and coughing.Diagnoses:Two weeks after the embolization procedure, a lumbar spine MRI revealed 2 PCs at the S1 and S2 level affecting the left S2 root with high signal intensity in T2 and T1 images, suggestive of bleeding within the cyst.Interventions:We operated using a posterior approach. Cyst fenestration was done after S1 laminectomy. We aspirated approximately 1 cc of old blood.Outcomes:His pain was relieved immediately after cyst removal and no neurologic deterioration occurred during the postoperative period.Lessons:Subarachnoid hemorrhage can be the source of the development of pain from asymptomatic PCs, making them symptomatic. Surgical extirpation is 1 treatment option for these symptomatic PCs.  相似文献   
39.
Introduction: Malnutrition increases the risk of cancer treatment-related complications. Nutritional intervention is beneficial for the outcomes of outpatients with cancer. This study investigated the impacts of nutrition consultation and care on energy intake and weight change in inpatients receiving cancer treatment.

Methods: We conducted a longitudinal study, enrolling 3221 inpatients with head and neck, lung, hepatobiliary, upper gastrointestinal, colorectal, breast, or gynecological cancer who received at least two nutrition consultations between April 2010 and July 2015. In every consultation, a dietitian calculated the total energy requirement and the actual energy intake was assessed using a 24-h dietary recall.

Results: Patients with head and neck cancer lost the most weight (1.16?kg/mo). For every consultation, a 0.03-kg weight gain per month was observed (P?=?0.001). The average energy consumption percentage (% estimated energy requirement) at the third consultation was 87.0%. After controlling for potential covariates, the energy consumption percentages at the third, fourth, fifth–seventh, eighth, and subsequent consultations were significantly higher than those at the first consultation (P?<?0.05).

Conclusion: For oncology inpatients, routine screening and at least three active nutrition consultations with dietitians effectively improved energy intake and preserved body weight.  相似文献   

40.
Erythema induratum of Bazin (EIB) is a form of tuberculid resulting from hypersensitivity to tuberculosis antigen. EIB occurs most commonly in middle‐aged women and is not typically seen in children. Here, we present a rare case of EIB, presenting as a chronic nodular panniculitis, in a 10‐year‐old Korean boy.  相似文献   
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