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   548篇
  免费   9篇
  国内免费   6篇
耳鼻咽喉   2篇
儿科学   1篇
妇产科学   4篇
基础医学   66篇
口腔科学   34篇
临床医学   36篇
内科学   21篇
神经病学   64篇
特种医学   12篇
外科学   72篇
综合类   40篇
预防医学   24篇
眼科学   108篇
药学   17篇
中国医学   40篇
肿瘤学   22篇
  2023年   13篇
  2022年   12篇
  2021年   16篇
  2020年   13篇
  2019年   13篇
  2018年   15篇
  2017年   9篇
  2016年   9篇
  2015年   11篇
  2014年   35篇
  2013年   33篇
  2012年   26篇
  2011年   30篇
  2010年   23篇
  2009年   33篇
  2008年   21篇
  2007年   26篇
  2006年   44篇
  2005年   25篇
  2004年   25篇
  2003年   24篇
  2002年   12篇
  2001年   9篇
  2000年   10篇
  1999年   1篇
  1998年   6篇
  1997年   7篇
  1996年   5篇
  1995年   4篇
  1994年   6篇
  1993年   4篇
  1992年   5篇
  1991年   5篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   5篇
  1985年   5篇
  1984年   3篇
  1983年   1篇
  1981年   4篇
  1980年   2篇
  1979年   3篇
  1978年   1篇
  1976年   1篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有563条查询结果,搜索用时 15 毫秒
1.
目的探讨麻醉深度对开颅手术患者术后早期认知功能的影响。方法选择2018年6月—2019年6月在北票市中心医院接受开颅手术的患者90例,随机分为浅麻醉组和深麻醉组各45例。比较两组手术前后不同时间点平均动脉压和心率变化情况。以简易智能量表评价并比较两组手术前后不同时间点的认知功能。结果两组手术前后不同时间点平均动脉压和心率差异无统计学意义(P>0.05)。两组术后第1天和第3天简易智能量表评分差异有统计学意义(P<005),术后第7天简易智能量表评分差异无统计学意义(P>0.05)。结论对于行开颅手术的患者,在保证安全的前提下进一步增加麻醉深度,并不会影响血流动力学的稳定性,而且有利于患者术后早期认知功能的恢复。  相似文献   
2.
A high resolution depth attenuation product (Kdhires) was developed using MODIS 500 m and 250 m spectral bands. The Kdhires was compared with Wang’s operational Kd for the Chesapeake Bay. Minimal differences were observed between the two methods, with greatest deviation occurring in areas of high turbidity in the tributaries. After tuning the new Kdhires, the mean absolute error and bias between the two algorithms was 0.22 m?1 and 0.026 m?1, indicating good agreement. Higher spatial resolution provides for improved retrievals along the coast and into the narrow sections of the tributaries, coinciding with areas of concern to estuarine health and coastal management applications.  相似文献   
3.
目的分析探讨高频超声对膝关节半月板急慢性损伤的诊断价值。方法选取2017年1月至2018年2月牡丹江医学院第二附属医院收治的50例膝关节半月板急慢性损伤患者(设为研究组)及50例健康体检者(设为对照组)作为研究对象,应用高频超声检测其膝关节滑膜厚度、髌上囊积液深度及滑膜血流状况,并予以对比。结果研究组患者膝关节半月板在基线外侧较为突出且可见点状或条状强回声区,内侧副韧带变形,部分患者伴有不同程度的水肿,滑膜厚度为(6.25±2.20) mm,髌上囊积液深度为(7.35±1.45) mm,滑膜血流为0级者23例、Ⅰ级者12例、Ⅱ级者12例、Ⅲ级者3例;对照组研究对象膝关节半月板回声强度中等且均匀,边缘清晰,滑膜厚度为(1. 10±0.46) mm,髌上囊积液深度为(2. 12±0.43) mm,滑膜血流为0级者38例、Ⅰ级者12例。两组研究对象膝关节滑膜厚度、髌上囊积液深度及滑膜血流状况对比,P均0.01,差异具有统计学意义。结论高频超声对膝关节滑膜厚度、髌上囊积液及滑膜血流均较敏感,在膝关节半月板急慢性损伤的诊断中特异性较高,且操作简便,可作为膝关节半月板急慢性损伤的首选诊断方法予以推广、普及。  相似文献   
4.
Epilepsy surgery uses both depth electrodes (DEs) and subdural electrodes (SE). DEs have mainly been developed and used in Europe. As we are able to use the DEs safely due to the current advanced level of technology, use of DEs has been increasing rapidly over the last decade. Unlike placement of SEs, which simply requires craniotomy, DE placement generally requires stereotactic techniques such as frame-based stereotactic or robotic arm-based methods. However, such methods are not always available at every epilepsy center. We therefore invented guide pipes for accurate DE placement. With this guide pipe and neuronavigation-based (NB) DE placement system, we are able to place DEs accurately. However, the disadvantages of our original procedure were a relatively large skin incision and the difficulty in anchoring DEs. The purpose of this technical note is to introduce a method to perform NB DE placement with a smaller skin incision and simple anchoring procedure. As we could make the skin incision smaller and achieved easier anchoring of DEs using a titanium plate, we hope this procedure will help facilities to perform DE placement with neuronavigation systems.  相似文献   
5.
6.
目的 婴儿期先天性心脏病患儿体外循环后进行营养治疗,观察比较深度水解蛋白营养剂与传统营养液对术后并发症的影响。方法 研究2012年6月至2014年6月经体外循环行外科手术治疗的262例先天性心脏病患儿,随机分为2组,分别给予深度水解蛋白营养剂(试验组)和普通婴儿奶粉(对照组)进行喂养,对比研究两组患儿术前、术后WAZ值、血生化指标(总蛋白、白蛋白、前白蛋白)变化、术后疾病的恢复情况及并发症的发病率等。结果 试验组患儿喂养的平均热卡量较对照组明显高(65.5 kcal·kg-1·d-1比57.2 kcal·kg-1·d-1),差异有统计学意义(P<0.01);两组患儿术后WAZ有明显差异(P<0.05),试验组患儿术后营养不良发病率较对照组明显降低(42.6%比50.0%);短期营养治疗后两组患儿血清白蛋白、前白蛋白有明显差异(P<0.05);体外循环术后两组患儿相关并发症(喂养不耐受、感染、乳糜胸发病率及恢复时间、呼吸机使用时间、ICU留观时间)等经统计学分析均有明显差异(P<0.01)。结论 体外循环后的先天性心脏病患儿短期内给予深度水解蛋白营养剂,可以明显改善体外循环营养丢失,减少术后相关并发症的发生,缩短患儿术后恢复时间。  相似文献   
7.
In studies of explicit memory, researchers have reliably demonstrated that mood-congruent, depressive information is especially likely to be recalled by individuals exhibiting depressed mood. Results from studies of implicit mood-congruent memory in depressed mood, however, have been largely discrepant. The current research reviews 20 studies of implicit mood-congruent memory for emotionally valenced words in the context of dysphoria and clinical depression. Meta-analytic techniques were used to summarize this research. Results indicated that depressive groups exhibited preferential implicit recall of negative information and nondepressed groups exhibited preferential implicit recall of positive information. Also, depressive implicit mood-congruent memory for negative information was associated with recall and encoding tasks that matched with regard to the perceptual versus conceptual processes required. Furthermore, self-relevance emerged as an important moderator for implicit recall in analyses that compared clinically depressed groups to nondepressed groups. These results provide partial support both for the transfer appropriate processing framework of memory and cognitive theories of depression that emphasize self-relevant information. Finally, certain participant characteristics, particularly age and severity of depressive symptoms, emerged as important moderators of the effect of group status on depressive implicit recall biases.  相似文献   
8.
The impact of the heating rate on the Ni content at the surface of the oxide layer of biomedical NiTi is explored. Heat treatment emulating common shape-setting procedures was performed by means of conventional and inductive heating for similar annealing time and temperature, applying various heating rates from ∼0.25 K s−1 to 250 K s−1. A glow discharge optical emission spectroscopy method was established and employed to evaluate concentration profiles of Ni, Ti and O in the near-surface region at high resolution. The Ni content at the surface of the differently treated samples varies significantly, with maximum surface Ni concentrations of ∼20 at.% at the lowest and ∼1.5 at.% at the highest heating rate, i.e. the total amount of Ni contained in the surface region of the oxide layer decreases by >15 times. Consequently, the heating rate is a determinant for the biomedical characteristics of NiTi, especially since Ni available at the surface of the oxide layer may affect the hemocompatibility and be released promptly after surgical application of a respective implant. Furthermore, apparently contradictory results presented in the literature reporting surface Ni concentrations of ∼3 at.% to >20 at.% after heat treatment are consistently explained considering the ascertained effect of the heating rate.  相似文献   
9.
10.
《Diabetes & metabolism》2020,46(3):230-235
AimMortality rates are decreasing in patients with diabetes. However, as this observation also concerns patients with diabetic foot ulcer (DFU), additional data are needed. For this reason, our study evaluated the 5-year mortality rate in patients with DFU during 2009–2010 and identified risk factors associated with mortality.MethodsConsecutive patients who attended a clinic for new DFU during 2009–2010 were followed until healing and at 1 year. Data on mortality were collected at year 5. Multivariate Cox proportional-hazards model was used to identify mortality risk factors.ResultsA total of 347 patients were included: mean age was 65 ± 12 years, diabetes duration was 16 [10; 27] years; 13% were on dialysis; and 7% had an organ transplant. At 5 years, 49 patients (14%) were considered lost to follow-up. Total mortality rate at 5 years was 35%, and 16% in patients with neuropathy. On multivariate analyses, mortality was positively associated with: age [hazard ratio (HR): 1.05 (1.03–1.07), P < 0.0001]; duration of diabetes [HR: 1.02 (1.001–1.03], P = 0.03]; PEDIS perfusion grade 2 vs. 1 [HR: 2.35 (1.28–4.29), P = 0.006)]; PEDIS perfusion grade 3 vs. 1 [HR: 3.14 (1.58–6.24), P = 0.001); and ulcer duration at year 1 [HR 2.09 (1.35–3.22), P = 0.0009].ConclusionMortality rates were not as high as expected despite the large number of comorbidities, suggesting that progress has been made in the health management of these patients. In particular, patients with neuropathic foot ulcer had a survival rate of 84% at 5 years.  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