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   8520篇
  免费   817篇
  国内免费   286篇
耳鼻咽喉   85篇
儿科学   76篇
妇产科学   56篇
基础医学   1066篇
口腔科学   744篇
临床医学   825篇
内科学   896篇
皮肤病学   145篇
神经病学   349篇
特种医学   1073篇
外国民族医学   1篇
外科学   720篇
综合类   1189篇
预防医学   306篇
眼科学   418篇
药学   1020篇
  3篇
中国医学   284篇
肿瘤学   367篇
  2024年   25篇
  2023年   138篇
  2022年   262篇
  2021年   413篇
  2020年   331篇
  2019年   310篇
  2018年   319篇
  2017年   291篇
  2016年   276篇
  2015年   297篇
  2014年   484篇
  2013年   585篇
  2012年   387篇
  2011年   464篇
  2010年   389篇
  2009年   390篇
  2008年   377篇
  2007年   393篇
  2006年   332篇
  2005年   327篇
  2004年   293篇
  2003年   270篇
  2002年   242篇
  2001年   202篇
  2000年   179篇
  1999年   149篇
  1998年   151篇
  1997年   110篇
  1996年   93篇
  1995年   117篇
  1994年   86篇
  1993年   85篇
  1992年   89篇
  1991年   80篇
  1990年   75篇
  1989年   58篇
  1988年   57篇
  1987年   47篇
  1986年   53篇
  1985年   59篇
  1984年   56篇
  1983年   41篇
  1982年   55篇
  1981年   37篇
  1980年   35篇
  1979年   31篇
  1978年   23篇
  1977年   22篇
  1976年   14篇
  1975年   11篇
排序方式: 共有9623条查询结果,搜索用时 13 毫秒
31.
家兔血清中黄芩苷的薄层扫描法测定及药动学参数   总被引:4,自引:0,他引:4  
采用薄层扫描法测定家兔血清中的黄芩甙及在兔体内的药物动力学参数。结果显示血清药物浓度在0.5~25μg/ml范围内线性关系良好,体内药物动力学呈开放性二室模型。并通过回收率试验确定了方法的准确性。  相似文献   
32.
茎突CT薄层冠状扫描在诊断茎突过长综合征中的价值   总被引:1,自引:2,他引:1  
目的 探讨“一点一线垂直法”茎突CT薄层冠状扫描在诊断茎突过长中的价值。方法测量72例双侧茎突的长度、方位、形态、厚度、尖端与咽侧壁距离,总结茎突过长病人的临床症状与诊断。 结果 ①41例67侧长度超过3.0cm,符合茎突过长的诊断;②12例12侧茎突虽未超过3.0cm(均在2.5~2.9cm),且茎突方位角>20°、末端与咽侧壁的距离<20mm,并有临床症状的应考虑茎突过长综合征;③按茎突的形态进行分型:锥型(分直锥、弧锥),束状型,分节型,发育不良型。其中分节型与临床症状有密切关系。结论 ①茎突CT薄层冠状扫描能清晰显示茎突的长度、形态、厚度、末端与咽侧壁距离,是诊断茎突过长的一种可靠方法;②“一点一线垂直法”茎突CT薄层冠状扫描无需进行图像重建,可操作性强、简捷易行、便于推广。  相似文献   
33.
目的了解马根维显(Gd-DTPA)动态增强核磁共振(MRI)评估肾积水术后疗效的应用价值。方法单侧肾积水患者11例,年龄7~42岁,平均19.5岁,均为男性;左侧肾积水9例,右侧2例;病因经静脉尿路造影(intravenousurography,IVU)和B超确诊,10例为先天性肾盂输尿管连接部狭窄(pelvicureterjunctionobstruction,PUJO),1例为输尿管中段慢性炎症所致不完全性梗阻;10例PUJO实施狭窄部成形术,另1例施行输尿管狭窄段切除并输尿管端端吻合术。应用Gd-DTPA作为对比剂,分别在术前1个月和术后3个月实施动态增强MRI检查,选取肾实质、肾盂和集合系统的类圆形区域作为兴趣区(regionofinteresting,ROI),计算不同时间点不同兴趣区的信号强度(signalintensity,SI)和相对信号强度(relativeSI,RSI),绘制T-SI曲线,对术前术后肾脏的形态和功能状态进行评估和比较。结果积水肾脏术前肾实质与术后综合评价无显著性差异(P>0.05),肾盂和集合系统排泄对比剂明显减慢,各ROI和SI以及持续时间与术后肾脏相比均有明显的差异(P<0.05)。结论动态增强MRI作为一种简单、安全无创的技术、联合评估肾形态和功能,对于评价肾积水手术疗效具有重要的临床价值。  相似文献   
34.
OBJECTIVE: To determine the impact of a hospital-coordinated discharge care plan, involving a multidisciplinary team of primary health care providers, on hospital length of stay, quality of life, and both patient and general practitioner inclusion in, and satisfaction with, discharge procedures. DESIGN: This investigation comprised a prospective, randomized, controlled, clinical trial. SETTING: This multicentre and cross-jurisdictional study focused on areas of tertiary and primary health care as well as community allied health in Western Australia. PARTICIPANTS: Patients (n = 189) with chronic cardiorespiratory diagnoses were recruited from respiratory, cardiovascular, and general medical wards at two tertiary hospitals. INTERVENTION: Subjects were randomly assigned to one of two groups. Intervention group patients received a discharge care plan in accordance with that outlined in the Australian Enhanced Primary Care Package, completed before discharge and sent to the patient's general practitioner and other community service providers for review. Control patients were discharged under existing hospital processes. Outcome measures. Patients and general practitioners were surveyed pre-discharge and 7 days post-discharge for quality of life and opinion of discharge procedures. Hospital length of stay was also determined. RESULTS: Significant improvements in discharge planning involvement, health service access, confidence with discharge procedures, and opinion of discharge based on previous experience were seen for patients who received the discharge care plan. Further, improved perceptions of mental quality of life were observed within the first week post-discharge for intervention patients. Length of stay showed no difference between groups. Extent and speed of hospital-general practitioner communication were significantly improved via the intervention. CONCLUSIONS: Our results indicate that a multidisciplinary discharge care plan, initiated before separation, improves quality of life, involvement, and satisfaction with discharge care, and hospital-general practitioner integration. As such, it possesses benefits over current Western Australian hospital discharge procedures for the care of chronically ill populations.  相似文献   
35.
The in vitro culture,maturation and cryopr-eservation of oocytes are all the i mportant parts inthe assisted reproductive technology.Mature oo-cyte(i.e.MⅡoocytes)is arrested at the meta-phase stage of meiosisⅡ,in which chromosomesare attached to the spindle microtubles and line uponthe equatorial plateinthe normal spindles.Dis-organized structure of spindles can not onlylead tosuch morphologic changes as unwound chromo-somes but also the chromosome nondisjuction andresultant aneuploid.When t…  相似文献   
36.
目的:以不同程度地减少固定桥桥体的颊舌径,观察固定桥基牙牙周膜的受力情况,了解桥体的颊舌减径是否可以减少固定桥基牙牙周的受力.方法:采用三维激光扫描与Marc软件结合的方式,建立双端固定桥桥体颊舌径分别为正常时的100%(M1)、90%(M2)、66.7%(M3)和50%(M4)的4个三维有限元模型,施加载荷,计算并分析牙周膜支持组织中的应力分布状况.结果:垂直均布加载时基牙牙周膜的受力随着咬合面积的减小而呈规律性的下降,但在垂直集中加载和斜向加载时牙周膜受力变化不显著.结论:单纯的颊舌减径并不能有效地起到降低牙周受力的作用.  相似文献   
37.
目的:观察CT定量测定在湿热内蕴型脂肪性肝病疗效评价中的价值。方法:选取本院2013年1月—2014年12月收治的60例湿热内蕴型脂肪肝患者作为研究对象,以祛脂方为主进行中医系统治疗,所有患者均在祛脂方治疗前后行普通常规CT扫描、增强CT扫描和血清肝功能生化指标检查。对比两次检查间肝脾的普通CT扫描比值、增强CT扫描比值、血清肝功能生化指标变化。结果:祛脂方中医治疗前血清ALT、AST、ALT/AST、TC水平与祛脂方中医治疗后血清ALT、AST、ALT/AST、TC水平相比,差异不明显(t=0.21,P0.05;t=0.32,P0.05;t=0.44,P0.05;t=0.15,P0.05);祛脂方治疗前TG含量与治疗后比较,组间相比差异显著(t=4.98,P0.05)。祛脂方中医治疗前普通CT扫描比值、增强CT扫描比值、肝/脾CT值比值与祛脂方中医治疗后普通CT扫描比值、增强CT扫描比值、肝/脾CT值比值相比,差异显著(t=3.58,P0.05;t=3.21,P0.05;t=3.44,P0.05)。结论:在脂肪肝中医疗效评价中,CT是一种较为理想的评价方法。  相似文献   
38.
Purpose: The aim of our study was to investigate the biomechanical properties of the cornea in primary congenital glaucoma (PCG) and to identify the potential ocular determinants, which affect the corneal biomechanical metrics. Methods: Corneal hysteresis (CH), corneal resistance factor (CRF) and central corneal thickness (CCT) were measured in 26 patients with PCG (40 eyes) with the aid of ocular response analyser. In vivo laser‐scanning confocal microscopy was used for the estimation of stromal keratocyte density (KD) and the evaluation of corneal endothelium. Twenty normal subjects (40 eyes) served as controls. Student’s t‐test and Pearson’s correlation coefficients were used for statistical analysis. p Values <0.05 were considered statistically significant. Results: Corneal hysteresis, CRF and CCT were significantly reduced in patients with PCG (all p < 0.05). Corneal hysteresis and CRF negatively correlated with the corneal diameter in both groups (r1 = ?0.53, r2 = ?0.66, p < 0.001 for CH and r1 = ?0.61, r2 = ?0.69, p < 0.001 for CRF). Moreover, we identified a significant correlation between CH and CRF with CCT in both groups (r1 = 0.51, r2 = 0.48, p < 0.001 for CH and r1 = 0.45, r2 = 0.44, p < 0.001 for CRF). Mean KD was significantly reduced both in the anterior and posterior corneal stroma in patients with PCG (764 ± 162 and 362 ± 112 cells/mm2, respectively) compared with controls (979 ± 208 and 581 ± 131 cells/mm2, respectively) (p < 0.001). There was no significant correlation between the keratocyte density in anterior and/or posterior stroma and CH or CRF in any group (r1 = 0.29, r2 = 0.31, p < 0.06). Mean endothelial cell density was also significantly reduced in PCG group (2920 ± 443 cells/mm2) compared with control group (3421 ± 360 cells/mm2) (p < 0.001). Pleomorphism and polymegalism were significantly increased in corneal endothelium of patients with PCG. Conclusions: Our results showed a significant reduction in CH and CRF in PCG. Both CH and CRF were negatively correlated with corneal diameter. A significant correlation of CH and CRF with CCT was identified in both groups. Keratocyte density was decreased in PCG, but did not have a significant impact on CH and CRF. Mean endothelial density was also decreased in PCG. Our results suggest that reduced CCT and increased corneal diameter are major ocular determinants for the modified corneal biomechanical profile in PCG, while cellular alterations in corneal stroma and endothelium have no significant biomechanical impact.  相似文献   
39.
IL‐27 is an anti‐inflammatory cytokine that triggers enhanced antitumor immunity, particularly cytotoxic T lymphocyte responses. In the present study, we sought to develop IL‐27 into a therapeutic adjutant for adoptive T cell therapy using our well‐established models. We have found that IL‐27 directly improved the survival status and cytotoxicity of adoptive OT‐1 CD8+ T cells in vitro and in vivo. Meanwhile, IL‐27 treatment programs memory T cell differentiation in CD8+ T cells, characterized by upregulation of genes associated with T cell memory differentiation (T‐bet, Eomes, Blimp1, and Ly6C). Additionally, we engineered the adoptive OT‐1 CD8+ T cells to deliver IL‐27. In mice, the established tumors treated with OT‐1 CD8+ T‐IL‐27 were completely rejected, which demonstrated that IL‐27 delivered via tumor antigen–specific T cells enhances adoptive T cells’ cancer immunity. To our knowledge, this is the first application of CD8+ T cells as a vehicle to deliver IL‐27 to treat tumors. Thus, this study demonstrates IL‐27 is a feasible approach for enhancing CD8+ T cells’ antitumor immunity and can be used as a therapeutic adjutant for T cell adoptive transfer to treat cancer.  相似文献   
40.
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