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   13423篇
  免费   859篇
  国内免费   210篇
耳鼻咽喉   56篇
儿科学   110篇
妇产科学   58篇
基础医学   1412篇
口腔科学   266篇
临床医学   1143篇
内科学   2059篇
皮肤病学   248篇
神经病学   2518篇
特种医学   462篇
外国民族医学   1篇
外科学   931篇
综合类   1294篇
预防医学   1906篇
眼科学   267篇
药学   1071篇
  5篇
中国医学   459篇
肿瘤学   226篇
  2024年   17篇
  2023年   323篇
  2022年   428篇
  2021年   663篇
  2020年   624篇
  2019年   686篇
  2018年   578篇
  2017年   372篇
  2016年   383篇
  2015年   356篇
  2014年   865篇
  2013年   716篇
  2012年   696篇
  2011年   773篇
  2010年   637篇
  2009年   586篇
  2008年   580篇
  2007年   582篇
  2006年   471篇
  2005年   365篇
  2004年   325篇
  2003年   301篇
  2002年   255篇
  2001年   218篇
  2000年   189篇
  1999年   176篇
  1998年   166篇
  1997年   130篇
  1996年   126篇
  1995年   131篇
  1994年   128篇
  1993年   116篇
  1992年   109篇
  1991年   119篇
  1990年   116篇
  1989年   98篇
  1988年   98篇
  1987年   98篇
  1986年   110篇
  1985年   176篇
  1984年   129篇
  1983年   102篇
  1982年   80篇
  1981年   78篇
  1980年   56篇
  1979年   49篇
  1978年   20篇
  1977年   33篇
  1976年   21篇
  1973年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm2, p = 0.01; 3 months: 2.90 ± 1.36 mm2, p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval.  相似文献   
42.
43.
44.
目的探讨青海地区原发性与获得性耐药结核病的危险因素及临床发病风险预测模型构建。方法选取2018年7月-2019年7月青海地区132例耐药结核病患者为观察组,青海地区132例非耐药结核病患者为对照组,查阅患者的的临床资料,并自制调查问卷,以问卷调查的方式收集患者的相关信息,分析两组患者的临床指征,采用多因素Logistic回归分析完成风险模型建立,绘制ROC曲线分析风险模型的预测效能。结果单因素结果表明:青海地区原发性与获得性耐药结核病发生率与年龄、性别、与患者接触、3月底痰涂片结果无统计学意义(P>0.05);与居住地、婚姻状况、家庭收入、治疗末痰涂片结果、体重指数、抗结核药物性肝损害、结核病灶数、结核空洞、合并糖尿病及登记分类初治具有统计学意义(P<0.05);多因素logistic结果表明:青海地区原发性与获得性耐药结核病发生率与居住地、登记分类、体重指数、抗结核药物性肝损害、3月末肺结核病灶数及痰涂片结果,具有统计学意义(P<0.05);ROC曲线结果表明:构建获得性耐药结核病发病风险预测模型用于青海地区原发性与获得性耐药结核病患者中ACU值为0.847,预测敏感性为87.46%,特异性为90.29%。结论青海地区原发性与获得性耐药结核病危险因素较多,不同因素能相互作用、相互影响,构建获得性耐药结核病发病风险预测模型,能较好的预测临床发病,有助于指导临床诊疗。  相似文献   
45.
建立华细辛和北细辛HPLC特征图谱并结合聚类分析研究2种来源细辛的识别方法;应用网络药理学方法预测细辛潜在抗炎靶点并寻找潜在抗炎成分。对89批细辛药材(12批华细辛和77批北细辛)的数据进行分析确定了11个特征峰,用对照品、紫外光谱和LC-MS指认了11个特征成分。特征峰面积聚类分析显示华细辛和北细辛被分为2类,且利用特征峰面积比值可实现两者区分,当特征峰9(细辛素)/参照峰S(卡枯醇)峰面积比值大于5时为华细辛,小于2时为北细辛。对119种细辛成分进行网络药理学分析的结果表明细辛抗炎作用可能与COX-2,COX-1,iNOS,MAPK14,LAT4H,NR3C1,PPARG和TNF等8个靶点相关,其中COX-2最为关键,与5种特征成分细辛脂素、芝麻脂素、细辛素、甲基丁香酚和黄樟醚均存在相互作用。此外,细辛脂素、芝麻脂素与iNOS,MAPK14也存在相互作用关系,黄樟醚和细辛素可作用于iNOS,COX-1,LAT4H,甲基丁香酚可作用于COX-1,LAT4H。细辛脂素与芝麻脂素均可作用在COX-2,iNOS和MAPK143个靶点上,提示它们是细辛发挥抗炎作用的活性成分;COX-2分子对接结果和COX-2活性实验结果验证了细辛脂素、芝麻脂素可抑制COX-2活性,为细辛抗炎作用活性成分。基于HPLC特征图谱的华细辛和北细辛识别方法简便易行;预测到的细辛抗炎靶点和抗炎成分为完善细辛质量评价体系奠定了基础。  相似文献   
46.
目的观察活心方对结扎冠状动脉前降支所致急性心梗大鼠血流动力学及梗死面积的影响。方法采用结扎冠状动脉前降支的方法构建急性心梗模型,大鼠随机分为假手术组、模型组、贝复济组、血竭小复方组和活心方组,干预8周。检测大鼠血流动力学指标,HE染色观察心肌组织形态改变,计算梗死面积。结果模型组大鼠心肌梗死面积与左室收缩压(LVSP)及左室内压最大变化速率(+LVdp/dtmax)呈负相关(P=0.001),与左室舒张末期压(LV-EDP)呈正相关(P=0.005)。与模型组比较,活心方组、血竭小复方组大鼠LVSP均升高(P<0.05,P<0.01),LV-EDP降低(P<0.01),+LVdp/dtmax加大(P<0.01),-LVdp/dtmax加大(P<0.05,P<0.01),梗死面积缩小(P<0.01);与血竭小复方组比较,活心方组大鼠LVSP增高(P<0.05)、+LVdp/dtmax加大(P<0.05);梗死面积更小(P<0.05)。结论心肌梗死大鼠梗死面积与血流动力学指标存在相关性。活心方干预能缩小心梗大鼠的梗死面积,改善心梗后大鼠左室舒缩功能,并优于血竭小复方。  相似文献   
47.
48.
49.
《The ocular surface》2020,18(4):926-935
PurposeTo visualize and quantify vascular networks in individuals with ocular surface squamous neoplasia (OSSN) through optical coherence tomography angiography (OCTA).MethodCross-sectional study of OSSN patients. Vascular networks were measured by OCTA in the epithelium and sub-epithelial space in the tumors, adjacent tissue, and in the contralateral eye. Vessel area density (VAD, percent of blood vessels within 2.14 mm2), was calculated for each location. Total tumor density (TTD, percent of blood vessels within the entire tumor) was calculated. VAD was assessed separately for corneal and conjunctival locations and compared.ResultsFifteen patients with OSSN were included. The mean age was 61 ± 12 years and the majority were male (80%). The mean tumor area, volume, depth, and TTD were 28.0 ± 9.0 mm2 (range, 10.9–39.7), 9.1 ± 4.1 mm3 (range, 3.4–18.8), 334 ± 125 μm (range, 177–571), and 33.2% ± 11.0% (range, 18.7–58.8), respectively. The VAD was highest within the tumor (28.9% ± 8.7%) followed by the adjacent sub-epithelial tissue and the tissue underneath the conjunctival component of tumor. These densities were higher than the VAD in the tissues of the non-involved eye (all P < 0.05). The VAD within conjunctival component of tumor was significantly higher than those with corneal component (29.8% ± 9.5% vs. 21.1% ± 5.5%, p = 0.006). The VAD under conjunctival tumor was also significantly higher than under corneal component (24.1% ± 7.8% vs. 17.0% ± 6.1%, p = 0.024).ConclusionsOCTA imaging allowed for visualization and quantification of vessel structure and density within, under, and surrounding OSSN.  相似文献   
50.
When designing and interpreting results from clinical trials evaluating treatments for children on the autism spectrum, a complicating factor is that most children receive a range of concurrent treatments. Thus, it is important to better understand the types and hours of interventions that participants typically receive as part of standard of care, as well as to understand the child, family, and geographic factors that are associated with different patterns of service utilization. In this multi-site study, we interviewed 280 caregivers of 6-to-11-year-old school-aged children on the autism spectrum about the types and amounts of interventions their children received in the prior 6 weeks. Reported interventions were coded as “evidence-based practice” or “other interventions,” reflecting the level of empirical support. Results indicated that children received a variety of interventions with varying levels of empirical evidence and a wide range of hours (0–79.3 h/week). Children with higher autism symptom levels, living in particular states, and who identified as non-Hispanic received more evidence-based intervention hours. Higher parental education level related to more hours of other interventions. Children who were younger, had lower cognitive ability, and with higher autism symptom levels received a greater variety of interventions overall. Thus, based on our findings, it would seem prudent when designing clinical trials to take into consideration a variety of factors including autism symptom levels, age, cognitive ability, ethnicity, parent education and geographic location. Future research should continue to investigate the ethnic, racial, and socioeconomic influences on school-aged intervention services.  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