全文获取类型
收费全文 | 66402篇 |
免费 | 5945篇 |
国内免费 | 4570篇 |
专业分类
耳鼻咽喉 | 531篇 |
儿科学 | 770篇 |
妇产科学 | 488篇 |
基础医学 | 6089篇 |
口腔科学 | 1675篇 |
临床医学 | 8171篇 |
内科学 | 7948篇 |
皮肤病学 | 798篇 |
神经病学 | 2655篇 |
特种医学 | 3004篇 |
外国民族医学 | 31篇 |
外科学 | 7722篇 |
综合类 | 14343篇 |
现状与发展 | 15篇 |
一般理论 | 9篇 |
预防医学 | 5473篇 |
眼科学 | 1401篇 |
药学 | 6865篇 |
68篇 | |
中国医学 | 4411篇 |
肿瘤学 | 4450篇 |
出版年
2024年 | 250篇 |
2023年 | 910篇 |
2022年 | 2148篇 |
2021年 | 3063篇 |
2020年 | 2511篇 |
2019年 | 1838篇 |
2018年 | 1979篇 |
2017年 | 1989篇 |
2016年 | 1687篇 |
2015年 | 2898篇 |
2014年 | 3821篇 |
2013年 | 3984篇 |
2012年 | 5808篇 |
2011年 | 6278篇 |
2010年 | 4985篇 |
2009年 | 4382篇 |
2008年 | 4467篇 |
2007年 | 4214篇 |
2006年 | 4070篇 |
2005年 | 3461篇 |
2004年 | 2392篇 |
2003年 | 2001篇 |
2002年 | 1646篇 |
2001年 | 1179篇 |
2000年 | 1056篇 |
1999年 | 844篇 |
1998年 | 562篇 |
1997年 | 498篇 |
1996年 | 343篇 |
1995年 | 289篇 |
1994年 | 264篇 |
1993年 | 155篇 |
1992年 | 164篇 |
1991年 | 137篇 |
1990年 | 109篇 |
1989年 | 90篇 |
1988年 | 76篇 |
1987年 | 76篇 |
1986年 | 61篇 |
1985年 | 30篇 |
1984年 | 22篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1979年 | 9篇 |
1973年 | 7篇 |
1972年 | 9篇 |
1969年 | 9篇 |
1932年 | 10篇 |
1930年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Yang GY Mao Y Zhou LF Gong C Ge HL Betz AL 《Brain research. Molecular brain research》1999,65(2):143-150
Our previous studies have demonstrated that overexpression of recombinant human interleukin-1 receptor antagonist protein (IL-1ra) via gene transfer can reduce ischemic brain injury. However, the mechanism of action of IL-1ra in ischemia is unclear. Since interleukin-1 can up-regulate intercellular adhesion molecules in endothelium, the present study was designed to determine whether overexpression of the IL-1ra can reduce the expression of intercellular adhesion molecule-1 (ICAM-1) after ischemic injury. Normal saline or adenovirus vector (1x109 particles) encoding the human IL-1ra gene (Ad.RSVIL-1ra) or the Escherichia coli LacZ gene (Ad.RSVlacZ) was injected into the right lateral cerebral ventricle of adult CD-1 mice. After five days, permanent middle cerebral artery occlusion (MCAO) was achieved for 24 h using an intraluminal suture. Cerebral blood flow was monitored by transcranial laser Doppler flowmetry to verify the occlusion. ICAM-1 protein was quantified using Western blot analysis and localized using immunohistochemistry. After MCAO, surface blood flow in the ischemic hemisphere was decreased to 9-11% of the baseline. There were fewer ICAM-1 positive vessels in the ischemic cortex of the Ad.RSVIL-1ra transfected mice than in the Ad.RSVlacZ transfected and saline treated mice (138+/-19 vs. 249+/-25, 284+/-22, p<0.05). Western blot analysis shows that ICAM-1 protein decreased 50-60% in the Ad. RSVIL-1ra group compared to the other two groups. There were no significant differences in the numbers of positive vessels in the ischemic basal ganglia and contralateral hemisphere among the three groups. Our studies suggest that IL-1ra overexpression can down-regulate the expression of ICAM-1 in the ipsilateral cortex in ischemic mice. Interleukin-1 may play an important role in the activation of inflammatory reaction during focal cerebral ischemia by promoting leukocyte adhesion on the endothelium cells. 相似文献
102.
Tang H Zhaofan X Liu S Chen Y Ge S 《Burns : journal of the International Society for Burn Injuries》1999,25(8):7-759
The aim of the present study is to analyze the changes of cure rate and the main causes of death in the last 40 years, and to summarize our experience in the treatment of extensive full-thickness burn patients. The clinical characteristics, cure rate and main causes of death of 73 cases with total burned area more than 90% TBSA and full-thickness burn area more than 70% TBSA were analyzed retrospectively. Among them, 21 cases (28.8%) were cured and 52 cases (71.2%) died. The cure rate increased significantly in the recent years, and the main causes of death changed from shock and sepsis in the time period 1959–1978 to sepsis and MODS in the past two decades. Due to the improvement of early comprehensive management of burn shock, aggressive surgical approach to full-thickness burn wound and potent systemic supporting measures, the survival rate increased significantly. 相似文献
103.
104.
准分子激光原位角膜磨镶术后屈光回退与术中角膜床厚度的关系 总被引:6,自引:2,他引:4
目的 探讨准分子激光原位角膜磨镶术(excimer laser insitu keratomileusis LASIK) 矫治高度近视后屈光回退与术中角膜床厚度的关系。方法 对476 例938 只眼在我院接受Lasik 治疗的患者中,发生屈光回退的病例96 例,189 只眼与未发生屈光回退的病例380 例749 只眼术中角膜床厚度及术前、术后1 w k 、1 、3 、6 m o 屈光状态的资料进行对比分析。结果 有屈光回退眼组比无屈光回退眼组平均角膜床厚度小;屈光回退眼组屈光回退程度( 术后6 mo 时) 与角膜床厚度呈负相关系,上述结果经统计学检验均有显著性差异( P < 001) ;有屈光回退眼组术后早期(1 wk) 屈光状态略成过矫,但其后屈光回退程度在0 .5a 内呈加重趋势。结论 高度近视准分子激光原位角膜磨镶术中的角膜床厚度是影响术后屈光稳定性的重要因素 相似文献
105.
五种酚类抗氧化剂活性差异的理论解释 总被引:15,自引:0,他引:15
AIM: To verify the effectiveness of structure-activity relationship (SAR) and theoretical calculation methods for antioxidants. METHODS: Preliminary elucidation on the differences of activities of 5 antioxidants was performed by SAR. Then semiempirical quantum chemistry method AM1 was employed to calculate the delta HOF value, the difference between the heat of formation of antioxidant and its free radical, which was used as a theoretical parameter to elucidate the differences of activities of the antioxidants thoroughly. RESULTS: delta HOF values of antioxidants were obtained as follows: ferulic acid, 150.58 kJ.mol-1; anion of ferulic acid, 122.64 kJ.mol-1; modified ferulic acid, 137.70 kJ.mol-1; anion of modified ferulic acid, 118.99 kJ.mol-1; salvianic acid, 134.17 kJ.mol-1; rutin, 137.83 kJ.mol-1, L-EGCG, 124.39 kJ.mol-1; paeonol, 176.79 kJ.mol-1. The differences of the antioxidant activities were elucidated, and how to further enhance the antioxidant activity was investigated as well. CONCLUSION: The SAR and calculation methods are rather effective to elucidate the differences of antioxidant activities, and present some new clues for structural modification of antioxidants to increase their activities. 相似文献
106.
107.
就近年关于对视网膜与松果体在胚胎期的发生与形成、在成年时期的结构与功能等诸多方面的相似性进行了探讨,同时对两者的相互关系与相互影响进行了分析。随着对该领域不断深入的探讨,将有益于对视觉的重新认识和眼科临床的发展。 相似文献
108.
IL-2活化瘤苗对胃癌术后复发和转移的抑制作用 总被引:3,自引:0,他引:3
目的观察用细胞因子活化的特异性瘤苗辅助常规化疗,治疗外科手术后临床Ⅲ~Ⅳ期胃癌患者,抑制肿瘤术后复发、转移的临床疗效。方法于外科术后常规化疗结束后2周,用患者自体肿瘤细胞抗原致敏、IL-2活化的树突状细胞(DC)作为瘤苗给患者四肢皮下多点免疫注射1×106/(ml·次),每周1次,每疗程注射4次,0.5年后强化1次。定期胃镜、影象学和肿瘤标志物检查,随访至手术后第2年,观察生存期和生存率。结果经瘤苗治疗后,患者的免疫功能显著改善。术后24个月,瘤苗联合化疗组患者的生存率为50%,血清中CEA和CA724分别为(10±1.5)ng/ml和(5.5±1.5)U/ml,而单纯化疗组患者的生存率为10%,CEA和CA724的水平分别为(77.0±9.4)ng/ml和(55.0±7.6)U/ml;P<0.001。结论特异性瘤苗免疫治疗,能增强胃癌患者术后的特异性抗肿瘤免疫功能,提高手术后化疗疗效,抑制肿瘤复发和转移,能延长患者生存期,提高生存率。 相似文献
109.
110.
电位滴定法的计算原理及Excel软件应用 总被引:1,自引:0,他引:1
阐述了电位滴定法的计算原理以及Excel软件在电位滴定数据处理中的应用。 相似文献