全文获取类型
收费全文 | 15407篇 |
免费 | 1611篇 |
国内免费 | 531篇 |
专业分类
耳鼻咽喉 | 239篇 |
儿科学 | 261篇 |
妇产科学 | 155篇 |
基础医学 | 1722篇 |
口腔科学 | 322篇 |
临床医学 | 1872篇 |
内科学 | 2381篇 |
皮肤病学 | 254篇 |
神经病学 | 761篇 |
特种医学 | 684篇 |
外国民族医学 | 5篇 |
外科学 | 1651篇 |
综合类 | 2153篇 |
现状与发展 | 4篇 |
一般理论 | 4篇 |
预防医学 | 1254篇 |
眼科学 | 330篇 |
药学 | 1710篇 |
20篇 | |
中国医学 | 751篇 |
肿瘤学 | 1016篇 |
出版年
2024年 | 57篇 |
2023年 | 239篇 |
2022年 | 628篇 |
2021年 | 813篇 |
2020年 | 607篇 |
2019年 | 568篇 |
2018年 | 568篇 |
2017年 | 539篇 |
2016年 | 495篇 |
2015年 | 684篇 |
2014年 | 879篇 |
2013年 | 892篇 |
2012年 | 1241篇 |
2011年 | 1106篇 |
2010年 | 813篇 |
2009年 | 647篇 |
2008年 | 791篇 |
2007年 | 791篇 |
2006年 | 753篇 |
2005年 | 630篇 |
2004年 | 560篇 |
2003年 | 545篇 |
2002年 | 477篇 |
2001年 | 331篇 |
2000年 | 321篇 |
1999年 | 256篇 |
1998年 | 159篇 |
1997年 | 134篇 |
1996年 | 118篇 |
1995年 | 104篇 |
1994年 | 81篇 |
1993年 | 51篇 |
1992年 | 77篇 |
1991年 | 89篇 |
1990年 | 58篇 |
1989年 | 56篇 |
1988年 | 57篇 |
1987年 | 51篇 |
1986年 | 32篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1980年 | 16篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1975年 | 8篇 |
1974年 | 13篇 |
1973年 | 19篇 |
1969年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Trisomy 8/8q is a common cytogenetic event in myelocytic malignancies, ranging from myelodysplastic syndrome (MDS) to acute myelocytic leukemia (AML) to blastic transformation of chronic myelocytic leukemia. Isochromosome 8q results in the same gene dosage effect. Duplication of i(8q), resulting in pentasomy 8q, has been reported only in two cases of AML. A patient with fibrosing alveolitis on prolonged cyclophosphamide treatment developed therapy-related MDS. Karyotyping, FISH, and CGH analysis showed a duplicated i(8q) among other complex abnormalities. The clinical features of 11 cases of myelocytic leukemia with pentasomy and hexasomy 8/8q were summarized. Compared with trisomy and tetrasomy 8, significant features included reduced median survival (90 days), treatment refractoriness (even with transplantation), monocytic differentiation, trilineage dysplasia, and radiation or toxin exposure. Increasing copy numbers of chromosome 8/8q may therefore be a marker of advanced leukemic evolution, exposure to toxins, underlying myelodysplasia, and an overall poor prognosis. 相似文献
112.
It has been proposed that the structure of the exons that encode the triple helical domain of the fibrillar collagen genes arose by repeated tandem duplication of an ancestral unit exon. Because these exons encode a repeat motif [(Gly-X-Y)n], sequence homology between exons may have driven the recombinational process. We have characterized a tandem duplication mutation within a COL1A1 allele of type I collagen from an infant with the lethal form of osteogenesis imperfecta. The structure of the mutation is consistent with the occurrence of an unequal crossover within a 15 base pair region of sequence identity between exons 14 and 17 of the COL1A1 gene. The recombination produced a new 81 base pair 17/14 hybrid exon and complete duplication of exons 15 and 16. The sequence implies duplication of 60 amino acid residues within the triple helical domain with preservation of the Gly-X-Y repeat. These data suggest that a recombinational mechanism that explains the hypothetical evolutionary process is active in cells, but the lethal effect of this mutation raises questions about the role of these events in creating new structures for polymeric proteins. © 1993 Wiley-Liss, Inc. 相似文献
113.
学习优秀与学习不良大学生的学习动机、自我效能和归因的比较 总被引:29,自引:2,他引:29
目的:探讨大学生成绩不良的原因和转化途径。方法:用学习动机量表、自我效能感量表和学习归因量表对学习优秀和学习不良的大学生进行测量和对比。结果:①学习优秀的大学生比学习不良的大学生的内部动机强,但两类大学生在外部动机上无差异;②学习优秀的大学生的能力和行为的自我效能水平都比学习不良的大学生高;③在成功归因和失败归因方面,两类大学生无差异。结论:采取措施提高学习不良学生学习的内部动机和自我效能水平,是转化大学生学习不良状况的必要环节。 相似文献
114.
Adoptive transfer of dendritic cells from allergic mice induces specific immunoglobulin E antibody in naïve recipients in absence of antigen challenge without altering the T helper 1/T helper 2 balance
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dendritic cells (DCs) are important in the regulation of immune responses and it has been proposed that these cells play an important role in asthma; however, their role in food allergy is still largely unknown. Our aim was to study specific immunoglobulin E (IgE) and immunoglobulin G (IgG) responses in naïve recipients following adoptive transfer of myeloid DCs from allergic and control mice. The phenotypic features and lymphokine production of DCs were also investigated. CD11c + /hi B220? DCs isolated from spleen and Peyer's patches (PP) of cow's milk (CM) allergic and control mice were transferred intravenously (i.v.) into naïve syngeneic recipients, and IgE‐ and IgG‐specific responses were evaluated. Experiments were also carried out to determine the levels of interferon‐γ (IFN‐γ) and interleukin (IL)‐4 produced by splenocytes from naïve recipients following the adoptive transfer, and CD40 ligand (CD40L)‐mediated IL‐10 production by DCs from allergic and control mice. DCs isolated from spleen and PP of allergic mice, but not control groups, induced CM‐specific IgG and IgE antibody production in naïve recipients in the absence of previous immunization, but did not modify the T helper 1 (Th1) and T helper 2 (Th2) balance. Furthermore, although no difference was observed in the expression of canonical DC surface markers, PP DCs from allergic mice produced less IL‐10 than DCs from controls. We interpret these data as showing that DCs play a pivotal role in allergen‐specific IgE responses and that a Th2‐skewed response may not be involved in the early phase of allergic responses. The identification of the mechanisms underlying these events may help to design novel strategies of therapeutic intervention in food allergy. 相似文献
115.
116.
目的:探讨公立医院医疗新技术临床应用管理体系及实践效果。方法:以某公立医疗机构为研究对象,通过文献理论研究和实践验证法探索建立新技术临床应用管理体系,并分析其在实践过程中的效果。结果:提高了医务人员申报新技术的积极性,医院专科综合实力得到显著增强,患者满意度大大提高。结论:公立医院医疗新技术临床应用管理体系有助于规范临床新技术应用的全过程管理,可促进新技术的良性发展,提高医疗服务水平。 相似文献
117.
目的:探析甘肃省某大型公立医院医疗纠纷发生的原因,并识别表面原因、过度原因及根本原因,针对性提出综合防治建议,以促进医院全面和谐发展。方法:对2015-2019年该院440例医疗纠纷案例进行历史追踪,结合访谈法深入分析其发生原因,并运用冰山分析法进行分类。结果:该院医疗纠纷发生的表面原因有3项:医疗费用过高、发生并发症、过度检查和治疗;过渡原因有9项:医患沟通不到位,不充分、就诊流程不合理、患者隐私保护不到位、诊疗行为不规范和违反常规操作、手术不当、患者期望值过高难以满足、存在心理疾病、用药不当和用药不规范、有创治疗未履行知情同意义务;根本原因有4项:诊疗能力不足及技术水平不高、服务态度差、责任意识差、管理制度落实不到位。结论:医疗机构在制定医疗纠纷的防范措施时,要从根本原因入手,从根本上解决问题。因此,在日常诊疗工作中要持续强化临床技能操作,加强医德医风建设,强化医务人员责任意识和专业服务意识,落实医疗管理制度,以最大限度地降低医疗纠纷发生率。 相似文献
118.
目的 观察桑叶黄酮降糖、改善胰岛素抵抗、抗炎作用并探讨其作用机制。方法 6~7周龄雄性db/db小鼠随机分为模型组、桑叶黄酮高、低剂量组(1.00、0.50 g·kg-1·d-1),另设同周龄C57BL小鼠为正常组。干预6周后,检测小鼠空腹血糖(FBG)、血清胰岛素水平(Fins)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、游离脂肪酸(FFA)、血肌酐(SCr)、血尿素氮(BUN)、天门冬氨酸氨基转移酶(AST)、计算胰岛素抵抗指数(HOMA-IR);检测肝脏超氧化物歧化酶(SOD)、谷胱甘肽过氧物酶(GSH-Px)、过氧化氢酶(Catalase);苏木素-伊红(HE)染色检测小鼠肝脏形态结构变化;蛋白免疫印迹法(Western blot)检测肝脏环氧合酶-2(COX-2)、一氧化氮合酶(iNOS)、核转录因子-κB(NF-κB)蛋白表达。结果 与模型组比较,桑叶黄酮高、低剂量组FBG、Fins、HOMA-IR、IL-6、TNF-α、FFA水平明显降低(P<0.05,P<0.01);肝脏SOD、GSH-Px、Catalase水平明显升高(P<0.05,P<0.01);与模型组比较,桑叶黄酮高、低剂量组HE染色显示肝细胞排列整齐,炎细胞浸润及细胞脂肪样变明显改善;与模型组比较,桑叶黄酮高、低剂量组肝脏COX-2、iNOS、NF-κB蛋白表达明显降低(P<0.05,P<0.01)。结论 桑叶黄酮具有降糖、改善胰岛素抵抗作用,其作用可能是通过调控糖尿病小鼠肝脏NF-κB分子影响COX-2、iNOS及炎症因子释放,改善炎症状态实现的。 相似文献
119.
目的探讨急性ST段抬高型心肌梗死(STEMI)患者提前肝素化的疗效及风险。方法选取2019年5月至2020年5月我院收治的160例STEMI患者作为研究对象,随机分为两组各80例。治疗组给予提前肝素化PCI术治疗,对照组给予常规肝素化PCI术治疗。比较两组的TIMI血流分级、不良事件发生率以及治疗前后的症状评分、 LVEF。结果术后,治疗组的TIMI血流0~1级率低于对照组,3级率高于对照组(P <0.05)。治疗后,两组的症状评分均低于治疗前,LVEF水平均高于治疗前(P<0.05);治疗组的症状评分低于对照组,LVEF水平高于对照组(P <0.05)。治疗组的不良事件发生率低于对照组(P <0.05)。结论 PCI术提前肝素化可以提高灌注效果,有效缓解STEMI患者的病情,改善患者心功能,改善预后,且具有较高的安全性。 相似文献
120.
Ae Kyung Park Il-Hwan Kim Junyoung Kim Jeong-Min Kim Heui Man Kim Chae young Lee Myung-Guk Han Gi-Eun Rhie Donghyok Kwon Jeong-Gu Nam Young-Joon Park Jin Gwack Nam-Joo Lee SangHee Woo Jin Sun No Jaehee Lee Jeemin Ha JeeEun Rhee Cheon-Kwon Yoo Eun-Jin Kim 《Osong Public Health and Research Perspectives》2021,12(1):37
Since a novel beta-coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in December 2019, there has been a rapid global spread of the virus. Genomic surveillance was conducted on samples isolated from infected individuals to monitor the spread of genetic variants of SARS-CoV-2 in Korea. The Korea Disease Control and Prevention Agency performed whole genome sequencing of SARS-CoV-2 in Korea for 1 year (January 2020 to January 2021). A total of 2,488 SARS-CoV-2 cases were sequenced (including 648 cases from abroad). Initially, the prevalent clades of SARS-CoV-2 were the S and V clades, however, by March 2020, GH clade was the most dominant. Only international travelers were identified as having G or GR clades, and since the first variant 501Y.V1 was identified (from a traveler from the United Kingdom on December 22nd, 2020), a total of 27 variants of 501Y.V1, 501Y.V2, and 484K.V2 have been classified (as of January 25th, 2021). The results in this study indicated that quarantining of travelers entering Korea successfully prevented dissemination of the SARS-CoV-2 variants in Korea. 相似文献