全文获取类型
收费全文 | 58573篇 |
免费 | 5422篇 |
国内免费 | 4143篇 |
专业分类
耳鼻咽喉 | 646篇 |
儿科学 | 605篇 |
妇产科学 | 564篇 |
基础医学 | 6022篇 |
口腔科学 | 875篇 |
临床医学 | 7423篇 |
内科学 | 7948篇 |
皮肤病学 | 571篇 |
神经病学 | 2778篇 |
特种医学 | 2307篇 |
外国民族医学 | 36篇 |
外科学 | 6360篇 |
综合类 | 10793篇 |
现状与发展 | 13篇 |
一般理论 | 3篇 |
预防医学 | 4154篇 |
眼科学 | 1625篇 |
药学 | 6344篇 |
53篇 | |
中国医学 | 4137篇 |
肿瘤学 | 4881篇 |
出版年
2024年 | 251篇 |
2023年 | 854篇 |
2022年 | 2309篇 |
2021年 | 2940篇 |
2020年 | 2392篇 |
2019年 | 1869篇 |
2018年 | 2009篇 |
2017年 | 1997篇 |
2016年 | 1797篇 |
2015年 | 2881篇 |
2014年 | 3612篇 |
2013年 | 3326篇 |
2012年 | 4837篇 |
2011年 | 5180篇 |
2010年 | 3592篇 |
2009年 | 2911篇 |
2008年 | 3373篇 |
2007年 | 3121篇 |
2006年 | 3045篇 |
2005年 | 2808篇 |
2004年 | 1833篇 |
2003年 | 1736篇 |
2002年 | 1439篇 |
2001年 | 1186篇 |
2000年 | 1110篇 |
1999年 | 1054篇 |
1998年 | 666篇 |
1997年 | 601篇 |
1996年 | 492篇 |
1995年 | 456篇 |
1994年 | 345篇 |
1993年 | 260篇 |
1992年 | 319篇 |
1991年 | 308篇 |
1990年 | 210篇 |
1989年 | 165篇 |
1988年 | 187篇 |
1987年 | 158篇 |
1986年 | 104篇 |
1985年 | 88篇 |
1984年 | 62篇 |
1983年 | 36篇 |
1982年 | 29篇 |
1981年 | 34篇 |
1980年 | 25篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1975年 | 12篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
目的探讨阿尔茨海默氏病(AD)和帕金森氏病(PD)对老年人认知功能及日常生活能力的影响。方法对2000~2003年就诊于我院的53例AD、68例PD和60例正常人应用简易智力量表(MMSE)和日常生活能力量表(ADL)进行分析。结果AD组与对照组相比MMSE总分及各因子分、ADL总分及各单项分均有显著性差异(P<0.01):PD组与对照组相比除MMSE的记忆力和语言因子分以及ADL第13项目(打电话)外,其余均有显著性差异(P<0.05):AD组与PD组相比除ADL第7项(穿衣)外均有显著性差异(P<0.05)。结论AD和PD对老年人的认知功能和日常生活能力均有显著的影响,两者相比,AD对老年人的影响更严重、更广泛。 相似文献
62.
Interleukin-24 and its receptors 总被引:5,自引:0,他引:5
63.
64.
Liang Shan Yasushi Nakamura Misa Nakamura Toyoharu Yokoi Kennichi Kakudo 《Pathology international》1998,48(8):569-574
Hyperparathyroidism refers to a term representing a wide spectrum of parathyroid disorders that are characterized by the increased production of parathyroid hormone. Hyperparathyroidism was once thought to be tare but is now more commonly recognized, aifecting 1 in 500 women over 40 years of age. Yet the interpretation of parathyroid pathology is still controversial and confusing. Over the past 10 years, genetic changes ( ret and menin genes) involved in the pathogenesis of MEN 2 and MEN 1 have been discovered in succession. Different mutations of the calcium-sensing receptor gene have been identified in neonatal severe hyperparathyroidism and familial hypocalciuric hypercal-cemia, respectively. The HRPT 2 gene responsible for the development of heredltaty hyperparathyroidism and jaw tumors has been localized on the 1q21–31 locus. Several genetic alterations have also been characterized in primary and secondary hyperparathyroidism. Different genetic alterations appear to involve the development of different types of hyperparathyroidism. These novel advances give us new insights into the pathogenesis of hyperparathyroidism and allow better differentiation between the different types of parathyroid disorders. 相似文献
65.
Previous results indicated that the herpes simplex virus 1 (HSV-1) U(L)31 gene is necessary and sufficient for localization of the U(L)34 protein exclusively to the nuclear membrane of infected Hep2 cells. In the current studies, a bacterial artificial chromosome containing the entire HSV-1 strain F genome was used to construct a recombinant viral genome in which a gene encoding kanamycin resistance was inserted in place of 262 codons of the 306 codon U(L)31 open reading frame. The deletion virus produced virus titers approximately 10- to 50-fold lower in rabbit skin cells, more than 2000-fold lower in Vero cells, and more than 1500-fold lower in CV1 cells, compared to a virus bearing a restored U(L)31 gene. The replication of the U(L)31 deletion virus was restored on U(L)31-complementing cell lines derived either from rabbit skin cells or CV1 cells. Confocal microscopy indicated that the majority of U(L)34 protein localized aberrantly in the cytoplasm and nucleoplasm of Vero cells and CV1 cells, whereas U(L)34 protein localized at the nuclear membrane in rabbit skin cells, and U(L)31 complementing CV1 cells infected with the U(L)31 deletion virus. We conclude that rabbit skin cells encode a function that allows proper localization of U(L)34 protein to the nuclear membrane. We speculate that this function partially complements that of U(L)31 and may explain why U(L)31 is less critical for replication in rabbit skin cells as opposed to Vero and CV1 cells. 相似文献
66.
吗氯贝胺与米帕明治疗抑郁症多中心双盲对照试验 总被引:3,自引:0,他引:3
目的 :以经典抗抑郁药物米帕明为阳性对照药采用随机双盲双模拟方法对吗氯贝胺和米帕明治疗抑郁症的疗效和安全性进行研究。方法 :共纳入病人 2 0 0例 ,分别口服吗氯贝胺 3 0 0 -60 0mg d或米帕明75 -2 5 0mg d。结果 :两组病人Hamilton抑郁量表 (HAMD)以及Hamilton焦虑量表 (HAMA)总分在治疗结束时均显著下降 (P <0 0 0 1)。两组之间疗效无显著差异 (p >0 0 5 )。治疗结束时HAMD减分率分别为吗氯贝胺组 0 74± 0 2 4,米帕明组 0 74± 0 2 4(P >0 0 5 ) ;有效率吗氯贝胺组 79 4% ,米帕明组 85 4% (P >0 0 5 )。吗氯贝胺组有 10种不良反应发生频率显著低于米帕明组 ,主要是抗胆碱能、中枢神经系统及心血管系统不良反应。吗氯贝胺的疗效指数也显著高于米帕明组。结论 :吗氯贝胺是一种安全有效的抗抑郁药物 相似文献
67.
肝毒清颗粒对大鼠实验性肝纤维化的防治作用 总被引:3,自引:0,他引:3
目的 :观察肝毒清颗粒的抗纤维化作用。方法 :将Wistar雄性大鼠随机分成 6组 ,即正常对照组、模型组、肝毒清大、中、小剂量组和乙肝宁阳性组 ,采用四氯化碳诱导肝纤维化模型。于造模第 2个月始给予治疗药物。实验持续 3月后将大鼠处死取血作肝功检查及取肝组织做病理检查。结果 :肝毒清能降低AST ,升高TP、ALB ,与模型组比较 (P <0 .0 5 ) ;减轻肝脂肪变性、减少纤维组织增生、促进肝细胞再生。结论 :肝毒清对大鼠肝纤维化有明显防治作用 相似文献
68.
Encapsidation of human immunodeficiency virus type 1 (HIV-1) RNA involves specific interactions between viral Gag proteins and viral RNA elements located at the 5' untranslated region (UTR). These RNA elements are termed packaging (psi) or encapsidation (E) signals and mainly comprise the stem-loop 1 (SL1) and SL3 RNA structures. We have previously shown that deletion of the SL1 sequences is compensated by second-site mutations within Gag. Similar studies are now extended to SL3 and the results demonstrate that deletion of this RNA structure is rescued by two point mutations, i.e., A11V in p2 and I12V in nucleocapsid (NC). These two compensatory mutations are different from those associated with the rescue of SL1 deletion, suggesting that SL1 and SL3 may bind to different residues of Gag during viral RNA packaging. Analysis of virion-derived RNA in native agarose gels shows that deletion of SL3 leads to decreases in both viral RNA packaging and dimerization. These defects are corrected by the compensatory mutations A11V and I12V. Yet, defects in viral RNA dimerization at an early stage that were caused by the SL3 deletion in the context of a viral protease-negative mutation cannot be overcome by these two suppressor mutations. Therefore, the positive effects of A11V and I12V on dimerization of the SL3-deleted RNA must have taken place at the maturation stage. 相似文献
69.
Daniel Wei Liang Wang Gabriela Moribe Ana Luiza Gajardoni De M. Arruda 《Health and human rights》2021,23(1):163
Mandatory vaccination for COVID-19 has been the object of heated debate in Brazil. This article discusses the legality and constitutionality of such a policy. First, it analyzes the laws, regulations, and Supreme Court decisions that provide for the possibility of mandatory COVID-19 vaccination. Subsequently, it analyzes the constitutionality of a mandatory vaccination policy through the proportionality method to address the conflict between, on one side, the right to individual autonomy, which includes the right to refuse a medical intervention, and, on the other, health policies that interfere with individual autonomy to protect the rights to life and health. The application of this method allows for the identification of key questions that need to be answered to determine the constitutionality of a mandatory vaccination program. These questions cannot be answered a priori and in the abstract because they depend on the concrete circumstances of the pandemic, on the characteristics of the vaccine(s) against COVID-19, and on how a mandatory vaccination policy might be designed and implemented by authorities. 相似文献
70.
Candida krusei发酵生产甘油过程中,菌体生长由玉米浆限制,菌体对玉米浆的得率为1.63g/g,培养其中玉米浆浓度相同时,增加渗透压或通过流加补料限制生长阶段的菌体生长,可使甘油生产阶段的比耗糖速率减慢,比耗糖速率保持在不很高的水平,可以因消耗的葡萄糖用于生长,维持,甘油和副产物形成所占比例的变化而提高甘油得率。 相似文献