全文获取类型
收费全文 | 117582篇 |
免费 | 7942篇 |
国内免费 | 4282篇 |
专业分类
耳鼻咽喉 | 721篇 |
儿科学 | 2872篇 |
妇产科学 | 2003篇 |
基础医学 | 24756篇 |
口腔科学 | 1921篇 |
临床医学 | 8170篇 |
内科学 | 22342篇 |
皮肤病学 | 1962篇 |
神经病学 | 6332篇 |
特种医学 | 1821篇 |
外国民族医学 | 12篇 |
外科学 | 6861篇 |
综合类 | 14670篇 |
现状与发展 | 22篇 |
预防医学 | 12199篇 |
眼科学 | 1293篇 |
药学 | 11890篇 |
21篇 | |
中国医学 | 3251篇 |
肿瘤学 | 6687篇 |
出版年
2024年 | 160篇 |
2023年 | 1627篇 |
2022年 | 4252篇 |
2021年 | 4586篇 |
2020年 | 3698篇 |
2019年 | 3614篇 |
2018年 | 3606篇 |
2017年 | 3606篇 |
2016年 | 3675篇 |
2015年 | 4145篇 |
2014年 | 6513篇 |
2013年 | 6989篇 |
2012年 | 6183篇 |
2011年 | 7389篇 |
2010年 | 5959篇 |
2009年 | 5769篇 |
2008年 | 5817篇 |
2007年 | 5617篇 |
2006年 | 5085篇 |
2005年 | 4519篇 |
2004年 | 4081篇 |
2003年 | 3611篇 |
2002年 | 2921篇 |
2001年 | 2612篇 |
2000年 | 2335篇 |
1999年 | 2082篇 |
1998年 | 1823篇 |
1997年 | 1828篇 |
1996年 | 1642篇 |
1995年 | 1609篇 |
1994年 | 1462篇 |
1993年 | 1172篇 |
1992年 | 992篇 |
1991年 | 879篇 |
1990年 | 763篇 |
1989年 | 661篇 |
1988年 | 635篇 |
1987年 | 499篇 |
1986年 | 457篇 |
1985年 | 822篇 |
1984年 | 728篇 |
1983年 | 519篇 |
1982年 | 537篇 |
1981年 | 443篇 |
1980年 | 384篇 |
1979年 | 343篇 |
1978年 | 266篇 |
1977年 | 190篇 |
1976年 | 196篇 |
1975年 | 129篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Takao Hashimoto Osamu Sasaki Kunihiro Yoshida Yo-ichi Takei Shu-ichi Ikeda 《Movement disorders》2003,18(10):1201-1204
We report on a family with ataxia type 6 (SCA6) showing peculiar oculomotor symptoms. The proband presented with periodic alternating nystagmus (PAN), and her 2 brothers had rebound nystagmus and gaze-evoked nystagmus. They carried the identical mutation (the number of expanded CAG repeat, 24) in the CACNA1A gene. The intrafamilial variability of oculomotor symptoms may be ascribed to factors other than CAG repeat expansion size in SCA6. 相似文献
42.
目的 观察异丙酚对 1 甲基 4 苯基 1,2 ,3 ,6 四氢吡啶 (1 methyl 4 phenyl 1,2 ,3 ,6 tetrahydropyridineMPTP)损伤的小鼠纹状体多巴胺神经元的影响以及可能的作用机制。方法 给予Propofol 10 0mg/ (kg·d)后注射MPTP 2 0mg/ (kg·d) ,用药 6d。 12d后分离纹状体应用高效液相 -电化学方法检测纹状体多巴胺、二羟基苯乙酸及高香草酸的含量水平 ,应用12 5I- β-CIT放射性配基和免疫组化的方法检测多巴胺转运蛋白的活性和黑质神经元的损伤情况。结果 异丙酚可增加MPTP模型鼠多巴胺及其代谢产物的含量 ,异丙酚处理组DA ,DOPAC ,HVA的含量分别为 (8.2 417± 1.692 ) μg/ g、(1.3 81± 0 .486) μg/g和 (1.63 3 9± 0 .5 73 ) μg/ g ,与MPTP损伤组比较 ,明显增加。异丙酚亦可抑制黑质酪氨酸羟化酶 (TH)阳性神经元的减少。MPTP组注射MPTP 6d后 ,纹状体DAT为 (5 .3 13± 0 .64 2 )与正常组 (6.992± 0 .5 48) μg/ g比较显著下降 (P <0 .0 1) ,P +M组纹状体DAT为 (6.5 65± 0 .40 5 ) ,明显高于MPTP组 (P <0 .0 1) ,即减轻纹状体内多巴胺转运蛋白密度下降。结论 异丙酚对MPTP损伤的DA神经元具有一定的保护作用 ,其保护作用可能与抑制多巴胺转运蛋白活性有关 相似文献
43.
利培酮治疗与细胞色素P4502D6/C188T酶基因多态性的关联分析 总被引:2,自引:0,他引:2
目的 研究利培酮临床效应的个体差异与其代谢酶细胞色素P4 5 0 2D6 (cytochromeP4 5 02D6 ,CYP2D6 )酶基因多态性的相关性。方法 对 88例符合CCMD 3精神分裂症诊断标准的患者和 96例健康对照者作病例 -对照分析。精神分裂症患者给予利培酮治疗 8周 ,用阳性和阴性症状量表 (posi tiveandnegativesymptomscale ,PANSS)评分评价利培酮疗效。采用聚合酶链反应扩增及限制性片段长度多态性 (PCR RFLP)技术对CYP2D6exonⅠ的C188T位点突变进行检测 ,分析利培酮临床效应与其主要代谢酶CYP2D6 /C188T酶基因多态性的相关性。结果 中国上海地区人群的CYP2D6 /C188T突变率(弱代谢型 )为 36 .3% ,病例组和正常对照组间基因型频率总体分布比较无显著差异 (χ2 =1.15 ,df=2 ,P >0 .0 5 ) ,两组间的等位基因频率之间比较也无显著性差异 (χ2 =0 .78,df=1,P >0 .0 5 )。进行性别及有否家族史分组后分析 ,亦无差异存在 ,且CYP2D6 /C188T突变与利培酮临床效应之间并无相关性 (χ2 =1.12 ,df=2 ;χ2 =0 .0 3,df=1,P >0 .0 5 )。结论 未发现中国人CYP2D6 /C188T多态性与利培酮临床效应的个体差异有相关性。 相似文献
44.
Liviana Da Dalt Silvia Callegaro Silvia Carraro Barbara Andreola Massimo Corradi Eugenio Baraldi 《Pediatric allergy and immunology》2007,18(2):100-104
Respiratory syncytial virus (RSV) bronchiolitis is a very common infection in infants and, after the acute phase, a number of patients develop a reactive airway disease that lasts for years. Although the pathogenesis of the lung damage after RSV bronchiolitis is still largely unknown, previous studies suggest that leukotrienes may play an active part in it. The aim of this study was to measure leukotriene levels in the nasal lavage fluid (NLF) collected in infants during RSV bronchiolitis and 1 month later. Cysteinyl leukotrienes (Cys-LTs) and leukotriene B(4) (LTB(4)) were measured in the NLF of 22 infants with their first episode of RSV bronchiolitis and 16 healthy infants. A second NLF sample was collected to measure leukotriene levels 1 month after the acute disease. NLF Cys-LT levels were significantly higher in infants with RSV bronchiolitis than in healthy controls [950 pg/ml (285.5-2155.9) vs. 110.5 pg/ml (66.5-451.3), p = 0.01], and they remained so a month after the acute infection (p = 0.02). A subanalysis showed no difference in Cys-LTs concentrations, either between bronchiolitis infants with and without a family history of atopy, or between those with and without passive exposure to cigarette smoke. No significant difference was found between the LTB(4) levels measured in the bronchiolitis cases and the control children. Cys-LTs are significantly increased in the NLF of infants with acute RSV bronchiolitis, and remain so at 1-month follow-up, suggesting a possible role of these eicosanoids in the pathogenesis of the disease. 相似文献
45.
SHIGEKI OCHI MORIKAZU ONJI KAZUHITO SHIRAISHI KYOKO OHTU TOMOHIRO AKAO YOSHITO YANO NOBUYUKI TAKEI HIKARU MATSUI YASUYUKI OHTA MASAKICHI UMEDA 《Journal of gastroenterology and hepatology》1991,6(6):599-602
To clarify the prevalence of concurrent infection with hepatitis C virus (HCV), hepatitis B virus (HBV) and human T cell leukaemia virus (HTLV), we measured HCV antibody in the population of a district endemic for HBV and HTLV infection. Blood samples were collected in June 1990 from 579 inhabitants of four islands of Uwa Bay in the southwest of Ehime Prefecture in Japan. Anti-HCV antibody against C100-3 protein was detected using an enzyme-linked immunosorbent assay kit (Ortho Diagnostics). Thirteen of the 579 inhabitants (2.2%) were positive for anti-HCV, and this prevalence rate was not significantly different from the frequency of anti-HCV in Tokyo blood donors. A total of 11% (64 of 579) of the subjects were positive for HBsAg and 3.3% (19 of 579) were positive for anti-HTLV. These frequencies of HBsAg and anti-HTLV positivity were distinctly higher than the respective means of Japanese. All anti-HCV positive individuals were negative for HBsAg and anti-HTLV, while 54% (7 of 13) had increased alanine aminotransferase levels. These data suggest that the prevalence of HCV infection is not high even in an area endemic for HBV and HTLV infection. 相似文献
46.
Establishment and characterization of a chronic infectious mononucleosislike syndrome in common marmosets 总被引:1,自引:0,他引:1
E A Emini J Luka M E Armstrong F S Banker P J Provost G R Pearson 《Journal of medical virology》1986,18(4):369-379
Epstein-Barr virus (EBV) was inoculated into two species of marmosets. Successful infection was established in the majority of the animals of one species, Callithrix jacchus, as evidenced by the development of high, persistent levels of antibody against virus-specific capsid and early nonstructural proteins. Antibodies also were produced against the major membrane antigen and, in some animals, against EBV nuclear antigen (EBNA) 2 but not against EBNA 1. This is the antibody profile normally noted in individuals with chronic infectious mononucleosis (IM). EBV-induced lymphoproliferation was not seen, and EBV-specific proteins were not detected in the peripheral blood lymphocytes of infected animals. Hence, EBV infection in C. jacchus apparently does not generally include extensive B-cell involvement. However, the marmosets clearly are useful as a model for EBV primary infection and also possibly for chronic IM. 相似文献
47.
Human glioma cells obtained from established cell lines (Tp-276MG, Tp-301MG, Tp-378MG, Tp-483MG and U-251MG) were analyzed for the presence of ion channels with the tight-seal voltage clamp technique. The current-voltage relation revealed a marked inward rectification at hyperpolarizing voltages, due to the presence of inward rectifying K-channels in cells from all studied cell lines. These channels were conducting when the membrane potential was more negative than the K-equilibrium potential. The slope conductance for the inward K-currents (gKi) was affected both by [K+]i and [K+]0. gKi was proportional to [K+]0 raised to 0.35 or 0.50, of which the larger value was measured in the presence of low [K+]i (25mM). The rectification was not significantly different in cells perfused with Mg-free EDTA-buffered internal solution. Tl+ was 3.5 times more permaant than K+. gki was blocked by Cs+ (1 mM) in a voltage-dependent way (more effective in the hyperpolarized membrane), and by Na+ (154 mM) depending on voltage and time. From measurements of unitary current events in membrane patches (outside out or cell attached) the conductance of the single inward rectifying channel was estimated to be 27 ± 7 pS. This type of ion channel may be important for K-uptake by glial cells and hence for the K-homeostasis in the brain. 相似文献
48.
Mary Ellen Turner Kanwal Kher Tamara Rakusan Lawrence D’Angelo Sudesh Kapur Dena Selby Patricio E. Ray 《Pediatric nephrology (Berlin, Germany)》1997,11(2):161-163
We describe the clinical and pathological findings of the hemolytic uremic syndrome (HUS) in two children with human immunodeficiency
virus (HIV) infection. Both patients presented with microangiopathic hemolytic anemia, thrombocytopenia, and subsequently
developed renal failure. The diagnosis of HUS was confirmed by renal histopathology in both patients. None of these children
presented with bloody diarrhea, evidence of circulating antibody response to Escherichia coli O157 lipopolysaccharide, or other known risk factors for HUS, except for the presence of HIV infection. Each patient was
treated with intravenous plasma infusion and renal replacement therapy. Their clinical course was characterized by non-oliguria
and lack of significant hypertension throughout the acute phase of the disease. Despite these favorable clinical parameters,
both patients developed end-stage renal failure. The etiology of this atypical HUS characterized by poor renal survival remains
unknown and the role of HIV infection in its pathogenesis, although possible, is unclear.
Received March 5, 1996; received in revised form and accepted October 15, 1996 相似文献
49.
Tomoyuki TAKANO Masaki OHNO Tsunekazu YAMANO Morimi SHIMADA 《Congenital anomalies》1991,31(3):129-139
Abstract This study was undertaken to elucidate the pathogenesis of the hydrocephalus and aqueductal stenosis induced by intracerebral mumps virus inoculation in suckling hamsters.
Mild ventricular dilatation became apparent after 5 days of inoculation. Focal denuding of the ependymal layer and subsequent aqueductal stenosis were observed by 14 days after inoculation. The virus antigen was detected not only in the ependymal cells and choroid plexus, but also in some neurons in the cerebral cortex, hippocampus, midbrain and cerebellum. In the cerebral aqueduct, the orderly arrangement of the cilialy clusters was destroyed on the 5th day after inoculation. After 10 days, proliferation of GFAP positive cells was noticed around the cerebral aqueduct and subsequently caused aqueductal stenosis. In the advanced state of hydrocephalus, the cerebellum was displaced downward and showed an elongated, atrophic and sleevelike structure similar to the Arnold-Chiari malformation. It was suggested that the extensive damage of the ependymal cilia may account for early ventricular dilatation, and subsequent aqueductal stenosis with glial proliferation is the main cause of the advanced hydrocephalus. It has not yet been determined whether the mumps virus can pass through the human placenta or not. If it can, however, our results strongly suggest that mumps virus infection in the human fetus will cause congenital hydrocephalus. 相似文献
Mild ventricular dilatation became apparent after 5 days of inoculation. Focal denuding of the ependymal layer and subsequent aqueductal stenosis were observed by 14 days after inoculation. The virus antigen was detected not only in the ependymal cells and choroid plexus, but also in some neurons in the cerebral cortex, hippocampus, midbrain and cerebellum. In the cerebral aqueduct, the orderly arrangement of the cilialy clusters was destroyed on the 5th day after inoculation. After 10 days, proliferation of GFAP positive cells was noticed around the cerebral aqueduct and subsequently caused aqueductal stenosis. In the advanced state of hydrocephalus, the cerebellum was displaced downward and showed an elongated, atrophic and sleevelike structure similar to the Arnold-Chiari malformation. It was suggested that the extensive damage of the ependymal cilia may account for early ventricular dilatation, and subsequent aqueductal stenosis with glial proliferation is the main cause of the advanced hydrocephalus. It has not yet been determined whether the mumps virus can pass through the human placenta or not. If it can, however, our results strongly suggest that mumps virus infection in the human fetus will cause congenital hydrocephalus. 相似文献
50.