全文获取类型
收费全文 | 3929篇 |
免费 | 291篇 |
国内免费 | 281篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 27篇 |
妇产科学 | 59篇 |
基础医学 | 526篇 |
口腔科学 | 75篇 |
临床医学 | 500篇 |
内科学 | 714篇 |
皮肤病学 | 17篇 |
神经病学 | 236篇 |
特种医学 | 129篇 |
外国民族医学 | 7篇 |
外科学 | 328篇 |
综合类 | 597篇 |
现状与发展 | 1篇 |
预防医学 | 205篇 |
眼科学 | 100篇 |
药学 | 404篇 |
1篇 | |
中国医学 | 161篇 |
肿瘤学 | 395篇 |
出版年
2024年 | 13篇 |
2023年 | 74篇 |
2022年 | 181篇 |
2021年 | 225篇 |
2020年 | 153篇 |
2019年 | 129篇 |
2018年 | 118篇 |
2017年 | 121篇 |
2016年 | 103篇 |
2015年 | 175篇 |
2014年 | 209篇 |
2013年 | 194篇 |
2012年 | 302篇 |
2011年 | 305篇 |
2010年 | 165篇 |
2009年 | 136篇 |
2008年 | 195篇 |
2007年 | 184篇 |
2006年 | 182篇 |
2005年 | 216篇 |
2004年 | 130篇 |
2003年 | 152篇 |
2002年 | 104篇 |
2001年 | 75篇 |
2000年 | 91篇 |
1999年 | 91篇 |
1998年 | 69篇 |
1997年 | 71篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 34篇 |
1993年 | 28篇 |
1992年 | 21篇 |
1991年 | 32篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1971年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有4501条查询结果,搜索用时 0 毫秒
31.
Yu-Li Liu Cathy Shen-Jang Fann Chih-Min Liu Jer-Yuarn Wu Shuen-Iu Hung Hung-Yu Chan Jiahn-Jyh Chen Chin-Yu Lin Shih-Kai Liu Ming H Hsieh Tzung-Jeng Hwang Wen-Chen Ouyang Chun-Ying Chen Jin-Jia Lin Frank Huang-Chih Chou Ching-Mo Chueh Wei-Ming Liu Ming-Min Tsuang Stephen V Faraone Ming T Tsuang Wei J Chen Hai-Gwo Hwu 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(4):418-420
Several studies have suggested that the regulator of G-protein signaling 4 (RGS4) may be a positional and functional candidate gene for schizophrenia. Three single nucleotide polymorphisms (SNP) located at the promoter region (SNP4 and SNP7) and the intron 1 (SNP18) of RGS4 have been verified in different ethnic groups. Positive results have been reported in these SNPs with different numbers of SNP combinatory haplotypes. In this study, these three SNP markers were genotyped in 218 schizophrenia pedigrees of Taiwan (864 individuals) for association analysis. Among these three SNPs, neither SNP4, SNP7, SNP18 has shown significant association with schizophrenia in single locus association analysis, nor any compositions of the three SNP haplotypes has shown significantly associations with the DSM-IV diagnosed schizophrenia. Our results fail to support the RGS4 as a candidate gene for schizophrenia when evaluated from these three SNP markers. 相似文献
32.
在休克过程中,体内活性氧代谢与细胞内钙超负荷存在着相互影响。为了研究林克和复苏过程中钙拮抗剂对脂质过氧化的影响,用17只杂种犬快速放血使平均动脉压为5.32kpd,并维持90min。然后回输全部失血。在休克30min时,各组别静脉注射(15min内)硫氮酮(40g/kg·min ̄(-1)),异搏定(10μg/kg·min ̄(-1)),或等量生理盐水。复苏后150min处死动物,取心、肝、肺、肾、胰和小肠组织备检。结果显示,用硫氮酮和异搏定治疗组,各主要脏器组织中黄嘌呤氧化酶活性和丙二醛含量均显著低于休克对照组。而各检测组织中超氧化物歧化酶活性变化不一。这些资料显示钙拮抗剂抗休克的机制与其阻滞Ca2+内流,降低组织中黄嘌呤氧化酶活性,抑制脂质过氧化有密切关系。 相似文献
33.
新疆南疆地区嗜人T淋巴细胞病毒I型血清流行病学调查 总被引:8,自引:1,他引:8
通过血清流行病学调查,了解人嗜T淋巴细胞病毒I型(HTLV-1)在新疆南部(南疆)少数民族地区的流行情况,自南疆喀什,和田,阿图什地区采集正常人群中不同年龄组,不同民族的血清标本2642份,其中维吾尔族(维族)1082份,汉族1089份,柯尔克孜族(柯族)471份。用免疫荧光法(IFA)检测上述血清中HTLV-1IgG抗体,结果维族抗体阳性者为0.74%(8/1082)汉族为0(0/1089)柯族 相似文献
34.
35.
Androgens have potent effects on the maturation and maintenance of a number of neural pathways involved in reproductive behaviors in males. Most studies in this area have focused on central pathways, but androgen receptors are expressed by many peripheral neurons innervating reproductive organs, and previous studies have demonstrated structural and chemical changes in these neurons at puberty and after castration. We have performed the first electrophysiological comparison of pelvic autonomic ganglion neurons in male rats before and after puberty and following pre- or postpubertal castration. Studies were performed in vitro on intact ganglia with hypogastric and pelvic nerves attached to allow synaptic activation of sympathetic or parasympathetic neurons, respectively. Pelvic ganglion neurons underwent many changes in their passive and active membrane properties over the pubertal period, and some of these changes were dependent on exposure to circulating androgens. The most pronounced steroid-dependent effects were on membrane capacitance (soma size) in sympathetic neurons and duration of the action potential afterhyperpolarization in tonic neurons. Our study also showed that rat pelvic ganglion cells and their synaptic inputs were more diverse than previously reported. In conclusion, this study demonstrated that rat pelvic ganglion neurons undergo considerable postnatal changes in their electrophysiological properties. The steroid dependence of some of these changes indicates that circulating androgens may influence reproductive behaviors at many locations within the nervous system not just in the brain and spinal cord. 相似文献
36.
目的:探讨血清、尿液β2-微球蛋白(β2-mieroglobulin,β2-m)对毒性弥漫性甲状腺肿(graves diseases,Graves)患者β2-m含量与甲状腺激素的关系,了解其变化情况及临床意义。方法:采用放射免疫分析和化学发光免疫分析测定了82例Graves病初发未治疗组与同一组经治疗的69例缓解组及13例未缓解组。并和40例健康对照组进行血清、尿液β2-m含量与FT3、FL4、TGA、TMA血清检测。结果:初发组与未缓解组β2-m含量与FT3、FT4含量显著高于健康对照组(P〈0.01)。经治疗组β2-m含量与FT3、FT4含量同步缓解而下降至正常,与未治疗组对比(P〈0.01)。对比健康正常组差异无显著性(P〉0.05)。82例Graves病初发组TGA阳性率为48.7%(40/82),TMA阳性率为53.66%(44/82)。未缓解组TGA阳性率为15.38%(2/13),TMA阳性率为23.07%(3/13)。缓解组TGA、TMA仍有13.04%、15.94%阳性。结论:甲状腺疾病患者β2-m含量与甲状腺激素有密切关系,提示β2-m可作为Graves病疗效观察、病情变化及预后判断的一项辅助诊断指标。 相似文献
37.
杂种犬11只,由股动脉放血使平均动脉压(MAP)维持在6.0kPa90min后回输全部血液,继续观察150min。在休克30min后,对照组和维拉帕米处理组(Ver组)分别静脉滴注生理盐水和Ver溶液[(10μg/kg·min)15min],液体总量为3ml/kg。对照组犬在失血后心率(HR)加快,左室dp/dtmax显著降低,回输血液后MAP虽有回升,但仍低于基础值,左室dp/dtmax无明显改善;Ver使休克犬HR减慢,血液回输后MAP缓慢恢复至基础值,左室dp/dtmax显著高于对照组;电镜观察可见对照组心肌肌原纤维和线粒体等有明显的损伤,而Ver组心肌超微结构基本正常。结果还显示:Ver组犬心肌中丙二醛含量、黄嘌呤氧化酶活性低于对照组,而超氧化物歧化酶活性高于对照组。结果表明:Ver对失血性休克犬的心脏具有保护作用,其机制可能与其阻滞膜Ca2+内流、抑制脂质过氧化有关。 相似文献
38.
Qiping Yang Yue Xi Hanmei Liu Jing Luo Yufeng Ouyang Minghui Sun Cuiting Yong Caihong Xiang Qian Lin 《Nutrients》2021,13(3)
This study aims to estimate the free sugars intake, identify the primary food sources of free sugars, and explore the relationship between free sugars intake and dental caries among Chinese adolescents. This cross-sectional study included 1517 middle-school students aged 12–14 years in Changsha city, China. Adolescents completed a 12-item Food Frequency Questionnaire (FFQ) and oral health assessment. The students’ dental caries experience was available as DMFT score (number of decayed, missing, and filled permanent teeth). Statistical analyses included the Mann–Whitney test, Kruskal–Wallis test, Chi-square test, and binary logistic regression model. The average intake of free sugars was 53.1 g/d in adolescents, and 43.2% of the students consumed more than 50 g of free sugars daily. The primary contributor to free sugars was sugar-sweetened beverages (SSBs). Age, boarders, and high family income were risk factors for excessive free sugars intake (p < 0.05), and increased free sugars intake was a risk factor for dental caries (odds ratio, OR = 1.446, 95% confidence interval: 1.138–1.839). Both the free sugars intake and dental caries prevalence in Chinese adolescents were high. Targeted interventions are urgently needed to address the excessive consumption of free sugars and improve Chinese adolescents’ oral health. 相似文献
39.
异丙酚对人脐静脉内皮细胞凋亡相关基因Bcl-2及Bax表达的影响 总被引:4,自引:1,他引:3
目的 :观察异丙酚 (Propofol)及肿瘤坏死因子 α(TNF α)对培养的人脐静脉内皮细胞 (HUVECs)凋亡相关基因Bcl 2及Bax表达的影响 ,探讨异丙酚抑制凋亡的机理。方法 :将培养的人脐静脉内皮细胞 3~ 4代于融合状态 ,随机分为 7组 :对照组 (P0 ) ,2 5 μmol/L异丙酚组 (P2 5) ,TNF α组 (P0 +TNF α) ,12 .5 μmol/L异丙酚和TNF α组 (P12 .5+TNF α) ,2 5 μmol/L异丙酚和TNF α组 (P2 5+TNF α) ,5 0 μmol/L异丙酚和TNF α组 (P50 +TNF α) ,10 0 μmol/L异丙酚和TNF α组 (P10 0 +TNF α)。各组加入相应药物培养 2 4h后收获细胞 ,采用免疫细胞化学染色方法测定Bcl 2及Bax蛋白表达。结果 :与对照组 (P0 )相比 ,异丙酚 2 5 μmol/L组 (P2 5)Bcl 2及Bax蛋白表达无明显变化 (P >0 .0 5 ) ;TNF α(P0 +TNF α)组Bcl 2蛋白表达降低 ,Bax蛋白表达升高 (P <0 .0 0 1) ;而不同浓度的异丙酚预处理后再加入肿瘤坏死因子的各组 (P12 .5+TNF α、P2 5+TNF α、P50 +TNF α、P10 0 +TNF α)Bcl 2蛋白表达增加 ,Bax蛋白表达降低 (P <0 .0 5或P <0 .0 1)。结论 :临床相关浓度的异丙酚可通过调节Bcl 2及Bax蛋白表达抑制TNF α诱导的内皮细胞凋亡 相似文献
40.
Long Gongwei Zhang Yucong Sun Guoliang Ouyang Wei Liu Zheng Li Heng 《Lasers in medical science》2021,36(9):1807-1816
Lasers in Medical Science - The thulium laser resection of bladder tumor (TmLRBT) is widely used in the treatment of non-muscle-invasive bladder cancer (NMIBC), and we conduct this study to compare... 相似文献