全文获取类型
收费全文 | 88508篇 |
免费 | 8033篇 |
国内免费 | 6530篇 |
专业分类
耳鼻咽喉 | 717篇 |
儿科学 | 923篇 |
妇产科学 | 1073篇 |
基础医学 | 10864篇 |
口腔科学 | 1653篇 |
临床医学 | 12116篇 |
内科学 | 13345篇 |
皮肤病学 | 840篇 |
神经病学 | 4850篇 |
特种医学 | 3222篇 |
外国民族医学 | 62篇 |
外科学 | 8594篇 |
综合类 | 14999篇 |
现状与发展 | 30篇 |
一般理论 | 3篇 |
预防医学 | 5277篇 |
眼科学 | 2556篇 |
药学 | 9134篇 |
71篇 | |
中国医学 | 4808篇 |
肿瘤学 | 7934篇 |
出版年
2024年 | 316篇 |
2023年 | 1654篇 |
2022年 | 3874篇 |
2021年 | 4701篇 |
2020年 | 3517篇 |
2019年 | 3087篇 |
2018年 | 3152篇 |
2017年 | 2888篇 |
2016年 | 2629篇 |
2015年 | 4158篇 |
2014年 | 4942篇 |
2013年 | 4216篇 |
2012年 | 6348篇 |
2011年 | 7175篇 |
2010年 | 4307篇 |
2009年 | 3287篇 |
2008年 | 4232篇 |
2007年 | 4518篇 |
2006年 | 4447篇 |
2005年 | 4564篇 |
2004年 | 2806篇 |
2003年 | 2578篇 |
2002年 | 2231篇 |
2001年 | 1910篇 |
2000年 | 2145篇 |
1999年 | 2503篇 |
1998年 | 1667篇 |
1997年 | 1586篇 |
1996年 | 1217篇 |
1995年 | 1063篇 |
1994年 | 886篇 |
1993年 | 604篇 |
1992年 | 719篇 |
1991年 | 609篇 |
1990年 | 554篇 |
1989年 | 478篇 |
1988年 | 396篇 |
1987年 | 351篇 |
1986年 | 247篇 |
1985年 | 191篇 |
1984年 | 92篇 |
1983年 | 76篇 |
1982年 | 41篇 |
1981年 | 45篇 |
1980年 | 29篇 |
1979年 | 31篇 |
1978年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Yana Suchy David S Kosson 《Journal of the International Neuropsychological Society》2006,12(4):538-548
Three hypotheses for cognitive deficits among psychopaths were tested: executive dysfunction, left hemisphere activation, and an interaction between the two. Twenty-one psychopathic and 23 nonpsychopathic criminal offenders identified with the Hare Psychopathy Checklist-Revised participated in verbal and visual-spatial tasks during which the level of executive processing demands was manipulated. Consistent with prior research, psychopathic offenders made more errors than controls, but only during the verbal task and only on trials with high executive demand. Within those trials, most errors occurred when set-maintenance demands were the highest. No response latency differences between groups were found. 相似文献
62.
63.
J. F. Wang M. Wang J. L. Ma L. G. Jiao X. Y. Zhou J. E. Lindberg 《Transboundary and Emerging Diseases》2006,53(3):113-118
Ten multiparous lactating sows were used to investigate whether intramammary infusion of lipopolysaccharides (LPS; Escherichia coli 0111:B4; 2.0 μg/kg of body weight) would affect the circulating concentrations of Ca, P, 25‐hydroxyvitamin D (25‐OHD), tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6) and cortisol. The sows were randomly allotted to either control group (control) or LPS‐treated group with five individuals per group and were infused with either physiological saline solution or LPS solution. The rectal temperature and udder quarter appearance were recorded at 0 (just before infusion), 1, 3, 7, 12 or 24 h after infusion. Blood samples were taken at 0, 1, 3, 7, 12 or 24 h after infusion. Before infusion, the rectal temperatures of all sows were below 39.2°C. At 3 and 7 h after infusion, the sows in the LPS group had a rectal temperature over 39.4°C. At 24 h after infusion, the rectal temperatures returned to pre‐infusion levels. Serum Ca and P concentrations in the LPS group decreased (P < 0.05) after LPS infusion compared with the control group at 1 h after infusion. No significant differences (P > 0.05) in the concentrations of 25‐OHD were observed between groups control and LPS at any sampling time. Increased (P < 0.01) concentrations of serum TNF‐α, IL‐6 and cortisol were observed in the LPS group compared with the control group at 3 and 7 h after infusion respectively. In conclusion, the elevation of serum concentrations of TNF‐α, IL‐6 and cortisol and the alterations of circulating concentrations of Ca and P following LPS infusion indicate that the immune system has been activated and immune activation may affect macromineral homeostatic regulation, which might have important implications for metabolic health of lactating sows. Lowered serum Ca and P following immune activation also shows a causative mechanism whereby immune activation increases the risk of secondary disorders such as mastitis‐metritis‐agalactia syndrome. However, immune activation did not affect circulating concentrations of vitamin D metabolites. 相似文献
64.
帕金森病立体定向手术并发脑内出血的原因分析 总被引:2,自引:0,他引:2
目的:探讨帕金森病立体定向手术颅内出血并发症原因及对策。方法:自1999年4月至2003年3月我们对药物治疗效果不理想的510例帕金森病病人行立体定向毁损手术,术后出现颅内出血9例,其中毁损灶出血3例,穿刺道出血6例。结果:手术治疗4例.保守治疗5例。术后意识恢复但遗留偏瘫4例,经非手术治疗5例.恢复良好,未遗留明显功能障碍。全组无死亡病例。结论:采用磁共振结合微电极导向提高靶点定位精确度,减少微电极记录针道数,降低毁损温度,重视围手术期处理等措施,有助于降低颅内出血并发症的危险。 相似文献
65.
Rongnong Zhou Ligong Tang Kurt E. Geckeler Wolfgang Gpel 《Macromolecular chemistry and physics.》1994,195(7):2409-2421
Polystyrene-bound metal [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]phthalocyaninates were synthesized by Friedel-Crafts reaction of polystyrene with the corresponding metal phthalocyaninates. Co(II) and Cu(II) [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]-phthalocyaninate (PS-CodaPc and PS-CudaPc) contained 0,13 mmol · g?1 (12,4 wt.-%) and 0,13 mmol · g?1 (12,8 wt.-%) of CodaPc and CudaPc, respectively. They were soluble in N,N'-dimethylformamide, but only partially soluble in chloroform, tetrahydrofuran (THF), dimethyl sulfoxide, N-methyl-2-pyrrolidone, and pyridine. The THF extracts contained 0,12 mmol · g?1 (11,4 wt.-%) and 0,18 mmol ? g?1 (17,2 wt.-%) of PS-CodaPc and PS-CudaPc, respectively. The thermal stability of the polymers was studied using thermogravimetric and differential thermal analysis in nitrogen and synthetic air atmosphere. The contents of MdaPc(M: metal) in THF-extracted polymers calculated from the data of residue in thermogravimetric analysis are 0,12 mmol · g?1 for PS-CodaPc and 0,19 mmol · g?1 for PS-CudaPc. In addition, the sensitive properties of the polymers towards toxic gases were also investigated by quartz microbalance transducers. The results show that the quartz microbalance sensors coated with both polymers were sensitive to NO2 and chlorinated hydrocarbons, i.e. chloroform and perchloroethylene. The sensitivity to NO2 was 6,53 · 10?7 m3 · mL?1 · s?1 for PS-CodaPc and 1,90 · 10?6 m3 · mL?1 · s?1 for PS-CudaPc, and that to chloroform and perchloroethylene was 2,33 · 10?8 and 4,60 · 10?8 m3 · mL?1 · s?1, respectively, for PS-CodaPc and 4,79 · 10?8 and 9,51 · 10?7 m3 · mL?1 · s?1 for PS-CudaPc. 相似文献
66.
本文采用1:3病例对照研究方法,对甾体避孕药的使用与血栓栓塞性疾病(急性心肌梗塞、脑栓塞、脑血栓形成和深静脉血栓形成)间的关联进行多因素分析。结果提示在我国广泛应用的甾体避孕药(主要为国产Ⅰ号避孕药)并不增加血栓栓塞性疾病的危险性。用药和停药时间的长短与血栓栓塞性疾病的发生无关,并与高血压病之间亦不存在协同作用。 相似文献
67.
Jessica Lasky-Su Tobias Banaschewski Jan Buitelaar Barbara Franke Keeley Brookes Edmund Sonuga-Barke Richard Ebstein Jacques Eisenberg Michael Gill Iris Manor Ana Miranda Fernando Mulas Robert D Oades Herbert Roeyers Aribert Rothenberger Joseph Sergeant Hans-Christoph Steinhausen Eric Taylor Kaixin Zhou Margaret Thompson Philip Asherson Stephen V Faraone 《Neuropsychopharmacology》2007,62(9):985-990
BACKGROUND: Previous research found an association between single nucleotide polymorphisms (SNPs) in the promoter region of DRD4 and statistically derived phenotypes generated from attention-deficit/hyperactivity disorder (ADHD) symptoms. We sought to replicate this finding by using the same methodology in an independent sample of ADHD individuals. METHODS: Four SNPs were genotyped in and around DRD4 in 2631 individuals in 642 families. We developed a quantitative phenotype at each SNP by weighting nine inattentive and nine hyperactive-impulsive symptoms. The weights were selected to maximize the heritability at each SNP. Once a quantitative phenotype was generated at each SNP, the screening procedure implemented in PBAT was used to select and test the five SNPs/genetic model combinations with the greatest power to detect an association for DRD4. RESULTS: One of the four SNPs was associated with the quantitative phenotypes generated from the ADHD symptoms (corrected p-values = .02). A rank ordering of the correlation between each of the ADHD symptoms and the quantitative phenotype suggested that hyperactive-impulsive symptoms were more strongly correlated with the phenotype; however, including inattentive symptoms was necessary to achieve a significant result. CONCLUSIONS: This study partially replicated a previous finding by identifying an association between rs7124601 and a quantitative trait generated from ADHD symptoms. The rs7124601 is in linkage disequilibrium (LD) with the SNPs identified previously. In contrast to the previous study, this finding suggests that both hyperactive-impulsive and inattentive symptoms are important in the association. 相似文献
68.
69.
白藜芦醇抑制胶质瘤细胞生长与诱导细胞凋亡实验研究 总被引:6,自引:3,他引:3
目的探讨白藜芦醇(Res)对脑胶质瘤细胞(C6细胞株)和正常成纤维细胞(3T3细胞株)体外增殖的影响,进而观察Res诱导C6和3T3细胞系的凋亡作用.方法用不同浓度的Res处理C6和3T3细胞,以四甲基偶氮唑蓝(MTT)比色法检测Res对C6和3T3细胞的增殖作用,通过HE染色、扫描电子显微镜(SEM)、原位末端标记法(TUNEL)和流式细胞仪Annexin Ⅴ荧光染色,观察细胞的形态学结构改变,并定量检测细胞凋亡.结果 Res抑制了C6细胞的生长与增殖( P < 0.01 ),呈浓度依赖性反应;Res能明显诱导C6细胞凋亡,经210 μmol/L、120 μmol/L Res处理24 h后及对照组的C6细胞,其凋亡率分别为29.7%、14.6%及2.1%;相应的3T3细胞凋亡率分别为4.3%、3.5%、2.6%. 结论 Res能通过诱导C6细胞凋亡而抑制其生长与增殖,但对3T3细胞无此作用.本研究为临床应用Res治疗脑胶质细胞瘤提供了实验依据. 相似文献
70.
无症状性炎性前列腺炎对血清PSA、fPSA的影响 总被引:3,自引:0,他引:3
目的 探讨无症状性炎性前列腺炎(NIH分类Ⅳ型)对血清PSA、fPSA的影响。方法 对比分析36例NIH分类Ⅳ型、42 例有症状性慢性前列腺炎(NIH分类ⅢA型)患者以及22例健康对照组的血清PSA、fPSA、fPSA/tPSA之间的差异。结果 血 清PSA、fPSA、fPSA/tPSA在Ⅳ型和ⅢA型前列腺炎患者间差异无显著性(P>0.05),但与正常对照组比较差异有显著性(P< 0.01)。结论 NIH分类Ⅳ型前列腺炎可引起血清PSA、fPSA升高。对无症状、高血清PSA患者行前列腺活检前,应考虑到患 Ⅳ型前列腺炎的可能。 相似文献