全文获取类型
收费全文 | 6666篇 |
免费 | 237篇 |
国内免费 | 218篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 76篇 |
妇产科学 | 80篇 |
基础医学 | 1208篇 |
口腔科学 | 77篇 |
临床医学 | 327篇 |
内科学 | 751篇 |
皮肤病学 | 52篇 |
神经病学 | 1299篇 |
特种医学 | 61篇 |
外科学 | 208篇 |
综合类 | 675篇 |
预防医学 | 493篇 |
眼科学 | 67篇 |
药学 | 1178篇 |
1篇 | |
中国医学 | 225篇 |
肿瘤学 | 293篇 |
出版年
2024年 | 7篇 |
2023年 | 34篇 |
2022年 | 57篇 |
2021年 | 108篇 |
2020年 | 71篇 |
2019年 | 84篇 |
2018年 | 76篇 |
2017年 | 95篇 |
2016年 | 117篇 |
2015年 | 110篇 |
2014年 | 225篇 |
2013年 | 304篇 |
2012年 | 273篇 |
2011年 | 342篇 |
2010年 | 252篇 |
2009年 | 286篇 |
2008年 | 288篇 |
2007年 | 258篇 |
2006年 | 250篇 |
2005年 | 236篇 |
2004年 | 212篇 |
2003年 | 183篇 |
2002年 | 178篇 |
2001年 | 149篇 |
2000年 | 127篇 |
1999年 | 119篇 |
1998年 | 146篇 |
1997年 | 138篇 |
1996年 | 124篇 |
1995年 | 125篇 |
1994年 | 110篇 |
1993年 | 100篇 |
1992年 | 93篇 |
1991年 | 124篇 |
1990年 | 110篇 |
1989年 | 104篇 |
1988年 | 93篇 |
1987年 | 114篇 |
1986年 | 139篇 |
1985年 | 218篇 |
1984年 | 227篇 |
1983年 | 178篇 |
1982年 | 149篇 |
1981年 | 142篇 |
1980年 | 109篇 |
1979年 | 53篇 |
1978年 | 30篇 |
1977年 | 32篇 |
1976年 | 8篇 |
1973年 | 4篇 |
排序方式: 共有7121条查询结果,搜索用时 0 毫秒
31.
Bahram Dalir-Naghadeh Siamak Asri-Rezaei Naser Alidady 《Comparative clinical pathology》2006,15(3):149-153
Odds ratio was used to evaluate relationship between sepsis in cattle less than 1 year old and mastitis in cows and erythrocyte glutathione peroxides (GSH-PX) activity as an indicator of selenium status. Data were from 178 blood samples collected from referred cases to Urmia University, Veterinary Teaching Hospital. Low activity of GSH-PX was significantly associated with higher odds of developing sepsis (P=0.005) in young cattle and mastitis (P=0.044) in adult cows. The odds ratios for the low activity of GSH-PX on incidence of sepsis and mastitis were 4.74 and 3.95, respectively. Selenium deficiency was associated with sepsis in young cattle and mastitis in cows, i.e., cattle with low activity of erythrocyte GSH-PX were at increased risk of sepsis and mastitis. 相似文献
32.
33.
34.
研究了纳米硒和亚硒酸钠对断奶仔猪肝脏谷胱甘肽过氧化物酶和脱碘酶活性的影响。将纳米硒和亚硒酸钠2种硒源分别以0.1、0.2、0.3、0.4、0.5、1.0 mg/kg 6个硒水平添加到基础日粮中,配制成12种试验日粮,基础日粮作对照,饲养“杜长大”断奶仔猪(8.3 kg左右)。结果表明:以亚硒酸钠形式添加的硒浓度为1.0 mg/kg时,仔猪生长性能和GSH-Px活性显著低于0.2~0.4 mg/kg硒添加水平(P<0.05),纳米硒添加浓度为1.0 mg/kg,仔猪生长性能和GSH-Px活性仍然保持在高峰平台;硒源添加浓度为0.10~0.40 mg/kg时,两种硒源对GSH-Px活性的影响无显著差异(P>0.05);在0.50和1.0 mg/kg硒添加水平上,纳米硒组GSH-Px活性显著高于亚硒酸钠组(P<0.05)。基础日粮组肝脏脱碘酶活性显著低于各硒源的添加水平(P<0.05),硒源和硒添加水平对脱碘酶活性没有显著影响(P>0.05)。上述结果提示:纳米硒的Weinberg剂量-效应的最适剂量范围宽于亚硒酸钠。 相似文献
35.
Anti-human thyroid peroxidase and anti-human thyroglobulin antibodies present no cross-reactivity on recombinant peptides. 下载免费PDF全文
Thyroglobulin (Tg) and thyroid peroxidase (TPO) are two antigens largely recognized by the sera from patients with autoimmune thyroid disease (AITD). Recently, the complete mapping of both antigens was established with rabbit polyclonal antibodies by the use of recombinant proteins expressed in prokaryotic vector. Several investigators have argued for the existence of a cross-reactivity of some hetero- and autologous antibodies versus these two proteins. In the present study, using rabbit polyclonal antibody, mouse polyclonal antibody and autoimmune antibody (aAb), we observed no common epitope on human Tg (hTg) and human TPO (hTPO). 相似文献
36.
A J Beitz 《Neuroscience》1982,7(11):2753-2768
The sites of origin of brain stem enkephalin and substance P projections to the rodent nucleus raphe magnus were studied utilizing the combined horseradish peroxidase retrograde transport-peroxidase-antiperoxidase immunohistochemical technique. Several brain stem areas were found to contain both enkephalin- and substance P-like immunoreactive double labeled neurons following injection of horseradish peroxidase into the raphe magnus. Nuclei providing both enkephalin and substance P inputs to the raphe magnus include the nucleus reticularis paragigantocellularis, the nucleus cuneiformis, the nucleus solitarius and the trigeminal subdivision of the lateral reticular nucleus. Enkephalin projections to the raphe magnus were also found to originate from the dorsal parabrachial nucleus, the nucleus reticularis gigantocellularis pars α and from an area which corresponds to the A5 group of Dahlström &; Fuxe. Additional neurons containing substance P-like immunoreactivity and horseradish peroxidase reaction product were identified in the superior central raphe nucleus and the nucleus pontis oralis. The midbrain periaqueductal gray contributes very few enkephalin and substance P fibers to the raphe magnus.The nucleus raphe magnus is a key structure in the intrinsic analgesia system and it has also been implicated in other diverse and non-nonciceptive functions. The present study identifies several brain stem sites which provide enkephalin and substance P input to this raphe nucleus. Several of these nuclei have been implicated in central analgesic mechanisms or in non-nociceptive autonomic functions. The present investigation raises the possibility that these brain stem regions may modulate neuronal activity in the raphe magnus via enkephalin or substance P projections and thus influence the involvement of the raphe magnus in both opiate related mechanisms of pain control and non-nociceptive functions. 相似文献
37.
目的:探讨云芝多糖(CVPS)-CVPS-B对氧化修饰低密度脂蛋白(ox-LDL)诱导的巨噬细胞(RAW264.7)单核细胞趋化蛋白-1(MCP-1)mRNA表达的影响,及对核因子-κB(NF-κB)和细胞内谷胱甘肽(GSH)的调控作用。方法:应用反转录聚合酶链反应(RT-PCR)测定RAW264.7细胞MCP-1 mRNA的表达;凝胶滞留法(EMSA)测定NF-κB的结合活性;荧光分光光度法测定细胞内GSH的活性。结果:CVPS-B呈剂量依赖性抑制ox-LDL诱导的RAW264.7细胞MCP-1 mRNA的表达。应用GSH 特异性消耗剂buthionine-[S,R]-sulfoximine (BSO),ox-LDL不能诱导RAW264.7细胞MCP-1 mRNA的表达。CVPS-B抑制ox-LDL诱导RAW264.7细胞内GSH活性下降。CVPS-B呈剂量依赖性抑制 ox-LDL诱导的RAW264.7细胞NF-κB活性;在完全消耗GSH的RAW264.7细胞,ox-LDL不能诱导NF-κB的活性。结论:CVPS-B可抑制ox-LDL诱导RAW264.7细胞MCP-1 mRNA的表达;其抑制作用可能通过GSH/NF-κB的调控。 相似文献
38.
Abdolamir Allameh Nargess Maleklou Mehryar Zargari Mohammad Hossein Sanati 《Neuroscience letters》2008
Recently we reported that antioxidant system in brain and spinal cord in experimental autoimmune encephalomyelitis (EAE) mice is mainly affected at early stages of the disease [M. Zargari, A. Allameh, M.H. Sanati, T. Tiraihi, S.H. Lavasani, O. Emadyan, Relationship between the clinical scoring and demyelination in central nervous system with total antioxidant capacity of plasma during experimental autoimmune encephalomyelitis development in mice, Neurosci. Lett. 412 (2007), 24–28]. The aim of the present study was to investigate the role of uric acid (UA) on antioxidant system in liver and plasma of EAE mice. EAE was induced in C57/BL6 mice (n = 60), followed by i.p. administration of UA (10 mg/kg BW) in 30 mice at three distinct clinical stages (A: prior to onset, B: after onset, C: after development of EAE). Livers were removed and processed for measurement of lipid peroxidation products, reduced glutathione (GSH), and glutathione S-transferase (GST) and total antioxidant capacity of plasma (FRAP). The results showed that lipid peroxidation products in liver of EAE mice was increased significantly (∼85%) as compared to normal. UA administration to EAE mice caused a significant suppression of liver lipid peroxidation products (∼45%) at early stages (A and B). There was an inverse relationship between lipid peroxidation and cellular GSH in liver. GSH was significantly depleted in mice liver during the EAE progression, but it was recovered (∼29%) when UA was injected before the onset of the disease (groups A and B). Plasma total antioxidant capacity was significantly decreased during the development of EAE, however it was subsided in mice treated with UA as compared to the corresponding controls (21%) in groups A and B. Elevated liver GST as a result of EAE induction was reversed in mice treated with UA particularly in groups A and B. These results indicate that hepatic glutathione system, particularly GST plays a major role in modulation of oxidative damages to central nervous system (CNS) during EAE induction. The positive response of antioxidant system to UA administration in EAE mice was corroborated with improvement of clinical manifestation of the animals. 相似文献
39.
猫前脑和脑干向中缝背核的纤维投射 总被引:4,自引:0,他引:4
中缝背核在针剌镇痛过程中起重要作用。本文用HRP法,对猫前脑和脑干向中缝背核的纤维投射,作了进一步的研究。 HRP注入中缝背核吻侧部后,在前脑双侧先导回皮质和梨状前区皮质V层出现较多被标记的锥体细胞;缰外侧核出现较密集且形态不一的标记细胞;下丘脑各区(视前区、外侧区、内侧区和后区)也出现散在的标记细胞。 HRP注入中缝背核尾侧部后,除前脑出现标记细胞的部位与HRP注入吻侧部者相同外,在脑干中脑导水管周围灰质、蓝斑,其他中缝核(中央上核,中缝线形核和中缝大核)、臂旁内、外侧核及脑干网状结构等处,也观察到标记细胞。结果表明前脑皮质、缰外侧核、下丘脑各区均有纤维直接投射到中缝背核。中缝背核也接受来自中脑水管周围灰质、蓝斑、其他中缝核等核团的纤维投射;中缝背核吻侧部和尾侧部的传入投射,存在一定的局部定位关系,即中缝背核吻侧部只接受来自前脑的纤维投射,其尾侧部既接受来自前脑的纤维投射,也接受来自脑干的纤维投射。 相似文献
40.
J. Leveteau I. Andriason P. Mac Leod 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1992,89(1):93-104
Summary Whether or not the frog olfactory neuroreceptor cells project bilaterally to the olfactory bulb is still a debated question. We therefore decided to ascertain whether bilateral projections of the primary olfactory input exist and if so to investigate their extent. Reproducible extracellular bilateral bulbar potentials were recorded in the frog following electrical stimulation of dorsal or ventral olfactory nerve bundles. The general features of the contralateral evoked responses were very similar to those of the ipsilateral response. The contralateral response disappeared after transection of the rostral part of the olfactory interbulbar adhesion but not following transection of the habenular or anterior commissures. Horseradish peroxidase labelling showed that the fiber terminations of the olfactory nerve bundle was not restricted to the ipsilateral olfactory bulb but included the medial aspects of the contralateral bulb. The intertelencephalic sections increased the magnitude of the ipsilateral evoked responses. Olfactory bulb isopotential maps revealed a rough topographical correspondence between the olfactory neuroepithelium and bulb along the medio-lateral axis as well as along the dorso-ventral axis. In addition, a projection of the medial and central part of the olfactory sac to the medial part of the contralateral olfactory bulb through the interbulbar adhesion was confirmed. These findings suggest first, that the fibers from the neuro-receptors located in either the ventral or the dorsal olfactory mucosae project to both olfactory bulbs, and second, that the left and right bulbs exert a constant inhibition on each other via the habenular commissure.Abbreviations AON
anterior olfactory nucleus
- ax
olfactory neuroreceptor axon
- BA
bulbar adhesion
- DI
latero-dorsal olfactory nerve bundle
- DII
centro-dorsal olfactory nerve bundle
- DIII
mediodorsal olfactory nerve bundle
- EPL
external plexiform layer
- GL
glomerular layer
- gl
glomerulus
- GRL
granular cell layer
- MOB
main olfactory bulb
- m
mitral cell
- MBL
mitral cell body layer
- ON
olfactory nerve
- V
lateral ventricule
- VI
latero-ventral ol-factory nerve bundle
- VII
centro-ventral olfactory nerve bundle
- VIII
medio-ventral olfactory nerve bundle
- VN
vomero-nasal nerve 相似文献