全文获取类型
收费全文 | 1326篇 |
免费 | 92篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 49篇 |
妇产科学 | 22篇 |
基础医学 | 172篇 |
口腔科学 | 48篇 |
临床医学 | 99篇 |
内科学 | 320篇 |
皮肤病学 | 39篇 |
神经病学 | 69篇 |
特种医学 | 118篇 |
外国民族医学 | 1篇 |
外科学 | 150篇 |
综合类 | 60篇 |
预防医学 | 37篇 |
眼科学 | 18篇 |
药学 | 117篇 |
中国医学 | 31篇 |
肿瘤学 | 83篇 |
出版年
2023年 | 11篇 |
2022年 | 29篇 |
2021年 | 50篇 |
2020年 | 101篇 |
2019年 | 67篇 |
2018年 | 55篇 |
2017年 | 47篇 |
2016年 | 33篇 |
2015年 | 53篇 |
2014年 | 55篇 |
2013年 | 48篇 |
2012年 | 46篇 |
2011年 | 44篇 |
2010年 | 38篇 |
2009年 | 49篇 |
2008年 | 61篇 |
2007年 | 32篇 |
2006年 | 27篇 |
2005年 | 29篇 |
2004年 | 32篇 |
2003年 | 26篇 |
2002年 | 21篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 17篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1980年 | 26篇 |
1979年 | 24篇 |
1978年 | 31篇 |
1977年 | 15篇 |
1976年 | 53篇 |
1975年 | 28篇 |
1974年 | 24篇 |
1973年 | 44篇 |
排序方式: 共有1437条查询结果,搜索用时 15 毫秒
1.
《Vaccine》2019,37(22):2952-2959
CD8+ T cells are known to control infections, but their role in preventing latent infection from establishing has not been thoroughly investigated.We hypothesized that a potent CD8+ T cell response patrolling the mucosal viral entry points could kill the first infected cells and thereby abrogate the infection before latency is established.To investigate this, replication deficient adenovirus serotype 5 vectors encoding murine γ-herpesvirus-68 CD8+ T cell epitopes linked to the T cell adjuvant Invariant chain, were developed. We show that intranasal vaccination of mice reduces the risk of establishment of latent infection from multiple intranasal ID50 challenges with murine γ-herpesvirus-68 by 81% per exposure at 14 days post vaccination. Protection waned over time, but immune responses were extended by heterologous prime-boost vaccination applied simultaneously intramuscularly and intranasally, and animals vaccinated 66 days prior to challenge showed a strong trend of long-term protection.Our data provides evidence that CD8+ T cells are able to protect against establishment of latent infection. Although the protective efficacy is difficult to maintain over time, this proof-of-concept study suggests a role for a CD8+ T cell arm in future vaccine strategies against latent human viral infections caused by pathogens such as HIV and multiple herpes virus. 相似文献
2.
目的建立东北苦菜Ixeris vesicolor DC.UPLC指纹图谱,并进行化学模式识别。方法东北苦菜甲醇提取物的分析采用CORTECS C18色谱柱(2.1 mm×150 mm,1.6μm);流动相0.1%磷酸水⁃乙腈,梯度洗脱;体积流量0.1 mL/min;检测波长(1~15 min,327 nm;15~50 min,360 nm);柱温35℃;进样量2μL。采用相似度分析和化学模式识别技术相结合的方法对其进行质量评价。结果10批样品指纹图谱中有19个共有峰,相似度均大于0.953。通过聚类分析将样品分成2类,主成分分析结果支持聚类分析结果,采用正交偏最小二乘法⁃判别分析筛选出了导致不同批次药材质量差异的3个共有峰,指认出2号峰(绿原酸)和12号峰(木犀草素)。结论该方法稳定可靠,可系统、全面地评价东北苦菜的药材质量。 相似文献
3.
目的探讨川芎⁃天麻配伍对川芎中川芎嗪、阿魏酸在大鼠脑内药动学的影响。方法18只大鼠随机分成川芎组、川芎⁃天麻(1∶0.25)组、川芎⁃天麻(1∶1)组,每组6只,建立血瘀型偏头痛模型。灌胃给药后,于大鼠脑内插入微透析探针,收集不同时间点脑透析液,UPLC⁃MS/MS法检测川芎嗪、阿魏酸含有量,绘制血药浓度⁃时间曲线,计算药动学参数。结果与单味药组比较,配伍组2种成分T1/2[川芎⁃天麻(1∶1)组阿魏酸除外]、MRT0~∞、Cmax、AUC0~∞升高(P<0.05,P<0.01);川芎⁃天麻(1∶0.25)组两者T1/2、MRT0~∞、AUC0~∞高于川芎⁃天麻(1∶1)组(P<0.05,P<0.01),川芎嗪Cmax降低(P<0.05)。结论天麻可提高川芎中川芎嗪、阿魏酸脑组织吸收程度,延长作用时间,减缓消除速率,增加蓄积,其作用强度与天麻剂量有关。 相似文献
4.
目的考察柴葛芩连汤联合常规治疗对湿热闭肺型小儿支气管肺炎患者的临床疗效。方法 137例患者随机分为对照组(68例)和观察组(69例),对照组给予常规治疗(吸氧、布洛芬、头孢美唑钠、喜炎平注射液),观察组在对照组基础上加用柴葛芩连汤,疗程10 d。检测临床疗效、恢复情况、血清炎症因子(CRP、IL-6、IL-8、TNF-α)、中医证候评分变化。结果观察组总有效率高于对照组(P<0.05),恢复情况(除X线全胸片消失时间外)更明显(P<0.05)。治疗后,2组炎症因子水平、中医证候评分降低(P<0.05),以观察组更明显(P<0.05)。结论柴葛芩连汤可缓解湿热闭肺型小儿支气管肺炎患者症状,其机制可能与下调血清CRP、IL-6、IL-8、TNF-α水平有关。 相似文献
5.
目的通过对急性心肌梗死后心力衰竭(HFMI)大鼠模型给药治疗,评估加味温胆汤对大鼠心肌能量代谢水平和心肌超微结构的影响。方法SD雄性大鼠随机分为两组,每组15只,造模组通过手术结扎冠状动脉左前降支造模,假手术组完成穿刺但并未结扎左前降支,术后饲养72 h,对两组大鼠进行慢性心衰评分并加以比较。将造模组15只大鼠分为3组,每组5只,中药组经口喂加味温胆汤,曲美他嗪组给予曲美他嗪溶液,对照组喂养生理盐水,给药4周后空腹抽取3组鼠尾静脉血,检测并比较各组大鼠心肌能量代谢因子:血清肌钙蛋白(cTnI)、心肌过氧化物酶体增殖物激活受体γ辅激活因子1α(PGC-1α)水平;进行超声检查,测定并比较左室射血分数(LVEF);采集心肌样本进行HE染色(核染)和Masson染色(纤染),对心肌超微结构完整性进行评分。结果治疗4周后,中药组、曲美他嗪组大鼠LVEF数值均较治疗前显著增加(P<0.05),对照组与治疗前相比降低(P<0.05),但治疗后中药组大鼠LVEF数值高于曲美他嗪组(P<0.05);与治疗前相比,3组大鼠血清cTnI、PGC-1α表达水平差异有统计学意义(P<0.05),中药组<曲美他嗪组<对照组;治疗4周后,3组大鼠心肌超微结构完整性评分比较差异也具有统计学意义(P<0.05),中药组<曲美他嗪组<对照组。结论加味温胆汤对急性心肌梗死后心力衰竭大鼠的心肌能量代谢具有促进作用,对心肌超微结构的完整性具有保护作用,并能有效改善大鼠的心功能。 相似文献
6.
ObjectiveThe aim of the present study was to evaluate the clinicopathological significance of phosphorylated nuclear factor-κB (pNF-κB) expression, and its impact on epithelial–mesenchymal transition and angiogenesis in colorectal cancer (CRC).MethodsWe carried out immunohistochemistry of pNF-κB on 261 human CRC tissues, and evaluated nuclear expression, regardless of cytoplasmic expression. We also investigated the correlation between pNF-κB expression and clinicopathological characteristics, survival, and epithelial–mesenchymal transition and angiogenesis-related markers in CRC.ResultspNF-κB was expressed in the nuclei of 164 of the 261 CRC tissues (62.8%). Furthermore, pNF-κB was significantly correlated with frequent perineural invasion, lymph node metastasis, and higher pTNM stage. However, there was no significant correlation between pNF-κB expression and other clinicopathological parameters. Among the epithelial–mesenchymal transition markers examined, SNAIL expression was significantly correlated with pNF-κB expression (P = 0.001) but E-cadherin expression was not. CRC with pNF-κB expression had significantly higher SIRT1 expression levels and hypoxia-inducible factor-1α expression levels than CRC without pNF-κB expression (P < 0.001 and P < 0.001, respectively). However, there was no correlation between the expression levels of pNF-κB and VEGF. pNF-κB expression was significantly correlated with worse overall and recurrence-free survival rates (P < 0.001 and P < 0.001, respectively).ConclusionpNF-κB expression was significantly correlated with aggressive tumor behaviors and worse survival rates. Furthermore, pNF-κB expression may affect tumor invasion and progression through SNAIL-related epithelial–mesenchymal transition and SIRT1- and hypoxia-inducible factor-1α-induced angiogenesis. 相似文献
7.
Microglia, as the resident immune cells in the central nervous system, play important roles in regulating neuronal processes, such as neural excitability, synaptic activity, and apoptotic cell clearance. Growth factors can activate multiple signaling pathways in central nervous system microglia and can regulate their immune effects, but whether growth factors can affect the morphological characteristics and ultrastructure of microglia has not been reported. After microinjecting 300 nL of a growth factor cocktail, including 10 μg/mL epidermal growth factor, 10 μg/mL basic fibroblast growth factor, 10 μg/mL hepatocyte growth factor and 10 μg/mL insulin-like growth factor into adult rat cortex, we found that the number of IBA1-positive microglia around the injection area increased significantly, indicating local activation of microglia. All CD68-positive labeling co-localized with IBA1 in microglia. Cell bodies and protrusions of CD68-positive cells were strongly attached to or were engulfing neurons. Characteristic huge phagosomes were observed in activated phagocytes by electron microscopy. The phagosomes generally included non-degraded neuronal protrusions and mitochondria, yet they contained no myelin membrane or remnants, which might indicate selective phagocytosis by the phagocytes. The remnant myelin sheath after phagocytosis still had regenerative ability and formed "myelin-like" structures around phagocytes. These results show that microinjection of a growth factor cocktail into the cerebral cortex of rodents can locally activate microglia and induce selective phagocytosis of neural structures by phagocytes. The study was approved by the Institute of Laboratory Animal Science, Beijing Institute of Basic Medical Sciences(approval No. IACUC-AMMS-2014-501) on June 30, 2014. 相似文献
8.
9.
10.