全文获取类型
收费全文 | 69556篇 |
免费 | 6286篇 |
国内免费 | 5078篇 |
专业分类
耳鼻咽喉 | 400篇 |
儿科学 | 722篇 |
妇产科学 | 876篇 |
基础医学 | 8725篇 |
口腔科学 | 1192篇 |
临床医学 | 9328篇 |
内科学 | 10574篇 |
皮肤病学 | 782篇 |
神经病学 | 3654篇 |
特种医学 | 2416篇 |
外国民族医学 | 41篇 |
外科学 | 7085篇 |
综合类 | 12013篇 |
现状与发展 | 17篇 |
一般理论 | 2篇 |
预防医学 | 4301篇 |
眼科学 | 1826篇 |
药学 | 7386篇 |
74篇 | |
中国医学 | 3720篇 |
肿瘤学 | 5786篇 |
出版年
2024年 | 226篇 |
2023年 | 1197篇 |
2022年 | 2847篇 |
2021年 | 3596篇 |
2020年 | 2608篇 |
2019年 | 2383篇 |
2018年 | 2385篇 |
2017年 | 2047篇 |
2016年 | 2057篇 |
2015年 | 3143篇 |
2014年 | 3945篇 |
2013年 | 3290篇 |
2012年 | 4825篇 |
2011年 | 5688篇 |
2010年 | 3304篇 |
2009年 | 2502篇 |
2008年 | 3463篇 |
2007年 | 3527篇 |
2006年 | 3628篇 |
2005年 | 3481篇 |
2004年 | 2249篇 |
2003年 | 2203篇 |
2002年 | 1834篇 |
2001年 | 1692篇 |
2000年 | 1768篇 |
1999年 | 1966篇 |
1998年 | 1251篇 |
1997年 | 1342篇 |
1996年 | 1007篇 |
1995年 | 889篇 |
1994年 | 768篇 |
1993年 | 489篇 |
1992年 | 602篇 |
1991年 | 520篇 |
1990年 | 446篇 |
1989年 | 393篇 |
1988年 | 324篇 |
1987年 | 283篇 |
1986年 | 249篇 |
1985年 | 173篇 |
1984年 | 102篇 |
1983年 | 71篇 |
1982年 | 38篇 |
1981年 | 52篇 |
1980年 | 28篇 |
1979年 | 38篇 |
1963年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study is to investigate the effect of FK506 on expression of hepatocyte growth factor (HGF) in rats' spinal cord following peripheral nerve injury and to elucidate the mechanisms for neuroprotective property of FK506. Fifty male rats were randomly divided into normal group, injury group and treatment group. Models of peripheral nerve injury were established by bilateral transection of sciatic nerve 0.5 cm distal to piriform muscle. Then the treatment group received subcutaneous injection of FK506 (1 mg/kg) at the back of neck, while the injury group was given 0.9% saline. The L4-6 spinal cords were harvested at various time points after the surgery. Western blotting and immunofluorescent staining were used to detect the level and position of HGF in spinal cord. Immunofluorescent staining showed that HGF-positive neurons were located in anterior horn, intermediate zone and posterior horn of gray matter in normal spinal cord. Western blotting revealed that there was no significant difference in the expressions of HGF between the injury group and the normal group, while the expression of HGF was significantly higher in the treatment group than in the injury group 7 and 14 days after surgery. It is suggested that peripheral nerve injury does not result in up-regulation of the expression of HGF in spinal cord, while FK506 may induce high expression of endogenous HGF after injury thereby protecting neurons and promoting axonal outgrowth. 相似文献
992.
目的探讨抑癌基因BCSC-1对肿瘤的治疗作用。方法制备重组腺病毒Ad5-BCSC-1。用CellTiter 96 A-queous细胞增殖单一溶液检测试剂盒检测细胞增殖。肿瘤体内注射Ad5-BCSC-1,以注射Ad5-egfp或PBS作为对照,1周后重复注射,再2周后处死小鼠,称瘤重。结果Ad5-BCSC-1感染的CNE-2L2细胞的生长明显减慢,细胞在培养中聚集成大细胞团块。注射PBS、Ad5-egfp和Ad5-BCSC-1的小鼠CNE-2L2肿瘤的平均瘤重分别为(2·28±0·73)、(2·07±0·40)和(0·58±0·32)g。Ad5-BCSC-1组显著低于PBS和Ad5-egfp组(P<0·05)。结论瘤体内注射Ad5-BCSC-1能抑制CNE-2L2肿瘤的生长,提示BCSC-1基因治疗对BCSC-1基因缺失或表达低下的肿瘤可能有治疗作用。 相似文献
993.
Background Gemcitabine plus cisplatin is a standard treatment for stages IIIB and IV nonsmall cell lung cancer (NSCLC). This randomized phase Ⅱ study evaluated a 3-week versus a 4-week schedule of gemcitabine-cisplatin as first line treatment for Chinese patients with advanced NSCLC.
Methods Patients were randomized to receive cisplatin 75 mg/m^2 on day 1 plus either gemcitabine 1250 mg/m^2 on days 1 and 8 of a 21-day cycle (3-week group) or gemcitabine 1000 mg/m2 on days 1,8 and 15 of a 28-day cycle (4-week group).
Results One hundred patients were enrolled in this study. The response rate was 24% (12/51 patients) in the 3-week group and 27% (13/49 patients) in the 4-week group. There were no statistically significant differences between the two treatment groups in survival (hazard ratio: 1.19; 95% CI: 0.68-2.09) with a median survival of 12.1 months and 13.8 months in the 3-week group and the 4-week group respectively. The rate of grade 3/4 toxicity in the 3-week group was 55% compared with 86% in the 4-week group (P=0.001). The difference in the incidence of grade 3/4 haematological toxicities did not reach statistical significance (3-week: 37%, 4-week: 57%), however grade 3/4 drug related neutropenia (3-week: 27%, 4-week: 51%) and thrombocytopenia (3-week: 8%, 4-week: 31%) were significantly lower in the 3-week group. Grade 3/4 nonhaematological toxicities were less in the 3-week group (33% cf 63%; P=0.005).
Conclusions The differences in the efficacy endpoints were all in favour of the 4-week schedule of gemcitabine plus cisplatin, however these differences did not reach statistical significance. Fewer grade 3/4 toxicities were observed in the 3-week group compared with the 4-week group. 相似文献
Methods Patients were randomized to receive cisplatin 75 mg/m^2 on day 1 plus either gemcitabine 1250 mg/m^2 on days 1 and 8 of a 21-day cycle (3-week group) or gemcitabine 1000 mg/m2 on days 1,8 and 15 of a 28-day cycle (4-week group).
Results One hundred patients were enrolled in this study. The response rate was 24% (12/51 patients) in the 3-week group and 27% (13/49 patients) in the 4-week group. There were no statistically significant differences between the two treatment groups in survival (hazard ratio: 1.19; 95% CI: 0.68-2.09) with a median survival of 12.1 months and 13.8 months in the 3-week group and the 4-week group respectively. The rate of grade 3/4 toxicity in the 3-week group was 55% compared with 86% in the 4-week group (P=0.001). The difference in the incidence of grade 3/4 haematological toxicities did not reach statistical significance (3-week: 37%, 4-week: 57%), however grade 3/4 drug related neutropenia (3-week: 27%, 4-week: 51%) and thrombocytopenia (3-week: 8%, 4-week: 31%) were significantly lower in the 3-week group. Grade 3/4 nonhaematological toxicities were less in the 3-week group (33% cf 63%; P=0.005).
Conclusions The differences in the efficacy endpoints were all in favour of the 4-week schedule of gemcitabine plus cisplatin, however these differences did not reach statistical significance. Fewer grade 3/4 toxicities were observed in the 3-week group compared with the 4-week group. 相似文献
994.
胰高血糖素样肽-2对放射损伤小鼠肠上皮恢复的影响 总被引:6,自引:2,他引:6
目的:探讨胰高血糖素样肽-2对放射损伤小鼠肠上恢复的影响。方法:昆明种小鼠经8Gy^60 Co γ射线一次性全身照射后随机分为放射损伤对照组和胰高血糖素样肽-2处理组,检测小肠粘膜组织DNA和蛋白含量,光镜和扫描电镜观察肠上皮形态结构变化。结果:放射损伤小肠粘膜组织DNA和蛋白含量降低,肠绒毛高度下降、数量减少,部分绒毛顶端有糜烂缺损;胰高血糖素样肽-2处理可使肠粘膜组织DNA和蛋白含量降低,肠绒毛增长、数量增多,糜烂发生不明显。结论:胰高血糖素样肽-2可促进放射损伤小鼠肠上皮的恢复。 相似文献
995.
幽门螺杆菌感染对胃粘膜病变作用的五年随访观察 总被引:11,自引:1,他引:11
目的 评价5年随访根除幽门螺杆菌(Hp)感染对胃粘膜病变的作用。方法 采用前瞻性队列研究方法,病例为上海7家企业单位在我院定点体检进行胃镜检查的病人。入选时间为1993年7月至1994年6月,部分病人有中上腹不适,胃镜及病理检查确诊为慢性胃炎的病人作为入选病例。入选时确定Hp感染状态,阳性病人根据自愿原则或采用根除Hp感染治疗,或采用对症治疗。阴性组仅在有消化不良症状时采用对症治疗。全部对象跟踪随访5年。结果 入选时30例Hp阴性,45例Hp阳性。结束随访时,24例阴性无变化(另3例失访,1例变为阳性,2例可疑),作为对照组,45例Hp阳性。结束随访时,24例阴性无变化(另3例失访,1例变为阳性,2例可疑),作为对照组。45例阳性病人中,1例失访,16例经抗Hp感染治疗结束4周后转阴,作为Hp阴性观察组;28例仍为Hp阳性,作为Hp阳性观察组。对照组仅17%-33%的病人炎症有进展,Hp阳性观察组,炎症加重的病人占43%-57%,Hp阴性观察组,50%的病人肠化生加重,但50%-67%的病人无明显变化;Hp阳性观察组肠化生加重的病人增至43%-57%,而Hp阴性观察组无一例加重,75%的病人维持原状。结论 根除Hp感染不仅可减轻病人的炎症程度,同时能阻止肠上皮化生的发展。 相似文献
996.
绝经后妇女骨丢失与1,25-二羟维生素D的相关性研究 总被引:5,自引:2,他引:5
目的研究随增龄和绝经发生的骨化三醇1,25(OH)2D活性和/或数量降低与骨量丢失的相关性及其影响因素,以阐明绝经后骨质疏松症的病因机理以用于指导临床防治.方法应用放免法测定了绝经后骨质疏松症妇女57例和绝经后非骨质疏松症妇女37例的血清1,25-二羟维生素D(1,25(OH)2D)、25-羟维生素D(25(OH)D)、甲旁腺素(PTH)、雌激素(E2)水平,ELISA法测定尿脱氧吡啶酚与肌酐比值等骨代谢相关指标,并进行病例对照分析.结果绝经后骨质疏松妇女血清1,25(OH)2D和25(OH)D含量分别为18 pg/ml±6pg/ml和32 ng/ml±9 ng/ml,非骨质疏松组分别为31 pg/ml±14 pg/ml和46 pg/ml±17 ng/ml, 骨质疏松妇女的血清1,25(OH)2D和25(OH)D含量明显低于非骨质疏松妇女,雌激素水平也明显降低,但PTH和Dpd/Cr水平则明显升高(P<0.01).对于绝经后妇女,L2~4的骨密度值(BMD)与血清1,25(OH)2D含量存在高度相关(r=0.693,P<0.001), BMD值的变异中有48%可以用血清1,25(OH)2D水平的变化来解释.此外,血清1,25(OH)2D与25(OH)D的相关关系密切(r=0.511, P<0.001),两者存在底物依赖合成关系.结论血清1,25(OH)2D水平与骨量值明显相关.年龄的增长,绝经年限的延长和绝经引起雌激素水平的下降,导致了血清1,25(OH)2D 水平下降,并伴有继发性PTH升高,是绝经后妇女骨量丢失加速的重要病理生理之一. 相似文献
997.
孕妇外周血血浆胎儿DNA的检测 总被引:3,自引:0,他引:3
目的:建立可靠有效的检测孕妇血浆胎儿DNA的方法,探讨其在非创伤性产前诊断中的价值。方法:采用引物引伸预扩增(PEP)法及巢式PCR技术对65例孕妇外周血血浆DNA进行正常男性SRY基因检测。结果:单用巢式PCR技术和联合应用PEP,PCR技术对怀男胎的孕妇血中SRY基因检出率分别为65.2%(30/46)和89.1%(41/46),两组差异有极显著性,对怀女胎孕妇血中SRY基因的未检出率为78.9%(15/19)和94.7%(18/19),两组差异无显著性。结论:应用PEP法可对胎儿DNA进行全基因组扩增使DNA模板量增加,并使继后的PCR技术检测SRY基因的敏感性明显提高,PEP法是解决母血中胎儿细胞数量太少的途径之一,孕妇血浆中胎儿DNA可成为非创伤性产前诊断的胎儿物质来源。 相似文献
998.
目的:评价足月新生儿营养状况及探讨出生体重与营养不良的关系。方法:连续测定了200例正常孕妇的足月单胎新生儿的营养指标。结果:以“三褶”及“三褶”及“二围”均≤第10百分位数为新生儿营养不良,在165例适龄儿中有14例(8.5%)为营养不良儿,15例小于胎龄儿中8例(53.3%)为营养不良儿。结论:“三褶”及“二围”是评价新生儿营养状况的简便,实用且准确的指标,由于小于胎龄儿与营养不良儿的出生结局及预后并不完全一致,故准确评估新生儿营养状况以判断胎儿生长及结局非常重要。 相似文献
999.
目的 :探讨幽门螺杆菌细胞毒素相关基因蛋白 (CagA)抗体与消化性溃疡和慢性胃炎的关系。方法 :对132例消化性溃疡和慢性胃炎Hp幽门螺杆菌阳性的 118例病例 ,用ELISA方法进行CagA抗体检测。结果 :10 9例消化性溃疡中 ,CagA抗体阳性 90例 ,阳性率 82 .6 % ;9例慢性胃炎中 ,CagA抗体阳性 5例 ,阳性率 5 5 .6 %。消化性溃疡组CagA阳性率明显高于慢性胃炎组 (P <0 .0 1)。结论 :CagA抗体检测在消化性溃疡中有一定意义 相似文献
1000.
肝郁证T、B淋巴细胞活性改变及疏肝治疗影响的实验研究 总被引:12,自引:0,他引:12
为探讨肝郁证机特异性免疫应答的变化及疏肝治疗的影响,采用夹尾应激加肾上腺素注射法复制肝郁证模型,观察分别代表细胞免疫与体液免疫功能的T、B淋巴细胞活性变化、血液IgG、IgM的水平及疏肝解郁基本方剂柴胡疏肝散对它们的影响,结果肝郁证模型大鼠T、B淋巴细胞转化率显著升高,IgM水平显著降低,通过灌服柴胡疏肝散可明显预防前者的升高,而对后者的降低无明显影响,认为肝郁证淋巴细胞活性增强,IgM水平降低,疏肝治疗通过降低淋巴细胞活性而发挥作用。 相似文献