全文获取类型
收费全文 | 36176篇 |
免费 | 3490篇 |
国内免费 | 2699篇 |
专业分类
耳鼻咽喉 | 251篇 |
儿科学 | 472篇 |
妇产科学 | 264篇 |
基础医学 | 3767篇 |
口腔科学 | 577篇 |
临床医学 | 5117篇 |
内科学 | 4808篇 |
皮肤病学 | 336篇 |
神经病学 | 1549篇 |
特种医学 | 1003篇 |
外国民族医学 | 17篇 |
外科学 | 2918篇 |
综合类 | 7890篇 |
现状与发展 | 14篇 |
预防医学 | 2912篇 |
眼科学 | 942篇 |
药学 | 4221篇 |
43篇 | |
中国医学 | 2705篇 |
肿瘤学 | 2559篇 |
出版年
2024年 | 139篇 |
2023年 | 606篇 |
2022年 | 1503篇 |
2021年 | 1858篇 |
2020年 | 1484篇 |
2019年 | 1115篇 |
2018年 | 1143篇 |
2017年 | 1185篇 |
2016年 | 1026篇 |
2015年 | 1674篇 |
2014年 | 2169篇 |
2013年 | 1999篇 |
2012年 | 3074篇 |
2011年 | 3226篇 |
2010年 | 2269篇 |
2009年 | 1898篇 |
2008年 | 2222篇 |
2007年 | 2238篇 |
2006年 | 2019篇 |
2005年 | 1752篇 |
2004年 | 1235篇 |
2003年 | 1124篇 |
2002年 | 925篇 |
2001年 | 802篇 |
2000年 | 684篇 |
1999年 | 644篇 |
1998年 | 363篇 |
1997年 | 366篇 |
1996年 | 289篇 |
1995年 | 242篇 |
1994年 | 232篇 |
1993年 | 137篇 |
1992年 | 127篇 |
1991年 | 147篇 |
1990年 | 114篇 |
1989年 | 92篇 |
1988年 | 67篇 |
1987年 | 57篇 |
1986年 | 44篇 |
1985年 | 25篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
361.
目的:研究蛋白激酶A(PKA)对微管相关蛋白tau的磷酸化作用。方法:采用免疫印迹技术,利用位点特异性、磷酸化依赖的tau蛋白抗体,检测PKA对tau蛋白磷酸化作用的位点特异性及磷酸化作用动力学。用双倒数作图,计算PKA催化tau磷酸化以及各个位点磷酸化的Km值,并结合培养细胞的实验,研究PKA对tau蛋白磷酸化作用的位点特异性。结果:PKA催化tau蛋白在Ser214,Ser262,Ser409三个位点磷酸化,而且各位点磷酸化作用的Km值不同,PKA对Ser214的Km值最低,即对Ser214位点的亲和性最高,催化其磷酸化的能力最强。在细胞实验中,也显示了PKA引起Ser214位点的磷酸化最明显。结论:PKA催化tau蛋白在Ser214,Ser262,Ser409三个位点磷酸化,其中Ser214是PKA催化tau磷酸化反应的最好位点。 相似文献
362.
子宫颈癌的筛查及进展 总被引:2,自引:0,他引:2
子宫颈癌是最常见的妇科恶性肿瘤之一,发病率在女性恶性肿瘤中居第二位,仅次于乳腺癌。据世界范围统计,每年约有46.6万新发病例,80%发生在发展中国家,其中约13万在中国。在发达国家,由于有较完善的宫颈癌筛查制度,其发病率和死亡率巳大幅度下降;在发展中国家,宫颈癌的筛查工作尚不完善,发病率是发达国家的6倍,并且80%的患者确诊时巳发展为浸润癌。我国于50年代开始子宫颈癌普查,通过历年普查,年龄调整死亡率由70年代的10.7/10万下降到90年代的2.89/10万,下降了63.84%,但在一些高发区,子宫颈癌的发病率与死亡率仍居高不下。 相似文献
363.
The long-term impact of 2-3 years of hormone replacement therapy on cardiovascular mortality and atherosclerosis in healthy women. 总被引:1,自引:0,他引:1
OBJECTIVE: The effect of hormone replacement therapy (HRT) on cardiovascular risk is intensely debated. The aim of this study was to investigate the long-term effects of HRT given for a few years on all-cause and cardiovascular mortality and the severity of atherosclerosis. METHODS: This analysis was based on a cohort of 1,458 postmenopausal women (55.8 +/- 6.1 years old) who previously participated in a number of randomized, placebo-controlled, clinical trials assessing the efficacy of 2-3 years of therapy with various estrogen plus progestin combinations for preventing bone loss. Women were followed on average for 9.8 years and came for a follow-up visit. Outcome variables were all-cause and cardiovascular mortality and the severity of atherosclerosis, as estimated by semi-quantitative scoring of vascular calcification in the lumbar aorta on lateral radiographs. RESULTS: A total of 174 women died during the observation period. All-cause mortality was decreased by 30% in the HRT+ group compared with the HRT- group (hazard ratio (HR) 0.70; 95% confidence interval (CI) 0.50-0.97) after adjusting for age, body mass index and smoking. Under the same conditions, similar results characterized mortality from cardiovascular disease (n = 61 deaths; 35.1% of all deaths) and coronary heart disease (n = 39 deaths; 22.4% of all deaths), which were decreased by 46% (HR 0.54, 95% CI 0.29-0.98, p = 0.045) and 53% (HR 0.47, 95% CI 0.21-1.03, p = 0.062), respectively. Furthermore, the mean severity score of aortic calcification at follow-up was significantly lower in hormone-treated compared to non-treated women (p < 0.0001). CONCLUSION: Women who receive 2-3 years of HRT after menopause do not have increased all-cause mortality, and results of the present study suggest relative cardiovascular benefits compared to those who had not used hormones. 相似文献
364.
更昔洛韦治疗特发性血小板减少性紫癜应用指征 总被引:1,自引:0,他引:1
目的探讨更昔洛韦(GCV)治疗人巨细胞病毒(HCMV)感染相关的特发性血小板减少性紫癜的(ITP)应用指征。方法选择血清HCMV DNA PCR和(或)HCMV IgM检测呈阳性ITP患儿46例,采用逆转聚合酶扩增反应(RT-PCR)检测巨核系祖细胞中HCMV晚期抗原mRNA,并行GCV治疗,判定其疗效及应用指征。结果46例血清HCMV-DNA PCR阳性和(或)血清HCMV-IgM阳性的ITP骨髓巨核祖细胞HCMV晚期抗原基因mRNA阳性19例,GCV治疗有效16例,mRNA阴性27例,GCV治疗有效4例。阳性组疗效高于阴性组,有显著性差异(P<0.01)。结论HCMV感染的ITP患儿,若对常规治疗无效,应检测其巨核祖细胞内HCMV晚期抗原基因mRNA,阳性者是应用更昔洛韦的有效指征。 相似文献
365.
Vascular endothelial growth factor expressing mesenchymal stem cells improves cardiac function in chronic myocardial infarction in pigs 总被引:5,自引:1,他引:5
Yi F Guo WY Lü AL Wang HC Li H Li WJ Liu B Zhang DX Luan RH Cheng HX Li F Qin T Zhao ZJ Gao F Jia GL 《中华医学杂志(英文版)》2006,119(19):1664-1668
Transplantation of mesenchymal stem cells (MSCs) for myocardial reconstruction has shown promise in both animal models and human phase 1 clinical studies. Vascular endothelial growth factor (VEGF) is a strong therapeutic agent for treating ischaemia by inducing angiogenesis. The feasibility of ex vivo MSCs mediated gene transfer is documented. Matsumoto and colleagues have recently reported genetically engineered MSCs carrying VEGF165 delivery for revascularization in a model of acute myocardial infarction (MI). The promising data from our laboratory in both angiogenesis and MSCs transplantation in cunicular heart model of acute MI have prompted us to attempt the combined and simultaneous application of the two strategies. 相似文献
366.
CUI Jian-wei HU Yi-yang FANG Zhi-hong WANG Xiao-ning CHENG Yang PENG Jing-hua FENG Qin ZHANG Hui 《中国结合医学杂志》2006,12(4)
Objective: To study the intervention effects of Jianpi Liqi Huoxue Decoction ( 健脾理气活血汤, JLHD) on lipid peroxidative liver injury induced by alcohol. Methods: The rat alcoholic model of liver disease (ALD) induced by Lieber-DeCarli liquid diet was established. Thirty-two male SD rats were randomly divided into 4 groups: the normal group ( n = 5), the control group ( n = 9), the model group ( n = 9) and the JLHD group (n = 9). From the 4th week after modeling, the rats were given JLHD or distilled water by gastrogavage respectively, and the samples of blood and liver tissues were taken out from the rats for determination by the end of the 8th week. The hepatic pathological changes were observed with HE staining; the liver injury related indices, including activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum, γ-glutamyl transpeptidase (γ-GT) activity and triglyceride (TG) content in liver tissues, as well as the lipid peroxidation related indices, including malonaldehyde (MDA) content and nitric oxide synthase (NOS) activity in liver tissue, serum Fe2 level, and the anti-peroxidation capacity related indices, including superoxide dismutase (SOD) activity, glutathion ( GSH) content and reactive oxygen species (antiROS) activity in liver tissues were determined. Results: ( 1 ) There were obvious figures of fatty degeneration and inflammatory infiltration in liver tissues of the model group. As compared with the control group, in the model group, the activity of ALT and AST, and Fe2 content in serum, γ-GT and NOS activity, TG and MDA content in liver tissues were significantly higher ( P<0.01 ), while the activity of SOD, GSH and anti-ROS in liver tissues were significantly lower ( P<0.01 ). (2) The fatty degeneration and inflammatory infiltration of liver tissues in the JLHD group were significantly lessen as compared with those in the model group; and the abnormalities of all the indexes revealed in the model rats were restored to certain extent in the JLHD group,and especially significant were the levels of ALT activity, MDA content and Fe2 , which were nearly normal.Conclusion: JLHD has significant effects against alcoholic liver injury, the acting mechanism of which is likely to be related with its anti-lipid peroxidative effect. 相似文献
367.
Zhao P Cao J Zhao LJ Qin ZL Ke JS Pan W Ren H Yu JG Qi ZT 《第二军医大学学报》2006,27(5):506-506
The nucleocapsid (N) protein of SARS-coronavirus (SARS-CoV) is the key protein for the formation of the helical nucleocapsid during virion assembly. This protein is believed to be more conserved than other proteins of the virus, such as spike and membrane glycoprotein. In this study, the N protein of SARS-CoV was expressed in Escherichia coli DHSalpha and identified with pooled sera from patients in the convalescence phase of SARS. A plasmid pCI-N, encoding the full-length N gene of SARS-CoV, was constructed. Expression of the N protein was observed in COS1 cells following transfection with pCI-N. The immune responses induced by intramuscular immunization with pCI-N were evaluated in a murine model. Serum anti-N immunoglobutins and splenocytes proliferative responses against N protein were observed in immunized BALB/c mice. The major immunoglobulin G subclass recognizing N protein was immunoglobulin G2a, and stimulated splenocytes secreted high levels of gamma interferon and IL-2 in response to N protein. More importantly, the immunized mice produced strong delayed-type hypersensitivity (DTH) and CD^8+ CTL responses to N protein. 相似文献
368.
目的探讨二氧化硫(SO2)对肝、肺微粒体细胞色素P450两种亚型CYP2B1和CYP2E1mRNA表达及活性的影响。方法采用SO2动式染毒技术使雄性Wistar大鼠染毒7天,每天6h,SO2的染毒剂量分别为14、28和56mg/m3。采用分光光度法测定大鼠肝、肺微粒体CYP2E1活性,采用荧光分光光度法测定肝、肺微粒体CYP2B1活性,采用RT-PCR方法测定各组大鼠肝、肺组织中CYP2B1和CYP2E1mRNA表达水平。结果在肝中,较高剂量的SO2(28和56mg/m3)可使CYP2B1活性及mRNA水平降低,肝微粒体CYP2E1活性及mRNA在各剂量组均未发生显著改变。肺组织中CYP2B1活性在56mg/m3剂量组显著降低,但其mRNA水平在28及56mg/m3剂量组均显著降低;肺微粒体CYP2E1活性及mRNA水平在28及56mg/m3SO2处理组均降低显著。结论SO2可降低大鼠肝中CYP2B1和2E1及肺中CYP2B1和CYP2E1的活性及mRNA水平。 相似文献
369.
含氯复方消毒剂杀灭微生物效果的试验观察 总被引:1,自引:0,他引:1
目的:了解含氯复方消毒剂杀菌效果、稳定性及腐蚀性。方法:应用载体定量杀菌试验与金属腐蚀性试验。结果:以含有效氯2000mg/L的该消毒剂对布片上枯草杆菌黑色变种芽孢作用20min,含有效30mg/L的该溶液对布片上金黄色葡萄球菌和大肠杆菌作用10min和3min,含有效氯20mg/L的该溶液对白色念珠菌作用10min,杀灭率均为100%。含有效氯1500mg/L的该消毒剂溶液对不锈钢片上乙型肝炎表面抗原作用30min,可将其抗原性破坏。含有效氯2000ml/L的消毒剂溶液对不锈钢无腐蚀,对铝、铜有轻度腐蚀,对碳钢有中度腐蚀。结论:含氯复方消毒剂具有高效杀菌作用,对金属有腐蚀性。 相似文献
370.
无创正压通气治疗的护理 总被引:5,自引:0,他引:5
通过17例呼吸衰竭患者应用无创正压通气(NIPPV)的临床观察与护理,结合治疗前后血气参数值的对比分析,总结出以下护理体会:心理护理,选择合适的体位及鼻(面)罩是应用NIPPV的前提;防止漏气和面部皮肤压迫性损伤,保持呼吸道通畅,密切观察患者通气效果及呼吸机性能是应用NIPPV的护理重点;密切观察患者病情变化,进行氧疗,协助患者排痰是NIPPV治疗后的护理措施。 相似文献