全文获取类型
收费全文 | 170551篇 |
免费 | 16113篇 |
国内免费 | 10032篇 |
专业分类
耳鼻咽喉 | 1360篇 |
儿科学 | 2611篇 |
妇产科学 | 990篇 |
基础医学 | 11127篇 |
口腔科学 | 3199篇 |
临床医学 | 20752篇 |
内科学 | 15901篇 |
皮肤病学 | 1852篇 |
神经病学 | 4108篇 |
特种医学 | 6001篇 |
外国民族医学 | 18篇 |
外科学 | 15315篇 |
综合类 | 45789篇 |
现状与发展 | 41篇 |
一般理论 | 1篇 |
预防医学 | 19841篇 |
眼科学 | 2411篇 |
药学 | 20753篇 |
211篇 | |
中国医学 | 15796篇 |
肿瘤学 | 8619篇 |
出版年
2024年 | 797篇 |
2023年 | 2139篇 |
2022年 | 5492篇 |
2021年 | 6724篇 |
2020年 | 5895篇 |
2019年 | 3503篇 |
2018年 | 3606篇 |
2017年 | 4730篇 |
2016年 | 3728篇 |
2015年 | 6591篇 |
2014年 | 8837篇 |
2013年 | 10335篇 |
2012年 | 14840篇 |
2011年 | 15718篇 |
2010年 | 14064篇 |
2009年 | 12561篇 |
2008年 | 13048篇 |
2007年 | 12762篇 |
2006年 | 11643篇 |
2005年 | 9237篇 |
2004年 | 6999篇 |
2003年 | 5931篇 |
2002年 | 4679篇 |
2001年 | 4302篇 |
2000年 | 3210篇 |
1999年 | 1461篇 |
1998年 | 585篇 |
1997年 | 533篇 |
1996年 | 428篇 |
1995年 | 362篇 |
1994年 | 358篇 |
1993年 | 225篇 |
1992年 | 202篇 |
1991年 | 196篇 |
1990年 | 146篇 |
1989年 | 144篇 |
1988年 | 105篇 |
1987年 | 123篇 |
1986年 | 91篇 |
1985年 | 66篇 |
1984年 | 59篇 |
1983年 | 53篇 |
1982年 | 41篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 15篇 |
1959年 | 15篇 |
1958年 | 19篇 |
1957年 | 14篇 |
1954年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
101.
102.
Rosiglitazone, an agonist of peroxisome proliferator-activated receptor γ, reduces pulmonary inflammatory response in a rat model of endotoxemia 总被引:3,自引:0,他引:3
Objective: The effect of rosiglitazone, a potent peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, on pulmonary inflammation
in endotoxemia was investigated.
Materials and methods: Male Wistar rats were given either lipopolysaccharide (LPS, 6 mg/kg i.v.) or saline, pretreated with rosiglitazone (0.3 mg/kg
i.v.) or its vehicle (dimethyl sulphoxide) 30 min before LPS. The selective PPAR-γ antagonist GW9662 (0.3 mg/kg i.v.) was
given 20 min before rosiglitazone. Wet/dry weight (W/D) ratio, myeloperoxidase (MPO) activity, malondialdehyde (MDA) as well
as TNF-α and CINC-1 concentrations were measured in lung tissues 4 h after LPS injection. Expression of ICAM-1, NF-κB p65
and PPAR-γ were also determined by immunohistochemistry or Western blot analysis.
Results: Rosiglitazone pretreatment significantly attenuated the increases in W/D ratio, MPO activity and MDA levels, and reduced
pulmonary overproduction of TNF-α and CINC-1 as well as expression of ICAM-1 following endotoxemia. Rosiglitazone also inhibited
the nuclear localization of NF-κB and up-regulated the expression of PPAR-γ protein. The specific PPAR-γ antagonist GW9662
abolished the effect of rosiglitazone.
Conclusion: These findings suggest that PPAR-γ agonists might be used as therapeutic agents in the therapy of inflammatory lung injury
related to endotoxemia.
Received 8 January 2005; returned for revision 6 July 2005; returned for final revision 20 July 2005; accepted by M. Katori
31 July 2005 相似文献
103.
Fas蛋白在糖尿病大鼠局灶性脑缺血再灌注损伤后海马区的表达及意义 总被引:3,自引:0,他引:3
目的探讨Fas蛋白在糖尿病大鼠脑缺血再灌注海马区神经元损伤中的表达及意义。方法健康雄性Wister大鼠60只,随机分为4组:①正常对照组,②假手术组,③脑缺血再灌注组(NIR),④糖尿病脑缺血再灌注组(DIR组);采用STZ诱导糖尿病和线栓法建立大脑中动脉闭塞(MCAO)模型,HE法观察海马CA1神经元缺失,用免疫组化方法检测Fas在糖尿病大鼠脑缺血再灌注海马神经元损伤中的表达。结果HE染色:正常对照与假手术组未见神经元缺失和细胞凋亡,DIR组与脑缺血再灌注组均见神经元缺失和神经细胞凋亡,而DIR组比脑缺血再灌注组神经元缺失严重(P<0.05)。正常对照与假手术组极少见Fas免疫染色阳性细胞,DIR组与脑缺血再灌注组明显见Fas免疫染色阳性细胞,且DIR组比脑缺血再灌注组多(P<0.05)。结论Fas介导的细胞凋亡可能是糖尿病脑缺血再灌注损伤后海马区神经元损伤的机制之一。 相似文献
104.
我们对采用PCR和聚丙烯酰胺凝胶电泳鉴别出的37例DNA完全来自父方的遗传学完全性葡萄胎(g-CHM)进行基因组中CTTtriplex系统各基因座位(CSF1PO、TPOX和TH01)等位基因分布的分析,并初步研究了这些等位基因分布与临床预后的关系。结果显示,在37例g-CHM中,CSF1PO座位中3个等位基因(11,12和14)和TPOX座位中的1个等位基因(11)的出现率与它们在北京地区人群中的基因频率差异显著;g-CHM中CSF1PO、TPOX和TH01基因座位杂合度显著低于北京地区人群的杂合度(P值均远小于0.01);在23例良性g-CHM和10例侵袭性g-CHM中:CSF1PO座位的等位基因10、11在良性中的出现率高于在侵袭性g-CHM中(P=0.026148),等位基因12在良性中的出现率低于在侵袭性g-CHM中(P=0.023879);TPOX座位的等位基因8在良性中的出现率高于在侵袭性g-CHM中(P=0.004322),而等位基因11在良性中的出现率低于其在侵袭性g-CHM中(P=0.008671)。上述结果提示,葡萄胎基因组中存在某些等位基因分布与在人群中的分布不同,而且葡萄胎是否具有侵袭性也和某些等位基因的出现率过高或过低有相关性,这些与侵袭性有关的等位基因可能成为预测葡萄胎是否具有侵袭性的标志物。 相似文献
105.
Chen YN Chen SY Zeng LJ Ran JM Xie B Wu MY Wu YZ 《British journal of biomedical science》2003,60(1):9-13
Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure. 相似文献
106.
7832例孕妇HCMV-IgM的检测分析 总被引:1,自引:0,他引:1
吴满武 《中国优生与遗传杂志》2007,15(6):53-53
目的为了解孕妇人巨细胞病毒(HCMV)近期感染状况。方法采用酶联免疫吸附试验(ELISA)对7832例孕妇的静脉血标本进行了HCMV-IgM检测。结果在7832例孕妇中检测出HCMV-IgM阳性标本67例,阳性率为0.86%。结论在孕妇中巨细胞病毒有一定的近期感染率。 相似文献
107.
目的:通过观察与Ⅰ型超敏反应相关的生物活性介质--组织胺对家兔肝脏有无直接损伤作用,进一步论证Ⅰ型超敏反应对肝脏的损伤作用.方法:选择34只家兔随机分为对照组、实验Ⅰ组和实验Ⅱ组3组;对照组只进行正常饲料喂养,实验Ⅰ组在正常饲料喂养的同时每天给予0.4μg/kg耳静脉注射磷酸组胺注射液,实验Ⅱ组在正常饲料喂养的同时每天给予0.08 μg/kg耳静脉注射磷酸组胺注射液;动态观察以上3个组的血清谷丙转氨酶(ALT)及血清谷草转氨酶(AST)变化;利用光学显微镜观察以上3个组肝组织的病理变化.结果:无论是实验Ⅰ组或实验Ⅱ组,经过一段时间的观察,发现血清内ALT和AST含量均显着高于对照组(P<0.01),但Ⅰ、Ⅱ组之间无显着性差异(P>0.05);实验Ⅰ组和实验Ⅱ组在显微镜下观察,其肝脏均有不同程的损伤和病理改变,且实验Ⅱ组的损伤和变化大于实验Ⅰ组,而对照组的肝脏则无明显的病理变化.结论:组织胺对家兔肝脏确实有一定的损伤作用,而且随着投予剂量和时间的增加,肝脏的损伤和病理变化也越显著;通过本研究,可以得出Ⅰ型超敏反应导致肝脏病理变化及损伤的见解. 相似文献
108.
Lattice constants (LCs) of all possible 96 apatite compounds, A(5)(BO(4))(3)C, constituted by A[double bond]Ba(2+), Ca(2+), Cd(2+), Pb(2+), Sr(2+), Mn(2+); B[double bond]As(5+), Cr(5+), P(5+), V(5+); and C[double bond]F(1-), Cl(1-), Br(1-), OH(1-), are predicted from their elemental ionic radii, using pattern recognition (PR) and artificial neural networks (ANN) techniques. In particular, by a PR study it is demonstrated that ionic radii predominantly govern the LCs of apatites. Furthermore, by using ANN techniques, prediction models of LCs a and c are developed, which reproduce well the measured LCs (R(2)=0.98). All the literature reported on 30 pure and 22 mixed apatite compounds are collected and used in the present work. LCs of all possible 66 new apatites (assuming they exist) are estimated by the developed ANN models. These proposed new apatites may be of interest to biomedical research especially in the design of new apatite biomaterials for bone remodeling. Similarly these techniques may also be applied in the study of interface growth behaviors involving other biomaterials. 相似文献
109.
抗SARS-CoV抗原的人源Fab段噬菌体抗体库的构建 总被引:6,自引:1,他引:6
目的 :利用抗SARS冠状病毒IgG抗体阳性的SARS康复患者外周血淋巴细胞 ,构建人源Fab段抗体文库。方法 :制备外周血淋巴细胞总RNA ,逆转录成cDNA。以其为模板 ,利用针对家族特异性Ig基因的引物扩增重链Fd段和轻链基因 ,并重组到噬菌粒载体pComb3中 ,将重组噬菌粒载体电转化大肠杆菌XL 1Blue,酶切鉴定抗体库的重组率 ,并测定噬菌体抗体库的库容量。结果 :构建了源于SARS康复患者血清中抗Fab段的抗体文库 ,轻链、重链Fd段基因的重组率分别为91%和 75 % ,库容量为 7.2 3× 10 7。结论 :成功地构建了抗SARS CoV抗原的人源Fab段噬菌体抗体库 相似文献
110.
Progressive deterioration of beta-cell function is proposed as a disease-related factor of sulphonylurea (SU) failure in type 2 diabetes. If it gradually worsens over time then disease duration may mirror the progressive beta-cell deterioration. The aim of the present study is to assess whether or not disease duration is influential in remodelling the secretion pattern of insulin-like molecules and in glucose control of SU-treated type 2 diabetes. A research model is used to investigate proinsulin secreting capacity over time, using two groups of patients: i) disease duration <5 years (n=62), comprising SU responders (SUr; n=48) and SU failures (SUf; n=14); and ii) disease duration > or = 5 years (n= 37), comprising an SUr group (n=17) and an SUf group (n=20). Blood samples are taken at 0 h, 0.5 h 1 h, 2 h and 3 h during a standard oral glucose tolerance test and measured for glucose, total proinsulin (TPI), intact proinsulin (IPI) and specific insulin (SI) concentrations. Pairwise comparison of estimated marginal means of blood glucose, SI, IPI and TPI levels at each time point are carried out between groups and subgroups. (SUr vs. SUf). Homa insulin resistance index (IR index) is applied to analyse IR between the groups. It was found that patients with shorter disease duration had higher proinsulin (TPI and IPI) levels at all time points (P<0.05), together with a lower glucose level at 2 h and 3 h (P<0.05). Homa insulin index analysis showed no difference between the two groups (P=0.26). Results also showed that the SUr group had a significantly lower glucose level at Oh and 3h (P<0.05), although no significant difference in insulin and proinsulin levels was found between the SUr and SUf groups. In conclusion, proinsulin may play an important role in glucose control in SU-treated type 2 diabetes, but the effect is reduced in SUf patients. 相似文献