全文获取类型
收费全文 | 48620篇 |
免费 | 3684篇 |
国内免费 | 1512篇 |
专业分类
耳鼻咽喉 | 206篇 |
儿科学 | 1352篇 |
妇产科学 | 577篇 |
基础医学 | 10721篇 |
口腔科学 | 602篇 |
临床医学 | 4725篇 |
内科学 | 6796篇 |
皮肤病学 | 868篇 |
神经病学 | 2196篇 |
特种医学 | 925篇 |
外国民族医学 | 7篇 |
外科学 | 3334篇 |
综合类 | 7362篇 |
现状与发展 | 6篇 |
预防医学 | 3405篇 |
眼科学 | 367篇 |
药学 | 5430篇 |
26篇 | |
中国医学 | 1876篇 |
肿瘤学 | 3035篇 |
出版年
2024年 | 76篇 |
2023年 | 500篇 |
2022年 | 1165篇 |
2021年 | 1560篇 |
2020年 | 1320篇 |
2019年 | 1315篇 |
2018年 | 1378篇 |
2017年 | 1518篇 |
2016年 | 1585篇 |
2015年 | 1510篇 |
2014年 | 2500篇 |
2013年 | 3105篇 |
2012年 | 2396篇 |
2011年 | 2782篇 |
2010年 | 2064篇 |
2009年 | 1907篇 |
2008年 | 1964篇 |
2007年 | 2105篇 |
2006年 | 1966篇 |
2005年 | 1837篇 |
2004年 | 1687篇 |
2003年 | 1601篇 |
2002年 | 1361篇 |
2001年 | 1218篇 |
2000年 | 1107篇 |
1999年 | 869篇 |
1998年 | 865篇 |
1997年 | 880篇 |
1996年 | 799篇 |
1995年 | 865篇 |
1994年 | 810篇 |
1993年 | 742篇 |
1992年 | 681篇 |
1991年 | 642篇 |
1990年 | 545篇 |
1989年 | 439篇 |
1988年 | 433篇 |
1987年 | 387篇 |
1986年 | 312篇 |
1985年 | 684篇 |
1984年 | 491篇 |
1983年 | 398篇 |
1982年 | 323篇 |
1981年 | 266篇 |
1980年 | 196篇 |
1979年 | 142篇 |
1978年 | 130篇 |
1977年 | 95篇 |
1976年 | 77篇 |
1975年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
【目的】制备和鉴定 β1受体亚型特异性抗体。【方法】人工合成 β1受体细胞膜外第二环 197 2 2 2位氨基酸序列作为抗原。连接钥孔冒贝血蓝蛋白 (KLH)增加抗原性后免疫兔获得抗血清。通过凝胶双扩散实验和ELISA法鉴定其效价 ;通过免疫荧光法及ELISA法鉴定其特异性 ;通过离体蛙心灌流实验鉴定其药理活性。【结果】该抗血清效价高 (分别为 1∶6 4和 1∶10 6)、特异性强 ,能和心肌 β1受体发生特异性结合 (1∶10 4 ~ 1∶10 5) ,为异丙肾上腺素的非竞争性拮抗剂。 (pD2 ′ =1 6 2 )。【结论】成功制备的 β1受体亚型特异性抗体可能成为进一步研究 β1受体分布、功能和定量的有力工具。 相似文献
52.
目的 :观察天然碱性脂 (Stearylamine,SA)脂质体介导绿色荧光蛋白 /碱性成纤维细胞生长因子(GFP/bFGF)基因于不同时间段豚鼠耳蜗中的表达 ,为进一步研究耳聋的基因治疗提供实验基础。方法 :取豚鼠 1 6只 ,分成 4组 ,每组 4只。其中 3只右耳圆窗内注入SA -GFP/bFGF复合物 ,1只同法注入生理盐水作为对照。分别于术后第 2、7、1 4、2 1天取材。在荧光显微镜下观察GFP的表达 ,用免疫组化法检测bFGF的转导情况。结果 :荧光显微镜下见双侧耳蜗于术后第 2天开始部分细胞发出绿色荧光 ,第 7天达到高峰 ,支持细胞及内外毛细胞均显荧光 ,细胞轮廓清晰 ;第 1 4天开始减弱 ,第 2 1天消失。免疫组化染色显示 ,除血管纹外 ,耳蜗各回Corti器、螺旋韧带、螺旋缘及螺旋神经节细胞均有高浓度的表达产物 ,对照动物呈阴性表达。结论 :SA脂质体介导的GFP/bFGF基因单耳给药双侧耳蜗均有高效表达 ,为进一步研究基因治疗耳聋提供了可能。 相似文献
53.
HCC的早期诊断是其治疗的关键,HCC血清标志物的检测又为其诊断提供了有利的途径,并且操作简单,敏感性高和特异性强。目前常用的血清标志物为AFP、AFP变异体、AFP mRNA、AFU、GGT、DCP、AIF、GPC3等。这些标志物的联合使用有助于HCC的诊断及预后。 相似文献
54.
Characterization of gp 50, a major glycoprotein present in rat brain synaptic membranes, with a monoclonal antibody 总被引:4,自引:0,他引:4
Philip W. Beesley Toni Paladino Claude Gravel Richard A. Hawkes James W. Gurd 《Brain research》1987,408(1-2):65-78
Several cell lines secreting monoclonal antibodies (Mabs) against a major forebrain synaptic membrane (SM) glycoprotein, gp 50, have been raised. Western blots show that the Mabs react with a polypeptide doublet of Mrs 49 and 45 kDa. These polypeptides exist solely in a concanavalin A (Con A) binding form. Removal of the Con A receptors by digestion with endo-beta-N-acetylglucosaminidase H (endo H) lowers the Mrs of the glycoprotein doublet to 36.5 and 34 kDa. Western blots of 2D polyacrylamide gels indicate that gp 50 exists in several isoforms. Solid phase radioimmunoassay (RIA) and Western blots of brain subcellular fractions show the antigenic material to be concentrated in the SM fraction, but to be present in much lower amounts in synaptic junctions and postsynaptic densities. Gp 50 appears to be brain specific. Regional distribution studies show that it is present in all brain regions but is two-fold concentrated in cerebellum, brainstem and midbrain compared to forebrain. Immunocytochemical studies of several brain regions show that gp 50-like immunoreactivity is neuron specific and is concentrated in selected neuronal species, particularly granule cells. In both cerebellar and hippocampal granule cells gp 50-like immunoreactivity is localized in the perikarya and primary dendrites. Though immunocytochemistry did not show staining of synaptic regions this may be due to masking of the reactive epitope. The results are discussed in terms of the molecular properties of gp 50 and its subcellular localization in brain tissue. 相似文献
55.
本文报告用间接免疫荧光法检测特异性IgG抗体对流行性出血热的诊断意义。53例不同病期的出血热患者的血清,其间接荧光抗体的阳性率为49/53(占92.45%)。有77.36%的患者血清,检出IgG抗体的时间是在发病后的1~2周。血清中IgG的滴度与疾病的严重性无密切相关。另25例非EHF患者,其血清特异性IgG抗体均为阴性。可见检测特异性IgG抗体对EHF的诊断颇为有用。 相似文献
56.
Lewis rats were immunized with a homogenate of human spinal cord. Splenocytes from the immunized rats were fused with cells from the SP2/0-Ag14 cell line to form hybrids that were subsequently screened immunohistochemically for secretion of antibodies against myelin. Thirty hybrids secreting anti-myelin antibodies were cloned. One secreted antibody (774) that immunohistochemically stained central nervous system (CNS) myelin but not peripheral nervous system (PNS) myelin also bound to the surface of peripheral blood macrophages. Hence we have identified an epitope that is shared by peripheral blood macrophages and CNS myelin. 相似文献
57.
目的探讨急性脑血管病患者早期肾损害的机制及早期监测指标。方法对194例急性脑血管病患者(包括脑梗死129例,脑出血65例)及60例正常对照者同时测定血半胱氨酸蛋白酶抑制剂C(Cys-C)和血肌酐(SCr)浓度,对其中血Cys-c浓度增高但SCr浓度正常的48例急性脑血管病肾早期损害患者用甘露醇治疗,并检测治疗前后血Cys-c浓度。结果在早期肾损害组,血Cys-c浓度明显高于对照组(P<0.001),而SCr浓度2组无显著性差异(P>0.05)。48例急性脑血管病肾早期损害者经甘露醇治疗后,血Cys-c浓度较治疗前明显降低(P<0.001)。结论血清Cys-c测定有助于早期发现肾功能损害,治疗脑血管病的同时应注意监测肾功能。 相似文献
58.
Local mucosal immunoglobulin E production: does allergy exist in non‐allergic rhinitis? 总被引:2,自引:0,他引:2
In this review, we critically evaluate the evidence for local IgE production in allergic rhinitis mucosa and the concept of local allergy in non-atopic idiopathic rhinitis. Significantly, fewer studies have focused on the disease pathways associated with non-allergic rhinitis compared with their allergic counterparts. Recently, there's been a revival of the hypothesis concerning the existence of local tissue-specific allergic disease confined to the nasal mucosa of some systemically non-atopic rhinitis subjects. Providing the evidence for local mucosal IgE production in allergic rhinitis is a pre-requisite to reviewing its existence in non-allergic rhinitis. In addition, practical and theoretical approaches useful in the detection of allergy in non-allergic rhinitis will be discussed. Furthermore, successful therapeutic regimens used in the treatment of non-allergic rhinitis will be examined as these could provide an insight into the underlying pathophysiology of this common but poorly understood disease. 相似文献
59.
可溶性细胞间黏附分子-1在急性肝内胆汁淤积兔模型中的表达 总被引:1,自引:1,他引:0
目的探讨可溶性细胞间黏附分子(sICAM-1)在急性肝内胆汁淤积兔模型中的表达及其意义。方法39只健康的新生大耳白兔随机分成4组:3个实验组(n=9)和1个空白对照组(n=12)。每个实验组分别为3个时间点处理组(24、48、72 h)。实验组采用1次灌服α-荼异硫氰酸盐(ANIT)200 mg/kg方法造成急性肝内胆汁淤积。按时分批取标本,检测其血清和胆汁中sICAM-1水平。结果实验组血清、胆汁中sICAM-1各时间点水平明显高于正常对照组(P均<0.05),其中48 h>72 h>24 h。结论sICAM-1在胆汁淤积中表达升高,与肝脏损伤程度和病程相关。 相似文献
60.
Michael Kendler Wolfgang Uter reas Rueffer Raffael Shimshoni Eckehardt Jecht 《Pediatric allergy and immunology》2006,17(2):141-147
Atopic eczema/dermatitis syndrome (AEDS) commonly often arises during early infancy. In several intervention studies a beneficial influence on AEDS course of certain intestinal bacteria, administered as 'probiotics', has been described. To evaluate the possible role of the natural intestinal microflora in children with allergic eczema/dermatitis syndrome regarding immediate type hypersensitivity to food allergens, children with food allergy (AAEDS, n = 68) have been compared with children without detectable food allergy (NAEDS, n = 25). All children (n = 93) in preschool age, mean age of 2.6 (+/-1.8) years, diagnosed with AEDS who were treated as inpatients in 2003 in a dermatological hospital were included. The correlation between fecal microflora, parasites and specific immunoglobulin E (IgE) antibodies against common food allergens was analyzed. A similar composition of intestinal microflora in children with AAEDS and NAAEDS was found. The food allergens that were most frequently detected were egg white, cow milk, casein, peanut and hazelnut. Furthermore, a significant association between IgE sensitization against important food allergens and components of the fecal microflora could not be demonstrated. With aging changes occur in the intestinal microbiota [Proteus/Klebsiella and age (rho = -0.607) and Enterococcus and age (rho = -0.428)]. In two subjects of the AAEDS group Blastocystis hominis was found. The composition of natural intestinal microflora in children with AAEDS and NAAEDS was similar. Hence, there is no evidence of a role of the intestinal microflora with regard to the development of infant (food) allergy in children with AEDS. The possible consequences for allergic diseases later in life require further investigation. 相似文献