全文获取类型
收费全文 | 14076篇 |
免费 | 1000篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 193篇 |
儿科学 | 428篇 |
妇产科学 | 260篇 |
基础医学 | 2001篇 |
口腔科学 | 1272篇 |
临床医学 | 1172篇 |
内科学 | 3046篇 |
皮肤病学 | 397篇 |
神经病学 | 908篇 |
特种医学 | 532篇 |
外国民族医学 | 1篇 |
外科学 | 1664篇 |
综合类 | 105篇 |
一般理论 | 6篇 |
预防医学 | 1379篇 |
眼科学 | 242篇 |
药学 | 914篇 |
中国医学 | 84篇 |
肿瘤学 | 548篇 |
出版年
2023年 | 124篇 |
2022年 | 297篇 |
2021年 | 464篇 |
2020年 | 330篇 |
2019年 | 437篇 |
2018年 | 524篇 |
2017年 | 388篇 |
2016年 | 421篇 |
2015年 | 455篇 |
2014年 | 628篇 |
2013年 | 781篇 |
2012年 | 1012篇 |
2011年 | 1058篇 |
2010年 | 664篇 |
2009年 | 559篇 |
2008年 | 713篇 |
2007年 | 788篇 |
2006年 | 634篇 |
2005年 | 594篇 |
2004年 | 491篇 |
2003年 | 398篇 |
2002年 | 385篇 |
2001年 | 294篇 |
2000年 | 287篇 |
1999年 | 231篇 |
1998年 | 177篇 |
1997年 | 149篇 |
1996年 | 157篇 |
1995年 | 117篇 |
1994年 | 122篇 |
1993年 | 77篇 |
1992年 | 102篇 |
1991年 | 106篇 |
1990年 | 102篇 |
1989年 | 91篇 |
1988年 | 92篇 |
1987年 | 101篇 |
1986年 | 86篇 |
1985年 | 78篇 |
1984年 | 69篇 |
1983年 | 52篇 |
1982年 | 56篇 |
1981年 | 33篇 |
1980年 | 37篇 |
1979年 | 38篇 |
1978年 | 34篇 |
1977年 | 28篇 |
1976年 | 30篇 |
1967年 | 25篇 |
1966年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
F G Araujo P M Coelho L H Pereira J Pellegrino 《Clinical and experimental immunology》1977,28(2):289-291
Skin-graft rejection in mice experimentally infected with Schistosoma mansoni is delayed when grafting is performed 60 days after the infection. In mice infected 30 days prior to the grafting, the grafts were rejected at the same time both in infected and in control animals. This observation indicates that impairment of cell-mediated immune response occurs in mice with mature S. mansoni infections. 相似文献
54.
Isabel M. Coelho Maria Teresa Pereira G. Virella R. A. Thompson 《Clinical and experimental immunology》1974,17(4):685-689
The saliva of an individual with selective IgA deficiency was found to contain IgG and IgM, with some of the IgM linked to secretory component. Some specimens showed evidence of low molecular weight immunoglobulin fragments, presumed to be the result of proteolysis. 相似文献
55.
56.
Characterization of Paracoccidioides brasiliensis isolates by random amplified polymorphic DNA analysis. 下载免费PDF全文
C M Soares E E Madlun S P da Silva M Pereira M S Felipe 《Journal of clinical microbiology》1995,33(2):505-507
We initially used 25 different random primers in order to test their ability to generate random amplified polymorphic DNA fragments from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis. From the tested primers we chose five to distinguish between seven isolates of this microorganism. The DNA amplification patterns allowed clear differentiation of the seven isolates into two distinct groups with only 35% genomic identity. One of these groups contained two subgroups with 81% genetic similarity. The random amplified polymorphic DNA analysis method proved to be a good tool for analyzing and comparing different genomes of P. brasiliensis isolates. 相似文献
57.
Cytomegalovirus-infected cell polypeptides immune-precipitated by sera from children with congenital and perinatal infections. 总被引:5,自引:0,他引:5 下载免费PDF全文
Congenital or perinatally acquired human cytomegalovirus (CMV) infections in children may be symptomatic or asymptomatic. In this study, we characterized the electrophoretic properties of CMV-infected cell polypeptides immune-precipitated by sera from children with different types of CMV infections from birth to 4 years of age. Sodium dodecyl sulfate-polyacrylamide gel analysis of immune precipitates formed with radiolabeled extracts of cells infected with CMV strain AD169 showed the following. (i) Electrophoretic profiles of CMV polypeptides immune-precipitated by sera from children with perinatal and congenital infections were similar. At least 11 polypeptides with apparent molecular weights of 150,000, 140,000, 110,000, 100,000, 74,000, 66,000, 50,000, 49,000, 34,000, 25,000, and 20,000 were precipitated. Antibody titer in anticomplement immunofluorescence tests and virus titer in urine correlated with the intensity of polypeptide profiles in autoradiograms. (ii) The initial immune response of children with symptomatic congenital infections was delayed as compared to that of children with asymptomatic congenital and perinatal CMV infections. Sera obtained serially from symptomatic children for years after birth continued to precipitate CMV polypeptides, whereas sera from children with subclinical congenital infections precipitated lesser amounts over time. (iii) Immune precipitates obtained with sera from CMV-infected patients and with monoclonal antibodies to CMV contained polypeptides with comparable electrophoretic and immunological properties. 相似文献
58.
Monoclonal antibodies to human cytomegalovirus: three surface membrane proteins with unique immunological and electrophoretic properties specify cross-reactive determinants 总被引:30,自引:2,他引:30 下载免费PDF全文
Seventy-seven clones of hybridomas selected for reactivity by immunofluorescence with human cytomegalovirus (CMV)-infected cells were produced by fusing mouse myeloma cells with the spleen cells of mice immunized with CMV strain AD169. The clones were classified into seven groups on the basis of the electrophoretic properties of the polypeptides immune precipitated from extracts of CMV-infected cells. Studies on the three groups of monoclonal antibodies directed against CMV surface membrane antigens showed the following. Clones in each group were differentiated by immunoglobulin subclass, neutralizing activity, and reactivity with the antigenic domains of proteins exposed on the surface membranes of intact CMV-infected cells. Monoclonal antibodies in each group precipitated one slowly migrating protein and multiple faster migrating forms which shared antigenic determinants. The first group of monoclonal antibodies precipitated four glycosylated polypeptides with apparent molecular weights of 130,000, 110,000, 100,000, and 60,000. Monoclonal antibody CH51 of this group neutralized infectious virus but failed to react with antigenic domains on the surfaces of infected cells. The second group of monoclonal antibodies precipitated four polypeptides with apparent molecular weights of approximately 66,000, 55,000, 50,000, and 46,000. Monoclonal antibodies CH65 and CH134 in this group had neutralizing activity and reacted with antigenic domains of proteins exposed on the surface of CMV-infected cells. The third group of monoclonal antibodies precipitated four polypeptides with apparent molecular weights of 49,000, 48,000, 34,000, and 25,000. Serological analysis of 15 naturally occurring CMV strains with a panel of monoclonal antibodies to surface membrane proteins showed that the antigenic determinants reactive with the antibodies tested were conserved in all of the strains. Monoclonal antibodies to surface membrane proteins on CMV-infected cells may prove to be valuable reagents for identification of virus isolates. 相似文献
59.
60.
Induction of HLA-DR expression on thyroid follicular cells by cytomegalovirus infection in vitro. Evidence for a dual mechanism of induction. 总被引:1,自引:1,他引:1 下载免费PDF全文
Cytomegalovirus (CMV) infection of primary cultures established from human thyroid nodular and normal (paranodular) tissues resulted in induction of human leukocyte antigen (HLA) DR expression on thyroid follicular cells (TFC), as detected by cell-surface immunofluorescence staining with monoclonal antibodies (MAb). Two distinct modalities of induction were observed. The first type occurred in cultures of normal tissue obtained from CMV-seropositive but not seronegative donors, was detected on 30% to 50% of the TFCs, even though the vast majority of these cells failed to show any morphologic or antigenic evidence of individual CMV infection, and was associated with production of gamma-interferon (gamma-IFN) in vitro. The induced molecules displayed the characteristic DR polypeptide profile on immunoprecipitation and electrophoretic analysis. These results demonstrate that CMV infection of normal thyroid cultures may induce DR expression on TFCs in the absence of pre-existing lymphoid infiltrates and suggest that the induction is the result of an in vitro response to CMV by previously sensitized immunocompetent cells present in these primary cultures. Such a response, associated with the release of gamma-IFN, would induce DR expression on neighboring uninfected cells. The second mode of induction occurred in all CMV-infected cultures, regardless of their tissue origin (nodular or normal) or the serologic status of the donors. Up to 50% of infected TFCs at a late stage of infection, having fully developed CMV antigen-positive intranuclear inclusions, also displayed the cell-surface DR-related determinant recognized by one of the four anti-DR MAbs used. This induction was restricted to TFCs, while CMV-infected fibroblastoid cells present in the monolayers were invariably negative. Induction by CMV of major histocompatibility class II antigens on human epithelial cells may have significant implications in the development of normal immune responses against local viral infection, the enhancement of alloimmune rejection of grafted organs, and the generation of organ-specific autoimmune responses. 相似文献