首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4703篇
  免费   295篇
  国内免费   72篇
耳鼻咽喉   15篇
儿科学   80篇
妇产科学   26篇
基础医学   1050篇
口腔科学   34篇
临床医学   383篇
内科学   738篇
皮肤病学   63篇
神经病学   206篇
特种医学   55篇
外科学   242篇
综合类   459篇
现状与发展   1篇
预防医学   1122篇
眼科学   36篇
药学   359篇
中国医学   31篇
肿瘤学   170篇
  2024年   2篇
  2023年   40篇
  2022年   113篇
  2021年   178篇
  2020年   137篇
  2019年   116篇
  2018年   112篇
  2017年   136篇
  2016年   149篇
  2015年   156篇
  2014年   257篇
  2013年   336篇
  2012年   291篇
  2011年   281篇
  2010年   217篇
  2009年   229篇
  2008年   209篇
  2007年   223篇
  2006年   214篇
  2005年   199篇
  2004年   156篇
  2003年   152篇
  2002年   102篇
  2001年   101篇
  2000年   109篇
  1999年   95篇
  1998年   94篇
  1997年   76篇
  1996年   53篇
  1995年   69篇
  1994年   71篇
  1993年   51篇
  1992年   53篇
  1991年   44篇
  1990年   44篇
  1989年   39篇
  1988年   28篇
  1987年   28篇
  1986年   18篇
  1985年   11篇
  1984年   15篇
  1983年   10篇
  1982年   12篇
  1981年   10篇
  1980年   9篇
  1979年   6篇
  1978年   4篇
  1977年   6篇
  1973年   2篇
  1968年   2篇
排序方式: 共有5070条查询结果,搜索用时 359 毫秒
51.
目的:建立检测血清中人类疱疹病毒6型(HHV-6)抗体的间接免疫荧光方法(IFA),检测人群中HHV-6抗体的水平。方法:用HHV-6GS株感染脐血单个核细胞制备抗原片,建立检测血清中HHV-6抗体的IFA法,并对长春市人群血清中的HHV-6抗体水平进行检测。结果:成功地建立了检测XHV-6抗体的间接免疫荧光方法,对长春市人群血清中的XHV-6抗体水平进行检测表明,XHV-6抗体阳性率为65.2%。结论:建立了特异性的IFA法,用于HHV-6感染的调查。  相似文献   
52.
The IgG subclasses of immunoglobulin for intravenous injection (IVIg) were investigated after various different types of treatment. The level of IgG2 was relatively low in preparations treated with pepsin, but by changing the clone producing anti-IgG2 antibody, the level approached that of normal human serum. Though undetectable in sulfonated immunoglobulin preparations, IgG3 was detected after reoxidation. When determining the IgG subclasses of IVIg, it must be kept in mind that the apparent value may subsequently become lower due to the depressed reaction of the antibody.  相似文献   
53.
54.
流感病毒血凝素基因工程抗体的抗病毒实验效果观察   总被引:1,自引:0,他引:1  
目的:对昆虫细胞系统表达纯化的中和性流感病毒血凝素基因工程全抗体IgG-IV-2,IgG-IV-6进行体外和体内抗病毒效果的研究。方法:对比抗体应用前后病毒在MDCK细胞中的病毒滴度和动物模型中粘膜用药前后鼠肺内病毒滴度的改变,验证抗体的粘膜抗感染效果。结果:两株基因工程抗体使4.5log10TCID50滴度的病毒下降1/2的剂量分别为0.8μg和0.5μg;动物模型的粘膜给药表明使4.0log10TCID50的病毒下降1/2所需的抗体剂量IgG-IV-2为0.25mg/kg体重,IgG-IV-6为0.1mg/kg体重,联合应用时为0.08mg/kg体重。结论:获得的基因工程抗体具有体内体外的抗病毒效果,能够中和病毒毒力。  相似文献   
55.
Creation of a model for multiple sclerosis in Callithrix jacchus marmosets   总被引:7,自引:0,他引:7  
 Multiple sclerosis (MS) is an inflammatory disease of the CNS white matter characterized pathologically by the accumulation of perivascular and parenchymal T lymphocytes (T cells), and macrophage infiltration associated with myelin destruction. MS lesions are also characterized by the death of oligodendrocytes (the myelin-producing cells) and proliferation and hypertrophy of astrocytes with scar tissue (gliosis) replacing normal myelin. These changes result in the loss of axonal conduction for neurons of the CNS and in clinical disability. MS is thought to be an autoimmune disease, in particular because of its analogy with the disease model of experimental allergic encephalomyelitis (EAE). Despite extensive research and the availability of various EAE models in laboratory rodents the etiology of human MS has not been identified, and to date no effective treatment exists. Phylogenetic differences may limit the usefulness of existing EAE models, and indeed no single form of rodent EAE recapitulates all the clinical and pathological features of MS. Here we describe a novel form of EAE created in a nonhuman primate, the common marmoset Callithrix jacchus. Active immunization of these monkeys with whole myelin produces a primary demyelinating disease with a chronic relapsing-remitting course, characterized pathologically by moderate inflammation with prominent and early demyelination and gliosis reminiscent of human MS. Adoptive and passive transfer experiments have permitted definition of the mechanisms responsible for the MS-like pathology. Production of the fully demyelinated lesion requires synergism between encephalitogenic (e.g., disease-inducing) T cells and pathogenic antibody. The antigens of myelin that promote encephalitogenic T cell and antibody responses in this system have been identified. Because of the similarity between the two conditions and the high degree of conservation in immune and nervous system genes between nonhuman primates and humans, future studies of marmoset EAE will likely accelerate the development of therapies for human MS. Received: 6 June 1996 / Accepted: 17 December 1996  相似文献   
56.
This investigation uses a system for inducing and detecting anti-tetanus toxoid antibody (anti-TT) synthesis to study specific antibody (Ab) synthesis by bone marrow mononuclear cells (MC). We measured the amounts of anti-TT secreted and the number of B cells secreting antibody (Ab). The ELISA plaque detects single B cells secreting specific Ab. The results show that (1) spontaneous anti-TT secretion by MC is higher than spontaneous anti-TT secretion by peripheral blood lymphocytes (PBL) using an ELISA plaque (P<0.01); (2) spontaneous anti-TT production by MC correlated with the serum anti-TT titers as measured by an ELISA (r=0.75,P=0.005); (3) two types of marrow B cells were identified—one that spontaneously secretes anti-TT and another that produces anti-TT after TT-stimulation; (4) the frequency of anti-TT-secreting B cells is higher in MC than in PBL; (5) the amount of Ab secreted per marrow B cell is not different from that secreted by a peripheral B cell; and (6) marrow B cells could be induced to produce anti-TTin vitro up to 10 months without added cytokines. These results show that bone marrow is a major repository for differentiated B cells that spontaneously produce Abs to maintain circulating Abs titers and for memory B cells that can be induced to produce specific Ab.  相似文献   
57.
目的构建人免疫缺陷病毒1型(HIV-1)特异性噬菌体抗体库,制备人源抗HIV-1gp120单克隆抗体。方法以半巢式聚合酶链反应(PCR)从HIV-1感染者外周血单个核淋巴细胞中扩增抗体重链Fd和轻链(k)基因,与噬菌体载体pComb3连接,构建噬菌体抗体Fab组合文库。对抗体库进行3轮吸附-洗脱-扩增的亲和选择后,以ELISA法筛选抗HIV-1gp120噬菌体抗体,并进行DNA序列分析和Fab的可溶性表达。结果半巢式PCR有效地扩增出Fd和k基因,以此构建成容量为195×107的噬菌体抗体库。3轮亲和选择使特异性抗体得到高度富集,抗HIV-1gp120噬菌体抗体阳性克隆占32%。对一阳性克隆抗体基因CH1和CL部分DNA序列进行了测定,并在大肠杆菌表达出可溶性Fab。结论抗HIV-1特异性噬菌体抗体库的构建和人源抗HIV-1gp120单克隆抗体的制备为今后筛选抗HIV中和抗体奠定了基础,具有重要的应用价值。  相似文献   
58.
Varicella-zoster virus (VZV) DNA was detectable by in-situ hybridization in blood mononuclear cells (MNCs) of patients with varicella or zoster for 2–56 days after the onset of a rash. VZV DNA was present in many MNCs from one acute varicella patient 2 days after the onset of the rash and was rarely found in MNCs during acute zoster, convalescent zoster, and convalescent varicella. The morphology of MNCs containing VZV was heterogenous, although most viral-DNA-containing MNCs were large monocytoid cells. Serial examination of blood MNCs from one adult with varicella revealed VZV DNA up until 8 weeks, but not 16 weeks, after the appearance of the rash; parallel studies in four zoster patients showed VZV DNA up until 3 weeks, but not later than 7 weeks after the appearance of the rash. These results indicate that MNCs become infected with VZV during the primary encounter with VZV (varicella) and during reactivation (zoster) and that infection continues for weeks after the onset of the skin rash. Furthermore, the detection of VZV DNA in blood MNCs of uncomplicated zoster patients coincides with the period during which these patients experience pain.  相似文献   
59.
Antigen-specific vaccines are one of several molecularly targeted approaches under investigation as possible treatments for prostate cancer. Important to the development of vaccines is the identification of appropriate target antigens. We hypothesized that antigens of the prostate might be identified in patients with the chronic prostatitis/pelvic pain syndrome, a syndrome for which an autoimmune pathology has been proposed. Such antigens might represent naturally recognized target antigens of the prostate that could be investigated in the future as prostate tumor antigens. In this report, we used SEREX to identify proteins expressed in a prostate cDNA expression library recognized by IgG from the sera of patients with chronic prostatitis. Candidate proteins were evaluated using a panel of sera from 62 subjects with symptomatic prostatitis and 71 control male blood donors. We identified one protein that was recognized primarily in sera from subjects with prostatitis compared with controls. MAD-PRO-34, a nucleolar autoantigen, was recognized in 6/62 subjects and 0/71 controls (p = 0.00897). This protein had previously been identified as an autoantigen in patients with prostate cancer. In addition, the NY-CO-7 protein was recognized in 9/62 subjects and 3/71 controls (p = 0.0654). Two subjects had IgG specific for both the MAD-PRO-34 and NY-CO-7 gene products. Our results demonstrate that some patients with the chronic prostatitis/pelvic pain syndrome have autoantibodies to specific proteins. Proteins identified, and MAD-PRO-34 in particular, could be further investigated as potential prostate tumor antigens.  相似文献   
60.
Inhibiting complement anaphlytoxin C5a during sepsis may prevent sepsis mortality. Although human anti-C5 antibodies exist, their therapeutic use in microbial sepsis has been avoided because of the hypothesis that inhibiting C5b will prevent formation of the bactericidal membrane attack complex (MAC) and worsen clinical outcome. We wished to test the hypothesis that inhibition of C5 would improve outcomes in sepsis. Sepsis was induced in rats by laparotomy and cecal ligation and puncture (CLP) by an IACUC-approved protocol. Sham animals underwent laparotomy without CLP. Following CLP rats were randomized to receive a single IV dose of purified IgG ant-C5 antibody (Ab) or control IgG Ab. Anti-C5 Ab treated rats (n = 20) had significantly lower mortality vs. controls (n = 21), 20% vs. 52% (P = 0.019, log-rank). Analysis of bacterial load by culture of spleen and liver homogenates showed a reduction in colony forming units in anti-C5 Ab treated rats vs. control IgG (P = 0.003 and 0.009, respectively). Anti-C5 treatment reduced lung injury as measured by total MPO content of lung tissue (P = 0.024). Finally, rats genetically deficient in C6 production, unable to form MAC but capable of producing C5a and C5b, were protected from CLP-induced sepsis mortality. Our results show that in anti-C5 antibody therapy prevents CLP sepsis-induced mortality and improves lung injury. Inhibition of the complement MAC does not increase bacterial load or mortality, therefore, the use of anti-C5 therapy may be beneficial rather than detrimental in sepsis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号