首页 | 官方网站   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   847篇
  免费   61篇
  国内免费   1篇
医药卫生   909篇
  2021年   9篇
  2018年   10篇
  2015年   8篇
  2014年   18篇
  2013年   21篇
  2012年   28篇
  2011年   31篇
  2010年   17篇
  2009年   16篇
  2008年   38篇
  2007年   31篇
  2006年   26篇
  2005年   25篇
  2004年   30篇
  2003年   43篇
  2002年   30篇
  2001年   21篇
  2000年   12篇
  1999年   12篇
  1998年   7篇
  1997年   7篇
  1996年   9篇
  1995年   9篇
  1994年   11篇
  1992年   20篇
  1991年   23篇
  1990年   19篇
  1989年   15篇
  1988年   24篇
  1987年   17篇
  1986年   19篇
  1985年   22篇
  1984年   14篇
  1983年   24篇
  1982年   17篇
  1981年   13篇
  1980年   9篇
  1979年   16篇
  1978年   24篇
  1977年   8篇
  1976年   10篇
  1975年   10篇
  1974年   11篇
  1972年   8篇
  1971年   16篇
  1970年   6篇
  1969年   9篇
  1967年   6篇
  1966年   6篇
  1965年   8篇
排序方式: 共有909条查询结果,搜索用时 0 毫秒
1.
We report the outcome of a femoral stem designed for press-fit insertion and cemented with a thin mantle. During the years 1986–1992 we performed 346 primary total hip replacements in 305 patients. Their mean age at the time of the surgery was 75 (range, 52–91 years). During the follow-up, 206 patients had died (227 hips) and 3 were lost. This left us with 96 patients (116 hips), who were followed for a mean of 13 years (range, 11–18 years). Stem survivorship according to Kaplan–Meier analysis indicated a total survival of 0.982 (confidence intervals, 0.952–1). The mechanical survival rate was 0.985 (confidence intervals, 0.955–1) at 17 years with one patient at risk. Fifty-nine (70%) of the surviving patients were very satisfied with the operated hip, 22 (26%) were satisfied, 2 (2.5%) were content, and 1 (1.5%) was dissatisfied. Then, the press-fit stem allowing minimal cement has a 17-year survival rate of 0.98.  相似文献   
2.
3.
4.
Dubbelman and co-workers have determined intraocular spacings and surface shapes in living eyes by means of corrected Scheimpflug images in a large number of subjects of different age at several levels of accommodation. They give relationships for key anterior segment parameters as a function of age and level of accommodation. These are used in this paper to build a schematic eye incorporating aspheric surfaces. This eye model is analysed by means of ray tracing with a technique developed for use with a common spreadsheet computer program. The Dubbelman eye model appears to be well corrected for spherical aberration. Compared with measurements on real eyes it agrees well in general, but spherical aberration is negative, while in real eyes it tends to be positive.  相似文献   
5.
Proportions of T cells and T cell subsets, as identified by their Fc receptors (FcR) for IgM and IgG (Tmu and T gamma), were determined in the peripheral blood lymphocyte (PBL) and cerebrospinal fluid (CSF) lymphocyte populations in patients with multiple sclerosis (MS). On average, MS patients had 79% total T cells (62% of which were T gamma, 66% Tmu) in CSF lymphocytes compared to 66% total T cells (30% T gamma, 63% Tmu) in PBL. Normal age- and sex-matched controls PBL had 74% total T cells (20% T gamma, 54% Tmu). By direct observation using an indirect immunofluorescence assay, 41% of the CSF T gamma cells in MS patients bore receptors for IgM; these cells were designated T gamma mu and, according to the double-marker analysis, did not seem to correlate with disease stage. In MS PBL, 20% of T gamma cells were T gamma mu compared to 9% in the control PBL T gamma population. Thus, MS patients had a higher proportion of total T cells, T gamma cells and T gamma mu cells in their CSF than in their peripheral blood and than those populations found in normal control blood. The significance of this T gamma mu population for the continuing disease state in MS is discussed.  相似文献   
6.
Cerebrospinal fluid (CSF) and serum from 19 patients with mumps meningitis and 19 patients with meningitis of other etiology were investigated on two or more occasions for at least 1 month after onset. Intrathecal synthesis of immunoglobulin (Ig) G was found in 55%, of IgA in 26%, and of IgM in 24% of the patients. Oligoclonal Ig was demonstrable by agarose gel electrophoresis in 37% of the patients, mostly already during the first week after onset, and could persist for years. Mumps virus antibody synthesis within the central nervous system occurred in 37% of the mumps meningitis patients. The inflammatory reaction within the central nervous system as reflected by mononuclear pleocytosis, Ig synthesis, and oligoclonal Ig was not correlated to the clinical course. The blood-brain barrier was evaluated by determination of the CSF total protein, CSF/serum albumin ratio, and CSF/serum alpha2-macroglobulin ratio. A significant correlation was found among these three parameters. Persistence of the elevated CSF/serum albumin ratio seems to influence prognosis, and this parameter is recommended for evaluation of the blood-brain barrier function.  相似文献   
7.
Summary Experimental infection with HVJ (haemagglutinating virus of Japan—the Sendai strain of parainfluenza 1 virus) in mice was studied. Aerosol infection of newborn mice with the wild-type virus (HVJ-W) retarded the development of body weight and killed the animals within a few weeks. Large amounts of virus were isolated from both the lungs and the nasal turbinates of infected mice. In contrast, newborn mice exposed by inhalation to a temperature-sensitive(ts) mutant (HVJ-pB) derived from an HVJ carrier culture showed no clinical signs and grew equally well as mock-infected animals. No infectious virus could be recovered from the lungs although thets mutant grew to moderate titre in the nasal turbinates.The prior inoculation of newborn mice with thets mutant virus induced a state of significant resistance to subsequent challenge with the virulent wild-type virus.No replication of challenge virus in both lungs and nasal turbinates could be detected and the animals were protected a lethal infection. It is suggested that an avirulent temperature-sensitive mutant which has lost the capacity to replicate in the lower respiratory tract but is still capable of multiplying in the nasal turbinates may be a promising candidate for use in live vaccines especially against the infectious disease of the lower respiratory tract.With 2 Figures  相似文献   
8.
Togashi  T.  Örvell  C.  Vartdal  F.  Norrby  E. 《Archives of virology》1981,67(2):149-157
Summary Mouse hybridoma cell lines were produced by fusion of P3 × 63 Ag8 myeloma cells with spleen cells from BALB/c mice immunized with purified measles virions. About 60 per cent of single cell colonies in wells were found to produce measles antibodies as determined by a radioimmune assay. Selected measles antibody producing hybridoma cell lines were passaged intraperitoneally in mice and ascites fluids were collected. This material contained 20–200 times higher antibody titers than unconcentrated medium from hybridoma cell lines propagated in tissue culture. The ascites fluid antibody products of 23 hybridoma cell lines were characterized by different measles serological tests. Seventeen lines produced high titers of hemagglutination inhibiting (HI) and hemolysis-inhibition (HLI) antibodies. One hybridoma cell line produced Ig with low HI but high HLI activity and the remaining 5 hybridoma cell line products only carried HLI activity. Unexpectedly it was found in radioimmune precipitation assays that all hybridomas studied, including those showing HLI but no HI antibody activity, gave a selective precipitation of the 79K measles hemagglutinin polypeptide. Radioimmune precipitation assays with sera from immunized animals showed that they contained high titers of antibodies precipitating the 79 K polypeptide but in addition also somewhat lower titers of antibodies precipitating the 60 K nucleoprotein, 40 K fusion and 36 K matrix polypeptides. Homogeneous Ig products carrying measles antibody activity were demonstrated by imprint immunoelectrophoresis of ascites materials.With 2 Figures  相似文献   
9.
Two partially overlapping 19 and 22 amino acids long peptides representing a highly immunogenic site of the transmembranous glycoprotein (gp41) of human immunodeficiency virus (HIV) were used as antigen in ELISA tests. The results of antibody determination with this assay were compared with those of three or more conventional ELISAs and Western blot (WB) tests and radioimmunoprecipitation assay. Twenty-six sera from patients with AIDS or LAS and from asymptomatic carriers of HIV infection all showed a pronounced reaction in the peptide ELISA as well as positive results with other tests. In contrast, 27 sera from laboratory workers and blood donors were negative by all tests. A group of 39 blood donor sera, which had shown false positive or ambiguous results in the ELISAs and sometimes in WB tests employed for confirmation, also were negative in all cases with the peptide ELISA. Consecutive samples collected from individuals with primary HIV infection were also analyzed. In 6 out of 9 cases, the peptide ELISA revealed an antibody response within one month after onset of clinical symptoms and sensitivity for antibody detection equaled that of other ELISA tests. Eight sera from five West African persons infected with HIV-related viruses did not react in the peptide ELISA, reflecting differences in properties of the envelope components. The peptide ELISA used in this study appears to represent a simple technique employing chemically synthesized antigen for accurate and sensitive estimation of antibodies to the HIV group of nontransforming human retroviruses.  相似文献   
10.
Summary Pairs of dogs were immunized with 2 injections of a) measles virus material containing hemagglutinin but no hemolysin [Tween 80 and ether (TE) treated] b) material containing both hemagglutinin and hemolysin (freeze-dried and heated at 95° C for 30 minutes), and c) live measles virus. Two unimmunized dogs were used as controls. All 8 dogs were challenged with virulent canine distemper virus (CDV). The two unimmunized dogs contracted a lethal infection, whereas immunized animals only showed mild signs of infection. Preimmunization with TE treated antigen gave the weakest protection. The animals displayed fever between day 4 and 10 after challenge. All titers of preexisting antibodies were boosted and antibodies against the measles hemolysin and CDV neutralizing antibodies increased from undetectable to moderate levels. Non-infectious intact virus (b) gave a more pronounced antibody response than TE antigen but antibodies against the hemolysin could not be detected. There was a good protection against disease (limited fever response). Replication of CDV caused a raise of antibody titers to levels normally seen only under conditions of hyperimmunization. Live measles virus stimulated the production of antibodies against both envelope components, but in spite of this virulent CDV could multiply and boost the titers of all antibodies.Abbreviations CDV canine distemper virus - TE Tween 80 and ether - SPF specific pathogen free - PHA phytohemagglutinin - HLI hemolysis inhibition - HI hemagglutination inhibition - NC-CF nucleocapsid complement fixation With 1 FigureThis work was supported by grants from the Swedish Medical Research Council (Project no. 16x–116) and by US Public Health Service grant 1 1201 NS 14342-01A1 from the National Institute of Neurological and Communicative Disorders and Stroke.  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-23

京公网安备 11010802026262号