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   296篇
  免费   23篇
  国内免费   2篇
儿科学   12篇
妇产科学   2篇
基础医学   50篇
口腔科学   19篇
临床医学   33篇
内科学   58篇
皮肤病学   11篇
神经病学   21篇
特种医学   18篇
外科学   39篇
综合类   10篇
预防医学   16篇
眼科学   6篇
药学   9篇
中国医学   1篇
肿瘤学   16篇
  2023年   3篇
  2021年   3篇
  2020年   3篇
  2019年   3篇
  2018年   7篇
  2017年   4篇
  2016年   8篇
  2015年   5篇
  2014年   10篇
  2013年   17篇
  2012年   10篇
  2011年   11篇
  2010年   6篇
  2009年   9篇
  2008年   7篇
  2007年   14篇
  2006年   11篇
  2005年   14篇
  2004年   21篇
  2003年   15篇
  2002年   2篇
  2001年   9篇
  2000年   3篇
  1999年   5篇
  1998年   13篇
  1997年   10篇
  1996年   11篇
  1995年   7篇
  1994年   5篇
  1993年   5篇
  1992年   4篇
  1991年   7篇
  1990年   6篇
  1989年   3篇
  1988年   6篇
  1987年   8篇
  1986年   3篇
  1985年   9篇
  1984年   1篇
  1983年   3篇
  1982年   6篇
  1981年   3篇
  1980年   2篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1954年   1篇
排序方式: 共有321条查询结果,搜索用时 0 毫秒
91.
92.
93.
Among 39, 656 voluntary blood donors in Okinawa Prefecture, Japan, 115 (0.29%) were repeatedly reactive for antibody to hepatitis C virus (anti-HCV) by second generation (2nd-gen) passive hemagglutination assay (PHA). Positive serum samples were tested for anti-HCV using three different enzyme immunosorbent assays (ELISAs; Abbott 2nd EIA, UBI-HCV-EIA, JCC-2) and for HCV-RNA by the polymerase chain reaction (PCR). The 115 2nd-gen PHA-positive sera were divided into three groups according to the agglutination titers; >210 (high titer group), 27?29 (median), 25?26 (low). All but one serum (44/45) in the high PHA titer group reacted in each of the three second screening ELISAs. Furthermore, 43 (97.7%) of the 44 sera contained HCV-RNA by PCR. In the median titer group, 11 of the 13 samples tested were positive by each of the three ELSIAs, and 4 (36.4%) of the 11 showed reaction by PCR. On the other hand, all of the 38 sera tested in the low titer group were negative for HCV-RNA by PCR, and 24 of the 38 were also negative by each of the three ELISAs. Most of the low titer positive reactions in the 2nd-gen agglutination assay seemed to be false positive. In Okinawa Prefecture, the prevalence of anti-HCV among blood donors is much lower than in the rest of Japan (0.29% vs. 1.11%). Moreover, a significant proportion of these sera were low titer by the PHA assay. The difference in the genuine anti-HCV-positive rate, or the prevalence of HCV carriage between Okinawa Prefecture and the rest of Japan may therefore be even greater than is presently assumed. © 1995 Wiley-Liss, Inc.  相似文献   
94.
BACKGROUND: Human papilloma virus (HPV) is the most important factor in the oncogenic mechanism of cervical tumor. Furthermore, in a separate multi-stage process, abnormality in cell cycle kinetics has been demonstrated. In order to elucidate the oncogenic mechanism, we examined the relationship between cervical carcinoma and HPV infection, and also investigated the expression of p53 and p21 proteins as well as the cell proliferation capability by detecting Ki-67, and analyzed the correlations of these factors. MATERIALS AND METHODS: We studied the biopsy specimens from 107 patients of chronic cervicitis, cervical intraepithelial neoplasia and squamous cell carcinoma (SCC). HPV DNA was detected by the hybrid capture method. Immunostaining by LSAB procedures were performed using antibodies to p53 protein, p21 and MIB-1. The PCR-denaturing gradient gel electrophoresis (DGGE) method was used to search for mutation in exons 5, 6, 7 and 8 of p53. RESULTS: Of 107 cases studied, high-oncogenic HPV was detected in 80 cases (74.8%) with a particularly high prevalence in SCC. No correlation was observed between HPV infection and expression of p53, p21 or Ki-67. The degree of positivity of Ki-67 expression tended to be higher with disease progression. Cases strongly positive (2+) for p53 and p21 proteins were weakly positive for Ki-67, and cases positive (1+) or negative for p53 and p21 were strongly positive for Ki-67. CONCLUSION: In oncogenesis of cervical carcinoma, p53 protein, p21 protein and HPV may act separately as independent factors in some cases, and there is a strong possibility that other factors are involved.  相似文献   
95.
The primary site for the growth and differentiation of B cell precursors in irradiated recipient mice was investigated. Bone marrow (BM) cells from lipopolysaccharide (LPS)-responder C57BL/6 mice were transferred into irradiated LPS-nonresponder C57BL/10ScCr mice, and the generation of donor-derived B cells in the recipient was monitored by determining the immunoglobulin-producing cells developed in the LPS-stimulated cultures of recipient's spleen cells as well as BM cells. As previously stated, the transfer of fresh BM cells resulted in the development of LPS-reactive cells both in spleen and BM simultaneously. On the other hand, when long-term cultured BM cells which were shown to be devoid of B cells and pre-B cells were used as the donor cells, the development of LPS-reactive cells was first observed only in BM, and subsequently in both BM and spleen. The failure to detect LPS-reactive cells in the spleen in the early phase, or day 11 after irradiation and reconstitution, was not attributed to the culture condition or the existence of suppressive activity in day 11 spleen cells. These results indicate that B cell precursors lodge only in the BM of irradiated recipients, grow and differentiate in the same place, and then the differentiated progeny migrate to peripheral lymphoid organs.  相似文献   
96.
The usual methods for pathological diagnosis of HPV infection of the uterine cervix include screening in cytodiagnosis and histodiagnosis and confirmation by immunohistochemistry (IHC) method. However, some institutes have recently begun to use in situ hybridization (ISH) method for definitive diagnosis using a DNA probe. We compared IHC with ISH with regards to the localization and rate of detection of HPV in lesions of the uterine cervix such as dysplasia and squamous cell carcinoma in the present study. The cases found positive by IHC showed brownish nuclei of the epithelium and those positive in ISH showed purple to purplish-black nuclei. The comparison of cases positive by both methods revealed that the number of cells positive by IHC was smaller than that by ISH, and the cells positive by IHC were localized in the superficial layer. HPV was detected by the IHC various lesions of the uterine cervix in 13 (12.3%) of 106 patients, while it was detected by the ISH in 39 (36.8%) of 106 patients. The results of both methods were in accordance in 66.0% (77 patients; positively in 8 and negatively in 62). The detection sensitivity of IHC is lower than that of ISH. IHC cannot be used to identify the type of HPV, and it is impossible to confirm the presence or absence of virus by this method in cases of malignant changes. ISH is therefore necessary for identification of HPV and investigation of a histopathological relationship between HPV type and malignant change.  相似文献   
97.
BACKGROUND: Recent data indicate high prevalence of both anxiety and substance comorbidity in bipolar disorder. However, few studies have utilized public sector samples, and only one has attempted to separate contributions of each type of comorbidity. METHODS: 328 inpatient veterans with bipolar disorder across 11 sites were assessed using selected Structured Clinical Interview for DSM-IV modules and self-reports. RESULTS: Comorbidity was common (current: 57.3%; lifetime: 78.4%), with multiple current comorbidities in 29.8%. Substance comorbidity rate was comparable to rates typically reported in non-veteran inpatient samples (33.8% current, 72.3% lifetime). Selected anxiety comorbidity rates exceeded those in other inpatient samples and appeared more chronic than episodic/recurrent (38.3% current, 43.3% lifetime). 49% of PTSD was due to non-combat stressors. Major correlates of current substance comorbidity alone were younger age, worse marital status, and higher current employability. Correlates of current anxiety comorbidity alone were early age of onset, greater number of prior-year depressive episodes, higher rates of disability pension receipt, and lower self-reported mental and physical function. Combined comorbidity resembled anxiety comorbidity. LIMITATIONS: This is a cross-sectional analysis of acutely hospitalized veterans. CONCLUSIONS: Distinct patterns of substance and anxiety comorbidity are striking, and may be subserved by distinct neurobiologic mechanisms. The prevalence, chronicity and functional impact of anxiety disorders indicate the need for improved recognition and treatment of this other dual diagnosis group is warranted. Clinical and research interventions should recognize these divergent comorbidity patterns and provide individualized treatment built "from the patient out."  相似文献   
98.
99.
100.
From a surface active fraction of porcine lung lavage fluid, separated by discontinuous sucrose density gradient ultracentrifugation, a protein with a nominal molecular weight (MW) of 15,000 daltons was isolated by sequential extraction with several buffers, including one containing deoxycholate. A monoclonal antibody was prepared from a hybrid cell (8B5E) obtained by fusing a myeloma cell, X63.Ag8.653, with spleen cells of BALB/c mice immunized with the protein. With immunoblotting technique, the antibody was found to be specific to the 15,000 dalton protein and did not react with another surfactant-associated protein with a nominal MW of 38,000 daltons. The antibody's IgG subclass was IgG1 and the light chain was kappa. In immunohistochemical studies using biotinylated antibody, peroxidase reaction products were localized selectively at inclusions of alveolar wall cells which were located chiefly at the alveolar corners. These results strongly suggest that this 15,000 dalton protein was localized in inclusions of alveolar wall cells and did not originate from other larger surfactant-associated proteins degraded after secretion into alveolar space.  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