全文获取类型
收费全文 | 7117篇 |
免费 | 329篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 140篇 |
妇产科学 | 241篇 |
基础医学 | 1073篇 |
口腔科学 | 124篇 |
临床医学 | 569篇 |
内科学 | 1460篇 |
皮肤病学 | 151篇 |
神经病学 | 844篇 |
特种医学 | 438篇 |
外国民族医学 | 1篇 |
外科学 | 775篇 |
综合类 | 48篇 |
一般理论 | 1篇 |
预防医学 | 546篇 |
眼科学 | 60篇 |
药学 | 571篇 |
2篇 | |
中国医学 | 15篇 |
肿瘤学 | 356篇 |
出版年
2021年 | 100篇 |
2020年 | 54篇 |
2019年 | 92篇 |
2018年 | 104篇 |
2017年 | 89篇 |
2016年 | 110篇 |
2015年 | 136篇 |
2014年 | 179篇 |
2013年 | 227篇 |
2012年 | 341篇 |
2011年 | 325篇 |
2010年 | 210篇 |
2009年 | 204篇 |
2008年 | 280篇 |
2007年 | 289篇 |
2006年 | 278篇 |
2005年 | 303篇 |
2004年 | 264篇 |
2003年 | 264篇 |
2002年 | 297篇 |
2001年 | 220篇 |
2000年 | 233篇 |
1999年 | 223篇 |
1998年 | 92篇 |
1997年 | 76篇 |
1996年 | 52篇 |
1995年 | 70篇 |
1994年 | 61篇 |
1992年 | 95篇 |
1991年 | 79篇 |
1990年 | 102篇 |
1989年 | 126篇 |
1988年 | 115篇 |
1987年 | 97篇 |
1986年 | 112篇 |
1985年 | 118篇 |
1984年 | 71篇 |
1983年 | 71篇 |
1979年 | 91篇 |
1978年 | 64篇 |
1977年 | 65篇 |
1976年 | 58篇 |
1975年 | 60篇 |
1974年 | 50篇 |
1973年 | 75篇 |
1972年 | 61篇 |
1971年 | 77篇 |
1970年 | 59篇 |
1969年 | 59篇 |
1968年 | 51篇 |
排序方式: 共有7464条查询结果,搜索用时 15 毫秒
51.
52.
ICAM-1, VCAM-1, and MAdCAM-1 are expressed on choroid plexus epithelium but not endothelium and mediate binding of lymphocytes in vitro. 总被引:4,自引:2,他引:4 下载免费PDF全文
B. J. Steffen G. Breier E. C. Butcher M. Schulz B. Engelhardt 《The American journal of pathology》1996,148(6):1819-1838
The expression of cell adhesion molecules (CAMs) in the choroid plexus was studied in normal brain and during experimental autoimmune encephalomyelitis (EAE) in the SJL/J mouse during inflammation induced by intracerebral injection of killed Corynebacterium parvum in the C3H/He mouse. Both ICAM-1 and VCAM-1, but not MAdCAM-1, were constitutively expressed on choroid plexus epithelium but not on the fenestrated capillary endothelial cells within the choroid plexus. During EAE, we observed an up-regulation of ICAM-1 and VCAM-1 and de novo expression of MAdCAM-1 on choroid plexus epithelial cells. In contrast, endothelial cells in the choroid plexus were not induced to express any of the investigated CAMs. In in situ hybridization analysis we demonstrated that ICAM-1, VCAM-1, and MAdCAM-1 were locally synthesized and that the amount of their mRNAs increased in the inflamed choroid plexus. In vitro, primary choroid plexus epithelial cells could be induced to express ICAM-1, VCAM-1, and MAdCAM-1 on their surface after treatment with proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1, interferon-gamma, and lipopolysaccharide. To investigate the functional status of the expressed CAMs we performed Stamper-Woodruff binding assays on frozen sections of inflamed and naive brains. ICAM-1, VCAM-1, and MAdCAM-1 expressed in choroid plexus epithelial cells mediated binding of lymphocytes via their known ligands LFA-1 and alpha4-integrin, respectively. The expression of ICAM-1, VCAM-1, and MAdCAM-1 on choroid plexus epithelial cells together with the lack of their expression on the fenestrated choroid plexus endothelium raises the possibility that the epithelial blood-cerebrospinal-fluid barrier plays an important role in the immunosurveillance of the central nervous system. 相似文献
53.
Schatz O Monini P Bugarini R Neipel F Schulz TF Andreoni M Erb P Eggers M Haas J Buttò S Lukwiya M Bogner JR Yaguboglu S Sheldon J Sarmati L Goebel FD Hintermaier R Enders G Regamey N Wernli M Stürzl M Rezza G Ensoli B 《Journal of medical virology》2001,65(1):123-132
A multicentre study was undertaken to define novel assays with increased inter-assay concordance, sensitivity, specificity and predictive value for serological diagnosis of human herpesvirus type 8 (HHV-8) infection. A total of 562 sera from European and Ugandan human immunodeficiency virus (HIV)-infected or uninfected individuals with or without Kaposi's sarcoma (KS) and blood donors were examined under code by 18 different assays in seven European laboratories. Sera from KS patients and all non-KS sera found positive by at least 70%, 80%, or 90% of the assays were considered "true positive." The validity of the assays was then evaluated by univariate logistic regression analysis. Two immunofluorescence assays (IFA) for detection of antibodies against HHV-8 lytic (Rlyt) or latent (LLANA) antigens and two enzyme-linked-immunosorbent assays (ELISA) (M2, EK8.1) for detection of antibodies against HHV-8 structural proteins were found to be highly concordant, specific, and sensitive, with odds ratios that indicated a high predictive value. When used together, the two IFA (Rlyt-LLANA) showed the best combination of sensitivity (89.1%) and specificity (94.9%). The performance of these assays indicate that they may be used for the clinical management of individuals at risk of developing HHV-8 associated tumours such as allograft recipients. 相似文献
54.
W. Schröter E. Schulz R. Bonn 《Journal of molecular medicine (Berlin, Germany)》1970,48(16):1013-1014
Zusammenfassung Bei 16 von 17 Patienten mit Osteomyelofibrose wurden in den Erythrocyten erhöhte Konzentrationen an reduziertem Glutathion nachgewiesen. Die Bestimmung des Glutathions kann als differentialdiagnostisch wertvolles Kriterium für die Charakterisierung der Osteomyelofibrose angesehen werden.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
Summary In 16 of 17 patients with osteomyelofibrosis the concentration of erythrocyte reduced glutathione was increased. It is concluded that the determination of erythrocyte glutathione is of differential diagnostic value in the characterization of osteomyelofibrosis.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
55.
T cell reactivity in neonates from an East and a West German city--results of the LISA study 总被引:1,自引:0,他引:1
Lehmann I Thoelke A Weiss M Schlink U Schulz R Diez U Sierig G Emmrich F Jacob B Belcredi P Bolte G Heinrich J Herbarth O Wichmann HE Borte M 《Allergy》2002,57(2):129-136
BACKGROUND: Within an ongoing birth cohort study (LISA) the cytokine production of cord blood T cells was compared between neonates from Leipzig (East Germany) and Munich (West Germany). The aim of this study was to analyse regional differences and influencing factors of the immune status. METHODS: Cytokine production was measured in a randomly selected subgroup of 158 children from the LISA (Life style - Immune system - Allergy) cohort by intracellular cytokine staining. Information on family "atopy" history (FAH) and home characteristics was obtained from questionnaires. RESULTS: Reduced numbers of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) producing T cells were found in association with biparental FAH and housing renovation during pregnancy. In addition, cytokine production was influenced by season. In Munich, the frequency of biparental FAH and of renovation measures during pregnancy was significantly higher as compared to Leipzig. Neonates from Munich showed significantly decreased amounts of IFN-gamma and TNF-alpha and elevated levels of interleukin-4 (IL-4) producing T cells. Differences in cytokine production between Munich and Leipzig were influenced by season (IL-4) and housing renovation (IFN-gamma, TNF-alpha). CONCLUSIONS: Since differences in the T cell cytokine production of neonates in Munich and Leipzig are independent from FAH our findings may provide evidence for the impact of environmental factors upon the fetal immune system. 相似文献
56.
SUMMARY The wavelet transform is a relatively new approach to data processing which has been applied in different areas such as signal, speech and image processing. In the last decade, many papers have been published on wavelet theory and its applications. The wavelet transform provides an elegant alternative to the classical Fourier or Gabor transforms unifying numerous signal processing techniques in a common framework. The purpose of the present paper is to provide an overview of the applicability of the wavelet transform to EEG signal analysis. In the first part of the paper the mathematical background is summarized. In the second part, applications to the sleep EEG field are presented and discussed. The results of these illustrations demonstrate the usefulness of the wavelet transform to solve various problems including signal parametrization, pattern recognition and biosignal representation. 相似文献
57.
No increased human herpesvirus 8 seroprevalence in patients with HIV-associated non-Hodgkin's lymphoma 总被引:1,自引:0,他引:1
Gérard L Agbalika F Sheldon J Maillard A Schulz TF Oksenhendler E 《Journal of acquired immune deficiency syndromes (1999)》2001,26(2):182-184
Human herpesvirus 8 (HHV-8) is closely associated with Kaposi's sarcoma (KS), HIV-associated Castleman's disease, and primary effusion lymphoma. As a high frequency of non-Hodgkin's lymphoma (NHL) has been reported in patients with HIV-associated KS, we hypothesized that HHV-8 infection could be indirectly implicated in the pathogenesis of NHL. We assessed the prevalence of HHV-8 antibodies in 63 patients with NHL compared with 126 HIV-infected matched control patients without NHL. Serum samples from cases and controls were assayed for antibodies to HHV-8 lytic and latent antigens using an indirect immunofluorescence assay. In patients with concordant serologic results, HHV-8 antibodies were detected in 41.5% of the NHL cases and 37% of the controls. This absence of a significant difference in HHV-8 seroprevalence between cases and controls (p =.73) does not support a possible role for HHV-8 infection in the development of NHL in HIV-infected patients. 相似文献
58.
59.
60.
Immunohistochemical study of osteonectin in various types of osteosarcoma. 总被引:2,自引:0,他引:2 下载免费PDF全文
A. Schulz G. Jundt K. H. Berghuser P. Gehron-Robey J. D. Termine 《The American journal of pathology》1988,132(2):233-238
Polyclonal antibodies against osteonectin, a 32 kd non-collagenous bone protein, were applied for the histogenetic identification of variously differentiated osteosarcoma tissues. A strong positive reaction was found in matrix-producing osteosarcoma cells of the osteoblastic type, but pleomorphic or fibrosarcomatous osteosarcoma tissues reacted focally positive as well. Because the production of osteonectin depends on the osteoblastlike function of the individual tumor cell, a homogeneous immunocytochemical staining of all tumor cells cannot be expected. Nevertheless, the immunocytochemical demonstration of osteonectin in osteolytic tumors that produce no or scarcely any matrix seems to be a valuable tool for establishment of their osteogenic origin. 相似文献