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   23838篇
  免费   1332篇
  国内免费   176篇
耳鼻咽喉   273篇
儿科学   710篇
妇产科学   745篇
基础医学   2446篇
口腔科学   678篇
临床医学   2075篇
内科学   5029篇
皮肤病学   434篇
神经病学   1112篇
特种医学   843篇
外国民族医学   11篇
外科学   4392篇
综合类   412篇
现状与发展   2篇
一般理论   12篇
预防医学   1917篇
眼科学   658篇
药学   2045篇
中国医学   161篇
肿瘤学   1391篇
  2024年   19篇
  2023年   283篇
  2022年   859篇
  2021年   1275篇
  2020年   689篇
  2019年   893篇
  2018年   1227篇
  2017年   711篇
  2016年   765篇
  2015年   765篇
  2014年   1166篇
  2013年   1314篇
  2012年   1961篇
  2011年   2130篇
  2010年   1192篇
  2009年   858篇
  2008年   1276篇
  2007年   1280篇
  2006年   1186篇
  2005年   1079篇
  2004年   973篇
  2003年   879篇
  2002年   822篇
  2001年   167篇
  2000年   124篇
  1999年   121篇
  1998年   105篇
  1997年   101篇
  1996年   96篇
  1995年   81篇
  1994年   75篇
  1993年   64篇
  1992年   56篇
  1991年   62篇
  1990年   63篇
  1989年   55篇
  1988年   56篇
  1987年   48篇
  1986年   40篇
  1985年   45篇
  1984年   46篇
  1983年   38篇
  1982年   39篇
  1981年   28篇
  1980年   31篇
  1978年   17篇
  1977年   19篇
  1976年   17篇
  1974年   17篇
  1973年   20篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
71.
72.
Ring-stage parasitized erythrocytes (RPEs) were demonstrated to interact with effector cells of the innate immune system. With receptor blockade studies and CD36-null macrophages, human and murine macrophages were shown to phagocytose RPEs through the pattern recognition receptor CD36. These in vitro data implicate scavenger receptors in the clearance of RPEs.  相似文献   
73.
Therapeutic application of broadly reactive anti-T cell antibodies can lead not only to potent immunosuppression but also to profound and long-lived T cell depletion. We reasoned that a strategy that almost exclusively targets activated cytopathic donor reactive T cells and spares immunoregulatory networks might prove to be an exceptionally potent and highly selective means of producing long-term engraftment and tolerance. Herein we show that the combined administration of rapamycin and agonist IL-2- and antagonist IL-15-related cytolytic fusion proteins provides for long-term engraftment/tolerance in exceptionally stringent allotransplant models by (1) limiting the early expansion of activated T cells, (2) preserving and even exaggerating their subsequent apoptotic clearance, and (3) further amplifying the depletion of these activated T cells by antibody-dependent mechanisms, while (4) preserving CD4+CD25+ T cell-dependent immunoregulatory networks.  相似文献   
74.
Toll-like receptors (TLR) have a key role in regulating immunity against microbial agents. Engagement of TLR by bacterial, viral or fungal components leads to the production and release of inflammatory cytokines. In this study we show that mainly TLR8 and also TLR7 act as the host sensors for human parechovirus 1, a single-stranded RNA (ssRNA) virus. Furthermore, we see that the viral ssRNA genome is detected in endosomal compartments by these TLR, which activate signalling that lead to the synthesis of pro-inflammatory molecules by the host.  相似文献   
75.
DicomWorks is freeware software for reading and working on medical images [digital imaging and communication in medicine (DICOM)]. It was jointly developed by two research laboratories, with the feedback of more than 35,000 registered users throughout the world who provided information to guide its development. We detail their occupations (50% radiologists, 20% engineers, 9% medical physicists, 7% cardiologists, 6% neurologists, and 8% others), geographic origins, and main interests in the software. The viewer’s interface is similar to that of a picture archiving and communication system viewing station. It provides basic but efficient tools for opening DICOM images and reviewing and exporting them to teaching files or digital presentations. E-mail, FTP, or DICOM protocols are supported for transmitting images through a local network or the Internet. Thanks to its wide compatibility, a localized (15 languages) and user-friendly interface, and its opened architecture, DicomWorks helps quick development of non proprietary, low-cost image review or teleradiology solutions in developed and emerging countries.  相似文献   
76.
BACKGROUND: Aerosolization of fish proteins during seafood processing has been identified as a potential route for allergic sensitization and occupational asthma among workers involved in high-risk activities. The aim of this study was to develop immunological assays for the quantification of aerosolized fish antigens in a fish-processing factory. METHODS: Polyclonal antibodies to the main fish species processed in the factory (anchovy and pilchard) were generated in rabbits and compared by ELISA inhibition assay and immunoblotting. These antisera were utilized to develop ELISA assays for the detection of fish antigens. The ELISA inhibition assays were evaluated by analyzing environmental air samples collected from three areas in a fish-processing factory: pilchard canning, fish meal production and lobster processing. RESULTS: By immunoblotting, the rabbit polyclonal antibodies demonstrated IgG antibody binding patterns comparable with IgE antibodies of fish-sensitized patients, particularly in regard to the major fish allergens parvalbumins. The sensitivity of the fish-specific ELISA assays developed was 0.5 microg/ml. The ELISA inhibition assays were able to differentiate between the two different fish species of interest but did not recognize a crustacean species. Notable differences in exposure levels to canned pilchard and anchovy antigens were demonstrated in the three different working areas of the factory, with assays having a detection limit as low as 105 ng/m(3). CONCLUSION: These ELISA-based assays are sensitive and specific to quantify differential exposure levels to fish antigens produced during fish processing, making it possible to investigate exposure-disease response relationships among workers in this industry.  相似文献   
77.
New macromers 4, 8, and 10, containing ester, alcohol, or acid functions, were prepared starting with vinyl chloride (CV) or vinylidene dichloride (CV2). The telomer 1, resulting from CV2 and CCI4 was telomerized with allyl acetate and the product was transformed into the acrylate 4 by hydrolysis of the reaction product and subsequent esterification. Macromers 8 and 10 were prepared from CV by radical telomerization with thioglycolic acid (7) and 2-mercaptoethanol (9), respectively. Reactive double bonds were introduced into these macromers by reaction with acrylic acid, Vinyl chloroformate, methacryloyl chloride, or 2,3 -epoxypropyle methacrylate, leading to new macromers 12, 13, 14, and 15, respectively.  相似文献   
78.
Cytogenetic analyses of 16 cases of Wilms tumor with abnormal karyotypes were reviewed, 15 cases of unilateral tumor and 1 bilateral. Three tumors exhibited an unfavorable histology (i.e., anaplastic changes); the rest fell into the favorable histology group. Of the 17 tumors with abnormal clonal aberrations, 9 tumors were hyperdiploid (53%), 7 had pseudodiploid karyotypes (41%), and 1 was hypodiploid (6%). The most common numerical aberrations in descending order of frequency were gain of chromosomes 12, 8, and 6 and loss of chromosome 16. Structural rearrangements mostly involved chromosome 1, followed by chromosomes 7, 14, and 17. Clustering of breaks around 1p22 approximately p31-->pter resulting in partial loss of 1p was the most frequent structural aberration. Additionally, i(7q) was observed as a sole abnormality in two tumors and a 7p translocation in two other tumors. Two other recurrent abnormalities were a partial deletion of 14q, seen in three tumors, and complete loss of chromosome 14 in one tumor. All three Wilms tumors with unfavorable histology had abnormalities of 17p, resulting in TP53 gene deletion. These findings provide further support for the importance of gains of chromosomes 12, 8, and 6 and loss of 1p in the development of Wilms tumor. The results also support the association of unfavorable-histology Wilms tumors with TP53 deletion. The nonrandom losses of 16/16q, 7p, and 14q may point to the importance of genomic imbalance in the pathogenetic consequences and progression of Wilms tumor.  相似文献   
79.
HLA class II polymorphism in Moroccan IDDM patients has not been investigated so far. In this study, HLA-DRB1, -DQA1, and -DQB1 allele and haplotype frequencies were analyzed in 125 unrelated Moroccan IDDM patients and 93 unrelated healthy controls, all originating from the Souss region and mostly of Berber origin. Some common features with other Caucasian groups were observed, in particular, a predisposing effect of the DRB1*03-DQA1*0501-DQB1*0201 and DRB1*04-DQA1*0301-DQB1*0302 alleles or allelic combinations. The Moroccan IDDM group also presented with more specific characteristics. Among DRB1*04 subtypes, DRB1*0405 was associated with susceptibility to and DRB1*0406 with protection from the disease. The haplotype and the relative predispositional effect (RPE) analyses indicated that the DRB1*08-DQA1*0401DQB1 *0402 haplotype was also associated with susceptibility to IDDM. Interestingly, the DRB1*09DQA1 *0301-DQB1*0201 haplotype, completely absent from the control group and very rare in North African populations, was observed in 7.2% of the Moroccan diabetics. Conversely, the DRB1*07-DQA1*0201DQB1 *0201 and DRB1*15-DQA1*0102-DQB1*0602 haplotypes were associated with protection from IDDM. Finally, we observed an age-dependent genetic heterogeneity of IDDM, the frequencies of predisposing alleles being higher and those of protective alleles lower in childhood- than in adult-onset diabetics. Our data on Moroccan diabetics, together with data on European and Northern Mediterranean patients, suggest a gradient of various HLA class II predisposing and protective markers that link these populations  相似文献   
80.
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