全文获取类型
收费全文 | 294544篇 |
免费 | 7074篇 |
国内免费 | 156篇 |
专业分类
耳鼻咽喉 | 2922篇 |
儿科学 | 11918篇 |
妇产科学 | 7063篇 |
基础医学 | 32972篇 |
口腔科学 | 4424篇 |
临床医学 | 20906篇 |
内科学 | 53451篇 |
皮肤病学 | 4054篇 |
神经病学 | 25600篇 |
特种医学 | 14196篇 |
外国民族医学 | 32篇 |
外科学 | 48355篇 |
综合类 | 3924篇 |
一般理论 | 29篇 |
预防医学 | 24091篇 |
眼科学 | 6272篇 |
药学 | 17784篇 |
2篇 | |
中国医学 | 971篇 |
肿瘤学 | 22808篇 |
出版年
2018年 | 22799篇 |
2017年 | 18121篇 |
2016年 | 20582篇 |
2015年 | 2168篇 |
2014年 | 2457篇 |
2013年 | 3211篇 |
2012年 | 10167篇 |
2011年 | 24221篇 |
2010年 | 20790篇 |
2009年 | 13457篇 |
2008年 | 22765篇 |
2007年 | 25188篇 |
2006年 | 4274篇 |
2005年 | 6028篇 |
2004年 | 7184篇 |
2003年 | 7989篇 |
2002年 | 6100篇 |
2001年 | 7404篇 |
2000年 | 7526篇 |
1999年 | 6125篇 |
1998年 | 1859篇 |
1997年 | 1786篇 |
1996年 | 1446篇 |
1995年 | 1330篇 |
1994年 | 1214篇 |
1993年 | 1209篇 |
1992年 | 3902篇 |
1991年 | 3725篇 |
1990年 | 3774篇 |
1989年 | 3513篇 |
1988年 | 3143篇 |
1987年 | 3022篇 |
1986年 | 2884篇 |
1985年 | 2722篇 |
1984年 | 2017篇 |
1983年 | 1686篇 |
1982年 | 980篇 |
1981年 | 953篇 |
1980年 | 822篇 |
1979年 | 1871篇 |
1978年 | 1399篇 |
1977年 | 1147篇 |
1976年 | 968篇 |
1975年 | 1229篇 |
1974年 | 1294篇 |
1973年 | 1232篇 |
1972年 | 1094篇 |
1971年 | 1025篇 |
1970年 | 938篇 |
1969年 | 838篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
M. Knappik U. Börner T. Jelinek 《European journal of clinical microbiology & infectious diseases》2005,24(10):701-703
The study presented here was conducted to evaluate the performance of the newly available RIDASCREEN Set (R-Biopharm AG, Darmstadt,
Germany) for the detection of immunoglobulin G antibodies against Entamoeba histolytica. The sensitivity and specificity of this new enzyme-linked immunosorbent assay were evaluated using a panel of sera from
239 individuals. The assay was positive for 43 of 44 patients with invasive amebiasis, including all 18 patients with amebic
liver abscess, while it was negative for 190 of 195 adult controls who were either healthy individuals or patients with other
parasitic diseases. The kit was found to be highly specific (97.4%) and sensitive (97.7%) for detecting antibodies against
E. histolytica in humans. Although antibody titers in patients with amebic liver abscess tend to be higher on average than in patients with
invasive amebiasis, it is not possible to distinguish the two forms solely based on the results of this commercial test. 相似文献
52.
T. Saarne L. Kaiser H. Grönlund O. Rasool G. Gafvelin M. van Hage-Hamsten 《Clinical and experimental allergy》2005,35(5):657-663
BACKGROUND: Allergen-specific immunotherapy is the only treatment for allergic disease providing long-lasting symptom relief. Currently, it is mainly based on the use of crude allergen extracts. The treatment may be improved by the use of genetically engineered allergens, hypoallergens, aiming at a more effective and safer therapy. OBJECTIVE: The aim of this study was to provide a rational design of hypoallergen candidates for immunotherapy by using structural information and knowledge of B and T cell epitopes of an allergen. METHODS: The three-dimensional structure of the major cat allergen Fel d 1 was systematically altered by duplication of selected T cell epitopes and disruption of disulphide bonds. Seven Fel d 1 derivatives were generated and screened for allergenic reactivity in comparison with recombinant Fel d 1 in competition-ELISA. The allergenicity was further evaluated in basophil activation experiments and T cell reactivity was assessed in a lymphoproliferation assay. RESULTS: Three out of seven Fel d 1 derivatives, with two duplicated T cell epitopes and one or two disulphide bonds disrupted, were carefully evaluated. The three derivatives displayed a strong reduction in allergenicity with 400-900 times lower IgE-binding capacity than recombinant Fel d 1. In addition, they induced a lower degree of basophil activation and similar or stronger T cell proliferation than recombinant Fel d 1. CONCLUSION: By a rational approach, we have constructed three Fel d 1 hypoallergens with reduced IgE-binding capacities and retained T cell reactivities. This strategy may be applied to any well-characterized allergen to improve immunotherapy for allergic patients. 相似文献
53.
The detection of antineuronal antibodies against cytoplasm and nuclei of Purkinje cells is considered to be an essential factor in the diagnosis of neurologic paraneoplastic syndromes. Published data rely on different immunological methods and relatively small numbers of patients. The clinical relevance of this phenomenon is not clear from the literature. A positive correlation between antibody detection and the appearance of neurologic paraneoplastic syndromes has been reported, but this finding has been questioned in critical reviews. 相似文献
54.
Summary A necrotizing, nonprogressive myopathy with unusual paracrystalline inclusion bodies is described in a patient who underwent long-term treatment with megadoses of vitamin E. The clinical course and morphological findings suggest a close relationship to the administration of the vitamin. The theoretical pathogenesis of muscle damage and the possible origin of paracrystalline inclusion bodies are discussed.Presented at the Jahrestagung der österreichischen Gesellschaft für Neuropathologie in Bad Ischl, on April 17, 1986This study was supported by a grant from the Deutsche Forschungsgemeinschaft (Ba 916) 相似文献
55.
P B Schneider U Denk M Breitenbach K Richter P Schmid-Grendelmeier S Nobbe M Himly A Mari C Ebner B Simon-Nobbe 《Clinical and experimental allergy》2006,36(12):1513-1524
BACKGROUND: Alternaria alternata is one of the most important allergenic fungi worldwide. Mannitol dehydrogenase (MtDH) has previously been shown to be a major allergen of Cladosporium herbarum and cross-reactivity has been demonstrated for several fungal allergens. OBJECTIVE: The present study's objective was to clone the MtDH from an A. alternata cDNA library, express and purify the recombinant non-fusion protein and test its IgE-binding properties. Methods A cDNA library prepared from A. alternata hyphae and spores was screened for mannitol dehydrogenase by DNA hybridization with the radioactively labelled C. herbarum homologue as a probe. The resulting clone was sequenced and heterologously expressed in Escherichia coli as a recombinant non-fusion protein, which was purified to homogeneity and analysed for its IgE-binding capacity. RESULTS: The coding sequence of the full-length cDNA clone comprises 798 bp encoding a protein with a molecular mass of 28.6 kDa and a predicted pI of 5.88. Protein sequence analysis revealed an identity of 75% and a homology of 86% between the MtDHs of A. alternata and C. herbarum. The functional mannitol dehydrogenase was expressed in the E. coli strain BL21(DE3) transformed with the vector pMW172 and purified to homogeneity. The enzyme catalyses the NADPH-dependent conversion of d-fructose to d-mannitol. In IgE-ELISA and immunoblots, MtDH is recognized by 41% of A. alternata-allergic patients. In vivo immunoreactivity of the recombinant MtDH was verified by skin prick testing. Finally, inhibition-ELISA experiments confirmed cross-reactivity between the MtDHs of A. alternata and C. herbarum. CONCLUSION: Mannitol dehydrogenase (Alt a 8) represents an important new allergen of the ascomycete A. alternata that might be suitable for improving diagnostic and therapeutic procedures. 相似文献
56.
Henry Cisneros 《AIDS and behavior》2007,11(2):7-8
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference. 相似文献
57.
58.
Fire fighter helmet ventilation analysis 总被引:1,自引:0,他引:1
U Reischl 《American Industrial Hygiene Association journal》1986,47(9):546-551
A series of wind tunnel tests was conducted on selected fire fighter helmets to identify design factors which affect helmet ventilation at various air velocities and head orientation angles. Biomedical heat flux transducers were mounted on the surface of an electrically heated mannequin head to monitor convective heat loss. Under the experimental conditions, specific helmet design features were identified which can contribute to improved helmet ventilation and thus improve body metabolic heat loss. Attention to helmet design and helmet suspension systems is recommended to reduce fire fighter heat stress. 相似文献
59.
60.