全文获取类型
收费全文 | 4647篇 |
免费 | 338篇 |
国内免费 | 142篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 45篇 |
妇产科学 | 21篇 |
基础医学 | 1022篇 |
口腔科学 | 36篇 |
临床医学 | 208篇 |
内科学 | 631篇 |
皮肤病学 | 80篇 |
神经病学 | 796篇 |
特种医学 | 71篇 |
外国民族医学 | 1篇 |
外科学 | 260篇 |
综合类 | 361篇 |
预防医学 | 559篇 |
眼科学 | 83篇 |
药学 | 600篇 |
中国医学 | 87篇 |
肿瘤学 | 254篇 |
出版年
2024年 | 6篇 |
2023年 | 24篇 |
2022年 | 88篇 |
2021年 | 114篇 |
2020年 | 111篇 |
2019年 | 84篇 |
2018年 | 96篇 |
2017年 | 109篇 |
2016年 | 115篇 |
2015年 | 167篇 |
2014年 | 204篇 |
2013年 | 361篇 |
2012年 | 207篇 |
2011年 | 255篇 |
2010年 | 237篇 |
2009年 | 219篇 |
2008年 | 248篇 |
2007年 | 251篇 |
2006年 | 219篇 |
2005年 | 208篇 |
2004年 | 234篇 |
2003年 | 181篇 |
2002年 | 172篇 |
2001年 | 135篇 |
2000年 | 138篇 |
1999年 | 128篇 |
1998年 | 117篇 |
1997年 | 102篇 |
1996年 | 86篇 |
1995年 | 74篇 |
1994年 | 66篇 |
1993年 | 71篇 |
1992年 | 29篇 |
1991年 | 27篇 |
1990年 | 27篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 24篇 |
1985年 | 24篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 17篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 5篇 |
排序方式: 共有5127条查询结果,搜索用时 31 毫秒
61.
Mormyrid鱼电感受叶神经元的形态与电生理学特征韩中胜(HanZhongsheng)(LegacyGoodSamaritan,HospitalandMedicalCenter,RobertS.Dow,NeurologicalSciencesIns... 相似文献
62.
Ana J. Alarcos Jorge A. Etchegoin Florencia Cremonte 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2008,53(4):365-368
In this paper Steringotrema microacetabularis (Suriano et Martorelli, 1983) is redescribed and transferred to Bacciger Nicoll, 1924 in the Faustulidae Poche, 1926 based on newly collected material from the type-host, Paralichthys orbignyanus Valenciennes, 1839 and the type-locality, Mar Chiquita coastal lagoon, Buenos Aires Province, Argentina. A careful re-examination
of the new specimens shows that some anatomical characteristics were ignored or incompletely described by the previous authors
and they are included herein. The species is tentatively transferred to Bacciger with which it appears to have closest affinity. Despite the anatomical differences detailed in this paper, confirmation of
this proposal must await further work, including molecular studies. 相似文献
63.
František Moravec Sonia Ternengo Céline Levron 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2006,51(2):111-118
Gravid or subgravid females of the following three species belonging to the nematode genus Philometra were collected from marine perciform fishes of the Bonifacio Strait Marine Reserve, Corsica, France: Philometra justinei sp. nov. (prevalence 1.5%, intensity 11) and Philometra sp. (prevalence 3%, intensity 2) from the abdominal cavity and gonads, respectively, of the striped red mullet Mullus surmuletus (Mullidae), and Philometra serranellicabrillae Janiszewska, 1949 (prevalence 27%, intensity 2–6) from the gonads of the comber Serranus cabrilla (Serranidae). The newly described species, P. justinei, is mainly characterized by the absence of an anterior bulbous inflation of the oesophagus, body length of the gravid female
(196 mm), conspicuously large amphids, number and distribution of cephalic papillae, and the morphology of larvae. It is the
second known species of Philometra parasitizing fishes of the family Mullidae and the ninth species of this genus reported from marine fishes of the Mediterranean
region. P. serranellicabrillae, studied for the first time by SEM, is redescribed. 相似文献
64.
Tamauchi H Terashima M Ito M Maruyama H Ikewaki N Inoue M Gao X Hozumi K Habu S 《International immunology》2004,16(1):179-187
65.
Mageed RA Harmer IJ Wynn SL Moyes SP Maziak BB Brüggemann M MacKworth-Young CG 《Clinical and experimental immunology》2001,123(1):1-8
To formulate a 'logic' for how a single immunoglobulin variable region gene generates antibodies with different antigen specificity and polyreactivity, we analysed chimeric antibodies produced in transgenic mice carrying the germ-line human V3-23 gene, multiple diversity (D) and joining (J) gene segments. Hybridomas producing antibodies encoded by the V3-23 gene in combination with different mouse Vkappa genes were obtained by fusion of splenocytes from transgenic mice. All antibodies had human mu-chains and mouse light chains, were multimeric in structure and expressed the human V3-23 gene. Nucleotide sequence analyses of genes encoding the heavy and light chains of 12 antibodies in relation to antigen specificity highlighted the importance of heavy chain variable region CDR3 in determining reactivity with different antigens. However, the results also suggest that non-CDR3 sequences intrinsic to the V3-23 gene itself may be involved in, or determine, the binding of the chimeric antibodies to some of the antigens tested in the current study. 相似文献
66.
Masanori Kasahara E. Churchill McKinney Martin F. Flajnik Teruo Ishibashi 《European journal of immunology》1993,23(9):2160-2165
T cells recognize antigen (Ag) in the form of peptides bound to the major histocompatibility complex (MHC) molecule. One of the important issues in evolutionary immunology is to identify the stage in phylogeny when this mode of Ag recognition emerged. At present, there is a considerable controversy as to whether the cartilaginous fish have the bona fide MHC. In our previous study, we showed that the nurse shark, a member of the cartilaginous fish, has (a) gene(s) capable of encoding MHC class II a chains. In the present study, we examined the polymorphism of nurse shark MHC class II a chain genes designated Gici-DAA and Gici-DBA using the polymerase chain reaction. The Gici-DAA and Gici-DBA genes had six and five alleles, respectively, and individual alleles usually differed by multiple nucleotides. In addition, most of the nucleotide substitutions were located at the putative Ag-binding sites, where non-synonymous substitutions occurred more frequently than synonymous substitutions. The fact that the Gici-DAA and Gici-DBA genes display a polymorphism pattern essentially similar to that of mammalian MHC genes playing a major role in Ag presentation suggests that the cartilaginous fish have the bona fide MHC. Thus, the MHC-peptide-based T cell recognition system appears to have arisen at or before the emergence of the cartilaginous fish. 相似文献
67.
Transgenic mouse T cells expressing the human CD3 chain bindthe majority (29/36) of monoclonal antibodies (mAbs) specificfor human CD3. A proportion of these mAbs are also able to recognizeisolated CD3 in a soluble, recombinant form. Thus, CD3 can confermost CD3 epitopes on the TCR-CD3 complex, but many determinantsmay require assembly of the complex for their formation. A numberot mAbs did not recognize -transgenic T cells and probably needother CD3 subunits for binding. CD3-specific mAbs from eachof the three groups defined here, as well as mAbs directed againstthe TCRß heterodimer, are all able to activate T cells.Therefore mAb attachment at several different sites on the TCR-CD3complex can give rise to activation signals. This suggests thatthe cross-linking function of mitogenic antibodies may be theirmost significant property, rather than the perturbation of aparticular functional epitope. 相似文献
68.
Mathilde Chataigner Marie Martin Cline Lucas Veronique Pallet Sophie Lay Alexis Mehaignerie Elodie Bouvret Anne-Laure Dinel Corinne Joffre 《Nutrients》2021,13(3)
Neuroinflammation constitutes a normal part of the brain immune response orchestrated by microglial cells. However, a sustained and uncontrolled production of proinflammatory factors together with microglial activation contribute to the onset of a chronic low-grade inflammation, leading to neuronal damage and cognitive as well as behavioral impairments. Hence, limiting brain inflammatory response and improving the resolution of inflammation could be particularly of interest to prevent these alterations. Dietary n-3 long chain polyunsaturated fatty acids (LC-PUFAs) and low molecular weight peptides are good candidates because of their immunomodulatory and proresolutive properties. These compounds are present in a fish hydrolysate derived from marine-derived byproducts. In this study, we compared the effect of an 18-day supplementation with this fish hydrolysate to a supplementation with docosahexaenoic acid (DHA) on lipopolysaccharide (LPS)-induced inflammation in mice. In response to peripherally injected LPS, the fish hydrolysate supplementation decreased the hippocampal mRNA expression of the proinflammatory cytokines IL-6 (p < 0.001), IL-1β (p = 0.0008) and TNF-α (p < 0.0001), whereas the DHA supplementation reduced only the expression of IL-6 (p = 0.004). This decline in proinflammatory cytokine expressions was associated with an increase in the protein expression of IκB (p = 0.014 and p = 0.0054 as compared to the DHA supplementation and control groups, respectively) and to a modulation of microglial activation markers in the hippocampus. The beneficial effects of the fish hydrolysate could be due in part to the switch of the hippocampal oxylipin profile towards a more anti-inflammatory profile as compared to the DHA supplementation. Thus, the valorization of fish byproducts seems very attractive to prevent and counteract neuroinflammation. 相似文献
69.
Fedja A. Rochling 《Nutrients》2021,13(3)
The development of intestinal failure-associated liver disease (IFALD) in pediatric and adult patients on parenteral nutrition is usually multifactorial in nature due to nutritional and non-nutritional causes. The role of lipid therapy as a contributing cause is well-established with the pathophysiological pathways now better understood. The review focuses on risk factors for IFALD development, biological effects of lipids, lipid emulsions and the mechanisms of lipid toxicity observed in laboratory animals followed by a synopsis of clinical studies in pediatric and adult patients. The introduction of fish oil-based lipid emulsions that provide partial or complete lipid replacement therapy has resulted in resolution of IFALD that had been associated with soybean oil-based therapy. Based on case reports and cohort studies in pediatric and adult patients who were at risk or developed overt liver disease, we now have more evidence that an early switch to partial or complete fish oil–based lipid therapy should be implemented in order to successfully halt and reverse IFALD. 相似文献
70.
Xiaoyue Xu Zumin Shi Gang Liu Dennis Chang Sally C. Inglis John J. Hall Aletta E. Schutte Julie E. Byles Deborah Parker 《Nutrients》2021,13(3)
It is unknown whether a healthy diet or unhealthy diet combined with specific supplements may jointly contribute to incidence of obesity and cardiovascular disease (CVD). We included 69,990 participants from the 45 and Up Study who completed both baseline (2006–2009) and follow-up (2012–2015) surveys. We found that compared to participants with a long-term healthy diet and no supplement consumption, those with a long-term healthy diet combined with multivitamins and minerals (MVM) or fish oil consumption were associated with a lower incidence of CVD (p < 0.001); whilst those with an unhealthy diet and no MVM or fish oil consumption were associated with a higher risk of obesity (p < 0.05). Compared to participants with a long-term healthy diet and no calcium consumption, the combination of a long-term healthy diet and calcium consumption was linked to a lower risk of CVD (IRR = 0.87, 95% CI: 0.78; 0.96). In conclusion, a long-term healthy diet combined with MVM or fish oil was associated with a lower incidence of CVD. Participants who maintained a healthy diet and used calcium supplements were associated with a lower incidence of obesity. However, these associations were not found among those with an unhealthy diet, despite taking similar supplements. 相似文献