全文获取类型
收费全文 | 18220篇 |
免费 | 1395篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 550篇 |
妇产科学 | 509篇 |
基础医学 | 2680篇 |
口腔科学 | 342篇 |
临床医学 | 2091篇 |
内科学 | 3579篇 |
皮肤病学 | 325篇 |
神经病学 | 1919篇 |
特种医学 | 591篇 |
外科学 | 1731篇 |
综合类 | 158篇 |
现状与发展 | 1篇 |
一般理论 | 20篇 |
预防医学 | 1979篇 |
眼科学 | 284篇 |
药学 | 1420篇 |
中国医学 | 56篇 |
肿瘤学 | 1310篇 |
出版年
2024年 | 21篇 |
2023年 | 228篇 |
2022年 | 229篇 |
2021年 | 675篇 |
2020年 | 462篇 |
2019年 | 734篇 |
2018年 | 715篇 |
2017年 | 569篇 |
2016年 | 561篇 |
2015年 | 613篇 |
2014年 | 798篇 |
2013年 | 1032篇 |
2012年 | 1646篇 |
2011年 | 1556篇 |
2010年 | 802篇 |
2009年 | 757篇 |
2008年 | 1212篇 |
2007年 | 1222篇 |
2006年 | 1023篇 |
2005年 | 1084篇 |
2004年 | 936篇 |
2003年 | 803篇 |
2002年 | 761篇 |
2001年 | 121篇 |
2000年 | 60篇 |
1999年 | 98篇 |
1998年 | 125篇 |
1997年 | 121篇 |
1996年 | 71篇 |
1995年 | 69篇 |
1994年 | 64篇 |
1993年 | 54篇 |
1992年 | 41篇 |
1991年 | 30篇 |
1990年 | 37篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 35篇 |
1986年 | 32篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 26篇 |
1981年 | 21篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1975年 | 7篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Oral administration of insulin conjugated to the B chain of cholera toxin (CTB-insulin) in non-obese diabetic (NOD) mice results in diabetes prevention. We investigated the respective contributions of L-selectin (CD62L) and alpha4-integrin pathways during CTB-driven tolerance. Purified CD62L+CD4+ cells from CTB-insulin fed mice significantly reduced the capacity of diabetogenic T cells to transfer diabetes in syngeneic recipients. In vivo antibody blockade of fed animals during adoptive co-transfer experiments indicated that both CD62L and alpha4-integrins pathways were necessary to develop a protective response after oral tolerance induction. In contrast, when antibodies were given to recipient mice, only CD62L was critical for the protection. In vitro stimulated CD62L+CD4+ cells from the spleen of fed animals secreted lower amounts of IL-4 and IL-10 but comparable levels of TGFbeta than CD62L-cells. A reduced IFN-gamma production between the two cell subsets was specifically observed in CTB-insulin fed mice. Furthermore, antibody treatments induced changes in T-cell migration to the spleen, mesenteric and pancreatic lymph nodes. The protective effect was also associated with migration of regulatory T cells into pancreatic islets. Taken together, our results suggest that L-selectin and alpha4-integrin have distinct but complementary roles in the generation and function of regulatory CD4+ T cells following CTB-insulin administration. 相似文献
82.
This study was designed to investigate whether people who engage more frequently in healthy behaviours, and attach a higher value to health, are likely to engage less frequently in tattooing and piercing. One hundred and eight participants with tattoos and/or piercings completed questionnaires including the Reported Health Behaviours Checklist and the Health Value Scale. There were no significant relationships between healthy behaviours, health value and numbers of tattoos or piercings. A significant proportion of pierced and tattooed participants had not considered possible health risks, and those that had were often unaware of potentially serious health problems. Results are discussed in terms of health guidelines for tattooing and piercing. 相似文献
83.
The Role of APO-1-Mediated Apoptosis in the Immune System 总被引:12,自引:0,他引:12
84.
Relationship between Plasma Interleukin-12 (IL-12) and IL-18 Levels and Severe Malarial Anemia in an Area of Holoendemicity in Western Kenya 下载免费PDF全文
Sujittra Chaisavaneeyakorn Caroline Othoro Ya Ping Shi Juliana Otieno Sansanee C. Chaiyaroj Altaf A. Lal Venkatachalam Udhayakumar 《Clinical and Vaccine Immunology : CVI》2003,10(3):362-366
In this study, we investigated whether levels of interleukin-12 (IL-12) and IL-18 in plasma are associated with severe malarial anemia outcomes in an area of holoendemicity in western Kenya. We compared plasma IL-12 and IL-18 levels in six groups of children grouped into the categories aparasitemic, asymptomatic, mild malaria, high-density uncomplicated malaria (UC), moderate malarial anemia (MMA), or severe malarial anemia (SMA). IL-12 levels were significantly reduced in children with SMA (P < 0.05) but not in other groups compared to children in the aparasitemic control group. IL-18, a cytokine known to be critical for the induction of gamma interferon along with IL-12, was produced more frequently (70%) in children with UC (P = 0.06) than in children in the aparasitemic control group (32%). However, in the SMA group the IL-18 response rate declined to 30%, which was similar to that in the aparasitemic control group, which showed a 32% response rate. This finding suggests that the IL-18 response may be impaired in children with SMA. In summary, the results from this study support the hypothesis that impairment of IL-12 and/or IL-18 response may contribute to the development of severe malarial anemia in areas of holoendemicity for malaria. 相似文献
85.
The physical stability of virions of Cucumber mosaic virus (CMV) mutants was investigated to determine if relative stability correlated with efficiency of aphid transmission. Virion stability was evaluated by a urea disruption assay and by testing the infectivity of virus following purifications. All viruses were infectious when purified using a low salt buffer without organic solvent, whereas two of seven viruses were less stable and inactivated following purification with a high salt buffer and chloroform. These two viruses were both reassortants derived from the spontaneous transmission-defective mutant CMV-M (F1F2M3 and F1F2M3-L129P). F1F2M3 was relatively unstable, being disrupted between 0 and 1 M urea versus the wild-type CMV-Fny (F1F2M3) that was destabilized at 3-4 M urea. Modifications of F1F2M3 at three amino acid positions (129, 162, 168), singly or in combination, increased the relative stability of virions. A second class of transmission-defective CMVs with engineered mutations in the betaH-betaI surface loop of the CMV-Fny capsid protein (CP) exhibited near wild-type levels of stability. Lastly, a single Pro to Leu substitution at CP position 129 of CMV-Fny (F1F2M3-P129L) conferred the induction of necrosis in tobacco plants and reduced aphid transmissibility, but did not markedly alter the physical stability of virions. Thus, only among CMV-M derivatives harboring the CP mutation of Thr to Ala at position 162 were increases in stability correlated with restoration of transmissibility by the aphid Aphis gossypii. 相似文献
86.
Kathleen Rooney Caroline Hunt Leanne Humphreys David Harding Miriam Mullen John Kearney 《Clinical psychology & psychotherapy》2005,12(2):97-111
Prior reports suggest an ambivalence regarding treatment in individuals with Post-Traumatic Stress Disorder (PTSD). A model that accommodates such ambivalence is the Transtheoretical Model of Behavior Change (TTM, also known as the Stages-of-Change Model). Fifty veterans presenting for treatment completed self-report measures (94% response rate) that assessed disorder variables and constructs relating to the TTM. While the relationships between the components of each specific construct were found to be consistent with the findings of other studies and a number of predicted relationships between variables were confirmed, many results were inconsistent with the TTM. Notwithstanding questions about the suitability of the self-report measures, the unique characteristics of the veteran sample and the small sample size, the results suggest that the assumptions of the TTM were not met in veterans with PTSD. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
87.
Colland F Jacq X Trouplin V Mougin C Groizeleau C Hamburger A Meil A Wojcik J Legrain P Gauthier JM 《Genome research》2004,14(7):1324-1332
Access to the human genome facilitates extensive functional proteomics studies. Here, we present an integrated approach combining large-scale protein interaction mapping, exploration of the interaction network, and cellular functional assays performed on newly identified proteins involved in a human signaling pathway. As a proof of principle, we studied the Smad signaling system, which is regulated by members of the transforming growth factor beta (TGFbeta) superfamily. We used two-hybrid screening to map Smad signaling protein-protein interactions and to establish a network of 755 interactions, involving 591 proteins, 179 of which were poorly or not annotated. The exploration of such complex interaction databases is improved by the use of PIMRider, a dedicated navigation tool accessible through the Web. The biological meaning of this network is illustrated by the presence of 18 known Smad-associated proteins. Functional assays performed in mammalian cells including siRNA knock-down experiments identified eight novel proteins involved in Smad signaling, thus validating this integrated functional proteomics approach. 相似文献
88.
89.
Role for Fimbriae and Lysine-Specific Cysteine Proteinase Gingipain K in Expression of Interleukin-8 and Monocyte Chemoattractant Protein in Porphyromonas gingivalis-Infected Endothelial Cells 总被引:3,自引:0,他引:3 下载免费PDF全文
90.