全文获取类型
收费全文 | 8243篇 |
免费 | 344篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 188篇 |
儿科学 | 244篇 |
妇产科学 | 106篇 |
基础医学 | 1363篇 |
口腔科学 | 133篇 |
临床医学 | 415篇 |
内科学 | 1985篇 |
皮肤病学 | 167篇 |
神经病学 | 587篇 |
特种医学 | 295篇 |
外科学 | 1338篇 |
综合类 | 24篇 |
预防医学 | 144篇 |
眼科学 | 107篇 |
药学 | 487篇 |
中国医学 | 24篇 |
肿瘤学 | 1048篇 |
出版年
2023年 | 41篇 |
2022年 | 92篇 |
2021年 | 203篇 |
2020年 | 96篇 |
2019年 | 124篇 |
2018年 | 156篇 |
2017年 | 139篇 |
2016年 | 162篇 |
2015年 | 161篇 |
2014年 | 233篇 |
2013年 | 291篇 |
2012年 | 479篇 |
2011年 | 574篇 |
2010年 | 328篇 |
2009年 | 248篇 |
2008年 | 425篇 |
2007年 | 499篇 |
2006年 | 506篇 |
2005年 | 539篇 |
2004年 | 567篇 |
2003年 | 526篇 |
2002年 | 605篇 |
2001年 | 116篇 |
2000年 | 70篇 |
1999年 | 111篇 |
1998年 | 135篇 |
1997年 | 135篇 |
1996年 | 112篇 |
1995年 | 79篇 |
1994年 | 99篇 |
1993年 | 101篇 |
1992年 | 70篇 |
1991年 | 70篇 |
1990年 | 58篇 |
1989年 | 51篇 |
1988年 | 48篇 |
1987年 | 42篇 |
1986年 | 45篇 |
1985年 | 36篇 |
1984年 | 39篇 |
1983年 | 23篇 |
1982年 | 32篇 |
1981年 | 25篇 |
1980年 | 30篇 |
1979年 | 14篇 |
1978年 | 24篇 |
1977年 | 11篇 |
1976年 | 17篇 |
1974年 | 8篇 |
1973年 | 11篇 |
排序方式: 共有8655条查询结果,搜索用时 0 毫秒
61.
Goya S Matsuoka H Mori M Morishita H Kida H Kobashi Y Kato T Taguchi Y Osaki T Tachibana I Nishimoto N Yoshizaki K Kawase I Hayashi S 《The Journal of pathology》2003,200(1):82-87
A variety of pathological changes are seen in lymphoproliferative disorders of the lung but the histogenesis of these abnormalities is not yet fully understood. We previously showed that adenovirus vector-mediated transient expression of both the human interleukin-6 (IL-6) and IL-6 receptor (IL-6R) genes, but not the IL-6 gene alone, in the rat lung induced lymphocytic alveolitis. In the present study, we explored the lung pathology of human IL-6 and IL-6R double transgenic mice to elucidate the effects of prolonged IL-6 signalling on the lung. The transgenic animals developed mononuclear cell accumulation in peribronchovascular regions, but little infiltration into alveolar spaces. Immunohistochemical analysis revealed that the cellular accumulations contained not only mixtures of inflammatory cells but also lymphoid tissue-like structures. As the expression of CXCL13/BLC, the indispensable chemokine for lymphoid organogenesis, was recognized in the B cell follicles of the pulmonary lesions, we speculate that this chemokine plays an inductive role in the development of the lymphoid tissue-like structures. These structures were distinguished from bronchus-associated lymphoid tissues (BALTs) by their location and by the lack of lymphoepithelium, which is a characteristic of BALT. These findings imply that IL-6 signalling may play a role in the pathogenesis of lymphoproliferative disorders of the lung. 相似文献
62.
Takahashi HK Morichika T Iwagaki H Tamura R Kubo S Yoshino T Mori S Akagi T Tanaka N Nishibori M 《Clinical immunology (Orlando, Fla.)》2003,108(3):274-281
Lipopolysaccharide (LPS) binds to LPS-binding protein (LBP) in plasma and is delivered to the cell surface receptor CD14 on human monocyte. LPS is transferred to the transmembrane signaling receptor toll-like receptor (TLR) 4. In the present study, the effect of histamine on the expression of CD14 on human monocytes was investigated. Histamine concentration- and time-dependently decreased the expression of cell surface CD14, whereas histamine did not decrease mRNA for CD14 nor increase soluble CD14 (sCD14). The inhibitory effects of histamine on CD14 expression were antagonized by H2-receptor antagonist, but not by H1 and H3/H4 antagonist. The effects of selective H2-receptor agonists, 4-methylhistamine and dimaprit, on CD14 expression mimicked that of histamine indicating that histamine regulated CD14 expression through the stimulation of H2-receptors. The pretreatment with histamine partially inhibited the LPS-induced TNF-alpha production in human peripheral blood mononuclear cells (PBMC). Such inhibition might be due to the down-regulation of CD14 expression on monocytes by histamine. 相似文献
63.
Association of HLA alleles with response (especially biochemical response) to interferon therapy in Japanese patients with chronic hepatitis C. 总被引:1,自引:0,他引:1
Shuhei Nishiguchi Satoshi Kaneshiro Motoharu Tanaka Masaru Enomoto Tamori Akihiro Daiki Habu Tadashi Takeda Keizo Fujino Takashi Tanaka Yoshihisa Yano Susumu Shiomi 《Journal of interferon & cytokine research》2003,23(3):135-141
The response of chronic hepatitis C to interferon (IFN) treatment is classified as complete response (CR), biochemical response (BR), or no response (NR). Several studies have found no difference in prevention of hepatocellular carcinoma by IFN therapy between patients with CR and those with BR. We investigated whether specific human leukocyte antigen (HLA) alleles were associated with response to IFN, especially BR, in 138 patients with chronic hepatitis C. Comparing patients with and without CR, male, a low viral titer, genotype 2a or 2b, HLA-B55, and HLA-DRB1-0803 were more common in the group with CR. Multivariate analysis showed that age (adjusted odds ratio [OR], 0.95 by every year [95% confidence interval [CI] 0.90 - 0.99], p = 0.028), genotype 2a or 2b (5.21 [95% CI 1.63 - 16.6], p = 0.005), and low viral titer (8.58 (2.66 - 27.7), p < 0.001) were associated with CR. Comparing patients with BR and NR, the pretreatment alanine aminotransferase (ALT) level was lower in the BR group (p < 0.001). Both HLA-B7 and HLA-DRB1-0101 were more common in this group (p = 0.002). As the alleles HLA-B7 and HLA-DRB1-0101 were in linkage disequilibrium, the HLA-B7-DRB1-0101 haplotype may be associated with BR. Multivariate analysis indicated that a low ALT level (0.98 by every 1 IU/L [95% CI 0.98 - 0.99], p = 0.001) and HLA-B7-DRB1-0101 haplotype (32.3 [95% CI 1.50 - 693.1], p = 0.026) contributed significantly to BR. This study suggested that host HLA expression, but not viral factors, can influence BR. 相似文献
64.
Tadashi Narita Tokio Hagiwara Hiroshi Hamana Takehiko Miyasaka Akira Wakayama Tetsuo Hotta 《Macromolecular chemistry and physics.》1987,188(2):273-279
The anionic polymerizations of 2,2,2-trifluoroethyl acrylate ( 1a ), 2,2,2-trifluoroethyl methacrylate ( 1b ), 2,2,2-trifluoro-1-trifluoromethylethyl acrylate ( 2a ), and 2,2,2-trifluoro-1-trifluoromethylethyl methacrylate ( 2b ) were examined with triethylaluminium and diethylaluminium active methylene chelate compounds as initiators. 2b was polymerized with triethylaluminium. Diethyl(ethyl cyanoacetato)aluminium was found to produce polymers of 1a and 1b . Diethyl(acetylacetonato)aluminium and diethyl (dimethyl malonato)aluminium, however, show low reactivity towards these four monomers. The resulting polymers show unimodal molecular weight distribution with number-average molecular weights of 104?105, measured by GPC. The initiation reaction and the copolymerization reactivity with styrene support the anionic polymerization mechanism. 相似文献
65.
66.
Tanaka K Tamura J Kawanabe K Nawa M Uchida M Kokubo T Nakamura T 《Journal of biomedical materials research. Part A》2003,67(1):200-207
Recently zirconia/alumina composites have been examined by many researchers as the new generation of bearing materials in total joint replacements. In this study, the phase stability of a Ce-TZP/Al(2)O(3) nanocomposite and conventional Y-TZP after aging, and its influence on wear resistance, were investigated. Very slight phase transformation was observed in both types of ceramics 18 months after the implantation of Ce-TZP/Al(2)O(3) or Y-TZP samples into rabbit tibiae. However, Y-TZP showed marked phase transformation (approximately 80%) after aging in an autoclave (121 degrees C) for 190 h or in physiological saline at 62 degrees C for 18 months, whereas the new composite remained almost resistant to degradation. According to the results of self-pairing pin-on-disk wear tests using ceramic specimens with or without autoclave aging, the wear factor was almost the same between Ce-TZP/Al(2)O(3) samples with and without aging (6.74 +/- 0.36 x 10(-8) and 6.04 +/- 0.95 x 10(-8) mm(3)/Nm, respectively). In contrast, although non-aged Y-TZP had the lowest wear factor (4.88 +/- 0.51 x 10(-8) mm(3)/Nm) of all specimens tested, aged Y-TZP showed 10-fold greater wear than nonaged Y-TZP. The present study suggests that Ce-TZP/Al(2)O(3) nanocomposite has much greater phase stability than Y-TZP, and that its wear properties are not influenced by aging. 相似文献
67.
Follicular hyperplasia presenting with a marginal zone pattern in a reactive lymph node lesion 总被引:1,自引:0,他引:1
Kojima M Nakamura S Motoori T Shimizu K Ohno Y Itoh H Masawa N 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2002,110(4):325-331
Histologically, the marginal zone pattern of the lymph node is characterized by lymphoid follicles with three distinct layers. The inner layer is composed of follicular center zones, the middle layer of darkly stained mantle zones, and the outer layer of marginal zones. However, the marginal zone pattern is rarely seen in reactive lymph nodes except for mesenteric lymph nodes. We describe the clinicopathologic, immunohistochemical and genotypic findings of six cases of reactive follicular hyperplasia exhibiting the marginal zone pattern. The patients comprised three males and three females (age range 24 to 63 years; medium 56 years). Follow-up data were obtained from five patients. None of them developed malignant lymphomas during the follow-up period of from 5 to 204 months (median 68 months). Histologically, the lesion was characterized by numerous lymphoid follicles and partial distortion of lymph node structure. Varying degrees of progressive transformation of the germinal center (PTGC) were noted in the four cases. The marginal zone pattern was observed in some or most of the lymphoid follicles including PTGC. The marginal zone B cells were small to medium-sized lymphocytes with round or slightly indented nuclei and a broad rim of pale cytoplasm. Some of them had a monocytoid appearance. They were CD20+, CD79a+, sIgM+/-, sIgD-, CD5-, CD10-, CD21-, CD23-, CD43-, CD45RO-, Bcl-6-, cyclin D1-, EMA- and p53-. A portion of them were Bcl-2 positive. Occasional large lymphoid cells with round or indented nuclei and moderate amounts of cytoplasm were observed in the marginal zone in four cases. These large lymphoid cells were usually CD20 positive, but Bcl-6 negative. A small number of them contained polytypic intracytoplasmic immunoglobulins. The polytypic nature of B lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. Recognition of unusual marginal zone hyperplasia in reactive lymph node lesions is important to avoid confusion with nodal involvement in various low-grade B cell lymphomas presenting a marginal zone distribution pattern. 相似文献
68.
Tochigi M Umekage T Kato C Marui T Otowa T Hibino H Otani T Kohda K Kato N Sasaki T 《Psychiatric genetics》2005,15(1):67-69
A number of studies have observed associations between the serotonin 2A (5-HT2A) receptor and mental disorders. Here, we investigated correlations between polymorphisms (-1438G/A and 102T/C) of the 5-HT2A gene and personality traits in healthy Japanese volunteers (n = 239). The personality traits were evaluated using the Revised NEO Personality Inventory (NEO PI-R). The -1438G/A and 102T/C were in complete linkage disequilibrium. There was a tendency for associations between the genotype and the scores for Agreeableness, Conscientiousness and Neuroticism of the NEO PI-R (P = 0.028, 0.039 and 0.062, respectively; analysis of variance, uncorrected for multiple testing). Subjects with the A/A of -1438G/A (or T/T of 102T/C) appeared to be lower in Neuroticism and higher in Conscientiousness than the rest of the subjects. However, the results were statistically non-significant after Bonferroni's correction for multiple testing of the five scales of the NEO PI-R. Thus, the present study provided no evidence for statistically significant associations between the 5-HT2A polymorphisms and the personality traits. 相似文献
69.
Mitsui A Hamuro J Nakamura H Kondo N Hirabayashi Y Ishizaki-Koizumi S Hirakawa T Inoue T Yodoi J 《Antioxidants & redox signaling》2002,4(4):693-696
Transgenic (Tg) mice overexpressing human thioredoxin (TRX), a small redox-active protein, were produced to investigate the role of the protein in a variety of stresses. Bone marrow cells from TRX-Tg mice were more resistant to ultraviolet C-induced cytocide compared with those from wild type (WT) C57BL/6 mice. TRX-Tg mice exhibited extended median and maximum life spans compared with WT mice. Telomerase activity in spleen tissues in TRX-Tg mice was higher than that in WT mice. These results suggest that overexpression of TRX results in resistance against oxidative stress and a possible extension of life span without apparent abnormality in mammals. 相似文献
70.
Masafumi Takahashi Uichi Ikeda Kazuyuki Shimada Tadashi Kasahara Sei-Ichi Kitagawa Yu-Ichi Takahashi Chikao Morimoto Shogo Kano Jun-Ichi Masuyama 《Journal of clinical immunology》1997,17(1):53-62
Interleukin-8 (IL-8) is a chemokine for polymorphonuclear leukocytes (PMNs) and lymphocytes, which promotes the extravasation of these inflammatory cells. In this study, we investigated IL-8 synthesis induced by the adhesive interaction between monocytes and endothelial cells during transmigration and the capacity of transmigrated monocytes to produce IL-8. Cocultured human monocytes and human umbilical vein endothelial cell (HUVEC) monolayers induced the synefgistic production of IL-8, compared with cultures of either monocytes or HUVEC monolayers alone. Coculture-induced IL-8 production almost doubled after HUVECs were stimulated with IL-1. The induced IL-8 mRNA expression was consistent with the protein data, indicating the de novo synthesis of IL-8 by the coculture. Monoclonal antibodies (mAbs) against IL-8 inhibited the transendothelial chemotactic activity of the supernatants for PMNs by 55%. Immunohistochemistry revealed that both adherent and transmigrated monocytes and unstimulated HUVECs expressed IL-8 protein, whereas nonadherent monocytes did little. Transmigrated monocytes spontaneously secreted a 3.8-fold greater amount of IL-8 than the initial monocytes. Coculture-induced IL-8 production was inhibited about 30% by polyclonal Abs against IL-, IL-1, or tumor necrosis factor , while it was not affected by mAbs against intercellular adhesion molecule 1 or vascular cell adhesion molecule 1. The results suggested that adhesive interaction during the transmigration of monocytes through HUVEC monolayers activates both cell types to produce IL-8 and that transmigrated monocytes are capable of producing ample IL-8. 相似文献