全文获取类型
收费全文 | 59933篇 |
免费 | 5551篇 |
国内免费 | 4265篇 |
专业分类
耳鼻咽喉 | 614篇 |
儿科学 | 549篇 |
妇产科学 | 576篇 |
基础医学 | 6886篇 |
口腔科学 | 1202篇 |
临床医学 | 7835篇 |
内科学 | 8588篇 |
皮肤病学 | 674篇 |
神经病学 | 2637篇 |
特种医学 | 1927篇 |
外国民族医学 | 41篇 |
外科学 | 6038篇 |
综合类 | 10736篇 |
现状与发展 | 19篇 |
一般理论 | 14篇 |
预防医学 | 4559篇 |
眼科学 | 1672篇 |
药学 | 6397篇 |
66篇 | |
中国医学 | 3496篇 |
肿瘤学 | 5223篇 |
出版年
2024年 | 238篇 |
2023年 | 936篇 |
2022年 | 2368篇 |
2021年 | 3185篇 |
2020年 | 2357篇 |
2019年 | 1946篇 |
2018年 | 2075篇 |
2017年 | 1835篇 |
2016年 | 1696篇 |
2015年 | 2840篇 |
2014年 | 3409篇 |
2013年 | 2969篇 |
2012年 | 4283篇 |
2011年 | 4750篇 |
2010年 | 3293篇 |
2009年 | 2668篇 |
2008年 | 3190篇 |
2007年 | 3187篇 |
2006年 | 3170篇 |
2005年 | 3056篇 |
2004年 | 2256篇 |
2003年 | 2100篇 |
2002年 | 1710篇 |
2001年 | 1455篇 |
2000年 | 1353篇 |
1999年 | 1371篇 |
1998年 | 923篇 |
1997年 | 865篇 |
1996年 | 639篇 |
1995年 | 668篇 |
1994年 | 558篇 |
1993年 | 328篇 |
1992年 | 370篇 |
1991年 | 334篇 |
1990年 | 289篇 |
1989年 | 248篇 |
1988年 | 203篇 |
1987年 | 198篇 |
1986年 | 133篇 |
1985年 | 114篇 |
1984年 | 65篇 |
1983年 | 37篇 |
1982年 | 22篇 |
1981年 | 27篇 |
1980年 | 8篇 |
1979年 | 22篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
运用敏感的B_9细胞增殖试验检测了81例多发性骨髓瘤(MM)患者血清IL-6活性,同时分析了标本的几种急性相蛋白含量,结果表明,68%MM患者血清中IL-6活性大于5μ/ml(正常对照为5μ/ml以下),几种急性相蛋白中C-反应性蛋白(CRP)在MM时升高(P<0.01),平均达正常对照组的17倍以上,MM患者补体C_4与正常对照组无差异(p>0.05),C_3、白蛋白及转铁蛋白在MM时分别比正常下降24.42%、38.83%和32.80%,且与疾病分期有关,在血清IL-6大于5μ/ml的55例中,IL-6活性与CRP、C_3、白蛋白的相关系数分别为0.46,-0.34和-0.29,IL-6与转铁蛋白浓度相关不明显。本文结果提示:CRP、C_3及白蛋白等含量的变化可作为反映MM病情的简易而敏感的指标。 相似文献
82.
Favorably tipping the balance between cytopathic and regulatory T cells to create transplantation tolerance 总被引:23,自引:0,他引:23
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
83.
84.
85.
The discovery and confirmation of single nucleotide polymorphisms in the human p53R2 gene by EST database analysis 总被引:2,自引:0,他引:2
The human expressed sequence tag (EST) database provides a wealth of resources, which can be used to rapidly screen for potential polymorphisms in proteins of physiological interest. The human p53R2 gene, a recently identified ribonucleotide reductase, plays an important role in DNA repair and is involved in the pathway of p53 activity in response to the presence of DNA damage. On the basis of the alignment of human EST sequences, we identified three candidate polymorphisms at nt 2752, 2759 and 4696 in the 3'-untranslated region of the p53R2 gene. The presence of these polymorphisms was confirmed in a Caucasian population (n = 82) by allele-specific PCR and PCR/restriction fragment length polymorphism analyses. The rare allele frequency at position 4696 (15.5%) is higher than either rare allele frequency at position 2752 or 2759 (6 and 6%). Our results suggest that the human EST data may serve as a valuable source for the rapid identification of genetic variation. 相似文献
86.
In this study, a human adult testis cDNA microarray was constructed and hybridized with (33)P-labeled human adult testis, embryo testis and sperm cDNA probes, respectively. A novel alternative splice variant of BRDT gene, named BRDT-NY, presumably involved in testicular function was cloned. It was expressed 3.96-fold more in human adult than embryo testis and also expressed in human spermatozoa. Similarly, RT-PCR revealed a differential expression pattern of this gene in human adult testes and fetal testes. The full length of BRDT-NY was 3438 bp and contained a 2883 bp open reading frame, encoding a 960-amino-acid protein. Sequence analysis showed that it has two bromodomains in N-terminal of the protein. Multiple tissue RT-PCR results showed that BRDT-NY was exclusively expressed in testis. mRNA expression of BRDT-NY gene was deleted in some azoospermic patients' testes. These experiments suggested that BRDT-NY gene may have an important role in the process of spermatogenesis and may be correlated with male infertility. 相似文献
87.
Zheng L Zomerdijk TP Van Den Barselaar MT Geertsma MF Van Furth R Nibbering PH 《Immunology》1999,98(1):90-97
Since arachidonic acid (AA) production by phospholipase A2 (PLA2) is essential for the Fcgamma receptor (FcgammaR)-mediated respiratory burst and phagocytosis of opsonized erythrocytes by monocytes and macrophages, we focused in this study on the role of AA and its metabolites in the FcgammaR-stimulated intracellular killing of Staphylococcus aureus by human monocytes. The results revealed that the PLA2 inhibitors, but not inhibitors of cyclo-oxygenase and lipoxygenase, markedly suppressed the FcgammaR-mediated killing process. The production of O-2 by monocytes upon FcgammaR cross-linking was inhibited by 4-bromophenacyl bromide in a dose-dependent fashion, indicating that inhibition of PLA2 activity impairs the oxygen-dependent bactericidal mechanisms of monocytes, which could be partially restored by addition of exogenous AA and docosahexaenoic acid, but not myristic acid. These polyunsaturated fatty acids, but not myristic acid, stimulated the intracellular killing of S. aureus by monocytes, although not as effectively as FcgammaR cross-linking. Furthermore, FcgammaR cross-linking stimulated the release of AA from monocytes. Studies with selective inhibitors revealed that the FcgammaR-mediated activation of PLA2 is dependent on Ca2+ and tyrosine kinase activity. Together these results indicate a key role for PLA2/AA, but not its major metabolites, in mediating the FcgammaR-stimulated intracellular killing of S. aureus by monocytes. 相似文献
88.
89.
Simplified purification of human basophils 总被引:7,自引:0,他引:7
Tsang S Hayashi M Zheng X Campbell A Schellenberg RR 《Journal of immunological methods》2000,233(1-2):13-20
Studies of human basophils have been limited by the low number present in peripheral blood and the difficulties of purification to homogeneity with reasonable yield and functional status. Reproducible purification of human basophils to 96.5+/-0.5% with a yield of 40.8+/-5.3% was obtained by negative selection using immunomagnetic beads following initial separation by density gradient centrifugation. Isolated cells demonstrated complete viability by vital dye exclusion and spontaneous histamine release following incubation of <5%. Stimulation with anti-IgE or calcium ionophore A23187 caused histamine release and leukotriene C(4) production. Basophils demonstrated dose-dependent chemotaxis to monocyte chemotactic protein-3. This simplified methodology results in fully functional basophils in very high purity and good yield. 相似文献
90.
Plasmids encoding foot-and-mouth disease virus VP1 epitopes elicited immune responses in mice and swine and protected swine against viral infection 总被引:20,自引:0,他引:20
VP1 is a capsid protein of foot-and-mouth disease virus (FMDV) and contains epitopes of the virus. Plasmids encoding two VP1 epitopes (amino acid residues 141-160 and 200-213) and a host-self immunoglobulin molecule were constructed to produce a new type of FMD DNA vaccine. Two plasmids, namely, pCEIM and pCEIS, containing mouse immunoglobulin (IgG) or swine IgG were subjected to immunogenicity testing in mice and swine, respectively. In mice administrated pCEIM in the abdomen using a genegun, both FMDV-specific T-cell proliferation and neutralizing antibodies were detected. In swine immunized with pCEIS at the back of the ear, immune responses were achieved after the second administration. Swine showed a T-cell proliferative response with a stimulation index (SI) of up to 8.1 and a neutralizing antibody response that was able to protect suckling mice from 10(2) LD(50) (lethal dose 50) FMDV challenge. To compare the immunogenicity of the DNA-based vaccine candidate, versus the protein-based vaccine candidates, a second group of swine was immunized with the protein F1-scIgG, which was encoded by the plasmid pCEIS. Injection with F1-scIgG elicited a T-cell proliferative response of SI < 1.7 and a neutralizing antibody response that protected suckling mice from up to 10(5) LD(50) FMDV challenge. In the challenge test, three of three swine immunized with pCEIS were fully protected from FMDV challenge. 相似文献