全文获取类型
收费全文 | 5610篇 |
免费 | 299篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 118篇 |
妇产科学 | 27篇 |
基础医学 | 667篇 |
口腔科学 | 143篇 |
临床医学 | 350篇 |
内科学 | 1553篇 |
皮肤病学 | 61篇 |
神经病学 | 354篇 |
特种医学 | 279篇 |
外科学 | 946篇 |
综合类 | 35篇 |
预防医学 | 129篇 |
眼科学 | 155篇 |
药学 | 376篇 |
中国医学 | 7篇 |
肿瘤学 | 712篇 |
出版年
2024年 | 6篇 |
2023年 | 60篇 |
2022年 | 139篇 |
2021年 | 242篇 |
2020年 | 92篇 |
2019年 | 146篇 |
2018年 | 199篇 |
2017年 | 165篇 |
2016年 | 190篇 |
2015年 | 188篇 |
2014年 | 220篇 |
2013年 | 266篇 |
2012年 | 420篇 |
2011年 | 501篇 |
2010年 | 245篇 |
2009年 | 199篇 |
2008年 | 365篇 |
2007年 | 365篇 |
2006年 | 363篇 |
2005年 | 338篇 |
2004年 | 311篇 |
2003年 | 270篇 |
2002年 | 285篇 |
2001年 | 54篇 |
2000年 | 31篇 |
1999年 | 35篇 |
1998年 | 38篇 |
1997年 | 35篇 |
1996年 | 36篇 |
1995年 | 20篇 |
1994年 | 24篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 12篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有5957条查询结果,搜索用时 15 毫秒
21.
22.
Sensitive and rapid detection of herpes simplex virus and varicella-zoster virus DNA by loop-mediated isothermal amplification 总被引:5,自引:0,他引:5
Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method in which reagents react rapidly and efficiently, with a high specificity, under isothermal conditions. We used a LAMP assay for the detection of herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and varicella-zoster virus (VZV). The virus specificities of primers were confirmed by using 50 HSV-1, 50 HSV-2, and 8 VZV strains. The assay was performed for 45 min at 65 degrees C. The LAMP assay had a 10-fold higher sensitivity than a PCR assay. An analysis of nucleotide sequence variations in the target and primer regions used for the LAMP assay indicated that 3 of 50 HSV-1 strains had single nucleotide polymorphisms. No HSV-2 or VZV strains had nucleotide polymorphisms. Regardless of the sequence variation, there were no differences in sensitivity with the HSV-1-specific LAMP assay. To evaluate the application of the LAMP assay for clinical diagnosis, we tested clinical samples from 40 genital herpes patients and 20 ocular herpes patients. With the LAMP assay, 41 samples with DNA extraction and 26 direct samples without DNA extraction were identified as positive for HSV-1 or HSV-2, although 37 samples with DNA extraction and just one without DNA extraction were positive by a PCR assay. Thus, the LAMP assay was less influenced than the PCR assay by the presence of inhibitory substances in clinical samples. These observations indicate that the LAMP assay is very useful for the diagnosis of HSV-1, HSV-2, and VZV infections. 相似文献
23.
Imai K Zhu Y Revy P Morio T Mizutani S Fischer A Nonoyama S Durandy A 《Clinical immunology (Orlando, Fla.)》2005,115(3):277-285
Autosomal recessive form of hyper-IgM syndrome type 2 (AR-HIGM2) is secondary to mutations affecting both alleles of AICDA gene encoding activation-induced cytidine deaminase, characterized by defects of immunoglobulin class switch recombination (CSR) and somatic hypermutation (SHM) in most of the patients. We herein report the immunological phenotype of seven patients carrying a single heterozygous R190X mutation in AICDA. Variable defect in in vivo CSR inherited as an autosomal dominant (AD) trait strongly suggests that this heterozygous AICDA mutation causes HIGM (AD-HIGM2). In AD-HIGM2 B cells, CSR was consistently found impaired in vitro. However, in contrast to AR-HIGM2, the CSR-induced double-stranded DNA breaks in the switch region of IgM heavy chain gene were detected. The SHM frequency in V regions of IgM heavy chain gene in B cells was normal in all (but one patient). The characteristics of the AD-HIGM2 phenotype indicate that the AID C-terminal region may be involved in DNA repair machinery required for CSR. 相似文献
24.
Suppression of development of diabetes in NOD mice by lactate dehydrogenase virus infection 总被引:1,自引:0,他引:1
Izumi Takei Yoshiaki Asaba Tomohiro Kasatani Taro Maruyama Kenji Watanabe Tatsuo Yanagawa Takao Saruta Toshiharu Ishii 《Journal of autoimmunity》1992,5(6):665-673
It has been reported that lactate dehydrogenase virus (LDV) selectively infects a subpopulation of macrophages, thereby affecting the immune system. We studied the effects of LDV infection on the development of diabetes in non-obese diabetic (NOD) mice. Five-week-old female NOD mice were infected with LDV (10(8) ID50/mouse) and observed until 23 weeks of age. None of the 21-LDV-infected mice developed diabetes, whereas 10/14 (71.4%) uninfected mice did. Although the subpopulations of T cells and the percentage of Mac1-positive cells in the NOD murine spleen and the number of harvested peritoneal macrophages were unaffected by LDV infection, the proportions of Ia-positive peritoneal macrophages were significantly decreased in LDV-infected compared with uninfected mice (1.1 +/- 0.2%, 6.5 +/- 2.9%; P < 0.01). In LDV-infected NOD mice, insulitis of the same grade as that seen in uninfected NOD mice was observed. In another experiment, 3, 5, 10 or 16-week-old female NOD mice were infected with LDV. None of the mice infected with LDV at 3, 5 or 10 weeks of age developed diabetes and only one of six infected at 16 weeks of age did. These findings indicate that LDV infection suppresses the development of diabetes in female NOD mice by reducing the capacity of Ia-positive macrophages, and suggest that the development of human type 1 diabetes may be suppressed by certain viral infections. 相似文献
25.
26.
Tomohiro Mizumoto Toshio Masuda Toshinobu Higashimura 《Macromolecular chemistry and physics.》1995,196(5):1769-1778
Polymerization of phenylacetylenes (PAs) having various ortho-substituents were examined by using MoOCl4—n-Bu4Sn—EtOH (mole ratio 1:1:1) as catalyst. Phenylacetylenes with no or sterically small ortho-substituents did not polymerize in a living fashion. On the other hand, in the polymerization of phenylacetylenes having medium-sized substituents (e.g., CH3, Cl, Br, and iPr), the number-average molecular weights Mn of polymers increased in direct proportion to monomer consumption, while the polydispersity ratios were 1,2– 1,3, which is in favor of living polymerization. Further, monomers having bulky ortho-groups (CF3 and Me3Ge) exhibited excellent living nature with small polydispersity ratios of ≈ 1,1. Thus, it is concluded that not the electronic but the steric effect of the ortho-substituent is important to achieve living polymerization. 相似文献
27.
28.
Regulation of B cell fates by BCR signaling components 总被引:5,自引:0,他引:5
Kurosaki T 《Current opinion in immunology》2002,14(3):341-347
Recent results obtained in mice harboring cytoplasmic mutations of Igalpha and/or Igbeta have reinforced the concept that the strength of BCR signaling is important for ensuring appropriate developmental outcomes as well as antigen-specific responses. To establish the optimal signaling intensity and duration, the BCR utilizes positive and negative regulatory molecules. Studies are beginning to reveal how these molecules maintain immunological homeostasis and tolerance. 相似文献
29.
30.
A common approach to the analysis of gene expression data is to define clusters of genes that have similar expression. A critical step in cluster analysis is the determination of similarity between the expression levels of two genes. We introduce a neural network-based similarity index as a non-linear similarity index and compare the results with other proximity measures for Saccharomyces cerevisiae gene expression data. We show that the clusters obtained using Euclidean distance, correlation coefficients, and mutual information were not significantly different. The clusters formed with the neural network-based index were more in agreement with those defined by functional categories and common regulatory motifs. 相似文献