全文获取类型
收费全文 | 31082篇 |
免费 | 2939篇 |
国内免费 | 1434篇 |
专业分类
耳鼻咽喉 | 149篇 |
儿科学 | 835篇 |
妇产科学 | 1058篇 |
基础医学 | 7883篇 |
口腔科学 | 556篇 |
临床医学 | 2386篇 |
内科学 | 5228篇 |
皮肤病学 | 451篇 |
神经病学 | 2311篇 |
特种医学 | 406篇 |
外国民族医学 | 6篇 |
外科学 | 1513篇 |
综合类 | 4254篇 |
现状与发展 | 8篇 |
一般理论 | 7篇 |
预防医学 | 2306篇 |
眼科学 | 455篇 |
药学 | 2298篇 |
5篇 | |
中国医学 | 602篇 |
肿瘤学 | 2738篇 |
出版年
2024年 | 60篇 |
2023年 | 405篇 |
2022年 | 725篇 |
2021年 | 951篇 |
2020年 | 1009篇 |
2019年 | 1024篇 |
2018年 | 1017篇 |
2017年 | 1064篇 |
2016年 | 1218篇 |
2015年 | 1372篇 |
2014年 | 1858篇 |
2013年 | 2285篇 |
2012年 | 1877篇 |
2011年 | 2146篇 |
2010年 | 1791篇 |
2009年 | 1780篇 |
2008年 | 1848篇 |
2007年 | 1804篇 |
2006年 | 1768篇 |
2005年 | 1393篇 |
2004年 | 1272篇 |
2003年 | 1041篇 |
2002年 | 904篇 |
2001年 | 763篇 |
2000年 | 567篇 |
1999年 | 484篇 |
1998年 | 405篇 |
1997年 | 387篇 |
1996年 | 311篇 |
1995年 | 291篇 |
1994年 | 201篇 |
1993年 | 155篇 |
1992年 | 165篇 |
1991年 | 141篇 |
1990年 | 117篇 |
1989年 | 115篇 |
1988年 | 83篇 |
1987年 | 68篇 |
1986年 | 91篇 |
1985年 | 94篇 |
1984年 | 66篇 |
1983年 | 54篇 |
1982年 | 53篇 |
1981年 | 56篇 |
1980年 | 58篇 |
1979年 | 45篇 |
1978年 | 24篇 |
1976年 | 23篇 |
1973年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
雌激素及其受体对心血管系统保护作用实验研究进展 总被引:8,自引:0,他引:8
雌激素对心血管系统具有重要的保护作用。雌激素及其受体主要通过调节血管舒张功能、抑制血管平滑肌细胞增殖和迁移以及影响肾素 -血管紧张素等介导这一保护作用。但临床上雌激素替代治疗尚未得到肯定 ,需进一步研究 相似文献
92.
Terry R. McGuire 《Behavior genetics》1992,22(4):453-467
Chromosome analysis has been widely used as a first step in eclucidating the genetic architecture of several behaviors ofDrosophila melanogaster. These chromosome studies have generally used incomplete designs or fairly simple statistical analyses. Here I reanalyze two data sets on geotaxis from Pyle (1978) and Ksander (1966) using a biometrical genetic design. Results from the biometrical genetic reanalysis suggest that individual differences in geotaxis might be due to genes on all three major chromosomes which show extensive epistatic interactions. 相似文献
93.
94.
J. M. Ladero R. Arroyo C. De Andrés F. J. Jiménez-Jiménez J. A. Molina E. Varela de Seijas S. Giménez-Roldán J. Benítez 《Acta neurologica Scandinavica》1994,89(2):102-104
To elucidate whether any relationship exists between genetic polymorphic acetylation and the risk for multiple sclerosis (MS), we determined this polymorphism, using sulphamethazine, in 71 patients with definite MS and in 268 age-matched controls. Thirty-seven patients (52.1%) and 151 controls (56.3%) were classified as slow acetylators (not significant difference). No relation was found between acetylator polymorphism and age at onset of disease in MS patient's group. Our results do not support the existence of any relationship between acetylator polymorphism and the risk for MS. 相似文献
95.
No evidence for association between the −112G/A polymorphism of UGRP1 and childhood atopic asthma 总被引:1,自引:0,他引:1
Z. Jian J. Nakayama E. Noguchi M. Shibasaki† T. Arinami 《Clinical and experimental allergy》2003,33(7):902-904
BACKGROUND: Susceptibility to asthma is known to involve genetic factors. Genome-wide screens have indicated that the chromosome 5q31-q34 region is linked to and/or associated with asthma. A new gene, named UGRP1 and reported by Niimi et al., encodes uteroglobin-related protein and is expressed in the lung and trachea. Niimi et al. showed the -112G/A polymorphism of the UGRP1 gene to be associated with asthma in a case-control study. OBJECTIVE: The objective of the present study was to replicate this association and confirm the possible role of the UGRP1-112G/A polymorphism in the aetiology of childhood asthma in a Japanese population. METHODS AND RESULTS: We conducted a transmission disequilibrium test (TDT) in 131 families identified through paediatric patients being treated for asthma. A case-control study was also carried out by comparing the probands and 137 unrelated non-atopic non-asthmatic Japanese children and 211 unrelated healthy Japanese adults. The -112G/A polymorphism was genotyped by the PCR-RFLP method. The TDT revealed that the -112A allele was not preferentially transmitted to asthma-affected children (P=0.85). Neither the presence of at least one A allele in an individual's genotype (sum of the G/A and A/A genotypes) nor the -112A allele was more prevalent among the asthma subjects than among the control subjects. CONCLUSION: Our findings indicate that the UGRP1-112G/A polymorphism does not play a substantial role in genetic predisposition to childhood asthma in this Japanese population. 相似文献
96.
Yao nationality is one of the minority nationalities living mainly in South China (Guangxi Province). The purpose of this
study was to provide data of MHC classI and GLO in Chinese Yao nationality and the different genetic background of Yao and Han nationality, the latter representing
the major nationality in China. The genetic polymorphism of MHC classI and GLO in Chinese Yao nationality was determined. Previously the Japanese were considered to have the lowest C*2C frequencies (0.9386), but now we ascertained that the Yao have the lowest C2*C frequencies (0.9336). The data concerning
gene frequencies of Yao are presented. They were also compared with the available data of Han. 相似文献
97.
98.
Intraperitoneal infection with Salmonella abortusovis is partially controlled by a gene closely linked with the Ity gene. 下载免费PDF全文
I P Oswald F Lantier R Moutier M F Bertrand E Skamene 《Clinical and experimental immunology》1992,87(3):373-378
The aim of the present study was to determine whether the Ity gene, which controls the resistance to S. typhimurium infection in mice, also governs the resistance to S. abortusovis, a serotype specific for goat and sheep. During either i.v. or i.p. infection, BALB/c mice (Itys) were not able to control the growth of S. abortusovis and eventually died from infection. In contrast CBA (Ityr) or (C.CB)F1 (Ityr/s) mice were able to control the growth of these bacteria. Using congenic C.D2 Ityr mice, we found that the gene controlling resistance to S. abortusovis was tightly linked to the Ity gene on chromosome 1. Furthermore, in the spleen and the liver of backcross BALB/c x (CBA x BALB/c) mice, the S. abortusovis resistance phenotype cosegregated with the two alleles of the Len-1 gene, a gene tightly linked to the Ity gene. By contrast, in these backcross mice, the level of infection of the peritoneal cavity, the site of inoculation, did not correlated with the Len-1 phenotype of the animal. These results provide evidence that after i.p. inoculation the control of S. abortusovis growth in the spleen and the liver is controlled by the Ity gene, but also suggest that additional gene(s) regulate the number of bacteria at the site of inoculation. 相似文献
99.
J. C. W. Mak H. C. M. Leung S. P. Ho F. W. S. Ko A. H. K. Cheung M. S. M. Ip M. M. W. Chan-Yeung 《Clinical and experimental allergy》2006,36(4):440-447
BACKGROUND: Reactive oxygen species may contribute to the pathogenesis of asthma. Functional genetic polymorphisms of antioxidant enzymes, superoxide dismutase (SOD) and catalase are good candidates for asthma susceptibility. OBJECTIVE: To investigate the association of the manganese-containing form of SOD (MnSOD) gene at amino acid position 16 (Val16Ala) and catalase gene in the promoter at A-21T and C-262T polymorphisms and asthma in a Hong Kong Chinese population. METHODS: The association study was conducted in a case-control design in asthma patients (n=251) and healthy controls (n=316) by genotyping. The functional significance was assessed by determining erythrocyte SOD and catalase activity. RESULTS: The Val allele of MnSOD at Val16Ala and the A allele of catalase gene at A-21T were not different between patients and controls, while the C allele of catalase gene at C-262T was found to be significantly different between patients and controls (P=0.033). The less frequent variant of catalase gene (-262T) was found to be protective from the development of asthma in a Hong Kong Chinese non-smoking population (adjusted odds ratio=0.35, 0.15-0.85; P=0.017). Asthma patients had elevated erythrocyte SOD and catalase activities in comparison with healthy controls (P<0.01). However, their activities were not associated with different genotypes within healthy controls or asthma patients. CONCLUSION: This is the first report showing that SOD and catalase functional activities are not associated with their respective genetic polymorphisms but related to the presence of asthma in a Hong Kong Chinese population. 相似文献
100.
TLR4 Asp299Gly、Thr399Ile基因多态性对变应性哮喘的发病及IgE水平的影响 总被引:3,自引:0,他引:3
目的 探讨TLR4 (toll likereceptor 4 )Asp2 99Gly、Thr399Ile基因多态性对变应性哮喘的发病和血浆IgE水平的影响。方法 利用聚合酶链反应 限制性片段长度多态性分析技术 (PCR RFLP) ,对 1 97例变应性哮喘患者和 1 5 6例健康人进行TLR4的Asp2 99Gly、Thr399Ile两位点的基因型检测。同时利用免疫发光法检测血浆IgE的水平。结果 1 97例变应性哮喘患者TLR4基因Asp2 99Gly位点Asp Asp、Asp Gly和Gly Gly的基因型频率为 0 .81 7、0 .1 4 7和 0 .0 36 ,与正常对照组相比差异无统计学意义 (χ2 =0 .0 32 ,P =0 .984 ) ;但变应性哮喘患者Gly Gly、Asp Gly基因型血浆总IgE对数值 ( x±s:2 .6 1 5± 0 .6 0 0 1 ,n =36 )与Asp Asp基因型血浆总IgE对数值 ( x±s:2 .2 4 0± 0 .6 894 ,n =1 6 1 )相比较高 ,差异有统计学意义 (P =0 .0 0 2 )。TLR4基因Thr399Ile位点Thr Thr、Thr Ile和Ile Ile的基因型频率为 0 .970、0 .0 2 0和 0 .0 1 0 ,与正常对照组相比差异无统计学意义 (χ2 =0 .6 2 0 ,P =0 .733) ;变应性哮喘患者Ile Ile、Thr Ile基因型血浆总IgE对数值 ( x±s:2 .4 1 7± 0 .4 4 2 3,n =6 )与Thr Thr基因型血浆总IgE对数值 ( x±s:2 .30 5± 0 .6 94 9,n =1 91 )相比差异无统计学意义 (P =0 .5 71 )。 相似文献