全文获取类型
收费全文 | 7804篇 |
免费 | 522篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 168篇 |
妇产科学 | 105篇 |
基础医学 | 941篇 |
口腔科学 | 113篇 |
临床医学 | 808篇 |
内科学 | 1797篇 |
皮肤病学 | 167篇 |
神经病学 | 523篇 |
特种医学 | 478篇 |
外科学 | 1337篇 |
综合类 | 141篇 |
一般理论 | 3篇 |
预防医学 | 502篇 |
眼科学 | 150篇 |
药学 | 463篇 |
中国医学 | 15篇 |
肿瘤学 | 629篇 |
出版年
2023年 | 64篇 |
2022年 | 105篇 |
2021年 | 218篇 |
2020年 | 93篇 |
2019年 | 180篇 |
2018年 | 217篇 |
2017年 | 148篇 |
2016年 | 173篇 |
2015年 | 213篇 |
2014年 | 304篇 |
2013年 | 415篇 |
2012年 | 553篇 |
2011年 | 522篇 |
2010年 | 348篇 |
2009年 | 314篇 |
2008年 | 439篇 |
2007年 | 480篇 |
2006年 | 416篇 |
2005年 | 436篇 |
2004年 | 369篇 |
2003年 | 332篇 |
2002年 | 300篇 |
2001年 | 136篇 |
2000年 | 106篇 |
1999年 | 96篇 |
1998年 | 134篇 |
1997年 | 120篇 |
1996年 | 109篇 |
1995年 | 72篇 |
1994年 | 77篇 |
1993年 | 69篇 |
1992年 | 63篇 |
1991年 | 40篇 |
1990年 | 49篇 |
1989年 | 72篇 |
1988年 | 78篇 |
1987年 | 63篇 |
1986年 | 50篇 |
1985年 | 45篇 |
1984年 | 33篇 |
1983年 | 24篇 |
1982年 | 32篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1979年 | 24篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 25篇 |
1975年 | 16篇 |
1973年 | 20篇 |
排序方式: 共有8397条查询结果,搜索用时 31 毫秒
51.
Mosaic ring 12p and total anomalous pulmonary venous return 总被引:1,自引:0,他引:1
Harris DL Siu BL Hummel M Harbert K Senft J Sargent L Wenger SL 《American journal of medical genetics. Part A》2004,131(1):91-93
An infant born with total anomalous pulmonary venous return (TAPVR) was found to have an extra chromosome present as a small ring. Spectral karyotyping and FISH analysis identified the material as a duplication involving the short arm of chromosome 12. Previous cases describing a variety of cytogenetic abnormalities that have been associated with TAPVR are reviewed along with prior cases of duplication 12p with their associated findings. We believe ours is the first case to report the occurrence of mosaic ring 12p and its association with TAPVR. 相似文献
52.
Verschuren MC; Blom B; Bogers AJ; Spits H; van Dongen JJ 《International immunology》1998,10(12):1873-1880
Recombination of deltaRec to psiJalpha will delete the TCR delta gene,
which is thought to play an important role in the bifurcation of the TCR
alphabeta versus TCR gammadelta differentiation lineages. We recently
detected a DNA-binding protein in human thymocytes, the so- called PJA-BP,
which recognizes the psiJalpha gene segment and might be one of the factors
involved in the regulation of preferential deltaRec- psiJalpha
rearrangements. We now investigate PJA-BP expression and its correlation
with TCR delta gene deletion in thymocytes. Our electrophoretic mobility
shift assay experiments showed that the PJA-BP is evolutionary conserved in
human, murine and simian thymocytes. Using a large series of human
hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is
thymocyte specific and seems to be restricted to thymocytes committed to
the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte
subpopulations showed that preferential deltaRec-psiJalpha rearrangements
as well as PJA-BP expression can be detected from the immature
CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage
onwards. These experiments indicate that expression of PJA-BP in human
thymocytes starts simultaneously with preferential deltaRec-psiJalpha
rearrangements, which supports our hypothesis that PJA-BP is one of the
factors involved in the preferential recombination of deltaRec to
psiJalpha.
相似文献
53.
Husaini BA Sherkat DE Levine R Bragg R Van CA Emerson JS Mentes CM 《Journal of the National Medical Association》2002,94(2):100-106
This study examines the effectiveness of breast cancer screening education programs on mammography rates among African-American women 40 years of age and over. We conducted two types of educational programs in community settings, primarily in African-American churches. Three-month follow-up interviews were used to determine whether women who participated in programming were more likely to get a mammogram if they had not had a mammogram in the last year. Our results demonstrate that the educational programs significantly increased the likelihood of getting a mammogram when compared to a control group that received no educational programming. Further, we found that the programs were effective for motivating breast cancer screening in housing projects as well as in the churches, and that the effectiveness of the programs remained even when we controlled for socioeconomic status, depression, and age. 相似文献
54.
Bojian Zheng Ming-Liang He King-Ling Wong Ching Tung Lum Leo L M Poon Ying Peng Yi Guan Marie C M Lin Hsiang-Fu Kung 《Journal of interferon & cytokine research》2004,24(7):388-390
We sought to investigate the anti-severe acute respiratory syndrome (SARS)-associated coronavirus (SCoV) activities of type I (alpha and beta) and type II (gamma) interferons (IFN) in vitro. Type I IFNs protected cells from cytopathic effects (CPE) induced by SCoV, and inhibited viral genomic RNA replication in FRhk-4 cells (measured by quantitative RT-PCR) in a dose-dependent manner. Intracellular viral RNA copies were reduced 50% by IFN-alpha at a concentration of 25 U/ml and by IFN-beta at a concentration of 14 U/ml. IFN-gamma had fewer effects on inhibition of viral infection and replication. The type I IFN receptor signaling pathway in host cells is mainly involved in the inhibition of SCoV infection and replication. Type I IFNs could be used as potential agents for anti-SARS treatment. 相似文献
55.
56.
Heterozygous carriers of mutations in the BRCA2 gene have a high risk of developing breast and other cancers. In these individuals, BRCA2 appears to act as a tumour suppressor gene, in that loss of the wild type allele is frequently observed within tumours, leading to loss of BRCA2 function. Because BRCA2 functions in DNA repair via homologous recombination, this leads to genomic instability. However, it is unclear whether loss of the wild type allele is stochastic or if heterozygosity for BRCA2 mutation carries a phenotype that contributes to tumorigenic progression. Here we demonstrate that, in a specific vertebrate cell type, the chicken B cell line DT40, heterozygosity for a BRCA2 mutation has a distinct phenotype. This is characterized by a reduced growth rate, increased cell death, heightened sensitivity to specific DNA damaging agents and reduced RAD51 focus formation after irradiation. Thus in certain cell types, genome instability might be driven directly by heterozygosity for BRCA2 mutation. 相似文献
57.
58.
We prospectively compared a single-tube multiplex polymerase chain reaction (PCR) for detecting alpha-thalassemia with our current approach using 452 blood samples. Initial evaluation of 89 specimens revealed sensitivity and specificity, respectively, for the hemoglobin H inclusion body test (HbH prep) vs PCR for detecting alpha0-thalassemia carriers of 0.79 and 0.96 and for a mean corpuscular volume (MCV) of 82 microm3 (82 fL) or less, 1.0 and 0.45. Detection of all alpha-thalassemia genotypes was significantly lower for HbH prep and MCV (sensitivity and specificity, respectively: HbH prep, 0.48 and 0.96; MCV, 0.87 and 0.47). In a follow-up evaluation of patients with positive HbH prep results or suspected alpha-thalassemia prescreened by low MCV, the sensitivity and specificity, respectively, of HbH prep vs PCR increased to 0.97 and 0.93 for alpha0-thalassemia and 0.83 and 0.92 for any alpha-thalassemia. PCR detected alpha-thalassemia in 37.2% of 298 suspected alpha-thalassemia cases with suggestive indices but negative HbH prep results and no detectable hemoglobinopathy. This multiplex approach was more sensitive than the HbH prep for detecting all alpha-thalassemia genotypes, particularly alpha+-thalassemia; was particularly valuable for identifying carriers of alpha0-thalassemia at risk for offspring with hemoglobin Bart hydropsfetalis, regardless of other diagnosed hemoglobinopathies; and is an ideal adjunct to standard clinical screening protocols for detecting alpha-globin deletions. 相似文献
59.
60.