全文获取类型
收费全文 | 6229篇 |
免费 | 392篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 84篇 |
儿科学 | 206篇 |
妇产科学 | 179篇 |
基础医学 | 879篇 |
口腔科学 | 182篇 |
临床医学 | 601篇 |
内科学 | 1336篇 |
皮肤病学 | 84篇 |
神经病学 | 742篇 |
特种医学 | 523篇 |
外国民族医学 | 1篇 |
外科学 | 779篇 |
综合类 | 95篇 |
一般理论 | 3篇 |
预防医学 | 308篇 |
眼科学 | 71篇 |
药学 | 261篇 |
中国医学 | 1篇 |
肿瘤学 | 365篇 |
出版年
2021年 | 77篇 |
2019年 | 67篇 |
2018年 | 98篇 |
2017年 | 77篇 |
2016年 | 100篇 |
2015年 | 97篇 |
2014年 | 131篇 |
2013年 | 184篇 |
2012年 | 232篇 |
2011年 | 219篇 |
2010年 | 176篇 |
2009年 | 148篇 |
2008年 | 222篇 |
2007年 | 262篇 |
2006年 | 188篇 |
2005年 | 229篇 |
2004年 | 173篇 |
2003年 | 205篇 |
2002年 | 188篇 |
2001年 | 163篇 |
2000年 | 185篇 |
1999年 | 163篇 |
1998年 | 123篇 |
1997年 | 118篇 |
1996年 | 104篇 |
1995年 | 101篇 |
1994年 | 64篇 |
1993年 | 77篇 |
1992年 | 148篇 |
1991年 | 157篇 |
1990年 | 127篇 |
1989年 | 152篇 |
1988年 | 117篇 |
1987年 | 128篇 |
1986年 | 117篇 |
1985年 | 133篇 |
1984年 | 85篇 |
1983年 | 73篇 |
1982年 | 86篇 |
1981年 | 61篇 |
1980年 | 61篇 |
1979年 | 66篇 |
1978年 | 51篇 |
1977年 | 70篇 |
1976年 | 51篇 |
1975年 | 74篇 |
1974年 | 44篇 |
1973年 | 49篇 |
1972年 | 49篇 |
1967年 | 43篇 |
排序方式: 共有6700条查询结果,搜索用时 953 毫秒
51.
The ability of herpes simplex virus type 1 to productively infect human T-cell subpopulations was examined. Unstimulated helper/inducer (T4+) and cytotoxic/suppressor (T8+) lymphocytes limited herpes simplex virus replication as effectively as unseparated peripheral blood T cells (T3+). Phytohemagglutinin stimulation before infection resulted in equivalently productive herpes simplex virus infections in the three cell fractions. 相似文献
52.
Analysis of orthologous gene expression between human pulmonary adenocarcinoma and a carcinogen-induced murine model
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stearman RS Dwyer-Nield L Zerbe L Blaine SA Chan Z Bunn PA Johnson GL Hirsch FR Merrick DT Franklin WA Baron AE Keith RL Nemenoff RA Malkinson AM Geraci MW 《The American journal of pathology》2005,167(6):1763-1775
Human adenocarcinoma (AC) is the most frequently diagnosed human lung cancer, and its absolute incidence is increasing dramatically. Compared to human lung AC, the A/J mouse-urethane model exhibits similar histological appearance and molecular changes. We examined the gene expression profiles of human and murine lung tissues (normal or AC) and compared the two species' datasets after aligning approximately 7500 orthologous genes. A list of 409 gene classifiers (P value <0.0001), common to both species (joint classifiers), showed significant, positive correlation in expression levels between the two species. A number of previously reported expression changes were recapitulated in both species, such as changes in glycolytic enzymes and cell-cycle proteins. Unexpectedly, joint classifiers in angiogenesis were uniformly down-regulated in tumor tissues. The eicosanoid pathway enzymes prostacyclin synthase (PGIS) and inducible prostaglandin E(2) synthase (PGES) were joint classifiers that showed opposite effects in lung AC (PGIS down-regulated; PGES up-regulated). Finally, tissue microarrays identified the same protein expression pattern for PGIS and PGES in 108 different non-small cell lung cancer biopsies, and the detection of PGIS had statistically significant prognostic value in patient survival. Thus, the A/J mouse-urethane model reflects significant molecular details of human lung AC, and comparison of changes in orthologous gene expression may provide novel insights into lung carcinogenesis. 相似文献
53.
Spinocerebellar ataxia type 7 (SCA7): a neurodegenerative disorder with neuronal intranuclear inclusions 总被引:8,自引:13,他引:8
Holmberg M; Duyckaerts C; Durr A; Cancel G; Gourfinkel-An I; Damier P; Faucheux B; Trottier Y; Hirsch EC; Agid Y; Brice A 《Human molecular genetics》1998,7(5):913-918
Autosomal dominant cerebellar ataxia with progressive macular degeneration
is caused by a CAG/glutamine repeat expansion in the SCA7 gene/protein.
Neuronal intranuclear inclusions were detected in the brain of an early
onset SCA7 case with the 1C2 antibody directed against an expanded
polyglutamine domain. Nuclear inclusions were most frequent in the inferior
olivary complex, a site of severe neuronal loss in SCA7. They were also
observed in other brain regions, including the cerebral cortex, not
considered to be affected in the disease. Using confocal microscopy we
showed that some inclusions were ubiquitinated, but to varying degrees,
ranging from <1% in the cerebral cortex to 60% in the inferior olive. In
addition, we also observed cytoplasmic staining using the 1C2 antibody,
particularly in the supramarginal gyrus, the hippocampus, the thalamus, the
lateral geniculate body and the pontine nuclei. These data confirm that the
presence of intranuclear inclusions in neurons is a common characteristic
of disorders caused by CAG/polyglutamine expansions, but unlike what has
been reported for Huntington's disease, SCA1 and SCA3/MJD, in SCA7 the
inclusions were not restricted to the sites of severe neuronal loss.
相似文献
54.
Herpes simplex virus (HSV) type 1 replicated and persisted in human T, B, and myeloid cell lines with different patterns of viral replication and various effects on cell growth. T cell line CEM supported the replication of HSV for over 400 days without detectable differences in cell growth as compared with uninfected cells. HSV persisted in B cell line NC37 and myeloid cell line K562 for up to 222 and 374 days, respectively, but led to a significant decrease in the number of viable cells by 7 weeks of infection. The average number of cells producing infectious virus was very low in these cell lines (range, 0.5 to 2.7+) compared with a larger proportion of cells exhibiting HSV antigens by immunofluorescence (range, 24 to 58%). In contrast, null cell line LAZ 221 failed to replicate HSV even though the viral infection led to a cessation of cell growth. 相似文献
55.
Application of reflectance spectroscopy to the estimation of uric acid, urea and glucose: an evaluation of the Ames Seralyzer
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
An original approach to the measurement of analytes in clinical chemistry has now become available, in which dry reagent strip technology is linked to measurement by reflectance spectroscopy. The present studies have evaluated the performance of the first of these test systems—for uric acid, urea and glucose, in serum—by comparison with conventional liquid chemistry methods. Satisfactory performance in terms of both precision and accuracy was obtained for all three test systems, the current “state-of-the-art” performance criteria being met; the Seralyzer system proved reliable and easy to use in the hands of trained operators. It should find a place as a “Stat” analyser in the laboratory, in specified wards and in Health Centres. 相似文献
56.
57.
DNA microarray analysis reveals novel gene expression profiles in collagen-induced arthritis 总被引:4,自引:0,他引:4
Thornton S Sowders D Aronow B Witte DP Brunner HI Giannini EH Hirsch R 《Clinical immunology (Orlando, Fla.)》2002,105(2):155-168
Global gene expression was analyzed in early and late collagen-induced arthritis (CIA). Of 8734 cDNAs analyzed, 330 were induced and 55 downregulated greater than twofold in early or late disease. Hierarchical clustering of these 385 cDNAs demonstrated five distinct expression patterns differentiating early from late disease and correlating with histopathologic changes in the paw. Of the 385 cDNAs, 185 are known, characterized genes, the majority of which are not described as playing a role in arthritis. However, several of these genes are involved in pathological processes relating to arthritis, including apoptosis, inflammation, and cellular proliferation. One interesting gene, follistatin-like gene, is highly expressed along the margin of contact between inflammatory synovial pannus and eroding bone, suggesting a role in joint destruction. These results demonstrate that global gene expression profiles distinguish early and late CIA and reveal several genes novel to arthritis the further characterization of which will advance our understanding of arthritis. 相似文献
58.
Influence of co-culture with established human endometrial epithelial and stromal cell lines on sperm movement characteristics 总被引:2,自引:0,他引:2
The effects of co-culture of human spermatozoa with human immortalized
endometrial cells - epithelial or stromal - on sperm movement
characteristics, including hyperactivation, were studied using computer-
assisted sperm analysis (CASA). Epithelial and stromal cell types could be
separated following 8-10 days of culture of endometrial cells originating
from human biopsies. Both cell types were immortalized by the SV 40 large T
antigen. Co-incubation of sperm with epithelial and stromal monolayers
enhanced the rate of hyperactivation: 24.9% (P <0.05) and 17.8% (P =
0.05) versus 9.5% as control, respectively, whereas the majority of
motility parameters remained unchanged. Conditioned media had no effect
upon sperm parameters, including hyperactivation. Co-incubation with either
monolayer was able to maintain sperm motility over a longer period than
incubation in control medium alone. In four patients whose spermatozoa did
not exhibit hyperactivation, co-incubation with epithelial cells, but not
conditioned medium, allowed normal rates of hyperactivation (range: 6.9-
15.6%).
相似文献
59.
60.
Hirsch VM 《AIDS reviews》2004,6(1):40-53
The simian immunodeficiency viruses are a diverse group of viruses that naturally infect a wide range of African primates, including chimpanzees, African green monkeys (AGM) and sooty mangabey monkeys (SM). Although natural infection is widespread in feral populations of AGMs and SMs, this infection does not result in immunodeficiency. However, experimental inoculation of Asian macaque species results in an immunodeficiency syndrome that is remarkably similar in pathogenesis to human AIDS. Thus, SIVsm infection of macaques results in AIDS, and similarly experimental inoculation of pigtailed macaques with at least one SIVagm isolate, SIVIhoest or SIVsun, results in AIDS. The extent of plasma viremia in pathogenic infection is an excellent prognostic indicator of clinical course, with higher viral load being predictive of shorter survival and low viremia being predictive of long-term non-progression. Based upon this paradigm, one would have expected naturally infected animals to exhibit low levels of viremia. In reality, AGMs, SMs, mandrills and chimpanzees infected naturally with their own unique viruses display moderate to high levels of plasma viremia. A significant reduction in CD4+ T-cells in infected versus uninfected SMs suggests that the virus may be cytopathic to some degree. These infected animals still maintain adequate CD4+ T-cells over their entire life in captivity. A distinct characteristic of natural infection is the lack of immunopathology as demonstrated by normal lymph node morphology, lower expression of activation and proliferation markers on CD4+ T-cells, and a generally muted immune response to the virus. Naturally infected SMs and AGMs clearly mount antiviral cellular and humoral immune responses. Therefore, models suggesting immune tolerance to SIV are far too simplistic to explain the lack of disease in these animals. It is probable that a unique balance between T-cell renewal and proliferation and loss through activation-induced apoptosis, and virus-induced cell death has been achieved in SMs and AGMs. The study of the dynamics of T-cell production, proliferation and cell death in asymptomatic natural infection should, therefore, yield insights into the pathogenesis of AIDS. 相似文献