全文获取类型
收费全文 | 503篇 |
免费 | 33篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 31篇 |
妇产科学 | 4篇 |
基础医学 | 42篇 |
口腔科学 | 8篇 |
临床医学 | 53篇 |
内科学 | 94篇 |
皮肤病学 | 6篇 |
神经病学 | 51篇 |
特种医学 | 50篇 |
外科学 | 68篇 |
综合类 | 42篇 |
预防医学 | 26篇 |
眼科学 | 7篇 |
药学 | 31篇 |
肿瘤学 | 33篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 23篇 |
2012年 | 16篇 |
2011年 | 23篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 27篇 |
1997年 | 24篇 |
1996年 | 20篇 |
1995年 | 10篇 |
1994年 | 21篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有562条查询结果,搜索用时 15 毫秒
1.
2.
3.
CG Teo 《Oral diseases》2002,8(S2):88-90
Oral hairy leukoplakia (OHL) and Kaposi's sarcoma (KS) are commonly encountered in the HIV-infected patient. A unique feature of OHL is non-cytolytic high level of replication of Epstein–Barr virus (EBV) in the glossal epithelium. The expression of viral-encoded anti-apoptotic proteins concomitant to replicative proteins probably underlies this phenomenon. The question of whether OHL arises from activation of EBV latent in the tongue, or from superinfection by endogenous EBV shed via non-glossal sites or by exogenous EBV remains unresolved. Human herpesvirus 8 (HHV8) is now seen as necessary but not sufficient cause of KS. Expression of HHV8-encoded oncogenic proteins in endothelial cells probably explains the aberrant proliferation of these cells in KS lesions. Studies into why KS is so commonly observed at the palate in HIV-infected patients may provide important clues to its pathogenesis. 相似文献
4.
5.
W W Loney B J Kudchodkar S Weis M B Clearfield J Shores A G Lacko 《American journal of therapeutics》1997,4(9-10):301-309
Subjects with high-density lipoprotein cholesterol (HDL-C) values of less than 47 mg/dL (mean 35.6 +/- 5.5 mg/dL) were selected for this study to examine relationships between plasma lipids, lipoprotein components, and the outcome of gemfibrozil therapy. Changes in plasma lipoprotein subfractions were determined to better understand the previously observed variability of the responses in both HDL-C and triglycerides to gemfibrozil. Based on the data collected, an attempt was made to identify pretreatment lipid parameters that may be predictive regarding the efficacy of gemfibrozil therapy. Serum samples were analyzed at the outset and after the conclusion of 12 weeks of gemfibrozil therapy. Because the HDL-C response to therapy was highly variable, the data from patients were separated into two groups, responders (>20% increase in HDL-C) and nonresponders (<20% increase in HDL-C). The lipid components of lipoprotein subfractions were evaluated using multiple regression analysis yielding predictive models that show the relationship between specific lipoprotein subfractions and the percentage change in HDL-C and posttreatment triglyceride levels. Group classification was then predicted with 78% accuracy using specific lipoprotein subfractions to estimate an individual's percentage change in HDL-C. The major difference between the responder and nonresponder groups was their respective correlations between triglyceride-lowering and changes in HDL-C. In the responder group, there was a significant correlation between the changes in HDL-C and the lowering of triglycerides (r = 0.61, p = 0.03), whereas the nonresponder group showed no such correlation (r = 0.17, p = 0.52). The predictive model also proved to be highly accurate in forecasting the effectiveness of the triglyceride-lowering action of gemfibrozil in this group of patients. 相似文献
6.
7.
The steroidogenic enzymes, P450 aromatase (P450arom) and P450 17alpha-hydroxylase (P45017alpha), were precisely located within the healthy porcine follicle by immunohistochemistry. Enzyme distribution was examined throughout follicular development during natural oestrous cycles (n = 14 gilts) and was compared with steroid production by healthy whole and theca-only follicles. All follicles 2 mm or more in diameter were either fixed for immunohistochemistry (n = 380 of which 197 were assessed as healthy) or incubated as whole (n = 110) or theca-only (n = 110) follicles to measure steroidogenesis. P45017alpha was confined to the theca layer. The number of positive cells and staining intensity increased with follicle size. P450-arom was consistently detected in the granulosa layer of follicles measuring 6 mm or more in diameter and those cells furthest from the antrum were most strongly stained. P450arom was also detected in the theca layer of these large follicles. Whole and theca-only follicles produced oestradiol and androstenedione, and the levels of both hormones increased with follicle size (P<0.001). Whole follicles produced more oestradiol (P<0.001), but less androstenedione (P = 0.01) than theca-only follicles of the same size. Although granulosa cells contained P450arom and synthesized oestradiol, only theca cells contained P45017alpha. Theca cells therefore provided granulosa cells with androgen substrate. In addition, theca cells possessed P450arom, making them capable of independent oestradiol production, which may be required to trigger the LH surge. This study confirms the vital role of theca cells in follicular steroidogenesis in the pig. 相似文献
8.
Noll DR Shores J Bryman PN Masterson EV 《The Journal of the American Osteopathic Association》1999,99(3):143-6, 151-2
To evaluate the benefit of osteopathic manipulative treatment in the elderly with pneumonia, the authors recruited 21 individuals older than 60 years who were hospitalized with acute pneumonia. Eleven patients were randomly assigned to the treatment group and ten to the control group. The treatment group received specific osteopathic manipulative treatment for somatic dysfunction and a standardized treatment protocol. Both groups received conventional therapy, and the attending physician was blind to group assignments. No significant difference existed between groups for age, sex, or severity of illness. Although the mean duration of leukocytosis, intravenous antibiotic treatment, and length of stay were shorter for the treatment group, these measures did not reach statistical significance. However, the mean duration of oral antibiotic use did reach statistical significance at 3.1 days for the treatment group and 0.8 day for the control group. Osteopathic manipulative treatment may reduce antibiotic use and length of stay; however, a larger study is needed to clarify this outcome. 相似文献
9.
Arif JM; Gairola CG; Glauert HP; Kelloff GJ; Lubet RA; Gupta RC 《Carcinogenesis》1998,19(8):1515-1517
The present study investigated the effects of dietary oltipraz on cigarette
smoke-related lipophilic DNA adduct formation. Female Sprague- Dawley rats
were exposed daily to sidestream cigarette smoke in a whole- body exposure
chamber 6 h/day for 4 consecutive weeks. One group of rats was maintained
on control diet while another group received the same diet supplemented
with either a low (167 p.p.m.) or high (500 p.p.m.) dose of oltipraz,
starting 1 week prior to initiation of smoke exposure until the end of the
experiment. Analysis of lipophilic DNA adducts by the nuclease P1-mediated
32P-post-labeling showed up to five smoke-related adducts. Adduct no. 5
predominated in both the lung and the heart while adduct nos 3 and 2
predominated in the trachea and bladder, respectively. Quantitative
analysis revealed that the total adduct level was the highest in lungs
(270+/-68 adducts/10(10) nucleotides), followed by trachea (196+/-48
adducts/10(10) nucleotides), heart (141+/-22 adducts/10(10) nucleotides)
and bladder (85+/-16 adducts/10(10) nucleotides). High dose oltipraz
treatment reduced the adduct levels in lungs and bladder by >60%, while
the reduction in lungs in the low-dose group was approximately 35%. In
trachea, the effect of low and high dietary oltipraz on smoke DNA adduction
was equivocal, while smoke-related DNA adducts in the heart were minimally
inhibited by high-dose oltipraz. In a repeat experiment that employed a
3-fold lower dose of cigarette smoke, oltipraz (500 p.p.m.) was found to
inhibit the formation of DNA adducts in rat lungs and trachea by 80 and
65%, respectively. These data clearly demonstrate a high efficacy of
oltipraz in inhibiting the formation of cigarette smoke-induced DNA adducts
in the target tissues.
相似文献
10.
Mutation of the p53 tumor suppressor gene in spontaneously occurring osteosarcomas of the dog 总被引:8,自引:0,他引:8
Inactivation of the p53 tumor suppressor gene has been implicated in the
pathogenesis of numerous human cancers, including osteosarcomas.
Appendicular osteosarcomas of the dog appear to be a good model for their
human equivalent with regard to biologic behavior, epidemiology and
histopathology. We individually screened exons 5-8 of the p53 gene for
mutations in 15 canine appendicular osteosarcomas using 'Cold' SSCP to
compare the role of this gene in human and canine osteosarcoma
tumorigenesis. Seven of the tumors (47%) exhibited point mutations, with
one tumor possessing two mutations within different exons. Of these, seven
were missense mutations and the eighth was a 'silent' mutation potentially
affecting the exon 6-7 splicing region. Five of the missense mutations were
located in highly conserved regions IV and V, while another corresponded
with the highly conserved codon 220 mutational hotspot located outside the
conserved domains. The locations and types of mutations were nearly
identical to those reported in human cancer. These findings provide strong
evidence of the involvement of p53 mutations in the development of canine
appendicular osteosarcomas. Canine osteosarcomas appear to be a promising
model for their human equivalent on a clinical, pathologic, and molecular
level.
相似文献