全文获取类型
收费全文 | 1085篇 |
免费 | 102篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 74篇 |
妇产科学 | 31篇 |
基础医学 | 98篇 |
口腔科学 | 36篇 |
临床医学 | 171篇 |
内科学 | 226篇 |
皮肤病学 | 27篇 |
神经病学 | 88篇 |
特种医学 | 156篇 |
外科学 | 74篇 |
综合类 | 25篇 |
预防医学 | 88篇 |
眼科学 | 13篇 |
药学 | 58篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 51篇 |
出版年
2023年 | 2篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 21篇 |
2017年 | 24篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 39篇 |
2013年 | 47篇 |
2012年 | 23篇 |
2011年 | 40篇 |
2010年 | 46篇 |
2009年 | 68篇 |
2008年 | 30篇 |
2007年 | 50篇 |
2006年 | 25篇 |
2005年 | 26篇 |
2004年 | 12篇 |
2003年 | 19篇 |
2002年 | 12篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 25篇 |
1998年 | 74篇 |
1997年 | 82篇 |
1996年 | 59篇 |
1995年 | 52篇 |
1994年 | 37篇 |
1993年 | 43篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 28篇 |
1988年 | 25篇 |
1987年 | 31篇 |
1986年 | 17篇 |
1985年 | 18篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1930年 | 1篇 |
排序方式: 共有1233条查询结果,搜索用时 15 毫秒
21.
22.
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
23.
Non-invasive detection of fecal protein kinase C betaII and zeta messenger RNA: putative biomarkers for colon cancer 总被引:2,自引:0,他引:2
Davidson LA; Aymond CM; Jiang YH; Turner ND; Lupton JR; Chapkin RS 《Carcinogenesis》1998,19(2):253-257
We have developed a non-invasive method utilizing feces, containing
sloughed colonocytes, as a sensitive technique for detecting diagnostic
colonic biomarkers. In this study, we used the rat colon carcinogenesis
model to determine if changes in fecal protein kinase C (PKC) expression
have predictive value in monitoring the neoplastic process. Weanling rats
were injected with saline or azoxymethane (AOM) and 36 weeks later fecal
samples and mucosa were collected, poly A+ RNA isolated, and quantitative
RT-PCR performed using primers to PKC betaII and zeta. Fecal PKC betaII and
zeta mRNA levels were altered by the presence of a tumor, with
tumor-bearing animals having a 3-fold higher (P < 0.05) PKC betaII
expression as compared with animals without tumors. In addition,
AOM-injection increased mucosal PKC betaII mRNA expression compared with
saline controls. No effect of tumor incidence on mucosal PKC betaII
expression was observed. In contrast, fecal PKC zeta expression was
2.5-fold lower (P < 0.05) in animals injected with azoxymethane versus
saline. Since tumor incidence exerts a reciprocal effect on fecal PKC
betaII and zeta mRNA expression, data were also expressed as the ratio
between PKC betaII and zeta. The isozyme ratio was strongly related to
tumor incidence, i.e. ratio for animals with tumors was 2.18 +/- 1.25,
animals without tumors was 0.50 +/- 0.16, P = 0.025. We demonstrate that
the expression of fecal PKC betaII and zeta may serve as a noninvasive
marker for development of colon tumors. A sensitive technique for the
detection of colon cancer is of importance since early diagnosis can
substantially reduce mortality.
相似文献
24.
Perspectives on colorectal cancer screening: a focus group study 总被引:3,自引:0,他引:3
Vivek Goel MD MSc FRCPC Ross Gray PhD Pam Chart MD CM Marg Fitch RN PhD Fred Saibil MD FRCPC Yola Zdanowicz MA 《Health expectations》2004,7(1):51-60
Objective To assess attitudes and acceptability of Ontario consumers and doctors towards colorectal screening with faecal occult blood testing (FOBT) and colonoscopy. Design, setting and participants Focus groups with gender‐specific samples of the population, high‐risk gastroenterology patients and family doctors. Method Semi‐structured interview guides used by facilitator to lead groups through knowledge of risk factors and prevention of colorectal cancer, the screening modalities, requirements for implementing screening programmes, barriers to screening and preferences towards screening. Main findings There were low levels of knowledge about colorectal cancer and its prevention in the general population. FOBT was an acceptable screening modality, but considerable education about its use and benefits would be necessary to implement a screening programme. Colonoscopy was not perceived to be a good choice for a primary screen in the general population. The high‐risk group supported use of FOBT in the general population and emphasized the need for education. The doctors were more reluctant about screening, requesting clear guidelines. They also identified the time and resources that would be required if a screening programme were initiated. Conclusion While colorectal screening is acceptable in this sample, information and decision aids are required to enable consumers and providers to make effective decisions. Implementation of colorectal screening programmes requires substantial educational efforts for both consumers and doctors. 相似文献
25.
26.
氯地滴眼液的含量测定 总被引:4,自引:0,他引:4
目的:采用HPLC法测定氯地滴眼液中氯霉素和地塞米松磷酸钠的含量。方法:色谱分析条件:ODS柱作分析柱,流动相为甲醇/水体系,0 ̄8min使用40%甲醇,8 ̄16min使用60%甲醇,流速1ml/min,0 ̄9min240nm紫外检测,:二组分分离良好。各组各组性关系良好,平均回收率氯霉素99.8%(RSD=1.2%,n=5),地塞米松磷酸钠99.4%(RSD=0.7%,n=5),结论:该法用于氯 相似文献
27.
28.
Purpose.?To explore disability in women with fibromyalgia with a focus on their work situation.Method.?Review of literature on work status of women with fibromyalgia.Results.?Major differences exist between studies in reported disability and in the percentages of women working. Limitations caused by pain, fatigue, decreased muscle strength, and endurance influence work capacity. However, 34?–?77% of the women work. Individual adjustments in the work situation are reported. When the women find a level that matches their ability, they continue to work and find satisfaction in their work role. Many factors besides degree of impairment or disability influence whether clients with longstanding pain can remain in their work role or return to work after sickness leave.Conclusion.?The total life situation, other commitments, type of work tasks, the ability to influence the work situation, and the physical and psychosocial work environment are important factors in determining whether a person can remain in a work role. More knowledge is needed about how to adjust work conditions for people with partial work ability to the benefit of society and the individual. 相似文献
29.
A 45-year-old male patient with Ph-negative chronic myeloid leukemia (CML) had rearranged bcr-3' and bcr-5' gene regions in Southern blot studies when leukemia was diagnosed. During development of terminal blast crisis, successive blood samples showed a progressive decrease in the amount of germline bcr DNA and its complete loss by full blast crisis. There were also increased amounts of rearranged bcr DNA consistent with acquired homozygosity. A similar result was obtained with an IgV lambda probe and indicated homozygosity of a significant part of chromosome 22. The bcr-abl gene complex behaves as a somatic dominant in CML, and we suggest that its acquired homozygosity is a mechanism of bcr-abl amplification similar to duplication of the Ph chromosome commonly found in the blast crisis of CML. 相似文献
30.