全文获取类型
收费全文 | 2663篇 |
免费 | 283篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 124篇 |
妇产科学 | 39篇 |
基础医学 | 314篇 |
口腔科学 | 100篇 |
临床医学 | 295篇 |
内科学 | 691篇 |
皮肤病学 | 29篇 |
神经病学 | 99篇 |
特种医学 | 321篇 |
外科学 | 348篇 |
综合类 | 38篇 |
一般理论 | 2篇 |
预防医学 | 245篇 |
眼科学 | 15篇 |
药学 | 106篇 |
中国医学 | 3篇 |
肿瘤学 | 176篇 |
出版年
2022年 | 21篇 |
2021年 | 45篇 |
2020年 | 28篇 |
2019年 | 45篇 |
2018年 | 48篇 |
2017年 | 41篇 |
2016年 | 43篇 |
2015年 | 56篇 |
2014年 | 64篇 |
2013年 | 95篇 |
2012年 | 124篇 |
2011年 | 102篇 |
2010年 | 76篇 |
2009年 | 94篇 |
2008年 | 104篇 |
2007年 | 92篇 |
2006年 | 101篇 |
2005年 | 89篇 |
2004年 | 62篇 |
2003年 | 69篇 |
2002年 | 56篇 |
2001年 | 54篇 |
2000年 | 64篇 |
1999年 | 63篇 |
1998年 | 72篇 |
1997年 | 82篇 |
1996年 | 74篇 |
1995年 | 55篇 |
1994年 | 62篇 |
1993年 | 66篇 |
1992年 | 58篇 |
1991年 | 38篇 |
1990年 | 38篇 |
1989年 | 66篇 |
1988年 | 59篇 |
1987年 | 54篇 |
1986年 | 51篇 |
1985年 | 49篇 |
1984年 | 46篇 |
1983年 | 33篇 |
1982年 | 32篇 |
1981年 | 28篇 |
1980年 | 32篇 |
1979年 | 20篇 |
1978年 | 22篇 |
1977年 | 21篇 |
1976年 | 25篇 |
1975年 | 34篇 |
1973年 | 20篇 |
1968年 | 18篇 |
排序方式: 共有2949条查询结果,搜索用时 15 毫秒
991.
992.
Continuous irradiation of the lewis lung carcinoma in vivo at clinically-used “ultra” low-dose-rates
William U. Shipley John H. Peacock G.Gordon Steel Trevor C. Stephens 《International journal of radiation oncology, biology, physics》1983,9(11):1647-1653
The in vivo response of the transplantable Lewis lung tumor to continuous irradiation (CI) at the clinical “ultra” low-dose-rates of 10–30 cGy/h was investigated. Tumor-bearing mice were housed in a dedicated 137Cs unit for up to three weeks while receiving Cl. The horizontal 137Cs beam allowed secondary shielding of the lower body, but full irradiation of the dorsally-placed tumor and part of the upper body. Radiation survival curves were measured using an excision assay and tumor-cell colony formation in soft agar. The relative cell survival per tumor decreased exponentially with time and the irradiation periods required to reach a surviving fraction of 10?3 at the three dose-rates (10, 15 and 30 cGy/h) were 15.4, 10.2 and 4.3 days. As a function of dose, the survival curves were exponential and indistinguishable betwen the three dose-rates, the aveage D0 value being 5.04 Gy. Neither the hypoxic fraction of the tumor nor the intrinsic cellular radiosensitivity were altered in the tumor cells surviving Cl. The effects of the three dose-rates on the growth of Lewis lung tumors differed considerably, with clear volume regression at the highest dose rate (30 cGy/h) and exponential decreases in clonogenic cells per tumor with time at 15 and 30 cGy/h. Since the overall effect of CI is determined by the competition between cell killing and cell repopulation, the response of slowly-growing human tumors should be proportionately greater. 相似文献
993.
G S Ogilvie M Krajden D J van Niekerk R E Martin T G Ehlen K Ceballos L W Smith L Kan D A Cook S Peacock G C E Stuart E L Franco A J Coldman 《British journal of cancer》2012,107(12):1917-1924
Background:
Round 1 data of human papillomavirus (HPV) FOCAL, a three-arm, randomised trial, which aims to establish the efficacy of HPV DNA testing as a primary screen for cervical cancer, are presented.Methods:
The three arms are: Control arm – liquid based cytology with atypical squamous cells of unknown significance (ASC-US) triage with hrHPV testing; Intervention Arm – hrHPV at entry with liquid-based cytology (LBC) triage of hrHPV positives, with exit screen at 4 years; Safety check arm – hrHPV at entry with LBC triage of hrHPV positives with exit screen at 2 years.Results:
A total of 6154 women were randomised to the control arm and 12 494 to the HPV arms (intervention and safety check). In the HPV arm, the baseline cervical intraepithelial neoplasia (CIN)2+ and CIN3+ rate was 9.2/1000 (95%CI; 7.4, 10.9) and 4.8/1000 (95%CI; 3.6, 6.1), which increased to 16.1/1000 (95%CI 13.2, 18.9) for CIN2+ and to 8.0/1000 (95%CI; 5.9, 10.0) for CIN3+ after subsequent screening of HPV-DNA-positive/cytology-negative women. Detection rate in the control arm remained unchanged after subsequent screening of ASC-US-positive/hrHPV DNA-negative women at 11.0/1000 for CIN2+ and 5.0/1000 for CIN3+.Conclusion:
After subsequent screening of women who were either hrHPV positive/cytology negative or ASC-US positive/HPV negative, women randomised to the HPV arms had increased CIN2+ detection compared with women randomised to the cytology arm. 相似文献994.
Eleven human lung tumour lines have been established in xenograft or tissue culture, and the responses to acute irradiation of the 10 lines which cloned in soft agar were assayed. In vitro radiosensitivity was evaluated using the multitarget and linear quadratic models of cell survival and the surviving fraction at 2 Gy. Significant differences in the response of the different cell types were found, the large-cell phenotype exhibiting radioresistance, and small-cell carcinomas and adenocarcinomas being radiosensitive. No differences in the capacity of the different tumour types to repair radiation damage were demonstrated. In vivo and spheroid response was modified by the effects of hypoxia and cell-contact phenomena. The results suggested that hyperfractionation would be useful in the clinical management of adenocarcinoma and small-cell carcinoma. 相似文献
995.
W B Conover R L Yarwood M D Peacock B A Thomas 《American journal of obstetrics and gynecology》1986,155(4):846-847
Neonatal seizures have been observed as early as the first hour of life. It has been postulated that for certain central nervous system disorders, seizure activity may occur in utero. This report describes two cases of spontaneous fetal seizure activity diagnosed by real-time ultrasound. 相似文献
996.
J S Deitch G W Plonk C Hagenstad K J Hansen J E Peacock J Ligush 《Journal of vascular surgery》1999,30(1):189-192
Mycotic processes occasionally complicate atherosclerotic aortic disease and usually require aggressive surgical therapy to control sepsis and prevent arterial rupture. Rarely, fungal organisms are responsible for primary infection of the abdominal aorta. We report the first case of Cryptococcal aortitis presenting as a ruptured abdominal aortic aneurysm. The surgical, pathologic, and microbiologic aspects of fungal aortitis are discussed. 相似文献
997.
Genes controlling fertilization-independent seed development in
Arabidopsis thaliana 总被引:22,自引:0,他引:22 下载免费PDF全文
998.
C Wilfert JE Aronson DT Beck AR Fleischman MW Kline LM Mofenson GB Scott DW Wara PN Whitley-Williams 《Pediatrics》1999,103(2):509-511
Although the character of acquired immunodeficiency syndrome is changing into a chronic illness, it is estimated that by the end of this century, 80 000 children and adolescents in the United States will be orphaned by parental death caused by human immunodeficiency virus infection. Plans for these children need to be made to ensure not only a stable, consistent environment that provides love and nurturing, but also the medical and social interventions necessary to cope with the tragic loss. Pediatricians should become aware of local laws and community resources and initiate discussion early in the course of parental illness to facilitate planning for the future care and custody of the children. States need to adopt laws and regulations that provide flexible approaches to guardianship and placement of children orphaned by acquired immunodeficiency syndrome. 相似文献
999.
S F Weber J E Peacock K A Do J M Cruz B L Powell R L Capizzi 《Infection control and hospital epidemiology》1990,11(5):235-242
A clinicoepidemiologic study was undertaken to investigate an apparent increase in frequency of nosocomial invasive filamentous fungal disease (NIFFD) in adult patients with acute leukemia hospitalized during a period of hospital construction, and to determine if a relationship existed between the construction activity and the acquisition of NIFFD. The first study goal, to determine the incidence of NIFFD before and during construction, was approached by calculation of incidence rates of NIFFD in patients with acute leukemia, comparing 1982 and 1983 (a baseline period free of construction) to 1986 (a year when construction activity was at its peak). The second study goal, to identify risk factors for the development of NIFFD, was accomplished by reviewing the autopsy records of all patients with underlying hematologic disorders accompanied by granulocytopenia who died in our hospital from 1982 through 1986. Patients with and without autopsy evidence of NIFFD were then compared by univariate and multivariate (logistic regression) analysis to identify potential risk factors for the acquisition of NIFFD. The incidence of NIFFD in patients with acute leukemia hospitalized during the period of hospital construction was significantly increased when compared to a baseline period without construction (11 per 139 versus 4 per 333, p less than .001). Review of all granulocytopenic patients autopsied over the five-year interval 1982 through 1986 revealed duration of granulocytopenia and hospitalization during construction to be risk factors for NIFFD by univariate analysis (p less than .005). Logistic regression showed duration of granulocytopenia to be highly significant independent risk factor (p less than .01) and construction activity to be a probable independent risk factor (p = .09).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
1000.
Prostacyclin expression by a continuous human cell line derived from vascular endothelium 总被引:4,自引:0,他引:4
Prostacyclin is primarily an endothelial cell product. It contributes to the important role of endothelium in maintaining the fluidity of blood by inhibiting platelet aggregation and by promoting vasodilation. Endothelial cells in culture tend to senesce, and the level of prostacyclin expression decreases. A permanent human cell line, EA.hy 926, derived from a fusion of primary endothelial cells with cells of a less differentiated line, has been found to sustain basal and stimulated levels of prostacyclin synthesis. 相似文献