全文获取类型
收费全文 | 861篇 |
免费 | 0篇 |
专业分类
化学工业 | 2篇 |
建筑科学 | 1篇 |
轻工业 | 2篇 |
石油天然气 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 2篇 |
冶金工业 | 840篇 |
原子能技术 | 1篇 |
自动化技术 | 9篇 |
出版年
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
1999年 | 26篇 |
1998年 | 233篇 |
1997年 | 140篇 |
1996年 | 106篇 |
1995年 | 50篇 |
1994年 | 45篇 |
1993年 | 58篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 15篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 24篇 |
1976年 | 56篇 |
1975年 | 3篇 |
1955年 | 2篇 |
排序方式: 共有861条查询结果,搜索用时 15 毫秒
21.
22.
We sought to estimate the impact of maternal HIV testing and prenatal care on the potential to reduce vertical transmission through zidovudine (AZT) use by HIV-infected mothers. We evaluated the prepartum maternal HIV diagnosis rate, prenatal care, disease stage, and vertical transmission rate (from a two-part mixture model) using New York State Medicaid and vital statistics data for HIV-infected mothers and their singletons in 1985-90. We used published data to estimate the effect of AZT on vertical transmission and expert input to define other parameters for the model. Our HIV-infected (N = 1514) had a vertical transmission rate of 27.0%. HIV was diagnosed prepartum for 39.5% of women in 1990. Transmission would have been 22.2% if AZT had been taken only by the subset of women diagnosed prepartum with HIV and receiving prenatal care by 34 weeks gestation (86.7%). Transmission would have dropped to 11.2% if all women had been diagnosed prepartum with HIV and received adequate prenatal care. The observed deficiencies in prenatal care and maternal HIV diagnosis rates in this Medicaid population-based cohort must be addressed to realize the promise of AZT to reduce vertical transmission. 相似文献
23.
24.
25.
26.
27.
The object was to study retrospectively the perioperative complications and results of the Bologna procedure for the treatment of stress urinary incontinence associated with cystocele grade 2 or more. In the study, 80 patients underwent a repair of all defects of pelvic support plus the Bologna procedure. Mean duration of follow-up was 40.2 months (range 3-127). The incidence of operative complications was 2.5% for inadvertent cystostomy and for hemorrhage. Mean hospital stay was 7.2 days (range 2-17). At 2-year follow-up 85% of the patients were completely free of incontinence symptoms (95% CI: 75-92) and 76% at 3-year follow-up (95% CI: 66-86). None of the parameters tested in a univariate analysis was independently linked with surgical failure. Further studies are needed to establish the place of this technique in the surgical management of urinary incontinence associated with genital prolapse. 相似文献
28.
RN Jones MA Pfaller SA Marshall RJ Hollis WW Wilke 《Canadian Metallurgical Quarterly》1997,29(3):187-192
From March 1989 to March 1993, six athletic patients were treated in our institution by thrombolytic therapy for acute effort axillary-subclavian vein thrombosis in thoracic outlet syndrome. Mean age of these patients was 20 (range 14 to 27). An in situ infusion with urokinase (2,500 U/kg/h) and Heparin (100 U/kg/12 hours) was given during 64 hours (Range 14 to 72). Phlebography showed a complete reperfusion in three cases (the treatment began within an average period of 5.6 days), partial reperfusion in two cases (the treatment began within an average period of 8.5 days). In one case there was no reperfusion on phlebography: treatment began within an average period of 15 days. For this patient, a venous axillo-jugular bypass graft was performed. In all cases, there was no bleeding complication. A trans-axillary first rib resection was done three months later. Mean follow up was 31 months (range: two to 51 months). All patients recovered their previous physical status. Echo-Doppler exam showed normal subclavian vein flow in four cases, partial occlusion in one case and a total occlusion of the subclavian vein flow in one case. In this last case, the thrombolytic therapy failed to restore the permeability of the subclavian vein. Bypassgraft was patent. Axillary-subclavian vein thrombosis seen within a period of seven days should be treated by local thrombolytic therapy using urokinase and heparin. 相似文献
29.
Isoelectronic x-ray spectroscopy to determine electron temperatures in long-scale-length inertial-confinement-fusion plasmas 总被引:1,自引:0,他引:1
30.