全文获取类型
收费全文 | 5677篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 2篇 |
化学工业 | 46篇 |
金属工艺 | 1篇 |
机械仪表 | 6篇 |
建筑科学 | 9篇 |
能源动力 | 4篇 |
轻工业 | 12篇 |
水利工程 | 2篇 |
无线电 | 18篇 |
一般工业技术 | 36篇 |
冶金工业 | 5501篇 |
原子能技术 | 3篇 |
自动化技术 | 40篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2017年 | 3篇 |
2014年 | 2篇 |
2013年 | 16篇 |
2012年 | 7篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 3篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 168篇 |
1998年 | 1687篇 |
1997年 | 936篇 |
1996年 | 592篇 |
1995年 | 339篇 |
1994年 | 300篇 |
1993年 | 314篇 |
1992年 | 41篇 |
1991年 | 62篇 |
1990年 | 75篇 |
1989年 | 64篇 |
1988年 | 70篇 |
1987年 | 72篇 |
1986年 | 55篇 |
1985年 | 66篇 |
1984年 | 2篇 |
1983年 | 13篇 |
1982年 | 29篇 |
1981年 | 34篇 |
1980年 | 57篇 |
1979年 | 6篇 |
1978年 | 16篇 |
1977年 | 158篇 |
1976年 | 347篇 |
1975年 | 6篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1955年 | 4篇 |
排序方式: 共有5684条查询结果,搜索用时 0 毫秒
31.
Since the advent of computed tomography (CT) traumatic intraventricular haemorrhage (IVH) has been diagnosed more often. It has reportedly been associated with a poor prognosis, but pure or solitary IVH is rare, suggesting that other lesions occurring concurrently with it may contribute to the poor outcome. In a series of 65 patients with severe head injury (GCS < or = 8), 14 (22%) had IVH on initial CT. Death rate in these 14 was 21%, not significantly different from that in patients without IVH (14%), although a significantly higher proportion of patients without IVH had a good outcome. These results suggest that mortality is related to other lesions associated with IVH rather than to IVH alone and that the presence of IVH does not necessarily lead to a poor outcome. 相似文献
32.
EM de Kleijn WJ Oyen RA Claessens FH Corstens JW van der Meer 《Canadian Metallurgical Quarterly》1995,155(18):1989-1994
BACKGROUND: We assessed the utility of scintigraphy with indium 111-labeled polyclonal human IgG scintigraphy in patients with fever of unknown origin that fulfilled the criteria of temperature of 38.3 degrees C or more for at least 3 weeks and no diagnosis during 1 week of hospital admission. We compared the utility of this technique with results of scintigraphic techniques reported in the literature. METHODS: Data for all patients seen at our university hospital in whom 111In-IgG scanning was performed were analyzed and checked for the criteria for fever of unknown origin. The literature on the utility of scintigraphic techniques in patients with fever of unknown origin was reviewed. RESULTS: We studied 24 patients with fever of unknown origin. In 13 patients, focal 111In-IgG accumulation was observed. In nine (38%) of those, the positive 111In-IgG scintigram led to the final diagnosis; in the other four patients (17%), the scintigraphic findings were not helpful. In the 11 patients with negative 111In-IgG scans, extensive diagnostic workup produced no infection as the final diagnosis in nine patients (38%), one had an abscess in a renal cyst that was detected several months later, and in the other the cause of fever was an infected intravenous line. The overall sensitivity and specificity of 111In-IgG scintigraphy were 81% and 69%, respectively. The positive predictive value was 69% and the negative predictive value was 82%. CONCLUSIONS: Our results show that 111In-IgG scintigraphy significantly contributed to the diagnostic process in patients with fever of unknown origin. A positive scan increased the likelihood of finding the cause of the fever, and a negative scan ruled out an inflammatory component with a high degree of certainty. These data compare favorably with data in the literature concerning other radiopharmaceuticals; a larger prospective evaluation of this technique is indicated. 相似文献
33.
34.
35.
H Rodgers M Sudlow R Dobson RA Kenny RG Thomson 《Canadian Metallurgical Quarterly》1997,47(418):309-310
The demand for anticoagulation services is rising. Warfarin anticoagulation has been shown to reduce the risk of stroke in patients with non-valvular atrial fibrillation by 68%. This raises issues about how services are best organized to initiate and monitor anticoagulation in this potentially large group of patients. We report the results of a regional postal survey undertaken to describe the views of general practitioners and consultants regarding warfarin anticoagulation in light of this potentially high increase in demand. 相似文献
36.
37.
38.
A dynamic investigation was done of the immunologic status in 75 patients with purulent surgical lesions of soft tissues. Applied in the complex of therapeutic measures was intracorporeal irradiation of blood with ultraviolet light under control of partial pressure of oxygen and carbon dioxide. The above irradiation was found out to make for a more rapid and marked stabilization of bodily immunologic status. 相似文献
39.
Antisera made against whole cells of Bordetella avium protected turkeys against disease signs of turkey coryza, but antiserum against the dermonecrotic heat-labile toxin (DHLT) did not. Neither antiserum against whole cells nor antiserum against DHLT protected turkeys against colonization of the trachea by B. avium. At least 25 bands in whole cell lysate of B. avium separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) reacted in immunoblots with protective antiserum. These bands occurred at < 40 kDa and > 105.3 kDa. DHLT had an isoelectric point (pI) in the range pH 6.3-6.7. Following SDS-PAGE of isoelectric-focused fractions, two bands were recognized by anti-DHLT with immunoblots of pI 6.3, pI 6.5, and pI 6.7 fractions separated by SDS-PAGE. 相似文献
40.