全文获取类型
收费全文 | 3914篇 |
免费 | 26篇 |
专业分类
电工技术 | 16篇 |
综合类 | 16篇 |
化学工业 | 147篇 |
金属工艺 | 29篇 |
机械仪表 | 46篇 |
建筑科学 | 50篇 |
矿业工程 | 9篇 |
能源动力 | 6篇 |
轻工业 | 86篇 |
水利工程 | 11篇 |
石油天然气 | 4篇 |
武器工业 | 2篇 |
无线电 | 74篇 |
一般工业技术 | 182篇 |
冶金工业 | 3135篇 |
原子能技术 | 7篇 |
自动化技术 | 120篇 |
出版年
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 15篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 20篇 |
2013年 | 32篇 |
2012年 | 31篇 |
2011年 | 51篇 |
2010年 | 27篇 |
2009年 | 36篇 |
2008年 | 44篇 |
2007年 | 81篇 |
2006年 | 57篇 |
2005年 | 37篇 |
2004年 | 29篇 |
2003年 | 32篇 |
2002年 | 28篇 |
2001年 | 23篇 |
2000年 | 27篇 |
1999年 | 108篇 |
1998年 | 880篇 |
1997年 | 516篇 |
1996年 | 310篇 |
1995年 | 206篇 |
1994年 | 175篇 |
1993年 | 192篇 |
1992年 | 34篇 |
1991年 | 60篇 |
1990年 | 44篇 |
1989年 | 49篇 |
1988年 | 45篇 |
1987年 | 45篇 |
1986年 | 55篇 |
1985年 | 49篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 22篇 |
1981年 | 38篇 |
1980年 | 34篇 |
1979年 | 13篇 |
1978年 | 26篇 |
1977年 | 107篇 |
1976年 | 190篇 |
1975年 | 19篇 |
1972年 | 9篇 |
1971年 | 9篇 |
1967年 | 6篇 |
排序方式: 共有3940条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
Clinical and hemodynamic criteria for use of the intra-aortic balloon pump in patients requiring cardiac surgery 总被引:1,自引:0,他引:1
H Bolooki W Williams RJ Thurer A Vargas GA Kaiser F Mack AR Ghahramani 《Canadian Metallurgical Quarterly》1976,72(5):756-768
In order to establish criteria for elective use of the intra-aortic balloon pump (IABP) in patients having cardiac surgery, we conducted a retrospective study of 43 patients who required counterpulsation, because of inability to be weaned from cardiopulmonary bypass, between May, 1972, and June, 1974. Patients in cardiogenic shock preoperatively were excluded. The 43 patients included 23 (Group A) who had severe preoperative left ventricular dysfunction with a mean cardiac index less than 1.8 L. per minute per square meter, ejection fraction less than 30 per cent, and end-diastolic pressure greater than 22 mm. Hg; 20 patients (Group B) had a combination of moderate cardiac dysfunction (cardiac index less than 2.2, ejection fraction less than 40, end-diastolic pressure less than 18) in the presence of acute infarction or severe aortic stenosis (gradient greater than 80 mm. Hg) with or without coronary disease. An inverse relationship was noted between survival and delay from completion of operation to the use of 1ABP. Thirty-two of 43 patients were weaned off bypass and were balloon assisted for 12 to 96 hours postoperatively; 25 patients were discharged (58 per cent). In Subgroup A, 14 of 23 (60 per cent) and, in Subgroup B, 9 of 20 (45 per cent) were long-term survivors. Based on these findings, 45 patients were operated upon between June, 1974, and December, 1975, with elective use of 1ABP and were assessed by serial hemodynamic studies. Sixteen had severe preoperative left ventricular dysfunction similar to Subgroup A and 29 had moderate dysfunction in combination with pathology similar to Subgroup B. Fifteen of these patients were hemodynamically unstable at time of arrival in the operating room; 1ABP was inserted under local anesthesia. Thirty-nine patients (87 per cent) were weaned off bypass and were hospital survivors. In Subgroup A, 13 of 16 (81 per cent) and, in Group B, 21 of 29 (72 per cent) were long-term survivors. Criteria for elective use of 1ABP in cardiac surgery should include severe preoperative left ventricular dysfunction or a combination of moderate dysfunction with coronary or valvular pathology. Elective 1ABP improves the survival with trivial iatrogenic morbidity. 相似文献
36.
Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) was administered in a dose of 20 mg/kg/d to 21 patients with symptomatic Paget's disease. All patients were treated for 6 months and then followed for an additional 6 months. There was a striking decline in serum alkaline phosphatase and urinary hydroxy-proline excretion observed after 3 months of therapy which was not significantly improved in the succeeding 3 months. Concomitantly there was marked improvement in clinical symptoms and bone scans. Following cessation of therapy, continued biochemical and clinical evidence of remission persisted. Several patients on repeat treatment with EHDP appeared to respond promptly. Side effects were minimal except for a possibly related osteomalacia and increased incidence of pathologic fractures. 相似文献
37.
This study was concerned with psychotherapists' evaluations of the outcome of therapy. Staff and resident psychiatrists employed in 23-item questionnaire to rate the seccess of psychotherapy with 85 of their inpatients. These were patients for whom psychotherapy constituted a significant part of the treatment that they received in the hospital. The therapists' responses to the questionnaire items were intercorrelated. The results indicated that a major aspect of a psychotherapist's judgment of the success of treatment-as these judgments usually are employed in current psychotherapy research-is the therapist's affective reaction to the patient, Better-liked patients were viewed as having improved more. However, when the therapists' responses were subjected to factor analysis, independent Improvement and Affection factors emerged. It is suggested that when therapists' ratings of success are used in psychotherapy research they should be treated or refined statistically to minimize potential confounding with their affection for patients. 相似文献
38.
AD Lelianov IuG Novikov GA Rusanov NE Siniavskaia 《Canadian Metallurgical Quarterly》1976,116(4):24-28
In experiments on 50 dogs with toxic acute edema of the lung, induced with intravenous injection of 0.1% silver nitrate, the authors have studied the efficacy of accessory artificial circulation and "conservative" therapy. During the perfusion a discharge of the right portions, adequate extracorporeal gas metabolism, normalization of blood gas and acid-base balance were noted; an intensity of pulmonary edema is descreased. An intensive therapy for pulmonary edema was found to be more effective in association of "conservative" treatment with venoarterial perfusion and blood oxygenation. 相似文献
39.
40.
The effects of total (T-NSB) and subtotal (S-NSB) destruction of the nigrostriatal bundle were compared with the effects of large lateral hypothalamic (LH) lesions on various aspects of the lateral hypothalamic syndrome. The T-NSB and LH lesions produced equivalent decreases in caudate and telencephalic contents of dopamine and norepinephrine, while with the exception of telencephalic dopamine, S-NSB lesions had consistently smaller effect. The T-NSB and LH lesions produced equivalent effects on duration of aphagia and adipsia (Stages 1 to 3) and on long-term decreases in body weight and ad lib water consumption, and these effects were always greater than those produced by the S-NSB lesion. These aspects of the lateral hypothalamic syndrome appeared to be related to the interruption of the nigrostriatal bundle and consequent decrease in caudate dopamine. The T-NSB and S-NSB lesions produced equivalent long-term deficits in water regulation as measured by drinking in the absence of food or in response to intra- and extracellular dehydration, but these deficits were always significantly less than those produced by the LH lesion. It was concluded that these regulatory deficits were not related to destruction of catecholamine pathways. All three lesions totally blocked eating in response to a glucoprivic challenge. This aspect of the lateral hypothalamic syndrome, therefore, results from destruction of a small portion of the lateral diencephalon and may be related to the interruption of the dopaminergic mesolimbic system. 相似文献