全文获取类型
收费全文 | 753篇 |
免费 | 0篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 21篇 |
金属工艺 | 6篇 |
机械仪表 | 8篇 |
建筑科学 | 2篇 |
能源动力 | 1篇 |
轻工业 | 10篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 25篇 |
一般工业技术 | 49篇 |
冶金工业 | 622篇 |
原子能技术 | 3篇 |
自动化技术 | 5篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 8篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 22篇 |
1998年 | 220篇 |
1997年 | 118篇 |
1996年 | 95篇 |
1995年 | 43篇 |
1994年 | 39篇 |
1993年 | 38篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有759条查询结果,搜索用时 15 毫秒
751.
752.
Clinically significant spinal implants develop in intracranial ependymomas. Spinal subarachnoid implants developed in 11 of 32 patients who received local irradiation at the University of Michigan between 1955 and 1972 for intracranial ependymoma. Seven of these patients received spinal axis irradiation for neurological disturbances resulting from the implants, and implants were found in the other 4 patients postmortem. Ten patients had infratentorial tumors, and one had a supratentorial tumor; nine tumors were poorly differentiated, two were well differentiated. The authors conclude that spinal irradiation is required if the tumor is poorly differentiated, or located in the infratentorial fossa. 相似文献
753.
754.
OBJECTIVE: To examine the role of tumor necrosis factor-alpha (TNF-alpha) in producing acute inflammatory lung injury after hemorrhage and resuscitation. DESIGN: Prospective, controlled animal study. SETTING: Research laboratory. SUBJECTS: Male BALB/c mice. INTERVENTIONS: Treatment with rat antimouse monoclonal anti-TNF-alpha antibodies or control rat immunoglobulin G 1 hr after 30% blood volume hemorrhage and resuscitation. MEASUREMENTS AND MAIN RESULTS: Therapy with monoclonal anti-TNF-alpha antibodies prevented the posthemorrhage increases in pulmonary TNF-alpha and interferon-gamma protein levels that normally occur after blood loss. Administration of monoclonal anti-TNF-alpha antibodies also diminished the increases in interleukin-1 beta, interleukin-6, and interleukin-10 mRNA, but not the increases in TNF-alpha and interferon-gamma mRNA, which are found in the lungs following hemorrhage. In addition, therapy with monoclonal anti-TNF-alpha antibodies was associated with significant improvement in the histologic parameters of posthemorrhage lung injury, particularly intra-alveolar hemorrhage and pulmonary vascular congestion. CONCLUSIONS: These results indicate that TNF-alpha has an important role in the development of acute inflammatory lung injury after blood loss. Blockade of TNF-alpha with monoclonal antibodies significantly reduces hemorrhage-induced lung injury. 相似文献
755.
756.
757.
S. Prakash Parthiban Ill Yong Kim Koichi Kikuta Chikara Ohtsuki 《Materials science & engineering. C, Materials for biological applications》2011,31(7):1383-1388
The effect of urea on the formation of hydroxyapatite (HAp) was studied by employing the double-step hydrothermal processing of a powder mixture of beta-tricalcium phosphate (β-TCP) and dicalcium phosphate dihydrate (DCPD). Co-existence of urea was found to sustain morphology of HAp crystals in the compacts under an initial concentration of 2 mol dm-3 and less. Homogenous morphology of needle-like crystals was observed on the compacts carbonated owing to decomposition of urea. Carbonate ions (CO32-) was found to be substituted in both the phosphate and hydroxide sites of HAp lattice. The synthesized HAp was calcium deficient, as it had a Ca/P atomic ratio of 1.62 and the phase was identified as calcium deficient hydroxyapatite (CDHA). The release of CO32- ions from urea during the hydrothermal treatment determined the morphology of the CDHA in the compacts. The usage of urea in the morphological control of carbonate-substituted HAp (CHAp) employing the double-step hydrothermal method is established. 相似文献
758.
We examined the developmental profile of a kazal-type trypsin inhibitor (P12) of Mr 6126 in mouse seminal vesicle, characterized its binding sites on the surface of sperm, and assessed its effect on Ca2+ uptake by spermatozoa. Among the genital tracts of adult mice, P12 was found only in the male accessory glands including seminal vesicle, coagulating gland, and prostate. It was immunolocalized on the luminal epithelium of the primary and secondary folds in both the seminal vesicle and coagulating gland, and on the folds projecting into the lumen of the glandular alveolus in the prostate. The protein and its RNA message in seminal vesicle did not appear in the prepubertal period, but expression coincided with maturation. Castration of adult mice resulted in cessation of P12 expression. Treatment of the castrated mice with testosterone propionate in corn oil restored the protein expression in the seminal vesicle. Spermatozoa collected from caudal epididymis were devoid of P12. Cytochemical study illustrated a P12-binding region on the anterior acrosomes of cells preincubated with P12. Analysis of equilibrium data from the binding assay using 125I-P12 with a Scatchard plot showed a single type of P12-binding sites on sperm, with an apparent dissociation constant of 70.15 +/- 5.25 nM and the capacity of 1.49 +/- 0.06 x 10(6) binding sites/cell. The protein could serve as a calcium transport inhibitor to suppress a great extent of Ca2+ uptake by spermatozoa. The immunohistochemical staining patterns of testis revealed that the P12-binding sites appeared on postmeiotic cells such as spermatids and spermatozoa, but were absent in Leydig cells, Sertoli cells, spermatogonia, and spermatocytes in seminiferous tubules. 相似文献
759.
The purpose of this study was to assess the related factors to the healthy lifestyle of 1147 urban employees. The theoretical framework of this study was the PRECEDE model. The model included three factors: 1. predisposing factors cardiovascular disease knowledge, general self-efficacy, health related diet and exercise self-efficacy, attitude for maintaining healthy life-style, health value, health status and illness history of family); 2. enabling factors (health resource availability, health resource utility); and 3. reinforcing factors (social support, feelings of colleagues health practice); The three factors were measured by 12 scales, through which the reliability and validity were assessed. According to the stepwise multiple regression analysis, diet and exercise self-efficacy, attitude for maintaining healthy life-style, marital status, cardiovascular disease knowledge, health status, occupational level, social support and feel of colleague health practice were the significant factors which accounted for 38.2% of variance. Predisposing factors and reinforcing factors were the important factors of healthy lifestyle on urban employees. 相似文献