全文获取类型
收费全文 | 269篇 |
免费 | 16篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 92篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 19篇 |
能源动力 | 4篇 |
轻工业 | 22篇 |
水利工程 | 1篇 |
石油天然气 | 5篇 |
无线电 | 7篇 |
一般工业技术 | 38篇 |
冶金工业 | 35篇 |
自动化技术 | 49篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 14篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 14篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 6篇 |
2008年 | 21篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1969年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有285条查询结果,搜索用时 0 毫秒
21.
S Briault R Hill A Shrimpton D Zhu M Till N Ronce P Margaritte-Jeannin M Baraitser H Middleton-Price S Malcolm E Thompson J Hoo G Wilson C Romano A Guichet M Pembrey M Fontes A Poustka C Moraine 《Canadian Metallurgical Quarterly》1997,73(1):87-90
AIMS: An increased risk of adenocarcinoma of the oesophagus has been demonstrated in patients with long segments of Barrett's mucosa. The risk of cancer associated with short segments of metaplasia of the oesophagogastric junction is not known. METHODS AND RESULTS: We report a case of early adenocarcinoma of the oesophagus arising on short tongues of Barrett's mucosa associated with an oesophageal cyst. The patient was a 68-year-old man with no previous clinical history of gastro-oesophageal reflux disease. The fortuitous discovery of an oesophageal cyst lead to the diagnosis of short tongues of Barrett's mucosa with high-grade dysplasia. On pathological examination of the resected specimen, an early adenocarcinoma had developed in Barrett's mucosa, localized just above the oesophageal cyst. CONCLUSIONS: As oesophageal cysts can cause symptoms suggestive of reflux, we hypothesize that this association may not be fortuitous. 相似文献
22.
DM Colton GO Till KJ Johnson SB Dean RH Bartlett RB Hirschl 《Canadian Metallurgical Quarterly》1998,26(10):1716-1724
OBJECTIVE: This study evaluates the ability of perflubron to inhibit pulmonary neutrophil accumulation during partial liquid ventilation (PLV) in the setting of acute lung injury. DESIGN: Randomized, controlled, nonblinded study. SETTING: Research laboratory at a university. SUBJECTS: Male, Sprague-Dawley rats (n = 120, 506 +/- 42 g). INTERVENTIONS: Animals were divided into eight groups (n = 15 in each group, of which n = 12 for myeloperoxidase content and n = 3 for histologic neutrophil counting): a) GV-CVF group, animals received gas ventilation (GV) with the induction of lung injury using cobra venom factor (CVF); b) PLV-CVF group, animals received partial liquid ventilation before the induction of lung injury; c) PEEP-CVF group, animals received positive end-expiratory pressure (PEEP) before the administration of cobra venom factor; d) CVF-PLV group, animals received partial liquid ventilation after cobra venom factor; e) CVF-PEEP group, animals received PEEP after cobra venom factor; f) PLV only group, animals received partial liquid ventilation only; g) GV only group, animals received gas ventilation only; and h) NVSBA group, nonventilated spontaneous breathing animals. MEASUREMENTS AND MAIN RESULTS: After the experimental period, total lung myeloperoxidase content was significantly decreased in the PLV-CVF (0.29 +/- 0.08, p = .02) and PEEP-CVF (0.34 +/- 0.04, p = .01) groups when compared with the GV-CVF group (0.62 +/- 0.07). When compared with the GV-CVF group, a trend toward a reduction in myeloperoxidase was observed in the CVF-PLV (0.42 +/- 0.05, p = .07) and the CVF-PEEP (0.39 +/- 0.06, p = .07) groups. When compared with the cobra venom factor only group (GV-CVF 47 +/- 2 neutrophils/high-power field), reductions in neutrophil count were observed in all groups (neutrophils/high-power field): PLV-CVF (20 +/- 2, p = .009); PEEP-CVF (24 +/- 1, p = .01); CVF-PLV (30 +/- 2, p = .03); and CVF-PEEP (37 +/- 1, p = .04). CONCLUSION: These data suggest that both partial liquid ventilation and PEEP result in a reduction in neutrophil accumulation in the setting of acute lung injury. 相似文献
23.
A report is given about a patient aged 57 years, who developed a transitional cell carcinoma of the Bartholin's gland. Transitional cell carcinomas of the vulva are rare neoplasms. To the best of our knowledge only eight cases are reported in the literature including this case. In context with the international literature etiopathogenetic theories, therapeutic and prognostic aspects of the disease are discussed. 相似文献
24.
In the nineteen-thirties and -forties, genes were universally believed to be made of protein. Biochemists met Avery, MacLeod and McCarty's discovery, that the transforming factor of pneumococci consists of DNA, with disbelief, and the notion that this was true of genes took a long time to be generally accepted even after Watson and Crick's discovery of its double helical structure. Until Watson's arrival, Kendrew, Crick and I were interested mainly in solving the structure of proteins, but Watson made us think about the structure of genes which determine protein structure. 相似文献
25.
26.
The records of 21 children with neuroblastoma presenting with spinal cord compression, encountered over 17 years, were reviewed. Thirteen patients (61%) survive, free of neuroblastoma, at intervals ranging from nine months to 192 months (median, 78 months) from the time of diagnosis. The explanation for this relatively high survival rate was sought in an analysis of the cases which took into account age, site, extent of disease, and histology. The most significant features to emerge were the unusually high proportion of children under 12 months of age at presentation (11 of 21) most of whom survive (9 of 11) and the low incidence (3 of 21) of detectable at the time of diagnosis. The absence of a paraspinal mass was an unfavourable prognostic features (1 of 6 survives) whilst if a paraspinal mass was present, its anatomical level did not influence survival. In particular, children with retroperitoneal tumors fared no worse (survival, 6 of 7) than those with primary tumors at other sites (survival, 6 of 8). Morbidity was high (6 of 13), principally in infants with spinal cord compression from birth. Survival was also related to the histologic maturity of the tumor, even in the presence of metastases. Recommendations for management are made. 相似文献
27.
Theory of Computing Systems - Given a hypergraph H = (V,E), what is the smallest subset $X \subseteq V$ such that e ∩ X≠∅ holds for all e ∈ E? This problem, known as the... 相似文献
28.
Florian Weyland Thorsten Eisele Sebastian Steiner Till Frömling George A. Rossetti Jürgen Rödel Nikola Novak 《Journal of the European Ceramic Society》2018,38(2):551-556
The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr0.2Ti0.8)O3 ceramics which reveal that the adiabatic temperature change, polarization-electric field hysteresis loops and dielectric permittivity/loss show stable behavior up to 105 cycles. We further demonstrate that the loss in electrocaloric response observed after 105 cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 105 cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 106 cycles, much higher than achieved in commercially available barium titanate ceramics. 相似文献
29.
30.