全文获取类型
收费全文 | 1554篇 |
免费 | 75篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 42篇 |
化学工业 | 429篇 |
金属工艺 | 13篇 |
机械仪表 | 32篇 |
建筑科学 | 43篇 |
矿业工程 | 3篇 |
能源动力 | 77篇 |
轻工业 | 168篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 123篇 |
一般工业技术 | 325篇 |
冶金工业 | 128篇 |
原子能技术 | 11篇 |
自动化技术 | 233篇 |
出版年
2023年 | 10篇 |
2022年 | 72篇 |
2021年 | 87篇 |
2020年 | 43篇 |
2019年 | 38篇 |
2018年 | 50篇 |
2017年 | 31篇 |
2016年 | 55篇 |
2015年 | 48篇 |
2014年 | 59篇 |
2013年 | 118篇 |
2012年 | 96篇 |
2011年 | 111篇 |
2010年 | 95篇 |
2009年 | 67篇 |
2008年 | 78篇 |
2007年 | 59篇 |
2006年 | 58篇 |
2005年 | 48篇 |
2004年 | 45篇 |
2003年 | 33篇 |
2002年 | 38篇 |
2001年 | 17篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 46篇 |
1997年 | 40篇 |
1996年 | 22篇 |
1995年 | 24篇 |
1994年 | 14篇 |
1993年 | 18篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1965年 | 1篇 |
排序方式: 共有1631条查询结果,搜索用时 15 毫秒
121.
Giulietta Smulevich Enrica Droghetti Claudia Focardi Massimo Coletta Chiara Ciaccio Mila Nocentini 《Food chemistry》2007,101(3):1071-1077
Carbon monoxide (CO) can be used to treat fresh meat and fish in order to retain its ‘fresh’ red colour appearance for a longer period of time. In fact, upon aging, myoglobin is oxidized to met-myoglobin with the concomitant blue-shift and broadening of the Soret maximum, which brings about a change in the colour of the fish, revealing that it is no longer fresh. The use of carbon monoxide, which reacts with the oxy-myoglobin to form a fairly stable cherry red carboxy-myoglobin complex may mask spoilage, because the CO-complex can be stable beyond the microbiological shelf life of the meat. The presence of CO in tuna fish has been investigated by optical spectroscopy as the formation of the CO adduct can be easily detected by the combined analysis of electronic absorption spectra in their normal and second derivative modes, monitoring the intense Soret band at 420 nm. The presence of met- and oxy-myoglobin can obscure the presence of small amounts of the CO adduct; however, it can be revealed by chemically reducing the met- and oxy-forms to the deoxy-form in an anaerobic environment. This spectroscopic method provides a qualitatively rapid laboratory screening procedure for food control to unmask the presence of CO in frozen or fresh fish. 相似文献
122.
123.
S Cascinu R Labianca P Alessandroni M Marcellini RR Silva G Pancera E Testa G Martignoni S Barni L Frontini A Zaniboni G Luporini R Cellerino G Catalano 《Canadian Metallurgical Quarterly》1997,15(11):3313-3319
PURPOSE: A multiinstitutional trial was performed to confirm the clinical activity, in terms of response rate and toxicity (primary objectives) and duration of responses and survival (secondary objectives), of an intensive weekly regimen in advanced gastric cancer. PATIENTS AND METHODS: Patients with measurable unresectable and/or metastatic gastric carcinoma received 1-day per week administration of cisplatin (CDDP) 40 mg/m2, fluorouracil (5FU) 500 mg/m2, epi-doxorubicin (epi-ADR) 35 mg/m2, 6S-stereoisomer of leucovorin 250 mg/m2, and glutathione 1.5 g/m2. On the other days, filgrastim was administered by subcutaneous injection at a dose of 5 mg/kg. One cycle of therapy consisted of eight 1-week treatments. Patients who showed a response or stable disease received a further 6 weeks of therapy. RESULTS: Of 105 enrolled patients, 11 had locally advanced unresectable disease only; 33 had primary nonresected and metastatic disease; 48 had metastatic disease and primary tumor resected; 10 had locoregional recurrence and metastatic disease; and three had locoregional recurrence only. After one cycle, 18 complete responses (CRs) and 47 partial responses (PRs) were achieved, for an overall response rate of 62% (95% confidence interval [CI], 53% to 71%). Twenty patients had stable disease and 20 progressed on therapy. The median survival duration of all 105 patients was 11 months, with 1- and 2-year survival rates of 42% and 5%, respectively. World Health Organization (WHO) grade III to IV toxicity, in terms of anemia, neutropenia, thrombocytopenia, and mucositis, was experienced by 40 patients (38%). There were no treatment-related deaths. CONCLUSION: These data support the results of the pilot study and confirmed the high activity of the regimen, with acceptable toxicity. This schedule deserves evaluation in the adjuvant setting. 相似文献
124.
An efficient and simple method for determination of methyl anthranilate (MA) in Citrus spp. honeys by headspace-solid-phase microextraction-gas chromatography (HS-SPME-GC) was developed and validated. Experimental design was used to investigate the effects of the principal extraction parameters. The central composite design (CCD) and the desirability function were used to find the experimental conditions providing the optimal HS-SPME result. Validation was carried out in terms of specificity, linearity, limit of detection (LOD) and quantitation (LOQ) (0.149 and 0.324 μg/g, respectively), method precision (RSD 7%), LOQ precision (RSD 6.5%), and was resulted accurate and robust. Finally, the applicability of the method to the determination of MA in a number of commercial Citrus spp. honey samples was demonstrated, the content ranged from 0.63 to 3.26 μg/g. 相似文献
125.
126.
The influence of temperature, turbidity and oxygen uptakes to the musts on the production of ethanal by yeasts, during the
alcoholic fermentation (AF), has been studied. The aim was to evaluate how increasing and controlling the production of this
molecule, in order to anticipate the reactions between anthocyanins and flavans from the second half of the AF. This concerns,
in particular, those winemaking techniques consisting in a temporarily separate fermentation of a part of the must (35–40%
of the total mass), that is drained before the start of the AF. The experimental design was a complete factorial plan with
three factors upon two levels (T = 18 °C and 22 °C; with or without oxygen; turbidity of 30 and 120 NTU); data were elaborated with 3-ways ANOVA. Temperature
proved to be the main factor influencing ethanal production during AF: higher temperatures (22 °C versus 18 °C) cause an increase
of the ethanal content during the first days of fermentation; after having reached 6–7% of ethanal, the effect is inverted.
The influence of turbidity is less important, and it's synergic with the effect of temperature. Oxygen has a detrimental effect
on the production of ethanal only at the beginning of the AF, while later, in presence of ethanol, it promotes it through
a chemical way. 相似文献
127.
Anna Stainer Paola Faverio Sara Busnelli Martina Catalano Matteo Della Zoppa Almerico Marruchella Alberto Pesci Fabrizio Luppi 《International journal of molecular sciences》2021,22(12)
Idiopathic pulmonary fibrosis (IPF), the most lethal form of interstitial pneumonia of unknown cause, is associated with a specific radiological and histopathological pattern (the so-called “usual interstitial pneumonia” pattern) and has a median survival estimated to be between 3 and 5 years after diagnosis. However, evidence shows that IPF has different clinical phenotypes, which are characterized by a variable disease course over time. At present, the natural history of IPF is unpredictable for individual patients, although some genetic factors and circulating biomarkers have been associated with different prognoses. Since in its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. Two drugs, pirfenidone and nintedanib, have been shown to modify the disease course by slowing down the decline in lung function. It is also known that 5–10% of the IPF patients may be affected by episodes of acute and often fatal decline. The acute worsening of disease is sometimes attributed to identifiable conditions, such as pneumonia or heart failure; but many of these events occur without an identifiable cause. These idiopathic acute worsenings are termed acute exacerbations of IPF. To date, clinical biomarkers, diagnostic, prognostic, and theranostic, are not well characterized. However, they could become useful tools helping facilitate diagnoses, monitoring disease progression and treatment efficacy. The aim of this review is to cover molecular mechanisms underlying IPF and research into new clinical biomarkers, to be utilized in diagnosis and prognosis, even in patients treated with antifibrotic drugs. 相似文献
128.
129.
A partnership has been developed linking the United States Military Academy and Special People in the Northeast, a non-profit agency for the mentally and physically handicapped children and adults based in Philadelphia. The present work documents a student design team's design and construction of a ticket-tearing device for a young man in the advanced stages of cerebral palsy and concludes with an evaluation of the entire process. 相似文献
130.
Enrico Bellandi Angelo Claudio Nale Massimo Caniatti 《Microelectronic Engineering》2008,85(12):2406-2410
The physical and structural evolution of alumina films deposited by ALCVD annealed at high temperatures in N2 has been studied.Low temperature post deposition treatments in NH3 (PDN) have been performed to evaluate the impact of nitrogen incorporation in the alumina film on its thermal stability. Thermal evolution has been studied by deep UV spectroscopic ellipsometry and grazing X-ray reflectance techniques. AFM measurements were also performed to confirm and complete the ellipsometric and GXR analysis.The change of the crystalline structure was detected by ellipsometry by the different UV refractive index, while the GXR provided a unique thickness evaluation.It was therefore possible to determine the layer densification after the thermal treatment and the impact of the PDN on the transition temperature. 相似文献