全文获取类型
收费全文 | 1472篇 |
免费 | 16篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 158篇 |
金属工艺 | 21篇 |
机械仪表 | 14篇 |
建筑科学 | 55篇 |
矿业工程 | 9篇 |
能源动力 | 16篇 |
轻工业 | 138篇 |
水利工程 | 18篇 |
石油天然气 | 1篇 |
无线电 | 52篇 |
一般工业技术 | 99篇 |
冶金工业 | 816篇 |
原子能技术 | 2篇 |
自动化技术 | 88篇 |
出版年
2023年 | 8篇 |
2022年 | 8篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 49篇 |
2012年 | 22篇 |
2011年 | 24篇 |
2010年 | 32篇 |
2009年 | 20篇 |
2008年 | 36篇 |
2007年 | 35篇 |
2006年 | 24篇 |
2005年 | 28篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 30篇 |
1998年 | 219篇 |
1997年 | 137篇 |
1996年 | 96篇 |
1995年 | 57篇 |
1994年 | 51篇 |
1993年 | 57篇 |
1992年 | 17篇 |
1991年 | 16篇 |
1990年 | 22篇 |
1989年 | 31篇 |
1988年 | 33篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 25篇 |
1984年 | 13篇 |
1983年 | 18篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 44篇 |
1976年 | 50篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1966年 | 5篇 |
1955年 | 5篇 |
排序方式: 共有1490条查询结果,搜索用时 15 毫秒
131.
Grape seed flour (GSF) from grape pomace, a waste product generated during winemaking, was explored for use in bread production due to its potential health benefits. This study evaluated the consumer acceptance and physical properties of bread, including total phenolic content (TPC), made with varying levels of GSF. Dough and breads were prepared using different levels of replacement of hard red spring wheat flour (HRS) with GSF (0 to 10 g GSF/100 g HRS) and stored for 0, 2, or 6 wk at -20 °C. Replacement of 10 g GSF/100 g HRS increased the bread TPC from 0.064 mg tannic acid/g dry weight to 4.25 mg tannic acid/g dry weight. Consumer acceptance and instrumental analyses were used to investigate changes in sensory and texture properties due to GSF replacement. Replacement above 5 g GSF/100 g HRS decreased the loaf brightness and volume, with an increase in the bread hardness and porosity. Generally, breads containing ≥ 7.5 g GSF/100 g HRS were characterized by lower consumer acceptance. A reduction in overall and bitterness acceptance was observed in bread at 10 g GSF/100 g HRS, with decreased acceptance of astringency and sweetness at 7.5 and 10 g GSF/100 g HRS. Based on these results, the replacement of 5 g GSF/100 g HRS is recommended for the production of fortified breads with acceptable physical and sensory properties and high TPC activity compared to refined bread. PRACTICAL APPLICATIONS: This study shows that grape seed flour (GSF) can be used to replace hard red spring wheat flour (HRS) in bread production, with moderate impact on the physical and sensory properties of the bread. Replacement of up to 10 g GSF/100 g HRS significantly decreased overall consumer acceptance of the bread, with lower consumer acceptance of sweetness and astringency at 7.5 and 10 g GSF/100 g HRS. Thus, a replacement value of 5 g GSF/100 g HRS is recommended for the production of fortified breads. 相似文献
132.
133.
134.
135.
OBJECTIVE: This article brings to the present earlier bibliographies of books written by former mental patients. These books provide an inside view of mental disorder that can be useful in teaching, public education, theory, and research, and they have played a catalyzing role in mental health reform and in theory development. METHOD: The authors list seven anthologies and 48 autobiographies of former patients published since 1980 and introduce a classification system intended to increase the research value of this important archive. RESULTS: Recent books of this genre show more individuals with a mood disorder and more therapists and more women as authors. CONCLUSIONS: The research potential of these books suggests the value of an electronic database for classifying and retrieving the information they contain. 相似文献
136.
CG Jones RS Ostfeld MP Richard EM Schauber JO Wolff 《Canadian Metallurgical Quarterly》1998,279(5353):1023-1026
In eastern U.S. oak forests, defoliation by gypsy moths and the risk of Lyme disease are determined by interactions among acorns, white-footed mice, moths, deer, and ticks. Experimental removal of mice, which eat moth pupae, demonstrated that moth outbreaks are caused by reductions in mouse density that occur when there are no acorns. Experimental acorn addition increased mouse density. Acorn addition also increased densities of black-legged ticks, evidently by attracting deer, which are key tick hosts. Mice are primarily responsible for infecting ticks with the Lyme disease agent. The results have important implications for predicting and managing forest health and human health. 相似文献
137.
EC Griffith Z Su S Niwayama CA Ramsay YH Chang JO Liu 《Canadian Metallurgical Quarterly》1998,95(26):15183-15188
Angiogenesis inhibitors are a novel class of promising therapeutic agents for treating cancer and other human diseases. Fumagillin and ovalicin compose a class of structurally related natural products that potently inhibit angiogenesis by blocking endothelial cell proliferation. A synthetic analog of fumagillin, TNP-470, is currently undergoing clinical trials for treatment of a variety of cancers. A common target for fumagillin and ovalicin recently was identified as the type 2 methionine aminopeptidase (MetAP2). These natural products bind MetAP2 covalently, inhibiting its enzymatic activity. The specificity of this binding is underscored by the lack of inhibition of the closely related type 1 enzyme, MetAP1. The molecular basis of the high affinity and specificity of these inhibitors for MetAP2 has remained undiscovered. To determine the structural elements of these inhibitors and MetAP2 that are involved in this interaction, we synthesized fumagillin analogs in which each of the potentially reactive epoxide groups was removed either individually or in combination. We found that the ring epoxide in fumagillin is involved in the covalent modification of MetAP2, whereas the side chain epoxide group is dispensable. By using a fumagillin analog tagged with fluorescein, His-231 in MetAP2 was identified as the residue that is covalently modified by fumagillin. Site-directed mutagenesis of His-231 demonstrated its importance for the catalytic activity of MetAP2 and confirmed that the same residue is covalently modified by fumagillin. These results, in agreement with a recent structural study, suggest that fumagillin and ovalicin inhibit MetAP2 by irreversible blockage of the active site. 相似文献
138.
JO Nielsen 《Canadian Metallurgical Quarterly》1998,113(9):287-289
The most important preventive measures against accidental HIV infection in health care are the education of personnel and the observance of routine procedures in everyday work. In this way, the accidental infection rate can be reduced by more than 50 per cent. Consistent registration of the causes of accidental infection can further reduce work-related risks. In January, the Danish authorities issued guidelines for the use of antiviral chemoprophylaxis against HIV infection following occupational exposure. A four-week course of triple-drug anti-retroviral prophylaxis is recommended to prevent HIV infection in causes of needle-stick or other penetration injuries. 相似文献
139.
M Robert JO Roux F Bourelly AM Boularan J Guiter L Monnier 《Canadian Metallurgical Quarterly》1994,74(3):294-297
OBJECTIVE: To evaluate the circadian fluctuations in the risk of urinary calcium oxalate stone formation with regard to critical periods of crystallization. PATIENTS AND METHODS: Over a given time period, the Tiselius index depends on urine volume and urinary excretion of oxalate, calcium, citrate and magnesium. This crystallization potential was evaluated during three successive periods spread over 24 h for 25 recurrent stone-formers aged 16-76 years (mean 50) and 25 control subjects aged 27-71 years (mean 44). RESULTS: There was no significant difference in the value of the Tiselius index for all equivalent time periods in both groups of patients. The minimum value was recorded in the afternoon and the circadian pattern of the index illustrated the predominant importance of urinary output in its determination. Morning urinary concentrations and excretions of citrate, and nocturnal levels of magnesium were significantly higher in the stone-formers when compared with the control subjects. CONCLUSION: The lithogenic risk for calcium oxalate stones was maximal at the end of the night or during the early morning, when urinary output was minimal. This circadian study revealed abnormalities that are not apparent from non-fractionated 24 h urine samples, and which were potentially relevant to therapy. 相似文献
140.
Z Mourelatos JO Gonatas LM Nycum NK Gonatas JA Biegel 《Canadian Metallurgical Quarterly》1995,28(2):354-355