全文获取类型
收费全文 | 4450篇 |
免费 | 140篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 27篇 |
综合类 | 5篇 |
化学工业 | 790篇 |
金属工艺 | 40篇 |
机械仪表 | 52篇 |
建筑科学 | 170篇 |
矿业工程 | 29篇 |
能源动力 | 44篇 |
轻工业 | 496篇 |
水利工程 | 44篇 |
石油天然气 | 34篇 |
无线电 | 188篇 |
一般工业技术 | 534篇 |
冶金工业 | 1584篇 |
原子能技术 | 13篇 |
自动化技术 | 545篇 |
出版年
2023年 | 21篇 |
2022年 | 75篇 |
2021年 | 92篇 |
2020年 | 56篇 |
2019年 | 53篇 |
2018年 | 79篇 |
2017年 | 77篇 |
2016年 | 76篇 |
2015年 | 69篇 |
2014年 | 94篇 |
2013年 | 227篇 |
2012年 | 169篇 |
2011年 | 260篇 |
2010年 | 160篇 |
2009年 | 191篇 |
2008年 | 187篇 |
2007年 | 208篇 |
2006年 | 169篇 |
2005年 | 163篇 |
2004年 | 140篇 |
2003年 | 134篇 |
2002年 | 122篇 |
2001年 | 73篇 |
2000年 | 84篇 |
1999年 | 86篇 |
1998年 | 67篇 |
1997年 | 97篇 |
1996年 | 94篇 |
1995年 | 75篇 |
1994年 | 76篇 |
1993年 | 93篇 |
1992年 | 88篇 |
1991年 | 40篇 |
1990年 | 73篇 |
1989年 | 76篇 |
1988年 | 54篇 |
1987年 | 67篇 |
1986年 | 69篇 |
1985年 | 70篇 |
1984年 | 45篇 |
1983年 | 49篇 |
1982年 | 43篇 |
1981年 | 41篇 |
1980年 | 32篇 |
1979年 | 35篇 |
1977年 | 27篇 |
1976年 | 18篇 |
1975年 | 24篇 |
1974年 | 17篇 |
1973年 | 19篇 |
排序方式: 共有4595条查询结果,搜索用时 15 毫秒
51.
Mary S Patil GV Kulkarni AV Kulkarni MJ Joshi SR Mehendale SS Giri AP 《Proteomics. Clinical applications》2012,6(1-2):79-90
The coevolution of genomics and proteomics has led to advancements in the field of diagnosis and molecular mechanisms of disease. Proteomics is now stepping into the field of obstetrics, where early diagnosis of pregnancy complication such as preeclampsia (PE) is imperative. PE is a multifactorial disease characterized by hypertension with proteinuria, which is a leading cause of maternal and neonatal morbidity and mortality occurring in 5-7% of pregnancies worldwide. This review discusses the probable molecular mechanisms that lead to PE and summarizes the proteomics research carried out in understanding the pathogenicity of PE, and for identifying the candidate biomarker for diagnosis of the disease. 相似文献
52.
53.
Microsystem Technologies - Tuberculosis is a contagious disease caused by the bacteria, Mycobacterium Tuberculosis. Early detection of TB is vital to increase the chances of cure. In this paper, a... 相似文献
54.
Isenberg P Fisher D Paul SA Morris MR Inkpen K Czerwinski M 《IEEE transactions on visualization and computer graphics》2012,18(5):689-702
Co-located collaboration can be extremely valuable during complex visual analytics tasks. We present an exploratory study of a system designed to support collaborative visual analysis tasks on a digital tabletop display. Fifteen participant pairs employed Cambiera, a visual analytics system, to solve a problem involving 240 digital documents. Our analysis, supported by observations, system logs, questionnaires, and interview data, explores how pairs approached the problem around the table. We contribute a unique, rich understanding of how users worked together around the table and identify eight types of collaboration styles that can be used to identify how closely people work together while problem solving. We show how the closeness of teams’ collaboration and communication influenced how they performed on the task overall. We further discuss the role of the tabletop for visual analytics tasks and derive design implications for future co-located collaborative tabletop problem solving systems. 相似文献
55.
C?t?lin Bu?neag Dana Piciu 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(10):1639-1655
The spectrum of a residuated lattice L is the set Spec(L) of all prime i-filters. It is well known that Spec(L) can be endowed with the spectral topology. The main scope of this paper is to introduce and study another topology on Spec(L),?the so called stable topology, which turns out to be coarser than the spectral one. With this and in view, we introduce the notions of pure i-filter for a residuated lattice and the notion of normal residuated lattice. So, we generalize to case of residuated lattice some results relative to MV-algebras (Belluce and Sessa in Quaest Math 23:269–277, 2000; Cavaccini et?al. in Math Japonica 45(2):303–310, 1997) or BL-algebras (Eslami and Haghani in Kybernetika 45:491–506, 2009; Leustean in Central Eur J Math 1(3): 382–397, 2003; Turunen and Sessa in Mult-Valued Log 6(1–2):229–249, 2001). 相似文献
56.
Fish oils containing different levels of polymers of triacylglycerols formed during autoxidation were incubated with pancreatic
lipase to establish whether these polymers are substrates for lipase hydrolysis. With oils containing low amounts (less than
4%) of triacylglycerol polymers as substrates, both triacylglycerols and polymers of triacylglycerols were almost completely
hydrolyzed, and fatty acid monomers and monoacylglycerols were the major lipid products. Under the same incubation conditions,
some triacylglycerols remained intact when highly oxidized oils containing 20 or 30% triacylglycerol polymers were the substrate.
The fatty acid composition of these residual triacylglycerols was almost identical to that of triacylglycerols present at
the start of the assay. When fish oil containing 30% triacylglycerol polymers was incubated with the lipase, the component
triacylglycerols and polymers of triacylglycerols were hydrolyzed at similar rates, and fatty acid dimers were detected as
a product. It is concluded that the high molecular weight polymers of triacylglycerols present in oxidized fish oils can be
hydrolyzed by pancreatic lipasein vitro. 相似文献
57.
Summary Asparagus seed, Mary Washington variety, was found to contain 14.7% of glyceride oil having iodine value 135.1, saponification
value 185.5, and unsaponifiable matter 1.46%. The oil was converted to methyl esters, and the mixed esters were separated
by fractional distillation and low-temperature crystallization. The acids were identified by chemical and physical methods.
The % composition of the fatty acids is estimated from the data as follows: palmitic 3, linoleic 57, oleic 27, stearic 2,
eicosenoic 1.5, arachidic 0.6, undetermined 9. The oil is somewhat similar to corn oil in composition. It has at least 2%
of acids of the C20 series, which have not been reported previously in this plant family (Liliaceae).
Presented at the meeting of the American Oil Chemists' Society, Philadelphia, Pa., October 10–12, 1955. Issued as N.R.C. No.
4426. 相似文献
58.
Dana G. Miloaga Hazel‐Ann A. Hosein Manjusri Misra Lawrence T. Drzal 《应用聚合物科学杂志》2007,106(4):2548-2558
Poly(3‐hydroxybutyrate) (PHB) has been shown to be efficiently nucleated by exfoliated graphite nanoplatelets (xGnP). The nucleating effect of xGnP was investigated using differential scanning calorimetry, optical microscopy and atomic force microscopy. Nonisothermal crystallization of PHB from the melt required lower activation energies for PHB containing 1 wt % and 3 wt % xGnP (?214 and ?102 kJ/mol respectively) than for pure PHB (?60 kJ/mol). A kinetic study of the PHB/xGnP crystallization employing a modified form of the Avrami equation revealed that the presence of xGnP increased the PHB crystallization temperature, as well as the crystallization rates, and generated smaller and more numerous spherulites. Optical microscopy and atomic force microscopy confirmed the incorporation of xGnP into the lamellar structure of the PHB spherulites and provided insight into the influence of xGnP on spherulite size and lamellae thickness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
59.
60.
Mary E. Mossey Yubin Xi Shayne K. McConomy Johnell O. Brooks Patrick J. Rosopa Paul J. Venhovens 《Applied ergonomics》2014
While much research exists on occupant packaging both proprietary and in the literature, more detailed research regarding user preferences for subjective ratings of steering wheel designs is sparse in published literature. This study aimed to explore the driver interactions with production steering wheels in four vehicles by using anthropometric data, driver hand placement, and driver grip design preferences for Generation-Y and Baby Boomers. In this study, participants selected their preferred grip diameter, responded to a series of questions about the steering wheel grip as they sat in four vehicles, and rank ordered their preferred grip design. Thirty-two male participants (16 Baby Boomers between ages 47 and 65 and 16 Generation-Y between ages 18 and 29) participated in the study. Drivers demonstrated different gripping behavior between vehicles and between groups. Recommendations for future work in steering wheel grip design and naturalistic driver hand positioning are discussed. 相似文献