全文获取类型
收费全文 | 1352篇 |
免费 | 30篇 |
专业分类
电工技术 | 24篇 |
综合类 | 1篇 |
化学工业 | 257篇 |
金属工艺 | 14篇 |
机械仪表 | 19篇 |
建筑科学 | 56篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 136篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 54篇 |
一般工业技术 | 165篇 |
冶金工业 | 483篇 |
原子能技术 | 5篇 |
自动化技术 | 140篇 |
出版年
2022年 | 15篇 |
2021年 | 20篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 25篇 |
2016年 | 18篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 35篇 |
2011年 | 59篇 |
2010年 | 51篇 |
2009年 | 43篇 |
2008年 | 50篇 |
2007年 | 61篇 |
2006年 | 32篇 |
2005年 | 44篇 |
2004年 | 27篇 |
2003年 | 28篇 |
2002年 | 22篇 |
2001年 | 20篇 |
2000年 | 30篇 |
1999年 | 30篇 |
1998年 | 153篇 |
1997年 | 83篇 |
1996年 | 53篇 |
1995年 | 54篇 |
1994年 | 39篇 |
1993年 | 31篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 19篇 |
1989年 | 22篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 16篇 |
1976年 | 41篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1925年 | 4篇 |
排序方式: 共有1382条查询结果,搜索用时 78 毫秒
1.
David L. Wood Jeffrey D. Quass Jianlin Li Shabbir Ahmed David Ventola Claus Daniel 《Drying Technology》2018,36(2):234-244
Processing lithium-ion battery (LIB) electrode dispersions with water as the solvent during primary drying offers many advantages over N-methylpyrrolidone (NMP). An in-depth analysis of the comparative drying costs of LIB electrodes is discussed for both NMP- and water-based dispersion processing in terms of battery pack $/kWh. Electrode coating manufacturing and capital equipment cost savings are compared for water vs. conventional NMP organic solvent processing. A major finding of this work is that the total electrode manufacturing costs, whether water- or NMP-based, contribute about 8–9% of the total pack cost. However, it was found that up to a 2?×?reduction in electrode processing (drying and solvent recovery) cost can be expected along with a $3–6?M savings in associated plant capital equipment (for a plant producing 100,000 10-kWh Plug-in Hybrid Electric Vehicle (PHEV) batteries) using water as the electrode solvent. This paper shows a different perspective in that the most important benefits of aqueous electrode processing actually revolve around capital equipment savings and environmental stewardship and not processing cost savings. 相似文献
2.
3.
Two Caribbean hair sheep breeds, the St. Croix (SC) and Barbados Blackbelly (BB), are found in the United States, and the SC has led to the development of the Katahdin (K), a synthetic breed of hair sheep. These breeds have mature ewe BW ranging from 32 to 54 kg (for BB and SC) and from 55 to 73 kg (K). Hair sheep and hair sheep crosses have lower rectal temperatures and respiration rates than wool breeds and a lower DMI and water intake. There are indications of increased resistance to internal parasites in hair sheep. Although hair sheep are seasonal breeders under U.S. photoperiodic conditions, they tend to perform better under accelerated lambing systems than traditional wool breeds. Fertility, prolificacy, and lamb survival is high in BB and SC, but hair x wool crossbred ewes tend to have a higher level of fertility than hair and wool parent breeds. Ewe productivity is also higher in hair x wool crosses than in wool crosses, particularly when adjusted for ewe BW or under accelerated lambing systems. Hair sheep have a lower ADG and intake of high-energy diets, as well as a lower gain/feed ratio, than wool breeds. Growth rates tend to be higher in SC than in BB. Differences in carcass characteristics are inconsistent between hair and wool breeds. Production characteristics of hair sheep, particularly hair x wool crosses, make them suitable for low-input, sustainable production systems that do not require high growth rates and large carcasses. There is a need to preserve the existing U.S. hair sheep germplasm base in support of such systems. 相似文献
4.
We report two patients with ileal carcinoid tumours which were associated with polyps due to mucosal granulation tissue proliferation. In both cases the tumours had extensively infiltrated the small bowel wall and mesentery, and one had hepatic metastases. The mucosal surface of each specimen showed numerous, pale brown, sessile polyps which were restricted to the intestinal segment involved by carcinoid tumour, although not always closely related to neoplastic cells. The polyps were formed by the proliferation of capillaries, smooth muscle cells and myofibroblasts as demonstrated by immunohistochemistry and electronmicroscopy. 相似文献
5.
Claus Bahlmann Author Vitae 《Pattern recognition》2006,39(1):115-125
The selection of valuable features is crucial in pattern recognition. In this paper we deal with the issue that part of features originate from directional instead of common linear data. Both for directional and linear data a theory for a statistical modeling exists. However, none of these theories gives an integrated solution to problems, where linear and directional variables are to be combined in a single, multivariate probability density function. We describe a general approach for a unified statistical modeling, given the constraint that variances of the circular variables are small. The method is practically evaluated in the context of our online handwriting recognition system frog on hand and the so-called tangent slope angle feature. Recognition results are compared with two alternative modeling approaches. The proposed solution gives significant improvements in recognition accuracy, computational speed and memory requirements. 相似文献
6.
RM Bionta G Blewitt CB Bratton D Casper A Ciocio R Claus M Crouch ST Dye S Errede GW Foster W Gajewski KS Ganezer M Goldhaber TJ Haines TW Jones D Kielczewska WR Kropp JG Learned JM LoSecco J Matthews HS Park LR Price F Reines J Schulz S Seidel E Shumard D Sinclair HW Sobel JL Stone L Sulak R Svoboda G Thornton van der Velde JC C Wuest 《Canadian Metallurgical Quarterly》1987,36(1):30-36
7.
8.
9.
10.
JM Cummings RO Parra JA Boullier 《Canadian Metallurgical Quarterly》1995,45(3):414-8; discussion 418-20
OBJECTIVES: An evolving technology for the treatment of bladder outlet obstruction due to benign prostatic hyperplasia (BPH) is the use of the side-firing neodymium: yttrium-aluminum-garnet (Nd:YAG) laser to achieve prostatic tissue ablation. The purpose of this study was to determine the short-term efficacy of this procedure in both an objective and subjective manner. METHODS: We examined this technique by carefully evaluating our first 25 men undergoing the procedure. Each patient was subjected to careful symptom score analysis using the American Urological Association symptom index and multichannel urodynamics, including pressure-flow studies both preoperatively and at 3 months postoperatively. RESULTS: At the 3-month follow-up, symptom scores improved from a preoperative mean of 11.4 to 7.2 and the mean maximum flow rate improved from 6.1 to 14.5 cc/s. These are both significant at P < 0.001. Statistically similar improvement was seen in detrusor pressure at opening and at maximum flow. Eighty percent of the men studied had at least a 50% reduction in symptom score and a 50% improvement in flow rate. CONCLUSIONS: We conclude that laser prostatectomy is a promising minimally invasive treatment for bladder outlet obstruction secondary to BPH and deserves further evaluation at longer terms of follow-up. 相似文献