全文获取类型
收费全文 | 1760篇 |
免费 | 10篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 96篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 6篇 |
矿业工程 | 2篇 |
能源动力 | 16篇 |
轻工业 | 99篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 18篇 |
一般工业技术 | 49篇 |
冶金工业 | 1418篇 |
原子能技术 | 4篇 |
自动化技术 | 34篇 |
出版年
2023年 | 6篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2017年 | 5篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 12篇 |
2009年 | 24篇 |
2008年 | 12篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 21篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 6篇 |
1999年 | 44篇 |
1998年 | 464篇 |
1997年 | 244篇 |
1996年 | 166篇 |
1995年 | 75篇 |
1994年 | 62篇 |
1993年 | 94篇 |
1992年 | 11篇 |
1991年 | 21篇 |
1990年 | 26篇 |
1989年 | 25篇 |
1988年 | 18篇 |
1987年 | 25篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1977年 | 18篇 |
1976年 | 69篇 |
1974年 | 8篇 |
1973年 | 12篇 |
1970年 | 7篇 |
1969年 | 7篇 |
1968年 | 5篇 |
1967年 | 7篇 |
1966年 | 5篇 |
1961年 | 4篇 |
1960年 | 5篇 |
1958年 | 7篇 |
排序方式: 共有1770条查询结果,搜索用时 31 毫秒
1.
Ole Wiborg Martin O'Connell Richard Thiele Martin Wichert Gunther Kolb 《化学工程与技术》2015,38(8):1308-1314
Many critical issues need to be addressed when microstructured reactors are manufactured in large unit volumes. The most crucial of these are cost, ease of production, and reliability. The lack of breakthrough manufacturing technology to provide high‐efficiency, low‐cost, high‐precision plates is a hindrance to the early market implementation of systems requiring metallic microstructured plates. This contribution focuses on the development and optimization of a combined embossing and bending tool for the quick and continuous manufacture of easily machined plates. 相似文献
2.
LC Niessen 《Canadian Metallurgical Quarterly》1993,53(2):115-118
In the past 5 years we have discovered 8 boys and 3 girls who suffer from fructose-1,6-bisphosphatase deficiency. Although they all showed the typical symptoms of the deficiency such as frequent vomiting, hypoglycemia, lactic acidosis, and hepatomegaly, the age at diagnosis varied from 2 months to 4 years. All the boys revealed the deficient enzyme activity in leukocytes but none of the girls. The liver biopsy was investigated in six patients to confirm the diagnosis. These results suggest the existence of tissue-specific isoenzymes for fructose-1,6-bisphosphatase possibly with a different gene origin. 相似文献
3.
NF Saba JD Sweeney LC Penn JC Lawton RL Yankee CH Huang MS Schanfield 《Canadian Metallurgical Quarterly》1997,37(3):321-324
PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis. 相似文献
4.
Current cementing techniques of distal plugging, pulsatile water cleaning of the canal, and retrograde filling with PMMA in a low-viscous state prepared using porosity reduction techniques and then pressurized have been shown to give excellent results at 10 or more years after operation. However, physical and aging characteristics of PMMA do not guarantee that those results will hold up in the 20- to 30-year time frame. Fifteen-year experience with bony ingrowth systems indicate the development of a durable interface without PMMA, although the interface does appear more vulnerable to attack by the biologic reaction to HMWPE debris. Bone remodeling appears more favorable around proximally fixed bone ingrowth prostheses than around distally fixed prostheses. Softening of the physical characteristics of the stem tip may reduce the incidence of thigh pain. Patients with high activity potential and a life expectancy of greater than 25 years should be strongly considered for a proximally fixed bone ingrowth or ongrowth prosthesis. 相似文献
5.
The development of the temporomandibular joint: a review with regard to the lateral pterygoid muscle
LC Naidoo 《Canadian Metallurgical Quarterly》1993,48(4):189-194
This review sets out to explore the relationship between the lateral pterygoid muscle and the meniscus. It examines the embryological evidence to explain the controversy surrounding the apparent morphological discrepancy in the attachment of the lateral pterygoid muscle to the meniscus. It shows that the contribution of the lateral pterygoid muscle to the formation of the meniscus remains in dispute. Morphogenetic studies have not been able to support either one or other viewpoint and no direct conclusions can therefore be made on the embryology of the temporomandibular joint. 相似文献
6.
Elements of the lactose operon were used to study parameters affecting gene expression in cultured cells and transgenic animals. A Lac repressor protein containing a nuclear transport signal was shown to inhibit expression of a reporter gene by interacting with lac operator sequences. In cultured cells, operator sequence, operator placement and induction parameters were all shown to be important for obtaining tight repression of a reporter gene followed by high level expression upon induction. Induction levels were also dependent on the reporter gene, with the luciferase gene yielding higher induction levels than the chloramphenicol acetyltransferase gene. In transgenic animals, the lacI mRNA was not detected in the C57BL/6 mouse strain until the animal was exposed to a demethylating agent. After 5-azacytidine treatment, expression of lacI mRNA was detected in the brain, heart, kidney, lung and ovary. In the FVB transgenic mouse strain, expression of lacI mRNA was detected without 5-azacytidine treatment in the kidney, liver, lung, and testes. Preliminary experiments with double transgenic animals containing both lacI and operator/luciferase transgenes showed a decrease in luciferase expression compared to the luciferase-only animals in both tissue extracts and transgenic fetal primary cultures, although IPTG induction was not achieved in these animals or primary cultures. The applicability and challenges of the system for regulation of gene expression are discussed. 相似文献
7.
Rats given medial frontal lesions on Postnatal Day 1 or Day 10 were trained on the Morris water task on Days 19–21 or Days 56–58. The operated groups were equally impaired at the water task on Days 19–21, but the Day 10 rats had recovered by 56 days. Dendritic arborization and spine density were analyzed in parietal layer II–III pyramidal cells. At Day 60, but not at Day 22, the Day 10 animals had more dendritic spines per unit dendritic length than did the controls or Day 1 rats. Thus, there was functional recovery rather than sparing after frontal lesions at 10 days, and the recovery was correlated with an increase in dendritic spines. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Cypriano G da Trindade Neto Ana LP Fernandes Ana IB Santos Waldenice A Morais Marcos VM Navarro Tereza NC Dantas Mrcia R Pereira Jos LC Fonseca 《Polymer International》2005,54(4):659-666
Complexation of chitosan in aqueous solutions by low molecular weight electrolytes is one of the simplest methods for the preparation of aqueous chitosan dispersions. In this work, the influence of storage time, sulfate concentration, method of preparation and surfactant content on some properties of the resultant chitosan dispersions (turbidity, viscosity and zeta potential) was analyzed. Turbidimetry was adequate to monitor the formation of particles, while viscometry was suitable to monitor changes in the dispersing phase. An analysis of the properties of these systems, mainly in terms of particle–particle and macromolecule–macromolecule interactions was carried out. Copyright © 2004 Society of Chemical Industry 相似文献
9.
10.
Heart transplant patients take several medications that could affect their periodontal health. Gingival overgrowth associated with cyclosporin (immunosuppressant agent) and nifedipine (calcium channel blocker) is well documented. Candidal infections often develop because of immune suppression. This report describes the clinical and histopathological changes in the gingival tissues of a heart transplant patient and their management. The gingival tissues exhibited pronounced enlargement. The gingivae were lobulated, and the surface of the lobulations was pebbly and granular. Biopsies showed lobules of fibrous connective tissue covered by stratified squamous epithelium. The outer surfaces were dotted with numerous smaller papillations. Candidal hyphae were present in the superficial layers of the epithelium. The extensive papillary lesions appear to be related to candidiasis and constitute a condition which is best designated as papillary stomatitis. Hyperplastic gingival tissues were excised, and the patient was placed on periodic maintenance. One-year postoperative follow-up showed minor gingival growth. 相似文献