全文获取类型
收费全文 | 7542篇 |
免费 | 61篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 47篇 |
化学工业 | 396篇 |
金属工艺 | 70篇 |
机械仪表 | 57篇 |
建筑科学 | 125篇 |
矿业工程 | 16篇 |
能源动力 | 43篇 |
轻工业 | 296篇 |
水利工程 | 28篇 |
石油天然气 | 7篇 |
无线电 | 295篇 |
一般工业技术 | 452篇 |
冶金工业 | 5354篇 |
原子能技术 | 19篇 |
自动化技术 | 402篇 |
出版年
2021年 | 30篇 |
2019年 | 20篇 |
2018年 | 25篇 |
2017年 | 32篇 |
2016年 | 17篇 |
2015年 | 32篇 |
2014年 | 58篇 |
2013年 | 152篇 |
2012年 | 103篇 |
2011年 | 104篇 |
2010年 | 57篇 |
2009年 | 62篇 |
2008年 | 89篇 |
2007年 | 107篇 |
2006年 | 104篇 |
2005年 | 74篇 |
2004年 | 81篇 |
2003年 | 96篇 |
2002年 | 74篇 |
2001年 | 57篇 |
2000年 | 54篇 |
1999年 | 212篇 |
1998年 | 1582篇 |
1997年 | 976篇 |
1996年 | 594篇 |
1995年 | 355篇 |
1994年 | 280篇 |
1993年 | 344篇 |
1992年 | 86篇 |
1991年 | 85篇 |
1990年 | 104篇 |
1989年 | 96篇 |
1988年 | 120篇 |
1987年 | 85篇 |
1986年 | 82篇 |
1985年 | 95篇 |
1984年 | 28篇 |
1983年 | 27篇 |
1982年 | 43篇 |
1981年 | 72篇 |
1980年 | 76篇 |
1979年 | 27篇 |
1978年 | 32篇 |
1977年 | 178篇 |
1976年 | 307篇 |
1975年 | 33篇 |
1974年 | 24篇 |
1973年 | 29篇 |
1972年 | 19篇 |
1971年 | 18篇 |
排序方式: 共有7607条查询结果,搜索用时 15 毫秒
1.
Zenan Yu Julian Moore Jean Calderon Lei Zhai Jayan Thomas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(39):5289-5295
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets. 相似文献
2.
3.
4.
MA Molina MJ Romero E Abril I Delgado RM Cano F Garrido JM de Pablos ML Garrido 《Canadian Metallurgical Quarterly》1994,39(4):253-256
INTRODUCTION: Heterozygous beta-thalassemia manifests hematologically with microcytosis, reduced red blood cell hemoglobin concentration and high hemoglobin A2 levels. Almost all molecular alterations are due to point mutations. We attempt to determinate the frequency of that mutations in the Oriental Andalusia Area, and its relationship with the hematological phenotype. PATIENTS AND METHODS: We have studied 45 heterozygous patients. DNA samples were amplified by PCR, using the printers CD7 and HI1. A 16 Kb fragment corresponding to beta globin gene was obtained and analyzed by Dot Blot assay and hybridized with allelic specific oligonucleotide (ASO) probes to detect the 6 more frequent mutations found in the South of Spain. RESULTS: Codon 39 nonsense mutation (31.1%) was the most frequent finding followed by IVS-1 NT 110 (26.7%). The relationship between hematological parameters and molecular mutations concluded that IVS-I NT 6 mutation developed a minimal anemia. DISCUSSION: From the practical point of view, this study indicates that we were able to detect more than 90% of heterozygous beta-tal. with 5 out of 6 ASO probes used in this work. Thus, our data also provides a further implication in prenatal diagnosis. 相似文献
5.
6.
NC Moore 《Canadian Metallurgical Quarterly》1997,86(2):81-82
The nation's health care system is undergoing a period of rapid change that will profoundly affect women's health care services and, ultimately, women's health. Although managed care is quickly becoming the predominant mode of health care delivery in the United States, a new, more consumer-focused, and accountable model known as organized systems of care (OSC) is emerging. OSC development has been driven by large private and public employers seeking to purchase the highest quality health care for the best price. The changes in health care delivery encouraged by these innovative employers will provide women with optimal care and attention, which will in turn help them attract and retain a competitive and productive workforce. 相似文献
7.
BACKGROUND: IgE-mediated hypersensitivity to latex proteins has become a significant clinical problem over the last decade. Nursing and medical staff are at risk because of their occupational exposure to latex. AIMS: To determine the prevalence of type I hypersensitivity to latex allergens in the nursing staff of an Australian hospital. METHODS: A questionnaire which asked about symptoms associated with the use of latex gloves was completed by 140 nurses working in the Alfred Hospital (72 in general medical wards, 68 in intensive care units). Skin prick tests with eluates of five different types of latex glove as well as common aeroallergens (rye pollen and house dust mite) and banana extract were performed. RESULTS: Thirty-one nurses (22%) were skin prick test positive to at least one of the five latex glove eluates. All of these nurses were atopic, having positive skin prick tests to rye pollen or house dust mite. Symptoms of local dryness, itch and erythema associated with glove use were reported by more than half the study group, but not more frequently by those who were skin prick test positive to latex. Urticaria associated with glove use was reported more frequently by those with positive latex skin prick tests (13% vs 4%, p = 0.05). Eighty-seven per cent of the nurses who were latex skin test positive were also positive to banana extract. CONCLUSIONS: IgE-mediated hypersensitivity to latex is common in nurses working in an Australian hospital. Glove associated symptoms were frequently reported, but in most cases the symptoms were more typical of irritant or contact dermatitis rather than type I hypersensitivity reactions. However, the extent of subclinical sensitisation to latex found in this study suggests that symptomatic latex allergy is likely to emerge as an increasing problem for nursing staff in this country. 相似文献
8.
An extensively modified version of MolScript that includes greatly enhanced coloring capabilities 总被引:3,自引:0,他引:3
RM Esnouf 《Canadian Metallurgical Quarterly》1997,15(2):132-4, 112-3
Owing to its flexibility, MolScript has become one of the most widely used programs for generating publication-quality molecular graphics. Integration with the Raster3D package, to allow the production of photorealistic rendered images, has increased its popularity still further. However, this intensive use has shown the need for enhancement of some areas of the program, especially for controlling the coloring of atoms, bonds, and molecules. This work describes a heavily modified version of MolScript that has added syntax for describing complicated coloring schemes and also has new graphics commands. Enhancements include drawing split-bond ball-and-stick models, smoothly varying the color of molecules (color ramping), abrupt color changes within secondary structural units, and the creation of dashed bonds. Making use of these added features is simple because all MolScript syntax is still supported and one typically needs only to add a few control commands. The final section of this article suggests some uses for this modified MolScript and provides illustrative examples. 相似文献
9.
10.
RM Barkin 《Canadian Metallurgical Quarterly》1997,15(2):381-388
A pediatric focus in the emergency department requires an understanding of age-specific parameters of assessment and management. Differential considerations are unique in the pediatric patient reflecting both congenital and acquired conditions. Respiratory problems, meningitis, seizures, and child abuse require careful assessment and aggressive intervention. When approaching the ill child, attention must be directed toward reducing anxiety and pain in the patient. 相似文献