全文获取类型
收费全文 | 2772篇 |
免费 | 158篇 |
国内免费 | 60篇 |
专业分类
电工技术 | 23篇 |
综合类 | 97篇 |
化学工业 | 779篇 |
金属工艺 | 29篇 |
机械仪表 | 38篇 |
建筑科学 | 53篇 |
矿业工程 | 15篇 |
能源动力 | 88篇 |
轻工业 | 449篇 |
水利工程 | 25篇 |
石油天然气 | 29篇 |
无线电 | 85篇 |
一般工业技术 | 139篇 |
冶金工业 | 681篇 |
原子能技术 | 107篇 |
自动化技术 | 353篇 |
出版年
2024年 | 10篇 |
2023年 | 40篇 |
2022年 | 147篇 |
2021年 | 217篇 |
2020年 | 98篇 |
2019年 | 79篇 |
2018年 | 66篇 |
2017年 | 64篇 |
2016年 | 100篇 |
2015年 | 84篇 |
2014年 | 115篇 |
2013年 | 165篇 |
2012年 | 192篇 |
2011年 | 161篇 |
2010年 | 165篇 |
2009年 | 162篇 |
2008年 | 101篇 |
2007年 | 142篇 |
2006年 | 122篇 |
2005年 | 115篇 |
2004年 | 98篇 |
2003年 | 89篇 |
2002年 | 74篇 |
2001年 | 53篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 24篇 |
1997年 | 31篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 13篇 |
1993年 | 18篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 13篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1966年 | 3篇 |
1963年 | 3篇 |
1961年 | 6篇 |
1957年 | 2篇 |
1955年 | 6篇 |
1954年 | 2篇 |
排序方式: 共有2990条查询结果,搜索用时 15 毫秒
101.
IntroductionPlaying an instrument could lead to various disorders and several musicians report problems during their career. As there is no existing one, the aim of this study was to build a comprehensive model of injury prevention and risk factors in musicians by combining literature with interviews of musicians and experts.MethodsThe initial model has been based on literature. This model identified nine categories of risk factors. Then, interviews were conducted with 15 Royal Liverpool Philharmonic Orchestra musicians and 9 experts in musicians’ health to develop the final version.ResultsEighty percent of the RLPO instrumentalists experienced at least once PRMDs in their career. Postural and workload issues were mentioned most frequently. Experts agreed broadly with the initial model and added interesting items that should be taken into account in assessing musicians’ health.DiscussionThis theoretical framework provides perspectives in terms of assessment, treatment and prevention in musicians, whether they are currently suffering from PRMDs or not. 相似文献
102.
Musculoskeletal disorders (MSD) have a high impact on the health of dual role workers (student and work). The aim of this study was to analyse risk factor (active pauses and job position) associated with MSD in postgraduate students, Bogotá 2016. This Cross-sectional study was conducted in a random sample of 304 college graduate students and statistical analysis in SPSS version 24. We found that significant differences between non-performing active pauses and neck symptoms (P = 0.007), not stretching vs neck symptoms [OR = 2.4048 (1.0133–5.707)]; laptop use vs eyes [OR = 2.7132 (1.457–5.0526)], shoulders [OR = 10.6364 (4.9905–22.6697)], elbows (P = 0.04); non-mouse usage vs elbows (P = 0.028), hand-wrist (P = 0.043); non-forearm support vs lower back (P = 0.009). Results suggest association between non-performing active pauses, stretching and neck; use of laptop and eyes, shoulders and left elbow, non-mouse usage and on elbow and hand/right wrist, no forearm support on table and lower back. Symptom changes in the upper and lower limbs were identified. 相似文献
103.
《工程(英文)》2020,6(4):462-467
A number of brain research projects have recently been carried out to study the etiology and mechanisms of psychiatric disorders. Although psychiatric disorders are part of the brain sciences, psychiatrists still diagnose them based on subjective experience rather than by gaining insights into the pathophysiology of the diseases. Therefore, it is urgent to have a clear understanding of the etiology and pathogenesis of major psychiatric diseases, which can help in the development of effective treatments and interventions. Artificial intelligence (AI)-based applications are being quickly developed for psychiatric research and diagnosis, but there is no systematic review that summarizes their applications. For this reason, this study briefly reviews three main brain observation techniques used to study psychiatric disorders—namely, magnetic resonance imaging (MRI), electroencephalography (EEG), and kinesics diagnoses—along with related AI applications and algorithms. Finally, we discuss the challenges, opportunities, and future study directions of AI-based applications. 相似文献
104.
ObjectiveThe objective of this article is to examine the application of MSD prevention practices among nursing staff and to identify organizational factors that may or may not support their application.MethodsWe measured the application of prevention practices and its determinants by means of a questionnaire filled out by 399 nurses and nursing staff in Canada. A qualitative component was conducted with two focus groups in order to validate and enrich the interpretation of the survey results.ResultsResults show that most respondents “often” (4) apply MSD prevention practices in their daily professional tasks. Significant differences were observed based on position, mission of the institution, degree, and training.ConclusionsThe characteristics of the nursing staff (position, training, etc.) and the specificities of the setting must be taken into consideration in MSD prevention interventions for nursing staff. 相似文献
105.
Kimiyoshi Ichida Yoshihiro Amaya Ken Okamoto Takeshi Nishino 《International journal of molecular sciences》2012,13(11):15475-15495
Xanthine oxidoreductase (XOR) catalyzes the conversion of hypoxanthine to xanthine and xanthine to uric acid with concomitant reduction of either NAD+ or O2. The enzyme is a target of drugs to treat hyperuricemia, gout and reactive oxygen-related diseases. Human diseases associated with genetically determined dysfunction of XOR are termed xanthinuria, because of the excretion of xanthine in urine. Xanthinuria is classified into two subtypes, type I and type II. Type I xanthinuria involves XOR deficiency due to genetic defect of XOR, whereas type II xanthinuria involves dual deficiency of XOR and aldehyde oxidase (AO, a molybdoflavo enzyme similar to XOR) due to genetic defect in the molybdenum cofactor sulfurase. Molybdenum cofactor deficiency is associated with triple deficiency of XOR, AO and sulfite oxidase, due to defective synthesis of molybdopterin, which is a precursor of molybdenum cofactor for all three enzymes. The present review focuses on mutation or chemical modification studies of mammalian XOR, as well as on XOR mutations identified in humans, aimed at understanding the reaction mechanism of XOR and the relevance of mutated XORs as models to estimate the possible side effects of clinical application of XOR inhibitors. 相似文献
106.
107.
Protein therapy exhibits several advantages over small molecule drugs and is increasingly being developed for the treatment of disorders ranging from single enzyme deficiencies to cancer. Cell-penetrating peptides (CPPs), a group of small peptides capable of promoting transport of molecular cargo across the plasma membrane, have become important tools in promoting the cellular uptake of exogenously delivered proteins. Although the molecular mechanisms of uptake are not firmly established, CPPs have been empirically shown to promote uptake of various molecules, including large proteins over 100 kiloDaltons (kDa). Recombinant proteins that include a CPP tag to promote intracellular delivery show promise as therapeutic agents with encouraging success rates in both animal and human trials. This review highlights recent advances in protein-CPP therapy and discusses optimization strategies and potential detrimental effects. 相似文献
108.
《分离科学与技术》2012,47(16):2587-2595
Printed circuit board (PCB) is the essential part of electronic devices and has an important source of base and precious metals with high economic potential. In this study, selective leaching of gold from PCB was performed in an iodine-hydrogen peroxide (I2-H2O2) solution system. The effects of different parameters such as iodine concentrations, H2O2 concentrations and solids-% on the gold leaching dynamics were investigated. The results show that increasing solids-% has a negative influence on the gold leaching. However, gold recovery from the e-wastes in a solution containing 3% iodine, 1% H2O2 with solids-% of 15% resulted with 100% recovery among all leaching tests. 相似文献
109.
The effect of microwave heating on the iodine-catalyzed acetylation of rubberwood with acetic anhydride has been investigated. Microwave radiation was used as the heating source for modifying specimens saturated with acetic anhydride in bulk solution (excess of reagent) and impregnated specimens (limited supply of anhydride). Extent of modification of wood was expressed in terms of weight percent gain (WPG) and modification was characterized using FTIR spectroscopy. In bulk solution, microwave radiations were primarily absorbed by anhydride solutions for heating purposes and a moderate WPG was obtained. However, when microwave heating was used to modify impregnated wood specimens under no excess of anhydride, a significant enhancement in degree of modification was achieved within a few minutes. The modified wood exhibited good anti-swelling efficiency. 相似文献
110.
《Ergonomics》2012,55(11):1072-1080
The objective of this study was to evaluate individual finger force and contribution to a gripping force, the difference between actual and expected finger forces and subjective discomfort rating at 10 different submaximal voluntary contraction (%MVC) levels (10–100% in 10 increments). Seventy-two participants randomly exerted gripping force with a multi-finger force measurement system. The individual finger force, gripping force and discomfort increased as %MVC levels increased. The middle and ring fingers exerted more force and contributed to a gripping force more than the index and little fingers due to their larger mass fractions of the digit flexor muscles. It was apparent at <50% MVC; however, the index finger increased its contribution and exerted even more force than expected at more than 50% MVC. Subjective discomfort supported the results of the objective measures. This could explain the conflicting findings between index and ring fingers in previous finger contribution studies. Statement of Relevance: Hand tool design is of special interest in ergonomics due to its association with musculoskeletal disorders in the hand. This study reveals a different contribution pattern of the fingers in submaximal voluntary contraction of gripping exertion. 相似文献