全文获取类型
收费全文 | 4053篇 |
免费 | 207篇 |
国内免费 | 94篇 |
专业分类
电工技术 | 217篇 |
综合类 | 111篇 |
化学工业 | 289篇 |
金属工艺 | 108篇 |
机械仪表 | 123篇 |
建筑科学 | 172篇 |
矿业工程 | 35篇 |
能源动力 | 75篇 |
轻工业 | 279篇 |
水利工程 | 61篇 |
石油天然气 | 48篇 |
武器工业 | 53篇 |
无线电 | 306篇 |
一般工业技术 | 236篇 |
冶金工业 | 1844篇 |
原子能技术 | 47篇 |
自动化技术 | 350篇 |
出版年
2023年 | 16篇 |
2022年 | 28篇 |
2021年 | 71篇 |
2020年 | 50篇 |
2019年 | 41篇 |
2018年 | 35篇 |
2017年 | 52篇 |
2016年 | 59篇 |
2015年 | 76篇 |
2014年 | 105篇 |
2013年 | 157篇 |
2012年 | 156篇 |
2011年 | 179篇 |
2010年 | 150篇 |
2009年 | 126篇 |
2008年 | 145篇 |
2007年 | 171篇 |
2006年 | 165篇 |
2005年 | 106篇 |
2004年 | 101篇 |
2003年 | 64篇 |
2002年 | 67篇 |
2001年 | 72篇 |
2000年 | 46篇 |
1999年 | 77篇 |
1998年 | 499篇 |
1997年 | 313篇 |
1996年 | 206篇 |
1995年 | 115篇 |
1994年 | 112篇 |
1993年 | 150篇 |
1992年 | 35篇 |
1991年 | 39篇 |
1990年 | 29篇 |
1989年 | 31篇 |
1988年 | 38篇 |
1987年 | 34篇 |
1986年 | 33篇 |
1985年 | 39篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 26篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 40篇 |
1976年 | 122篇 |
1975年 | 8篇 |
1974年 | 8篇 |
排序方式: 共有4354条查询结果,搜索用时 15 毫秒
1.
Myers Nicholas D.; Payment Craig A.; Feltz Deborah L. 《Canadian Metallurgical Quarterly》2004,8(3):182
This study examined reciprocal relationships between collective efficacy and team performance over a season of competition in women's intercollegiate ice hockey within weekends where the opponent was constant for 2 games. Collective efficacy beliefs within 12 teams were assessed prior to both games for at least 7 weekends. Team performance indexes produced an overall measure of performance for each game. The average influence of Saturday collective efficacy on Saturday performance was moderate and positive after controlling for Friday performance. The average influence of Friday performance on Saturday collective efficacy was small and positive after removing the influence of Friday collective efficacy from Friday performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Albrecht Jason E.; O'Brien Edward J.; Mason Robert A.; Myers Jerome L. 《Canadian Metallurgical Quarterly》1995,21(2):364
An implicit assumption of several causal reasoning models is that readers adopt the goals of a narrative's protagonist during text comprehension. In apparent violation of this assumption, readers participating in Experiment 1 of the present study drew inferences relevant to a protagonist's goal even when that goal was already satisfied from the perspective of the protagonist. In Experiments 2 and 3, participants were explicitly asked to view the text situation from the point of view of the protagonist. In this case, the goals of the reader and the protagonist should be the same. In these experiments, participants focused on the goals of the protagonist only when those goals had not been satisfied from the perspective of the protagonist. These results are discussed in terms of reader- and character-based perspectives and in terms of text characteristics that cue perspective taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
IH Bjerkli R Myklebust S R?is?nen S Telimaa LE Stenfors 《Canadian Metallurgical Quarterly》1996,36(3):205-213
Dopaminergic agents and carbidopa/levodopa have become the preferred treatment for both the restless legs (RL) syndrome and for periodic limb movements in sleep (PLMS). For once-nightly treatments with carbidopa/ levodopa, a problem with morning end-of-dose rebound increases in leg movements has been reported to occur in the about one-fourth of the patients. In our clinical studies a previously unreported but far more significant problem of markedly augmented RL symptoms occurred in the afternoon and the evening prior to taking the next nightly dose. A systematic prospective evaluation of this augmentation in 46 consecutive patients treated with carbidopa/ levodopa for RL syndrome or PLMS disorder found this augmentation to be the major adverse effect of treatment. Augmentation occurred for 31% of PLMS patients and 82% of all RL patients. It was greater for subjects with more severe RL symptoms and for patients on higher doses (> or = 50/200 mg carbidopa/levodopa) but was unrelated to gender, age or baseline severity of PLMS. This augmentation was severe enough to require medication change for 50% of the RL patients and 13% of PLMS patients. Augmentation resolved with cessation of the medication and could be minimized by keeping the dose low. 相似文献
4.
Recurrent erosion of the corneal epithelium has been treated successfully by phototherapeutic keratectomy when convention therapy has failed. We present a case of recurrent corneal erosion occurring 1 year after photorefractive keratectomy in a 55-year-old myopic woman. No corneal abnormalities were previously identified in either the affected or the fellow eye. This case demonstrates the potential for ineffective healing of the corneal epithelial basement membrane complex after excimer laser photorefractive keratectomy. 相似文献
5.
LE Lindner 《Canadian Metallurgical Quarterly》1993,41(3):439-445
The silver-staining technique for nucleolar organizer regions (AgNOR) of Ploton et al., as popularized by Crocker, is being widely used for evaluation of nucleolar function, especially in neoplasia. It suffers from limited reliability, background staining, precipitates, and fading of the sections. Factors were identified that affect these problems. The oxidation-reduction level and gelatin used are particularly important. An improved procedure is presented which incorporates pre-reduction of the sections, selection of an optimal gelatin, and post-treatment of the sections to produce a permanent preparation. It is compatible with many fixatives and with other stains used before or after the silver stain. 相似文献
6.
D Averill D Blockus B Brabson J Brom C Jung H Ogren DR Rust M Derrick P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano B Cork C Akerlof J Chapman D Errede MT Ken DI Meyer H Neal D Nitz R Thun R Tschirhart S Abachi P Baringer BG Bylsma R DeBonte D Koltick EH Low RL McIlwain DH Miller CR Ng EI Shibata 《Canadian Metallurgical Quarterly》1989,39(1):123-137
7.
8.
JE Myers T Mieczkowski J Perel D Abbondanza TB Cooper JJ Mann 《Canadian Metallurgical Quarterly》1994,35(2):112-120
Serotonergic responsivity was assessed in 20 psychiatric patients by the prolactin response to a fenfluramine challenge test. During the fenfluramine challenge 6 of 20 patients (30%) spontaneously reported psychopathologic reactions that included: increased anxiety/agitation, psychotic symptoms, illusions, mood elevation, and anergia. The time of peak behavioral symptoms (2.5 +/- 0.8 hrs) corresponded closely to the time of peak increase in prolactin levels (3.0 +/- 1.1 hr). Abnormal behavioral responders had statistically significant greater increases in prolactin 1 to 4 hr after fenfluramine when compared to normal responders. Patients who developed an abnormal psychopathologic response to fenfluramine were characterized by higher levels of anxiety and agitation at the time of admission to the hospital but otherwise were not distinguishable on the basis of severity of other psychiatric symptoms. This study suggests that increased serotonergic transmission may trigger anxiety, psychosis, and mood elevation in specific vulnerable individuals, whereas other patients with similar psychiatric illnesses are not affected. 相似文献
9.
The technique of immunocytochemistry was used to identify myoglobin in kidney, confirming a diagnosis of neuroleptic malignant syndrome following an otherwise obscure autopsy in a decomposed body. The features of neuroleptic malignant syndrome are reviewed with a differential diagnosis of myoglobin renal casts. The report emphasizes a thorough and detailed assessment of deaths which occur during treatment with neuroleptic drugs. 相似文献
10.
We developed a new in vitro model of neuronal injury using NT2-N cells to examine the effects of hydrodynamic loading rate on intraneuronal calcium dynamics and lactate dehydrogenase (LDH) release. Our apparatus consisted of a parallel disk viscometer which induced fluid shear stress with well-defined magnitudes and loading rates to cultured cells. We found that the deformation response of the cells was dependent on the severity of the insult, with increased cellular strains generated for higher shear stresses at a constant loading rate. Peak intracellular free calcium concentration correlated with strain, suggesting that mechanical deformation may regulate calcium response. Slowly applied fluid shear stress elicited no response, whereas high loading rates resulted in peak calcium increases 2.9 to 3.6 times baseline values as injury severity was increased. LDH release measured within 5 min after the insult correlated with loading rate. In addition, LDH release continued to increase out to 24 h following high loading rate conditions, demonstrating that the application of fluid shear stress led to prolonged cell damage. The acute response in NT2-N cells subjected to an insult with the CSID is dependent on the loading rate, and these results suggest that initial membrane deformation may trigger subsequent events. 相似文献