全文获取类型
收费全文 | 823篇 |
免费 | 22篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 178篇 |
金属工艺 | 8篇 |
机械仪表 | 14篇 |
建筑科学 | 37篇 |
矿业工程 | 2篇 |
能源动力 | 12篇 |
轻工业 | 83篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 57篇 |
一般工业技术 | 138篇 |
冶金工业 | 193篇 |
原子能技术 | 14篇 |
自动化技术 | 98篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 49篇 |
2012年 | 23篇 |
2011年 | 34篇 |
2010年 | 28篇 |
2009年 | 32篇 |
2008年 | 35篇 |
2007年 | 39篇 |
2006年 | 28篇 |
2005年 | 27篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 21篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 16篇 |
1998年 | 50篇 |
1997年 | 34篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 17篇 |
1976年 | 23篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1969年 | 8篇 |
1968年 | 4篇 |
排序方式: 共有847条查询结果,搜索用时 15 毫秒
81.
G. Albrecht 《Fibre Chemistry》1995,26(4):282-283
Translated from Khimicheskie Volokna, No. 4, pp. 66–67, July–August, 1994. 相似文献
82.
A. Pollatsek, E. D. Reichle, and K. Rayner (see record 2006-22004-014) argue that the critical findings in A. W. Inhoff, B. M. Eiter, and R. Radach (see record 2005-13471-012) are in general agreement with core assumptions of sequential attention shift models if additional assumptions and facts are considered. The current authors critically discuss the hypothesized time line of processing and indicate that the success of Pollatsek et al.'s simulation is predicated on a gross underestimation of the pretarget word's viewing duration in Inhoff et al. and that the actual data are difficult to reconcile with the strictly serial attention shift assumption. The authors also discuss attention shifting and saccade programming assumptions in the E-Z Reader model and conclude that these are not in harmony with research in related domains of study. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
83.
84.
The MBE growth of In/sub 0.52/Ga/sub 0.18/Al/sub 0.30/As ( lambda /sub g/=1.06 mu m) layers in the temperature range of 400-450 degrees C was demonstrated to give high-quality optical waveguides which not only exhibit low propagation losses as low as 0.5 dB/cm at lambda =1.55 mu m but concomitantly high resistivity of >10/sup 4/ Omega cm. The refractive index of In/sub 0.52/Ga/sub 0.18/Al/sub 0.30/As was estimated to be 3.207+or-0.03 at lambda =1.55 mu m.<> 相似文献
85.
Based on the understanding of mode-locking dynamics in homogeneously broadened media, active mode-lockedQ -switched YAG and YLF oscillators have emerged as the preferred source of highly controllable, reproducible, and synchronizable mode-locked pulses. This paper describes the modification of such a system for use with glass as the active medium. The emphasis is on measurements determining the mode-locking behavior of this laser. 相似文献
86.
87.
Rayner Keith; Pollatsek Alexander; Drieghe Denis; Slattery Timothy J.; Reichle Erik D. 《Canadian Metallurgical Quarterly》2007,136(3):520
R. Kliegl, A. Nuthmann, and R. Engbert (see record 2006-01956-002) reported an impressive set of data analyses dealing with the influence of the prior, present, and next word on the duration of the current eye fixation during reading. They argued that outcomes of their regression analyses indicate that lexical processing is distributed across a number of words during reading. The authors of this comment question their conclusions and address 4 different issues: (a) whether there is evidence for distributed lexical processing, (b) whether so-called parafoveal-on-foveal effects are widespread, (c) the role of correlational analyses in reading research, and (d) problems in their analyses because they use only cases in which words are fixated exactly once. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
88.
H Albrecht M Schwecht W P?llmann D Parag LP Erasmus N K?nig 《Canadian Metallurgical Quarterly》1998,69(12):1066-1073
Upper limb ataxia is one of the most disabling symptoms of patients with multiple sclerosis (MS). There are some clinically tested therapeutic strategies, especially with regard to cerebellar tremor. But most of the methods used for treatment of limb ataxia in physiotherapy and occupational therapy are not systematically evaluated, e.g. the effect of local ice applications, as reported by MS patients and therapists, respectively. We investigated 21 MS patients before and in several steps 1 up to 45 min after cooling the most affected forearm. We used a series of 6 tests, including parts of neurological status and activities of daily living as well. At each step skin temperature and nerve conduction velocity were recorded. All tests were documented by video for later offline analysis. Standardized evaluation was done by the investigators and separately by an independent second team, both of them using numeric scales for quality of performance. After local cooling all patients showed a positive effect, especially a reduction of intentional tremor. In most cases this effect lasted 45 min, in some patients even longer. We presume that a decrease in the proprioceptive afferent inflow-induced by cooling-may be the probable cause of this reduction of cerebellar tremor. Patients can use ice applications as a method of treating themselves when a short-time reduction of intention tremor is required, e.g. for typing, signing or self-catheterization. 相似文献
89.
90.
Although fetal pituitary ACTH is important to fetal adrenal growth and steroidogenesis in the second half of primate pregnancy, its role in adrenal development and function has not been established in vivo in the first half of gestation. In the present study, therefore, baboons were treated at midgestation with betamethasone to determine the effect of fetal pituitary ACTH on fetal adrenal growth, development, and ACTH receptor and P-450 enzyme messenger ribonucleic acid (mRNA) levels. The administration of betamethasone to baboon mothers on days 60-99 of gestation (term = 184 days) decreased fetal pituitary POMC mRNA levels by 54% (P < 0.01) and fetal serum ACTH levels to undetectable values (P < 0.05). The decline in ACTH was associated with decreases in fetal adrenal weight (P < 0.001), cortical cell size (P < 0.05), appearance of apoptosis and cellular disorganization, and a loss of immunocytochemically demonstrable definitive zone-specific delta5-3beta-hydroxysteroid dehydrogenase expression. The concomitant administration of ACTH and betamethasone restored these aspects of adrenal integrity to normal. Moreover, there was approximately a 95% decrease (P < 0.01) in fetal adrenal expression of ACTH receptor, P-450 cholesterol side-chain cleavage, and P-450 17alpha-hydroxylase 17/20-lyase mRNA levels after betamethasone administration. We conclude that fetal pituitary ACTH is necessary for the growth and development of fetal and definitive cortical zones and the marked coordinated increase in ACTH receptor and maintenance of P-450 cholesterol side-chain cleavage/P-450 17alpha-hydroxylase 17/20-lyase expression in the baboon fetal adrenal gland during the first half of gestation. 相似文献