全文获取类型
收费全文 | 4891篇 |
免费 | 299篇 |
国内免费 | 232篇 |
专业分类
电工技术 | 56篇 |
综合类 | 514篇 |
化学工业 | 481篇 |
金属工艺 | 86篇 |
机械仪表 | 41篇 |
建筑科学 | 946篇 |
矿业工程 | 144篇 |
能源动力 | 41篇 |
轻工业 | 145篇 |
水利工程 | 75篇 |
石油天然气 | 1429篇 |
武器工业 | 6篇 |
无线电 | 55篇 |
一般工业技术 | 256篇 |
冶金工业 | 1053篇 |
原子能技术 | 19篇 |
自动化技术 | 75篇 |
出版年
2024年 | 9篇 |
2023年 | 46篇 |
2022年 | 124篇 |
2021年 | 131篇 |
2020年 | 121篇 |
2019年 | 71篇 |
2018年 | 86篇 |
2017年 | 106篇 |
2016年 | 91篇 |
2015年 | 118篇 |
2014年 | 175篇 |
2013年 | 178篇 |
2012年 | 278篇 |
2011年 | 384篇 |
2010年 | 328篇 |
2009年 | 301篇 |
2008年 | 294篇 |
2007年 | 348篇 |
2006年 | 334篇 |
2005年 | 309篇 |
2004年 | 245篇 |
2003年 | 294篇 |
2002年 | 243篇 |
2001年 | 206篇 |
2000年 | 120篇 |
1999年 | 84篇 |
1998年 | 84篇 |
1997年 | 59篇 |
1996年 | 54篇 |
1995年 | 42篇 |
1994年 | 32篇 |
1993年 | 18篇 |
1992年 | 20篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1967年 | 2篇 |
1965年 | 3篇 |
1964年 | 7篇 |
1955年 | 2篇 |
排序方式: 共有5422条查询结果,搜索用时 15 毫秒
21.
This paper discusses the seafloor thermalwater spout sedimentary activity in South Yongmei Depression according to the following
evidences: the Yongmei region was in an extended tectonic environment of metaplateform and locally developed intracontinental
rift aulacogen in company with the activity of rich alkali, high potassium volcanics of double-peak type. Several kinds of
hydrothermal sedimentary rocks and the ore-bearing sedimentary formations of copper-polymetals, iron and manganese exist in
this region with a zoning feature of the seafloor thermalwater spout sedimentation.
Project supported by the Science Foundation of NECC for Returns
Synopsis of the first author Wu Chengjian, associated professor, born in 1957, majoring in ore deposit and mineralgraphy. 相似文献
22.
Tucker Don M.; Luu Phan; Frishkoff Gwen; Quiring Jason; Poulsen Catherine 《Canadian Metallurgical Quarterly》2003,112(4):667
Functional neuroimaging suggests that limbic regions of the medial frontal cortex may be abnormally active in individuals with depression. These regions, including the anterior cingulate cortex, are engaged in both action regulation, such as monitoring errors and conflict, and affect regulation, such as responding to pain. The authors examined whether clinically depressed subjects would show abnormal sensitivity of frontolimbic networks as they evaluated negative feedback. Depressed subjects and matched control subjects performed a video game in the laboratory as a 256-channel EEG was recorded. Speed of performance on each trial was graded with a feedback signal of A, C, or F. By 350 ms after the feedback signal, depressed subjects showed a larger medial frontal negativity for all feedback compared with control subjects with a particularly striking response to the F grade. This response was strongest for moderately depressed subjects and was attenuated for subjects who were more severely depressed. Localization analyses suggested that negative feedback engaged sources in the anterior cingulate and insular cortices. These results suggest that moderate depression may sensitize limbic networks to respond strongly to aversive events. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
24.
该文分析了应用袋装炸药装填水孔爆破产生拒爆、"冲天炮"、根底偏高和爆破效果差等问题,然而应用乳化炸药混装车装填水孔可以解决这些问题,并且爆破后具有根底平整、大块率低、毒气少和综合效益高等优点.以三峡永久船闸旁侧泄水箱涵工程和江苏田湾核电站工程为例进行了分析. 相似文献
25.
26.
27.
In contrast to D. C. Zuroff, M. Mongrain, and D. A. Santor (2004), the current authors find the promissory note of dependency-sociotropy (DEP-SOC) and self-criticism-autonomy (SC-AUT) as a model of risk for depression to be in default. The authors propose reorganizing what has been cast as unitary effort into 3 distinct endeavors: a psychoanalytic clinical theory, development of a refined empirical model of risk for clinical depression, and research examining the effects of DEP-SOC and SC-AUT on interpersonal relationships in nonclinical samples. The authors identify some issues that need to be accommodated regardless of whether the assessment of Zuroff et al. (2004) or their own is accepted. DEP-SOC and SC-AUT are best construed as correlated, continuous dimensions. Future work also needs to accommodate depression as chronic recurrent condition, advances in developmental psychopathology, and more stringent criteria for positing a risk factor for clinical disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
This paper presents the data of tensile strength of water in depression tank whichwere measured by small venturi during cavitation investigation of a series of real project models.These measurements show that in depression tank water has slight tensile strength in case of highvacuum.But it influences the incipient cavitation number.In tests we also studied the influenceof tensile strength on scale effect of cavitation models. 相似文献
29.
Castonguay Louis G.; Schut Alexander J.; Aikens Deane E.; Constantino Michael J.; Laurenceau Jean-Philippe; Bologh Laura; Burns David D. 《Canadian Metallurgical Quarterly》2004,14(1):4
This study is a preliminary investigation of an integrative treatment aimed at improving the efficacy of cognitive therapy (CT) for depression. The development of the treatment protocol was based on process findings, which suggested that strategies used in CT to resolve alliance ruptures may actually exacerbate problems in the therapeutic relationship. The protocol integrates, within the traditional CT treatment manual, procedures to repair alliance ruptures that are derived from or consistent with humanistic and interpersonal therapies. Although conducted by inexperienced therapists, the integrative treatment led to greater improvement than a waiting-list condition. The results also compare favorably to previous findings for CT. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
De Fruyt Filip; Van Leeuwen Karla; Bagby R. Michael; Rolland Jean-Pierre; Rouillon Frédéric 《Canadian Metallurgical Quarterly》2006,18(1):71
Structural, mean- and individual-level, differential, and ipsative personality continuity were examined in 599 patients treated for major depression assigned to 1 of 6 forms of a 6-month pharmaco-psychotherapy program. Covariation among traits from the Five Factor model remained invariant across treatment, and patients described themselves as slightly more extraverted, open to experience, agreeable and conscientious, and substantially more emotional stable after treatment. Trait changes were only to a small extent explained by changes in depression severity. There was evidence for differential, individual-level, and ipsative stability, with stable personality profiles in terms of shape and to a lesser extent in terms of scatter and elevation. Traits remain relatively stable, except for emotional stability, despite the depressive state and the psychopharmacological interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献