全文获取类型
收费全文 | 3199篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 97篇 |
金属工艺 | 6篇 |
机械仪表 | 7篇 |
建筑科学 | 5篇 |
矿业工程 | 10篇 |
能源动力 | 8篇 |
轻工业 | 61篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
武器工业 | 1篇 |
无线电 | 46篇 |
一般工业技术 | 89篇 |
冶金工业 | 2814篇 |
原子能技术 | 4篇 |
自动化技术 | 54篇 |
出版年
2022年 | 4篇 |
2021年 | 6篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 27篇 |
2012年 | 13篇 |
2011年 | 28篇 |
2010年 | 14篇 |
2009年 | 21篇 |
2008年 | 19篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 9篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 87篇 |
1998年 | 861篇 |
1997年 | 489篇 |
1996年 | 313篇 |
1995年 | 158篇 |
1994年 | 155篇 |
1993年 | 159篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 37篇 |
1989年 | 41篇 |
1988年 | 41篇 |
1987年 | 38篇 |
1986年 | 28篇 |
1985年 | 37篇 |
1983年 | 15篇 |
1982年 | 20篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 8篇 |
1978年 | 14篇 |
1977年 | 66篇 |
1976年 | 185篇 |
1975年 | 9篇 |
1974年 | 6篇 |
1973年 | 12篇 |
1968年 | 4篇 |
1967年 | 8篇 |
1966年 | 4篇 |
排序方式: 共有3209条查询结果,搜索用时 78 毫秒
51.
Royzman Edward B.; Cassidy Kimberly Wright; Baron Jonathan 《Canadian Metallurgical Quarterly》2003,7(1):38
This article reviews the evidence and theory pertaining to a form of perspective-taking failure--a difficulty in setting aside the privileged information that one knows to be unavailable to another party. The authors argue that this bias (epistemic egocentrism, or EE) is a general feature of human cognition and has been tapped by 2 independent and largely uncommunicating research traditions: the theory-of-mind tradition in developmental psychology and, with more sensitive probes, the "heuristics and biases" tradition in the psychology of human judgment. This article sets the stage for facilitating communication between these traditions as well as for the recognition of EE's breadth and potential interdisciplinary significance. The authors propose a life-span account and a tentative taxonomy of EE; and they highlight the interdisciplinary significance of EE by discussing its implications for normative ethics. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
One impact of socioeconomic progress on populations has been to reduce the number of cases due to diseases of undernutrition and microbial contamination of food, which affected mostly infants and young children, and to increase those due to diseases of excessive food consumption, which are affecting adults and a growing number of children. This article reviews the main dietary factors which have an influence on cardiovascular disease and cancer, and discusses the link between economic development and increased rates of chronic diseases. There is evidence that the noncommunicable diseases and their risk factors have risen rapidly in countries of the WHO Western Pacific Region. Data from 29 countries and areas in the region indicate that 70% of them show lifestyle diseases in three or more of the top five causes of death. While public health measures have been implemented by some countries to prevent and control nutrition-related chronic diseases, further action is needed. 相似文献
53.
Backscattered radiation (BSR) arising from field-defining collimators and entering the beam monitor chamber (BMC) may contribute to observed variations in medical linear accelerator photon beam output with collimator setting. Measuring the magnitude of such contributions for particular accelerators under specified operating conditions is therefore important when attempting to understand and model accelerator head scatter. The present work was conducted to confirm some backscatter measurements for collimating jaws reported previously and to extend these to include other accelerators and a multileaf collimator (MLC). BSR reaching the BMC from the jaws of Clinac 600C, 2100C and 2300CD accelerators and from an MLC on the 2300CD was investigated using both target-current-pulse-counting and telescope methods. Our measurements show that for the Clinac 600C BSR-dependent output variations are negligible. However, for the 2100C and 2300CD BSR-dependent relative output increased in an almost linear fashion, by up to 2.4% for 15 and 18 MV beams, and by up to 1.7% for 6 MV beams, as the field size varied from 5 x 5 cm2 to 40 x 40 cm2. The magnitude of BSR dependent upon collimator location in the head, as expected, thereby contributing to the collimator exchange effect. An earlier study at our centre using the telescope method had reported higher BSR levels. This discrepancy was resolved when corrections for telescope block and room scatter, previously assumed negligible, were made. 相似文献
54.
We studied the long-term clinical course of five patients with chronic manganese intoxication. The mean scores of the King's College Hospital Rating Scale for Parkinson's disease increased from 15.0 +/- 4.2 in 1987 to 28.3 +/- 6.70 in 1991 and then to 38.1 +/- 12.9 in 1995. The deterioration was most prominent in gait, rigidity, speed of foot tapping, and writing. Tissue concentrations of manganese in blood, urine, scalp hair, and pubic hair returned to normal. Follow-up MRIs did not show paramagnetic high-signal intensity on T1-weighted images. The data indicate that clinical progression in patients with manganese parkinsonism continues even 10 years after cessation of exposure. 相似文献
55.
56.
W Guo RS Lovell YH Zhang BL Huang TP Burris WJ Craigen ER McCabe 《Canadian Metallurgical Quarterly》1996,178(1-2):31-34
We cloned the murine full-length cDNA encoding Ahch, the mouse homologue of DAX1 (DSS-AHC Region on Human X Chromosome, Gene1) which is the gene responsible for human X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH). Sequence analysis revealed that the murine and human cDNAs have 65% aa identity and 75% aa similarity overall. The cysteine residues in the putative DNA binding domain, which may interact with Zn2+ ions to form zinc fingers, are 100% conserved between the two species, indicating that the novel zinc-finger structures in DAX1 may be functional. In addition, mouse interspecific backcrosses show that the Ahch gene is closely linked to the glycerol kinase locus, GyK, on the mouse X chromosome, indicating that the order of the loci is conserved in this syntenic region between mouse and human. 相似文献
57.
CB McCoy SA Smith LR Metsch RS Anwyl R Correa L Bankston JJ Zavertnik 《Canadian Metallurgical Quarterly》1994,2(4):267-274
Socioeconomic status is the most significant factor influencing the decreased survival associated with breast cancer in minority groups in the United States. Barriers to the use of early detection programs by low-income women often result in the detection of breast cancer at stages too advanced to assure optimum outcomes. In an effort to increase accessibility of breast cancer screening among such individuals, the Early Detection Program (EDP) was initiated in 1987. The program provided breast cancer screening to women 40 years of age and older who attended eight primary healthcare centers located in low-income neighborhoods throughout Dade County, Florida. From its inception in October 1987 through December 1993, 23,866 medically underserved women had mammography examinations, with more than 17,000 of these women undergoing baseline mammograms. Since the program's inception, 126 cancers were diagnosed in 123 women. A dramatic shift from later to earlier stage breast cancers was observed. These results warrant a greater inclusion of medically underserved and lower socioeconomic status women in screening programs for the early detection of breast cancer. 相似文献
58.
Utilitarian and economic theories of deterrence hold that the relation of the penalty to the misdeed should be irrelevant. In 5 experiments using hypothetical cases, judgments of penalties depended on whether this relation was in kind (IK) or out of kind (OK). When victims were identifiable, IK penalties were higher than OK and preferred to OK. Subjects seemed to confuse penalties and compensation. When there were no identifiable victims (e.g., environmental damage), IK penalties were preferred, but OK penalties were higher. Here, OK judgments were more uncertain, and subjects preferred to err on the side of overpunishing. The results can be explained in terms of overgeneralization of usually useful heuristics. Alternative hypotheses concerning aggression and scale compatibility are rejected. The findings have implications for the setting of penalties in legal cases (e.g., the Exxon Valdez) and for lay theories of punishment in nonlegal settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Bipolar illness may be characterized by dysregulation and dysfunction of biologically active ions and ion pumps, respectively. In an effort to examine whether purported physiologic abnormalities may have functional counterparts, nerve conduction velocities (NCVs) and H-reflex recovery were examined in 7 acutely manic, 11 euthymic bipolar, 13 remitted schizophrenic, and 6 normal control individuals. All electrophysiologic tests were clinically normal. However, euthymic bipolar patients had significantly slower NCVs than either manic or normal individuals. Percent decrement of H-reflex recovery was nonsignificantly increased in manic versus euthymic bipolar subjects. Data analysis suggests lithium was not responsible for these changes. These data indicate that different mood states in bipolar illness are associated with alterations in electroneurophysiologic function. 相似文献
60.
RS Rosomoff 《Canadian Metallurgical Quarterly》1996,12(3):171-173
Intravesical potassium sensitivity can readily elicit abnormal epithelial permeability responses in subjects with diseased bladder, primarily interstitial cystitis. The technique involves eliciting responses in each subject to 40 cc of plain water or 40 cc of potassium chloride solution (40 mEq per 100 cc water). The subjects are asked to rate their subjective responses 3-5 minutes after instillation of the test solution and told to compare the water and potassium. An abnormal provocation to potassium but not water is considered a positive response and a useful way to delineate people with epithelial dysfunction and loss of permeability control. On the other hand, normal subjects will not respond to either the water or potassium. 相似文献