全文获取类型
收费全文 | 3049篇 |
免费 | 51篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 26篇 |
综合类 | 3篇 |
化学工业 | 637篇 |
金属工艺 | 46篇 |
机械仪表 | 54篇 |
建筑科学 | 154篇 |
矿业工程 | 43篇 |
能源动力 | 72篇 |
轻工业 | 253篇 |
水利工程 | 14篇 |
石油天然气 | 9篇 |
无线电 | 203篇 |
一般工业技术 | 351篇 |
冶金工业 | 875篇 |
原子能技术 | 23篇 |
自动化技术 | 341篇 |
出版年
2022年 | 25篇 |
2021年 | 47篇 |
2020年 | 24篇 |
2019年 | 23篇 |
2018年 | 25篇 |
2017年 | 36篇 |
2016年 | 44篇 |
2015年 | 35篇 |
2014年 | 42篇 |
2013年 | 235篇 |
2012年 | 76篇 |
2011年 | 94篇 |
2010年 | 78篇 |
2009年 | 90篇 |
2008年 | 78篇 |
2007年 | 115篇 |
2006年 | 87篇 |
2005年 | 79篇 |
2004年 | 78篇 |
2003年 | 69篇 |
2002年 | 75篇 |
2001年 | 51篇 |
2000年 | 42篇 |
1999年 | 59篇 |
1998年 | 52篇 |
1997年 | 52篇 |
1996年 | 62篇 |
1995年 | 53篇 |
1994年 | 66篇 |
1993年 | 52篇 |
1992年 | 45篇 |
1990年 | 58篇 |
1989年 | 44篇 |
1988年 | 40篇 |
1987年 | 39篇 |
1986年 | 50篇 |
1985年 | 41篇 |
1984年 | 48篇 |
1983年 | 38篇 |
1982年 | 46篇 |
1981年 | 37篇 |
1980年 | 35篇 |
1979年 | 53篇 |
1978年 | 42篇 |
1977年 | 40篇 |
1976年 | 26篇 |
1975年 | 34篇 |
1974年 | 43篇 |
1971年 | 26篇 |
1970年 | 25篇 |
排序方式: 共有3104条查询结果,搜索用时 46 毫秒
991.
Discusses the efforts of the APA Central Office to correct the image of psychology on the network television show The Eleventh Hour. The author objects to APA's policing the image of psychology in entertainment media (not news, nonfiction features, or documentaries). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
992.
To test Beck's interpretation of the Rorschach Y determinant, 10 Low Y and 10 High Y male psychiatric inpatients were obtained from 4 hospitals. The hypothesis that High Y Ss are more resigned and inhibited than Low Y Ss was tested with 2 kinds of data about the overt behavior of the sample: interviews with the Ss and interviews with 3 staff members having contacts with them. The Patient Interviews confirmed the hypothesis at the .05 level. The Staff Interviews differentiated the Ss in the predicted direction at the .05 level on small psychiatric wards but not on a large ward. 2 hypotheses about this inconsistency are presented for future investigation. Clinical interpretation of the shading determinant is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
993.
Arthur W. Sleight 《Materials Research Bulletin》1974,9(9):1185-1190
Cd2V2O71bII has been prepared at about 80 kbars pressure. This new compound has a structure related to that of pyrochlore, but the symmetry is distorted from cubic to monoclinic. Solid solutions of the types Cd2V2?xNbxO7 and Cd2?xAxV2O7 (A = In or T1) were prepared at 58 kbars. Attempts to confirm previous reports of A1+A3+V2O7 pyrochlores were unsuccessful. 相似文献
994.
Arthur E. Waltking George W. Bleffert Marshall Chick Rosemary Fogerty 《Journal of the American Oil Chemists' Society》1973,50(10):424-425
Gas liquid chromatography was used to determine the composition of the benzene-ethanol-water (BEW) solvent system frequently
used in the separation of aflatoxins by thin layer chromatography. Investigation of a rapid procedure for preparing and using
this solvent system led to the discovery of a new BEW solvent system with advantages for the routine determination of aflatoxins
in roasted nut products, which consists of benzene-ethanol-water 40:6:3 for the trough solution and 4:27:20 for the bottom
solution. 相似文献
995.
Newborn rats were segregated into litters of 6 and 22 pups. Undernourished groups were maintained for 21 and 53 days at which
time a portion of each group was sacrificed and the remainder refed until 121 days. The amount of myelin isolated from the
central nervous system was decreased in nutritionally deprived animals but there was little change in its chemical composition
or intereference in the normal chemical maturation of the membrane. The only consistent change was a reduction in phosphatidyl
ethanolamine plasmalogen. This deficit tended to be corrected by nutritional rehabilitation and was most complete in those
animals refed ad lib. diets for the longest time periods prior to sacrifice. The relatively normal chemical composition of
myelin obtained from undernourished animals differs from changes described in myelin membranes isolated from patients with
destructive or degenerative diseases of the nervous system. This seems to be further evidence that the reduction in myelination
in undernutrition is a result of decreased synthesis of the membrane. 相似文献
996.
Suggests that the study of informed consent by E. Berscheid et al (see record 1974-11173-001) violates 2 principles of the Ethical Standards for Research with Human Subjects. The debriefing by mail and the failure of the researchers to make sure that the Ss learned anything as a result of their participation in the study are criticized. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
997.
998.
The properties of d.c. sputtered molybdenum-silicon Schottky diodes are described. Although it is possible to produce near ideal characteristics when a low sputtering voltage is used for a short time, increased voltage and time lead to significant deviation from the ideal. A model is proposed which is capable of explaining most features of the observed C-V and I-V characteristics. This model assumes that sputtering damage causes donor-like traps to be created close to the semiconductor surface. It is found that an exponential distribution of traps with characteristic length in the range 10–100 A and an energy level of 0·43 eV below the conduction band is sufficient to account for the observed characteristics. The modification to the I–V characteristics is due to tunnelling through the top of the Schottky barrier where it is narrowed by the presence of the excess trapped charge. 相似文献
999.
"Normals and schizophrenics were asked to predict on a rating scale the responses of three Ss: an associate, a normal, and a psychotic, the latter two persons known only through an observed interview situation. Individuals in each group had previously made self-ratings in terms of the same scale. Deviation scores for members of each group provided a measure of accuracy of prediction (empathy) and the tendency to assume a similarity between oneself and another person (assumed similarity). The control group revealed generally greater empathic ability and greater assumed similarity than did the schizophrenic group." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
1000.
Mentions several psychology highlights occurring over the last year. The article begins with a general overview of recent significant accomplishments that increased the recognition of psychology. Then the author offers that his primary purpose is to step back from the day-to-day activities of the American Psychological Association (APA) and to report on some of the fundamental activities from the perspective of the last 3 to 5 years. He speaks to the governance of APA, then discusses recent developments on the operational side of APA, and, finally, directs attention to the area of public affairs and APA's role. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献