全文获取类型
收费全文 | 2369篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 80篇 |
金属工艺 | 14篇 |
机械仪表 | 4篇 |
建筑科学 | 28篇 |
矿业工程 | 1篇 |
能源动力 | 6篇 |
轻工业 | 35篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 46篇 |
一般工业技术 | 71篇 |
冶金工业 | 2028篇 |
原子能技术 | 11篇 |
自动化技术 | 39篇 |
出版年
2021年 | 3篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 18篇 |
2012年 | 15篇 |
2011年 | 26篇 |
2010年 | 16篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 20篇 |
2004年 | 14篇 |
2003年 | 23篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1999年 | 82篇 |
1998年 | 653篇 |
1997年 | 344篇 |
1996年 | 227篇 |
1995年 | 139篇 |
1994年 | 124篇 |
1993年 | 129篇 |
1992年 | 12篇 |
1991年 | 25篇 |
1990年 | 36篇 |
1989年 | 20篇 |
1988年 | 30篇 |
1987年 | 12篇 |
1986年 | 20篇 |
1985年 | 14篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 50篇 |
1976年 | 98篇 |
1975年 | 9篇 |
1974年 | 3篇 |
1973年 | 10篇 |
1972年 | 4篇 |
1969年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有2381条查询结果,搜索用时 15 毫秒
71.
A Potent Inhibitor of Protein Sequestration by Expanded Triplet (CUG) Repeats that Shows Phenotypic Improvements in a Drosophila Model of Myotonic Dystrophy
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
72.
Titus S. Seilheimer Patrick L. Zimmerman Kirk M. Stueve Charles H. Perry 《Journal of Great Lakes research》2013
The Great Lakes watersheds have an important influence on the water quality of the nearshore environment, therefore, watershed characteristics can be used to predict what will be observed in the streams. We used novel landscape information describing the forest cover change, along with forest census data and established land cover data to predict total phosphorus and turbidity in Great Lakes streams. In Lake Superior, we modeled increased phosphorus as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, and agricultural land, and we modeled increased turbidity as a function of the increase in the proportion of persisting forest, forest disturbed during 2000–2009, agricultural land, and urban land. In Lake Michigan, we modeled increased phosphorus as a function of ecoregion, decrease in the proportion of forest disturbed during 1984–1999 and watershed storage, and increase in the proportion of urban land, and we modeled increased turbidity as a function of ecoregion, increase in the proportion of forest disturbed during 2000–2009, and decrease in the proportion softwood forest. We used these relationships to identify priority areas for restoration in the Lake Superior basin in the southwestern watersheds, and in west central and southwest watersheds of the Lake Michigan basin. We then used the models to estimate water quality in watersheds without observed instream data to prioritize those areas for management. Prioritizing watersheds will aid effective management of the Great Lakes watershed and result in efficient use of restoration funds, which will lead to improved nearshore water quality. 相似文献
73.
Zimmerman Jeffrey; Hess Allen K.; McGarrah Nancy A.; Benjamin G. Andrew H.; Ally Glenn A.; Gollan Jackie K.; Kaser-Boyd Nancy 《Canadian Metallurgical Quarterly》2009,40(6):539
The provision of psychological (e.g., psychotherapy, coparenting, mediation, collaborative divorce, child custody evaluation) services for families of divorce are growing specialties for many clinical and forensic psychologists. However, practice in domestic relations psychology, such as divorce and custody assessment and testimony, is a high-risk venture for incurring ethics complaints and law suits. The lead article and the three commentaries that follow enumerate the various roles practitioners might play, clarify how each role requires specific skill sets that may be outside one’s particular competence and necessitate additional training, describe how countertransferential issues arise, urge meticulous record keeping, discuss some of the subtleties of confidentiality and the releasing of information, describe how transparency in clarifying expectations leads to a lowering of contentiousness, and provide tips for divorce and forensic practice. The special challenges associated with psychologists being tempted to move beyond their role on a case and those of particularly high-risk situations (e.g., complaints of child abuse or domestic violence) are also discussed. Suggestions are offered to help psychologists better serve the public while taking steps to better inoculate themselves from complaints. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
L.M. Hale X. Zhou J.A. Zimmerman N.R. Moody R. Ballarini W.W. Gerberich 《Computational Materials Science》2011,50(5):1651-1660
Molecular dynamics has been used to simulate the uniaxial compression of single crystal silicon nanospheres using the Tersoff potential. The resulting yield behavior is shown to vary with changes in temperature, sphere size, and crystallographic orientation with respect to the loading direction. Only compression along the [1 0 0] crystallographic direction resulted in the formation of the β-Sn phase. A temperature dependent hardening response is observed in all orientations independent of the β-Sn phase transformation. Dislocation activity is detected at elevated temperatures in the largest sphere indicating a critical temperature and size for nucleation. Consequences of these dislocations to simulating strength properties at the nanoscale are discussed. 相似文献
75.
CK Combs DE Johnson SB Cannady TM Lehman GE Landreth 《Canadian Metallurgical Quarterly》1999,19(3):928-939
Microglial interaction with amyloid fibrils in the brains of Alzheimer's and prion disease patients results in the inflammatory activation of these cells. We observed that primary microglial cultures and the THP-1 monocytic cell line are stimulated by fibrillar beta-amyloid and prion peptides to activate identical tyrosine kinase-dependent inflammatory signal transduction cascades. The tyrosine kinases Lyn and Syk are activated by the fibrillar peptides and initiate a signaling cascade resulting in a transient release of intracellular calcium that results in the activation of classical PKC and the recently described calcium-sensitive tyrosine kinase PYK2. Activation of the MAP kinases ERK1 and ERK2 follows as a subsequent downstream signaling event. We demonstrate that PYK2 is positioned downstream of Lyn, Syk, and PKC. PKC is a necessary intermediate required for ERK activation. Importantly, the signaling response elicited by beta-amyloid and prion fibrils leads to the production of neurotoxic products. We have demonstrated in a tissue culture model that conditioned media from beta-amyloid- and prion-stimulated microglia or from THP-1 monocytes are neurotoxic to mouse cortical neurons. This toxicity can be ameliorated by treating THP-1 cells with specific enzyme inhibitors that target various components of the signal transduction pathway linked to the inflammatory responses. 相似文献
76.
L Dupclay MT Rupp RW Bennett TM Jarnagin 《Canadian Metallurgical Quarterly》1999,39(1):74-81; quiz 105-6
OBJECTIVE: To measure grocery chain pharmacists' work-related behaviors to assess the impact of a Pharmaceutical Care Certificate Program (PCCP) and other future interventions intended to alter pharmacists' practice behaviors. DESIGN: This study used multidimensional work sampling (MWS), a work measurement methodology that breaks "work" into three components: activity (what was done), contact (with whom the activity was performed), and function (the purpose or objective of the activity). Pharmacists were signaled at random intervals during the workday by a random signal generator. A selection was made from a list of items in each of the three dimensions of work to form an activity-contact-function combination code that described the work-related behavior at that point in time. SETTING AND PARTICIPANTS: Pharmacists in 15 grocery chain stores in the Indianapolis area; 20 pharmacists were enrolled in Purdue University's PCCP and 10 served as controls. Data were collected for a period of six weeks during April through June 1997 before the beginning of the PCCP program. MAIN OUTCOME MEASURES: Pharmacists' work-related behaviors. RESULTS: Writing/keyboarding was the most frequently recorded activity (22%), followed by one-to-one meetings (21.6%), and drug preparation (18%). Pharmacists spent most of their time working alone (62.9%), while a smaller but still substantial proportion of time was spent interacting with patients (17.9%). The most frequently recorded purpose (i.e., function) of pharmacists' activities was drug distribution (23.9%), followed by personal time (12.4%), receiving or transferring a medication order (10.2%), and patient counseling (6.6%). Out of a possible, 1,760 activity-contact-function combinations, 10 accounted for 46.3% of all reported observations, with "Prepare drug-Self-Drug distribution" representing the most frequently recorded activity-contact-function combination (15.7%). CONCLUSION: MWS is useful in helping grocery chain management better understand how pharmacy personnel are currently being utilized. This study provides a baseline for evaluating the impact of training programs or other alterations in the practice environment on pharmacists' work-related behaviors. 相似文献
77.
A.M. Al-Ajmi R.W. Zimmerman 《International Journal of Rock Mechanics and Mining Sciences》2006,43(8):1200-1211
A main aspect of wellbore stability analysis is the selection of an appropriate rock failure criterion. The most commonly used criterion for brittle failure of rocks is the Mohr–Coulomb criterion. This criterion involves only the maximum and minimum principal stresses, σ1 and σ3, and therefore assumes that the intermediate stress σ2 has no influence on rock strength. As the Mohr–Coulomb criterion ignores the strengthening effect of the intermediate stress, it is expected to be too conservative in estimating the critical mud weight required to maintain wellbore stability. Recently, Al-Ajmi and Zimmerman [Relationship between the parameters of the Mogi and Coulomb failure criterion. Int J Rock Mech Min Sci 2005;42(3):431–39.] developed the Mogi–Coulomb failure criterion, and showed that it is reasonably accurate in modelling polyaxial failure data from a variety of rocks. We then develop a model for the stability of vertical boreholes, using linear elasticity theory to calculate the stresses, and the fully-polyaxial Mogi–Coulomb criterion to predict failure. Our model leads to easily computed expressions for the critical mud weight required to maintain wellbore stability. 相似文献
78.
TM Field 《Canadian Metallurgical Quarterly》1998,53(12):1270-1281
Massage therapy is older than recorded time, and rubbing was the primary form of medicine until the pharmaceutical revolution of the 1940s. Popularized again as part of the alternative medicine movement, massage therapy has recently received empirical support for facilitating growth, reducing pain, increasing alertness, diminishing depression, and enhancing immune function. In this article studies are reviewed that document these effects, and models are proposed for potential underlying mechanisms. 相似文献
79.
80.
TM Wadas 《Canadian Metallurgical Quarterly》1998,29(10):48E, 48H-48E, 48K
A hospital implements a mock code program to increase nurses' comfort and skill with increased code arrest duties, improving their performance 95%. 相似文献