首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   215篇
  免费   0篇
电工技术   3篇
化学工业   11篇
金属工艺   7篇
机械仪表   1篇
轻工业   5篇
无线电   9篇
一般工业技术   45篇
冶金工业   121篇
自动化技术   13篇
  2021年   1篇
  2015年   1篇
  2013年   4篇
  2012年   3篇
  2011年   4篇
  2010年   1篇
  2009年   4篇
  2008年   5篇
  2007年   5篇
  2006年   1篇
  2005年   3篇
  2004年   3篇
  2003年   4篇
  2002年   4篇
  2001年   2篇
  2000年   5篇
  1999年   7篇
  1998年   31篇
  1997年   18篇
  1996年   13篇
  1995年   10篇
  1994年   7篇
  1993年   8篇
  1992年   9篇
  1991年   8篇
  1990年   3篇
  1989年   5篇
  1988年   4篇
  1987年   1篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   4篇
  1981年   5篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1977年   7篇
  1976年   4篇
  1975年   4篇
  1974年   1篇
  1973年   2篇
  1972年   1篇
排序方式: 共有215条查询结果,搜索用时 62 毫秒
81.
The goal of this research was to produce homogenized milk containing 2% fat with a refrigerated shelf life of 60 to 90 d using minimum high temperature, short time (HTST) pasteurization in combination with other nonthermal processes. Raw skim milk was microfiltered (MF) using a Tetra Alcross MFS-7 pilot plant (Tetra Pak International SA, Pully, Switzerland) equipped with Membralox ceramic membranes (1.4 μm and surface area of 2.31 m2; Pall Corp., East Hills, NY). The unpasteurized MF skim permeate and each of 3 different cream sources were blended together to achieve three 2% fat milks. Each milk was homogenized (first stage: 17 MPa, second stage: 3 MPa) and HTST pasteurized (73.8°C for 15 s). The pasteurized MF skim permeate and the 3 pasteurized homogenized 2% fat milks (made from different fat sources) were stored at 1.7 and 5.7°C and the standard plate count for each milk was determined weekly over 90 d. When the standard plate count was >20,000 cfu/mL, it was considered the end of shelf life for the purpose of this study. Across 4 replicates, a 4.13 log reduction in bacteria was achieved by MF, and a further 0.53 log reduction was achieved by the combination of MF with HTST pasteurization (73.8°C for 15 s), resulting in a 4.66 log reduction in bacteria for the combined process. No containers of MF skim milk that was pasteurized after MF exceeded 20,000 cfu/mL bacteria count during 90 d of storage at 5.7°C. The 3 different approaches used to reduce the initial bacteria and spore count of each cream source used to make the 2% fat milks did not produce any shelf-life advantage over using cold separated raw cream when starting with excellent quality raw whole milk (i.e., low bacteria count). The combination of MF with HTST pasteurization (73.8°C for 15 s), combined with filling and packaging that was protected from microbial contamination, achieved a refrigerated shelf life of 60 to 90 d at both 1.7 and 5.7°C for 2% fat milks.  相似文献   
82.
Online games have exploded in popularity, but for many researchers access to players has been difficult. The study reported here is the first to collect a combination of survey and behavioral data with the cooperation of a major virtual world operator. In the current study, 7,000 players of the massively multiplayer online game (MMO) EverQuest 2 were surveyed about their offline characteristics, their motivations and their physical and mental health. These self‐report data were then combined with data on participants’ actual in‐game play behaviors, as collected by the game operator. Most of the results defy common stereotypes in surprising and interesting ways and have implications for communication theory and for future investigations of games.  相似文献   
83.
Memorializes Dorothy Dinnerstein (1923–1992), known for her understanding of the psychology of sexual conservatism and the inertia and neurosis that supported it. She was author of the psychology and women's studies classic, The Mermaid and the Minotaur: Sexual Arrangements and Human Malaise, which focused on her human project of sexual liberty, a "project of loosening and restructuring the rigid forms of symbiosis, of fixed psychological complementarity, which have so far dominated relations between men and women." She was also an ardent social and political activist. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
84.
Editorial     
  相似文献   
85.
OBJECTIVE: To evaluate clinical, laboratory, radiographic, ultrasonographic, surgical, and histologic findings in ferrets with insulinoma and to determine their long-term outcome. DESIGN: Retrospective study. ANIMALS: 57 ferrets with a histopathologic diagnosis of pancreatic islet cell tumor. PROCEDURE: Medical records of ferrets with pancreatic islet cell tumors were reviewed. RESULTS: Lethargy, weakness, and collapse were the most common clinical signs. All ferrets had hypoglycemia, and hyperinsulinemia was documented in 39 of 47 (83%) ferrets. Ultrasonographic examination of the abdomen revealed pancreatic nodules in 5 of 23 ferrets. Surgical treatment was performed in 50 ferrets, 3 were treated by medical management alone, and 4 did not have treatment. At the time of surgery, 1 pancreatic nodule was found in 13 (26%) ferrets and multiple nodules were found in 37 (74%) ferrets. Pancreatic carcinoma alone was found in 34 ferrets. Whereas a combination of carcinoma and either hyperplasia or adenoma was found in 23 ferrets; 4 ferrets had metastasis to regional lymph nodes or liver. In 26 (53%) ferrets, hypoglycemia persisted after surgery, necessitating medical treatment with prednisone, diazoxide, or both. Sixteen (33%) ferrets had redevelopment of hypoglycemia at 1 to 23.5 months (median, 10.6 months) after surgery. Only 7 of the 50 (14%) ferrets remained euglycemic after surgery. CLINICAL IMPLICATIONS: In ferrets, surgical removal of insulin-secreting pancreatic islet cell tumors is recommended as definitive treatment; however, multiple pancreatic nodules are common, making complete excision of all tumor tissue difficult. Persistent hypoglycemia after surgical treatment indicates that lifelong medical management with prednisone or diazoxide or both may be necessary in many ferrets. Finally, because the insulin-secreting tumors are malignant, long-term cure and survival are not likely.  相似文献   
86.
87.
The oxidation of Fe-C alloys containing 0.5 and 1.0% C was studied in 1 atm O2 at 700° C. The oxidation rate is considerably slower than for pure Fe. The oxide scale formed is detached, multilayered, and overoxidized, containing little or no FeO. A thin film of graphite was identified at the metal-oxide interface by electron diffraction. It is proposed that the slow oxidation and abnormal scale are caused by a residue of graphite left at the metal surface from the oxidation of Fe3C. This inhibition of the oxidation of Fe by carbon at 700°C is in contrast to the stimulation observed at 500°C.  相似文献   
88.
Multifactorial index of cardiac risk in noncardiac surgical procedures   总被引:4,自引:0,他引:4  
To determine which preoperative factors might affect the development of cardiac complications after major noncardiac operations, we prospectively studied 1001 patients over 40 years of age. By multivariate discriminant analysis, we identified nine independent significant correlates of life-threatening and fatal cardiac complications: preoperative third heart sound or jugular venous distention; myocardial infarction in the preceding six months; more than five premature ventricular contractions per minute documented at any time before operation; rhythm other than sinus or presence of premature atrial contractions on preoperative electrocardiogram; age over 70 years; intraperitoneal, intrathoracic or aortic operation; emergency operation; important valvular aortic stenosis; and poor general medical condition. Patients could be separated into four classes of significantly different risk. Ten of the 19 postoperative cardiac fatalities occurred in the 18 patients at highest risk. If validated by prospective application, the multifactorial index may allow preoperative estimation of cardiac risk independent of direct surgical risk.  相似文献   
89.
90.
In this article, the authors respond to J. D. Cohen, K. O. Dunbar, D. M. Barch and T. S. Braver's (see record 1997-02838-005) comment on their target article (see record 1997-02838-004). The present article (a) takes issue with the characterization given by Cohen et al. of the authors' approach as a classical speed-of-processing account of Stroop effects, (b) discusses the value and relevance of other theoretical concepts, such as traditional accounts of working memory and parallel distributed processing (PDP) approaches to Stroop effects, (c) further examines the possibility that the differences the authors observed in Experiment 2 between normal participants' performance and that of participants with schizophrenia may have been due to distractor stimulus degradation, particularly for participants with schizophrenia, and (d) argues for the relevance of the prefrontal cortex, as well as other brain areas, in accounting for their results. The authors conclude with a final theoretical question. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号