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   24450篇
  免费   2498篇
  国内免费   12篇
电工技术   1456篇
综合类   404篇
化学工业   10251篇
金属工艺   336篇
机械仪表   498篇
建筑科学   888篇
矿业工程   179篇
能源动力   319篇
轻工业   2633篇
水利工程   165篇
石油天然气   77篇
无线电   914篇
一般工业技术   4181篇
冶金工业   1418篇
原子能技术   86篇
自动化技术   3155篇
  2023年   709篇
  2022年   639篇
  2021年   1062篇
  2020年   841篇
  2019年   760篇
  2018年   779篇
  2017年   593篇
  2016年   882篇
  2015年   980篇
  2014年   1103篇
  2013年   1829篇
  2012年   916篇
  2011年   923篇
  2010年   1081篇
  2009年   1203篇
  2008年   773篇
  2007年   657篇
  2006年   503篇
  2005年   468篇
  2004年   376篇
  2003年   364篇
  2002年   227篇
  2001年   221篇
  1999年   197篇
  1998年   446篇
  1997年   318篇
  1996年   344篇
  1995年   278篇
  1994年   245篇
  1993年   319篇
  1992年   230篇
  1990年   188篇
  1989年   213篇
  1988年   181篇
  1987年   201篇
  1986年   219篇
  1985年   204篇
  1984年   198篇
  1983年   204篇
  1982年   194篇
  1981年   230篇
  1980年   188篇
  1979年   188篇
  1977年   172篇
  1976年   194篇
  1975年   231篇
  1974年   202篇
  1973年   381篇
  1972年   228篇
  1971年   159篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
PURPOSE: Pancreatic cancer is difficult to treat, with most patients surgically unresectable at the time of diagnosis. Radiotherapy and chemotherapy can offer palliation, but more effective therapy is needed. This trial evaluated the effects of an aggressive schedule of paclitaxel given with granulocyte colony-stimulating factor (G-CSF) to patients with advanced pancreatic cancer. PATIENTS AND METHODS: All patients were required to have a histologic diagnosis of pancreatic adenocarcinoma with measurable disease and no prior chemotherapy or radiation therapy. Patients had to have performance status of 0 to 2, pretreatment absolute granulocyte count > or = 1,500/microL, and platelet count greater than or equal to the institutional lower limit of normal. Following pretreatment with dexamethasone, diphenhydramine, and cimetidine, patients received paclitaxel at a dose of 250 mg/m2 by 24-hour infusion on day 1, repeated every 21 days. G-CSF was given at a dose of 5 microg/kg/d on days 3 to 18 or until two consecutive absolute neutrophil counts (ANCs) > or = 10,000/microL were obtained. Doses of paclitaxel were modified depending on nadir counts. RESULTS: Forty-five patients were entered onto this study, with six ineligible. For the 39 eligible patients, there was one complete response (CR) and two partial responses (PRs), five stable/no responses, 23 increasing disease, two early deaths, and six patients whose assessment was inadequate to determine response. The response rate was therefore three of 39 or 8% (95% confidence interval [CI], 2% to 21%). The median survival time for the 39 eligible patients was 5 months. The most common toxicities were anemia, leukopenia/granulocytopenia, malaise/fatigue, nausea/vomiting, alopecia, thrombocytopenia, paresthesias, and liver function abnormalities. There was one death due to sepsis. CONCLUSION: Single-agent paclitaxel in this dose and schedule has minimal activity in pancreatic adenocarcinoma patients.  相似文献   
82.
83.
Summary Plastic yielding of anisotropic metals can be either described by a macroscopic constitutive relation or assessed by means of a model which correlates single and polycrystal behaviors. The mathematical identification of the plastic work rate derived from the two approaches, for all strain rate tensors, leads to a fit of the polycrystal yield surface by an analytical function. When a quadratic from is assumed, the macroscopic anisotropy parameters become explicit functions of the texture coefficients. This identification method is applied to calculate yield surfaces andR-values of rolled and annealed steel sheets: theR-values and in general the flow rule, are more significantly modified by the fitting than the yield surface. Thus, it is worth extending the method to more general constitutive relations which may be given by the form of their work function: alternative forms of the work function for plastic materials are explored, especially in the bearing of convexity and homogeneity where quadratic forms have a distinct advantage. Finally, it is shown that the identification of the work function allows to express the phenomenological coefficients as analytical functions of the texture parameters for many forms of the work function; in the other cases, these coefficients may be obtained by linear or non-linear regression.  相似文献   
84.
85.
86.
87.
88.
89.
90.
QUEUE     
Ohne Zusammenfassung  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