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   39665篇
  免费   3788篇
  国内免费   1680篇
电工技术   1313篇
技术理论   1篇
综合类   2923篇
化学工业   10874篇
金属工艺   2056篇
机械仪表   1561篇
建筑科学   3272篇
矿业工程   1304篇
能源动力   2266篇
轻工业   3582篇
水利工程   1819篇
石油天然气   1949篇
武器工业   226篇
无线电   1522篇
一般工业技术   4879篇
冶金工业   2332篇
原子能技术   337篇
自动化技术   2917篇
  2024年   236篇
  2023年   665篇
  2022年   1249篇
  2021年   1386篇
  2020年   1388篇
  2019年   1177篇
  2018年   1128篇
  2017年   1306篇
  2016年   1396篇
  2015年   1403篇
  2014年   2092篇
  2013年   2442篇
  2012年   2666篇
  2011年   3085篇
  2010年   2297篇
  2009年   2377篇
  2008年   2050篇
  2007年   2605篇
  2006年   2382篇
  2005年   2080篇
  2004年   1734篇
  2003年   1470篇
  2002年   1231篇
  2001年   1000篇
  2000年   811篇
  1999年   658篇
  1998年   539篇
  1997年   446篇
  1996年   317篇
  1995年   279篇
  1994年   229篇
  1993年   168篇
  1992年   162篇
  1991年   109篇
  1990年   78篇
  1989年   73篇
  1988年   65篇
  1987年   42篇
  1986年   44篇
  1985年   32篇
  1984年   26篇
  1983年   26篇
  1982年   26篇
  1981年   9篇
  1980年   9篇
  1979年   10篇
  1964年   10篇
  1961年   9篇
  1957年   13篇
  1951年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Reviews the book, Emotion-focused therapy: Coaching clients to work through their feelings by Leslie S. Greenberg (see record 2002-00066-000). This book was written for both novice therapists who have had little experience working with emotions in treatment, as well as for experienced therapists looking to systematize their understanding of how emotional change works. The book is divided into four parts. Part I examines the nature and function of emotions. Part II examines the first part of emotional coaching--arriving at emotion. Part III examines the second part of emotional coaching--leaving emotion. Finally, Part IV examines the application of emotion-focused therapy to the problems of living, in the context of individuals, couples therapy, and parenting. This book offers a wealth of therapeutic techniques and theoretical principles about the process of change. As such, it is an important and natural companion to seminal works in cognitive behaviour therapy and interpersonal therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
72.
73.
叙述了目前加油站在实行按任意温度下的体积交接,由于未考虑油品体积随温度、压力、密度的变化,出现了零售损耗很大的问题。建议加油站在现阶段采用“准标准体积”交接;在由体积转换为质量计算加油站损溢时,使用油库当月发出的平均密度;当财会核销损溢时,不使用盘存的体积和固定密度进行计算的方法,而使用实际盘点的质量数,以真实反映加油站的当期损溢。  相似文献   
74.
应用比较几何的方法研究了完备非紧且具有特定曲率条件的黎曼流形,证明了在一定Pinching条件限制下,流形具有有限拓扑型或者微分同胚于R^n。  相似文献   
75.
The vicissitudes of the Israeli-Palestinian peace process since 1967 are analyzed using attitudes and related concepts where relevant. The 1967 war returned the two peoples' zero-sum conflict around national identity to its origin as a conflict within the land both peoples claim. Gradually, new attitudes evolved regarding the necessity and possibility of negotiations toward a two-state solution based on mutual recognition, which became the building stones of the 1993 Oslo agreement. Lacking a commitment to a final outcome, the Oslo-based peace process was hampered by reserve options, which increased avoidance at the expense of approach tendencies as the parties moved toward a final agreement. The resulting breakdown of the process in 2000 produced clashing narratives, reflecting different anchors for judgment and classical mirror images. Public support for violence increased, even as public opinion continued to favor a negotiated two-state solution. Reviving the peace process requires mutual reassurance about the availability of a partner for negotiating a principled peace based on a historic compromise that meets the basic needs and validates the identities of both peoples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
76.
对现场生产的ZLl01合金铸件材质进行了全面分析,针对存在的产品成分不准,变质效果不好,力学性能不合格的问题,通过改进合金的锶变质工艺和热处理工艺,改善了合金的组织和性能,达到了对材料的成分、性能的各项要求。  相似文献   
77.
钛合金植入物材料的表面改性研究进展   总被引:1,自引:0,他引:1  
简介了钛合金植入物材料的开发及表面改性技术。  相似文献   
78.
The density of liquid Ni- Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni- Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni- Ta binary alloys increases with the increase of temperature ancl tantalum concentration.  相似文献   
79.
To investigate the efficiency of clodronate modifying HA bioceramics,and to evaluate the effect of clodronate modifying HA bioceramics on the cells in vitro,clodronate modified the porous HA bioceramics for bone scaffold by chelation .The outermost layer of the specimens was analyzd by XPS and FI-IR ,The depth profile was investigated by the argon-ion sputtering method.The cell culture test was conducted using MC3T3-E1 osteoblastic cells,The cells were inoculated and cultured on the scaffolds.Morphological observation of the cells,MTT test and ALP activity test evaluated the cell attachment ,proliferation and activity on the scaffolds.The cell culture test in cell quantity and morphology indicated active proliferation of the cells on the scaffolds.The ALP activity of the cells cultured for 3d and 7d on clodronate-HA bioceramics was slightly higher than that on HA bioceramics ,but the difference was not signifcant,This result indicated that clodronate-HA bioeramics had favorable cytocompatibility to be used as bone scaffold with potential ability to improve asteogensis.  相似文献   
80.
在前人研究的基础之上,归纳总结了聚合物复合材料填充剂的种类,综述了对其进行表面改性的目的、条件、方法、工艺以及对改性结果的表征等。文章还分析了影响填充聚合物复合材料性能的因素,指出了今后发展的方向。  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