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   2140篇
  免费   16篇
电工技术   16篇
化学工业   155篇
金属工艺   31篇
机械仪表   22篇
建筑科学   26篇
能源动力   15篇
轻工业   122篇
水利工程   31篇
石油天然气   1篇
无线电   85篇
一般工业技术   137篇
冶金工业   1361篇
原子能技术   21篇
自动化技术   133篇
  2021年   12篇
  2019年   8篇
  2018年   18篇
  2017年   10篇
  2016年   20篇
  2015年   7篇
  2014年   30篇
  2013年   51篇
  2012年   32篇
  2011年   39篇
  2010年   30篇
  2009年   24篇
  2008年   32篇
  2007年   43篇
  2006年   42篇
  2005年   35篇
  2004年   36篇
  2003年   26篇
  2002年   34篇
  2001年   25篇
  2000年   29篇
  1999年   63篇
  1998年   329篇
  1997年   218篇
  1996年   165篇
  1995年   92篇
  1994年   76篇
  1993年   84篇
  1992年   19篇
  1991年   27篇
  1990年   35篇
  1989年   29篇
  1988年   27篇
  1987年   22篇
  1986年   25篇
  1985年   31篇
  1984年   8篇
  1983年   17篇
  1982年   17篇
  1981年   24篇
  1980年   22篇
  1979年   11篇
  1978年   17篇
  1977年   32篇
  1976年   81篇
  1975年   19篇
  1974年   13篇
  1973年   7篇
  1972年   8篇
  1970年   7篇
排序方式: 共有2156条查询结果,搜索用时 15 毫秒
1.
PURPOSE: We designed a phase I-II trial of three active agents, paclitaxel, ifosfamide, and vinorelbine, in advanced non-small-cell lung cancer (NSCLC) to: 1) define the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of paclitaxel with filgrastim (G-CSF) support; and 2) determine the overall response rate and median survival of patients treated on this regimen. PATIENTS AND METHODS: We treated cohorts of patients with stage IIIB or IV NSCLC with ifosfamide 1.2-1.6 g/m2/day x 3 and vinorelbine 20-25 mg/m2/day x 3 and escalating doses of paclitaxel at 100-175 mg/m2 on day 2 with G-CSF support on a 21-day cycle. One prior experimental single-agent chemotherapy regimen was allowed. RESULTS: Fifty-six patients, were enrolled on this trial: 27 on the phase I portion of the study and an additional 29 at the recommended phase II dose (RPTD). Thirteen patients had received prior chemotherapy. Paclitaxel doses of 175 mg/m2 and 150 mg/m2 produced dose-limiting myelosuppression, and the RPTD was determined to be paclitaxel 135 mg/m2 with ifosfamide 1.2 g/m2/day on days 1-3 and vinorelbine 20 mg/m2/ day on days 1-3 with G-CSF support. The overall response rate was 18%, with a median survival of 6.1 months. Six of 35 patients (17%) treated at the RPTD achieved a partial response to therapy. Grade IV neutropenia was observed in 19 of 35 patients at this dose, with eight patients suffering febrile neutropenia. CONCLUSIONS: This non-cisplatin-containing three-drug regimen has substantial toxicity and low activity in advanced NSCLC, and does not seem to improve on prior regimens. It is unclear whether the lack of efficacy relates to an antagonistic reaction between the specific drugs, administration schedule, or to subtherapeutic doses of the individual agents.  相似文献   
2.
3.
Comments on the argument of L. T. Hoshmand and D. E. Polkinghorn (see record 1992-21300-001) that psychological practice should inform science to the same degree that science informs practice. Based on a survey of 121 faculty members in programs accredited by the American Psychological Association, 65% reported practice activity. The authors agree that the problem involves a much more complex integrative task that goes beyond simply recognizing knowledge gained in practice settings as valid. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
4.
5.
6.
The fabrication using silicon micromachining and characterization of an acoustic Lamb wave actuator is presented. The intended use of the device is for mass transport and sensor applications. The device consists of dual interdigitated transducers patterned on a thin-film composite membrane of silicon nitride, platinum, and a sol-gel-derived piezoelectric ceramic (PZT) thin film. The acoustic properties of the device are presented along with preliminary applications to mechanical transport and liquid delivery systems. Improved acoustic signals and improved mass transport are achieved with PZT over present Lamb wave devices utilizing ZnO or AlN as the piezoelectric transducer  相似文献   
7.
Psoralens and sunlight have been used by the Egyptians and Indians for hundreds of years for treating vitiligo. The combination of oral psoralens and artificial ultraviolet A (PUVA) therapy was approved for managing severe psoriasis by the Food and Drug Administration in 1982. Since then, PUVA therapy has been an effective modality for treating many cutaneous conditions (psoriasis, atopic dermatitis, vitiligo, and mycosis fungoides). However, proper knowledge and administration of PUVA therapy are vital to treatment success and reducing side effects.  相似文献   
8.
Poor spellers in 2nd grade (n?=?128) participated in 24 20-min sessions that included (a) direct instruction in the alphabet principle (most frequent phoneme-spelling connections); (b) modeling of different approaches, singly and in combination, for developing connections between spoken and written words for 48 words ordered by sound-spelling predictability; and (c) practice in composing. Results of this multilayered intervention showed that (a) more than 1 way of developing sound-spelling connections is effective in teaching spelling but that after training in the alphabet principle, combining whole word and onset-rime training is most effective in achieving transfer of the alphabet principle across word contexts; (b) functional spelling units of not only a single letter but also 2 or more letters are important in beginning spelling; and (c) training in spelling transfers to composition and word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Osteomyelitis in uncommon locations can present unusual diagnostic difficulties. A patient with primary sternal osteomyelitis who presented with pain over the right supraclavicular area and a radiologic picture of a pleural-based right upper lung mass is discussed. A triple-phase bone scan was consistent with the diagnosis, and a needle aspiration of the mass revealed a staphylococcal abscess. Percutaneous drainage of the contiguous abscess and a prolonged course of antibiotic therapy cured the infection.  相似文献   
10.
Dimensionless material balance equations describing an uninhibited enzyme hydrolysis process in a semi-batch reactor (i.e. fed-batch reactor) are formulated; numerical solution of these equations provided concentration profiles of the enzyme-substrate complex by using published kinetic parameters. The unrestricted values obtained are compared with estimates based separately on the reaction steady state and stationary state assumptions. Results are discussed in terms of the enzyme/substrate inventory used and it is found that the reaction steady state is a satisfactory approximation only when this ratio is sufficiently small. The stationary state may be a better approximation at other values, particularly when enzyme is added to substrate or when an empty tank is being filled. Reaction yields from semi-batch and batch operations are compared. Processing takes longer in the semi-batch operations and complete conversions are only practical in this mode when enzyme is added to substrate.  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