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   1919篇
  免费   43篇
  国内免费   1篇
电工技术   24篇
综合类   4篇
化学工业   289篇
金属工艺   17篇
机械仪表   13篇
建筑科学   51篇
矿业工程   1篇
能源动力   19篇
轻工业   168篇
水利工程   3篇
石油天然气   4篇
无线电   75篇
一般工业技术   250篇
冶金工业   857篇
原子能技术   4篇
自动化技术   184篇
  2022年   10篇
  2021年   30篇
  2020年   24篇
  2019年   32篇
  2018年   25篇
  2017年   17篇
  2016年   38篇
  2015年   22篇
  2014年   36篇
  2013年   40篇
  2012年   64篇
  2011年   83篇
  2010年   39篇
  2009年   42篇
  2008年   43篇
  2007年   46篇
  2006年   48篇
  2005年   32篇
  2004年   29篇
  2003年   27篇
  2002年   57篇
  2001年   49篇
  2000年   37篇
  1999年   46篇
  1998年   267篇
  1997年   125篇
  1996年   86篇
  1995年   52篇
  1994年   47篇
  1993年   58篇
  1992年   26篇
  1991年   28篇
  1990年   26篇
  1989年   23篇
  1988年   26篇
  1987年   28篇
  1986年   25篇
  1985年   19篇
  1984年   13篇
  1983年   9篇
  1982年   10篇
  1981年   15篇
  1980年   8篇
  1979年   8篇
  1978年   10篇
  1977年   21篇
  1976年   60篇
  1975年   7篇
  1973年   6篇
  1970年   6篇
排序方式: 共有1963条查询结果,搜索用时 15 毫秒
1.
2.
Marrone  Mauricio  Lemke  Sascha  Kolbe  Lutz M. 《Scientometrics》2022,127(7):3857-3878
Scientometrics - Computer-assisted methods and tools can help researchers automate the coding process of literature reviews and accelerate the literature review process. However, existing...  相似文献   
3.
Abstract

Microalgae are unicellular microorganisms that can be rich in proteins and are therefore a valuable ingredient in different foods. So far microalgae are mainly utilized in foods in low concentrations as a whole-cell ingredient even though it is known that proteins extracted from microalgae can possibly posess various technofunctional properties, such as high protein solubility, emulsification, foaming, and gelation properties. The widespread usage of protein-rich ingredients obtained from microalgae is for the most part prevented by the high price of the biomass, the lack of efficient downstream processes, and the adverse taste. The aim of this review is to give insights into the fundamental properties of the growth and processing of microalgae, highlight the advantages of microalgae ingredients and show potential applications based on the technofunctional, nutritional and sensory properties that were reported. Moreover, the existing challenges and knowledge gaps that hinder the application of microalgal proteins in foods are discussed.  相似文献   
4.
BACKGROUND AND DESIGN: Giant aggressive keratoacanthoma is a rare destructive subset of keratoacanthoma that frequently involves the facial region, grows rapidly to a large size, and often recurs after surgical management. The effectiveness of ionizing radiation therapy was examined in a retrospective study involving 16 patients; 14 of the tumors had recurred after surgical therapy. RESULTS: All tumors resolved with satisfactory cosmetic results and without recurrence following a fractionated course of superficial radiation therapy. CONCLUSIONS: Radiation therapy is an effective therapeutic modality for giant aggressive keratoacanthomas.  相似文献   
5.
The percentage of long-term survivors after intensive chemotherapy and the outcome of MDS patients who achieve partial remission (PR) with intensive chemotherapy (IC) are not known. Between 1981 and 1996 we treated 99 patients with de novo MDS who had high-risk MDS or progression to AML, with IC. 41 (41%) achieved CR, 16 (16%) achieved partial remission (PR), 26 (26%) had failure, and 16 (16%) died in aplasia. Eight of the patients who achieved CR were autografted, three were allografted and the remaining cases received moderate consolidation chemotherapy. After IC, the 16 PR patients fulfilled the criteria for RA in 15 cases and CMML in one case. Median PR duration was 17 months, and three PR were > 3 years (39, 50+, 82+ months). Median actuarial survival of patients who achieved PR and CR was 18 months and 20 months from the onset of IC, respectively (difference not significant). Of the 71 patients treated before 1993, with sufficient follow-up, 10 (14%) had survived > 4 years (long-term survivors). Four of them were alive in first CR after 49+ to 110+ months and probably cured, two were alive in PR after 50+ and 82+ months and four had died after 49-78 months. Long-term survivors were characterized by a significantly higher incidence of RAEB-T at diagnosis, and with normal or favourable cytogenetic findings. In patients with RAEB-T at diagnosis included before 1993, 8/23 (35%) cases who had no unfavourable karyotype had survived > 4 years. Our findings suggest that MDS patients who achieve PR with IC, and not only those who achieve CR, can benefit from this type of treatment. The percentage of long-term survivors remains low, however, and is almost restricted to patients with RAEB-T at diagnosis and no unfavourable karyotype.  相似文献   
6.
7.
Enabling simulation interoperability   总被引:1,自引:0,他引:1  
Morse  K.L. Lightner  M. Little  R. Lutz  B. Scrudder  R. 《Computer》2006,39(1):115-117
Over the past years a series of architectures have addressed the need to link multiple simulations. These efforts have been driven primarily by the desire to reuse existing "best of breed" simulations in new combinations to avoid developing any single, monolithic architecture with the impossible goal of meeting all simulation needs. The US Department of Defense began developing the high level architecture (HLA) for distributed computer simulation systems. The high level architecture addresses the need to link multiple computer simulation systems. HLA separates the data model from the architecture's functions for exchanging information.  相似文献   
8.
The author proposes that many forms of memory distortion, including the progressive changes in recollection of a learning experience often observed over successive tests, are due to the same processes that yield veridical recollection in some circumstances and memory loss and recovery in others. In a framework for interpreting all of these aspects of memory, the author assumes that the objects and events of a learning experience are encoded in parallel in traces of their perceptual attributes, which are basic to recognition, and in traces of reactions made to the events during or following learning, which are basic to recall. Random perturbation of remembered attribute values in both types of traces over retention intervals is a pervasive cause of both loss and distortions of memory.  相似文献   
9.
Serotonin [5-hydroxytryptamine(5-HT)] in the paraventricular nucleus (PVN) of rats has a suppressive effect on feeding behavior and causes a selective decrease in carbohydrate ingestion, specifically at the onset of the natural (dark) feeding period. Studies conducted here provide further evidence for this phenomena, showing a similar dose-related decrease in carbohydrate ingestion at dark onset after PVN injection of 5-HT or of the agonists, d-norfenfluramine or fluoxetine, which act through endogenous 5-HT. To further characterize the effects of this indoleamine on the macrostructure of feeding, a computer-automated data acquisition system was used to analyze macronutrient feeding patterns in freely feeding animals maintained on the pure diets of protein, carbohydrate, and fat. Results indicate that PVN administration of 5-HT at dark onset decreases intake of the carbohydrate nutrient by decreasing meal size, feeding time, and feeding rate for this nutrient and increasing the satiating effect of carbohydrate. These effects, which occur specifically during the first meal after injection, are opposite those seen after peripheral administration of the 5-HT receptor antagonist, metergoline. This drug stimulates feeding through a selective increase in carbohydrate intake, characterized by an increase in meal size, percent composition, and feeding time for this nutrient and a decrease in the satiety ratio for carbohydrate. These results implicate the serotonergic system in the termination of carbohydrate-rich meals that are prevalent during the early hours of the natural feeding cycle.  相似文献   
10.
A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of asparate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by orf3, which is oriented in the opposite direction. Interruptions in the remaining open reading frames did not affect growth on glucose-minimal medium. No significant similarity to sequences in databases was found for orf1 and orf2. Orf3 contained extensive similarity to reading frames defined by E. coli yjiP, yjiQ, yhgA, and yafD. The function of these amino acid sequences is as yet undefined.  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