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   2068篇
  免费   76篇
  国内免费   7篇
电工技术   141篇
综合类   3篇
化学工业   644篇
金属工艺   72篇
机械仪表   61篇
建筑科学   64篇
能源动力   103篇
轻工业   226篇
水利工程   3篇
石油天然气   6篇
武器工业   2篇
无线电   106篇
一般工业技术   398篇
冶金工业   42篇
原子能技术   59篇
自动化技术   221篇
  2023年   9篇
  2022年   29篇
  2021年   59篇
  2020年   25篇
  2019年   28篇
  2018年   36篇
  2017年   38篇
  2016年   57篇
  2015年   34篇
  2014年   76篇
  2013年   147篇
  2012年   120篇
  2011年   132篇
  2010年   116篇
  2009年   131篇
  2008年   124篇
  2007年   105篇
  2006年   89篇
  2005年   80篇
  2004年   59篇
  2003年   45篇
  2002年   59篇
  2001年   37篇
  2000年   42篇
  1999年   30篇
  1998年   44篇
  1997年   31篇
  1996年   41篇
  1995年   29篇
  1994年   29篇
  1993年   31篇
  1992年   23篇
  1991年   21篇
  1990年   18篇
  1989年   20篇
  1988年   16篇
  1987年   10篇
  1986年   18篇
  1985年   18篇
  1984年   16篇
  1983年   12篇
  1982年   8篇
  1981年   10篇
  1980年   9篇
  1979年   7篇
  1978年   3篇
  1977年   12篇
  1975年   4篇
  1972年   3篇
  1971年   2篇
排序方式: 共有2151条查询结果,搜索用时 15 毫秒
71.
This paper presents the silicon based on-chip antenna using a LC resonator. The proposed antenna consists of a stacked capacitor and a spiral inductor on silicon substrate. The spiral inductor structure without underpass was proposed for improvement the performance of the silicon based-antenna. The resonant frequency of the fabricated antenna was measured as 465 MHz. Its return loss was 23.4 dB at resonant frequency. The antenna has a gain of ?35.75 dBi due to small size and silicon substrate. However, the fabricated antenna has good performance in the near-field.  相似文献   
72.
Resilience is a concept which presents the strength of mind necessary to adopt the difficulties and to recover from negative psychological state. The assessment for resilience has been assessed by using interview and questionnaire which depend on subjectivity of participants. Though the objective assessment for resilience is expected to advance the biofeedback treatment, neither effective method nor instrument have been developed. Then this study focuses on the pliability as one of aspects of resilience and experimentally verifies whether it becomes a novel index for resilience or not.  相似文献   
73.
Obesity-related metabolic abnormalities, including adipokine imbalance and chronic inflammation, are involved in liver carcinogenesis. Chemerin, a novel adipokine, plays a critical role in adipogenesis, energy metabolism, and inflammation. We evaluated the impact of serum chemerin levels on liver functional reserves in hepatocellular carcinoma (HCC) patients and on the recurrence and prognosis of HCC. This study included 44 patients with any stage of HCC who underwent curative treatment at Gifu Municipal Hospital (Gifu, Japan) between 2006 and 2007. Recurrence-free survival and overall survival were estimated using the Kaplan-Meier method. Serum albumin levels (Pearson’s correlation coefficient; r = 0.3110, p = 0.0399), platelet counts (r = 0.4159, p = 0.0050), and prothrombin times (r = 0.3775, p = 0.0115) were significantly correlated with serum chemerin levels in patients with HCC, and they were inversely correlated with Child-Pugh scores (r = −0.3732, p = 0.0126), serum alanine aminotransferase levels (r = −0.3864, p = 0.0105), and total bilirubin levels (r = −0.4023, p = 0.0068). Among these variables, a multiple comparison test identified that platelet counts and total bilirubin levels were associated with serum chemerin levels (p < 0.0083). No significant correlation was found between serum chemerin levels and recurrence-free survival (p = 0.3691) or overall survival (p = 0.7916). In HCC patients, serum chemerin concentrations were correlated with liver functional reserves and platelet counts, but not with recurrence or prognosis.  相似文献   
74.
Cachexia is a multifactorial syndrome characterized by muscle loss that cannot be reversed by conventional nutritional support. To uncover the molecular basis underlying the onset of cancer cachectic muscle wasting and establish an effective intervention against muscle loss, we used a cancer cachectic mouse model and examined the effects of aerobic exercise. Aerobic exercise successfully suppressed muscle atrophy and activated adiponectin signaling. Next, a cellular model for cancer cachectic muscle atrophy using C2C12 myotubes was prepared by treating myotubes with a conditioned medium from a culture of colon-26 cancer cells. Treatment of the atrophic myotubes with recombinant adiponectin was protective against the thinning of cells through the increased production of p-mTOR and suppression of LC3-II. Altogether, these findings suggest that the activation of adiponectin signaling could be part of the molecular mechanisms by which aerobic exercise ameliorates cancer cachexia-induced muscle wasting.  相似文献   
75.
The lipolytic and proteolytic activity of Penicillium camemberti PC TT033 and Penicillium roqueforti PR G3, cultured on the whey solids or simulated cheese media, were compared under several pH reaction conditions. Lipolytic activity was higher when both strains had been cultured on the whey medium than on the simulated cheese medium, whereas proteolytic activity was less influenced by the culture medium. The relationship between the reaction pH and these enzyme activities was dependent on the culture medium, which suggested that the expression level and balance of isozyme rely on the culture substrate.  相似文献   
76.
TGR5, a G-protein-coupled receptor (GPCR), plays an important role in several physiological functions. TGR5 activation through bile acids induces an increase in energy expenditure. Therefore, synthetic TGR5 ligands could be useful for the treatment of obesity or dyslipidemia. In this study, we designed and synthesized a set of TGR5 ligands with a 5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene (TMN) skeleton, and evaluated their TGR5 agonistic activity. We also investigated the selectivity of the synthesized compounds for TGR5 relative to the farnesoid X receptor (FXR) and retinoic acid receptor (RAR). Our results show that compound 4 b [N-(2-chlorophenyl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenecarboxamide] exhibited potent TGR5 agonist activity with an IC50 value of 8.4 nM without significant cytotoxicity. In addition, compound 4 b showed only slight agonistic activity toward FXR and RAR at 1 μM treatment. These data indicate that compound 4 b is a selective TGR5 agonist, and could be a promising therapeutic agent for dyslipidemia.  相似文献   
77.
High-resolution melting (HRM) analysis has been improved and applied for the first time to quantitative analysis of enzymatic reactions. By using the relative ratios of peak intensities of substrates and products, the quantitativity of conventional HRM analysis has been improved to allow detailed kinetic analysis. As an example, the ligation of sticky ends through the action of T4 DNA ligase has been kinetically analyzed, with comprehensive data on substrate specificity and other properties having been obtained. For the first time, the kinetic parameters (kobs and apparent Km) of sticky-end ligation were obtained for both fully matched and mismatched sticky ends. The effect of ATP concentration on sticky-end ligation was also investigated. The improved HRM method should also be applicable to versatile DNA-transforming enzymes, because the only requirement is that the products have Tm values different enough from the substrates.  相似文献   
78.
79.
Tomoya Enokido  Makoto Takizawa 《Computing》2013,95(10-11):1019-1037
In energy-aware information systems, it is critical to discuss how to select a server for each request from clients in order to not only achieve performance objectives but also reduce the total power consumption of a system. In order to design and evaluate the server selection algorithm, it is critical to define the power consumption model of a server to perform processes. In our previous studies, the transmission power consumption (TPC) model of a server is proposed to perform transmission processes. In the TPC model, the electric power consumption of cooling devices is assumed to be constant. Cooling devices like fans consume the electric power in a server. Thus, the total power consumption of a server depends on not only computation and communication devices but also cooling devices. In this paper, we propose the extended TPC (ETPC) model to take into account the power consumption of cooling devices. We validate the TPC and ETPC models by measuring the power consumption and transmission time of a server.  相似文献   
80.
Surface modification of diamond-like carbon (DLC) film was performed using a hyperthermal atomic fluorine beam on the purpose of production of hydrophobic surface by maintaining the high hardness of DLC film. By the irradiation of atomic fluorine beam of a 1.0 × 1020 atoms/cm2, the contact angle of a water drop against the DLC surface increased from 73° to 111°. The formation of CF3, CF2 and CF bonding on the modified DLC surface was confirmed from the measurements of X-ray photoelectron spectra and near-edge X-ray absorption fine structure spectra. Irradiation of hyperthermal atomic fluorine beam was concluded to produce insulator fluorine-terminated DLC film, which has high F content on the surface, by the taking of the use of neutral atomic beam as a fluorine source.  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