全文获取类型
收费全文 | 1052篇 |
免费 | 16篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 56篇 |
综合类 | 3篇 |
化学工业 | 193篇 |
金属工艺 | 34篇 |
机械仪表 | 24篇 |
建筑科学 | 24篇 |
能源动力 | 32篇 |
轻工业 | 48篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 106篇 |
一般工业技术 | 136篇 |
冶金工业 | 274篇 |
原子能技术 | 59篇 |
自动化技术 | 81篇 |
出版年
2022年 | 5篇 |
2021年 | 19篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 19篇 |
2013年 | 32篇 |
2012年 | 26篇 |
2011年 | 41篇 |
2010年 | 33篇 |
2009年 | 46篇 |
2008年 | 43篇 |
2007年 | 29篇 |
2006年 | 24篇 |
2005年 | 29篇 |
2004年 | 26篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 28篇 |
2000年 | 27篇 |
1999年 | 28篇 |
1998年 | 94篇 |
1997年 | 62篇 |
1996年 | 45篇 |
1995年 | 45篇 |
1994年 | 34篇 |
1993年 | 26篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 15篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1973年 | 6篇 |
1969年 | 4篇 |
排序方式: 共有1074条查询结果,搜索用时 31 毫秒
1.
A. Nakano T. Shimazaki M. Sekiya H. Shiozawa K. Ohtsuka A. Aoyagi T. Iwakiri Z. Mikami M. Sato Y. Sugino K. Kinoshita T. Matsuoka T. Imamura Y. Takayama K. Yamamoto 《International Journal of Hydrogen Energy》2021,46(29):15649-15659
Monitoring the temperature in liquid hydrogen (LH2) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa. 相似文献
2.
Kazuo Tsubota Stephen C. Pflugfelder Zuguo Liu Christophe Baudouin Hyo Myung Kim Elisabeth M. Messmer Friedrich Kruse Lingyi Liang Jimena Tatiana Carreno-Galeano Maurizio Rolando Norihiko Yokoi Shigeru Kinoshita Reza Dana 《International journal of molecular sciences》2020,21(23)
Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint. 相似文献
3.
T Murate K Yamashita H Ohashi Y Kagami K Tsushita T Kinoshita T Hotta H Saito S Yoshida KJ Mori 《Canadian Metallurgical Quarterly》1993,21(1):169-176
The erythroid-potentiating activity (EPA) of the tissue inhibitor of metalloproteinase-1 (TIMP-1) was re-examined using ELM-I-1-3, a mouse erythroleukemia cell line, which responded well to erythropoietin. Depletion of pre-existing TIMP-1 from fetal calf serum in culture medium using monoclonal antibody suppressed erythropoietin-induced differentiation as measured by the induction of hemoglobin, commitment assay and globin mRNAs. The removal of TIMP-1 also suppressed the proliferation of ELM-I-1-3 as measured by cell number and de novo DNA synthesis. These changes were reversed by the addition of purified TIMP-1 to the culture medium. Anti-TIMP-1 antibody also blocked both hexamethylene bisacetamide (HMBA)-induced erythroid differentiation and the proliferation of both ELM-I-1-3 and Friend erythroleukemia cells. Considering previous reports analyzing the chemical induction of Friend mouse erythroleukemia cell differentiation, our results suggest that erythropoietin- or HMBA-induced erythroid differentiation might also be coupled with cell proliferation. Our 3H thymidine-uptake experiment shows that TIMP-1 removal was also effective in the inhibition of cell growth of various other cell lines in addition to erythroleukemia cell lines. These results suggest that EPA action of TIMP-1 on erythroid leukemia cell lines is closely related to its activity to promote the cell growth of various cell lines and cells including erythroleukemia cell lines. 相似文献
4.
H Kazunaga H Suwaki K Ameno H Kinoshita I Ijiri 《Canadian Metallurgical Quarterly》1994,29(5):429-437
We report here the comparison of urinary dolichols/creatine (D/Cr) concentration ratios in male non-drinkers, moderate-drinkers and heavy drinkers at admission and during hospitalization, and also discuss its usefulness as a biological marker for alcohol abuse. Urine samples were collected from the following four experimental groups: non-(male and female) and moderate-drinker (male) volunteers, and alcoholic heavy-drinking patients (male) at admission for psychiatric treatment and after 9-15 days hospitalization (informed consent was obtained). Urinary dolichols were determined by high performance liquid chromatography after BondElutC18 (500 mg) extraction. Due to significant differences in urinary D/Cr concentrations between male and female groups in non-drinkers and because the heavy-drinkers available for this study were exclusively male, comparison of the value of urinary D/Cr concentration ratios was subsequently limited to male only. There were no statistical differences in urinary D/Cr concentrations in the male among non-drinkers, moderate-drinkers and heavy-drinkers at admission. The accuracy of urinary D/Cr as a biological marker for alcohol abuse, calculated using the mean +/- 2 s.d. in non- and moderate-drinkers as the normal range, is only 33.3% in heavy-drinkers at admission, while their value of gamma-GTP in serum was 88.3%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
Motofumi Suzuki Kohei Kinoshita Shinji Jomori Hidehiko Harada Kaoru Nakajima Kenji Kimura 《Thin solid films》2007,515(22):8281-8284
The initial stage of iron silicide formation is investigated by high-resolution Rutherford backscattering spectroscopy. During the Fe deposition on Si(001) at 470 °C, the formation of FeSi2 is confirmed by the surface peak analysis. Initially, FeSi2 grows epitaxially so that one of the major crystallographic axes is parallel to the <111> axis of the Si substrate. With increasing Fe deposition, the deviation between the major crystallographic axis of the silicide region and Si<111> increases although the electron diffraction pattern is independent of the amount of Fe deposition. Therefore, the subsurface crystallographic structure of iron silicide is transformed from a cubic-like to a low-symmetry structure. 相似文献
6.
7.
We investigated intestinal ethanol absorption in rats pretreated with saline, cyanamide, 4-methylpyrazole and cyanamide + 4-methylpyrazole. The value of the absorption rate constant in the cyanamide-pretreated group with high acetaldehyde levels was the lowest among the four groups, but there were no significant differences among the remaining groups. We found that high acetaldehyde concentration itself clearly reduces intestinal ethanol absorption. 相似文献
8.
This paper presents a partial scan algorithm, calledPARES (PartialscanAlgorithm based onREduced Scan shift), for designing partial scan circuits. PARES is based on the reduced scan shift that has been previously proposed for generating short test sequences for full scan circuits. In the reduced scan shift method, one determines proch FFs must be controlled and observed for each test vector. According to the results of similar analysis, PARES selects these FFs that must be controlled or observed for a large number of test vectors, as scanned FFs. Short test sequences are generated by reducing scan shift operations using a static test compaction method. To minimize the loss of fault coverage, the order of test vectors is so determined that the unscanned FFs are in the state required by the next test vector. If there are any faults undetected yet by a test sequence derived from the test vectors, then PARES uses a sequential circuit test generator to detect the faults. Experimental results for ISCAS'89 benchmark circuits are given to demonstrate the effectiveness of PARES. 相似文献
9.
The surface chemical states of the perovskite-type compounds, strontium doped lanthanum cobalt oxides (La1?x Sr x CoO3), have been investigated using X-ray photoelectron spectroscopy (XPS). Catalytic oxidations of both methane and CO have also been investigated using flow methods. The chemical composition of the surface of La1?x Sr x CoO3 was very different from that in the bulk, which was measured by X-ray fluorescence spectroscopy (XRFS). The catalytic activity of La1?x Sr x CoO3 increased with an increase in the quantity of cobalt atoms on the surface. 相似文献
10.
Far-infrared reflection spectra of dielectric ceramics, BaSm2 Ti5 O14 , BaTi4 O9 , and some pcrovskites such as Ba(Zn1/3 Nb2/3 )O3 , have been measured at room temperature using a Fourier transform infrared spectrometer in order to investigate the effect of the crystal structure on the dielectric properties. As for perovskites, Sr(Zn1/3 Nb2/3 )O3 and Sr(Mg1/3 Nb2/3 )O3 , in which B site ions are ordered, were also measured. Reflectance data were analyzed by means of a factorized form of dielectric functions instead of the classical dispersion theory, and all of the spectra were well fitted. The values of dielectric constants and tan δ calculated from the reflectance data were in good agreement with resonant cavity measurements at 5 GHz. Furthermore, results of this study have shown that the main contribution to the microwave dielectric properties is caused by low-frequency optically active modes located at 50 to about 300 cm−1 , and for perovskite structures it is suggested that the ordering of B site ions is significant in obtaining low dielectric losses. 相似文献