全文获取类型
收费全文 | 12960篇 |
免费 | 932篇 |
国内免费 | 115篇 |
专业分类
电工技术 | 237篇 |
综合类 | 48篇 |
化学工业 | 3569篇 |
金属工艺 | 296篇 |
机械仪表 | 500篇 |
建筑科学 | 443篇 |
矿业工程 | 30篇 |
能源动力 | 867篇 |
轻工业 | 1197篇 |
水利工程 | 228篇 |
石油天然气 | 199篇 |
武器工业 | 5篇 |
无线电 | 1332篇 |
一般工业技术 | 2229篇 |
冶金工业 | 415篇 |
原子能技术 | 108篇 |
自动化技术 | 2304篇 |
出版年
2024年 | 47篇 |
2023年 | 250篇 |
2022年 | 501篇 |
2021年 | 789篇 |
2020年 | 701篇 |
2019年 | 857篇 |
2018年 | 996篇 |
2017年 | 896篇 |
2016年 | 918篇 |
2015年 | 548篇 |
2014年 | 883篇 |
2013年 | 1399篇 |
2012年 | 850篇 |
2011年 | 972篇 |
2010年 | 627篇 |
2009年 | 558篇 |
2008年 | 355篇 |
2007年 | 255篇 |
2006年 | 240篇 |
2005年 | 159篇 |
2004年 | 157篇 |
2003年 | 102篇 |
2002年 | 109篇 |
2001年 | 53篇 |
2000年 | 51篇 |
1999年 | 43篇 |
1998年 | 88篇 |
1997年 | 56篇 |
1996年 | 63篇 |
1995年 | 48篇 |
1994年 | 37篇 |
1993年 | 42篇 |
1992年 | 34篇 |
1991年 | 35篇 |
1990年 | 30篇 |
1989年 | 30篇 |
1988年 | 20篇 |
1987年 | 20篇 |
1986年 | 14篇 |
1985年 | 19篇 |
1984年 | 24篇 |
1983年 | 21篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1973年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Cerebral microbleeds and cognitive decline in a hemodialysis patient: Case report and review of literature 下载免费PDF全文
Lin Li Mark Fisher Wei‐Ling Lau Hamid Moradi Alexander Cheung Gaby Thai Jason Handwerker Kamyar Kalantar‐Zadeh 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(3):E1-E7
Cerebral microbleeds (CMBs) are small hemosiderin deposits indicative of prior cerebral microscopic hemorrhage and previously thought to be clinically silent. Recent population‐based cross‐sectional studies and prospective longitudinal cohort studies have revealed association between CMB and cognitive dysfunction. In the general population, CMBs are associated with age, hypertension, and cerebral amyloid angiopathy. In the chronic kidney disease (CKD) population, diminished estimated glomerular filtration rate has been found to be an independent risk factor for CMB, raising the possibility that a uremic milieu may predispose to microbleeds. In the end‐stage renal disease (ESRD) population on hemodialysis, the incidence of microbleeds is significantly higher compared with a control group without history of CKD or stroke. We present an ESRD patient on chronic hemodialysis with a history of gradual cognitive decline and progressive CMBs. Through this case and literature review, we illustrate the need to develop detection and prediction models to treat this frequent development in ESRD patients. 相似文献
2.
3.
Hassan Hajjaj Gerard Goma Jean M. François 《International Journal of Food Science & Technology》2015,50(8):1731-1736
In submerged cultures performed in chemically defined fermentation medium containing glucose and glutamate, the growth and production of water‐soluble red pigments and citrinin by the filamentous fungus Monascus ruber were studied under various carbon/nitrogen (C/N) ratios. The specific production of the red pigments was optimal at a glucose/glutamate ratio of about 10 and then steadily decreased at higher C/N ratio. In contrast, the production of the mycotoxin increased with increased C/N with an optimum in the range of 30–45. In a fed‐batch mode, it was also found that the production of pigments was not favoured in fed‐batch mode by feeding the medium with glucose while keeping the C/N ratio lower than 10. This low production likely resulted from concurrent high accumulation of L‐malic acid that was reported to inhibit this production. In contrast, this mode of cultivation was rather favourable for the production of the mycotoxin. 相似文献
4.
5.
6.
A cell vertex finite volume method for the solution of steady compressible turbulent flow problems on unstructured hybrid
meshes of tetrahedra, prisms, pyramids and hexahedra is described. These hybrid meshes are constructed by firstly discretising
the computational domain using tetrahedral elements and then by merging certain tetrahedra. A one equation turbulence model
is employed and the solution of the steady flow equations is obtained by explicit relaxation. The solution process is accelerated
by the addition of a multigrid method, in which the coarse meshes are generated by agglomeration, and by parallelisation.
The approach is shown to be effective for the simulation of a number of 3D flows of current practical interest.
Sponsored by The Research Council of Norway, project number 125676/410
Dedicated to the memory of Prof. Mike Crisfield, a respected colleague 相似文献
7.
8.
A stochastic model for local disturbances, particularly for a temporal harmonic with random modulations in amplitude and/or phase, is proposed in this paper. Results for the second moment responses of a linear single-degree-of-freedom system to this type of stochastic loading demonstrate a significant change in response characteristics due to a small uncertainty. A local phenomenon may last much longer and resonance may be smeared to a broad range. Integrated with wavelet transform, the proposed approach may be used to model a random process with non-stationary frequency content. Especially, it can be effectively used for Monte Carlo simulation to generate large size of samples that have similar characteristics in time and frequency domains as a pre-selected mother sample has. The technique has a great potential for the case where uncertainty study is warranted but the available samples are limited. 相似文献
9.
ABSTRACT: The objective of this work was to observe the microstructure of feta cheese using confocal scanning laser microscopy. Low fat cheese and cheese containing capsule-producing cultures were made. The protein network was observed using the reflectance mode of the confocal microscope. Fat was stained by Nile red dye diluted with whey. More even distribution of fat with a larger number of smaller globules was observed in cheese made with noncapsule-forming culture compared to that made with the capsule-forming culture. Nonfat cheese had compact structure when made with noncapsule-forming culture which contrasted with the open structure observed in cheese made with the capsule-forming culture 相似文献
10.
ME Sutherlin I Nishimori T Caffrey EP Bennett H Hassan U Mandel D Mack T Iwamura H Clausen MA Hollingsworth 《Canadian Metallurgical Quarterly》1997,57(21):4744-4748
The levels of mRNA expression of three UDP-N-acetyl-alpha-D-galactosamine:polypeptide GalNAc N-acetylgalactosaminyltransferases (GalNAc-transferases) were quantified for human adenocarcinoma cell lines from pancreas, colon, stomach, and breast. Two of the GalNAc-transferases, GalNAc-T1 and GalNAc-T2, were expressed constitutively and at low levels in most or all cell lines examined. A third GalNAc-transferase, GalNAc-T3, was differentially expressed. Well-differentiated adenocarcinoma cell lines expressed high levels and moderately differentiated cell lines expressed lower levels of GalNAc-T3. Cell lines classified as poorly differentiated failed to express GalNAc-T3 mRNA at levels that could be detected by Northern blot analysis. Differential expression of the GalNAc-T3 protein was confirmed in these cell lines by Western blotting. We propose that glycosylation in tumor cell lines may be regulated in part by differential expression of GalNAc-transferases, and we suggest that GalNAc-T3 gene expression may be a molecular indicator of differentiated adenocarcinoma. 相似文献