全文获取类型
收费全文 | 3171篇 |
免费 | 195篇 |
国内免费 | 93篇 |
专业分类
电工技术 | 210篇 |
综合类 | 111篇 |
化学工业 | 188篇 |
金属工艺 | 107篇 |
机械仪表 | 110篇 |
建筑科学 | 158篇 |
矿业工程 | 37篇 |
能源动力 | 45篇 |
轻工业 | 265篇 |
水利工程 | 58篇 |
石油天然气 | 44篇 |
武器工业 | 53篇 |
无线电 | 181篇 |
一般工业技术 | 159篇 |
冶金工业 | 1441篇 |
原子能技术 | 35篇 |
自动化技术 | 257篇 |
出版年
2024年 | 7篇 |
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 61篇 |
2020年 | 50篇 |
2019年 | 34篇 |
2018年 | 37篇 |
2017年 | 42篇 |
2016年 | 53篇 |
2015年 | 64篇 |
2014年 | 92篇 |
2013年 | 107篇 |
2012年 | 137篇 |
2011年 | 158篇 |
2010年 | 139篇 |
2009年 | 114篇 |
2008年 | 125篇 |
2007年 | 145篇 |
2006年 | 147篇 |
2005年 | 87篇 |
2004年 | 87篇 |
2003年 | 48篇 |
2002年 | 56篇 |
2001年 | 67篇 |
2000年 | 40篇 |
1999年 | 52篇 |
1998年 | 417篇 |
1997年 | 245篇 |
1996年 | 162篇 |
1995年 | 78篇 |
1994年 | 74篇 |
1993年 | 109篇 |
1992年 | 23篇 |
1991年 | 26篇 |
1990年 | 16篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 25篇 |
1986年 | 12篇 |
1985年 | 20篇 |
1984年 | 5篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 21篇 |
1978年 | 4篇 |
1977年 | 35篇 |
1976年 | 101篇 |
1975年 | 7篇 |
1964年 | 3篇 |
1955年 | 4篇 |
排序方式: 共有3459条查询结果,搜索用时 31 毫秒
1.
IH Bjerkli R Myklebust S R?is?nen S Telimaa LE Stenfors 《Canadian Metallurgical Quarterly》1996,36(3):205-213
Dopaminergic agents and carbidopa/levodopa have become the preferred treatment for both the restless legs (RL) syndrome and for periodic limb movements in sleep (PLMS). For once-nightly treatments with carbidopa/ levodopa, a problem with morning end-of-dose rebound increases in leg movements has been reported to occur in the about one-fourth of the patients. In our clinical studies a previously unreported but far more significant problem of markedly augmented RL symptoms occurred in the afternoon and the evening prior to taking the next nightly dose. A systematic prospective evaluation of this augmentation in 46 consecutive patients treated with carbidopa/ levodopa for RL syndrome or PLMS disorder found this augmentation to be the major adverse effect of treatment. Augmentation occurred for 31% of PLMS patients and 82% of all RL patients. It was greater for subjects with more severe RL symptoms and for patients on higher doses (> or = 50/200 mg carbidopa/levodopa) but was unrelated to gender, age or baseline severity of PLMS. This augmentation was severe enough to require medication change for 50% of the RL patients and 13% of PLMS patients. Augmentation resolved with cessation of the medication and could be minimized by keeping the dose low. 相似文献
2.
Recurrent erosion of the corneal epithelium has been treated successfully by phototherapeutic keratectomy when convention therapy has failed. We present a case of recurrent corneal erosion occurring 1 year after photorefractive keratectomy in a 55-year-old myopic woman. No corneal abnormalities were previously identified in either the affected or the fellow eye. This case demonstrates the potential for ineffective healing of the corneal epithelial basement membrane complex after excimer laser photorefractive keratectomy. 相似文献
3.
LE Lindner 《Canadian Metallurgical Quarterly》1993,41(3):439-445
The silver-staining technique for nucleolar organizer regions (AgNOR) of Ploton et al., as popularized by Crocker, is being widely used for evaluation of nucleolar function, especially in neoplasia. It suffers from limited reliability, background staining, precipitates, and fading of the sections. Factors were identified that affect these problems. The oxidation-reduction level and gelatin used are particularly important. An improved procedure is presented which incorporates pre-reduction of the sections, selection of an optimal gelatin, and post-treatment of the sections to produce a permanent preparation. It is compatible with many fixatives and with other stains used before or after the silver stain. 相似文献
4.
D Averill D Blockus B Brabson J Brom C Jung H Ogren DR Rust M Derrick P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano B Cork C Akerlof J Chapman D Errede MT Ken DI Meyer H Neal D Nitz R Thun R Tschirhart S Abachi P Baringer BG Bylsma R DeBonte D Koltick EH Low RL McIlwain DH Miller CR Ng EI Shibata 《Canadian Metallurgical Quarterly》1989,39(1):123-137
5.
6.
Shape representation by multiscale contour approximation 总被引:3,自引:0,他引:3
7.
The technique of immunocytochemistry was used to identify myoglobin in kidney, confirming a diagnosis of neuroleptic malignant syndrome following an otherwise obscure autopsy in a decomposed body. The features of neuroleptic malignant syndrome are reviewed with a differential diagnosis of myoglobin renal casts. The report emphasizes a thorough and detailed assessment of deaths which occur during treatment with neuroleptic drugs. 相似文献
8.
We developed a new in vitro model of neuronal injury using NT2-N cells to examine the effects of hydrodynamic loading rate on intraneuronal calcium dynamics and lactate dehydrogenase (LDH) release. Our apparatus consisted of a parallel disk viscometer which induced fluid shear stress with well-defined magnitudes and loading rates to cultured cells. We found that the deformation response of the cells was dependent on the severity of the insult, with increased cellular strains generated for higher shear stresses at a constant loading rate. Peak intracellular free calcium concentration correlated with strain, suggesting that mechanical deformation may regulate calcium response. Slowly applied fluid shear stress elicited no response, whereas high loading rates resulted in peak calcium increases 2.9 to 3.6 times baseline values as injury severity was increased. LDH release measured within 5 min after the insult correlated with loading rate. In addition, LDH release continued to increase out to 24 h following high loading rate conditions, demonstrating that the application of fluid shear stress led to prolonged cell damage. The acute response in NT2-N cells subjected to an insult with the CSID is dependent on the loading rate, and these results suggest that initial membrane deformation may trigger subsequent events. 相似文献
9.
A Bengtsson L Holm O B?ck J Fransson A Scheynius 《Canadian Metallurgical Quarterly》1997,109(3):533-537
The immunopathology of AD is still unclear, but evidence for an immune response polarized towards Th2 activity has been provided. The CD30 molecule belongs to the tumour necrosis factor (TNF) receptor family and is expressed on activated T cells with a sustained expression in Th2 cells. This molecule also exists in a soluble form (sCD30). Elevated serum levels of sCD30 have been found in patients with Hodgkin's disease, chronic hepatitis B infection and HIV infection. Studies were undertaken to compare the serum levels of sCD30 in patients with AD (n=49) and healthy non-atopic controls (n=94). The presence of sCD30 was analysed with ELISA. A significantly higher concentration of sCD30 was noted in AD patients, median sCD30 level 29 U/ml (range 1-708 U/ml), compared with healthy non-atopic controls (P<0.001), where the median level was 11 U/ml with a range of 1-1042 U/ml. No correlation was found between sCD30 levels and total serum IgE, or between the AD patients' SCORAD values and concentration of sCD30. sCD30 levels were also analysed in 20 AD patients, which during ketoconazole treatment had improved their clinical scores and reduced their serum IgE and eosinophil cationic protein levels. However, no significant decrease in sCD30 levels was noted after treatment. The results show that patients with AD have elevated levels of sCD30, but without correlation to total serum IgE or disease activity. 相似文献
10.
TF Tihanyi K Morvay L Nehéz T Winternitz Z Rusz LE Flautner 《Canadian Metallurgical Quarterly》1997,36(1-4):359-361
Management of the pancreatic diseases is still a challenge to the laparoscopic technique. Some experience has been gained in the laparoscopic exploration of the pancreas and staging in cancer. Anatomically the accessibility of the distal pancreas provides the laparoscopic approach technically feasible. Patient and method: A case of insuloma in the tail of the pancreas is presented, where distal pancreatic resection was performed laparoscopically with the preservation of the spleen. In a 55 years old female patient with typical clinical symptoms of hyperinsulinism CT identified a 3 cm large solid tumor in the tail of the pancreas. Complete mobilization of the distal pancreas was enhanced by the use of an ultrasonic dissector (UltraCision). The pancreas is detached from the splenic hilum after dividing the spleen vessels. The pancreas is transected proximally by laparoscopic linear stapler. Preservation of the short gastric vessels provides the necessary blood supply of the spleen following division of the splenic artery and vein. Thus removal of the spleen is not a necessary step in this procedure. The operation was carried out within 4.5 hours. Postoperative course was uneventful, the patient left the hospital on the 5th postoperative day. Advantages of the procedure were the earlier mobilization and shorter recovery time, less postoperative pain. The procedure can be safely performed with a good experience in both pancreatic and laparoscopic surgery. 相似文献