全文获取类型
收费全文 | 2277篇 |
免费 | 19篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 98篇 |
金属工艺 | 17篇 |
机械仪表 | 36篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 32篇 |
轻工业 | 24篇 |
水利工程 | 8篇 |
石油天然气 | 4篇 |
无线电 | 47篇 |
一般工业技术 | 90篇 |
冶金工业 | 1797篇 |
原子能技术 | 3篇 |
自动化技术 | 111篇 |
出版年
2023年 | 10篇 |
2022年 | 17篇 |
2021年 | 27篇 |
2020年 | 24篇 |
2019年 | 24篇 |
2018年 | 29篇 |
2017年 | 16篇 |
2016年 | 40篇 |
2015年 | 20篇 |
2014年 | 18篇 |
2013年 | 39篇 |
2012年 | 43篇 |
2011年 | 43篇 |
2010年 | 28篇 |
2009年 | 27篇 |
2008年 | 20篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 75篇 |
1998年 | 602篇 |
1997年 | 301篇 |
1996年 | 204篇 |
1995年 | 126篇 |
1994年 | 110篇 |
1993年 | 104篇 |
1992年 | 6篇 |
1991年 | 17篇 |
1990年 | 26篇 |
1989年 | 12篇 |
1988年 | 20篇 |
1987年 | 8篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1983年 | 2篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 42篇 |
1976年 | 83篇 |
1975年 | 3篇 |
1971年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有2298条查询结果,搜索用时 31 毫秒
71.
Thanh Bao Nguyen Erwin van der Krabben Clément Musil Duc Anh Le 《International Planning Studies》2018,23(3):310-326
This paper explores how land-based financing mechanisms are currently used in Ho Chi Minh City as a public-private funding strategy. The Land-for-Infrastructure (LFI) mechanism appears as a solution to produce infrastructures. We found that the implementation of the LFI mechanism remains difficult, but eventually can lead to success. By ‘trial-error-transcend,’ the City managed to build two essential roads while the developers received attractive investment opportunities in urban development. This mechanism cannot, however, be seen as a panacea for the local authorities due to constraints to replicate it and potential undesired ‘side effects.’ 相似文献
72.
Nguyen Tuan Anh Han Kihong Min Dugki Choi Eunmi Thang Tran Duc Choi Yun-Jeong 《The Journal of supercomputing》2019,75(8):4657-4683
The Journal of Supercomputing - The networking infrastructure of a software-defined network (SDN) requires further study to achieve continuity and high availability of data transactions for cloud... 相似文献
73.
The magnetoelectric sensor based on (Fe80Co20)78Si12B10/PZT laminates is designed, fabricated and characterized for determining dc and ac magnetic-field strengths as well as field orientations. At low dc magnetic-fields, a ME-voltage response (dVME/dH) as high as 2 mV/Oe is achieved. The linear relation VME(hac) with a slope of dVME/dhac of 17 mV/Oe shows a great ability to self-powered detecting low ac magnetic-fields. The field orientation can be detected by using the sinusoidal dependence of the magnetoelectric voltage. The sensor is promising not only for microtesla magnetic-field sensing but also for magnetic biosensor applications. 相似文献
74.
CK Combs DE Johnson SB Cannady TM Lehman GE Landreth 《Canadian Metallurgical Quarterly》1999,19(3):928-939
Microglial interaction with amyloid fibrils in the brains of Alzheimer's and prion disease patients results in the inflammatory activation of these cells. We observed that primary microglial cultures and the THP-1 monocytic cell line are stimulated by fibrillar beta-amyloid and prion peptides to activate identical tyrosine kinase-dependent inflammatory signal transduction cascades. The tyrosine kinases Lyn and Syk are activated by the fibrillar peptides and initiate a signaling cascade resulting in a transient release of intracellular calcium that results in the activation of classical PKC and the recently described calcium-sensitive tyrosine kinase PYK2. Activation of the MAP kinases ERK1 and ERK2 follows as a subsequent downstream signaling event. We demonstrate that PYK2 is positioned downstream of Lyn, Syk, and PKC. PKC is a necessary intermediate required for ERK activation. Importantly, the signaling response elicited by beta-amyloid and prion fibrils leads to the production of neurotoxic products. We have demonstrated in a tissue culture model that conditioned media from beta-amyloid- and prion-stimulated microglia or from THP-1 monocytes are neurotoxic to mouse cortical neurons. This toxicity can be ameliorated by treating THP-1 cells with specific enzyme inhibitors that target various components of the signal transduction pathway linked to the inflammatory responses. 相似文献
75.
L Dupclay MT Rupp RW Bennett TM Jarnagin 《Canadian Metallurgical Quarterly》1999,39(1):74-81; quiz 105-6
OBJECTIVE: To measure grocery chain pharmacists' work-related behaviors to assess the impact of a Pharmaceutical Care Certificate Program (PCCP) and other future interventions intended to alter pharmacists' practice behaviors. DESIGN: This study used multidimensional work sampling (MWS), a work measurement methodology that breaks "work" into three components: activity (what was done), contact (with whom the activity was performed), and function (the purpose or objective of the activity). Pharmacists were signaled at random intervals during the workday by a random signal generator. A selection was made from a list of items in each of the three dimensions of work to form an activity-contact-function combination code that described the work-related behavior at that point in time. SETTING AND PARTICIPANTS: Pharmacists in 15 grocery chain stores in the Indianapolis area; 20 pharmacists were enrolled in Purdue University's PCCP and 10 served as controls. Data were collected for a period of six weeks during April through June 1997 before the beginning of the PCCP program. MAIN OUTCOME MEASURES: Pharmacists' work-related behaviors. RESULTS: Writing/keyboarding was the most frequently recorded activity (22%), followed by one-to-one meetings (21.6%), and drug preparation (18%). Pharmacists spent most of their time working alone (62.9%), while a smaller but still substantial proportion of time was spent interacting with patients (17.9%). The most frequently recorded purpose (i.e., function) of pharmacists' activities was drug distribution (23.9%), followed by personal time (12.4%), receiving or transferring a medication order (10.2%), and patient counseling (6.6%). Out of a possible, 1,760 activity-contact-function combinations, 10 accounted for 46.3% of all reported observations, with "Prepare drug-Self-Drug distribution" representing the most frequently recorded activity-contact-function combination (15.7%). CONCLUSION: MWS is useful in helping grocery chain management better understand how pharmacy personnel are currently being utilized. This study provides a baseline for evaluating the impact of training programs or other alterations in the practice environment on pharmacists' work-related behaviors. 相似文献
76.
TM Field 《Canadian Metallurgical Quarterly》1998,53(12):1270-1281
Massage therapy is older than recorded time, and rubbing was the primary form of medicine until the pharmaceutical revolution of the 1940s. Popularized again as part of the alternative medicine movement, massage therapy has recently received empirical support for facilitating growth, reducing pain, increasing alertness, diminishing depression, and enhancing immune function. In this article studies are reviewed that document these effects, and models are proposed for potential underlying mechanisms. 相似文献
77.
78.
MJ Clemons E Marshall J Dürig K Watanabe A Howell D Miles H Earl J Kiernan A Griffiths K Towlson P DeTakats NG Testa M Dougal MG Hunter LM Wood LG Czaplewski A Millar TM Dexter BI Lord 《Canadian Metallurgical Quarterly》1998,92(5):1532-1540
BB-10010 is a variant of the human form of macrophage inflammatory protein-1alpha (MIP-1alpha), which has been shown in mice to block the entry of hematopoietic stem cells into S-phase and to increase their self-renewal capacity during recovery from cytotoxic damage. Its use may constitute a novel approach for protecting the quality of the stem cell population and its capacity to regenerate after periods of cytotoxic treatment. Thirty patients with locally advanced or metastatic breast cancer were entered into the first randomized, parallel group controlled phase II study. This was designed to evaluate the potential myeloprotective effects of a 7-day regimen of BB-10010 administered to patients receiving six cycles of 5-fluorouracil (5-FU), adriamycin, and cyclophosphamide (FAC) chemotherapy. Patients were randomized, 10 receiving 100 microgram/kg BB-10010, 11 receiving 30 microgram/kg BB-10010, and nine control patients receiving no BB-10010. BB-10010 was well-tolerated in all patients with no severe adverse events related to the drug. Episodes of febrile neutropenia complicated only 4% of the treatment cycles and there was no difference in incidence between the treated and nontreated groups. Studies to assess the generation of progenitor cells in long-term bone marrow cultures were performed immediately preceding chemotherapy and at the end of six dosing cycles in 18 patients. Circulating neutrophils, platelets, CD 34(+) cells, and granulocyte/macrophage colony-forming cell (GM-CFC) levels were determined at serial time points in cycles 1, 3, and 6. The results showed similar hemoglobin and platelet kinetics in all three groups. On completion of the six treatment cycles, the average pretreatment neutrophil levels were reduced from 5.3 to 1.7 x 10(9)/L in the control patients and from 4.3 to 1.9 and 4.5 to 2.5 x 10(9)/L in the 30/100 microgram/kg BB-10010 groups, respectively. Relative to their pretreatment values, 50% of the patients receiving BB-10010 completed the treatment with neutrophil values significantly higher than any of the controls (P = .02). Mobilization of GM-CFC was enhanced by BB-10010 with an additional fivefold increase over that generated by chemotherapy alone, giving a maximal 25-fold increase over pretreatment values. Bone marrow progenitor assays before and after this standard regimen of chemotherapy indicated little long-term cumulative impairment to recovery from chemotherapy. Despite the limited cumulative damage to the bone marrow, which may have minimized the protective value of BB-10010 during this regimen of chemotherapy, better recovery of neutrophils in the later treatment cycles with BB-10010 was indicated in a number of patients. 相似文献
79.
80.
Effective Hamiltonian for the superconducting Cu oxides 总被引:1,自引:0,他引:1