全文获取类型
收费全文 | 626篇 |
免费 | 37篇 |
专业分类
电工技术 | 5篇 |
综合类 | 3篇 |
化学工业 | 184篇 |
金属工艺 | 6篇 |
机械仪表 | 17篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 123篇 |
水利工程 | 6篇 |
无线电 | 29篇 |
一般工业技术 | 92篇 |
冶金工业 | 80篇 |
原子能技术 | 3篇 |
自动化技术 | 80篇 |
出版年
2023年 | 13篇 |
2022年 | 15篇 |
2021年 | 25篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 30篇 |
2015年 | 12篇 |
2014年 | 31篇 |
2013年 | 22篇 |
2012年 | 35篇 |
2011年 | 48篇 |
2010年 | 28篇 |
2009年 | 26篇 |
2008年 | 32篇 |
2007年 | 22篇 |
2006年 | 26篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 26篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有663条查询结果,搜索用时 15 毫秒
141.
LD Berthold M Hoppe H K?nig B Saar HJ Wagner W Lorenz KJ Klose 《Canadian Metallurgical Quarterly》1998,169(6):585-589
Triple pelvic osteotomy reorients the acetabulum relative to the pelvis in order to improve acetabular coverage of the femoral head in cases of acetabular dysplasia. We undertook a radiostereometric analysis (RSA) on 6 osteotomized cadaver hips to determine the actual three-dimensional reorientation obtained. The centers of the femoral head were all translated posteriorly between 11 and 41 mm, and distally up to 13 mm. 4 were lateralized up to 8 mm, and 2 were medialized up to 5 mm. All acetabuli rotated anteriorly about the lateral to medial axis (X-axis), and 4 rotated outwards around the distal to proximal axis (Y-axis). The correlations between measurements performed on conventional anteroposterior radiographs and the RSA measurements were poor: variations in the lateral-medial direction ranged from -16 to +6 mm, and in the distal-proximal direction between -10 and +12 mm. The changes in orientations measured will significantly affect the load across the hip joint, since the dimensions of the pelvis change and the moment arms of the muscles, their lengths and lines of action are changed as well. We conclude that, with the procedures presently performed, the loads across the hip joint are bound to change, and that the reorientation can hardly be checked with conventional radiographs. 相似文献
142.
Bluhm H.J. Hoppe P.J.W. Laqua H.P. Rusch D. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1992,80(6):995-1009
A magnetically insulated proton diode in extraction geometry which has achieved an ion beam power of 0.8 TW and an ion production efficiency of greater than 90% is described. Using a Pd-Ti metal hydride film on the anode surface and diverting part of the generator current through it with the help of plasma opening switches, a proton-rich plasma is preformed on the anode before any voltage occurs across the diode gap. Thus it is possible to apply very strong magnetic insulation, V c/V op>3. Ion current and diode voltage simultaneously reach a plateau for 40 ns, resulting in a nearly constant diode impedance for 60 ns. Thus, chromatic aberrations of the diode focusing system are minimized. The microscopic divergence of proton beamlets due to diode effects is determined to be 0.7°. Geometric aberrations of spherical and aspherical anode shape have been determined. The experimental results are compared to simulations with a 2.5 dimensional stationary PIC (particle-incell) code 相似文献
143.
N Watanabe SC De Rosa A Cmelak R Hoppe LA Herzenberg M Roederer 《Canadian Metallurgical Quarterly》1997,90(9):3662-3672
We investigated the representation of T cells in patients who had been treated for Hodgkin's disease (HD). We found a marked depletion in both CD4 and CD8 naive T-cell counts that persists up to 30 years after completion of treatment. In contrast, CD4 and CD8 memory T-cell subsets recovered to normal or above normal levels by 5 years posttreatment. Thus, the previously-reported long-term deficit in total CD4 T-cell counts after treatment for HD is due to specific depletion of naive T cells. Similarly, total CD8 T-cell counts return to normal by 5 years only because CD8 memory T cells expand to higher than normal levels. These findings suggest that the treatment (mediastinal irradiation) results in a longterm dysregulation of T-cell subset homeostasis. The profound depletion of naive T cells may explain the altered T-cell function in treated patients, including the poor response to immunization after treatment for HD. Further, in some individuals, we identified expansions of unusual subsets expressing low levels of CD8. Eight-color fluorescence-activated cell sorting analyses showed that these cells largely express CD8alphaalpha homodimers and CD57, consistent with the phenotype of potentially extrathymically derived T cells. In addition, these cells, both CD4+ and CD4-, are probably cytotoxic lymphocytes, as they express high levels of intracellular perforin. In adults treated for HD, an increased activity of extrathymic T-cell differentiation may partially compensate for the loss of thymic-derived T cells. 相似文献
144.
Modellierung der anaeroben Bioabfallvergärung unter Berücksichtigung von syntrophen Propionat‐oxidierenden Bakterien
下载免费PDF全文
![点击此处可从《化学,工程师,技术》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anaerobic digestion of biowaste allows a sustainable production of bioenergy and reduces environmental burden. The anaerobic digestion phase was modeled with Anaerobic Digestion Model No. 1 (ADM1), which was extended to include three genera of propionate‐oxidizing bacteria and two routes of propionate degradation, namely methyl‐malonyl CoA and C6‐dismutation pathway. Kinetic parameters for anaerobic propionate oxidation were determined with defined tricultures of the three propionate‐oxidizing genera together with hydrogenotrophic and acetotrophic methanogens and implemented into ADM1, resulting in the improved model ADM1xpro. 相似文献
145.
Mayibongwe J. Lunga Ruramai L. Chisango Carli Weyers Michelle Isaacs Dr. Dale Taylor Prof. Adrienne L. Edkins Dr. Setshaba D. Khanye Prof. Heinrich C. Hoppe Dr. Clinton G. L. Veale 《ChemMedChem》2018,13(13):1353-1362
Despite major strides in reducing Plasmodium falciparum infections, this parasite still accounts for roughly half a million annual deaths. This problem is compounded by the decreased efficacy of artemisinin combination therapies. Therefore, the development and optimisation of novel antimalarial chemotypes is critical. In this study, we describe our strategic approach to optimise a class of previously reported antimalarials, resulting in the discovery of 1‐(5‐chloro‐1H‐indol‐3‐yl)‐2‐[(4‐cyanophenyl)thio]ethanone ( 13 ) and 1‐(5‐chloro‐1H‐indol‐3‐yl)‐2‐[(4‐nitrophenyl)thio]ethanone ( 14 ), whose activity was equipotent to that of chloroquine against the P. falciparum 3D7 strain. Furthermore, these compounds were found to be nontoxic to HeLa cells as well as being non‐haemolytic to uninfected red blood cells. Intriguingly, several of our most promising compounds were found to be less active against the isogenic NF54 strain, highlighting possible issues with long‐term dependability of malarial strains. Finally compound 14 displayed similar activity against both the NF54 and K1 strains, suggesting that it inhibits a pathway that is uncompromised by K1 resistance. 相似文献
146.
BACKGROUND AND DESIGN: There are no large studies evaluating patients with erythrodermic mycosis fungoides and Sézary syndrome to determine the important prognostic factors that may influence survival. This is important since new treatment modalities have been proposed as superior to existing primary therapies. We performed a retrospective cohort study of 106 patients with erythrodermic mycosis fungoides and Sézary syndrome, followed up in the Stanford (Calif) Mycosis Fungoides Clinic, to define the important prognostic factors in this group. RESULTS: Patients younger than 65 years have a more favorable survival profile than those 65 years or older (P < .005). Longer duration of symptoms before diagnosis ( > or = 10 years) tends to be associated with more favorable prognosis (p = .055). Lymph node stage is significantly correlated with survival; patients with overall stage III disease have more favorable prognosis than those with stage IV disease (P < .001). Patients with circulating Sézary cells in their blood have a significantly worse prognosis than those without (P < .005). Patient sex or race had no significant effect on overall survival outcome. Three distinct prognostic groups were identified, "favorable," "intermediate," and "unfavorable," according to the number of unfavorable prognostic factors (P < .005). The median survival in each group is 10.2, 3.7, and 1.5 years, respectively. CONCLUSIONS: In patients with erythrodermic mycosis fungoides and Sézary syndrome, the important prognostic factors are patient age at presentation, the overall stage, and peripheral blood involvement. Survival varies widely, depending on these variables. These prognostic factors should be evaluated when analyzing survival and/or treatment efficacy data of these patients. 相似文献
147.
André Calero Valdez Juliana Brell Anne Kathrin Schaar Martina Ziefle 《Universal Access in the Information Society》2018,17(3):549-566
In times of demographic change, skill shortage and disruptive innovations, organizational knowledge management and innovative capacity are the key to a company’s success. But how can knowledge be retained with fast staff turnover, global project-based work and parental leaves? Using enterprise social media to improve knowledge dissemination at work seems promising, when looking at the success of private social networking sites. In this article we combine ten different empirical studies which investigated different aspects of how user diversity influences the motivation to use social media at work. The emerging meta-study using the DerSimonian–Laird method (total sample size \(N=522\)) analyzes different aspects of user diversity and their correlation with eight motives for SNS usage: information, importance, contact, self-presentation, autonomy, social comparison, and power and control. We found that that the individual achievement motivation correlates positively with the motives importance, power, information and self-presentation. The need for autonomy correlates with openness to new experiences and the need for social comparison with gender and neuroticism. From our findings, we derive practical implications for designing a social networking site for work which fulfills the users’ needs and functions along their motivation. 相似文献
148.
DNA‐SMART: Biopatterned Polymer Film Microchannels for Selective Immobilization of Proteins and Cells
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ann‐Kathrin Schneider Pavel M. Nikolov Stefan Giselbrecht Christof M. Niemeyer 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(17)
A novel SMART module, dubbed “DNA‐SMART” (DNA substrate modification and replication by thermoforming) is reported, where polymer films are premodified with single‐stranded DNA capture strands, microthermoformed into 3D structures, and postmodified with complementary DNA‐protein conjugates to realize complex biologically active surfaces within microfluidic devices. As a proof of feasibility, it is demonstrated that microchannels presenting three different proteins on their inner curvilinear surface can be used for selective capture of cells under flow conditions. 相似文献
149.
150.
Miriam Knie Kathrin Schoppmann Hendrik Eck Bernard Wolfschoon Ribeiro Christian Laforsch 《Microgravity science and technology》2016,28(3):345-349
The Drop Tower Bremen, a ground-based facility enabling research under real microgravity conditions, is an excellent platform for testing new types of experimental hardware to ensure full performance when deployed in costly and rare flight opportunities such as suborbital flights. Here we describe the “Daphnia” experiment which will fly on XCOR Aerospace Lynx Mark I and our experience from the hardware tests with the catapult system at the drop tower. The aim of the “Daphnia” experiment is to obtain data on the biological performance of daphnids and predator-prey interactions in microgravity, which are important for the development of aquatic bioregenerative life support systems (BLSS). The experiment consists of two subunits: The first unit is dedicated to predator-prey interactions, where behavioural analysis should reveal if microgravity interfere with prey (Daphnia) detection or feeding and therefore may interrupt the trophic cascade. The functioning of such an artificial food web is indispensable for a long-lasting BLSS suitable for long-duration manned space missions or Earth-based explorations to extreme habitats. The second unit is designed to investigate the impact of microgravity on gene expression and the cytoskeleton in Daphnia. Next to data collection, the real microgravity conditions at the drop tower have helped to identify the weak points of the “Daphnia” experimental hardware and lead to further improvement. Hence, the drop tower is ideal for testing new experimental hardware which is indispensable before the implementation in suborbital flights. 相似文献