全文获取类型
收费全文 | 1272篇 |
免费 | 75篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 14篇 |
综合类 | 5篇 |
化学工业 | 310篇 |
金属工艺 | 23篇 |
机械仪表 | 13篇 |
建筑科学 | 56篇 |
矿业工程 | 3篇 |
能源动力 | 23篇 |
轻工业 | 212篇 |
水利工程 | 6篇 |
石油天然气 | 5篇 |
无线电 | 57篇 |
一般工业技术 | 185篇 |
冶金工业 | 327篇 |
原子能技术 | 14篇 |
自动化技术 | 97篇 |
出版年
2023年 | 9篇 |
2022年 | 42篇 |
2021年 | 62篇 |
2020年 | 21篇 |
2019年 | 27篇 |
2018年 | 38篇 |
2017年 | 31篇 |
2016年 | 40篇 |
2015年 | 36篇 |
2014年 | 51篇 |
2013年 | 53篇 |
2012年 | 67篇 |
2011年 | 78篇 |
2010年 | 41篇 |
2009年 | 49篇 |
2008年 | 58篇 |
2007年 | 46篇 |
2006年 | 42篇 |
2005年 | 44篇 |
2004年 | 28篇 |
2003年 | 25篇 |
2002年 | 27篇 |
2001年 | 9篇 |
2000年 | 15篇 |
1999年 | 17篇 |
1998年 | 67篇 |
1997年 | 40篇 |
1996年 | 48篇 |
1995年 | 23篇 |
1994年 | 18篇 |
1993年 | 27篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1985年 | 9篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1976年 | 18篇 |
1975年 | 5篇 |
1973年 | 5篇 |
1968年 | 3篇 |
1957年 | 3篇 |
排序方式: 共有1350条查询结果,搜索用时 11 毫秒
91.
Guido Velten Anja S. Rott Csar Cardona Silvia Dorn 《Journal of Stored Products Research》2007,43(4):550-557
To protect stored beans from attack by Acanthoscelides obtectus and other bruchids by non-toxic means of control, it is desirable to combine mutually compatible methods in an integrated approach. A combination of an optimal level of host–plant resistance based on the natural storage protein arcelin and a larval parasitoid has been suggested as a promising two-component strategy. While a dose–response to arcelin is evident in the bruchid Zabrotes subfasciatus, the effects of different arcelin concentrations on A. obtectus are still virtually unknown, even though they might be important for the success of the proposed integrated control system. The current investigation quantified the effect of different arcelin-based resistance levels of beans on the development of A. obtectus in a series of bioassays. Our findings show that all seven tested bean lines with markedly different levels of arcelin-based resistance against Z. subfasciatus consistently prolonged development of A. obtectus. Results provide clear evidence that arcelin acts as a growth inhibitor on first instar larvae. Furthermore, arcelin affected bruchid female fitness through its effect on body mass, which was significantly reduced on all arcelin-containing bean lines. This study demonstrates that, irrespective of its relative concentration, arcelin holds the potential to affect development of A. obtectus sufficiently to support the proposed two-component integrated pest management system. 相似文献
92.
93.
Mirco Wegener Matthias Kraume Anja R. Paschedag 《American Institute of Chemical Engineers》2010,56(1):2-10
The knowledge of the drop rise velocity in dispersed systems is of fundamental importance. Especially, the residence time is needed for calculation of mass transfer rates in extraction columns. This work deals with fluid dynamic measurements of toluene droplets rising in water ranging from 1.0 to 7.0 mm, with the premise of high purity of the used chemicals. The toluene/water‐system is widely used as a test system with high interfacial tension. A semiempirical correlation for pure systems to predict the terminal velocity of single rising/falling droplets based on experimental data is presented. Results show that a distinction between maximum and characteristic mean values of the drop rise velocity is necessary, especially in the diameter range 2.4–3.0 mm where unexpected velocity fluctuations occur. Two distinct terminal rise velocities were observed for 3 mm droplets. Furthermore, comparisons of the Weber‐Reynolds‐correlation and the drag coefficient with correlations from literature show good agreement. © 2009 American Institute of Chemical Engineers AIChE J, 2009 相似文献
94.
Hartmut Schwertfeger MareikeM. Machuy Christian Würtele Jeremy E.P. Dahl Robert M.K. Carlson PeterR. Schreiner 《Advanced Synthesis \u0026amp; Catalysis》2010,352(4):609-615
The diamondoids (nanodiamonds) diamantane and triamantane were selectively converted into diorganophosphinic acid chlorides by reacting them with phosphorus trichloride under Friedel–Crafts‐like conditions. The di‐diamondoid phosphinic acid chlorides were subsequently reduced with trichlorosilane to give the hitherto unknown corresponding di‐diamondoid phosphines. These diamondoid phosphinic acid chlorides and phosphines are of great utility as starting materials in organo‐element and coordination chemistry due to their extraordinary rigidity and steric bulk. 相似文献
95.
Lienemann T Niskanen T Guedes S Siitonen A Kuusi M Rimhanen-Finne R 《Journal of food protection》2011,74(6):1035-1040
A nationwide outbreak of Salmonella enterica serotypes Newport and Reading occurred between 17 October and 28 November 2008 in Finland. A total of 77 culture-confirmed Salmonella Newport and 30 Salmonella Reading cases, including one case with a double infection, were reported. All strains isolated from the patients were subtyped using serotyping, microbial resistance profiling, and pulsed-field gel electrophoresis (PFGE). Here, the PFGE patterns of the studied Salmonella Newport strains were identical, whereas four different PFGE profiles were found among the Salmonella Reading strains. Two elderly patients died within 2 weeks of the onset of symptoms. Three geographical clusters of cases with an epidemiological link were identified. The traceback investigation suggested that the factor connecting the cases was ready-chopped iceberg lettuce available for mass catering use. However, none of the tested food, environmental samples, or the samples taken from the staff of the processing plant contained Salmonella bacteria. Tracing back to outbreak sources with a short shelf life can be complex. 相似文献
96.
The connection between the mode of toxic action and the genetic response caused by the type I photosensitizer and photosynthesis inhibitor neutral red (NR) and the type II photosensitizer rose bengal (RB) was investigated in the green alga Chlamydomonas reinhardtii. For both photosensitizers, a light intensity-dependent increase in toxicity and expression of the glutathione peroxidase homologous gene (Gpxh) was found. The toxicity of RB was reduced by the singlet oxygen (1O2) quenchers 1,4-diazabicyclo[2.2.2]octane and L-histidine, and the RB-induced Gpxh expression was stimulated in deuterium oxide-supplemented growth medium. These observations clearly indicate the involvement of 1O2 in both toxicity and the genetic response caused by RB. NR up-regulated the expression of typical oxidative and general stress response genes, probably by a type I mechanism, and also strongly induced the Gpxh expression. The stimulating effect of deuterium oxide in the growth medium suggested the involvement of 1O2 also in the NR-induced response. Indeed, an increased 1O2 formation was detected with EPR-spin trapping in NR-treated spinach thylakoids. However, none of the 102 quenchers could reduce the light-dependent toxicity of NR in C. reinhardtii, indicating that NR has a different mode of toxic action than RB. 相似文献
97.
Effects of tumbling and RN genotype on sensory perception of cured-smoked loins were studied on loins from 32 crossbred female pigs containing Hampshire blood. Right-side loins were intermittently tumbled during 4 h, whereas left-side loins were left non-tumbled. Tumbled loins were more tender and uniform in cured colour as well as less acidulous in taste compared with non-tumbled loins. Further, the formation of undesirable pores was lower in tumbled loins. Final juiciness tended to be higher and meat taste intensity lower in tumbled loins, whereas initial juiciness did not differ. There were no significant interactions between tumbling and RN genotype for sensory attributes. RN− carriers (RN−/rn+) were more acidulous in taste, had more pronounced meat taste and were saltier than non-carriers (rn+ /rn+). Moreover, they tended to have higher initial juiciness and more undesirable pores, and be less homogeneous in cured pink colour. No differences in consumer preference between the four treatments were detected in the ranking test, but most persons ranked non-tumbled loins highest regarding overall liking. Instrumental tenderness measurements agreed well with sensory tenderness scores. 相似文献
98.
Dirkzwager Anja J. E.; Bramsen Inge; Adèr Herman; van der Ploeg Henk M. 《Canadian Metallurgical Quarterly》2005,19(2):217
This study examines secondary traumatization among 708 partners and 332 parents of Dutch peacekeepers (i.e., personnel who participated in military actions implemented by international organizations such as the United Nations). Partners or parents of peacekeepers with 4 levels of posttraumatic stress symptoms were compared on posttraumatic stress, health problems, the quality of the marital relationship, and social support. In comparison with partners of peacekeepers without posttraumatic stress disorder (PTSD) symptoms, partners of peacekeepers with PTSD symptoms reported more sleeping and somatic problems, reported more negative social support, and judged the marital relationship as less favorable. No significant differences were found for parents. Thus, peacekeepers' stress reactions were related to various problems of their partners. A systemic approach to the treatment of persons with PTSD appears appropriate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
Zoltan Nagy Bratislav Svetozarevic Prageeth Jayathissa Moritz Begle Johannes Hofer Gearoid Lydon Anja Willmann Arno Schlueter 《建筑学研究前沿(英文版)》2016,5(2):143
The Adaptive Solar Facade (ASF) is a modular, highly integrated dynamic building facade.The energetic behavior as well as the architectural expression of the facade can be controlled with high spatio-temporal resolution through individually addressable modules. We present the general design process, the current mechanical design, and simulation results on photovoltaic power production and building energy consumption. We introduce the controller concept and show results on solar tracking as well as user interaction. Lastly, we present our current and planned prototypes. 相似文献
100.
This paper presents recent experimental investigations on the influence of loading rate on the fracture toughness KIc for different structural steels. The loading rate in terms of increasing in stress intensity factor was changed from quasistatic up to dynamic conditions (
). The results show significant differences in the amount of temperature shift between KIc -T curve obtained after static and dynamic loading for the materials investigated. Based on microscopic fracture criteria for cleavage fracture correlations were made between fracture toughness and yielding behaviour depending on temperature and strain rate. The experimental results were also compared with the predictions given by different models. The most promising results were achieved by a correlation between transition temperature shift in KIc caused by dynamic loading and strain rate sensitivity
of steels. 相似文献
Full-size image (<1K)