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31.
Mechanical properties and low cycle fatigue are two factors that must be considered in developing new type steel for shock
absorption. Process capability and process control are significant factors in achieving the purpose of research and development
programs. Often-used evaluation methods failed to measure process yield and process centering; so this paper uses Taguchi
loss function as basis to establish an evaluation method and the steps for assessing the quality of mechanical properties
and process control of an iron and steel manufacturer. The establishment of this method can serve the research and development
and manufacturing industry and lay a foundation in enhancing its process control ability to select better manufacturing processes
that are more reliable than decision making by using the other commonly used methods. 相似文献
32.
33.
利用x-线衍射、扫描电镜和透射电镜等手段对三种不同来源的SiC晶须的热稳定性进行了研究。实验发现SiC晶须在180℃以上显微结构发生变化,长径比减小。讨论变化机质及对复合陶瓷性能的影响。 相似文献
34.
石铸 《中国科学院研究生院学报》1979,17(4):61-71
The present paper is an attempt to propose a preliminary taxomomic treatment of
the genus Hippolytia Poljak. and to analyse the geographical distribution of its com-
posite elements.
This small genus with 17 species is divided into 2 sections, namely, section
Anthodesma Shih and section Hippolytia. Anthodesma is a small section with 3 species
and is characterized by fascicled corymbs, campanulate and nitid involucres, rigidly
herbaceous phyllaries, and undershrubs, while Hippolytia consisting of 14 species is
characterized by corymbose inflorescence or glomerules or compund heads, cuneate and
unpolished involucres, herbaceous phyllaries with pitch black margines.
There are 12 species of Hippolytia in China, of which 3 are proposed as new in the
present paper.
Regarding the distribution pattern of Hippolytia, it is noteworthy to note that its
range of distribution forms a more or less U-shape as shown in map 2. It may be seen
that Hippolytia distributes in Central Asia-Sino-Himalaya-Median Asia. Section Antho-
desma Shih occurs in central Asia, while section Hippolytia in the whole Himalayan
region and northern Meridional Ranges and Median Asia.
There seems to be no center of species concentration within the total range of
Hippolytia, whose species are localized in distribution, for example, H. desmantha Shih
is known only from Qinghai provence (Yu-Shu-Hsien), H. alashanensis (Ling) Shih
is restricted to Ninghsia and central part of Kansu provence. It is interesting to note
that H. yunnanensis (J. F. Jeffrey) Shih and H. longifolia (Wall.) Shih are referred
to as vicarious species. The localization of the species distribution and the obvious
discontinuity of morphological characters between species indicate a remarkable geogra-
phical influence on the species formation of Hippolytia.
Hippolytia is an alpine genus of temperate zone of Asia, in which 64 per cent of
species occurs at high elevations of above 3300m. altitude, 30 per cent of species are
distributed in middle elevations of above 2200m. altitude. The life forms are micro-
undershrubs, erect perennial herbs, glomerule stemless herbs or stemless herbs. It is very
possible that its geographical origin and development may be linked up with occurance
of desert steppe, especially of alpine meadow vegetations in the northern temperate
zone of Asia.
With regard to the geographical elements to which each species of Hippolytia
belongs, it seems to indicate that H. trifida (Turcz.) Poljak., H. alashanensis (Ling)
Shih and H. desmantha Shih belong to the geographical elements of central Asia,
while H. yunnanensis (J. F. Jeffrey) Shih, H. glomerata Shih, H. tomentosa (DC.)
Tzvel., H. senecionis (Bess.) Poljak. H. longifolia (Wall.) Shih, H. kennedayi (Dunn)
Ling, H. syncalathiformis Shih, H. gossypina (Hook. f. et Thoms.) Shih and H. nana
(C. B. Clarke) Shih to Himalayan elements, and H. darvasica (C. Winkl.) Poljak., H.
megacephala (Rupr.) Poljak,, H. herderi (Rgl. et Schmalh.) Poljak. to Median Asia, H.
delavayi (W. W. Smith) Shih to North-West-Yunna.
相似文献
35.
Termite colonies from mid-Cretaceous Myanmar demonstrate their early eusocial lifestyle in damp wood
Insect eusociality is characterized by cooperative brood care, reproductive division of labour and multiple generations of adults within a colony. The morphological specializations of the different termite castes from Burmese amber were recently reported, indicating the termites possessed advanced sociality in the mid-Cretaceous. Unfortunately, all the reported Cretaceous termites are individually preserved, which does not cover the behaviours of the cooperative brood care and multiple generations of adults in the nests of the Cretaceous termites. Herein, we report three eusocial aggregations from colonies of the oldest known Stolotermitidae, Cosmotermesgen. nov., in 100 Ma mid-Cretaceous Burmese amber. One large aggregation, comprising 8 soldiers, 56 workers/pseudergates and 25 immatures of different instars, additionally presents the behaviours of cooperative brood care and overlapping generations. Furthermore, taphonomic evidence indicates Cosmotermes most probably dwelled in damp/rotting wood, which provides a broader horizon of the early societies and ecology of the eusocial Cosmotermes. 相似文献
36.
Shih‐Ching Yeh Jin‐Liang Wang Chin‐Yeh Wang Po‐Han Lin Gwo‐Dong Chen Albert Rizzo 《British journal of educational technology : journal of the Council for Educational Technology》2014,45(4):666-675
Mental rotation is an important spatial processing ability and an important element in intelligence tests. However, the majority of past attempts at training mental rotation have used paper‐and‐pencil tests or digital images. This study proposes an innovative mental rotation training approach using magnetic motion controllers to allow learners to manipulate and interact with three‐dimensional (3D) objects. Stereovision allows learners to perceive the spatial geometric form of a 3D object. This approach allows learners to perceive 3D objects in space through stereovision and make mental rotation visible from each intrinsic and invisible mental rotation step using motion‐interaction methods. This study examines the effects of user training performance and perceptions. The results indicate that the proposed approach can improve user mental rotation ability effectively. Learners expressed high degrees of concentration toward the mechanism that included direct control and immediate feedback. The results also suggest that female testers perceive greater degrees of playfulness toward the mechanism and improve more through training than male testers. 相似文献
37.
Energy dissipators, isolated-resistant and specific structural forms for earthquake resistance are popular topics in the research
to improve shock-resistance. In this work, experimental methods were used to investigate the property of low yield strength
steel. Carbon content in LYS material is lower than that in other steels; the ultimate stress is three times the yield stress.
The ultimate elongation rate is about 62% and the ductility is 2–3 times that of A36 steel. In order to overcome some defects
of ordinary use metallic dampers, the mechanical characteristic of low yield strength steel is used to develop added damping
and stiffness for rhombic steel plate absorber. Test of the energy dissipation behavior for this newly developed device indicated
that LYS could stably dissipate or absorb the input energy of earthquake. Then, the analytical model for the hysteretic behavior
of this new device is proposed. Comparison of experimental data and numerical simulation results showed that this analytical
model is suitable for simulating the hysteretic energy behavior of this new device. 相似文献
38.
Minyi Shih Dennis 《Learning disabilities research & practice》2015,30(1):29-42
Two studies were conducted to examine the effects of Tier 2 and Tier 3 mathematics interventions on students with mathematics learning difficulties. In the first study, the work of Bryant et al. was replicated and expanded upon by documenting the sustained effects of a Tier 2 mathematics intervention on mathematics performance by second graders. In the second study, the Tier 2 intervention was intensified to a Tier 3 intervention through increases in two instructional features: group size and dosage. The results of the first study showed that the Tier 2 intervention improved mathematics performance for the majority of student participated in the study, and the effect of the intervention was sustained for the majority of students who responded to the Tier 2 intervention. The results of the second study showed that intensified Tier 3 intervention that involved one‐on‐one instruction and extended time for daily lessons may benefit students who have persistent difficulties with learning mathematics. 相似文献
39.
石铸 《中国科学院研究生院学报》1986,24(4):292-296
Almost no differences are seen in habit and infrescence between the gene-
ra Vladimiria and Dolomiaea; the former that was founded on the basis of Jurinea sal-
winensis Hand.-Mazz. by Iljin should be transferred to the later that was earlier found-
ed on the basis of D. macrocephala DC. by De Candolle. But considering the style which
has fine, spreading and apex-acute branches in the group Vladimiria, it is reasonable
to treat the group Vladimiria as a section in the genus Dolomiaea, i.e. Dolomiaea sect.
Vladimiria (Iljin) Shih. Therefore, the genus Dolomiaea is expanded in the circums-
cription in the present paper, not only including the primary group with short, com-
pact and apex-rounded style branches, i.e. Dolomiaea sect. Dolomiaea, but also sect. Vla-
dimiria (Iljin) shih with different characters of style-arms.
Nine species and 1 variety as new combinations are listed in the sect. Vladimiria
(Iljin) Shih as following: D. denticulata (Ling) Shih, D. forrestii (Diels) Shih, D.
scabrida (Shih et S. Y. Jin) Shih, D. souliei(Franch.) Shih, D. souliei (Franch) Shih
var. mirabilis (Anth.) Shih, D. berardioidea (Franch.) Shih, D. georgii (Anth.) Shih,
D. edulis (Franch.) Shih, D. salwinensis (Hand.-Mazz.) Shih and D. platylepis (Hand.
-Mazz.) Shih. 相似文献
40.
SHIHTimothyK. CHANGRong-chi 《浙江大学学报(A卷英文版)》2005,6(6):487-491
INTRODUCTION Video sequences can be interfered with by noise.When the noise ratio of a video is high,even though itis not possible to restore the original,to repair videoframes or damaged artifacts with visually good resultis a hopefully achievable goal(see example in Fig.3),especially for archival resources in digital museumprojects.One of the simplest but efficient mecha-nisms is presented in(Oliveira et al.,2001).The dif-fusion kernel can repair damages of small area with abarrier to … 相似文献