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排序方式: 共有536条查询结果,搜索用时 93 毫秒
111.
Keiichi Matsubara Yuko Matsubara Yuka Uchikura Takashi Sugiyama 《International journal of molecular sciences》2021,22(5)
The pathogenesis of preeclampsia begins when a fertilized egg infiltrates the decidua, resulting in implantation failure (e.g., due to extravillous trophoblast infiltration disturbance and abnormal spiral artery remodeling). Thereafter, large amounts of serum factors (e.g., soluble fms-like tyrosine kinase 1 and soluble endoglin) are released into the blood from the hypoplastic placenta, and preeclampsia characterized by multiorgan disorder caused by vascular disorders develops. Successful implantation and placentation require immune tolerance to the fertilized egg as a semi-allograft and the stimulation of extravillous trophoblast infiltration. Recently, exosomes with diameters of 50–100 nm have been recognized to be involved in cell–cell communication. Exosomes affect cell functions in autocrine and paracrine manners via their encapsulating microRNA/DNA and membrane-bound proteins. The microRNA profiles of blood exosomes have been demonstrated to be useful for the evaluation of preeclampsia pathophysiology and prediction of the disease. In addition, exosomes derived from mesenchymal stem cells have been found to have cancer-suppressing effects. These exosomes may repair the pathophysiology of preeclampsia through the suppression of extravillous trophoblast apoptosis and promotion of these cells’ invasive ability. Exosomes secreted by various cells have received much recent attention and may be involved in the maintenance of pregnancy and pathogenesis of preeclampsia. 相似文献
112.
With the development of new specimen preparation techniques and improvements in instrumental resolution, scanning electron microscopy (SEM) became an effective means of studying the three-dimensional organization of the Golgi complex. When specimens prepared by the osmium-DMSO-osmium method are observed with high-resolution SEMs, cis-most cisternae of Golgi stacks appear as sieve-like plates with many small perforations. In some cell types, larger fenestrations are also present. The trans-most cisternae showed a fenestrated or retucular pattern. At the trans-side of Golgi stacks, distinctive structures, such as a well-developed tubular plexus or a single widely extended cisterna, are observed in some types of cells. In lacrimal gland cells, Golgi stacks are linked by an irregular network of anastomosing branches extending throughout the cytoplasm. In these cells, the piled cisternae seemed to be connected to each other either directly within the stack or via cisternae of other stacks. Connections between Golgi stack and rough endoplasmic reticulum (ER) were often found in our SEM observations. In nerve cells, interconnecting tubules arise from rough ER and most often fuse with the rim of the cis-cisternae of Golgi stacks. 相似文献
113.
Akihiko Fujiwara Yoji Koike Keiichi Sasaki Takashi Noji Yoshitami Saito 《Journal of Superconductivity》1994,7(1):123-126
We have investigated the stage-1 iodine-intercalation compounds, whose host materials are Bi2Sr2Ca1–x
Y
x
Cu2O8 (Bi-2212 phase) and Bi1.6Pb0.5Sr1.9–x
La
x
Cu1.05O6 (Bi-2201 phase) with variousx values. In the Bi-2212 phase, it has been found that the change inT
c
through the stage-1 iodine intercalation is due to two effects; a change of the two-dimensionality and an increase in the carrier number. The former effect decreasesT
c
by about 10 K independent of the carrier number of the host sample. The latter effect shifts thex dependence ofT
c
to largerx values by about 0.08, taking account of oxygen release from the host samples during the intercalation process. This result is clear evidence for the occurrence of both the change of two-dimensionality and the increase in carrier number about 0.04 per CuO2 unit due to the charge transfer through the stage-1 iodine intercalation. In the Bi-2201 phase,T
c
decreases by about 10 K through the stage-1 iodine intercalation. 相似文献
114.
Host-plant chemicals stimulating oviposition by a Leguminosae-feeding pierid butterflyColias erate poliographyswere isolated and identified from one of its primary host plants, white clover (Trifolium repens). Females readily deposited eggs in response to methanolic extracts of the plant, and subsequent partition of the extracts with organic solvents revealed that chemical constituents critical for host recognition reside in the water-soluble fraction. Further fractionation of the hydrosoluble fraction by column chromatography led to the separation of an active fraction and two cyanoglucosides, linamarin and lotaustralin. Conspicuous oviposition response was evoked by unidentified polar compound(s), while these cyanoglucosides exerted no stimulatory activity by themselves. However, ovipositing females preferred samples containing either of the two cyanoglucosides. In dual-choice bioassays, significantly more eggs were laid on samples admixed with the cyanoglucosides, suggesting that the cyanoglucosides serve as synergistic oviposition stimulants and could play an important role in host selection. 相似文献
115.
Kazuhiro Saito Mitsuru Yoneyama Mitsuyoshi Saito Keiichi Ikegami Michio Sugi
Takayoshi Nakamura
Mutsuyoshi Matsumoto Yasujiro Kawabata 《Thin solid films》1988,160(1-2):133-137Photoelectric cells based on Langmuir-Blodgett (LB) films were fabricated using dye monolayers as photoconductors and N-docosylpyridinium-di(tetracyanoquinodimethane) (PT) monolayers as one of the electrode materials. It is found that PT films can be used as a wiring material instead of large work function metals such as silver or Ni-Cr. However, in comparison with the photoelectric cells using the conventional metals, a few different properties were observed for those wired with PT. These differences are assignable to the difference between the LB film-metal and the LB film-LB film contacts. 相似文献
116.
117.
Automatic identification of handprinted Hebrew characters is described in this paper. The recognition model devised constitutes a multi-stage system. In the first stage a coarse classifier allocates the input patterns into one of 17 categories, based on the number and the location of end points within predetermined regions in the characters matrix. The second stage uses features extracted in the Hough transform space to classify characters assigned to each of 16 categories. The remaining one category, composed of similar, square-like (rotated L shape) classes, is recognized by structural analysis and a statistical classifier. An additional step of postprocessing is added to compensate for the sensitivity of the Hough transform to the existence of similar classes within some of the categories. Experiments were conducted with a multi-author (40 writers) data base. An average recognition rate of 86.9% was observed for the system. This compared favorably with the results of two other recognition methods. 相似文献
118.
Yoshida Yuzo Mohri Kaneo Yoshino Keiichi 《Industrial Electronics, IEEE Transactions on》1986,(2):132-137
Rugged PWM transistor inverters are expected to be put into practical use for providing high reliability under adverse operating conditions. The bipolar power transistors are more common compared with MOSFET's power transistors in balance between power-handling capability and switching speed. High over current capability, low switching loss, high-speed switching, and high-current gain are requisite functions in the PWM inverter employing bipolar power transistors. These functions are of great concern in the power electronics field. A new PWM transistor inverter which can meet these requirements is presented in this paper. For this purpose, a concept of high-gain pulse-triggered power transistor (PTPT) with amorphous saturable current transformer (CT) is introduced. 相似文献
119.
Ward Lawrence M.; Doesburg Sam M.; Kitajo Keiichi; MacLean Shannon E.; Roggeveen Alexa B. 《Canadian Metallurgical Quarterly》2006,60(4):319
We describe briefly three of our lab's ongoing projects studying the role of neural synchrony in human perception and cognition. These projects arise from two main interests: the role of noise both in human perception and in neural synchrony, and neural synchrony as a basis for integration of functional modules in the brain. Our experimental work on these topics began with a study of the possibility that noise-influenced neural synchrony might be responsible for the fact that small amounts of noise added to weak signals can enhance their detectability (stochastic resonance). We are also studying the role of neural synchrony in attention and consciousness in several paradigms. On the basis of our own and related work by others, we conclude that (1) neural synchrony plays an important role in the integration of functional modules in the brain and (2) neural synchrony is profoundly affected and possibly regulated, in part, by the "noisiness" of the brain. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
120.
Haruki Mizushina Junya Nakamura Yasuhiro Takaki Hiroshi Ando 《Journal of the Society for Information Display》2016,24(12):747-756
A conflict between accommodation and vergence is one possible cause of visual fatigue and discomfort while viewing conventional three‐dimensional displays. Previous studies have proposed the super multi‐view (SMV) display technique to solve the vergence–accommodation conflict, in which two or more parallax images enter the pupil of the eye with highly directional rays. We simultaneously measured accommodative, vergence, and pupillary responses to SMV three‐dimensional displays to examine whether they can reduce the conflict. For comparison, responses to two‐view stereo images and real objects were also measured. The results show that the range of the accommodative response was increased by the SMV images compared with the two‐view images. The slope of the accommodation–vergence response function for the SMV images was similar to that for the real objects rather than the two‐view images. We also found that enhancement of the accommodative range by the SMV images is noticeable with binocular viewing, indicating that vergence‐induced accommodation plays an important role in viewing SMV displays. These results suggest that SMV displays induced a more natural accommodative response than did conventional, two‐view stereo displays. As a result, SMV displays reduced the vergence–accommodation conflict. 相似文献