首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1044篇
  免费   46篇
  国内免费   1篇
电工技术   12篇
化学工业   224篇
金属工艺   19篇
机械仪表   18篇
建筑科学   32篇
矿业工程   4篇
能源动力   44篇
轻工业   101篇
水利工程   10篇
石油天然气   9篇
无线电   108篇
一般工业技术   186篇
冶金工业   159篇
原子能技术   19篇
自动化技术   146篇
  2023年   7篇
  2022年   33篇
  2021年   48篇
  2020年   8篇
  2019年   32篇
  2018年   34篇
  2017年   35篇
  2016年   33篇
  2015年   19篇
  2014年   47篇
  2013年   80篇
  2012年   47篇
  2011年   69篇
  2010年   45篇
  2009年   51篇
  2008年   46篇
  2007年   35篇
  2006年   31篇
  2005年   13篇
  2004年   23篇
  2003年   21篇
  2002年   19篇
  2001年   21篇
  2000年   9篇
  1999年   17篇
  1998年   35篇
  1997年   27篇
  1996年   16篇
  1995年   17篇
  1994年   22篇
  1993年   17篇
  1992年   7篇
  1991年   6篇
  1990年   6篇
  1989年   6篇
  1988年   4篇
  1987年   6篇
  1986年   7篇
  1985年   12篇
  1982年   8篇
  1981年   9篇
  1980年   7篇
  1979年   7篇
  1978年   3篇
  1977年   10篇
  1976年   7篇
  1974年   3篇
  1973年   4篇
  1972年   7篇
  1971年   3篇
排序方式: 共有1091条查询结果,搜索用时 15 毫秒
81.
The application of cross‐corpus for speech emotion recognition (SER) via domain adaptation methods have gain high acknowledgment for developing good robust emotion recognition systems using different corpora or datasets. However, the issue of cross‐lingual still remains a challenge in SER and needs more attention to resolve the scenario of applying different language types in both training and testing. In this paper, we propose a triple attentive asymmetric convolutional neural network to address the recognition of emotions for cross‐lingual and cross‐corpus speech in an unsupervised approach. The proposed method adopts the joint supervision of softmax loss and center loss to learn high power discriminative feature representations for target domain via the use of high quality pseudo‐labels. The proposed model uses three attentive convolutional neural networks asymmetrically, where two of the networks are used to artificially label unlabeled target samples as a result of their predictions from training on source labeled samples and the other network is used to obtain salient target discriminative features from the pseudo‐labeled target samples. We evaluate our proposed method on three different language types (i.e., English, German, and Italian) data sets. The experimental results indicate that, our proposed method achieves higher prediction accuracy over other state‐of‐the‐art methods.  相似文献   
82.
With the number of deaths due to stroke decreasing, more individuals are forced to live with crippling disability resulting from the stroke. To date, no therapeutics exist after the first 4.5 h after the stroke onset, aside from rest and physical therapy. Following stroke, a large influx of astrocytes and microglia releasing proinflammatory cytokines leads to dramatic inflammation and glial scar formation, affecting brain tissue's ability to repair itself. Pathological conditions, such as a stroke, trigger neural progenitor cells (NPCs) proliferation and migration toward the damaged site. However, these progenitors are often found far from the cavity or the peri‐infarct tissue. Poststroke tissue remodeling results in a compartmentalized cavity that can directly accept a therapeutic material injection. Here, this paper shows that the injection of a porous hyaluronic acid hydrogel into the stroke cavity significantly reduces the inflammatory response following stroke while increasing peri‐infarct vascularization compared to nonporous hydrogel controls and stroke only controls. In addition, it is shown that the injection of this material impacts NPCs proliferation and migration at the subventricular zone niche and results, for the first time, in NPC migration into the stroke site.  相似文献   
83.
The convergence of materials science, electronics, and biology, namely bioelectronic interfaces, leads novel and precise communication with biological tissue, particularly with the nervous system. However, the translation of lab-based innovation toward clinical use calls for further advances in materials, manufacturing and characterization paradigms, and design rules. Herein, a translational framework engineered to accelerate the deployment of microfabricated interfaces for translational research is proposed and applied to the soft neurotechnology called electronic dura mater, e-dura. Anatomy, implant function, and surgical procedure guide the system design. A high-yield, silicone-on-silicon wafer process is developed to ensure reproducible characteristics of the electrodes. A biomimetic multimodal platform that replicates surgical insertion in an anatomy-based model applies physiological movement, emulates therapeutic use of the electrodes, and enables advanced validation and rapid optimization in vitro of the implants. Functionality of scaled e-dura is confirmed in nonhuman primates, where epidural neuromodulation of the spinal cord activates selective groups of muscles in the upper limbs with unmet precision. Performance stability is controlled over 6 weeks in vivo. The synergistic steps of design, fabrication, and biomimetic in vitro validation and in vivo evaluation in translational animal models are of general applicability and answer needs in multiple bioelectronic designs and medical technologies.  相似文献   
84.
Self-assembly guided by molecular recognition has in the past been employed to assemble nanoparticle superstructures like hypercrystals or nanoparticle molecules. An alternative approach, the direct molecule-by-molecule assembly of nanoscale superstructures, was demonstrated recently. Here we present a hybrid approach where we first assemble a pattern of binding sites one-by-one at a surface and then allow different nanoparticles to attach by self-assembly. For this approach, biotin bearing DNA oligomers were picked up from a depot using a cDNA strand bound to an AFM tip. These units were deposited in the target area by hybridization, forming a recognition pattern on this surface. Fluorescent semiconductor nanoparticles conjugated with streptavidin were allowed to assemble on this scaffold and to form the final nanoparticle superstructures.  相似文献   
85.
Distributed uplink scheduling and rate control in CDMA networks are considered in the case of adaptive antenna arrays present at the base station. The system model with omnidirectional antennas is generalized to the case where adaptive antenna arrays are deployed. Rate control in a probabilistic manner is investigated. Long-term control by the base station through token bucket constraints is incorporated in the system. Monte Carlo simulation results show considerable improvement when adaptive antenna arrays are used. Optimization of the rate transition probabilities is treated in the special case of on–off scheduling.  相似文献   
86.
In our efforts to identify new loci responsible for non-syndromic autosomal recessive forms of deafness, DFNB loci, we have pursued the analysis of large consanguineous affected families living in geographically isolated areas. Here, we report on the study of a Lebanese family comprising nine members presenting with a pre-lingual severe to profound sensorineural isolated form of deafness. Linkage analysis led to the characterization of a new locus, DFNB21, which was assigned to chromosome 11q23-25. Already mapped to this chromosomal region was TECTA. This gene encodes alpha-tectorin, a 2155 amino acid protein which is a component of the tectorial membrane. This gene recently has been shown to be responsible for a dominant form of deafness, DFNA8/12. Sequence analysis of the TECTA gene in the DFNB21-affected family revealed a G to A transition in the donor splice site (GT) of intron 9, predicted to lead to a truncated protein of 971 amino acids. This establishes that alpha-tectorin mutations can be responsible for both dominant and recessive forms of deafness. Comparison of the phenotype of the DFNB21 heterozygous carriers with that of DFNA8/12-affected individuals supports the hypothesis that the TECTA mutations which cause the dominant form of deafness have a dominant-negative effect. The present results provide genetic evidence for alpha-tectorin forming homo- or heteromeric structures.  相似文献   
87.
88.
BACKGROUND: A patient's likelihood of dying from breast cancer or another cause can be assessed with competing risks analyses. METHODS: Data for a cohort of 678 patients with primary invasive breast cancer accrued from 1971 to 1990, updated to 1995, included cause of death (e.g., breast cancer vs. other cause). We investigated the effects of age, tumor size, nodal status, ER, PgR, and adjuvant therapy (hormones, chemotherapy, radiotherapy) on type of death and time to death for patients of all ages and for those over the age of 65 years. RESULTS: Although there were no significant univariate differences in breast cancer death rates by age group (P=0.94), more patients over the age of 65 years died from other causes (41/207 [20%] of those older than 65 years vs. 16/471 [3%] of those younger than 65 years; P <.001). In competing risks analyses, older age was associated with non-breast cancer death, whereas larger tumor size was associated with breast cancer death. PgR was positively, and nodal status negatively, associated with survival, regardless of type. In the older patient group, the competing risks analyses identified similar effects for age and tumor size; in addition, higher ER assay values were less likely to be associated with breast cancer death. CONCLUSIONS: With increased lifespan, there will be more breast cancer cases in women older than 65 years; we have shown that women in this group have more non-breast cancer deaths. It becomes important, then, to delineate differential effects of prognostic factors on competing causes of death.  相似文献   
89.
Human infants (aged 12–32 mo old) and adults learned a delayed nonmatching-to-sample (DNMS) task and single- and multiple-pair discrimination tasks using nonverbal procedures previously used with monkeys. Infants learned discriminations rapidly and at a young age (12 mo), but they required prolonged training and maturation before learning the DNMS task. Adults learned all tasks rapidly. After learning the DNMS task to criterion, memory performance declined systematically in an inverse relation to age. The dissociation in ability of infants on the DNMS vs discrimination tasks closely resembles the dissociation previously reported with infant monkeys (J. Bachevalier & M. Mishkin, 1984). Results from both infant humans and monkeys support a neurocognitive maturational model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
90.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号