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   259篇
  免费   10篇
电工技术   3篇
化学工业   92篇
机械仪表   3篇
建筑科学   11篇
矿业工程   1篇
能源动力   8篇
轻工业   26篇
水利工程   1篇
无线电   18篇
一般工业技术   38篇
冶金工业   35篇
自动化技术   33篇
  2023年   6篇
  2022年   16篇
  2021年   19篇
  2020年   10篇
  2019年   14篇
  2018年   9篇
  2017年   4篇
  2016年   13篇
  2015年   5篇
  2014年   7篇
  2013年   17篇
  2012年   10篇
  2011年   15篇
  2010年   9篇
  2009年   8篇
  2008年   7篇
  2007年   8篇
  2006年   10篇
  2005年   6篇
  2004年   4篇
  2003年   1篇
  2002年   7篇
  2001年   2篇
  2000年   4篇
  1999年   3篇
  1998年   12篇
  1997年   7篇
  1996年   7篇
  1995年   3篇
  1994年   2篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1985年   2篇
  1984年   4篇
  1982年   1篇
  1980年   2篇
  1978年   3篇
  1974年   2篇
  1973年   1篇
排序方式: 共有269条查询结果,搜索用时 15 毫秒
241.
Stress urinary incontinence (SUI) is a significant health concern for patients affected, impacting their quality of life severely. To investigate mechanisms contributing to SUI different animal models were developed. Incontinence was induced under defined conditions to explore the pathomechanisms involved, spontaneous recovery, or efficacy of therapies over time. The animal models were coined to mimic known SUI risk factors such as childbirth or surgical injury. However, animal models neither reflect the human situation completely nor the multiple mechanisms that ultimately contribute to the pathogenesis of SUI. In the past, most SUI animal studies took advantage of rodents or rabbits. Recent models present for instance transgenic rats developing severe obesity, to investigate metabolic interrelations between the disorder and incontinence. Using recombinant gene technologies, such as transgenic, gene knock-out or CRISPR-Cas animals may narrow the gap between the model and the clinical situation of patients. However, to investigate surgical regimens or cell therapies to improve or even cure SUI, large animal models such as pig, goat, dog and others provide several advantages. Among them, standard surgical instruments can be employed for minimally invasive transurethral diagnoses and therapies. We, therefore, focus in this review on large animal models of SUI.  相似文献   
242.
As a therapeutic approach, epigenetic modifiers have the potential to enhance the efficacy of chemotherapeutic agents. Protein arginine methyltransferase 5 (PRMT5), highly expressed in lung adenocarcinoma, was identified to be involved in tumorigenesis. In the current study, we examined the potential antineoplastic activity of PRMT5 inhibitor, arginine methyltransferase inhibitor 1 (AMI-1), and cisplatin on lung adenocarcinoma. Bioinformatic analyses identified apoptosis, DNA damage, and cell cycle progression as the main PRMT5-associated functional pathways, and survival analysis linked the increased PRMT5 gene expression to worse overall survival in lung adenocarcinoma. Combined AMI-1 and cisplatin treatment significantly reduced cell viability and induced apoptosis. Cell cycle arrest in A549 and DMS 53 cells was evident after AMI-1, and was reinforced after combination treatment. Western blot analysis showed a reduction in demethylation histone 4, a PRMT5- downstream target, after treatment with AMI-1 alone or in combination with cisplatin. While the combination approach tackled lung cancer cell survival, it exhibited cytoprotective abilities on HBEpC (normal epithelial cells). The survival of normal bronchial epithelial cells was not affected by using AMI-1. This study highlights evidence of novel selective antitumor activity of AMI-1 in combination with cisplatin in lung adenocarcinoma cells.  相似文献   
243.
An adsorption study of Rhodamine B (RB) dye from aqueous solutions was carried out using walnut shells pretreated by different methods. In addition to the effects of the pretreatment, the effects of various parameters like pH, adsorbent dose, contact time, initial dye concentration and temperature on the adsorption of RB was studied. The adsorption process was highly pH dependent and a maximum adsorption was achieved at pH 3.0. The best fit for the rates of dye adsorption was a pseudo-second-order kinetic model with good correlation coefficients (R2>0.99). Langmuir isotherms were used to determine that the maximum loading capacity of the different walnut shells and the RB capacities ranged from 1.451–2.292 mg·g-1. The dye adsorption was also evaluated thermodynamically. Positive standard enthalpy (?H°) values were obtained indicating that the RB adsorption process is endothermic as well as ?G° and ?S° values showed that adsorption process is spontaneous with an increased randomness at the solid-liquid interface. Desorption studies were carried out to explore the feasibility of regenerating the used walnut shells and it was found that 97.71%–99.17% of the retained RB was recovered with 0.1 mol?L-1 NaOH solution. The walnut shells were also successfully used to remove RB from industrial effluents.  相似文献   
244.
245.
The method of transneuronal retrograde transport of the Bartha strain of the swine alpha-herpes virus, pseudorabies virus, was used to identify putative interneurons presynaptic to motoneurons that supply a tail-flick muscle in the rat. We also investigated whether these interneurons also contribute to ascending somatosensory pathways. Two to five days after injection of pseudorabies virus into the left abductor caudae dorsalis muscle, and cholera toxin B into the right somatosensory thalamus and midbrain, rats were perfused and spinal cord sections processed immunohistochemically in a two-step procedure to stain cholera toxin B-immunoreactive cells black and pseudorabies virus-immunoreactive cells brown. At short (two-day) survivals, the first spinal neurons to be pseudorabies virus-immunoreactive were in the ipsilateral abductor caudae dorsalis motoneuron pool (S3-S4) and intermediolateral cell column (T12-L2), with a few (0 to five/section) bilaterally in the intermediate zone and around the central canal (all lumbosacral levels). With longer (three- to four-day) survival, more cells were noted (20-50/section) bilaterally (ipsilateral preponderance) in the dorsal and ventral horns of the lumbosacral cord. Many were in lamina I (marginal layer), while few were in lamina II (substantia gelatinosa). At four- and five-day survivals, the numbers of cells increased (20 to 100/section) bilaterally and now included lamina II. The fact that unilateral rhizotomy at L4-Co1 failed to change the distribution of spinal pseudorabies virus labeling suggests that the labeling was due to retrograde transport via the ventral root. In support, bilateral removal of the lumbar sympathetic ganglia, which receive their preganglionic innervation through the ventral root, reduced pseudorabies virus immunoreactivity throughout the thoracic and rostral lumbar spinal cord. These data indicate that there are (i) direct projections from intermediate and dorsal horn cells to abductor caudae dorsalis motoneurons, and (ii) disynaptic connections from dorsal horn (possibly including lamina II) cells to more ventral last-order interneurons. We also suggest that some lamina II cells are presynaptic to lamina I cells that project directly to abductor caudae dorsalis motoneurons. We observed cholera toxin B-immunoreactive cells (five to 20/section) in the expected locations (contralateral lamina I, deep dorsal horn and intermediate zone; lateral spinal nucleus bilaterally). Double-labeled (i.e. pseudorabies virus- and cholera toxin B-immunoreactive) neurons were only occasionally seen in the lateral spinal nucleus and were absent in the spinal gray matter, indicating that segmental interneurons do not collateralize in long ascending sensory pathways to the midbrain and somatosensory thalamus.  相似文献   
246.
247.
The relationships between angiotensin-converting enzyme (ACE) gene insertion (I) / deletion (D) polymorphism and left ventricular hypertrophy induced by hypertension or idiopathic hypertrophic cardiomyopathy have been studied. However, little is known about the association between this polymorphism and left ventricular hypertrophy induced by volume overload. The relationship between left ventricular hypertrophy and the ACE gene I/D polymorphism was examined in 80 maintenance hemodialysis patients (mean age: 60.1+/-1.4 years). Multivariate regression analysis showed that the left ventricular mass index calculated by M-mode echocardiography was associated with serum creatinine (p = 0.040), male gender (p = 0.027), antihypertensive drug treatment (p = 0.026), weight gain between hemodialysis (p = 0.018) and mean blood pressure after hemodialysis (p=0.010), but not with ACE I/D genotype (p = 0.69). These findings suggest that although hemodialysis patients seem to be under volume overload, ACE genotype may not be involved in their left ventricular hypertrophy. Hypertension and other factors related to renal failure are involved in the left ventricular hypertrophy in chronic hemodialysis patients.  相似文献   
248.
Preliminary observations from one nutrition awareness project--Approaches to Failure to Thrive--in progress in the Ngaanyatjarra Pitjantjatjara Yankunytjatjara region of central Australia are discussed, current strategies are listed and the need for multi-faceted solutions emphasised. A more rigorous quantitative evaluation is recommended, within the constraints of funding and access to data.  相似文献   
249.
250.
Duchenne muscular dystrophy (DMD) is caused by the absence of full-length dystrophin molecules in skeletal muscle fibers. In normal muscle, dystrophin is found along the length of the sarcolemma where it links the intracellular actin cytoskeleton to the extracellular matrix, via the dystrophin-associated protein (DAP) complex. Several years ago, an autosomal homologue to dystrophin, termed utrophin, was identified and shown to be expressed in a variety of tissues, including skeletal muscle. However, in contrast to the localization of dystrophin in extrajunctional regions of muscle fibers, utrophin preferentially accumulates at the postsynaptic membrane of the neuromuscular junction in both normal and DMD adult muscle fibers. Since it has recently been suggested that the upregulation of utrophin might functionally compensate for the lack of dystrophin in DMD, considerable interest is now directed toward the elucidation of the various regulatory mechanisms presiding over expression of utrophin in normal and dystrophic skeletal muscle fibers. In this review, we discuss some of the most recent data relevant to our understanding of the impact of myogenic differentiation and innervation on the expression and localization of utrophin in skeletal muscle fibers.  相似文献   
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