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   645篇
  免费   49篇
  694篇
  2024年   2篇
  2023年   24篇
  2022年   20篇
  2021年   21篇
  2020年   19篇
  2019年   18篇
  2018年   30篇
  2017年   39篇
  2016年   30篇
  2015年   26篇
  2014年   38篇
  2013年   59篇
  2012年   39篇
  2011年   42篇
  2010年   33篇
  2009年   21篇
  2008年   32篇
  2007年   38篇
  2006年   22篇
  2005年   21篇
  2004年   23篇
  2003年   18篇
  2002年   10篇
  2001年   8篇
  2000年   4篇
  1999年   4篇
  1998年   5篇
  1997年   7篇
  1996年   3篇
  1995年   5篇
  1994年   5篇
  1993年   2篇
  1992年   2篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1976年   1篇
  1972年   2篇
  1969年   2篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
  1950年   1篇
  1947年   1篇
排序方式: 共有694条查询结果,搜索用时 0 毫秒
91.
Research on syphilis, a sexually transmitted infection caused by the non-cultivatable spirochete Treponema pallidum, has been hampered by the lack of an inbred animal model. We hypothesized that Toll-like receptor (TLR)-dependent responses are essential for clearance of T. pallidum and, consequently, compared infection in wild-type (WT) mice and animals lacking MyD88, the adaptor molecule required for signaling by most TLRs. MyD88-deficient mice had significantly higher pathogen burdens and more extensive inflammation than control animals. Whereas tissue infiltrates in WT mice consisted of mixed mononuclear and plasma cells, infiltrates in MyD88-deficient animals were predominantly neutrophilic. Although both WT and MyD88-deficient mice produced antibodies that promoted uptake of treponemes by WT macrophages, MyD88-deficient macrophages were deficient in opsonophagocytosis of treponemes. Our results demonstrate that TLR-mediated responses are major contributors to the resistance of mice to syphilitic disease and that MyD88 signaling and FcR-mediated opsonophagocytosis are linked to the macrophage-mediated clearance of treponemes.  相似文献   
92.
A huge amount of residue is released every year in agricultural and food industries. If this waste is valorised properly, it would be very beneficial from both economic and environmental aspects. Recently, seeds of oil crops have been getting great interest due to their waste rich in a great variety of lipophilic and hydrophilic phytochemicals. On the other hand, oilseed processing by-products comprise approximately 35 millions of tons seed for oil in European Union. Therefore, this remarkable amount of residue should be considered as a resource from waste to health. The purpose of the present research is to introduce the types of oilseed by-product and their high added value phytochemicals by summarizing the recent studies on the valorization of different wastes of several oilseed crops. This research also supplies an overview of the oilseed sources with their botanical names, production regions and target phytochemical ingredients. Moreover, further remarks with some certain concerns are discussed.  相似文献   
93.
The risk of exhaustion of natural resources and raw materials have given rise to emerging trends such as recycling of food waste. From the economical and ecological points of view, conversion of biowaste to high added value compounds has been getting great attention among the science and commercial entities. Due to their high-added value phytochemicals, agricultural and food residues have been a great significant to the researchers around the world. This study focuses on the valorisation of cake derived from sesame oil processing. If the very valuable non-nutrient phytochemicals in sesame cake are not evaluated properly, they would be consumed as just animal feed or fertilizers. They might be employed as antiaging (in pharmaceutical products), or free radical scavenger (in dietary supplements), or preservative additive against lipid oxidation (in fat containing food products). This review article aims to present pharmacological and therapeutic effects of sesame cake extract by pointing out its application in pharmaceutical, cosmetic and food industries.  相似文献   
94.
Myelination in the central nervous system takes place predominantly during the postnatal development of humans and rodents by myelinating oligodendrocytes (OLs), which are differentiated from oligodendrocyte progenitor cells (OPCs). We recently reported that Sox2 is essential for developmental myelination in the murine brain and spinal cord. It is still controversial regarding the role of Sox2 in oligodendroglial lineage progression in the postnatal murine spinal cord. Analyses of a series of cell- and stage-specific Sox2 mutants reveal that Sox2 plays a biphasic role in regulating oligodendroglial lineage progression in the postnatal murine spinal cord. Sox2 controls the number of OPCs for subsequent differentiation through regulating their proliferation. In addition, Sox2 regulates the timing of OL differentiation and modulates the rate of oligodendrogenesis. Our experimental data prove that Sox2 is an intrinsic positive timer of oligodendroglial lineage progression and suggest that interventions affecting oligodendroglial Sox2 expression may be therapeutic for overcoming OPC differentiation arrest in dysmyelinating and demyelinating disorders.  相似文献   
95.
96.
Experimental design is a form of process analysis in which certain factors are selected to obtain the desired responses of interest. It may also be used for the determination of the effects of various independent factors on a dependent factor. The bioengineering discipline includes many different areas of scientific interest, and each study area is affected and governed by many different factors. Briefly analyzing the important factors and selecting an experimental design for optimization are very effective tools for the design of any bioprocess under question. This review summarizes experimental design methods that can be used to investigate various factors relating to bioengineering processes. The experimental methods generally used in bioengineering are as follows: full factorial design, fractional factorial design, Plackett–Burman design, Taguchi design, Box–Behnken design and central composite design. These design methods are briefly introduced, and then the application of these design methods to study different bioengineering processes is analyzed.  相似文献   
97.
98.
Williams Syndrome (WS) is a rare genetic multisystem disorder that occurs because of a deletion of approximately 25 genes in the 7q11.23 chromosome region. This causes dysmorphic facial appearances, multiple congenital cardiovascular defects, delayed motor skills, and abnormalities in connective tissues and the endocrine system. The patients are mostly diagnosed with mild to moderate mental retardation, however, they have a hyper sociable, socially dis-inhibited, and outgoing personality, empathetic behavior, and are highly talkative. Oxytocin (OT), a neuropeptide synthesized at the hypothalamus, plays an important role in cognition and behavior, and is thought to be affecting WS patients’ attitudes at its different amounts. Oxytocin receptor gene (OXTR), on chromosome 3p25.3, is considered regulating oxytocin receptors, via which OT exerts its effect. WS is a crucial disorder to understand gene, hormone, brain, and behavior associations in terms of sociality and neuropsychiatric conditions. Alterations to the WS gene region offer an opportunity to deepen our understandings of autism spectrum disorder, schizophrenia, anxiety, or depression. We aim to systematically present the data available of OT/OXTR regulation and expression, and the evidence for whether these mechanisms are dysregulated in WS. These results are important, as they predict strong epigenetic control over social behavior by methylation, single nucleotide polymorphisms, and other alterations. The comparison and collaboration of these studies may help to establish a better treatment or management approach for patients with WS if backed up with future research.  相似文献   
99.
Obesity, mainly characterized by the excess fat storage, is a global health problem resulting in serious morbidity and mortality. Identification of molecular mechanisms in adipogenic differentiation pathway might lead to development of new strategies for diagnosis, prevention and therapy of obesity and associated diseases. Discovery of new genes and proteins in the differentiation pathway could help to understand the key specific regulators of the adipogenesis. Cytoglobin (Cygb), identified as a new globin family member protein, is expressed in various tissues. Although its interaction with oxygen and nitric oxide indicates the potential role in antioxidant pathways, the exact role remains unclear. In the current study, expression level of Cygb was determined in proliferating and differentiating 3T3-F442A cells by gene expression and protein expression analysis. Results revealed that Cygb expression up-regulated in differentiated cells in parallel with adipogenic differentiation markers; PPARγ, CEBPα and FABP4 expressions. Besides, Cygb overexpression in preadipocytes contributed to the adipogenic differentiation as verified by detection of higher lipid droplets and increased PPARγ, CEBPα and FABP4 expressions with respect to control cells. These findings will shed light on the unknown roles of Cygb in adipogenesis and obesity.  相似文献   
100.
A new karyotype for blind mole rats was recorded in Tunceli province in Eastern Turkey. The karyotype contained 44 chromosomes, including 13 biarmed pairs, 7 acrocentric pairs, and one heteromorphic pair with a submetacentric and an acrocentric homologue in the autosomal complement (FNa=69). The X chromosome was submetacentric and the Y chromosome medium-sized subtelocentric (FN=73). Distinct dark centromeric C-bands were observed on most of the biarmed and three pairs of the acrocentric autosomes. The NORs were detected on short arms of three subtelocentric pairs and one acrocentric pair of autosomes. The diploid number of chromosomes and the karyotype characteristics observed are obviously unique among hitherto studied populations of blind mole rats and the complement can be evaluated as a new chromosome race of Nannospalax xanthodon. The distribution ranges of individual chromosome races of the species recorded in Eastern Anatolia are revised and possible interracial hybridization is discussed in respect of the finding of a new race.  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