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251.
《Reproductive biology》2023,23(1):100712
Preeclampsia (PE) is a pregnancy-specific disorder and a significant contributor to maternal, fetal and neonatal morbidity and mortality worldwide. Its pathogenesis is generally accepted as insufficient trophoblast invasion of the maternal endometrium and inadequate remodeling of the maternal spiral arteries. These impairments lead to elevated levels of hypoxia and oxidative stress. Autophagy has become a highly researched field in obstetrics, and this process may be essential for preimplantation development beyond the four- and eight-cell stages, and for blastocyst survival, extra-villous trophoblast functions, invasion and vascular remodeling. Several studies have shown that autophagy activation, shown by an increase in autophagy vacuoles or microtubule-associated protein 1 A/1B-light chain 3 (LC3) dots, was more common in PE than in normal pregnancy. Thus, changes in autophagic status are seen in preeclamptic placentas. MicroRNA-141–3p (miR-141–3p), a multifunctional miRNA, is involved in a variety of physiological and pathological processes, including PE and autophagy. However, the influence of miR-141–3p on autophagy regulation in trophoblast cells has yet to be described. Therefore, the objective of our study was to investigate the role of miR-141–3p in autophagy induced by hypoxia in human placental trophoblast cells. Our results found that hypoxia induced autophagy in trophoblast cells and dramatically elevated the expression of miR-141–3p. Overexpression of miR-141–3p improved autophagic activity, whereas low expression of miR-141–3p inhibited autophagic activity. Therefore, our data demonstrated that miR-141–3p promoted hypoxia-induced autophagy in placental trophoblast cells, which may be related to the development of preeclampsia.  相似文献   
252.
253.
肯氏相思~(60)Co-r辐照诱变研究   总被引:1,自引:0,他引:1  
采用不同剂量(3000、5000、7000Rad)(60)Co-r辐照肯氏相思种子,选育出诱变化株(M1),以M1的种子(M2)扩种试验。观测M1和M2代的形态、物候,并测定过氧化物酶同功酶带谱、酶活性、蛋白质含量,结果表明,各处理的优株与对照都存在差异。在相同生态条件下,M1代林木生长量和民代地上部生物量分别高于对照见11.48%~21.64%和14.62%~73.98%,以5000Rad辐照剂量最优,其次为7000Rad。访变个体后代表现树干直、花果期提早和种子小。  相似文献   
254.
Cerium doped ZSM-5 (Ce−ZSM-5) as an environmentally benign and reusable catalyst for the construction of acridines in aqueous medium. This method produced corresponding acridines with good yields and shorter reaction times. Also avoids the use of hazardous solvents and involves a simple work-up process. The solid catalyst was prepared by doping Ce ions with ZSM-5 (Zeolite Socony Mobil-5) and confirmed by XRD, BET SA-PSD and SEM. The synthesised acridine derivatives were confirmed by 1H-NMR, 13C-NMR and FT-IR spectroscopic data. The docking studies of the synthesised compounds are performed by the PyRx auto dock tool against DNA gyrase protein. The products 5a and 6d are found to be the best fit ligands against DNA gyrase protein.  相似文献   
255.
The crystal structure and morphology of Ce3+‐doped SrSnO3 materials prepared using the solid‐state reaction method were extensively characterized using experimental techniques. X‐Ray diffraction results show that the cerium substitution of strontium does not change the structure of the strontium stannate. Raman spectroscopy was used to investigate the microstructures and lattice vibrations. Environmental scanning electron microscopy images showed that phosphors aggregate and their particles form irregular shapes. SrSnO3 exhibits an intense green emission with a broad band originating from the 5d1 → 4f1 transition of cerium. It was observed that, after exposure to beta‐irradiation, the glow curve of this material has two broad thermoluminescence peaks, one centered at ~ 127°C and the other at ~ 245°C for a heating rate of 5 K/s. The kinetic parameters, which include the frequency factor and the activation energy of the material, were calculated using Chen's method, after beta‐irradiation. The fading and reusability of the phosphor were also studied and it was found that the phosphor is suitable for radiation dosimetry. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
256.
Solution combustion synthesized ZnO nanoparticles that were Ce doped, Dy doped or co-doped at varying dopant concentrations were characterized for their microstructural, optical, and photoluminescence (PL) characteristics. The synthesized nanoparticles matched the standard hexagonal wurtzite structure of ZnO. The lattice fringes in the high-resolution transmission electron micrographs and the bright spotty rings in the selected area electron diffraction patterns authenticated the high crystallinity of the nanoparticles. The diffuse reflectance spectroscopy resolved the energy bandgap for the undoped ZnO as 3.18 eV, which decreased upon doping and co-doping. A sharp narrow ultraviolet emission peak at ~398 nm that originated from excitonic recombination was found in the PL spectra of the nanoparticles. The visible emission peaks in the PL spectra were assigned to the f–d and f–f electron transitions of Ce3+ and Dy3+ ions, respectively, in addition to different native defects in ZnO. The visible emissions (blue, yellow, and red) improved upon (Ce, Dy) co-doping, therefore (Ce, Dy) co-doped ZnO nanoparticles can be considered a promising luminescent material for the development of energy-saving light sources.  相似文献   
257.
Yongfu Teng 《Luminescence》2019,34(4):432-436
In the Ba9Lu2Si6O24 (BLS) host, Ce3+ shows cyan emissions peaking at 490 nm under 400 nm excitations. BLS:Tb3+ only can be effectively excited by 254 nm light and gives rise to green emissions at 553 nm. However, both the cyan and green emissions can be obtained in BLS:Ce3+,Tb3+ under 400 nm excitations due to effective energy transfers from Ce3+ to Tb3+. BLS:Mn2+ shows red emissions peaking at 610 nm under 414 nm excitations. By co‐doping Ce3+, Tb3+ and Mn2+, tunable full‐color emissions were obtained. The BLS:0.3Ce3+,0.6Tb3+,0.15Mn2+ single phosphor exhibits a white light with a high color rendering index of 85 and a correlated color temperature of 5480 K under 400 nm excitation.  相似文献   
258.
生长因子是细胞间通讯的语言之一,是调节细胞生长的重要媒介物。越来越多的证据证明:生长因子是多功能多肽,一种组织内细胞群落的生长控制需要通过一系列生长因子与  相似文献   
259.
Angelica Sinensis polysaccharide cerium (ASP−Ce) was prepared by Angelica Sinensis polysaccharide (ASP) and cerium ammonium nitrate (NH4)2Ce(NO3)6. and its morphology, and solid structure was investigated. The antioxidant activity of the ASP−Ce complex in vitro was evaluated. The antioxidant activity of ASP−Ce complex in vitro was evaluated by the scavenging activity of 2,2-diphenyl-1-picrylhyrazyl radical (DPPH), hydroxyl radical (⋅OH) and superoxide anion radical ( ⋅). The results showed that the ASP−Ce had the more ordered structure for inserting the Ce4+ into the polymer chain of ASP and there was little change in the conformation of the polysaccharide from Ce4+. Three free radical scavenging experiments proved that ASP−Ce had better antioxidant capacity than of ASP, especially on DPPH, and then on ⋅. The scavenging rate of ASP−Ce at 1.0 mg/mL on DPPH reached 71.6 %. Therefore, these results provide references for the further development and utilization of rare earth-polysaccharide.  相似文献   
260.
Since the first reported birth following in vitro fertilization in 1978, further developments in assisted reproductive technology (ART) treatments have produced at least 8 million babies worldwide. Cryopreservation techniques have been central to this treatment revolution, increasing cycle efficacy by allowing the banking of supernumerary embryos for later use, as well as affording the prospective patient more time in cases of anticipated fertility decline. Additionally, these techniques have demonstrated promise in increasing the safety of ART treatments, by reducing complications such as ovarian hyperstimulation, leading to increased support for the introduction of a ‘total freeze’ policy involving deferred embryo transfers. Importantly, the effective cryopreservation of both spermatozoa and oocytes has permitted long-term gamete storage without degradation of quality, facilitating gamete banking for personal use or fertility treatment. Here, we will summarise the indications for applying cryopreservation methods in clinical reproductive medicine, highlighting recent technical advances and examining the evidence base that supports the continued use of cryopreservation in ART.  相似文献   
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