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1.
Bulletin of Environmental Contamination and Toxicology - Heavy metals pollution and salinization of soils are widely distributed in agricultural soils. This study investigated the effects of five...  相似文献   
2.
目的 对肝门空肠吻合加空肠胆支造瘘术与加胆支防返流瓣成形术 ,这两种术式的优缺点进行比较。方法 A组 2 4例胆道闭锁行肝门空肠Roux Y吻合 ,空肠胆支造瘘术。B组为另外 2 4例行肝门空肠Roux Y吻合 ,空肠胆支防返流瓣成形术。对这两组术后情况进行回顾性分析。结果 A组 10例存活 ,无黄疸 9例 ,最大的已 9岁 ,1例出现肝脾肿大、食道静脉曲张。 1例带黄疸存活并出现门脉高压 ,现已 8岁。B组存活 10例 ,其中无黄疸存活 8例。结论 两组病例术后排胆汁 (或排黄绿色大便 )时间、胆管炎发生次数等临床表现进行了比较。排胆汁时间相似 ,无显著差异。术后胆管炎发生率也无显著差异。两种手术都有防返流作用 ,而空肠胆支防返流瓣免除了经皮肤的空肠胆支造瘘。  相似文献   
3.
目的 :探讨川芎嗪对凝血酶诱导的血管内皮细胞释放vWF、组织因子途径抑制物及表达组织因子的影响。方法 :传代培养的新生牛主动脉内皮细胞取上清液测vWF、组织因子途径抑制物 ;细胞冻融液测组织因子的活性。结果 :①与对照相比凝血酶能明显促进内皮细胞表达组织因子 ( 1 2 .8± 2 .43,P <0 .0 0 1 )和释放vWF( 1 8.43± 3.2 0 ,P <0 .0 0 1 ) ,川芎嗪则抑制组织因子表达 ( 0 .52± 0 .1 3,P <0 .0 0 1 )抑制vWF释放 ( 1 3.3± 5.6,P <0 .0 1 ) ;②与对照相比 ( 2 .64± 0 .93) ,凝血酶明显抑制内皮细胞释放组织因子途径抑制物 ( 0 .81± 0 .52 ,P <0 .0 0 1 ) ,但川芎嗪无明显作用 ,也不能抑制凝血酶的效应。结论 :川芎嗪可以抑制内皮细胞表达组织因子和释放vWF。  相似文献   
4.
目的为对肝门空肠吻合加空肠胆支造瘘术与加胆支防返流瓣成形术,这两种术式的优缺点进行比较.方法48例胆道闭锁分为两组.A组24例胆道闭锁行肝门空肠Roux-Y吻合,空肠胆支造瘘术.B组为另外24例行肝门空肠Roux-Y吻合,空肠胆支防返流瓣成形术.对这两组术后情况进行回顾性分析.结果A组9例存活,均无黄疸,最长的已9年,1例出现肝脾肿大、食道静脉曲张.现已8岁.B组存活10例,其中无黄疸存活8例.结论两组病例术后排胆汁(或排黄绿色大便)时间、胆管炎发生次数等临床表现进行比较.排胆汁时间相似,无显著差异.术后胆管炎发生率也无显著差异.  相似文献   
5.
目的:观测高血压及冠心病患者血浆TF活性与TFPI活性的变化。方法:采用二步法测定血浆TF活性;以Sandset发色底物法测定TFPI活性。结果:高血压与冠心病患者血浆TF与TFPI活性均高于正常对照组(P<0.05)。结论:凝血功能亢进可能参与了高血压、冠心病形成,提示血浆TF和TFPI活性测定值可作为高血压、冠心病辅助性诊断指标。  相似文献   
6.
Excision repair cross complementing 1 (ERCC1), ribonucleotide reductase M1 (RRM1), β-tubulin III (TUBB3), thymidylate synthetase (TYMS), and topoisomerase IIα (TOP2A) genes have been shown to be associated with the pathogenesis and prognosis of various types of carcinomas; however, their roles in breast cancer have not been fully validated. In this study, we evaluated the correlations among these biomarkers and the associations between their expression intensity and the clinicopathological characteristics to investigate whether the above genes are underlying biomarkers for patients with breast cancer.Ninety-seven tissue specimens collected from breast cancer patients. The expression levels of these biomarkers were measured by the multiplex branched DNA liquidchip (MBL) technology and clinicopathological characteristics were collected simultaneously.The expression levels of ERCC1, TUBB3, TYMS, and TOP2A were significantly associated with the characteristics of menopausal status, tumor size, lymph node metastasis, hormone receptor status, triple-negative status, Ki-67 index, and epidermal growth factor receptor. The expression intensity of ERCC1 negatively associated with that of TUBB3 and TYMS, and positively associated with that of RRM1. The expression intensity of TOP2A positively associated with that of TYMS. Hierarchical clustering analysis and difference test indicated that breast cancer with higher levels of TUBB3, TYMS, and TOP2A, as well as lower levels of ERCC1 and RRM1 tended to have higher histological grade and Ki-67 index.Our studies showed that ERCC1, TYMS, TUBB3, and TOP2A may be potential biomarkers for prognosis and individualized chemotherapy guidance, while there may be interactions between ERCC1 and RRM1, or TUBB3, or TYMS, as well as between TOP2A and TYMS in pathogenesis and development of breast cancer.  相似文献   
7.
BackgroundThe metabolic syndrome (MetS) represents a clustering of risk factors for cardiovascular diseases that includes abdominal obesity, hypertension, dyslipidemia, and insulin resistance.ObjectivesThe objective of this study was to reassess the parent-offspring association of MetS since the available findings are still controversial.MethodsThe Cochrane Library, PubMed, Embase, and Web of Science databases were searched to identify relevant articles. All studies comparing MetS status between the offspring of parents with MetS and offspring of parents without MetS were included in the analysis.ResultsA total of 9 studies met the inclusion criteria and they were analyzed. Offspring of at least 1 parent with MetS had a higher risk of MetS (OR 3.88, 95% CI 2.58–5.83, p < 0.001). Sons and daughters of fathers with MetS both had a higher risk of MetS (OR 2.31, 95% CI 1.70–3.12, p < 0.001, and OR 1.73, 95% CI 1.37–2.18, p < 0.001, respectively). Sons and daughters of mothers with MetS both had a higher risk of MetS (OR 1.95, 95% CI 1.37–2.76, p = 0.0002, and OR 1.91, 95% CI 1.54–2.35, p < 0.001, respectively).ConclusionThis meta-analysis showed that there is a higher risk of MetS in the offspring of parents with MetS. However, there was no differential association of MetS according to gender and/or age of the offspring.  相似文献   
8.
Sm-doped BiFeO3 (Bi0.85Sm0.15FeO3, or BSFO) thin films were fabricated on (001) SrTiO3(STO) substrates by pulsed laser deposition (PLD) over a range of deposition temperatures (600 °C, 640 °C and 670 °C). Detailed analysis of their microstructure via X-ray diffraction (XRD) and transmission electron microscopy (TEM) shows the deposition temperature dependence of ferroelectric (FE) and antiferroelectric (AFE) phase formation in BSFO. The Sm dopants are clearly detected by high-resolution scanning transmission electron microscopy (HR-STEM) and prove effective in controlling the ferroelectric properties of BSFO. The BSFO (Tdep = 670 °C) presents larger remnant polarization (Pr) than the other two BSFO (Tdep = 600 °C, 640 °C) and pure BiFeO3 (BFO) thin films. This study paves a simple way for enhancing the ferroelectric properties of BSFO via deposition temperature and further promoting BFO practical applications.

Sm-doped BiFeO3 (Bi0.85Sm0.15FeO3) thin films were fabricated on (001) SrTiO3 substrates by PLD over a range of deposition temperatures. The Sm dopants are clearly detected by high-resolution scanning transmission electron microscopy.

As a promising alternative lead-free piezoelectric material, BiFeO3 (BFO) thin films have attracted enormous research interest due to their remarkable multiferroic properties and piezoelectric response.1–4 However, the high leakage current and large coercive field are factors limiting the extensive use of BFO.5 Since the polarization is mainly induced by the Bi3+ ions, various rare-earth elements (e.g., La, Nd, Sm, and Gd) have been doped into the Bi-site to improve the overall ferroelectric response.6–8 According to the site-engineering concept, the doping of foreign elements causes chemical pressure and controls the volatility of Bi atoms in BFO systems.9,10 The structural information of rare-earth-doped BFO (Re-BFO) systems is therefore upgraded and a preliminary phase diagram is proposed.11–14Sm-doped BFO (Bi1−xSmxFeO3, BSFO) thin film has attracted research attention, due to the narrow concentration range at room temperature.15 It shows ferroelectric (FE) rhombohedral to antiferroelectric (AFE) orthorhombic phase transitions as the Sm doping amount increases. Morphotropic phase boundary (MPB) appears at around x = 0.13–0.15, and high values of out-of-plane piezoelectric coefficient (d33 ∼ 110 pm V−1) and enhanced dielectric constant at x = 0.14 are reported in such systems.16,17 Structure studies show that three main phase, FE R3c phase, AFE PbZrO3-like phase, and paraelectric Pnma phase, coexist at the MPB composition.18 In this regard, many efforts have been made on the investigation of phase transitions under external stimuli.19,20 However, there are not much work on the structure analysis of BSFO at the atomic-scale level. It will be interesting to investigate the microstructure with high-resolution transmission electron microscopy (TEM) and high-resolution scanning transmission electron microscopy (HR-STEM). The detailed microstructure information will reveal how the Sm dopants distribute in the overall BSFO lattice. In addition, BSFO films in previous studies are mostly prepared by solid phase synthesis and sol–gel method15,20,21 with very few reports using pulsed laser deposition (PLD).17,22 In those prior reports, Sm-doping amounts in films were controlled by changing the composition of the deposition targets. Deposition temperature has been proven as an effective parameter for PLD in controlling the doping amount, thin film microstructure and the related properties. In the Ag-doped ZnO (SZO) system, deposition temperature was directly used to control the density of stacking faults and consequently affect the electrical transport properties.23 Table S1 lists several reported deposition temperatures for Re-BFO thin films, which is in the range of 520 °C to 850 °C. Here, we used three different substrate temperatures, 600 °C, 640 °C and 670 °C, for the BSFO film fabrication via PLD. Pure BFO film was also grown as a reference sample for comparison. Besides the detailed microstructure, the corresponding ferroelectric property measurements were conducted on the BSFO thin films to investigate how the Sm dopants affect the ferroelectric behavior of BSFO.In the present work, Bi0.85Sm0.15FeO3 (BSFO) was selected as the model system. The BSFO target was synthesized by a conventional solid-state sintering method using high-purity Bi2O3 (99.99%), Fe2O3 (99.95%) and Sm2O3 (99.90%) powders. Thin films were grown on (001) single-crystal SrTiO3 (STO) substrates epitaxially via PLD. KrF excimer laser with a wavelength of 248 nm was used as the laser source. Three different substrate temperatures, 600 °C, 640 °C and 670 °C, were applied in the deposition. For all depositions, oxygen partial pressure was kept at 200 mTorr and the deposition rate was 5 Hz. The films were cooled down to room temperature at a cooling rate of 10 °C min−1 in 200 torr oxygen atmospheres. The growth condition and parameters of BFO film is same with our previous report.24 Au top contacts with 100 nm thickness and 0.1 mm2 were deposited by a custom-built magnetron sputtering system. The Au sputter target (99.99% pure) is made by Williams Advanced Materials.X-ray diffraction (XRD) spectra were collected by a PANalytical Empyrean system using Cu Kα radiation. The Raman spectra were measured by Renishaw''s inVia Raman microscope. The microstructure analysis was performed on FEI TALOS F200X TEM/STEM operated at 200 kV. The energy-dispersive X-ray spectroscopy (EDS) chemical mapping was acquired by the SuperX EDS system with four silicon drift detectors. Ferroelectric characterization was conducted by Precision LC II Ferroelectric Tester (Radiant Technologies, Inc.). Fig. 1(a) shows the θ–2θ XRD spectra of the as-prepared thin film samples deposited at 600 °C, 640 °C and 670 °C. All the films display BSFO (00l) diffraction peaks, indicating highly textured BSFO along c-axis. It is noted that BSFO (003) peak shifts from 71.62°, to 70.82° and to 70.70° with the deposition temperature increasing from 600 °C to 640 °C, and 670 °C. The corresponding out-of-plane lattice parameters are calculated to be 3.951 Å, 3.987 Å and 3.993 Å, respectively and are summarized in Fig. 1(b). Compared with the out-of-plane lattice parameter of pure BFO film (∼4.000 Å) on STO substrate,24 three BSFO samples show smaller lattice parameters than that of pure BFO. This is because partial Bi3+ (radius = 1.030 Å) ions have been substituted by Sm3+ ions with smaller radius (radius = 0.958 Å).25 The BSFO peak at around 32.155° (denoted as “*”) in Fig. 1(a) comes from rhombohedral (110) peak and the peak disappears when the deposition temperature increases to 670 °C. The above results indicate that the deposition temperature influences the Sm-doping amount and the BSFO crystal structure. Raman analysis has been conducted on all BSFO and pure BFO films. The Raman spectra were fitted with Lorentzian curves, as shown in Fig. S1. The reported data of bulk polycrystalline Bi1−xSmxFeO3 was taken as reference.26 The overall shape of peaks is the same, which implies that the main structure of BSFO sample is the same as the rhombohedral R3c structure of BFO.Open in a separate windowFig. 1(a) θ–2θ XRD spectra of BSFO film deposited at 600 °C, 640 °C and 670 °C. (b) The summary of out-of-plane lattice parameter. (c–e) Reciprocal space map (RSM) results of BSFO (103) peaks.To further analyze the detailed phase information, asymmetric reciprocal space mapping (RSM) measurements were performed around the (103) diffraction peak for all the three BSFO samples and the results are shown in Fig. 1(c)–(e). The RSM pattern of sample (Tdep = 600 °C) exhibits four domains, which are shown by red triangles. It indicates the existence of rhombohedral-like phase which has antipolar nature.27–29 For the other two samples (Tdep = 670 °C and Tdep = 640 °C), peak split along Qx direction is not apparent and the narrower width along Qx direction is observed, indicating less structure distortion in BSFO films deposited at higher temperature. These results provide direct evidence that the deposition temperature significantly affects the domain structure of the BSFO film.In order to analyze the microstructure structure, TEM analysis has been applied on two samples (Tdep = 670 °C and Tdep = 600 °C). Fig. 2(a) and (c) show the overall films stacks of BSFO on STO substrates. The corresponding selected area electron diffraction (SAED) patterns of BSFO thin films only demonstrate the rhombohedral-like phases. It is interesting to note that the TEM image of high deposition temperature sample (Tdep = 670 °C) exhibits few dark lines. And the dark line density in the high deposition temperature sample is obviously higher than that in the lower deposition temperature one. The image contrast is proportional to ∼Z2 (Z, atomic number) in TEM bright-field mode. The dark line is therefore proposed be related with Sm, owing to ZSm is larger than ZBi and ZFe. It also suggests that the higher deposition temperature introduce more Sm dopants in BSFO films than the lower one. The Fig. 2(b) and (d) are high resolution TEM (HR-TEM) images from local areas, which were analyzed by Fast Fourier Transform (FFT). The spots (marked by red arrows) in the FFT image of the sample (Tdep = 670 °C) correspond to the incommensurate phase, which is caused by the competition between ferroelectric (FE) and antiferroelectric (AFE) phases. Different phase emerges in the sample (Tdep = 600 °C), and the corresponding spots are marked by red circle. It has been proved as the antipolar orthorhombic AFE phase, linked to the macroscopic AFE behavior. The phase information of Bi0.85Sm0.15FeO3 thin film in this study is different from previous reported BSFO with only AFE phases.16 The above microstructure analysis shows the effect of deposition temperature on the phase formation in BSFO system even with 15 atomic percent Sm.Open in a separate windowFig. 2(a and c) Cross-sectional TEM images of BSFO thin films (670 °C and 600 °C) on STO substrates. (b and d) High resolution TEM images. The insets in (a and c) show the corresponding (SAED) pattern of BSFO thin films. The insets in (b and d) show the fast-Fourier transformed (FFT) images from the blue squared region.STEM analysis was then performed to resolve the composition information. Fig. 3(a) shows the high-resolution STEM (HR-STEM) image of the 670 °C sample. The high angle annular dark field mode (HADDF) image intensity is proportional to the atomic number Z. Thus, the white line areas in STEM image correspond to the dark lines in TEM images. We further examined the composition distribution across this Sm layer using the intensity line profile (Fig. 3(b)), which provides a direct interpretation of composition information in the HAADF imaging mode. It is obvious that the position near white line area has higher intensity than other areas. This result proves that Sm3+ ion has been doped into BFO system effectively. Energy dispersive spectroscopy (EDS) measurements have been further applied on the same area. The EDS mapping of Bi and Sm elements are shown in Fig. S2(b) and (c). The EDS line-scan analysis of Sm is overlaid on the HADDF image and displayed in Fig. S2(a). The line profile reflects high content of Sm corresponding to the white line area. Therefore, both the TEM and STEM results show that the higher deposition temperature BSFO sample (Tdep = 670 °C) has higher Sm-doping amount.Open in a separate windowFig. 3(a) HR-STEM image of BSFO film deposited at 670 °C. (b) Enlarged view of the yellow dashed square area from (a). The intensity line profile is inserted along the marked blue line.The ferroelectric behaviors were characterized by the polarization–electric field (PE) hysteresis loops. Fig. 4(a)–(c) show the PE loops of BSFO samples with three different deposition temperatures, while Fig. 4(d) shows the loop of pure BFO as a comparison. The polarization measurement as a function of electric field measurement was carried out at room temperature for several times to ensure the reproducibility of the measurements. The BSFO sample (Tdep = 670 °C) with higher Sm-doping amount exhibits obvious enhanced polarization. The remnant polarization (Pr) for the film is determined to be 17 μC cm−2, much larger than other two BSFO samples and the BFO sample. It was proposed that the incorporation of Sm could break the short-range dipolar regions, surmount the local barrier and transform it to the long-range polar structure.30 The BFO film with four-variant domains exhibits a lower electric filed and remnant polarization Pr.31 It was also found that the formation of bridging phase could enhance piezoelectric and dielectric properties of BSFO.16 In this work, the BSFO sample (Tdep = 600 °C) shows four structural domain structure and the lowest Pr. With the increase amount of Sm-doping amount, incommensurate phase appears in the 670 °C sample. We conclude that the higher deposition temperature introduces the higher Sm-doping amount, which further assists the incommensurate phase formation and suppresses the AFE phase. In addition, the unsaturated PE loop of BFO film indicates it suffers from high leakage current, which is generally due to the appearance of Bi deficiencies and oxygen vacancies.32 The Sm–O bond enthalpy (565 ± 13 kJ mol−1) is stronger than the Bi–O bond enthalpy (337 ± 12.6 kJ mol−1).33 Therefore, the higher polarization exhibited by BSFO samples (Tdep = 670 °C) than the pure BFO proves that the Sm dopant could compensate for the Bi loss and suppress the formation of oxygen vacancies. The PE loop results were compared with prior reports on Re-BFO films. As shown in Table S1, the remnant polarization is quite different for Re-BFO systems. It is due to the different ionic radii of the rare earth elements, which result in different structural distortion of BFO and diverse critical doping ratio for phase transitions. Besides the phase variants, the polarization is closely related with the orientation of crystalline structures.Open in a separate windowFig. 4(a–c) Polarization hysteresis measurements for BSFO film deposited at 670 °C, 640 °C and 600 °C. (d) Polarization hysteresis measurements for BFO film.This study demonstrates that Sm-doping amount in BSFO thin films can be effectively tuned via deposition temperature. The Sm dopants influence phase formation of BSFO and further control the macroscopic ferroelectric properties. The local incommensurate phase presented by Bi0.85Sm0.15FeO3 with higher Sm-doping amount than the reported ones (Bi0.86Sm0.14FeO3), which is extremely helpful in constructing phase diagram of BSFO. More interestingly, the existence and location of Sm dopants in BSFO thin film have been directly demonstrated by the HR-STEM and corresponding EDS analysis. This work is also beneficial for the exploration of other Re-BFO films with deposition temperatures and detailed structure analysis, which is an important step toward the practical applications of Re-BFO in electronic devices.  相似文献   
9.
本研究对2013年1月~2018年5月期间在南华大学附属第一医院关节外科接受关节镜下半月板损伤修复的患者进行回顾性研究。结果示半月板损伤中:男女比例为0.71∶1;年龄(46.28±14.55)岁; 不同膝关节半月板损伤类型占比中混合裂>联合损伤>放射裂>水平裂>纵裂>桶柄裂>单纯退行性变;单纯半月板撕裂内外比例(内侧半月板损伤∶外侧半月板损伤)为0.74∶1;联合损伤发生最多的是内侧后角联合外侧前角,约占总联合损伤的33.57%,远高于其他损伤类型;内侧半月板后角较其他部位损伤更易出现联合对侧半月板损伤,该研究揭示了半月板损伤分布特点,为易患人群的疾病预防提供了理论基础。  相似文献   
10.
浅谈表证     
谢君成  曾纪斌 《中医学报》2020,35(8):1660-1663
外邪侵袭机体,太阳首当其冲。太阳表证分为太阳中风证和太阳伤寒证。太阳中风证,常以桂枝汤调和营卫、祛风解肌;太阳伤寒证则以麻黄汤祛风散寒。阳明表证有汗出,则治以桂枝汤;无汗而喘,则治以麻黄汤。少阳表证包括少阳中风证和少阳伤寒证,常以小柴胡汤解肌透邪。太阴亦有表证,桂枝汤为治疗太阴表证的主方。少阴病多以里虚证为主,但亦有表证,常以麻黄细辛附子汤、麻黄附子甘草汤扶阳解表。厥阴为六经之最里,亦有表证,包括厥阴中风和厥阴伤寒,常以当归四逆汤、吴茱萸汤温经散寒。  相似文献   
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