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81.
82.

Objective

The objectives of this project were to: 1) develop strong and durable dental resin composites by employing new monomers that are hydrolytically stable, and 2) demonstrate that resin composites based on these monomers perform superiorly to the traditional bisphenol A glycidyl dimethacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) composites under testing conditions relevant to clinical applications.

Methods

New resins comprising hydrolytically stable, ether-based monomer, i.e., triethylene glycol divinylbenzyl ether (TEG-DVBE), and urethane dimethacrylate (UDMA) were produced via composition-controlled photo-polymerization. Their composites contained 67.5 wt% of micro and 7.5 wt% of nano-sized filler. The performances of both copolymers and composites were evaluated by a battery of clinically-relevant assessments: degree of vinyl conversion (DC: FTIR and NIR spectroscopy); refractive index (n: optical microscopy); elastic modulus (E), flexural strength (F) and fracture toughness (KIC) (universal mechanical testing); Knoop hardness (HK; indentation); water sorption (Wsp) and solubility (Wsu) (gravimetry); polymerization shrinkage (Sv; mercury dilatometry) and polymerization stress (tensometer). The experimental UDMA/TEG-DVBE composites were compared with the Bis-GMA/TEGDMA composites containing the identical filler contents, and with the commercial micro hybrid flowable composite.

Results

UDMA/TEG-DBVE composites exhibited n, E, Wsp, Wsu and Sv equivalent to the controls. They outperformed the controls with respect to F (up to 26.8% increase), KIC (up to 27.7% increase), modulus recovery upon water sorption (full recovery vs. 91.9% recovery), and stress formation (up to 52.7% reduction). In addition, new composites showed up to 27.7% increase in attainable DC compared to the traditional composites. Bis-GMA/TEGDMA controls exceeded the experimental composites with respect to only one property, the composite hardness. Significantly, up to 18.1% lower HK values in the experimental series (0.458 GPa) were still above the clinically required threshold of approx. 0.4 GPa.

Significance

Hydrolytic stability, composition-controlled polymerization and the overall enhancement in clinically-relevant properties of the new resin composites make them viable candidates to replace traditional resin composites as a new generation of strong and durable dental restoratives.  相似文献   
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85.
We studied paraphenylenediamine (PPD)-related acute kidney injury (AKI) in 81 patients and also in albino rats experimentally. In the patients' group AKI was found in 32.7%. Of them, 81.4% needed dialysis support. The overall mortality was 25.9%. In experimental rats the renal lesions were noted in all and they were glomerular congestion, intertubular (interstitial) hemorrhages, acute tubular necrosis, mesangial proliferation, and intratubular casts. The severity of renal injury appears to be dose dependent.  相似文献   
86.
The human estrogenic enzyme 17beta-hydroxysteroid dehydrogenase type-1 (HSD17B1) provides biosynthesis regulation of active estrogen in stimulating the development of breast cancer through cell proliferation. The β-sitosterol is classified as a steroid compound and is actually a type of triterpenoid compound that has a similar structure to a steroid. This similarity provides a great opportunity for the inhibitor candidate to bind to the HDS17B1 enzyme because of the template similarity on the active site. Several in silico approaches have been applied in this study to examine the potential of these two inhibitor candidates. Pharmacokinetic studies showed positive results by meeting several drug candidate criteria, such as drug-likeness, bioavailability, and ADMET properties. A combination of molecular docking and MD simulation showed good conformational interaction of the inhibitors and HSD17B1. Prediction of binding free energy (ΔGbind) using the Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) approach shows ΔGbind (kcal mol−1) of C1–HSD17B1: −49.31 ± 0.23 and C2–HSD17B1: −33.54 ± 0.34. Meanwhile, decomposition energy analysis (ΔGresiduebind) suggested several key residues that were also responsible for the interaction with inhibitors, such as C1–HSD17B1 (six residues: Leu96, Leu149, Pro187, Met193, Val225, and Phe226) and C2–HSD17B1 (four residues: Ile14, Gly94, Pro187, and Val188). Hopefully, the obtained results from this research could be considered for the mechanistic inhibition of the HSDS17B1 enzyme at molecular and atomistic levels.

We presented pharmacokinetic study, molecular docking, and MD simulation to study β-sitosterol and oleanolic acid compounds and potential HSD17B1 inhibitors.  相似文献   
87.
Histiocytosis-X is a rare disease. It occurs mostly in children. Aetiology is unknown. Treatment is by surgery, Radiotherapy and Chemotherapy, either singly or in combination. Prognosis depends on the degree of involvement. One such case is reported and discussed.  相似文献   
88.
Dengue Encephalopathy   总被引:3,自引:0,他引:3  
Dengue encephalopathy or dengue hemorrhagic fever (DHF) with CNS involvement used to be considered a relatively rare condition; but the number of cases reported in human studies has been increasing every year. Diagnosis of dengue encephalopathy is based on clinically diagnosed DHF according to the W.H.O. criteria (1980), with CNS manifestations consisting of abrupt onset of hyperpyrexia, nontransient alteration of consciousness, headache, vomiting-with or without seizures -and normal CSF. Many factors may be considered to be directly or indirectly associated with CNS signs and symptoms in DHF, the main pathology being leakage of plasma into serous spaces and abnormal hemostasis, leading to hypovolemic shock and hemorrhage in many organs of the body. Acute liver failure is considered to be one of the main factors causing brain pathology. One hundred fifty-two cases of dengue encephalopathy admitted during 3 periods at the Cipto Mangunkusumo Hospital in Jakarta were studied retrospectively. The overall incidence was 152 out of 2,441 DHF cases, or 6.2%. The most pronounced symptoms were hyperpyrexia, alteration of consciousness and convulsions. Laboratory examination showed an unusually high increase of serum transaminases, hyponatremia, and hypoxia. Neurologic abnormalities detected were hemiparesis and tetraparesis of the extremities, and second nerve atrophy; such abnormalities were found in 10 out of the 152 cases, or 6.5%.  相似文献   
89.
PURPOSE: A classic twin study was undertaken to assess the contribution of genes and environment to the development of refractive errors and ocular biometrics in a twin population. METHODS: A total of 1224 twins (345 monozygotic [MZ] and 267 dizygotic [DZ] twin pairs) aged between 18 and 88 years were examined. All twins completed a questionnaire consisting of a medical history, education, and zygosity. Objective refraction was measured in all twins, and biometric measurements were obtained using partial coherence interferometry. RESULTS: Intrapair correlations for spherical equivalent and ocular biometrics were significantly higher in the MZ than in the DZ twin pairs (P < 0.05), when refraction was considered as a continuous variable. A significant gender difference in the variation of spherical equivalent and ocular biometrics was found (P < 0.05). A genetic model specifying an additive, dominant, and unique environmental factor that was sex limited was the best fit for all measured variables. Heritability of spherical equivalents of 88% and 75% were found in the men and women, respectively, whereas, that of axial length was 94% and 92%, respectively. Additive genetic effects accounted for a greater proportion of the variance in spherical equivalent, whereas the variance in ocular biometrics, particularly axial length was explained mostly by dominant genetic effects. CONCLUSIONS: Genetic factors, both additive and dominant, play a significant role in refractive error (myopia and hypermetropia) as well as in ocular biometrics, particularly axial length. The sex limitation ADE model (additive genetic, nonadditive genetic, and environmental components) provided the best-fit genetic model for all parameters.  相似文献   
90.
Thyagarajan S  Mearza AA  Falcon MG 《Cornea》2006,25(6):748-749
PURPOSE: To present a case of inadvertently retained Descemet Membrane (DM). METHODS: Case report. RESULTS: A 41-year-old male with previous history of retinal detachment surgery underwent a repeat penetrating keratoplasty; the first graft decompensated secondary to silicone oil. Postoperatively, an inadvertently retained DM was observed forming a physical barrier to the silicone oil. CONCLUSION: Retained DM is a rare complication of penetrating keratoplasty, with only a few cases reported in the literature. This membrane served a protective role from the effects of silicone oil on the donor cornea but later opacified and required surgical intervention.  相似文献   
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