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   482篇
  免费   21篇
  国内免费   4篇
耳鼻咽喉   17篇
儿科学   2篇
妇产科学   85篇
基础医学   35篇
口腔科学   15篇
临床医学   37篇
内科学   87篇
皮肤病学   6篇
神经病学   12篇
特种医学   7篇
外科学   101篇
综合类   6篇
预防医学   28篇
眼科学   3篇
药学   53篇
中国医学   1篇
肿瘤学   12篇
  2024年   1篇
  2023年   5篇
  2022年   9篇
  2021年   22篇
  2020年   9篇
  2019年   13篇
  2018年   23篇
  2017年   5篇
  2016年   15篇
  2015年   16篇
  2014年   16篇
  2013年   25篇
  2012年   21篇
  2011年   32篇
  2010年   26篇
  2009年   22篇
  2008年   27篇
  2007年   32篇
  2006年   32篇
  2005年   29篇
  2004年   28篇
  2003年   24篇
  2002年   23篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1983年   1篇
  1982年   3篇
  1981年   4篇
  1980年   1篇
  1979年   7篇
  1978年   6篇
  1977年   3篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
排序方式: 共有507条查询结果,搜索用时 15 毫秒
101.
This study aims to estimate the proportion of significant mesosalpingeal adipose tissue condensation (lipomesosalpinx, at least of a caliber similar to the ampulla of the ipsilateral tube regardless of well-defined or poorly defined margins) among infertile women subjected to diagnostic laparoscopy. This study is a cross-sectional study set at a specialized endoscopic center. All infertile women scheduled for diagnostic/therapeutic laparoscopy during the period between July 1994 and December 2012 was included in this study. Interventions used were preoperative hysterosalpingography, transvaginal ultrasonography, as well as body mass index for all cases. Laparoscopic documentation of a significant mesosalpingeal condensation of adipose tissue as well as histopathologic assessment of the adipose tissues in some cases was observed. The main outcome measures included number of cases with unilateral or bilateral lipomesosalpinx. Significant lipomesosalpinx was diagnosed in 145 (5.7 %) out of 2,563 cases examined by laparoscopy. In all but seven cases, lipomesosalpinx was seen bilaterally (99.7 %). There was insignificant correlation between those cases and high body mass index when compared to the rest of the cases. Infertility was unexplained by laparoscopy in 621 cases (24.3 %) while laparoscopy diagnosed etiologic factors in 1,942 (75.7 %) cases. Lipomesosalpinx was seen in 46 (7.4 %) and 79 (3.9 %) of the unexplained and explained cases, respectively, without a statistically significant difference (P?=?0.48). Despite being a rare laparoscopic finding, significant lipomesosalpinx should be reported and documented as a possible missed tubal factor of infertility. Whether to treat lipomesosalpinx or not, bilaterally or unilaterally and by which means, require further studies with proper second-look laparoscopy.  相似文献   
102.
AIM To detect risk factors for post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP) and investigate the predictors of its severity.METHODS This is a prospective cohort study of all patients who underwent ERCP.Pre-ERCP data,intraoperative data,and post-ERCP data were collected.RESULTS The study population consisted of 996 patients.Their mean age at presentation was 58.42(± 14.72) years,and there were 454 male and 442 female patients.Overall,PEP occurred in 102(10.2%) patients of the study population; eighty(78.4%) cases were of mild to moderate degree,while severe pancreatitis occurred in 22(21.6%) patients.No hospital mortality was reported for any of PEP patients during the study duration.Age less than 35 years(P = 0.001,OR = 0.035),narrower common bile duct(CBD) diameter(P = 0.0001) and increased number of pancreatic cannulations(P = 0.0001) were independent risk factors for the occurrence of PEP.CONCLUSION PEP is the most frequent and devastating complication after ERCP.Age less than 35 years,narrower median CBD diameter and increased number of pancreaticcannulations are independent risk factors for the occurrence of PEP.Patients with these risk factors are candidates for prophylactic and preventive measures against PEP.  相似文献   
103.
104.
BACKGROUND: The aim of this study was to determine if the number of treatment sessions has an influence on the final intermediate term results of submucosal bipolar radiofrequency volumetric tissue reduction of the inferior turbinate. METHODS: One hundred two patients were enrolled in this study prospectively. The procedure was done using the Coblation (Arthrocare Corp., Sunnyvale, CA). The assessment was done using the 10-cm visual analog scale and acoustic rhinometry. Surgical procedures and pre- and postoperative assessments were done at the Faculty of Medicine, Cairo University. RESULTS: Eighty eight percent of our study population achieved final relief of their nasal obstruction, and at least three sessions were needed to maintain the favorable outcome at 1-year follow up. CONCLUSION: Increasing the number of bipolar radiofrequency volumetric tissue reduction treatment sessions was associated with better intermediate-term outcome. This was confirmed using subjective and objective methodology.  相似文献   
105.

Aim of work

Robotics in surgery led to an improvement of visualization, a better handling of tissues and better suturing. This study aimed to document the first experience of the Egyptian National Cancer Institute (NCI) using the robot-assisted laparoscopic approach in radical hysterectomies for cervical cancer and to highlight observed advantages, disadvantages, morbidity and oncological outcomes.

Patients and methods

Data of cases that had either early cervical cancer (stage IB-IIA1 with a tumor ≥2?cm) or locally advanced cervical cancer (Stage IIA2-IIB after chemo-radiotherapy) were collected prospectively. Study patients underwent robotic radical hysterectomies for their cervical cancers at the NCI, Cairo University, between January 1, 2015 and December 31, 2016. For each patient, duration of surgery, amount of blood loss, and intra-operative complications were recorded. Similarly, the duration of postoperative hospital-stay, analgesia used and post-operative gastrointestinal recovery were documented. Pathological assessment of safety margins and the lymph nodes number yield were also assessed.

Results

Twenty patients underwent robotic radical hysterectomy during the study period. Twelve cases had early cervical cancer while 8 suffered locally advanced disease. The mean procedure time was 319 (range 240–560) minutes; the mean blood loss was 309 (range 150–600) ml. Three cases had bladder injuries during their procedures. The median hospital stay was 6 (range 4–10) days. One case had a positive margin. The median of lymph nodes yield number was 15 (range 10–25). Follow-up ranged 9–31?months, with only one case developing local recurrence.

Conclusion

Robotic radical hysterectomy is a feasible approach with a tolerable rate of complications.  相似文献   
106.
The synthesis of nanoparticles by green approaches is gaining unique importance due to its low cost, biocompatibility, high productivity, and purity, and being environmentally friendly. Herein, biomass filtrate of Pseudomonas aeruginosa isolated from mangrove rhizosphere sediment was used for the biosynthesis of zinc oxide nanoparticles (ZnO-NPs). The bacterial isolate was identified based on morphological, physiological, and 16S rRNA. The bio-fabricated ZnO-NPs were characterized using color change, UV-visible spectroscopy, FT-IR, TEM, and XRD analyses. In the current study, spherical and crystalline nature ZnO-NPs were successfully formed at a maximum SPR (surface plasmon resonance) of 380 nm. The bioactivities of fabricated ZnO-NPs including antibacterial, anti-candida, and larvicidal efficacy were investigated. Data analysis showed that these bioactivities were concentration-dependent. The green-synthesized ZnO-NPs exhibited high efficacy against pathogenic Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and unicellular fungi (Candida albicans) with inhibition zones of (12.33 ± 0.9 and 29.3 ± 0.3 mm), (19.3 ± 0.3 and 11.7 ± 0.3 mm), and (22.3 ± 0.3 mm), respectively, at 200 ppm. The MIC value was detected as 50 ppm for E. coli, B. subtilis, and C. albicans, and 200 ppm for S. aureus and P. aeruginosa with zones of inhibition ranging between 11.7 ± 0.3–14.6 ± 0.6 mm. Moreover, the biosynthesized ZnO-NPs showed high mortality for Culex pipiens with percentages of 100 ± 0.0% at 200 ppm after 24 h as compared with zinc acetate (44.3 ± 3.3%) at the same concentration and the same time.  相似文献   
107.
Objective: A cervicovaginal fetal fibronectin value of ≥50 ng/mL has been used to define women at risk of having a preterm birth. We evaluated the relationship between quantitative fetal fibronectin values and spontaneous preterm birth. Study Design: Cervical and vaginal specimens for fetal fibronectin were obtained at 24, 26, 28, and 30 weeks’ gestation from 2926 women. Quantitative fetal fibronectin values were calculated by using absorbances determined by enzyme-linked immunosorbent assay. The highest fetal fibronectin value (cervical or vaginal) for each woman at each visit was evaluated in relation to spontaneous preterm birth at <35 weeks’ gestation. Receiver operating characteristic curves were constructed to determine the optimal cutoff point for fetal fibronectin values to predict spontaneous preterm birth at <35 weeks’ gestation and within 4 weeks of testing. Results: The risk of spontaneous preterm birth increased as a function of increasing fetal fibronectin values from approximately 20 to 300 ng/mL. Fetal fibronectin values ≥300 ng/mL were not associated with a further increase in spontaneous preterm birth. Examination of the receiver operating characteristic curve indicates that the optimal cutoff point for a positive fetal fibronectin test result at 24 to 30 weeks’ gestation to predict spontaneous preterm birth at <35 weeks is between 45 and 60 ng/mL. Conclusion: Increasing levels of cervicovaginal fetal fibronectin up to 300 ng/mL are associated with an increasing risk of spontaneous preterm birth. Nevertheless, at 24 to 30 weeks, the value currently used, 50 ng of fetal fibronectin per milliliter, appears to be a reasonable cutoff point for predicting spontaneous preterm birth at <35 weeks’ gestation. (Am J Obstet Gynecol 2000;183:1480-3.)  相似文献   
108.
Intracellular thermostable esterase produced by the extremophilic Geodermatophilus obscurus G20 was purified to homogeneity by a heat treatment, followed by an anion‐exchange chromatography, and then characterized. The molecular weight of the purified enzyme determined by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) was shown to be approximatively 55 kDa. The enzyme showed an optimal activity between pH 8.0 and 9.0 and was stable in the pH range 7.0–10.0. Moreover, it is highly thermostable, with a residual activity greater than 90% after incubation at 80 °C for more than 10 h. The enzyme showed preference for esters of p ‐nitrophenol with short chain fatty acid. When the p ‐nitrophenyl acetate (C2) was used as substrate, the Michaelis–Menten constant (Km) and maximum velocity for the reaction (Vmax) of esterase were 400 μM and 2500 U/mg protein, respectively. The effect of phenylmethanesulphonyl fluoride (PMSF), a serine‐specific inhibitor, on the enzyme activity suggested that the thermostable esterase belong to the serine hydrolase group. Because of its high thermostability, activity at alkaline pH, tolerance to methanol and various metal ions and specificity for short chain fatty acids, this enzyme showed high potential for use in biocatalysis. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
109.
Hypertension (HTN) is a chronic condition of concern due to its role in the causation of coronary artery disease (CAD), stroke, and other vascular complications. Essential hypertension (EH) is a multifactorial disorder arising from the influence of several susceptibility genes and environmental stimuli. Apolipoprotein E (Apo E) plays an essential role in clearance of chylomicron remnants and very low-density lipoproteins (VLDL). Apo E gene has three alleles (E2, E3, and E4) that give rise to six different genotypes. A significant association of E4 allele has been observed with HTN in addition to the other well-known risk factors and positive family history. Carriers of E4 allele form a higher risk group showing greater susceptibility to CAD. These observations emphasize the need of genotyping Apo E in patients with EH as an important molecular tool in personalized medicine. The aim of this work was to study the association between Apo E gene polymorphism and EH in Egyptian patients as well as correlating different Apo E genotypes with serum lipids. The study was conducted on 50 patients with EH and 50 age-matched controls. DNA analysis was performed using polymerase chain reaction restriction fragment length polymorphism. The E3/E3 genotype was found in 85.42 % of patients, compared to 80 % in controls. E3/E4 (8.33 %) and E2/E3 (6.25 %) were lower in patients compared to controls 12 and 8 %, respectively. E4/E4 and E2/E2 genotypes were only found in two patients (4 %). Total cholesterol and low-density lipoprotein were significantly higher in E3/E4 as compared to E3/E3 and E2/E3. However, there was no significant difference in triglyceride, high-density lipoprotein, and VLDL.  相似文献   
110.

Introduction

Adipose tissue can release hormones into the blood stream in response to specific extracellular stimuli or changes in metabolic status. Resistin, an adipose-secreted factor, is primarily involved in the modulation of insulin sensitivity and adipocyte differentiation. Adiponectin, an adipocyte-specific hormone with insulin sensitizing, anti-inflammatory and anti-atherogenic effects, is reduced in obesity and type II diabetes. The aim of the study was to assess the influence of maternal pre-existing diabetes on cord blood resistin and adiponectin at birth in relation to neonatal anthropometric parameters and cord blood insulin levels.

Material and methods

A total of 60 term newborns were prospectively enrolled and categorized into three groups: 20 were macrosomic infants of pre-gestational diabetic mothers (group I), 20 were non-macrosomic infants of pre-gestational diabetic mothers (group II) and 20 were healthy non-macrosomic infants born to non-diabetic mothers serving as controls (group III). Infants’ anthropometric indices were recorded. Cord blood samples for glucose, insulin, resistin and adiponectin assay, together with maternal glycosylated haemoglobin were obtained.

Results

Serum insulin was increased while resistin and adiponectin were significantly decreased in infants of diabetic mothers (IDMs) compared to the control group. Serum glucose, insulin, resistin and adiponectin were comparable in group I and II. Cord serum resistin correlated positively with cord blood glucose in IDMs in both macrosomic and non-macrosomic groups. Cord serum insulin correlated positively with triceps skinfold thickness in all studied neonates. Cord serum resistin and adiponectin showed no correlation with neonatal anthropometric indices. Multiple regression analysis demonstrated that insulin, resistin and adiponectin together were highly correlated with birth weight, with adiponectin as the one responsible for this positive correlation.

Conclusions

Infants of diabetic mothers had elevated levels of cord serum insulin and suppressed levels of cord serum resistin and adiponectin, suggesting that the regulation of these metabolic pathways is probably operational before birth. Levels were comparable in both macrosomic and non-macrosomic neonates.  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