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   413篇
  免费   25篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   9篇
妇产科学   16篇
基础医学   62篇
口腔科学   59篇
临床医学   46篇
内科学   42篇
皮肤病学   4篇
神经病学   52篇
特种医学   10篇
外科学   19篇
综合类   6篇
预防医学   47篇
眼科学   1篇
药学   18篇
肿瘤学   44篇
  2023年   2篇
  2022年   8篇
  2021年   4篇
  2020年   4篇
  2019年   4篇
  2018年   5篇
  2017年   6篇
  2016年   8篇
  2015年   9篇
  2014年   11篇
  2013年   15篇
  2012年   37篇
  2011年   26篇
  2010年   9篇
  2009年   22篇
  2008年   30篇
  2007年   32篇
  2006年   24篇
  2005年   25篇
  2004年   22篇
  2003年   28篇
  2002年   30篇
  2001年   3篇
  2000年   5篇
  1999年   7篇
  1998年   9篇
  1997年   4篇
  1996年   4篇
  1995年   5篇
  1994年   4篇
  1993年   4篇
  1992年   2篇
  1991年   6篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1982年   2篇
  1981年   2篇
  1979年   1篇
  1977年   2篇
  1974年   1篇
  1973年   4篇
  1969年   1篇
  1965年   1篇
  1963年   1篇
  1961年   1篇
  1958年   1篇
  1956年   1篇
排序方式: 共有439条查询结果,搜索用时 31 毫秒
1.
Zusammenfassung Bei 10 Patientinnen mit puerperaler Mastitis wurde der Absze? durch wiederholte Punktion, kombiniert nit einer systemischen Antibiotikagabe behandelt. Bei 1 Patientin wurde eine infizierte Milchzyste drainiert. Mit 3–6 Punktionen und einer Therapiedauer von 7–10 Tagen ist der therapeutische Aufwand dieser Methode deutlich geringer als beim Standardverfahren Inzision und Drainage (3–4 Wochen). Die Mütter k?nnen weiterstillen.  相似文献   
2.
OBJECTIVE: The aim of this study was to test the effectiveness of a newly developed system, using masking noises with specific frequencies and amplitudes, adjusted to typical noises experienced during dental treatment such as the high-speed hand-held drill. METHOD AND MATERIALS: In accordance with an analysis of typical noises experienced during dental treatment, masking noises with specific frequencies (frequency range 0.02 to 20 kHz) and amplitudes were created, with the aim of reducing the patients' awareness of typical treatment noises by overlaying frequencies. Two hundred fifty-four outpatients (113 males, 141 females) with a mean age of 32 years (+/- 10.5 years) were enrolled in this study. Patients were treated 15 minutes with and 15 minutes without the masking noise. Patients and practitioners filled out questionnaires aimed to evaluate the effectiveness of the system, sensitivity to noise (scale 0 to 10; 0 = effective, 10 = noneffective), psychologic aspects, and statements of fear. RESULTS: There was a significant reduction in patients' awareness of noise using this system during dental treatment. Most of the patients regarded the masking noise as a pleasureable supplementation to common treatment and would select this manner of dental treatment employing the device again (81.5%); 48.2% said they were more relaxed. The system does not, in principle, interfere with dental treatment, and in most instances, the device does not impede the communication between practitioners and patients. CONCLUSION: The present study demonstrates that using masking noises during dental treatment reduces the sensitivity to drill noise, reduces fear and stress, and may be useful in dental practice as an adjunct to common dental treatment.  相似文献   
3.
Summary The thymus develops from a paired epithelial anlage in the neck. This review considers how ectoderm (vesicula cervicalis) and endoderm (third pharyngeal pouch) contribute to the epithelial stroma of the thymus. Stromal elements of mesodermal origin are capillaries, septae and perivascular spaces and single invading cells. These elements separate the thymus into pseudolobuli. The thymus epithelial space and the perivascular spaces are always separated from each other by a closed, flat epithelial cell layer, with a basal lamina which contributes to the blood-thymus barrier. From the 9th gestational week, prethymic precursor cells from hemopoietic centers, begin to invade the thymus anlage. There they finally mature to committed post-thymic T cells. The thymus microenvironment of postnatal thymus is composed of six different types of epithelial cells and several stromal cells of mesodermal origin. The location of these diverse stationary cells is described, and their functional significance is discussed. Obviously these stromal cell types have a special function in providing the proper environment for T-cell maturation. The function of the thymus includes the maturation and/or selection of antigen specific T-cells. The main issue of intra-thymic T-cell differentiation is the development and expression of T-cell-antigen receptors. The great diversity of these receptors is generated by a rearrangement of the T-cell-receptor-genes in order to furnish the host with a mature T-cell repertoire that is capable of recognizing the world of extrinsic antigens. In a synopsis the manyfold interrelationships between the thymus microenvironment and the developing thymocytes are summarised.Abbreviations BALT Bronchus Associated Lymphoid Tissue - CD Cluster of Differentiation - cCD3 cytoplasmic CD3 - mCD3 membranous CD3 - C.R. Crown Rump - GALT Gut Associated Lymphoid Tissue - HLA Human Leucocyte antigen - HLA-DR Gene product of the MHC-class II (this antigen is a surface molecule of numerous stationary and free cells of the immune system) - IDC Interdigitating Cell - IL1 Interleukin 1 (cytokine derived mainly from makrophages, but also from other cell types) - IL2 and IL4 Interleukin 2 and 4 (cytokines derived mainly from T-cell, but also from other cell types) - IL4R Interleukin 4-Receptor - Mab Monoclonal antibody - MHC Major Histocompatibility Complex - p.c. post conception - TCR T-Cell-Receptor - TNC Thymic Nurse Cell - TdT Terminal deoxynucleotidyl Transferase  相似文献   
4.
5.
6.
Abstract: Background: Fetal movement counting may improve timely identification of decreased fetal activity and thereby contribute to prevent adverse pregnancy outcomes, but it may also contribute to maternal concern. This study aimed to test whether fetal movement counting increased maternal concern. Methods: In a multicenter, controlled trial 1,013 women with a singleton pregnancy were randomly assigned either to perform daily fetal movement counting from pregnancy week 28 or to follow standard Norwegian antenatal care where fetal movement counting is not encouraged. The primary outcome was maternal concern, measured by the Cambridge Worry Scale. Analysis was by intention-to-treat. Results: The means and SDs on Cambridge Worry Scale scores were 0.77 (0.55) and 0.90 (0.62) for the intervention and the control groups, respectively, a mean difference between the groups of 0.14 (95% CI: 0.06–0.21, p < 0.001). Decreased fetal activity was of concern to 433 women once or more during pregnancy, 45 and 42 percent in the intervention and control groups, respectively (relative risk = 1.1, 95% CI: 0.9–1.2). Seventy-nine percent of the women responded favorably to the use of counting charts. Conclusions: Women who performed fetal movement counting in the third trimester reported less concern than those in the control group. The frequency of maternal report of concern about decreased fetal activity was similar between the groups. Most women considered the use of a counting chart to be positive. (BIRTH 39:1 March 2012)  相似文献   
7.
Extant crocodilians are a highly apomorphic archosaur clade that is ectothermic, yet often achieve large body sizes that can be subject to higher heat loads. Therefore, the anatomical and physiological roles that blood vessels play in crocodilian thermoregulation need further investigation to better understand how crocodilians establish and maintain cephalic temperatures and regulate neurosensory tissue temperatures during basking and normal activities. The cephalic vascular anatomy of extant crocodilians, particularly American alligator (Alligator mississippiensis) was investigated using a differential‐contrast, dual‐vascular injection technique and high resolution X‐ray micro‐computed tomography (μCT). Blood vessels were digitally isolated to create representations of vascular pathways. The specimens were then dissected to confirm CT results. Sites of thermal exchange, consisting of the oral, nasal, and orbital regions, were given special attention due to their role in evaporative cooling and cephalic thermoregulation in other diapsids. Blood vessels to and from sites of thermal exchange were studied to detect conserved vascular patterns and to assess their ability to deliver cooled blood to neurosensory tissues. Within the orbital region, both the arteries and veins demonstrated consistent branching patterns, with the supraorbital, infraorbital, and ophthalmotemporal vessels supplying and draining the orbit. The venous drainage of the orbital region showed connections to the dural sinuses via the orbital veins and cavernous sinus. The palatal region demonstrated a vast plexus that comprised both arteries and veins. The most direct route of venous drainage of the palatal plexus was through the palatomaxillary veins, essentially bypassing neurosensory tissues. Anastomotic connections with the nasal region, however, may provide an alternative route for palatal venous blood to reach neurosensory tissues. The nasal region in crocodilians is probably the most prominent site of thermal exchange, as it offers a substantial surface area and is completely surrounded by blood vessels. The venous drainage routes from the nasal region offer routes directly to the dural venous sinuses and the orbit, offering evidence of the potential to directly affect neurosensory tissue temperatures. The evolutionary history of crocodilians is complex, with large‐bodied, terrestrial, and possibly endothermic taxa that may have had to deal with thermal loads that likely provided the anatomical building‐blocks for such an extensive vascularization of sites of thermal exchange. A clear understanding of the physiological abilities and the role of blood vessels in the thermoregulation of crocodilians neurosensory tissues is not available but vascular anatomical patterns of crocodilian sites of thermal exchange indicate possible physiological abilities that may be more sophisticated than in other extant diapsids.  相似文献   
8.
Tobacco smoking is a risk factor for atrial fibrillation (AF), but little is known about the impact of smoking in patients with AF. Of the 4060 patients with recurrent AF in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, 496 (12%) reported having smoked during the past two years. Propensity scores for smoking were estimated for each of the 4060 patients using a multivariable logistic regression model and were used to assemble a matched cohort of 487 pairs of smokers and nonsmokers, who were balanced on 46 baseline characteristics. Cox and logistic regression models were used to estimate the associations of smoking with all-cause mortality and all-cause hospitalization, respectively, during over 5 years of follow-up. Matched participants had a mean age of 70 ± 9 years (± S.D.), 39% were women, and 11% were non-white. All-cause mortality occurred in 21% and 16% of matched smokers and nonsmokers, respectively (when smokers were compared with nonsmokers, hazard ratio=HR=1.35; 95% confidence interval=95%CI=1.01-1.81; p=0.046). Unadjusted, multivariable-adjusted and propensity-adjusted HR (95% CI) for all-cause mortality associated with smoking in the pre-match cohort were: 1.40 (1.13-1.72; p=0.002), 1.45 (1.16-1.81; p=0.001), and 1.39 (1.12-1.74; p=0.003), respectively. Smoking had no association with all-cause hospitalization (when smokers were compared with nonsmokers, odds ratio=OR=1.21; 95%CI=0.94-1.57, p=0.146). Among patients with AF, a recent history of smoking was associated with an increased risk of all-cause mortality, but had no association with all-cause hospitalization.  相似文献   
9.
The addition of epinephrine in dental local anaesthesia results in a longer and deeper anaesthesia under almost ischemic conditions. For short-time dental treatments, epinephrine-reduced anaesthetics may offer shorter and more individual anaesthesia with reduced potential side effects. The aim of this study was a clinical evaluation of anaesthetic potency and adverse effects of an epinephrine-reduced articaine formulation in dental patients undergoing short-time routine treatment. In a prospective clinical, not interventional, study between January 2008 and February 2009, 908 patients undergoing short-time dental treatment in five medical centers were anaesthetized with 4% articaine 1:400,000 epinephrine (Ubistesin, 3M/ESPE, Seefeld, Germany). Efficacy and safety in clinical use were evaluated. A follow-up after 1 day was conducted by telephone survey. A mean amount of 1.3-ml anaesthetic solution was needed to achieve a complete or sufficient anaesthesia in 97% (n = 876) of cases. A second injection had to be done in 3.7% (n = 34) before and in 11.9% (n = 108) during treatment. Here, the second injection had to be applied after a mean of 48.6 min. The mean duration of soft tissue anaesthesia after infiltration was 146.6 min, after nerve block 187.7 min. The painful treatment took a mean of 50.2 min and the total treatment time summed up to 68.8 min. In 1.7% cases (n = 15), unwanted side effects were observed. The results indicate that a lower concentration of epinephrine in combination with the 4% articaine solution leads to a high success rate of efficacy. The clinical use of a 4% articaine 1:400,000 epinephrine solution can be stated as safe and effective in short dental routine treatments. Reconsiderations concerning limitations of indication or additional contraindications are not necessary.  相似文献   
10.
The aim of the present study was to investigate the association between caries frequency and body mass index (BMI) in German elementary school children. A total of 1,290 elementary school children (648 boys, 642 girls) were examined. The dental examination included the determination of caries frequency (DF-T/df-t values). The medical evaluation assessed the pupils’ general health and BMI. The study showed that 3.6% of the children were underweight, 74.8% had a normal weight, 11.9% were overweight, and 9.7% were obese. Underweight children showed natural healthy teeth in 44.7%, those with normal weight in 40.7%, whereas children with high weight and obese children showed natural healthy teeth in 30.5% and 31.7%, respectively. A significant association between high weight and caries frequency in the first dentition (p = 0.0067) and in the permanent dentition (p = 0.0002) could be observed. The association remains statistically significant after adjusting for age. The number of natural healthy teeth decreased with age (p = 0.001) and BMI (p = 0.0061) and was different between girls and boys (p = 0.0334). This study demonstrated a significant association between caries frequency and weight in school children. In future preventive programs, the importance of nutrition should not only be emphasized with respect to general diseases but also with regard to carious lesions.  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