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   235篇
  免费   17篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   9篇
基础医学   30篇
口腔科学   6篇
临床医学   22篇
内科学   74篇
神经病学   8篇
特种医学   9篇
外科学   26篇
预防医学   12篇
眼科学   2篇
药学   7篇
肿瘤学   35篇
  2023年   2篇
  2022年   5篇
  2021年   8篇
  2020年   6篇
  2019年   7篇
  2018年   6篇
  2017年   2篇
  2016年   10篇
  2015年   10篇
  2014年   14篇
  2013年   10篇
  2012年   20篇
  2011年   22篇
  2010年   14篇
  2009年   14篇
  2008年   24篇
  2007年   17篇
  2006年   19篇
  2005年   6篇
  2004年   12篇
  2003年   3篇
  2002年   8篇
  2001年   4篇
  2000年   2篇
  1998年   3篇
  1997年   2篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1989年   1篇
  1976年   1篇
排序方式: 共有257条查询结果,搜索用时 156 毫秒
1.
2.
DNA and FISH (fluorescence in situ hybridization) analysis were carried out in 12 patients with stigmata of Turner syndrome to determine whether the Supernumerary M arker C hromosome (SMC) found cytogenetically in each of these patients was derived from the Y chromosome. The presence of a Y chromosome in these patients may predispose them to develop gonadoblastoma. PCR-Southern blot analysis, followed by FISH, was used to detect the presence of Y chromosome material. The S ex determining R egion Y (SRY), T estis S pecific P rotein Y -encoded (TSPY) and Y -chromosome R NA R ecognition M otif (YRRM) genes, which map at Yp11.31, Yp11.1–11.2 and Yp11.2/Yq11.21–11.23, respectively, were selected as markers, because they span the whole Y chromosome, and more importantly, they are considered to be involved in the development of gonadoblastoma. It was shown that in 12 patients, all of whom had an SMC, the SMC of 11 was derived from the Y chromosome. Furthermore, the presence of the SRY, TSPY and YRRM gene sequences was determined and FISH analysis confirmed the Y origin of the SMCs. The methodology described in this report is a rapid, reliable and sensitive approach which may be easily applied to determine the Y origin of an SMC carried in Turner syndrome. The identification of an SMC is important for the clinical management and prognostic counseling of these patients with Turner syndrome.  相似文献   
3.
Congenital seminal vesicle cysts associated with renal agenesis are uncommon, but are currently detected more frequently with the use of sectional imaging procedures. Approximately 200 cases have been reported. The unique feature of our case is the combination of this disorder with an ipsilateral undescended testis. Our patient underwent partial vesiculectomy, in which the cyst was removed and the seminal vesicle remnant with its vas deferens was preserved. A review of the infertile cases and the impact of surgical treatment on fertility are discussed. Features that render partial vesiculectomy applicable and the potential effect of this procedure on fertility are highlighted.  相似文献   
4.
Violent incidents in acute inpatient units for children and adolescents are a major and persistent problem. The demographic, clinical, and modifiable (environmental–organizational) risk factors that affect inpatient violence in an Acute Child and Adolescent Psychiatric Unit were investigated via a retrospective study. Data were collected from nursing and medical reports and the unit's census and included 100 days per year for 16 years. Incidents of violence and assault types were recorded, and variables such as the diagnostic category of assailants, total number of patients, and staffing factors during the incident were examined. Of the 2390 violent incidents recorded, 50% were attributed to cases of physical violence towards another patient, 17% to physical violence towards nursing staff, 19% to physical violence towards self and 14% to destruction of property. According to the final multivariable model, for each additional patient in the unit, the risk of a violent event increased by 9.51%; for each additional offender patient, the risk increased by 14.06%; the number of assistant nurses was associated with a 25.03% increased risk; and, after 2006, the risk increased by 68.99%. The most significant factor associated with a 59.98% decreased risk was the total number of nursing staff. All variables significantly and independently contributed to the model. Acute inpatient psychiatric units with a small number of hospitalized patients, adequate, well‐trained and specialized nursing staff, and the hospitalization of different types of patients in separate wards or units are expected to facilitate a reduction in the frequency of violent incidents.  相似文献   
5.
Late onset neonatal sepsis (LOS) has a high mortality and the optimal management is poorly defined. We aimed to evaluate new expert panel-derived criteria to define LOS and characterize the current management and antibiotic susceptibility of LOS-causing organisms in Europe. A prospective observational study enrolled infants aged 4 to 90 days in five European countries. Clinical and laboratory findings as well as empiric treatment were recorded and patients were followed until the end of antibiotic therapy. Failure was defined as a change of primary antibiotic, no resolution of clinical signs, appearance of new signs/pathogens or death. Antibiotic therapy was considered appropriate if the organism was susceptible to at least one empiric antibiotic. 113 infants (median age 14 days, 62 % ≤1500 g) were recruited; 61 % were culture proven cases (28 CoNS, 24 Enterobacteriaceae, 11 other Gram-positives and 6 Gram-negative non-fermentative organisms). The predictive value of the expert-panel criteria to identify patients with a culture proven LOS was 61 % (95 % CI 52 % to 70 %). Around one third of Enterobacteriaceae were resistant to ampicillin + or cefotaxime + gentamicin but only 10 % to meropenem. Empiric treatment contained a total of 43 different antibiotic regimens. All-cause mortality was 8 % with an additional 45 % classified as failure of empiric therapy, mainly due to change of primary antibiotics (42/60). Conclusions: The expert panel—derived diagnostic criteria performed well identifying a high rate of culture proven sepsis. Current management of LOS in Europe is extremely variable suggesting an urgent need of evidence-based guidelines.  相似文献   
6.
The presence of Y chromosome sequences in Turner syndrome (TS) patients may predispose them to gonadoblastoma formation with an estimated risk of 15–25%. The aim of this study was to determine the presence and the incidence of cryptic Y chromosome material in the genome of TS patients. The methodology involved a combination of polymerase chain reaction (PCR) and nested PCR followed by Southern blot analysis of three genes—the sex determining region Y (SRY), testis specific protein Y encoded (TSPY) and RNA binding motif protein (RBM) (previously designated as YRRM) and nine additional STSs spanning all seven intervals of the Y chromosome. The methodology has a high sensitivity as it detects one 46, XY cell among 105 46, XX cells. Reliability was ensured by taking several precautions to avoid false positive results. We report the results of screening 50 TS patients and the identification of cryptic Y chromosome material in 12 (24%) of them. Karyotypes were divided in four groups: 5 (23.8%) patients out of the 21 TS patients which have the 45, X karyotype (group A) also have cryptic Y sequences; none (0%) of the 7 patients who have karyotypes with anomalies on one of the X chromosomes have Y mosaicism (group B); 1 (6.3%) of the 16 patients with a mosaic karyotype have Y material (group C); and 6 (100%) out of 6 patients with a supernumerary marker chromosome (SMC) have Y chromosome sequences (group D). Nine of the 12 patients positive for cryptic Y material were recalled for a repeat study. Following new DNA extraction, molecular analysis was repeated and, in conjunction with fluorescent in situ hybridization (FISH) analysis using the Y centromeric specific probe Yc-2, confirmed the initial positive DNA findings. This study used a reliable and sensitive methodology to identify the presence of Y chromosome material in TS patients thus providing not only a better estimate of a patient's risk in developing either gonadoblastoma or another form of gonadal tumor but also the overall incidence of cryptic Y mosaicism.  相似文献   
7.
Classical interferon-alpha has been shown to be correlated with the development of a variety of autoimmune disorders. A 38 year-old female patient developed simultaneously diabetic ketoacidosis and hyperthyroidism 5 mo following initiation of treatment with pegylated interferon-α and ribavirin for chronic hepatitis C. High titers of glutamic acid decarboxylase, antinuclear and thyroid (thyroid peroxidase and thyroglobulin) antibodies were detected. Antiviral treatment was withdrawn and the patient was treated with insulin for insulin-dependent diabetes mellitus and propranolol for hyperthyroidism. Twelve months after cessation of pegylated interferon-α therapy the patient was euthyroid without any medication but remained insulin-dependent.  相似文献   
8.
Microbiota composition and associated metabolic activities are essential for the education and development of a healthy immune system. Microbial dysbiosis, caused by risk factors such as diet, birth mode, or early infant antimicrobial therapy, is associated with the inception of allergic diseases. In turn, allergic diseases increase the risk for irrational use of antimicrobial therapy. Microbial therapies, such as probiotics, have been studied in the prevention and treatment of allergic diseases, but evidence remains limited due to studies with high heterogeneity, strain-dependent effectiveness, and variable outcome measures. In this review, we sketch the relation of microbiota with allergic diseases, the overuse and rationale for the use of antimicrobial agents in allergic diseases, and current knowledge concerning the use of bacterial products in allergic diseases. We urgently recommend 1) limiting antibiotic therapy in pregnancy and early childhood as a method contributing to the reduction of the allergy epidemic in children and 2) restricting antibiotic therapy in exacerbations and chronic treatment of allergic diseases, mainly concerning asthma and atopic dermatitis. Future research should be aimed at antibiotic stewardship implementation strategies and biomarker-guided therapy, discerning those patients that might benefit from antibiotic therapy.  相似文献   
9.
Preimplantation genetic diagnosis (PGD) for monogenic disorders currently involves polymerase chain reaction (PCR)-based methods, which must be robust, sensitive and highly accurate, precluding misdiagnosis. Twelve adverse misdiagnoses reported to the ESHRE PGD-Consortium are likely an underestimate. This retrospective study, involving six PGD centres, assessed the validity of PCR-based PGD through reanalysis of untransferred embryos from monogenic-PGD cycles. Data were collected on the genotype concordance at PGD and follow-up from 940 untransferred embryos, including details on the parameters of PGD cycles: category of monogenic disease, embryo morphology, embryo biopsy and genotype assay strategy. To determine the validity of PCR-based PGD, the sensitivity (Se), specificity (Sp) and diagnostic accuracy were calculated. Stratified analyses were also conducted to assess the influence of the parameters above on the validity of PCR-based PGD. The analysis of overall data showed that 93.7% of embryos had been correctly classified at the time of PGD, with Se of 99.2% and Sp of 80.9%. The stratified analyses found that diagnostic accuracy is statistically significantly higher when PGD is performed on two cells versus one cell (P=0.001). Se was significantly higher when multiplex protocols versus singleplex protocols were applied (P=0.005), as well as for PGD applied on cells from good compared with poor morphology embryos (P=0.032). Morphology, however, did not affect diagnostic accuracy. Multiplex PCR-based methods on one cell, are as robust as those on two cells regarding false negative rate, which is the most important criteria for clinical PGD applications. Overall, this study demonstrates the validity, robustness and high diagnostic value of PCR-based PGD.  相似文献   
10.
Over an 18-year period, 10 myelodysplastic syndrome (MDS) patients with complex hyperdiploid karyotypes were identified. According to the FAB classification, the 10 patients were subclassified as three refractory anemias (RA), three refractory anemias with excess blasts (RAEB), two RAEB in transformation (RAEB-t), and two unclassified MDS. According to the WHO classification, the diagnoses were two RA, one refractory cytopenia with multilineage dysplasia, two RAEB-1, one RAEB-2, two unclassified MDS, and two acute myeloid leukemia. Six were secondary MDS. Four patients showed marked dyserythropoiesis; three of these were secondary MDS. The chromosome number ranged from 47 to 62, and clonal evolution or composite karyotypes were noted in 7 patients. Seven patients had at least one clone with >50 chromosomes. Recurrent defects included chromosome 5, 17, and 13 abnormalities. Notably, trisomy 8 and monosomy 7 were rare in that group of patients. Three of four patients with marked dyserythropoiesis shared abnormalities of both chromosomes 13 and 17.  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