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   503篇
  免费   36篇
  国内免费   8篇
儿科学   51篇
妇产科学   3篇
基础医学   52篇
口腔科学   11篇
临床医学   71篇
内科学   97篇
皮肤病学   2篇
神经病学   8篇
特种医学   136篇
外科学   24篇
综合类   8篇
预防医学   20篇
眼科学   5篇
药学   27篇
中国医学   2篇
肿瘤学   30篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2018年   3篇
  2017年   2篇
  2016年   3篇
  2015年   6篇
  2014年   7篇
  2013年   10篇
  2012年   6篇
  2011年   7篇
  2010年   11篇
  2009年   14篇
  2008年   6篇
  2007年   7篇
  2006年   8篇
  2005年   9篇
  2004年   5篇
  2003年   7篇
  2002年   6篇
  2001年   5篇
  2000年   5篇
  1999年   8篇
  1998年   38篇
  1997年   59篇
  1996年   40篇
  1995年   32篇
  1994年   34篇
  1993年   25篇
  1992年   12篇
  1991年   10篇
  1990年   3篇
  1989年   17篇
  1988年   19篇
  1987年   16篇
  1986年   19篇
  1985年   19篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1978年   6篇
  1977年   8篇
  1976年   4篇
  1975年   5篇
排序方式: 共有547条查询结果,搜索用时 15 毫秒
81.
低聚果糖口服补液盐的试制   总被引:8,自引:0,他引:8  
目的:改良口服补液盐(ORS),使其具有微生态调节作用、并与肠道内渗透压相似。方法:将氯化钠2.6g、氯化钾1.5g、枸橼酸钠2.9g、低聚果糖(FOS)20g和葡萄糖10g等混合后低聚果糖口服液盐(FOS-ORS)。密封包装,使用时加开水1000ml冲服。可采用高效液相色谱法测定FOS的含量。结果:FOS-ORS为白色散剂,加水后为无色透明液体,味甜中微咸,其浓度(mmol/L)为钠75、钾20  相似文献   
82.
Purine nucleoside phosphorylase deficiency is an inherited disease of purine metabolism characterized clinically as combined immunodeficiency. The molecular defects have been published for 4 different alleles in 3 patients. We report four new mutations including two amino acid substitutions, A 174P and G190V, a single codon deletion, ΔI129, and a point mutation in intron 3 which leads to aberrant splicing and creation of a premature stop codon in exon 4 (286 -18G→A). Of the previously reported mutations, E89K was found in one additional patient, and R234P was found in 3 unrelated patients, making R234P the most common mutation reported to date in this disease. Hum Mutat 9:118–121, 1997. © 1997 Wiley-Liss, Inc.  相似文献   
83.
Confidential enquiries into poor perinatal outcomes have identified deficiencies in team working as a common factor and have recommended team training in the management of obstetric emergencies. Isolated aviation-based team training programmes have not been associated with improved perinatal outcomes when applied to labour ward settings, whereas obstetric-specific training interventions with integrated teamwork have been associated with clinical improvements. This commentary reviews obstetric emergency training programmes from hospitals that have demonstrated improved outcomes to determine the active components of effective training. The common features identified were: institution-level incentives to train; multi-professional training of all staff in their units; teamwork training integrated with clinical teaching and use of high fidelity simulation models. Local training also appeared to facilitate self-directed infrastructural change.  相似文献   
84.
Aim:  Delivery by C-section (CS) has been associated with increased risk for allergy, diabetes and leukaemia. Whereas the underlying cause is unknown, epigenetic change of the genome has been suggested as a candidate molecular mechanism for perinatal contributions to later disease risk. We hypothesized that mode of delivery affects epigenetic activity in newborn infants.
Methods:  A total of 37 newborn infants were included. Spontaneous vaginal delivery (VD) occurred in 21, and 16 infants were delivered by elective CS. Blood was sampled from the umbilical cord and 3–5 days after birth. DNA-methylation was analyzed in leucocytes.
Results:  Infants born by CS exhibited higher DNA-methylation in leucocytes compared with that of those born by VD (p < 0.001). After VD, newborn infants exhibited stable levels of DNA-methylation, as evidenced by comparing cord blood values with those 3–5 days after birth (p = 0.55). On postnatal days 3–5, DNA-methylation had decreased in the CS group (p = 0.01) and was no longer significantly different from that of VD (p = 0.10).
Conclusion:  DNA-methylation is higher in infants delivered by CS than in infants vaginally born. Although currently unknown how gene expression is affected, or whether epigenetic differences related to mode of delivery are long-lasting, our findings open a new area of clinical research with potentially important public health implications.  相似文献   
85.
86.
Factors influencing women to undergo screening mammography   总被引:2,自引:0,他引:2  
  相似文献   
87.
88.
89.
The immunophenotypes of lymphoblasts from children with newly diagnosed T-cell acute lymphoid leukemia (T-ALL, n = 101) or T-cell non-Hodgkin lymphoma (T-NHL, n = 31) were analyzed to correlate stage of thymocyte differentiation with clinical features and outcome. The 67 boys and 34 girls with T-ALL were 1 month to 18 years old (median, 8 years) with leukocyte counts ranging from 2 to 810 x 10(9)/L (median, 55 x 10(9)/L). Eighteen of these patients were black, and 70 had a mediastinal mass. Twenty-six boys and five girls with a median age of 9 years (range, 1 to 20 years) had T-NHL. Seven of these patients were black, and 24 had a mediastinal mass. The distributions of thymocyte developmental stages (early [CD7+], intermediate [CD1+ and/or CD4+ and/or CD8+], and mature [CD3+]) in cases of T-ALL and T-NHL were significantly different: 34%, 43%, and 23% v 6%, 62%, and 32% (P = .02). A comparison of the patients' clinical features according to the maturational stage of thymocytes failed to disclose significant differences in the majority of characteristics studied. However, patients with mature-stage T-NHL, with or without the addition of subjects with mature-stage T-ALL, were less likely to have a mediastinal mass (P = .02 for both comparisons). Those with intermediate-stage T-cell malignancy (T-ALL and T-NHL combined) were the subgroup most likely to have a mediastinal mass (P = .01). Response to remission induction therapy was significantly worse in the T-ALL subgroup with an early-stage phenotype: a failure rate of 21% v 0% and 6% for the two more differentiated phenotypic subgroups (P = .007). Event-free survival was not affected by thymocyte maturational stage in cases of either T-ALL or T-NHL. Despite evidence of clinical heterogeneity among the maturational stages of T-cell malignancies in children, these developmental subdivisions do not appear to be critical determinants of outcome once remission is achieved. We conclude that such phenotypes need not be included in the stratification plans for clinical trials using common induction treatment.  相似文献   
90.
Glomus tympanicum chemodectomas: radiographic and clinical characteristics   总被引:2,自引:0,他引:2  
Larson  TC  d; Reese  DF; Baker  HL  Jr; McDonald  TJ 《Radiology》1987,163(3):801-806
Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.  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