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   301篇
  免费   20篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   9篇
妇产科学   3篇
基础医学   30篇
口腔科学   26篇
临床医学   35篇
内科学   65篇
皮肤病学   2篇
神经病学   5篇
特种医学   72篇
外科学   13篇
综合类   7篇
预防医学   12篇
眼科学   1篇
药学   14篇
中国医学   3篇
肿瘤学   28篇
  2023年   2篇
  2022年   7篇
  2021年   11篇
  2020年   4篇
  2019年   7篇
  2018年   10篇
  2017年   9篇
  2016年   8篇
  2015年   3篇
  2014年   14篇
  2013年   15篇
  2012年   7篇
  2011年   8篇
  2010年   10篇
  2009年   9篇
  2008年   9篇
  2007年   10篇
  2006年   7篇
  2005年   12篇
  2004年   4篇
  2003年   5篇
  2002年   5篇
  2000年   4篇
  1999年   2篇
  1998年   8篇
  1997年   12篇
  1996年   12篇
  1995年   11篇
  1994年   13篇
  1993年   15篇
  1992年   3篇
  1991年   4篇
  1990年   8篇
  1989年   11篇
  1988年   10篇
  1987年   5篇
  1986年   3篇
  1985年   7篇
  1983年   4篇
  1982年   4篇
  1981年   1篇
  1980年   3篇
  1978年   2篇
  1976年   5篇
  1975年   1篇
  1973年   2篇
排序方式: 共有326条查询结果,搜索用时 15 毫秒
31.
Rybicki  AC; Qiu  JJ; Musto  S; Rosen  NL; Nagel  RL; Schwartz  RS 《Blood》1993,81(8):2155-2165
Red blood cell (RBC) protein 4.2 deficiency is often associated with a moderate nonimmune hemolytic anemia, splenomegaly, and osmotically fragile RBCs resembling, but not identical to, hereditary spherocytosis (HS). In the Japanese type of protein 4.2 deficiency (protein 4.2Nippon), the anemia is associated with a point mutation in the protein 4.2 cDNA. In this report, we describe a patient with moderate and apparently episodic nonimmune hemolytic anemia with splenomegaly, spherocytosis, osmotically fragile RBCs, reduced whole cell deformability, and abnormally dense cells. Sodium dodecyl sulfate- polyacrylamide gel electrophoresis analysis of the proposita's RBC membrane proteins showed an 88% deficiency of protein 4.2 and a 30% deficiency of glyceraldehyde-3-phosphate dehydrogenase (band 6). Structural and molecular analyses of the proposita's protein 4.2 were normal. In contrast, limited tryptic digestion of the proposita's band 3 showed a homozygous abnormality in the cytoplasmic domain. Analysis of the pedigree disclosed six members who were heterozygotes for the band 3 structural abnormality and one member who was a normal homozygote. Direct sequence analysis of the abnormal band 3 tryptic peptide suggested that the structural abnormality resided at or near residue 40. Sequence analysis of the proposita's band 3 cDNA showed a 232G-->A mutation resulting in a 40glutamic acid-->lysine substitution (band 3Montefiore). Allele-specific oligonucleotide hybridization was used to probe for the mutation in the pedigree, showing that the proposita was homozygous, and the pedigree members who were heterozygous for the band 3 structural abnormality were also heterozygous for the band 3Montefiore mutation. The band 3Montefiore mutation was absent in 26 chromosomes from race-matched controls and in one pedigree member who did not express the band 3 structural abnormality. In coincidence with splenectomy, the proposita's anemia was largely corrected along with the disappearance of most spherocytes and considerable improvements of RBC osmotic fragility, whole cell deformability, and cell density. We conclude that this hereditary hemolytic anemia is associated with the homozygous state for band 3Montefiore (40glutamic acid-->lysine) and a decreased RBC membrane content of protein 4.2. We speculate that band 3 structural abnormalities can result in defective interactions with protein 4.2 and band 6, and in particular, that the region of band 3 containing 40glutamic acid is involved directly or indirectly in interactions with these proteins.  相似文献   
32.
33.
34.
Pilocarpine HCl has been shown to stimulate parotid and submandibular gland salivary flow. The purpose of this study was to determine whether this cholinergic-muscarinic drug also stimulates labial (minor) salivary gland (LSG) flow and to relate that with whole unstimulated salivary (WUS) flow rateS. Subjects diagnosed with primary Sjögren's syndrome (SS-1; n = 9) or secondary Sjögren's syndrome (SS-2; n = 9) were enrolled in this study after meeting stringent enrollment criteria. An age-gender matched control group was also enrolled. The labial saliva was collected in a standardized manner on Per-iopaper® for 5 min and the volume was analysed by the Periotron®.Whole unstimulated salivary samples were collected for 5 min by the method of Mandel and Wot-man (1976).Each subject was dosed with pilocarpine HCl (5 mg; tablets; p.o.).After 60 min the LSG flow as well as the WUS flow was determined again as previously. The results indicated a significant (>180%) increase in both labial salivary gland flow as well as whole salivary flow in the SS-1 and SS-2 subjects (mean ± S. e.m.): [SS-1: WUS = 0.1080 ± 0.03 vs 0.2242 ± 0.03 ml per 5 min; LSG = 93.1 ± 22.2 vs 167.8 ± 15.9 μl/5 min; P < 0.001; SS-2: WUS = 0.1384 ± 0.02 vs 0.2775 ± 0.09 ml per 5 min; LSG = 97.7 ± 20.2 vs 182.8 ± 17.9 μl per 5 min; P < 0.001]. These results indicate a significant increase in labial salivary gland flow as well as whole salivary flow as stimulated by pilocarpine HCI in Sjögren's syndrome patients.  相似文献   
35.
36.
Objective: Meticillin‐resistant staphylococcus aureus (MRSA) colonization on neonatal units is a common and important clinical problem. Effectiveness of polymerase chain reaction (PCR) for detecting MRSA nasal colonization of infants was evaluated and compared to culture‐based methods. The effect of skin decolonization in affected infants was studied. Methods: Paired nasal swabs were collected from infants in our neonatal unit over a 12‐month period (September 2007–2008). Colonization with MRSA was determined with a commercially available PCR method and compared to culture. Results: A total of 696 paired nasal swabs were taken. Three infants were colonized at the beginning and were included. There were positive PCRs in 12 infants. Five infants cultured MRSA from a nasal swab at the same time. No infants were culture‐positive when PCR was negative (sensitivity 100%, specificity 99% compared to culture). PCR results were available within 24 h. Five infants were PCR+ and isolated meticillin‐sensitive Staphylococcus aureus. This organism gave a false‐positive PCR result. Two infants transferred in on broad‐spectrum antibiotics were PCR+ and negative by culture. Decolonization led to negative nasal PCR and culture in 4/5 infants to discharge. Conclusions: PCR methods are sensitive and specific for detection of MRSA colonization in newborn infants of all gestations with results 1–2 days before culture.  相似文献   
37.
38.
Introduction : HIV pre‐exposure prophylaxis (PrEP) has emerged as a key component of contemporary HIV combination prevention strategies. To explore the local suitability of PrEP, country‐specific acceptability studies are needed to inform potential PrEP implementation. In the context of Myanmar, in addition to resource constraints, HIV service access by gay men, other men who have sex with men, and transgender women (GMT) continues to be constrained by legislative and community stigma and marginalization. We aimed to determine PrEP acceptability among GMT in Myanmar and explore the factors associated with willingness to use PrEP. Methods : GMT were recruited in Yangon and Mandalay through local HIV prevention outreach programmes in November and December 2014. Quantitative surveys were administered by trained peer educators and collected data on demographics, sexual risk, testing history and PrEP acceptability. A modified six‐item PrEP acceptability scale classified self‐reported HIV undiagnosed GMT as willing to use PrEP. Multivariable logistic regression identified factors associated with willingness to use PrEP. Results : Among 434 HIV undiagnosed GMT, PrEP awareness was low (5%). PrEP acceptability was high, with 270 (62%) GMT classified as willing to use PrEP. GMT recruited in Mandalay (adjusted odds ratio (aOR) = 1.79; 95%CI = 1.05–3.03), who perceived themselves as likely to become HIV positive (aOR = 1.82; 95%CI = 1.10–3.02), who had more than one recent regular partner (aOR = 2.94; 95%CI = 1.41–6.14), no regular partners (aOR = 2.05; 95%CI = 1.10–3.67), more than five casual partners (aOR = 2.05; 95%CI = 1.06–3.99) or no casual partners (aOR = 2.25; 95%CI = 1.23–4.11) were more likely to be willing to use PrEP. The association between never or only occasionally using condoms with casual partners and willingness to use PrEP was marginally significant (aOR = 2.02; 95%CI = 1.00–4.10). GMT who reported concern about side effects and long‐term use of PrEP were less likely (aOR = 0.35; 95%CI = 0.21–0.59) to be willing to use PrEP. Conclusions : This is the first study to assess PrEP acceptability in Myanmar. Findings suggest PrEP is an acceptable prevention option among GMT in Myanmar, providing they are not required to pay for it. Implementation/demonstration projects are needed to explore the feasibility and cost‐effectiveness of PrEP as a prevention option for GMT in Myanmar.  相似文献   
39.
Fibrosing alveolitis: CT-pathologic correlation   总被引:13,自引:0,他引:13  
Muller  NL; Miller  RR; Webb  WR; Evans  KG; Ostrow  DN 《Radiology》1986,160(3):585-588
Computed tomography (CT) was performed within 10 days of open lung biopsy in nine patients with fibrosing alveolitis. One-centimeter collimation contiguous scans through the chest were obtained in all patients. Additional 1.5-mm collimation scans were obtained in the area in which lung biopsy was later performed in six patients. In seven patients, CT demonstrated patchy involvement of the lung parenchyma, areas with a reticular pattern being intermingled with areas of normal lung. The reticular pattern was associated with cystic spaces 2-4 mm in diameter and was more severe in the lung periphery. Histologically, the reticular pattern corresponded to areas of irregular fibrosis. One patient had diffuse honeycombing (2-20-mm cysts), and one had honeycombing only in the lung periphery. In all patients, CT clearly defined the architectural changes seen on open lung biopsy. These changes were much better seen on the 1.5-mm than on the 10-mm collimation scans. CT may be helpful in determining the pattern and distribution of lung involvement in patients with fibrosing alveolitis and in guiding the surgeon to the most appropriate area(s) for biopsy.  相似文献   
40.
Muller  NL; Chiles  C; Kullnig  P 《Radiology》1990,175(2):335-339
In 14 patients with biopsy-proved lymphangiomyomatosis, disease extent at computed tomography (CT) was correlated with findings at chest radiography and pulmonary-function testing. The CT scans and chest radiographs were read independently by two chest radiologists. Disease extent was assessed on CT scans by using a visual score (0%-100% involvement of the lung parenchyma) and on radiographs by using an adaptation of the International Labour Office classification of the pneumoconioses. There was good concordance between the two observers for CT and radiographic scores (Kendall tau greater than or equal to .86, P less than .01). A significant but relatively low correlation was present between CT findings and radiographic severity of disease (r = .59, P less than .05). Impairment in gas exchange as assessed with the diffusing capacity correlated better with disease extent seen on CT scans (r = .69) than with chest radiographic findings (r = .59). Three patients had evidence of parenchymal disease on the CT scans but not on the radiographs. In one patient CT findings were negative despite a positive finding on chest radiographs. The authors conclude that CT is superior to chest radiography in the assessment of patients with lymphangiomyomatosis.  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