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   179篇
  免费   45篇
  国内免费   1篇
儿科学   17篇
妇产科学   1篇
基础医学   36篇
口腔科学   4篇
临床医学   39篇
内科学   42篇
皮肤病学   4篇
神经病学   6篇
特种医学   13篇
外科学   7篇
综合类   10篇
预防医学   26篇
药学   4篇
肿瘤学   16篇
  2021年   3篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2017年   5篇
  2016年   3篇
  2015年   3篇
  2014年   6篇
  2013年   11篇
  2012年   3篇
  2011年   6篇
  2010年   8篇
  2009年   8篇
  2008年   9篇
  2007年   3篇
  2006年   4篇
  2004年   6篇
  2003年   2篇
  2002年   3篇
  2001年   2篇
  1999年   6篇
  1998年   5篇
  1997年   7篇
  1995年   3篇
  1993年   6篇
  1992年   2篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   5篇
  1986年   6篇
  1985年   3篇
  1984年   4篇
  1983年   4篇
  1982年   8篇
  1981年   3篇
  1979年   4篇
  1978年   6篇
  1977年   5篇
  1976年   5篇
  1975年   5篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1966年   3篇
  1965年   3篇
  1940年   1篇
排序方式: 共有225条查询结果,搜索用时 15 毫秒
1.
2.
The modulation of drug metabolising enzymes by Masheri extract (ME) and Benzo(a)Pyrene [B(a)P] was studied in male Sprague Dawley rats fed different dietary protein levels. Two groups of 21 days old male Sprague Dawley rats were put on a high protein diet (SHP) with 20% Casein, and a low protein diet (SLP) with 3% Casein semisynthetic based diets for 12 weeks. The SLP fed animals showed lower basal levels of the Phase I activating enzymes viz. Cytochrome P450, Benzo(a)Pyrene hydroxylase, Benzphetamine demethylase and Phase II glutathione detoxification system viz. Glutathione (GSH) and Glutathione-S-transferase. ME and B(a)P treatment significantly depleted the glutathione detoxification system in the SLP group whereas an opposite effect was observed in the SHP group. Interstingly, ME and B(a)P treated rats in the SLP group showed a higher percent increase in the hepatic and pulmonary Phase I enzyme activities than those observed in the treated ME/B(a)P treated SHP rats. Furthermore, both ME and B(a)P significantly decreased the hepatic pool of vitamin A while a concomittant increase in that of vitamin C was observed.  相似文献   
3.
Classical and anaplastic seminoma: difference in survival   总被引:1,自引:0,他引:1  
Bobba  VS; Mittal  BB; Hoover  SV; Kepka  A 《Radiology》1988,167(3):849-852
Classical and anaplastic seminoma are traditionally treated with radiation therapy and are said to have the same prognosis. A retrospective study was undertaken of 90 seminoma patients treated with radiation therapy between 1961 and 1985. The classical group consisted of 71 patients of whom 50 had stage I and 21 had stage II disease. The anaplastic group consisted of 19 patients of whom ten had stage I and nine had stage II disease. The median follow-up time was 64 months for the entire group. The 10-year relapse-free survival rate for the classical group was 94% and for the anaplastic group was 70% (P less than .05). For patients with classical stage I disease, the relapse-free actuarial survival rate was 98%; for patients with anaplastic stage I disease, it was 64% (P less than .02). For the classical stage II disease group, the relapse-free actuarial survival rate was 84% and for the anaplastic stage II disease group, 75% (P less than .70). Four patients in the classical group (6%) had relapses; of these, one patient had local recurrence of tumor, and three had distant metastases. In the anaplastic group, four patients (21%) had relapses; two patients had local recurrence of tumor, and two had distant metastases. Therefore the data suggest a difference in survival and relapse rates between classical and anaplastic seminoma.  相似文献   
4.
白玉杰  Seetha SV  Vamla B  高庆生 《医学争鸣》2003,24(20):1845-1848
目的:应用酵母双杂交方法筛选BRCA2相互作用蛋白编码基因,验证其相互作用并研究其功能联系。方法:以BRCA2基因3′端片段构建酵母双杂交质粒,筛选正常人乳腺上皮细胞cDNA库,获得编码相互作用蛋白的基因,采用免疫共沉淀、哺乳细胞双杂交和荧光酶测定等方法进一步验证蛋白间相互作用和功能联系.结果:采用酵母双杂交系统筛选,获得了多个编码BRCA2相互作用蛋白的基因,其中包括已知的FHL2蛋白;免疫共沉淀和哺乳动物细胞双杂交试验显示BRCA2和FHL2在体内特异性结合,并证实FHL2在体内形成同源二聚体;转录活性分析发现BRCA2与FHL2有协同转录激活作用。结论:发现BRCA2与FHL2蛋白间相互作用和功能联系,为BRCA2功能研究提供了新的方向。  相似文献   
5.
Exoantigens from 10-day-old cultures of 100 isolates of pathogenic and saprophytic dematiaceous fungi were analyzed by the exoantigen test. Antisera to Cladosporium bantianum ATCC 10958, Fonsecaea pedrosoi CDC AMO-B06, and Phialophora verrucosa CDC AMO-C12 were prepared in New Zealand rabbits immunized with soluble antigens from 1-month-old cultures. Absorbed and nonabsorbed antisera and exoantigens from the same organisms were used as reference reagents. Serologic reactions were analyzed in terms of the presence or absence of lines of identity or nonidentity. These reactions allowed presumptive differentiation of C. bantianum, F. pedrosoi, and Phialophora verrucosa from other dematiaceous fungi, including Cladosporium spp. (28 isolates), Exophiala spp. (18 isolates), Fonsecaea spp. (17 isolates). Lecythophora hoffmannii (4 isolates), Phaeoannellomyces werneckii (3 isolates), Phialophora spp. (17 isolates), Wangiella dermatitidis (9 isolates), and Rhinocladiella spp. (4 isolates).  相似文献   
6.
In an epidemiological study, nine isolates of dematiaceous fungi were recovered from the interior of a local feed and seed warehouse. Sample sites include brick walls and floors. Air samples also were included. Samples were collected in saline and plated on Mycobiotic and Sabouraud agar. The nine dematiaceous fungi recovered from these samples were identified with microscopic morphology, thermotolerance, biochemical reactions, and animal virulence test. Four isolates were identified as nonpathogens on the basis of positive gelatin tests. The identified pathogens included Fonsecaea pedrosoi, Cladosporium bantianum (C trichoides), Wangiella dermatitidis (Dixon et al., Mycopathologia 70:153-161, 1980), and Exophiala jeanselmei. These five organisms were injected into NCI/ALB mice. Only the isolate of C. bantianum was neurotropic, as demonstrated histopathologically and by the recovery of the organism from brain tissue. None of the remaining four isolates were seen or cultured from any of the mouse tissues analyzed. The recovery of pathogenic dematiaceous fungi from environmental sites is not uncommon. However, this study is noteworthy in that it represents only the second reported isolation of C. bantianum and the first isolation of F. pedrosoi from the environment in North America and suggests that these fungi may be more ubiquitous in this region that previously believed.  相似文献   
7.
The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.   相似文献   
8.
Of 90 clinical isolates of Cryptococcus neoformans studied, 3 were determined to be serotype B/C. The patients from whom these B/C isolates were obtained were identified as never having lived in or visited the areas associated with B/C serotypes. This finding suggests a broader geographic distribution of this serotype group than previously believed. The glycine-cycloheximide-phenol red medium described by Salkin and Hurd (J. Clin. Microbiol. 15:169-171, 1982) was shown to be more accurate in differentiating A/D and B/D serotype pairs of C. neoformans than the creatinine-dextrose-bromthymol blue medium described by Kwon-Chung et al. (Int. J. Syst. Bacteriol. 28:616-620, 1978).  相似文献   
9.
Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165  相似文献   
10.

Aims:

To examine the variation in risk factors and hospitalization costs among four elderly dementia cohorts by race and gender.

Materials and Methods:

The 2008 Tennessee Hospital Discharged database was examined. The prevalence, risk factors and cost of inpatient care of dementia were examined for individuals aged 65 years and above, across the four race gender cohorts - white males (WM), black males (BM), white females (WF), and black females (BF).

Results:

3.6% of patients hospitalized in 2008 had dementia. Dementia was higher among females than males, and higher among blacks than whites. Further, BF had higher prevalence of dementia than WF; similarly, BM had a higher prevalence of dementia than WM. Overall, six risk factors were associated with dementia for the entire sample including HTN, DM, CKD, CHF, COPD, and stroke. These risk factors varied slightly in predicting dementia by race and gender. Hospital costs were 14% higher among dementia patients compared to non-dementia patients.

Conclusions:

There exist significant race and gender disparities in prevalence of dementia. A greater degree of co-morbidity, increased duration of hospital stay, and more frequent hospitalizations, may result in a higher cost of inpatient dementia care. Aggressive management of risk factors may subsequently reduce stroke and cost of dementia care, especially in the black population. Race and gender dependent milestones for management of these risk factors should be considered.  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