全文获取类型
收费全文 | 609篇 |
免费 | 63篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 50篇 |
妇产科学 | 7篇 |
基础医学 | 62篇 |
口腔科学 | 27篇 |
临床医学 | 62篇 |
内科学 | 145篇 |
皮肤病学 | 19篇 |
神经病学 | 19篇 |
特种医学 | 79篇 |
外科学 | 76篇 |
综合类 | 18篇 |
预防医学 | 31篇 |
药学 | 53篇 |
肿瘤学 | 21篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 21篇 |
2013年 | 26篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 44篇 |
2009年 | 29篇 |
2008年 | 22篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 9篇 |
1998年 | 28篇 |
1997年 | 35篇 |
1996年 | 34篇 |
1995年 | 28篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 19篇 |
1988年 | 13篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有678条查询结果,搜索用时 15 毫秒
11.
Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats 总被引:4,自引:1,他引:4
Harris AJ; Shaddock JG; Manjanatha MG; Lisenbey JA; Casciano DA 《Carcinogenesis》1998,19(8):1451-1458
Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is
a contaminant of the human food supply, particularly in parts of Africa and
Asia. AFB1-induced changes in gene expression may play a part in the
development of the toxic, immunosuppressive and carcinogenic properties of
this fungal metabolite. An understanding of the-role of AFB1 in modulating
gene regulation should provide insight regarding mechanisms of AFB1-induced
carcinogenesis. We used three PCR- based subtractive techniques to identify
AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential
display PCR (DD-PCR), representational difference analysis (RDA) and
suppression subtractive hybridization (SSH). Each of the three techniques
identified AFB1- responsive genes, although no individual cDNA was isolated
by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH
were found to represent eight genes that are differentially expressed as a
result of AFB1 exposure. Genes whose mRNA levels were increased in cultured
primary rat hepatocytes after AFB1 treatment were corticosteroid binding
globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin,
C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase
Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels
after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When
liver RNA from AFB1-treated male F344 rats was evaluated for transferrin,
CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and
an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen.
Analysis of the potential function of these genes in maintaining cellular
homeostasis suggests that their differential expression could contribute to
the toxicity associated with AFB1 exposure.
相似文献
12.
BackgroundAcute abdomen is a major surgical problem in Ethiopia with surgery for acute abdominal conditions accounting for roughly one-third of total emergency operations in many centers. This study was conducted with the aim of studying the pattern and outcome of surgically managed acute abdominal cases in a private general hospital in Addis Ababa, Ethiopia.MethodsThis was a retrospective cross-sectional study of acute abdominal cases in adult patients operated at Teklehaimanot General Hospital between January 1, 2018 and August 1, 2019.ResultsA total of 267 patients'' medical records were reviewed. The male to female ratio was 1.5:1 and majority of patients were between the age range of 20 to 40 years with mean age of 36±16 years. The average duration of symptoms before arrival was 71.1±84.4 hours (range 3 to 504 hours) and only 85 (31.8%) of patients reached to the Hospital within 24 hours or less of onset of symptoms. Acute appendicitis was the most common cause of acute abdomen; observed in 193 (72.3%) of the cases. Overall post-operative complication rate was 14.8% and post-operative mortality rate was 1.9%. It was found that delayed presentation (OR 2.01, 95% CI 1.64–7.84), old age (OR 1.51, 95% CI 1.89–3.59), and tachycardia at presentation (OR 2.85, 95% CI 1.03–6.82) were major predictors of morbidity and mortality in operated patients.ConclusionIn this study acute appendicitis accounted for the majority of cases operated for acute abdomen. Length of post-operative hospital stay, early post-operative complication rate, and overall mortality rate were found to be significantly lower in our series than other reports. 相似文献
13.
G Eyob H Guebrexabher E Lemma D Wolday M Gebeyehu G Abate L Rigouts D van Soolingen A Fontanet E Sanders J W Dorigo-Zetsma 《The international journal of tuberculosis and lung disease》2004,8(11):1388-1391
From a prospective cohort study on tuberculosis/human immunodeficiency virus (TB/HIV) interaction in Addis Ababa, Ethiopia, drug susceptibility results were available for 94 TB patients (46% HIV-infected). Resistance to one or more drug(s) was detected in 21 (22.3%) and multidrug resistance in five (5.3%) patients. Occurrence of resistance was not related to HIV status or outcome after 24 months of follow-up. However, among HIV-infected TB patients who died during follow-up, survival time in those with a resistant Mycobacterium tuberculosis strain was significantly shorter compared to those with a sensitive strain (6 vs. 13 months). Early detection of drug resistance and timely treatment change can therefore have a positive impact on survival in HIV-infected TB patients. 相似文献
14.
Aysheshm Kassahun Jovana Sadlova Vit Dvorak Tatiana Kostalova Iva Rohousova Daniel Frynta Tatiana Aghova Daniel Yasur-Landau Wessenseged Lemma Asrat Hailu Gad Baneth Alon Warburg Petr Volf Jan Votypka 《Acta tropica》2015
Human visceral (VL, also known as Kala-azar) and cutaneous (CL) leishmaniasis are important infectious diseases affecting countries in East Africa that remain endemic in several regions of Ethiopia. The transmission and epidemiology of the disease is complicated due to the complex life cycle of the parasites and the involvement of various Leishmania spp., sand fly vectors, and reservoir animals besides human hosts. Particularly in East Africa, the role of animals as reservoirs for human VL remains unclear. Isolation of Leishmania donovani parasites from naturally infected rodents has been reported in several endemic countries; however, the status of rodents as reservoirs in Ethiopia remains unclear. Here, we demonstrated natural Leishmania infections in rodents. Animals were trapped in 41 localities of endemic and non-endemic areas in eight geographical regions of Ethiopia and DNA was isolated from spleens of 586 rodents belonging to 21 genera and 38 species. Leishmania infection was evaluated by real-time PCR of kinetoplast (k)DNA and confirmed by sequencing of the PCR products. Subsequently, parasite species identification was confirmed by PCR and DNA sequencing of the 18S ribosomal RNA internal transcribed spacer one (ITS1) gene. Out of fifty (8.2%) rodent specimens positive for Leishmania kDNA-PCR and sequencing, 10 were subsequently identified by sequencing of the ITS1 showing that five belonged to the L. donovani complex and five to L. tropica. Forty nine kDNA-positive rodents were found in the endemic localities of southern and eastern Ethiopia while only one was identified from northwestern Ethiopia. Moreover, all the ten ITS1-positive rodents were captured in areas where human leishmaniasis cases have been reported and potential sand fly vectors occur. Our findings suggest the eco-epidemiological importance of rodents in these foci of leishmaniasis and indicate that rodents are likely to play a role in the transmission of leishmaniasis in Ethiopia, possibly as reservoir hosts. 相似文献
15.
16.
17.
Breast cancer is the most common cause of cancer death in women in this country. Until recently, the traditional treatment has been radical surgery with or without radiation therapy for patients with primary breast cancer, and palliative endocrine therapy followed by chemotherapy for patients with advanced disease. These treatments have met with limited effectiveness in terms of eradicating the disease. Studies in the past decade have given cause for optimism for breast cancer patients. Adjuvant systemic therapy after local treatment appears promising for certain subsets of patients with primary breast cancer. The development of estrogen receptor assays has markedly changed our approach to the disease and improved patient care. Estrogen receptor is an important prognostic factor and is useful in planning appropriate therapy for patients with primary breast cancer as well as those with advanced disease. Further research is urgently needed to improve the dismal survival of certain women with this common malignancy. 相似文献
18.
19.
20.
Pre‐therapy inflammation and coagulation activation and long‐term CD4 count responses to the initiation of antiretroviral therapy 下载免费PDF全文