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   476篇
  免费   31篇
  国内免费   4篇
耳鼻咽喉   5篇
儿科学   7篇
妇产科学   5篇
基础医学   80篇
临床医学   42篇
内科学   158篇
皮肤病学   7篇
神经病学   32篇
特种医学   5篇
外科学   40篇
综合类   2篇
预防医学   26篇
眼科学   4篇
药学   27篇
中国医学   1篇
肿瘤学   70篇
  2023年   2篇
  2022年   4篇
  2021年   11篇
  2020年   9篇
  2019年   13篇
  2018年   17篇
  2017年   9篇
  2016年   8篇
  2015年   12篇
  2014年   23篇
  2013年   20篇
  2012年   40篇
  2011年   29篇
  2010年   21篇
  2009年   16篇
  2008年   27篇
  2007年   20篇
  2006年   18篇
  2005年   19篇
  2004年   27篇
  2003年   31篇
  2002年   27篇
  2001年   22篇
  2000年   15篇
  1999年   16篇
  1998年   5篇
  1997年   6篇
  1996年   4篇
  1995年   2篇
  1994年   4篇
  1993年   2篇
  1992年   5篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   3篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1980年   1篇
  1978年   1篇
  1973年   1篇
排序方式: 共有511条查询结果,搜索用时 15 毫秒
11.
OBJECTIVE: Cirrhotic patients with refractory ascites (RA) have a poor prognosis, although individual survival varies greatly. A model that could predict survival for patients with RA would be helpful in planning treatment. Moreover, in cases of potential liver transplantation, a model of these characteristics would provide the bases for establishing priorities of organ allocation and the selection of patients for a living donor graft. Recently, we developed a model to predict survival of patients with RA. The aim of this study was to establish its generalizability for predicting the survival of patients with RA. METHODS: The model was validated by assessing its performance in an external cohort of patients with RA included in a multicenter, randomized, controlled trial that compared large-volume paracentesis and peritoneovenous shunt. The values for actual and model-predicted survival of three risk groups of patients, established according to the model, were compared graphically and by means of the one-sample log-rank test. RESULTS: The model provided a very good fit to the survival data of the three risk groups in the validation cohort. We also found good agreement between the survival predicted from the model and the observed survival when patients treated with peritoneovenous shunt and with paracentesis were considered separately. CONCLUSION: Our survival model can be used to predict the survival of patients with RA and may be a useful tool in clinical decision making, especially in deciding priority for liver transplantation.  相似文献   
12.
Granulocytic sarcomas (GS) are tumor masses of immature myeloid cells presenting at an extramedullary site, mainly the skin, bone, and lymph node. They are often associated with acute myeloid leukemia (AML) with monoblastic or myelomonocytic differentiation, including either AML M2 with t(8;21)(q22;q22) or AML M4Eo with inv(16)(p13q22). We present a case diagnosed with GS associated with AML M4 that presented a normal karyotype with conventional cytogenetic analysis. Although the myeloblasts did not show the inv(16)(p13q22) (CBFB/MYH11), a gain of multiple copies of the CBFB gene was detected with fluorescence in situ hybridization analysis. To our knowledge, no cases with this rare genetic anomaly have been previously described.  相似文献   
13.
Mutations in the voltage-gated chloride/proton antiporter ClC-5 gene, CLCN5, are associated with Dent’s disease, an X-linked renal tubulopathy. Our interest is to identify and characterize disease-causing CLCN5 mutations, especially those that alter the splicing of the pre-mRNA. We analyzed the CLCN5 gene from nine unrelated Spanish Dent’s disease patients and their relatives by DNA sequencing. Pre-mRNA splicing analysis was performed by RT-PCR. Seven new mutations were identified, consisting of three missense mutations (C219R, F273L, and W547G), one splice-site mutation (IVS-2A > G), one deletion (976delG), and two non-sense mutations (Y140X and W314X). We found that missense mutation W547G also led to increased expression of a new alternative isoform lacking exons 10 and 11 that was expressed in several human tissues. In addition, we describe another novel CLCN5 splicing variant lacking exon 11 alone, which was expressed only in human skeletal muscle. We conclude that missense mutation W547G can also alter the expression levels of a CLCN5 mRNA splicing variant. This type of mutation has not been previously described in the CLCN5 gene. Our results support the importance of a routine analysis at the pre-mRNA level of mutations that are commonly assumed to cause single amino acids alterations.  相似文献   
14.
15.
Species of the Metastrongylus genus, the lung nematodes of pigs that require an intermediate host (earthworm) to complete their cycle, pose a potential risk to both livestock and humans. This parasite which can result in lung pathology and mixed infections with other pathogens (e.g. viruses) can be fatal to pigs. Although this genus is distributed worldwide, there are no classification keys for identifying this common parasite species. In this work, we take advantage of parasitological surveys of wild boar (Sus scrofa) in northern and central Spain and southern Poland to develop a morphological identification key for the five most common Metastrongylus species (Metastrongylus apri, Metastrongylus pudendotectus, Metastrongylus salmi, Metastrongylus confusus and Metastrongylus asymetricus). In addition, we provide the first record of M. confusus in Spain, probably unidentified until now due to the lack of appropriate identification keys. We hope that this user-friendly identification key will enable parasitologists and veterinary practitioners to avoid further misclassifications of Metastrongylus species.  相似文献   
16.
Epitope Context and Reshaping of Activated T Helper Cell Repertoire   总被引:1,自引:0,他引:1  
In recent years, a growing interest in the study of peptide antigenicity in relation to the role of flanking sequences and protein topology in processing, presentation, and recognition has been observed. However, the information available on the antigenicity of recombinant fusion proteins and their effect on the selection of antigen receptor repertoires is limited. To analyze the role of molecular topology of T epitopes in a system relevant to human pathology, we have used the bacterially expressed Schistosoma japonicum glutathione S transferase (GST) to construct recombinant antigens containing HIV-1 derived T cell determinants, and human T cell clones specific for these determinants. We found that antigenicity of a given GST—peptide combination was not the same when T cells and antigen presenting cells from different individuals were tested. Our results show that differences in processing and presentation of chimeric proteins are not dictated by the use of diverse restriction elements. We also found that the context in which an antigenic peptide is delivered affects the recruited repertoire as defined according to T cell receptor Vβ usage and fine specificities of selected T cells.  相似文献   
17.
Heterozygous mutations in PMS2 are involved in Lynch syndrome, whereas biallelic mutations are found in Constitutional mismatch repair‐deficiency syndrome patients. Mutation detection is complicated by the occurrence of sequence exchange events between the duplicated regions of PMS2 and PMS2CL. We investigated the frequency of such events with a nonspecific polymerase chain reaction (PCR) strategy, coamplifying both PMS2 and PMS2CL sequences. This allowed us to score ratios between gene and pseudogene‐specific nucleotides at 29 PSV sites from exon 11 to the end of the gene. We found sequence transfer at all investigated PSVs from intron 12 to the 3′ end of the gene in 4 to 52% of DNA samples. Overall, sequence exchange between PMS2 and PMS2CL was observed in 69% (83/120) of individuals. We demonstrate that mutation scanning with PMS2‐specific PCR primers and MLPA probes, designed on PSVs, in the 3′ duplicated region is unreliable, and present an RNA‐based mutation detection strategy to improve reliability. Using this strategy, we found 19 different putative pathogenic PMS2 mutations. Four of these (21%) are lying in the region with frequent sequence transfer and are missed or called incorrectly as homozygous with several PSV‐based mutation detection methods. Hum Mutat 31:578–587, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   
18.
19.
Perinatal mortality and the incidence of neurological sequelae in preterm infants have diminished owing to advances in perinatology. The accurate assessment of gestational age is a very important component of the medical practice and for the newborn's management. Herein we provide a study to evaluate the neurological examination in comparison to the obstetrics dating criteria and pediatrics scales (Dubowitz and Capurro) to determine the gestational age as well as to compare the gestational age obtained with the different methods. We studied 35 preterm newborns leaving out those ones with any pathologies. The different scales to determine the gestational age were administered to each infant, beyond the neurological examination. We conclude that André-Thomas method is an appropriate clinical tool for reliable determining for gestational age in preterm newborns.  相似文献   
20.
Purpose To evaluate the cosmetic outcome of breast conservative therapy and to examine the degree of agreement between the patients’ and oncologists’ ratings. We also analyze the influence of several factors on cosmesis. Methods and materials We retrospectively evaluated 145 patients with primary breast cancer treated by local excision and radiotherapy between January 2000 and May 2001. Cosmetic outcome was evaluated by doctors and patients and was scored as excellent, good, fair or poor. Results 73% of patients rated cosmesis as excellent or good while the percentage was 71% when rated by radiation oncologists. The degree of cosmesis concordance evaluated by oncologists and patients was low (kappa=0.3). In our study the variables which significantly influence on the cosmetic outcome were concomitant adjuvant chemotherapy (p=0.04) and radiation therapy boost, either by electron beam or brachytherapy (p=0.013). Conclusion The cosmetic outcome of breast conserving therapy was good. There was a similar rating by the patient and radiation oncologist, but the level of concordance between patients and doctors was low. Factors that significantly influence the cosmesis appear to be concomitant adjuvant chemotherapy and radiation therapy boost.  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