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   1097篇
  免费   73篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   16篇
妇产科学   16篇
基础医学   231篇
口腔科学   4篇
临床医学   77篇
内科学   261篇
皮肤病学   21篇
神经病学   111篇
特种医学   20篇
外科学   65篇
综合类   8篇
预防医学   57篇
眼科学   19篇
药学   159篇
中国医学   6篇
肿瘤学   96篇
  2024年   1篇
  2023年   5篇
  2022年   21篇
  2021年   44篇
  2020年   29篇
  2019年   33篇
  2018年   39篇
  2017年   33篇
  2016年   55篇
  2015年   39篇
  2014年   53篇
  2013年   63篇
  2012年   107篇
  2011年   117篇
  2010年   58篇
  2009年   56篇
  2008年   72篇
  2007年   65篇
  2006年   49篇
  2005年   62篇
  2004年   57篇
  2003年   41篇
  2002年   31篇
  2001年   5篇
  2000年   2篇
  1999年   3篇
  1998年   6篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   3篇
  1992年   7篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1986年   2篇
  1985年   2篇
  1981年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有1173条查询结果,搜索用时 62 毫秒
111.
112.
In vitro labeling of pancreatic islets with iron nanoparticles enables their direct posttransplant visualization by magnetic resonance; however, there is still a discrepancy in the fate of iron nanoparticles. This study was performed to detail the labeling process, consequently to improve the labeling efficacy and to confirm safety for islet cells. The islets were visible on T2*-weighted magnetic resonance images as hypointense spots immediately after 1-hr cultivation. Although at this time already the sufficient superparamagnetic effect was achieved, most of the particles were deposed in islet macrophages and only later were they found in endosomes of endocrine islet cells. The iron content depended on length of culture period. The labeled islets showed an intact ultrastructure, responded normally to glucose stimulation in vitro, and were able to treat experimental diabetes. For purpose of subsequent magnetic resonance imaging, a 24-hr culture with ferucarbotran leads to sufficient labeling with no apparent adverse effect on beta cell morphology or function.  相似文献   
113.
We compared the effect of control genes (CG): total Abelson (total-ABL), beta-2-microglobulin (B2M) and beta-glucuronidase (GUS), recommended in the Europe Against Cancer (EAC) program, on real-time BCR-ABL monitoring in patients with chronic myeloid leukemia (CML). We focused on the stability of CG expressions during therapy and the effect of the CGs on BCR-ABL ability to characterize the disease status and disease prognosis, issues that have not been addressed yet. The results showed B2M as a very convenient CG for BCR-ABL monitoring. On the contrary, the widely used total-ABL was not confirmed as appropriate for normalization of gene expression in CML.  相似文献   
114.
Specific gene mutations, loss of heterozygosity, deletions and/or amplifications of entire chromosomal regions and gene silencing have been described in gliomas. 82 samples from 81 patients were investigated to detect the deletion of TP53, RB1, CDKN2A genes, deletion of 1p36 and 19q13.3 region, amplification of EGFR gene, trisomy of chromosome 7 and monosomy of chromosome 10 in glial cells. Dual-colour interphase fluorescence in situ hybridization (I-FISH) with locus-specific and/or chromosome enumeration DNA probes were used for cytogenetic analyses. In the study, molecular cytogenetic analyses were successfully performed in 74 patients (91.3%) and were uninformative in 7 only (8.7%). The cytogenetic analyses were correlated with morphological data and clinical outcome. I-FISH was the essential part of diagnostics. In comparison with the clinical data, the patients’ age seems to be a factor more important for the overall survival, rather than cytogenetic findings in glial tumours. The combined deletion of 1p36 and 19q13.3 chromosomal regions predicts longer overall survival for patients with oligodendroglial tumours.  相似文献   
115.
This review of literature gives an overview of recent studies about perceived health status as measured by the Short-Form-36 (SF-36) Health Survey in patients with multiple sclerosis (MS). The SF-36 is one of the tools measuring health status in patients used in international research and clinical practice. It measures two main health concepts – physical and mental. The SF-36 represents a valid instrument able to detect differences in perceived health status in patients. A computer-aided search in Medline and PsycINFO resulted in 504 articles in English published from 1996 to August 2006. After the screening process on the basis of abstracts, eight articles consisting of empirical studies remained in which perceived health status was evaluated using the SF-36 Health Survey. Seven studies focused on disability and perceived health status in the SF-36. Two studies focused on the relationship between depression and perceived health status. These studies showed that MS patients with low disability and minor depression scored significantly better than patients with high disability and major depression in the SF-36 health dimensions. Gender seems to have no influence on perceived health status in MS patients. The longer the disease duration and the more severe the disease, the lower the patients scored in perceived health status. The more disabled, the more depressive and the older the patients, the poorer their perceived health status was. Health providers supporting appropriate treatment might pay more attention to more disabled and more depressive patients, with longer disease duration. Perceived health status can be a predictor of prognosis and intervention outcomes. The study shows the importance of measuring perceived health status in MS patients with implications for their quality of life and provision of care.  相似文献   
116.
117.
Objectives: Patients with near‐tetraploid (karyotype: 81 – 103 chromosomes) acute lymphoblastic leukemia (NT‐ALL) constitute about 1% of childhood ALL and data reported on them are limited and controversial. The aim of the study was to enlarge the knowledge on these rarely occurring ALL. Methods: The members of the European Group for Immunophenotyping of Leukemias (EGIL) searched retrospectively their databases for NT‐ALL patients. Results: We collected data of 36 European children from seven European countries with NT‐ALL diagnosed since 1992. All patients reached complete remission (CR) after induction chemotherapy. Their blasts were negative for peroxidase and BCR‐ABL1. Ten children were diagnosed as T‐cell ALL (T‐ALL) EGIL categories (T‐I n = 2, T‐II n = 2, T‐III n = 3, T‐IV n = 3) and four displayed various structural chromosomal abnormalities. Eight of 10 T‐ALL remained in 1st CR; one died in CR from sepsis and one is alive in 2nd CR. Median survival was 88 (7–213) months. B‐cell precursor (BCP) ALL was diagnosed in 26 children. Thirteen were positive for ETV6‐RUNX1 and are alive in 1st CR for 32–147 months. Ten children were ETV6‐RUNX1 negative and remained in 1st CR for 16–163 months. One girl with hypodiploid and NT metaphases and ETV6‐RUNX1‐negative BCP‐ALL and one of two boys with NT‐BCP‐ALL not examined for ETV6‐RUNX1 died of infection after stem cell transplantation in 2nd/3rd CR. Secondary myelodysplastic syndrome developed in two patients with NT‐BCP‐ALL. Conclusions: Our data demonstrate immunophenotypic, cytogenetic, and molecular heterogeneity of NT‐ALL and favorable prognosis of most NT‐ALL across different immunophenotypic and/or genetic ALL subtypes.  相似文献   
118.
The shape of the conversion curves and the rates of the emulsion polymerization in batch of methyl methacrylate (MMA) in the presence of seed particles of poly(butyl acrylate) (PBA) depend on the mass ratio of methyl methacrylate/poly(butyl acrylate) MMA/PBA and on the presence or absence of 2,2,6,6-tetramethyl-4-octadecanoyloxypiperidinyl-1-oxyl (STMPO). Irrespective of the presence and/or absence of STMPO in the reaction system, the diameter of a polumer particle experimentally found and calculated on the assumption that no new crop of polymer particles is formed, agrees well for systems with “low” (0,632) mass ratio of MMA/PBA. For systems with “high” (3,160) mass ratio of MMA/PBA, the calculated diameter is higher than that experimentally measured. This indicates that for “low” values of MMA/PBA, all poly(methyl methacrylate) formed was only used for building up shells of poly(butyl acrylate) particles. For “high” values of MMA/PBA, about 37 mass-% (in the absence of STMPO) or 57 mass-% (in the presence of STMPO) of poly(methyl methacrylate) formed was used for generating a crop of poly(methyl methacrylate) particles. Retardation of the polymerization rate in the presence of STMPO is more pronounced for systems characterized by a “low” value of the mass ratio MMA/PBA. Only short inhibition periods (up to five minutes) were observed for both “low” and “high” MMA/PBA ratios. It is shown that for the “low” mass ratio of MMA/PBA the “inner” monomer transport (from PBA particles swollen with MMA) to the locus of propagation is decisive. For systems with a “hugh” mass ratio MMA/PBA, the “outer” monomer transport from monomer droplets and micelles swollen by monomer to the locus of propagation is of primary importance. To explain the experimental results a reaction mechanism for the seeded emulsion polymerization is proposed.  相似文献   
119.
A set of 18 Y-chromosomal microsatellite loci was analysed in 568 males from Poland, Slovakia and three regions of Belarus. The results were compared to data available for 2,937 Y chromosome samples from 20 other Slavic populations. Lack of relationship between linguistic, geographic and historical relations between Slavic populations and Y-short tandem repeat (STR) haplotype distribution was observed. Two genetically distant groups of Slavic populations were revealed: one encompassing all Western-Slavic, Eastern-Slavic, and two Southern-Slavic populations, and one encompassing all remaining Southern Slavs. An analysis of molecular variance (AMOVA) based on Y-chromosomal STRs showed that the variation observed between the two population groups was 4.3%, and was higher than the level of genetic variance among populations within the groups (1.2%). Homogeneity of northern Slavic paternal lineages in Europe was shown to stretch from the Alps to the upper Volga and involve ethnicities speaking completely different branches of Slavic languages. The central position of the population of Ukraine in the network of insignificant AMOVA comparisons, and the lack of traces of significant contribution of ancient tribes inhabiting present-day Poland to the gene pool of Eastern and Southern Slavs, support hypothesis placing the earliest known homeland of Slavs in the middle Dnieper basin.  相似文献   
120.
Chronic pain is a debilitating condition with a multidimensional impact on the lives of patients, their families and communities. The public health burden of chronic pain is gathering recognition as a major healthcare problem in its own right and deserves closer attention. The challenge in treating chronic pain is to provide effective clinical management of a complex, multifaceted set of conditions that require a coordinated strategy of care. Epidemiological data and patient surveys have highlighted the areas of pain management that might be improved. These include a need for better understanding and documentation of the symptoms of chronic pain, standardized levels of care, improved communication among clinical personnel and with patients, and an updated education program for clinicians. For these reasons, new strategies aimed at improving the standards of pain management are needed. The Pain Associates' International Network (P.A.I.N.) Initiative was set up to devise practical methods for improving the quality of pain management for patients. These strategies have recently been put into practice through a number of activities: P.A.I.N. Workshops are meetings of international pain management professionals dedicated to discussing current management strategies and producing consensus recommendations for improving standards of care; P.A.I.N. Quality is a unique software program designed to help treating clinicians to document patient data and derive effective treatment plans; P.A.I.N. Online provides a web site forum for discussion of pain management topics; and P.A.I.N. Management is a clinician education program providing up‐to‐date training in pain management.  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