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   2191篇
  免费   143篇
  国内免费   2篇
耳鼻咽喉   60篇
儿科学   79篇
妇产科学   46篇
基础医学   284篇
口腔科学   37篇
临床医学   172篇
内科学   565篇
皮肤病学   52篇
神经病学   129篇
特种医学   168篇
外科学   225篇
综合类   21篇
预防医学   169篇
眼科学   70篇
药学   104篇
中国医学   7篇
肿瘤学   148篇
  2023年   6篇
  2022年   15篇
  2021年   52篇
  2020年   21篇
  2019年   56篇
  2018年   56篇
  2017年   46篇
  2016年   41篇
  2015年   46篇
  2014年   63篇
  2013年   108篇
  2012年   107篇
  2011年   108篇
  2010年   81篇
  2009年   84篇
  2008年   93篇
  2007年   102篇
  2006年   99篇
  2005年   102篇
  2004年   97篇
  2003年   100篇
  2002年   75篇
  2001年   82篇
  2000年   93篇
  1999年   74篇
  1998年   42篇
  1997年   41篇
  1996年   41篇
  1995年   29篇
  1994年   34篇
  1993年   26篇
  1992年   25篇
  1991年   24篇
  1990年   13篇
  1989年   30篇
  1988年   30篇
  1987年   26篇
  1986年   27篇
  1985年   20篇
  1984年   11篇
  1983年   10篇
  1982年   8篇
  1981年   10篇
  1980年   5篇
  1979年   9篇
  1978年   9篇
  1977年   17篇
  1976年   9篇
  1975年   10篇
  1968年   4篇
排序方式: 共有2336条查询结果,搜索用时 296 毫秒
41.
PURPOSE: To evaluate the efficacy of reduced intensity conditioning (RIC) allogeneic transplant in 30 patients with poor-prognosis chronic lymphocytic leukemia (CLL) and/or high-risk molecular/cytogenetic characteristics. EXPERIMENTAL DESIGN: Eighty-three percent of patients had active disease at the moment of transplant. That is, 14 of the 23 patients analyzed (60%) had unmutated immunoglobulin variable heavy-chain gene (IgV(H)) status; 8 of 25 patients (32%) had 11q-, with four of them also displaying unmutated IgV(H); and six (24%) had 17p- (five were also unmutated). RESULTS: After a median follow-up of 47.3 months, all 22 patients alive are disease free; overall survival and event-free survival (EFS) at 6 years were 70% and 72%, respectively. According to molecular/cytogenetic characteristics, overall survival and EFS for unmutated CLL and/or with 11q- aberration (n = 13) were 90% and 92%, respectively, not significantly different to those with normal in situ hybridization, 13q- and +12, or mutated CLL (n = 7). All six patients with 17p deletion were transplanted with active disease, including three with refractory disease; all except one reached complete remission after the transplant and two are alive and disease free. Nonrelapse mortality (NRM) was 20%; more than two lines before transplant is an independent prognostic factor for NRM (P = 0,02), EFS (P = 0.02), and overall survival (P = 0.01). Patients older than 55 years have a higher risk of NRM (hazard ratio, 12.8; 95% confidence interval, 1.5-111). Minimal residual disease was monitored by multiparametric flow cytometry in 21 patients. Clearance of CD79/CD5/CD19/CD23 cells in bone marrow was achieved in 68% and 94% of the patients at days 100 and 360, respectively. CONCLUSION: According to these results, RIC allogeneic transplant could overcome the adverse prognosis of patients with unmutated CLL as well as those with 11q- or 17p-.  相似文献   
42.
In 1967, infants and toddlers immunized with a formalin-inactivated vaccine against respiratory syncytial virus (RSV) experienced an enhanced form of RSV disease characterized by high fever, bronchopneumonia, and wheezing when they became infected with wild-type virus in the community. Hospitalizations were frequent, and two immunized toddlers died upon infection with wild-type RSV. The enhanced disease was initially characterized as a “peribronchiolar monocytic infiltration with some excess in eosinophils.” Decades of research defined enhanced RSV disease (ERD) as the result of immunization with antigens not processed in the cytoplasm, resulting in a nonprotective antibody response and CD4+ T helper priming in the absence of cytotoxic T lymphocytes. This response to vaccination led to a pathogenic Th2 memory response with eosinophil and immune complex deposition in the lungs after RSV infection. In recent years, the field of RSV experienced significant changes. Numerous vaccine candidates with novel designs and formulations are approaching clinical trials, defying our previous understanding of favorable parameters for ERD. This review provides a succinct analysis of these parameters and explores criteria for assessing the risk of ERD in new vaccine candidates.  相似文献   
43.
44.
Cri du chat syndrome is an autosomal disorder. Because it affects few people in the population it is considered a rare disease, yet it is one of the most common autosomal chromosomal syndromes in humans. It entails pathognomonic alterations that affect the craniofacial and oral anatomy of patients. The aim of this study is to review these craniofacial and oral abnormalities in patients with Cri du chat syndrome. The PubMed Medline database was searched using two different strategies. First, we used “Dentistry” and “Cri du chat” as keywords; second, we used “Cri du chat” and “craniofacial.” Seven articles in which the main orofacial and cranio‐skeletal characteristics of patients with Cri du chat syndrome were described were selected according to the inclusion and exclusion criteria. Cri du Chat syndrome entails pathognomonic characteristics in the craniofacial area (epicanthus, short philtrum, and wide nasal bridge), the oral area (mandibular retrognathism and anterior open bite) and the cranial region (alterations at the cranial base angle and a small upper airway). However, more studies on larger samples are needed to specify the orofacial and craniofacial characteristics of patients with Cri du chat syndrome more accurately. Clin. Anat. 29:555–560, 2016. © 2015 Wiley Periodicals, Inc.  相似文献   
45.
ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tcr) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).ResultsPCR analysis indicated that Tcr E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.  相似文献   
46.
47.
fMRI studies of brain activity at rest study slow (<0.1 Hz) intrinsic fluctuations in the blood‐oxygenation‐level‐dependent (BOLD) signal that are observed in a temporal scale of several minutes. The origin of these fluctuations is not clear but has previously been associated with slow changes in rhythmic neuronal activity resulting from changes in cortical excitability or neuronal synchronization. In this work, we show that individual spontaneous BOLD events occur during rest, in addition to slow fluctuations. Individual spontaneous BOLD events were identified by deconvolving the hemodynamic impulse response function for each time point in the fMRI time series, thus requiring no information on timing or a‐priori spatial information of events. The patterns of activation detected were related to the motor, visual, default‐mode, and dorsal attention networks. The correspondence between spontaneous events and slow fluctuations in these networks was assessed using a sliding window, seed‐correlation analysis, where seed regions were selected based on the individual spontaneous event BOLD activity maps. We showed that the correlation varied considerably over time, peaking at the time of spontaneous events in these networks. By regressing spontaneous events out of the fMRI signal, we showed that both the correlation strength and the power in spectral frequencies <0.1 Hz decreased, indicating that spontaneous activation events contribute to low‐frequency fluctuations observed in resting state networks with fMRI. This work provides new insights into the origin of signals detected in fMRI studies of functional connectivity. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
48.
Biomarkers useful for the evaluation and management of patients with chronic spontaneous urticaria (CSU) are not currently available. A review of various clinical and laboratory markers that have been studied to assess their value for determining the severity or predicting the evolution of disease in adult patients with CSU was carried out. A search of the medical literature on PubMed and MEDLINE including the terms urticaria, chronic urticaria, chronic idiopathic urticaria, CSU, severity, prognosis and treatment was performed. Based on our review of the literature, among the clinical markers studied, higher age at onset, being female, long disease duration and aspirin/NSAID hypersensitivity may be linked to both severe CSU and a long time to spontaneous remission. In addition, a positive autologous serum skin test (ASST) may be associated with severe CSU, and comorbidity of inducible urticaria and concomitant recurrent angio‐oedema may be linked to longer CSU duration. Potential biomarkers of CSU severity and/or duration include basophil numbers and susceptibility to activation, inflammatory markers, markers of activation of the extrinsic coagulation pathway, immunoglobulin E and vitamin D. Although the described markers are promising, further studies on representative and well‐characterized patient populations are needed to determine the value of these clinical and biological markers for predicting the severity and course of disease in patients with CSU.  相似文献   
49.
50.
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