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   1161篇
  免费   66篇
  国内免费   28篇
耳鼻咽喉   1篇
儿科学   41篇
妇产科学   22篇
基础医学   167篇
口腔科学   17篇
临床医学   86篇
内科学   184篇
皮肤病学   22篇
神经病学   20篇
特种医学   160篇
外科学   96篇
综合类   126篇
预防医学   66篇
眼科学   79篇
药学   72篇
  1篇
肿瘤学   95篇
  2023年   7篇
  2022年   3篇
  2021年   18篇
  2020年   5篇
  2019年   13篇
  2018年   15篇
  2017年   15篇
  2016年   9篇
  2015年   22篇
  2014年   23篇
  2013年   41篇
  2012年   45篇
  2011年   48篇
  2010年   41篇
  2009年   50篇
  2008年   58篇
  2007年   60篇
  2006年   49篇
  2005年   31篇
  2004年   29篇
  2003年   24篇
  2002年   27篇
  2001年   28篇
  2000年   43篇
  1999年   35篇
  1998年   44篇
  1997年   49篇
  1996年   45篇
  1995年   26篇
  1994年   25篇
  1993年   26篇
  1992年   15篇
  1991年   15篇
  1990年   19篇
  1989年   29篇
  1988年   26篇
  1987年   19篇
  1986年   29篇
  1985年   19篇
  1984年   10篇
  1983年   6篇
  1982年   18篇
  1981年   16篇
  1980年   12篇
  1979年   5篇
  1978年   10篇
  1977年   12篇
  1976年   11篇
  1975年   10篇
  1973年   4篇
排序方式: 共有1255条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: We have seen several patients with itchy lichenified plaques located bilaterally on the elbows and/or knees and have named this condition 'psoriatic neurodermatitis' (PN). OBJECTIVE: The purpose of this study was to compare clinical and histopathological characteristics of these patients to those of patients with typical lichen simplex chronicus (LSC). METHODS: Nineteen patients with PN and 34 patients with typical LSC were included. Besides clinical dermatological evaluation, the prick test was carried out on 49 patients; the Phadiatop test on 40 patients; the patch test with European standard series on 47 patients; histopathological evaluation on 39 patients; and clinical psychiatric examination on 38 patients. RESULTS: Almost exclusively, PN was seen in females and was located on the extremities. It caused more plaques than typical LSC did. In PN, the plaques were smaller, sharper, more keratotic and less excoriated, and had fewer lichenoid papules around them. Itching was usually more severe in the evening, while resting and in a hot environment in typical LSC, but not in PN. In plaques of PN, microabscesses in the horny layer, hypogranulosis, regular acanthosis and thinning of the suprapapillary plates were more frequent, and hyperpigmentation in the basal layer was less. In patients with PN, depressive disorder was found more frequently; and generalized anxiety disorder or psychosomatic characteristics, less. There were no significant differences in the results of prick, Phadiatop and patch tests between patients with PN and those with typical LSC. CONCLUSION: In our opinion, it is most likely that the so-called PN is itchy psoriasis superimposed by LSC.  相似文献   
2.
3.
In this study intact and suprachiasmatic nuclei (SCN)-lesioned female rats were treated with chronic methamphetamine (MA) via the drinking water. Body temperature, feeding, drinking and wheel-running activity were continuously and automatically recorded. The rats were subjected to light-dark (LD) cycles with period T = 23 hr for 4 months and subsequently T = 25 hr for 3 months. Daily 3-hr forced activity (FA 3:21) was imposed during a few weeks under both LD regimes. MA induced infradian rhythms (period tau s = 28-54 hr) that were found to run parallel in all functions. In intact rats these infradian rhythms showed relative coordination by the LD regime and tau s shortened when T lengthened. In SCN-lesioned rats, however, the infradian rhythms were independent of the LD regime. Under the FA cycles tau s lengthening as well as synchronization was observed. We hypothesized that the MA-induced rhythms reflect a long-period sleep-wake cycle of the hourglass type. We investigated this hypothesis with a modified version of the hourglass-clock model of sleep regulation. Computer simulations showed that this model might offer an explanation for the experimental observations.  相似文献   
4.
5.
6.
A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.  相似文献   
7.
Hemopoietic stem cell transplantation in rheumatic diseases--an update   总被引:2,自引:0,他引:2  
Hematopoietic stem cell transplant (HSCT) for autoimmune diseases has been recognized as a potential treatment for patients who have failed conventional therapy. Autologous (self) donor cells have been preferred over allogeneic (HLA-matched) cells for rescue after high dose immunotherapy, given the previous higher rates of mortality, graft versus host disease (GVHD), and the need for more intense myeloablation associated with the latter. The European Group for bone Marrow Transplantation in Basel Switzerland (EBMT) and various groups within the US funded by the NIH (including the Autologous Blood and Marrow Transplant Registry (ABMTR)) have been pivotal in maintaining registries on patients transplanted as well as promoting homogeneity for future studies including Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE) and Systemic Sclerosis (SSc). Although, patients transplanted for RA show initial success, relapse of the disease is common. In many, however, a second positive result can be obtained with the addition of DMARD therapy to which they were previously unresponsive, suggesting a "debulking" of disease by HSCT. SLE patients also have a high rate of success after HSCT, although current mortality rates appear high. Transplant in SSc patients has offered durable responses with improving transplant-related mortality related to careful patient selection.  相似文献   
8.
Duchenne and Becker muscular dystrophy (DMD and BMD) are caused by mutations in the dystrophin gene. Large rearrangements in the gene are found in about two-thirds of DMD patients, with approximately 60% carrying deletions and 5-10% carrying duplications. Most of the remaining 30-35% of patients are expected to have small nucleotide substitutions, insertions, or deletions. To detect these subtle changes within the coding and splice site determining sequences of the dystrophin gene, we established a semiautomated denaturing gradient gel electrophoresis (DGGE) mutation scanning system. The DGGE scan covers the dystrophin gene with 95 amplicons, PCRed either individually or in a multiplex setup. PCR and pooling were performed semiautomatically, using a pipetting robot and 384-well plates, enabling concurrent amplification of DNA of four patients in one run. Amplification of individual fragments was performed using one PCR program. The products were pooled just before gel loading; DGGE requires only a single gel condition. Validation was performed using DNA samples harboring 39 known DMD variants, all of which could be readily detected. DGGE mutation scanning was applied to analyze 135 DMD/BMD patients and potential DMD carriers without large deletions or duplications. In DNA from 25 out of 44 DMD patients (57%) and from 5 out of 39 BMD patients (13%), we identified clear pathogenic changes. All mutations were different, with the exception of one DMD mutation, which occurred twice. In DNA from 10 out of 44 potential DMD carriers, including four obligate carriers, we detected causative changes, including one pathogenic change in every obligate carrier. In addition to these pathogenic changes, we detected 15 unique unclassified variants, i.e., changes for which a pathogenic nature is uncertain.  相似文献   
9.
The aim of this paper is twofold. Firstly, to investigate the potential benefits of online health communities (OHCs) for informal caregivers by conducting a systematic literature review. Secondly, to identify the relationship between the potential benefits of OHCs and resilience factors of older adults. Performing a thematic analysis, we identified the potential benefits of OHCs for informal caregivers of older adults, including two salient themes: (a) caregivers sharing and receiving social support and (b) self and moral empowerment of caregivers. Then, we uncovered how these potential benefits can support resilience of older adults. Our findings show that sharing and receiving of social support by informal caregivers, and self and moral empowerment of informal caregivers in OHCs, can support four resilience factors among older adults, including self-care, independence, altruism and external connections. This review enables a better understanding of OHCs and Gerontology, and our outcomes also challenge the way healthcare and aged-care service providers view caregivers and older adults. Furthermore, the identified gap and opportunities would provide avenues for further research in OHCs.  相似文献   
10.
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