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   218篇
  免费   23篇
儿科学   7篇
妇产科学   3篇
基础医学   25篇
口腔科学   1篇
临床医学   14篇
内科学   63篇
皮肤病学   11篇
神经病学   25篇
特种医学   32篇
外科学   5篇
综合类   2篇
预防医学   21篇
眼科学   6篇
药学   17篇
肿瘤学   9篇
  2023年   5篇
  2022年   5篇
  2021年   11篇
  2020年   8篇
  2019年   4篇
  2018年   2篇
  2017年   5篇
  2016年   12篇
  2015年   6篇
  2014年   9篇
  2013年   9篇
  2012年   20篇
  2011年   18篇
  2010年   5篇
  2009年   6篇
  2008年   15篇
  2007年   15篇
  2006年   13篇
  2005年   11篇
  2004年   11篇
  2003年   12篇
  2002年   10篇
  2001年   6篇
  2000年   2篇
  1999年   5篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1993年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1982年   2篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
排序方式: 共有241条查询结果,搜索用时 12 毫秒
181.
Driver (sham-operated) and tester (ischemic) hippocampal cDNAs were subtracted, and the resulting ischemia-induced upregulated gene expression was verified by northern analysis. cDNAs isolated corresponded to (1) genes known to be upregulated following ischemia, (hsc70, hsp90, hsp105 and trkB) and (2) a gene not previously implicated with cerebral ischemia, sodium calcium exchanger (ncx). Furthermore, upregulation of these genes was demonstrated following preconditioning transient global ischemia.  相似文献   
182.
Systematic applications of ideas from equilibrium statistical mechanics lead to promising strategies for assessing the unresolved scales of motion in many problems in science and engineering. A scientific debate over more than the last 25 years involves which conserved quantities among the formally infinite list are statistically relevant for the large-scale equilibrium statistical behavior. Here this important issue is addressed by using suitable discrete numerical approximations for geophysical flows with many conserved quantities as a numerical laboratory. The results of numerical experiments are presented here for these truncated geophysical flows with topography in a suitable regime. These experiments establish that the integrated third power of potential vorticity besides the familiar constraints of energy, circulation, and enstrophy (the integrated second power) is statistically relevant in this regime for the coarse-grained equilibrium statistical behavior at large scales. Furthermore, the integrated higher powers of potential vorticity larger than three are statistically irrelevant for the large-scale equilibrium statistical behavior in the examples studied here.  相似文献   
183.
Essential oil from a few different population of M. officinalis cultivated in Poland has been investigated. The percentage of essential oil ranged from 0.08 to 0.25 ml/100 g in the leaves and from 0.06 to 0.167 ml/100 g in the herb and was higher in the plant material from experimental patch than that from commercial cultivations. Comparative determinations of the essential oil in fresh and dried material showed slightly higher content of the oil in the fresh one. The analysis of the oil composition has been performed by GC and GC/MS. Great differences in the contents of citral, citronellal, linalool, nerol, geraniol beta-caryophyllene and beta-caryophyllene oxide among the populations has been found. Effect of the harvest time, drying and storage on the composition of lemon balm oil has also been studied.  相似文献   
184.
The effect of nonspecific immunostimulation was examined in 15 basketball players subjected to extensive physical effort. The To?pa* Torf Preparation (TTP*), a natural immunostimulating drug, was applied orally, one 5 mg tablet daily, in two 21-day cycles, separated by 2-week hiatus. Blood samples were collected 4 times, after each of two TTP* cycles and after the first and second hiatus. Whole blood assay was used to determine the spontaneous and induced production of interferon (IFN) and tumor necrosis factor (TNF). The levels of the cytokines were measured by microbioassays. TTP* stimulated synthesis of IFN and TNF in the whole blood cultures. However, after the oral administraton of TTP* for 3 weeks the leukocytes of the athletes developed hyporeactivity to IFN induction by TTP* and to a lesser extent to another "superinducer"--a mixture of phytohemagglutinin and bacterial lipopolysaccharide. The hyporeactivity state disappeared spontaneously within 2 weeks. In contrast, the tolerance to TNF induction did not develop during the TTP* administration. The increase of immunoglobulins, mainly of IgM and IgG classes and an acute phase protein--alpha1-antitrypsin, was observed at the late phase of the treatment. We suggest that the cytokine levels may be early markers for immunoprophylaxis. Furthermore, high production of IFN and TNF may be associated with extensive physical effort.  相似文献   
185.
186.
Understanding and improving the predictive skill of imperfect models for complex systems in their response to external forcing is a crucial issue in diverse applications such as for example climate change science. Equilibrium statistical fidelity of the imperfect model on suitable coarse-grained variables is a necessary but not sufficient condition for this predictive skill, and elementary examples are given here demonstrating this. Here, with equilibrium statistical fidelity of the imperfect model, a direct link is developed between the predictive fidelity of specific test problems in the training phase where the perfect natural system is observed and the predictive skill for the forced response of the imperfect model by combining appropriate concepts from information theory with other concepts based on the fluctuation dissipation theorem. Here a suite of mathematically tractable models with nontrivial eddy diffusivity, variance, and intermittent non-Gaussian statistics mimicking crucial features of atmospheric tracers together with stochastically forced standard eddy diffusivity approximation with model error are utilized to illustrate this link.  相似文献   
187.
There are numerous dermatoses which may cause cicatricial alopecia when localized on the scalp, such as chronic discoid lupus erythematosus (DLE), lichen planus, graft-versus-host disease, dermatomyositis, scleroderma, cicatricial pemphigoid, porphyria cutanea tarda, follicular mucinosis, perifolliculitis capitis abscedens, lichen sclerosus et atrophicus, necrobiosis lipoidica, sarcoidosis, etc. Histologically, cicatricial alopecia is characterized by dermal scarring, along with absent or reduced hair follicles and reduced number of erector pili muscles. According to working classification of cicatricial alopecia by the North American Hair Society, primary cicatricial alopecia may be divided into the following categories: lymphocytic group (e.g., DLE, lichen planopilaris, classic pseudopelade (Brocq), central centrifugal cicatricial alopecia); neutrophilic group (e.g., folliculitis decalvans, dissecting cellulitis); and mixed group (e.g., folliculitis keloidalis). Over a 5-year period, 36 patients with cicatricial alopecia were hospitalized at our Department: DLE (n = 27), pseudopelade Brocq (n = 3), mucinosis follicularis (n = 2), and lichen planopilaris, folliculitis decalvans, folliculitis abscedens and folliculitis keloidalis (one patient each). Clinical evaluation was compared with histopathologic analysis of follicular architecture, as well as with the type, localization and extent of inflammatory infiltrate. Scalp biopsy was considered mandatory in all cases. Our experience indicates the need of more complex research to extend the knowledge about the etiopathogenesis and treatment options for cicatricial alopecia. We hope that this type of alopecia may attract more attention and research in the future.  相似文献   
188.
Vitiligo, depigmenting disorder of the skin and mucous membranes, affects up to 1% of the population worldwide. It is classified into four major types: segmental, non‐segmental, mixed, and unclassified type. Non‐segmental vitiligo refers to non‐dermatomal distribution of lesions, while dermatomal distribution of lesions is present in patients with segmental vitiligo. Segmental vitiligo can also follow Blaschko lines – pathways of epidermal cell migration and proliferation during the development of the fetus. Here, we present patient with segmental and non‐segmental vitiligo following Blaschko lines with excellent therapeutic response to combined therapy. Prior to our report, a case of segmental and non‐segmental vitiligo followed by Blaschko lines was never described, therefore we suggest the term “mixed vitiligo of Blaschko lines” to describe this entity. This is also a rare case in which 90% repigmentation was achieved in patient with segmental and nonsegmental vitiligo following Blaschko lines in only 2 months of combined therapy.  相似文献   
189.
BackgroundPatients with haemophilia A (HA) or B (HB) can be given prophylactic or on-demand treatment administered by continuous infusion or bolus injections of factor VIII (FVIII) or IX (FIX). In this study we evaluated the efficacy and safety of low-dose continuous infusion of FVIII or FIX.ResultsA total of 66 continuous infusions (40 in major surgery, 10 in minor surgery and 16 with bleeding episode) in 46 HA patients and 16 (15 in severe and 1 in mild HA) in eight HB patients were included in the study. During the first week of treatment, the median continuous infusion rates in HA patients undergoing major surgery, minor surgery and a bleeding event were 2.18 (0.75–3.68), 1.48 (1.0–2.54) and 2.24 (1.33–3.93) IU/kg/h, respectively. The median FVIII activities were 0.69 (0.37–1.19), 0.47 (0.39–0.84) and 0.52 (0.36–1.06) IU/mL. After the first week of treatment, even lower doses of FVIII were needed. Red blood cell transfusions had to be administered to three patients (2 with severe and 1 with moderate HA) during the continuous infusion and inhibitors developed in five patients. In HB patients, the median continuous infusion rate was 1.85 (1.07–2.94) IU/kg/h and the median FIX activity was 0.62 (0.30–1.04) IU/mL. Red blood cell transfusions were not required, and thrombophlebitis and inhibitors did not appear.DiscussionOverall, low-dose continuous infusion was shown to be an effective and safe way of treating patients with HA. The protocol used also proved efficient and safe in all HB patients.  相似文献   
190.
Different clinical studies report the connection between malignant melanoma (MM) and vitiligo, as the etiology of both diseases evolves around melanocytes. A case is presented of a 70-year-old female patient with metastatic MM in lymphatic node of the right groin, which developed simultaneously with the "vitiligo-like patches" over the face and extremities. Some authors suggest that the appearance of depigmentation during the course of MM might be considered a good prognostic sign. However, our patient subsequently developed multiple lung metastases as well as metastases in lymphatic nodes of the other groin region. This case shows that MM and vitiligo may develop simultaneously, indicating the possibility of similar mechanisms in the destruction of both benign and malignant melanocytes.  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