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   10528篇
  免费   605篇
  国内免费   52篇
耳鼻咽喉   103篇
儿科学   220篇
妇产科学   137篇
基础医学   1757篇
口腔科学   120篇
临床医学   975篇
内科学   2453篇
皮肤病学   273篇
神经病学   1144篇
特种医学   620篇
外科学   1642篇
综合类   77篇
一般理论   2篇
预防医学   373篇
眼科学   173篇
药学   547篇
中国医学   7篇
肿瘤学   562篇
  2023年   67篇
  2022年   115篇
  2021年   212篇
  2020年   132篇
  2019年   186篇
  2018年   207篇
  2017年   205篇
  2016年   264篇
  2015年   284篇
  2014年   323篇
  2013年   384篇
  2012年   640篇
  2011年   734篇
  2010年   447篇
  2009年   434篇
  2008年   654篇
  2007年   673篇
  2006年   598篇
  2005年   658篇
  2004年   633篇
  2003年   582篇
  2002年   598篇
  2001年   111篇
  2000年   120篇
  1999年   144篇
  1998年   152篇
  1997年   131篇
  1996年   105篇
  1995年   89篇
  1994年   65篇
  1993年   76篇
  1992年   65篇
  1991年   61篇
  1990年   44篇
  1989年   43篇
  1988年   48篇
  1987年   32篇
  1986年   31篇
  1985年   48篇
  1984年   33篇
  1983年   34篇
  1982年   28篇
  1981年   25篇
  1979年   20篇
  1978年   22篇
  1977年   23篇
  1976年   18篇
  1974年   19篇
  1971年   24篇
  1931年   18篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
1.
2.
3.
4.
We aimed to evaluate the potential of the cerebrospinal fluid (CSF) axonal damage biomarker NfH(SMI35) in the laboratory-supported differential diagnosis of parkinsonian syndromes. Patients with idiopathic Parkinson's disease (PD; n = 22), multiple-system atrophy (MSA; n = 21), progressive supranuclear palsy (PSP; n = 21), corticobasal degeneration (CBD; n = 6), and age-matched controls (n = 45) were included. CSF levels of NfH(SMI35) were measured using ELISA. Levels of CSF NfH(SMI35) were elevated in PSP compared to PD and controls (P < 0.05 each). They were also significantly higher in MSA than in PD and controls (P < 0.05 each). NfH(SMI35) differentiated PD from PSP with a sensitivity of 76.5% and a specificity of 94.4%. Axonal damage as measured by CSF NfH(SMI35) is most prominent in the more rapidly progressive syndromes PSP and MSA as compared to PD or CBD. CSF NfH(SMI35) may therefore be of some value for the laboratory-supported differential diagnosis of atypical parkinsonian syndromes.  相似文献   
5.
Intramedullary nailing implants have now assumed the first place in the treatment of pertrochanteric fractures.The reasons for their popularity are their high fatigue strength and the minimally invasive surgical technique required for their use.These advantages are of great benefit to the mainly geriatric and frequently multitraumatized patients concerned.The main device in this implant group is the gamma nail, which was originally developed by Grosse and Kempf. The gamma nail yielded results superior to those obtained with the dynamic hip screw, which had been the standard so far, especially when it was used in the treatment of unstable fractures.Although there was some vigorous debate over the original principles of the gamma nail, the current system is widely accepted and is available in different variants.However,owing to the high complication rate when the system was first introduced, the original gamma nail acquired the reputation of being an implant whose use made high demands.The critical analysis of implant-specific problems associated with the original gamma nail resulted in improvements to the implant and the instruments, with a noticeably reduced complication rate and better surgical technique.This article describes its current state of development.The various components are discussed individually. The results of our own investigation appear at the end of the report, reflecting this development process.  相似文献   
6.
7.
Maximum anchorage often presents a problem that is difficult to solve during orthodontic tooth movement. Stationary, skeletal anchorage can be achieved in a simple, minimally-invasive manner, and unwanted tooth movements in opposite directions can be prevented by using transmucosally-inserted bone screws.Our initial experience using the FAMI screw as an orthodontic micro-implant proved to be clinically and histologically successful.  相似文献   
8.
9.
Fragestellung: Die Karzinomassoziierte Retinopathie (CAR) stellt ein seltenes paraneoplastisches Syndrom dar, das bislang am h?ufigsten bei kleinzelligen Bronchialkarzinomen beschrieben wurde. Wir berichten über 3 Patientinnen mit CAR in Gegenwart eines Mammakarzinoms bzw. eines Karzinoids der Cervix uteri. Patienten und Methode: Es wurden biomikroskopische, perimetrische, angiographische und elektrophysiologische Befunde erhoben. Au?erdem erfolgte eine Testung der Immunreaktivit?t der Seren an humaner Retina. Ergebnisse: Die Befunde umfa?ten ringf?rmige Gesichtsfelddefekte mit statokinetischer Dissoziation und eine pathologische St?bchen- und Zapfenantwort im ERG. Bei 1 Patientin wurde immunhistochemisch eine Reaktion im Bereich der Photorezeptorinnensegmente, der ?u?eren K?rnerschicht sowie der ?u?eren plexiformen Schicht bei fehlendem Nachweis von Antik?rpern gegen Recoverin gefunden. Diskussion: Neben dem kleinzelligen Bronchialkarzinom k?nnen auch andere Prim?rtumoren mit einer CAR vergesellschaftet sein. Der Nachweis von retinalen Autoantik?rpern unterstützt die Annahme einer tumorinduzierten Immunantwort aufgrund der Expression identischer Epitope durch die Tumorzellen. Dabei kommen offensichtlich verschiedene retinale Proteine als Autoantigene in Betracht.   相似文献   
10.
Abstract: The galactoside-specific plant lectin, Viscum album agglutinin (VAA-I) increases cellular parameters of natural host defence. It also binds to a variety of haematopoietic cells, including progenitors. We investigated whether VAA-I has a stimulatory effect on haematopoietic progenitor cells. Peripheral blood progenitor cells from 7 healthy volunteers were cultured in a colony assay with VAA-I plus erythropoietin (EPO) and stem cell factor (SCF). At 50 pg/ml VAA-I induced a significant increase in the cytokine-dependent clonogenic growth (52% in median, p<0.05). In another set of experiments purified CD34+ cells were isolated from the bone marrow aspirate of 4 patients with non-metastatic breast cancer using fluorescence-activated cell sorting. Binding to CD34+ cells was demonstrated by using directly fluorescence-conjugated VAA-I. Co-incubation with d -galactose significantly abrogated this effect. CD34+ cells were cultured in the presence of EPO, SCF, interleukin-3, granulocyte/monocyte colony-stimulating factor and granulocyte colony-stimulating factor. VAA-I alone had no measurable effect on the clonogenic growth of the isolated cells. However, at concentrations of 100 and 250 pg/ml VAA-I increased the cytokine-dependent proliferation and differentiation of CD34+ cells by a median of 75 and 85%, respectively. The results show that VAA-I binds to haematopoietic progenitor cells and has a co-stimulatory effect on their proliferation.  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