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   2381125篇
  免费   195353篇
  国内免费   4245篇
耳鼻咽喉   34339篇
儿科学   72895篇
妇产科学   62988篇
基础医学   336047篇
口腔科学   67743篇
临床医学   215947篇
内科学   469864篇
皮肤病学   48138篇
神经病学   201507篇
特种医学   96345篇
外国民族医学   886篇
外科学   361257篇
综合类   56258篇
现状与发展   1篇
一般理论   979篇
预防医学   190823篇
眼科学   55553篇
药学   178005篇
  4篇
中国医学   4376篇
肿瘤学   126768篇
  2018年   24300篇
  2016年   20658篇
  2015年   23408篇
  2014年   33731篇
  2013年   51072篇
  2012年   69060篇
  2011年   72609篇
  2010年   42725篇
  2009年   41110篇
  2008年   69101篇
  2007年   73492篇
  2006年   74396篇
  2005年   72462篇
  2004年   69740篇
  2003年   67439篇
  2002年   66700篇
  2001年   112531篇
  2000年   116601篇
  1999年   98459篇
  1998年   27986篇
  1997年   25612篇
  1996年   25528篇
  1995年   24674篇
  1994年   23218篇
  1993年   21603篇
  1992年   79435篇
  1991年   76444篇
  1990年   73624篇
  1989年   70883篇
  1988年   65879篇
  1987年   64849篇
  1986年   61366篇
  1985年   58441篇
  1984年   44257篇
  1983年   37689篇
  1982年   22925篇
  1981年   20366篇
  1980年   19076篇
  1979年   41327篇
  1978年   29026篇
  1977年   24376篇
  1976年   22875篇
  1975年   23991篇
  1974年   29681篇
  1973年   28077篇
  1972年   26240篇
  1971年   24166篇
  1970年   22784篇
  1969年   21102篇
  1968年   19150篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
71.
Bifid mandibular canal.   总被引:1,自引:0,他引:1  
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women.  相似文献   
72.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed.  相似文献   
73.
74.
75.
Zusammenfassung Viele gastrointestinale Tumoren werden im Rahmen multimodaler Therapiekonzepte behandelt. Für den Chirurgen ist die neoadjuvante, präoperative Behandlung von besonderem Interesse, da sie durch therapiebedingte Nebenwirkungen und Komplikationen zu einer Beeinflussung des postoperativen Verlaufs führen kann. Die neoadjuvante Radiochemotherapie ist fester Bestandteil der Therapie beim primären T4-Rektumkarzinom, beim Rektumkarzinomrezidiv und bei tief sitzenden primären Rektumkarzinomen. Durch Erhöhung der R0-Resektionsrate können die lokale Tumorkontrolle verbessert und die Überlebenszeit verlängert werden. Die postoperative Komplikationsrate ist dabei nicht wesentlich erhöht. In der Behandlung des primär resektablen Ösophaguskarzinoms deutet sich ein Vorteil der neoadjuvanten Radiochemotherapie im Vergleich zur alleinigen Chirurgie an. Beim lokal fortgeschrittenen Ösophaguskarzinom bietet die präoperative Radiochemotherapie häufig die einzige Chance zur Resektion, jedoch mit einer deutlich erhöhten postoperativen Morbidität und Mortalität. Die Wirksamkeit und Sicherheit einer neoadjuvanten Chemo- oder kombinierten Radiochemotherapie beim fortgeschrittenen Magenkarzinom wird derzeit im Rahmen von Studienprotokollen untersucht.  相似文献   
76.
77.
In chronic myeloid leukaemia, CD34(+) stem/progenitor cells appear resistant to imatinib mesylate (IM) in vitro and in vivo. To investigate the underlying mechanism(s) of IM resistance, it is essential to quantify Bcr-Abl kinase status at the stem cell level. We developed a flow cytometry method to measure CrkL phosphorylation (P-CrkL) in samples with <10(4) cells. The method was first validated in wild-type (K562) and mutant (BAF3) BCR-ABL(+) as well as BCR-ABL(-) (HL60) cell lines. In response to increasing IM concentration, there was a linear reduction in P-CrkL, which was Bcr-Abl specific and correlated with known resistance. The results were comparable to those from Western blotting. The method also proved to be reproducible with small samples of normal and Ph(+) CD34(+) cells and was able to discriminate between Ph(-), sensitive and resistant Ph(+) cells. This assay should now enable investigators to unravel the mechanism(s) of IM resistance in stem cells.  相似文献   
78.
79.
We evaluated the acquisition and performance of a high-precision locomotor task in patients with Parkinson's disease (PD) and healthy subjects. All subjects walked on a treadmill and had to step repetitively as low as possible over an obstacle without touching it. During blocks 1 and 2, the subjects had full vision and received additional acoustic warning and feedback signals. During block 3, vision became restricted. Changes in foot clearance and the number of obstacle hits were evaluated. Initially, PD patients performed poorer and improved foot clearance slower. After task repetition, the groups performed similarly. Restricting vision deteriorated performance in both groups. The similar performance of PD patients after task repetition might indicate that adequate training could improve adaptive locomotor behavior in PD patients.  相似文献   
80.
An increase in chronic beryllium disease (CBD) has been suggested due to higher industrial use of beryllium alloys. Since occupational CBD is a perfect phenocopy of sarcoidosis, it might be misdiagnosed as sarcoidosis. In the current it was hypothesised that CBD exists in cohorts of sarcoidosis patients. In a prospective case study, sarcoidosis patients were evaluated for potential beryllium exposure. In those patients in whom beryllium exposure was confirmed and beryllium hypersensitivity demonstrated, the diagnosis of sarcoidosis was rejected and corrected to CBD. In 84 patients seen for re-evaluation or making a diagnosis of sarcoidosis, beryllium exposure was recognised and a diagnosis of CBD was made in 34 out of 84 patients. The time lag between clinical diagnosis of sarcoidosis and the final diagnosis of CBD ranged 0-18 yrs (median 3 yrs) and the mean (range) age at time of diagnosis of CBD was 43.9(25-80) yrs. Beryllium-contaminated workplaces causing disease encompassed a wide spectrum of industries and technical trades in which beryllium-exposure is generally not perceived as a health hazard. In conclusion, chronic beryllium disease still belongs to the spectrum of differential diagnoses of granulomatous disorders.  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