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   565篇
  免费   27篇
耳鼻咽喉   18篇
儿科学   6篇
妇产科学   18篇
基础医学   81篇
口腔科学   10篇
临床医学   39篇
内科学   138篇
皮肤病学   8篇
神经病学   55篇
特种医学   21篇
外科学   74篇
预防医学   27篇
药学   44篇
肿瘤学   53篇
  2021年   12篇
  2020年   12篇
  2019年   10篇
  2018年   9篇
  2017年   6篇
  2016年   14篇
  2015年   16篇
  2014年   14篇
  2013年   26篇
  2012年   38篇
  2011年   29篇
  2010年   14篇
  2009年   15篇
  2008年   24篇
  2007年   30篇
  2006年   23篇
  2005年   22篇
  2004年   19篇
  2003年   19篇
  2002年   16篇
  2001年   19篇
  2000年   19篇
  1999年   18篇
  1998年   13篇
  1997年   8篇
  1996年   7篇
  1995年   5篇
  1994年   4篇
  1993年   5篇
  1992年   7篇
  1991年   11篇
  1990年   8篇
  1989年   8篇
  1988年   15篇
  1987年   4篇
  1986年   14篇
  1985年   6篇
  1984年   2篇
  1983年   4篇
  1982年   3篇
  1981年   4篇
  1980年   6篇
  1979年   8篇
  1978年   6篇
  1976年   2篇
  1972年   2篇
  1971年   4篇
  1907年   2篇
  1895年   1篇
  1893年   1篇
排序方式: 共有592条查询结果,搜索用时 16 毫秒
1.
ABSTRACT

Objective: The purpose of this study was to examine the influence of a total knee arthroplasty (TKA) on linked cranial and caudal structures.

Methods: Thirty-five (14f/21m) subjects participated in this study: 15 subjects (9f, 6m) pre- and post- TKA and a control group of 20 subjects (5f, 15m). The measurements included: jaw condyle position and movement, back scan, plantar pressure distribution, and body sway.

Results: There were no significant differences in electronic position analysis of the jaw; however, the protrusion of the TKA group improved (p = 0.001). The test group had a more anteriorly inclined thoracic spine and a less pronounced lumbar lordosis. Before and after surgery, the body sway in the test group was larger.

Conclusion: The TKA affected most prominently the static mechanisms of the postural control and the spine position. The trajectories of the mandible during protrusion also changed slightly.  相似文献   
2.
3.
Previously we have shown that the dorsal lateral geniculate body (LGB), which is strictly visual in sighted mammals, receives a strong auditory input in the naturally blind mole rat (Spalax ehrenbergi). Here we show with the 2-deoxyglucose technique and with single-unit recordings that in this species the initially non-degenerated visual cortex, as defined by its connection with LGB, is also activated by the auditory modality. These findings suggest that cross-modal compensation may occur as a natural consequence of the degeneration of a sense organ.  相似文献   
4.
5.
G. Heil  A. Ganser 《Der Onkologe》1998,4(9):791-797
Bei den akuten myeloischen Leuk?mien (AML) handelt es sich um heterogene, maligne Erkrankungen des h?matopoetischen Systems, denen die maligne Transformation einer h?matopoetischen Vorl?uferzelle zugrunde liegt [9]. Folge dieser Transformation ist ein Verlust oder die Einschr?nkung des Differenzierungspotentials der Zellen mit einem Ausreifungsstop auf einem frühen Stadium der Myelopoese. Bei erhaltener Proliferationskapazit?t kommt es zur klonalen Expansion der malignen Zellen mit sukzessiver „Verdr?ngung” der normalen H?matopoese, an deren Folgen der Patient unbehandelt innerhalb weniger Wochen verstirbt. Haupttodesursachen sind Blutungen und /oder Infektionen.  相似文献   
6.
P Heil  H Scheich 《Neuroreport》1992,3(5):381-384
The existence of an ontogenetic shift of tonotopic organization throughout the auditory pathway concomitant with cochlea maturation is a matter of controversy. Using the 2-deoxyglucose method we demonstrate here for the first time the shift phenomenon in an auditory forebrain structure, field L, the auditory cortex analogue of the chick. During the first postnatal month isofrequency contours move to positions where, in younger chicks, lower frequencies (up to half an octave) are represented. This developmentally changing place code of sound frequencies at the forebrain level is similar to the one previously reported for brain stem auditory nuclei. It raises the question of constancy of frequency-related pitch perception during development and may be a complication of early auditory learning and memory.  相似文献   
7.
Tumor targeting by an aptamer.   总被引:10,自引:0,他引:10  
Aptamers are small oligonucleotides that are selected to bind tightly and specifically to a target molecule. We sought to determine whether aptamers have potential for in vivo delivery of radioisotopes or cytotoxic agents. METHODS: TTA1, an aptamer to the extracellular matrix protein tenascin-C, was prepared in fluorescent and radiolabeled forms. After in vivo administration, uptake and tumor distribution of Rhodamine Red-X-labeled aptamer was studied by fluorescence microscopy. In glioblastoma (U251) and breast cancer (MDA-MB-435) tumor xenografts, biodistribution and imaging studies were performed using TTA1 radiolabeled with (99m)Tc. Tenascin-C levels and tumor uptake were studied in a variety of additional human tumor xenografts. To assess the effect of radiometal chelate on biodistribution, mercapto-acetyl diglycine (MAG(2)) was compared with diethylenetriaminepentaacetic acid and with MAG(2)-3,400-molecular-weight PEG (PEG(3,400)). RESULTS: Intravenous injection of fluorescent aptamer TTA1 produced bright perivascular fluorescence in a xenografted human tumor within 10 min. In the ensuing 3 h, fluorescence diffused throughout the tumor. Labeled with (99m)Tc, TTA1 displayed rapid blood clearance, a half-life of less than 2 min, and rapid tumor penetration: 6% injected dose (%ID)/g at 10 min. Tumor retention was durable, with 2.7 %ID/g at 60 min and a long-lived phase that stabilized at 1 %ID/g. Rapid tumor uptake and blood clearance yielded a tumor-to-blood ratio of 50 within 3 h. Both renal and hepatic clearance pathways were observed. Using the (99m)Tc-labeled aptamer, images of glioblastoma and breast tumors were obtained by planar scintigraphy. Aptamer uptake, seen in several different human tumors, required the presence of the target protein, human tenascin-C. Modification of the MAG(2) radiometal chelator dramatically altered the uptake and clearance patterns. CONCLUSION: TTA1 is taken up by a variety of solid tumors including breast, glioblastoma, lung, and colon. Rapid uptake by tumors and rapid clearance from the blood and other nontarget tissues enables clear tumor imaging. As synthetic molecules, aptamers are readily modified in a site-specific manner. A variety of aptamer conjugates accumulate in tumors, suggesting imaging and potentially therapeutic applications.  相似文献   
8.
9.
10.
Ruchkin and Johnson (1991) claim that the mode of responding used by Rösler & Heil (1991) may have camouflaged effects of a negative slow wave that Ruckin et al. (1988) had found to be related to the difficulty of mental calculation problems. This criticism is addressed by three arguments which support the interpretation of Rösler and Heil (1991). According to this view, the negative slow wave in question is more likely related to unspecific processing factors, such as effort and event expectation, than to specific processing demands such as these induced by mental arithmetic.  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