全文获取类型
收费全文 | 597篇 |
免费 | 25篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 9篇 |
妇产科学 | 6篇 |
基础医学 | 44篇 |
口腔科学 | 25篇 |
临床医学 | 46篇 |
内科学 | 120篇 |
皮肤病学 | 13篇 |
神经病学 | 12篇 |
特种医学 | 115篇 |
外科学 | 88篇 |
综合类 | 90篇 |
预防医学 | 12篇 |
眼科学 | 4篇 |
药学 | 49篇 |
肿瘤学 | 21篇 |
出版年
2022年 | 9篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 15篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 16篇 |
2011年 | 19篇 |
2010年 | 20篇 |
2009年 | 19篇 |
2008年 | 25篇 |
2007年 | 39篇 |
2006年 | 25篇 |
2005年 | 33篇 |
2004年 | 15篇 |
2003年 | 23篇 |
2002年 | 12篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 20篇 |
1998年 | 38篇 |
1997年 | 26篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 18篇 |
1988年 | 18篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 7篇 |
1973年 | 1篇 |
排序方式: 共有655条查询结果,搜索用时 9 毫秒
1.
2.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
3.
4.
5.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2
6.
Ann E Barr Fayez F Safadi Irene Gorzelany Mamta Amin Steven N Popoff Mary F Barbe 《Journal of bone and mineral research》2003,18(11):2023-2032
Work-related repetitive motion disorders are costly. Immunohistochemical changes in bones resulting from repetitive reaching and grasping in 17 rats were examined. After 3-6 weeks, numbers of ED1+ macrophages and osteoclasts increased at periosteal surfaces of sites of muscle and interosseous membrane attachment and metaphyses of reach and nonreach forelimbs. These findings indicate pathological overloading leading to inflammation and subsequent bone resorption. INTRODUCTION: Sixty-five percent of all occupational illnesses in U.S. private industry are attributed to musculoskeletal disorders arising from the performance of repeated motion, yet the precise mechanisms of tissue pathophysiology have yet to be determined for work-related musculoskeletal disorders. This study investigates changes in upper extremity bone tissues resulting from performance of a voluntary highly repetitive, negligible force reaching and grasping task in rats. MATERIALS AND METHODS: Seventeen rats reached an average of 8.3 times/minute for 45-mg food pellets for 2 h/day, 3 days/week for up to 12 weeks. Seven rats served as normal or trained controls. Radius, ulna, humerus, and scapula were collected bilaterally as follows: radius and ulna at 0, 3, 4, 5, 6, and 12 weeks and humerus and scapula at 0, 4, and 6 weeks. Bones were examined for ED1-immunoreactive mononuclear cells and osteoclasts. Double-labeling immunohistochemistry was performed for ED1 (monocyte/macrophage lineage cell marker) and TRACP (osteoclast marker) to confirm that ED1+ multinucleated cells were osteoclasts. Differences in the number of ED1+ cells over time were analyzed by ANOVA. RESULTS: Between 3 and 6 weeks of task performance, the number of ED1+ mononuclear cells and osteoclasts increased significantly at the periosteal surfaces of the distal radius and ulna of the reach and nonreach limbs compared with control rats. These cells also increased at periosteal surfaces of humerus and scapula of both forelimbs by 4-6 weeks. These cellular increases were greatest at muscle attachments and metaphyseal regions, but they were also present at some interosseous membrane attachments. The number of ED1+ cells decreased to control levels in radius and ulna by 12 weeks. CONCLUSIONS: Increases in ED1+ mononuclear cells and osteoclasts indicate that highly repetitive, negligible force reaching causes pathological overloading of bone leading to inflammation and osteolysis of periosteal bone tissues. 相似文献
7.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
8.
9.
10.
BACKGROUND: The relation between latex-specific IgE titer and the type or total number of latex-induced symptoms has not been previously investigated. OBJECTIVE: We sought to determine the association of latex-IgE in vitro assay results with the type, number, or severity of symptoms in patients allergic to latex. METHODS: Ninety-one patients with positive histories and positive skin test responses were identified as having type I allergy. Data was collected for reported symptoms after latex exposure. Symptom severity was quantitated by 2 scores: (1) the total number of symptoms to latex exposure and (2) a symptom severity score (3 = anaphylaxis, 2 = asthma, and 1 = rhinoconjunctivitis, urticaria, or both). All subjects underwent AlaSTAT and CAP tests. RESULTS: AlaSTAT class was associated with total number of symptoms (r = 0.32, P <.001) and severity score (r = 0.33, P <.002). Similarly, CAP class was associated with both number of symptoms (r = 0.32, P <. 0001) and severity score (r = 0.31, P <.001). Among the symptoms reported, asthma had the strongest association with a positive in vitro IgE assay (odds ratio = 6.7 [95% confidence interval = 1.9, 25. 6]), followed by urticaria (odds ratio = 1.9 [95% confidence interval = 0.8, 4.6]). Contact dermatitis had no statistical association with in vitro assays in this study. AlaSTAT and CAP class correlated together significantly (r = 0.58, P <.001). CONCLUSION: Patients allergic to latex with higher AlaSTAT or CAP class were more symptomatic. Increasing class or titer also predicted more severe symptoms. Higher class of either the AlaSTAT or CAP assay to latex was strongly associated with latex-related asthma and urticaria and marginally associated with latex-related rhinoconjunctivitis. 相似文献