全文获取类型
收费全文 | 4425篇 |
免费 | 267篇 |
国内免费 | 106篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 94篇 |
妇产科学 | 64篇 |
基础医学 | 581篇 |
口腔科学 | 224篇 |
临床医学 | 368篇 |
内科学 | 602篇 |
皮肤病学 | 69篇 |
神经病学 | 439篇 |
特种医学 | 156篇 |
外科学 | 430篇 |
综合类 | 507篇 |
预防医学 | 308篇 |
眼科学 | 125篇 |
药学 | 374篇 |
中国医学 | 218篇 |
肿瘤学 | 188篇 |
出版年
2023年 | 62篇 |
2022年 | 73篇 |
2021年 | 176篇 |
2020年 | 112篇 |
2019年 | 108篇 |
2018年 | 125篇 |
2017年 | 128篇 |
2016年 | 122篇 |
2015年 | 108篇 |
2014年 | 229篇 |
2013年 | 291篇 |
2012年 | 234篇 |
2011年 | 218篇 |
2010年 | 175篇 |
2009年 | 179篇 |
2008年 | 180篇 |
2007年 | 159篇 |
2006年 | 168篇 |
2005年 | 124篇 |
2004年 | 139篇 |
2003年 | 114篇 |
2002年 | 93篇 |
2001年 | 100篇 |
2000年 | 71篇 |
1999年 | 81篇 |
1998年 | 79篇 |
1997年 | 82篇 |
1996年 | 49篇 |
1995年 | 53篇 |
1994年 | 46篇 |
1993年 | 62篇 |
1992年 | 63篇 |
1991年 | 47篇 |
1990年 | 66篇 |
1989年 | 54篇 |
1988年 | 57篇 |
1987年 | 42篇 |
1986年 | 38篇 |
1985年 | 71篇 |
1984年 | 64篇 |
1983年 | 36篇 |
1982年 | 51篇 |
1981年 | 52篇 |
1980年 | 48篇 |
1979年 | 34篇 |
1978年 | 28篇 |
1977年 | 22篇 |
1976年 | 30篇 |
1975年 | 15篇 |
1974年 | 8篇 |
排序方式: 共有4798条查询结果,搜索用时 46 毫秒
21.
目的观察铁筷子多糖(Heborus thibetanus Franch polysaccharose,HFPS)对小鼠体内肉瘤S180生长的影响及荷瘤鼠肉瘤、胸腺组织的组织学变化。方法设立正常对照组、肿瘤模型组、铁筷子多糖处理组和阳性对照组(复方天仙胶囊处理组)。用小鼠肉瘤S180细胞株建立动物肿瘤模型,灌胃给予荷S180小鼠HFPS后,计算抑瘤率及观察荷瘤鼠胸腺组织及肉瘤组织的形态变化。结果铁筷子多糖有明显抑制S180肉瘤细胞体内生长的作用;对照鼠S180肉瘤模型,多糖(HFPS)治疗组荷瘤小鼠胸腺皮质厚度较明显增加,胸腺细胞增多;小鼠肉瘤组织中肉瘤细胞发生不同程度的变性和坏死以及中性粒细胞、淋巴细胞为主的炎细胞浸润。结论铁筷子多糖有抑制S180细胞体内生长的作用。 相似文献
22.
Martin Sjbeck Mattias Haglund Annette Persson Kerstin Sturesson Elisabet Englund 《Neuropathology》2003,23(4):290-295
Tissue microarrays (TMA) consist of up to 1000 cylindrical tissue cores from different donor paraffin blocks relocated into one recipient block, allowing for efficient histopathological studies by fluorescence in situ hybridization, RNA in situ hybridization or immunohistochemistry. On the background of the increasing interest of the TMA technique in cancer research and the suggestion of its application also in studies of non‐neoplastic intracranial disorders, the technique was applied to pathologic white matter in AD brains. Eight cases with AD and concomitant white matter pathology were neuropathologically diagnosed on whole brain coronal slides. The TMA technique was used to grade severity of white matter pathology and to quantify small vessels with traditional staining and immunohistochemical markers. These measurements were compared with the whole brain neuropathological assessment. The technique produced good results with preserved tissue structures as confirmed by the whole brain evaluation. Severity of white matter pathology evaluated on the TMA cores correlated negatively with small vessel quantities, and statistically significant differences in vessel quantities paralleled different grades of white matter pathology. It is concluded that the TMA technique could be further utilized in studies of dementing disorders, and may have its advantages in large, clinically well‐characterized materials (e.g. in quantitative mapping of white matter changes). 相似文献
23.
LYNDA E ALBERTYN 《Journal of Medical Imaging and Radiation Oncology》1992,36(1):17-22
Both systemic and local therapy, for conditions of the breast and unrelated to it, may produce manuno-graphic changes. Some of these are characteristic, such as the pattern of scarring seen in reduction mammo-plasty. In many other instances, however, the changes produced overlap features commonly seen in malignancy. A knowledge of the timing, natural history and spectrum of these changes will aid mammographic interpretation. 相似文献
24.
Plasma concentrations of prolactin, noradrenaline, vasopressin and oxytocin during and after a prolonged epileptic seizure 总被引:4,自引:0,他引:4
The time course and extent of changes in plasma prolactin, noradrenaline, vasopressin and oxytocin levels is reported following serial observations of a prolonged epileptic seizure arising in the temporal lobe, recorded by video-EEG-telemetry, in which the epileptic activity evolved from a simple partial to complex partial to secondarily generalised attack. The prolactin levels were markedly elevated during the phase of the simple partial seizure, at a time when consciousness was preserved, when motor activity was minimal and when EEG activity was highly localised. The hormonal levels continued to rise during the subsequent seizure evolution, suggesting that the duration (or intensity) of the seizure is an important, perhaps the most important, factor determining the degree of prolactin release during limbic seizures. Indeed, the prolactin elevation in this case (26 times the baseline level) is higher than any previously recorded, reflecting the unusual duration and intensity of this seizure. We did not observe the phenomenon of "exhaustion" of prolactin release and levels peaked after 49 min, and were high for over 2 h after the onset of the seizure, and after the convulsion had ceased. The concentrations of vasopressin, oxytocin and noradrenaline remained low during the aura, but rapidly increased during the phase of generalisation. The oxytocin and noradrenaline levels peaked during the phase of generalised convulsion, but the vasopressin levels peaked well into the post ictal phase, and remained high for several hours. The differing patterns of hormone release are likely to be related to the different anatomical sites of the hypothalamic perikarya, the relative importance of excitatory and inhibitory hypophysiotrophic agents in the release of anterior pituitary hormones and the localised release of neuromodulatory agents. 相似文献
25.
管状骨增宽牵引成骨组织形态学变化的实验研究 总被引:10,自引:0,他引:10
目的 探讨管状骨增宽牵引后新骨形成的变化。方法 在成年山羊的后肢放置2只增宽牵引器。实验组9只术后第8天牵引,对照组3只不牵引。牵引完毕后不同时期,各宰杀3只,评价管状骨增宽牵引后新骨形成的质和量。结果 实验组胫骨平均增宽7.83mm,X射线见牵引间隙逐渐变模糊,暴露侧有骨不连,非暴露侧成骨良好,牵引完毕3个月,未暴露侧新形成板层骨与原来胫骨融为一体,而暴露侧骨不连区为致密纤维组织。结论 管状骨增宽牵引成骨后,两侧牵引间隙成骨不一致,良好的血供,对新骨形成至关重要。 相似文献
26.
J Liu J D Cassidy A Allan P J Neame J S Mort P J Roughley 《Journal of orthopaedic research》1992,10(5):621-630
Human cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site. 相似文献
27.
28.
改善微循环对大鼠坐骨神经损害血管内皮细胞生长因子表达及病理改变的影响 总被引:1,自引:0,他引:1
目的:探讨改善微循环对周围神经嵌压性损害血管内皮细胞生长因子(VEGF)表达和病理改变的影响。方法:分别检测坐骨神经嵌压后12、72h和7d背根神经节细胞VEGF水平与第4周神经干、神经节病理变化、脊髓病变神经元计数等,并运用正常对照组、模型组、前列地尔组和丁咯地尔组采用SPSS10.0统计软件进行方差分析统计处理。结果:嵌压后72hVEGF水平达到高峰,与正常对照组比较,其余各组均显著增加(P<0.01,P<0.05);前列地尔组和丁咯地尔组较模型组为优(P<0.01,P<0.05);嵌压后4周前列地尔组和丁咯地尔组的神经干、神经节病理变化、脊髓病变神经元计数均优于模型组(P<0.05)。结论:对于周围神经嵌压性损害,改善微循环可增加VEGF的表达并减轻其病理损害,从而对周围神经嵌压性损害的修复具有促进作用。 相似文献
29.
30.
Van Buskirk Glenn A. González Mario A. Shah Vinod P. Barnhardt Scott Barrett Colin Berge Stephen Cleary Gary Chan Keith Flynn Gordon Foster Thomas Gale Robert Garrison Raymond Gochnour Scott Gotto Amanda Govil Sharad Gray Vivian A. Hammar James Harder Samuel Hoiberg Charles Hussain Ajaz Karp Carol Llanos Hector Mantelle Juan Noonan Patrick Swanson David Zerbe Horst 《Pharmaceutical research》1997,14(7):848-852
Pharmaceutical Research - 相似文献