全文获取类型
收费全文 | 918篇 |
免费 | 34篇 |
国内免费 | 88篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 8篇 |
妇产科学 | 8篇 |
基础医学 | 93篇 |
口腔科学 | 17篇 |
临床医学 | 97篇 |
内科学 | 346篇 |
皮肤病学 | 4篇 |
神经病学 | 25篇 |
特种医学 | 69篇 |
外科学 | 133篇 |
综合类 | 86篇 |
预防医学 | 16篇 |
眼科学 | 10篇 |
药学 | 23篇 |
中国医学 | 4篇 |
肿瘤学 | 74篇 |
出版年
2023年 | 19篇 |
2022年 | 42篇 |
2021年 | 33篇 |
2020年 | 33篇 |
2019年 | 33篇 |
2018年 | 22篇 |
2017年 | 30篇 |
2016年 | 34篇 |
2015年 | 43篇 |
2014年 | 63篇 |
2013年 | 62篇 |
2012年 | 40篇 |
2011年 | 51篇 |
2010年 | 41篇 |
2009年 | 57篇 |
2008年 | 54篇 |
2007年 | 24篇 |
2006年 | 51篇 |
2005年 | 40篇 |
2004年 | 27篇 |
2003年 | 21篇 |
2002年 | 24篇 |
2001年 | 20篇 |
2000年 | 10篇 |
1999年 | 24篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 7篇 |
1995年 | 15篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1040条查询结果,搜索用时 12 毫秒
1.
Timo Rath Lukas Pfeifer Clemens Neufert reas Kremer Moritz Leppkes Arthur Hoffman Markus F Neurath Steffen Zopf 《World journal of gastroenterology : WJG》2020,26(16):1962-1970
BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode. 相似文献
2.
W. S. L. Stebbings M. J. G. Farthing J. R. Puddefoot Elizabeth Anderson G. P. Vinson J. M. A. Northover R. F. M. Wood 《Journal of cancer research and clinical oncology》1988,114(2):208-211
Summary To evaluate the potential effect of androgens on the development and growth of human colorectal adenomas, the prevalence and concentration of cytosolic androgen receptors (AR) were analysed in 26 adenomas and 19 samples of normal colonic mucosa by a hybrid ligand receptor-binding assay. AR were detected in 7 of the adenomas (26.9%), and in 6 of the normal mucosa samples (31.6%). In the adenomas, AR levels demonstrated were low, ranging from 6 to 31 fmol/mg cytosol protein, and dissociation constants (Kds) ranged from 0.17–2.7x10-9
M. Of 13 adenomas excised from men, 6 (46%) had positive receptor activity, whereas only 1 of 13 (7.7%) from women was positive (P=0.03, Fisher's exact test). There was no correlation between AR titre and patient age, or between adenoma size and histological type or degree of dysplasia. In normal mucosa, AR levels ranged from 7 to 33 fmol/mg and Kds ranges from 0.24–3.1x10-9
M. There was no significant difference between either AR prevalence or levels in the adenomas and normal mucosa. The sex difference was exclusive to the adenoma. Endogenous androgen may play a role in adenoma development early in the promotional process. 相似文献
3.
大型垂体瘤不同手术入路治疗的比较研究 总被引:1,自引:0,他引:1
本文回顾性比较106例大型垂体瘤的开颅和经蝶手术治疗的比较。开颅组58例,经蝶组48例。开颅组肿瘤次全切除9例,大部切除48例,部分切除1例;经蝶组全切除35例,大部切除12例,部分切除1例。开颅组术后视力好转率71%,无变化12例,恶化3例。手术后偏盲好转率67%;经蝶组手术后视力好转率77%,无变化者11例,无1例恶化。手术后偏盲好转率93%。开颅组20例有额叶挫伤,其中1例并发脑内血肿,死亡4例。作者认为垂体腺瘤不长向鞍旁、海绵窦、前颅窝底和脚间池和肿瘤不呈瓶颈样生长者,都应优先考虑经蝶窦入路手术。 相似文献
4.
Sunil Kumar Saxena S. Gopalakrishnan 《Indian journal of otolaryngology and head and neck surgery》2003,55(4):281-282
Despite the common occurrence of pleomorphic adenoma of major salivary glands, intranasal pleomorphic adenoma are rare. We
present a ease of pleomorphic adenoma of the nasal septum along with a brief review of literature. The histological nature
of this lesion in comparison to other salivary gland tumours and the importance of an accurate diagnosis has been stressed. 相似文献
5.
6.
细胞角蛋白19、galectin-3、HBME-1在甲状腺病变上的表达及鉴别诊断意义 总被引:12,自引:2,他引:12
目的 研究细胞角蛋白(CK)19、galectin(Gal)-3、HBME-1在甲状腺不同病变表达的特点及鉴别诊断中的应用价值。方法 应用免疫组织化学EnVision法检测了21例结节性甲状腺肿(结甲)、14例毒性甲状腺肿(甲亢)、15例甲状腺滤泡性腺瘤(腺瘤)、13例滤泡性癌、13例滤泡型乳头状癌及48例经典型乳头状癌中单克隆抗体CK19、Gal-3、HBME-1的表达。结果 甲状腺病变中3种标记表达均位于细胞质;CK19、Gal-3、HBME-1的表达在甲状腺良性病变(结甲、甲亢、腺瘤)大多为弱阳性或阴性,而滤泡性癌阳性明显增加、乳头状癌(滤泡型及经典型)大多为中、强阳性,3种标记在甲状腺不同病变的阳性表达率结甲为52.4%(11/21)、9.5%(2/21)、19.0%(4/21),甲亢为50.0%(7/14)、7.1%(1/14)、7.1%(1/14),腺瘤为60%(9/15)、13.3%(2/15)、13.3%(2/15),滤泡性癌为76.9%(10/13)、61.5%(8/13)、53.8%(7/13),滤泡型乳头状癌为:100%(13/13)、84.6%(11/13)、92.3%(12/13),经典型乳头状癌为100%(48/48)、93.8%(45/48)、95.8%(46/48);在甲状腺良性病变(结甲、甲亢、腺瘤)与恶性病变(滤泡性癌、乳头状癌)间3种标记差异均有显著性(P均=0.000);同时3种标记在滤泡样病变即腺瘤、滤泡性癌和滤泡型乳头状癌间亦有显著差异(CK19:P=0.038,Gal-3:P=0.001,HBME-1:P=0.000)。结甲有9例,甲亢有7例,腺瘤有6例3种标记均不表达,滤泡性癌仅有1例,而乳头状癌(滤泡型及经典型)没有病例3种标记均不表达,同一病例有2种以上阳性表达在结甲、甲亢、腺瘤、滤泡性癌、滤泡型乳头状癌和经典型乳头状癌中分别为14.2%(3/21)、21.4%(3/14)、20.0%(3/15)、69.2%(9/13)、92.3%(12/13)、100.0%(48/48),在甲状腺良性病变与恶性病变间以及滤泡样病变间差异亦有显著性(P=0.000)。结论 CK19、Gal-3、HBME-1的检测尤其是联合检测对甲状腺病变的诊断、鉴别诊断具有较高的实用价值。 相似文献
7.
K. Kovacs E. Horvath B. Corenblum A. M. T. Sirek G. Penz C. Ezrin 《Virchows Archiv : an international journal of pathology》1975,366(2):113-123
Summary Morphologic studies of pituitary neoplasms removed by surgery from 36 human patients revealed 8 chromophobe adenomas which differed clearly from the remaining tumors. The cytoplasm of the adenoma cells failed to stain with PAS, aniline blue, aldehyde fuchsin, aldehyde thionin, orange G or light green, but positively stained granules were found by using erythrosine or carmoisine. Immunoperoxidase technique disclosed the presence of prolactin in the cytoplasm of some adenoma cells. The adenoma cells exhibited distinct ultrastructural features such as well developed rough surfaced endoplasmic reticulum with Nebenkern formation, prominence of Golgi apparatus, presence of misplaced exocytosis as well as pleomorphism of secretory granules with a considerable variation of size ranging from 130 to 500 nm in diameter. Thus, by electron microscopy the adenoma cells showed a close resemblance to prolactin cells of the non-tumorous pituitary glands except for the reduced size and number of secretory granules.These chromophobe adenomas are regarded as representing a distinct pathological entity clearly distinguishable from other forms of pituitary neoplasms. In view of the morphologic findings and the elevation of blood prolactin level (measured in 3 patients) the term, sparsely granulated prolactin producing pituitary adenoma, appears to be the most appropriate one to designate these tumors.The authors wish to thank Dr. H. Friesen for providing the anti-human prolactin and Dr. L. A. Sternberger for the peroxidase-anti-peroxidase complex. The excellent technical assistance of Mrs. Gezina Ilse and Miss Nancy Macphail and the valuable secretarial help of Mrs. Maureen Rowling are appreciated.The work was supported in part by MA-552 grant of the Medical Research Council of Canada and by the St. Michael's Hospital Research Society. 相似文献
8.
我们应用三维结构(3-D)再构成计算机系统,以0.2mm间隔连续切片,HE染色,对50例经纤维结肠镜切除的大肠腺瘤各种异型上皮的体积及分布规律进行研究。其中癌变17例(34%),其平均体积是单纯腺瘤的3.4倍。腺瘤体积越大,其癌变率越高,但体积较小的亚有蒂型腺瘤也有很高癌变率(25%)。研究结果表明腺瘤体积大小与平均异型度无相关关系。用常规方法切片,仅检出14例有癌变,漏诊率18%。为提高腺瘤癌变检出率,至少应以0.6mm间隔连续切片。此种方法对准确判定断端有无癌浸润也有重要意义。 相似文献
9.
目的 观察大肠癌和腺瘤组织细胞凋亡的特征,探讨细胞凋亡和增殖在大肠癌和腺瘤组织中的意义。方法 采用脱氧核糖核酸末端转移酶介导的dUTP缺口末端标记(TUNEL)法检测凋亡细胞,以凋亡细胞百分率作为凋亡指数(Apopticindex,AI)对15例大肠癌、10例腺瘤、5例正常大肠粘膜进行凋亡细胞原位观察。结果 TUNEL阳性物质位于细胞核内,常聚集于核膜附近,呈新月状和块状。大肠正常粘膜TUNEL阳性细胞全部位于表层上皮中,数量很少(AI=1.74±1.01),腺瘤组织中TUNEL阳性细胞相对较多(AI=33.46±11.39),大肠癌组织TUNEL阳性细胞散在分布,与腺瘤相比数量明显减少(AI=11.08±4.27)(P<0.01)。结合增殖细胞核抗原(PCNA)实验结果可见,腺瘤组织中AI,PI(PI=27.24±7.66)均高,而大肠癌组织中则以细胞增殖(PI=54.18±10.41)占优势。结论 大肠肿瘤癌变过程中不仅存在活跃的细胞增殖,而且有大量的细胞凋亡,因而增加了粘膜上皮的不稳定性,高的增殖能力通过选择而占优势,从而导致癌变的发生。 相似文献
10.
Dural enhancement in pituitary macroadenomas 总被引:1,自引:0,他引:1
We describe the normal dural enhancement patterns of the sellar region and determine whether the duramater is affected by
pituitary macroadenomas. Dural enhancement appeared to be usually abnormal in 20 patients with pituitary macroadenoma compared
with 20 control patients, mainly at the planum sphenoidale and carotid sulcus. However dural changes are subtle and their
recognition requires knowledge of the normal enhancement patterns. Dural changes, reported in a variety of inflammatory and
infectious dural diseases and after surgery, are not specific and may be also seen in pituitary macroadenomas.
Received: 12 December 1998 Accepted: 3 November 1999 相似文献