全文获取类型
收费全文 | 148778篇 |
免费 | 13609篇 |
国内免费 | 8171篇 |
专业分类
耳鼻咽喉 | 1346篇 |
儿科学 | 2152篇 |
妇产科学 | 3000篇 |
基础医学 | 15275篇 |
口腔科学 | 3073篇 |
临床医学 | 18152篇 |
内科学 | 22661篇 |
皮肤病学 | 1775篇 |
神经病学 | 7171篇 |
特种医学 | 4977篇 |
外国民族医学 | 43篇 |
外科学 | 15446篇 |
综合类 | 24391篇 |
现状与发展 | 22篇 |
一般理论 | 19篇 |
预防医学 | 11240篇 |
眼科学 | 3795篇 |
药学 | 15873篇 |
127篇 | |
中国医学 | 8116篇 |
肿瘤学 | 11904篇 |
出版年
2024年 | 1293篇 |
2023年 | 1978篇 |
2022年 | 4561篇 |
2021年 | 6114篇 |
2020年 | 4755篇 |
2019年 | 4218篇 |
2018年 | 4456篇 |
2017年 | 4270篇 |
2016年 | 3819篇 |
2015年 | 5938篇 |
2014年 | 7677篇 |
2013年 | 7973篇 |
2012年 | 11428篇 |
2011年 | 12161篇 |
2010年 | 8587篇 |
2009年 | 7125篇 |
2008年 | 8806篇 |
2007年 | 8864篇 |
2006年 | 8409篇 |
2005年 | 7539篇 |
2004年 | 6036篇 |
2003年 | 5915篇 |
2002年 | 5065篇 |
2001年 | 4270篇 |
2000年 | 3497篇 |
1999年 | 2960篇 |
1998年 | 1467篇 |
1997年 | 1381篇 |
1996年 | 1086篇 |
1995年 | 1038篇 |
1994年 | 974篇 |
1993年 | 542篇 |
1992年 | 942篇 |
1991年 | 846篇 |
1990年 | 717篇 |
1989年 | 588篇 |
1988年 | 546篇 |
1987年 | 466篇 |
1986年 | 375篇 |
1985年 | 291篇 |
1984年 | 190篇 |
1983年 | 172篇 |
1982年 | 98篇 |
1981年 | 94篇 |
1979年 | 143篇 |
1978年 | 111篇 |
1977年 | 83篇 |
1974年 | 94篇 |
1973年 | 72篇 |
1972年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Role of type IV collagene and type IV collagenase in the invasion and metastasis of salivary adenoid cystic carcinoma] 下载免费PDF全文
Using immunohistochemical ABC method, the authors studied the distribution of type IV collagen and type IV collagenase in 25 cases ACC. The result showed type IV collagen was found in vascular and epithelial basement membrance, and in partly cyst of sieve-like and tubular pattern, and in cytoplasm of tumor cell. Type IV collagenase was detected in membrance and cytoplasm of tumor cell. Expression of type IV collagen and type IV collagenase were correlated with pathologic type, TNM stage and metastasis. Much positive staining of type IV collagen was found in sieve-tubular pattern, early stage of TNM and without metastasis, but much positive staining of type IV collagenase was found in solid pattern, later stage of TNM and metastasis. The result suggested that the loss of type IV collagen and over-expression of type IV collagenase may be markers of malignance of ACC. 相似文献
92.
18 Patients with calcifying odontogenic cyst underwent surgery in our Department from 1977 to 1993 were reported.8 male and 10 female aged from 11 to 52 with medium or 33 years were included.16 cases were pathologically confirmed as primary intraosseous cyst(central),and 2 as extraosseous cyst(peripheral).There was no recurrence after the local excision for preripheral calcifying odontogenic cyst and local curettage for central one.There were 3 in 6 cases of tumor typed cyst who had recurred postoperatively,two of them had recurred repeatedly and cured by means of local radiotherapy.The authors recommend that the tumor type of intraosseous calcifying odontogenic cyst be classified as a border-line tumor and treated as well as the principles of low malignant tumor.Post-operative radiotherapy could be used for recurrent cases. 相似文献
93.
94.
目的研究HOXC13 mRNA在成釉细胞瘤(ameloblastoma,AB)中的表达,探讨其发生的意义。方法采用原位杂交法检测47例AB(原发AB 29例,复发AB 14例,恶变AB 4例),同时选取骨纤维异样增殖症2例,牙源性角化囊性瘤(keratocystic odontogenic tumor,KCOT)10例,正常口腔黏膜上皮7例作对照。结果HOXC13 mRNA AB中阳性率为97.9%(46/47),10例KCOT中7例为HOXC13 mRNA阳性表达,但在7例正常口腔黏膜细胞中仅3例为HOXC13 mRNA阳性表达,AB、KCOT、正常黏膜三组间差异有统计学意义(χ^2=21.665,P=0.001),但角化及颗粒样变退化细胞却为阴性。在部分AB间质成纤维细胞质中也有阳性表达,2例骨纤维异常增殖症纤维也为阳性。结论在AB中存在HOXC13的高表达;HOXC13 mRNA在AB上皮中的表达有异质性,该基因可促进上皮的增殖,其丢失可导致上皮细胞的角化和退变。 相似文献
95.
96.
BACKGROUND: The prognosis of a tooth with periodontitis is affected by the amount of supporting bone. A key factor in retaining a tooth is the ratio of supported root surface. Currently, root surfaces cannot be accurately measured using conventional dental radiographs, which only measure the length of bone support on proximal surfaces. METHODS: Eight extracted, single-rooted teeth were 3-dimensionally digitized using a contact technique for true surface area measurements. Root length, projection area, and pixel values were then measured on digital radiographs. The accuracy of the ratio estimation of supported surface area from linear, area, and pixel values was calculated and compared. RESULTS: The mean error from linear estimation was 7.9%; the mean error from area estimation was 1.0%; and the mean error from pixel value estimation was 1.3%. One-way analysis of variance (ANOVA) showed significant differences in all estimations while Scheffé's analysis further revealed significant differences only in the linear estimation. CONCLUSIONS: A three-dimensional digitizing device could be used as a non-destructive method of measuring root surface area. The ratio of supported single-root surface area could be estimated with high accuracy from the projected area data acquired on the digital dental radiographs. The thickness data as reflected from the pixel values in the digital images did not improve the estimation accuracy. Estimations using only length data yielded significantly less accuracy. Digital dental x-ray images provide the potential for estimating the ratio of supported root surface efficiently. 相似文献
97.
目的:了解蜂胶及自制蜂胶奥硝唑合剂对人牙龈成纤维细胞的毒性作用,为蜂胶及合剂的临床推广应用提供理论依据.方法:人牙龈成纤维细胞在不同浓度的蜂胶、奥硝唑和自制蜂胶奥硝唑合剂中体外培养24 h,用MTT法测定细胞相对增殖率(RGR);选择细胞增殖率约为50%的药物浓度组,重新培养细胞24 h,更换成不含药物的培养液连续培养7 d,每天用MTT法测定吸光度值,了解细胞增殖回复情况.结果:0.5g/L蜂胶组的RGR达到93.9%,与蜂胶其他2组间的差别有统计学意义(P<0.05);奥硝唑溶液加入蜂胶后,对应浓度组比较,两合剂组的平均吸光度值均大于奥硝唑组,其中当奥硝唑浓度为0.4g/L和0.8g/L时,差别有统计学意义(P相似文献
98.
目的 利用蛋白质组技术探讨牙髓对中龋和热刺激的反应.方法 用双向电泳得到牙髓在中龋和热刺激状态下的二维电泳图谱,对差异点进行质谱鉴定.结果 经Image Master2-D Platinum 5.0软件分析显示,正常牙髓和中龋牙髓的蛋白表达无显著差异;热损伤牙髓有2个蛋白点缺失,8个蛋白点下调.质谱分析鉴定了7种蛋白质.结论 本实验条件下,中龋牙髓的蛋白质表达与正常牙髓无显著差异,热刺激可造成部分蛋白表达的下调. 相似文献
99.
Soares RV Lin T Siqueira CC Bruno LS Li X Oppenheim FG Offner G Troxler RF 《Archives of oral biology》2004,49(5):337-343
Micelles represent macromolecular structures in saliva and the aim of this study was to identify salivary proteins that occur in these globular particles. Micelles were isolated from whole saliva (WS) collected from three individuals and analysed in different experiments. Samples were subjected to polyacrylamide gel electrophoreses, hydrolysed to determine their amino acid composition and total protein concentration, examined by scanning electron microscopy and examined on Western blots probed with a panel of antibodies directed against salivary proteins. On Coomassie Brilliant Blue stained gels, the banding pattern of whole saliva and micelles was similar but the intensity of bands was quite different. Amino acid analysis confirmed that the amino acid composition of micelles was distinct from that of whole saliva. Scanning electron microscopy showed that micelles exhibit a complex pattern consisting of individual particles or clusters of particles with different sizes and shapes. Micelles contain proteins with high (MG2 and secretory IgA), intermediate (lactoferrin, amylase and glycosylated proline-rich protein (PRP)) and low (lysozyme) molecular weight that were immuno-detected on blots probed with specific antibodies. Micelles represent particulate multicomponent structures in whole saliva that contain a subset of salivary proteins known to be important components of the innate immune system and are likely to play an important role in the maintenance of homeostasis in the oral environment. 相似文献
100.
目的:探讨PCNA、Bcl-2蛋白在粘液表皮样癌中的表达及其相互联系。方法:对33例手术切除的粘液表皮样癌组织标本进行免疫组化染色,结果:24例粘液表皮样癌均显示PCNA阳性,低分化组的PCNA表达较高分化组高(P<0.05)。Bcl-2为弱阳性表达,高分化组的Bcl-2表达较低分化组高,二组之间的Bcl-2阳性表达水平差异显著性(P<0.05)。XFYW:PCNA与Bcl-2无明显关系。 相似文献