全文获取类型
收费全文 | 4994篇 |
免费 | 682篇 |
国内免费 | 170篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 38篇 |
妇产科学 | 178篇 |
基础医学 | 2173篇 |
口腔科学 | 62篇 |
临床医学 | 279篇 |
内科学 | 316篇 |
皮肤病学 | 25篇 |
神经病学 | 79篇 |
特种医学 | 54篇 |
外国民族医学 | 4篇 |
外科学 | 346篇 |
综合类 | 669篇 |
预防医学 | 187篇 |
眼科学 | 167篇 |
药学 | 131篇 |
中国医学 | 34篇 |
肿瘤学 | 1056篇 |
出版年
2024年 | 11篇 |
2023年 | 47篇 |
2022年 | 77篇 |
2021年 | 154篇 |
2020年 | 181篇 |
2019年 | 215篇 |
2018年 | 156篇 |
2017年 | 226篇 |
2016年 | 237篇 |
2015年 | 229篇 |
2014年 | 323篇 |
2013年 | 322篇 |
2012年 | 287篇 |
2011年 | 302篇 |
2010年 | 276篇 |
2009年 | 284篇 |
2008年 | 247篇 |
2007年 | 243篇 |
2006年 | 231篇 |
2005年 | 194篇 |
2004年 | 198篇 |
2003年 | 169篇 |
2002年 | 164篇 |
2001年 | 117篇 |
2000年 | 44篇 |
1999年 | 56篇 |
1998年 | 144篇 |
1997年 | 117篇 |
1996年 | 90篇 |
1995年 | 53篇 |
1994年 | 40篇 |
1993年 | 46篇 |
1992年 | 35篇 |
1991年 | 43篇 |
1990年 | 34篇 |
1989年 | 30篇 |
1988年 | 36篇 |
1987年 | 37篇 |
1986年 | 35篇 |
1985年 | 32篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 4篇 |
排序方式: 共有5846条查询结果,搜索用时 171 毫秒
21.
Elastofibroma dorsi (EFD) is a relatively rare soft tissue mass, probably of reactive nature. The lesion is typically located near the inferior margin of the scapula or between the inferior part of scapula and the chest wall in elderly women. Although location of the tumor together with the age/sex of the patients and radiologic findings is often suggestive of the diagnosis, tissue examination has been considered necessary to confirm the diagnosis. Although the histologic features of EFD are well known, there are only four single case reports of the cytologic findings in the English language literature. We describe the cytologic features of EFD in five patients with correlations to clinical, radiologic, histologic, and electron microscopic findings. The current study suggests that the fine-needle aspiration (FNA) features are highly diagnostic, permitting a firm diagnosis of EFD in a typical clinical setting and eliminating the need for preoperative histologic examination. 相似文献
22.
A new micropore membrane assay for leukocyte migration has been devised. It permits the complete retrieval in monodisperse suspension of functionally intact cells that have traversed the membrane, thus allowing the application of precise, automated techniques, including flow cytometry and electronic particle counting. Hemocytometers may also be used. Direct comparison with 2 different conventional membrane methods showed that the new method performed superiorly. It was also much more economical with regard to time and labor. This technique permitted detection of functional differences between leukocytes isolated from blood in different ways. Data on the duration of concentration gradients in chemotaxis chambers are also presented. 相似文献
23.
We have studied 3 cases of sarcoidosis involving the parotid gland by means of fine-needle aspiration cytology (FNAC). The main findings were noncaseating granulomas, multinucleated giant cells (MGCs), and lymphocytes. In one case MGCs contained asteroid bodies and in another case we observed calcium oxalate crystals (COCs) over both stromal fragments and MGCs. Although nonpathognomonic for sarcoidosis, these 2 findings may help in the diagnosis of this condition. However, both are easily overlooked and must be borne in mind when viewing noncaseating granulomas. Sarcoid granulomas displaying COC must be differentiated from foreign-body granulomas. The aforementioned cytological findings must be assessed in conjunction with clinical findings. Nevertheless, in most cases the diagnosis of sarcoidosis is made by exclusion. 相似文献
24.
Rhabdomyoblasts demonstrating immunoreactivity for muscle-specific actin, desmin, and myoglobin were identified in smears obtained by aspiration from a large retroperitoneal mass in a 14-mo-old girl. Following a tentative diagnosis of a rhabdomyogenous neoplasm, retroperitoneal exploration and adrenalectomy demonstrated a stromal poor neuroblastoma with extensive rhabdomyogenous differentiation. The presence of a subpopulation of rhabdomyoblasts was not diagnostic of rhabdomyosarcoma when obtained by fine-needle aspiration from a retroperitoneal tumor composed predominantly of primitive small round cells. 相似文献
25.
C. Garcia Castro J. M. Gonzalez-Posada V. Castro Lopez-Tarruella E. C. Salido Ruiz 《Diagnostic cytopathology》1993,9(2):174-178
We have analyzed 245 transplant aspirative cytologies (TACs) from 96 renal allograft patients. TACs were divided in two chronological groups: Early (TACs performed during the first 3-mo post-transplantation) and late (TACs performed after the third month post-transplantation), in order to assess the effect of allograft tolerance on TAC features. Both morphological and immunocytochemical aspects were evaluated, including CD4, CD8, IL2-R, and HLA-DR immunolabeling. A final diagnosis for each case of allograft dysfunction was achieved by other independent diagnostic means. Four diagnostic groups were considered in the present study: acute rejection (AR), chronic rejection (CR), acute tubular necrosis (ATN), and Cyclosporin A toxicity (CsA-T). In addition, a control group (C) was established from patients with stable allograft function. We found that immunocytochemical analysis of TACs is particularly helpful in the diagnosis of late allograft dysfunction, a time period when the simple cytological study of renal infiltrate is not informative enough to help take therapeutic decisions. 相似文献
26.
Epithelioid variant of gastrointestinal stromal tumor: Diagnosis by fine-needle aspiration 总被引:1,自引:0,他引:1
Epithelioid gastrointestinal stromal tumors (GISTs) may cause significant diagnostic confusion on fine-needle aspiration (FNA) with carcinomas, neuroendocrine tumors, and melanoma, particularly when metastatic. This study characterizes the cytologic features of nine cases of epithelioid GISTs that were obtained by computerized tomographic guidance in five, by endoscopic ultrasound in three, and from an excised liver tumor in one. Six cases presented as liver masses, one as a perisplenic mass, one as an abdominal mass, and one as a gastric mass. The aspirates revealed mainly single or small clusters of epithelioid cells with a moderate amount of granular to clear cytoplasm, small uniform nuclei with mild to marked nuclear envelope irregularities. Binucleation and intranuclear inclusions were frequent findings. Collagenous stroma was seen in most cases. In three cases, a neuroendocrine tumor was the initial diagnosis. Immunocytochemical staining for c-kit (CD117) was performed on cellblocks in six cases and was positive in five cases. On the subsequent surgical specimen, CD117 was positive in the c-kit-negative cytology case. The diagnosis of GIST should be considered in aspirates of the gastrointestinal tract, liver, mesentery, or abdominal wall mass lesions when epithelioid cells are the predominant cell type. Ancillary studies such as immunohistochemical stains are usually helpful in making a definitive diagnosis. 相似文献
27.
Immunostaining of galectin-3 and CD44v6 using fine-needle aspiration for distinguishing follicular carcinoma from adenoma 总被引:4,自引:0,他引:4
To evaluate the clinical applicability of galectin-3 and CD44 variant 6 (CD44v6) immunostaining in fine-needle aspiration cytology (FNAC) of thyroid follicular tumors, 79 cytological specimens (35 follicular carcinomas and 44 follicular adenomas) were studied. The positive rates of galectin-3 and CD44v6 were 89 and 74% in follicular carcinoma, respectively, and 25 and 30% in follicular adenoma, respectively. There were no significant correlations between the expression of galectin-3 or CD44v6 in follicular carcinoma and characteristics such as capsular invasion, vascular invasion, metastasis, or tumor size. Positive staining of either galectin-3 or CD44v6 resulted in a diagnostic sensitivity of 97% and a specificity of 52% for follicular carcinoma among follicular tumors. Immunostaining of galectin-3 or CD44v6 using cytological specimens can provide independent information on conventional morphological findings of cytology to distinguish follicular carcinoma from adenoma. 相似文献
28.
Fine-needle aspiration (FNA) cytology and immunophenotyping by flow cytometry (FCM) are increasingly being used for diagnosing and subclassifying lymphoma in the REAL/WHO classification. Herein, we report a case of primary mediastinal large B-cell lymphoma (PMBL), a subtype of diffuse large B-cell lymphoma in the WHO classification, diagnosed by FNA cytology in conjunction with FCM. This, to our knowledge, has not previously been reported. A 57-yr-old woman presented with bilateral axillary lymphadenopathy and intermittent shortness of breath. CT scan revealed a 5-cm anterior mediastinal mass and mediastinal lymphadenopathy. Endoscopic ultrasound-guided FNA of a 4.5-cm subcarinal lymph node showed medium to large atypical lymphocytes with scant to moderate finely vacuolated cytoplasm. Nuclei were enlarged, cleaved, noncleaved, lobulated, and hyperchromatic. The background showed lymphoglandular bodies. Malignant large cell lymphoma was cytologically diagnosed. FCM, performed on a portion of the FNA specimen, demonstrated large B cells devoid of surface immunoglobulin expression, the characteristic immunophenotype of PMBL. The histologic diagnosis was PMBL. Touch-imprint cytology of the histologic specimen showed large cells with a narrow rim of clear cytoplasm and prominent outer cell border. Nuclear features were similar to the FNA specimen. In the presence of a mediastinal mass, FNA cytology in conjunction with FCM can effectively diagnose PMBL in the appropriate clinical setting. 相似文献
29.
目的 探讨高危型人乳头状瘤病毒(hish-risk human papillomavirus,HR-HPV)和宫颈细胞学联合检测在诊断宫颈病变中的临床价值.方法 对2004年10月至2006年12月北京大学第一医院就诊的患者进行HR-HPV检测和宫颈细胞学检查,对一项或两项结果异常者均行阴道镜下宫颈活检,并以宫颈活检结果为金标准,比较HR-HPV检测、宫颈细胞学检查、HR-HPV和宫颈细胞学联合检测对宫颈病变的诊断价值.结果 HR-HPV检测、宫颈细胞学检查及HR-HPV检测联合宫颈细胞学检查对诊断宫颈病变有不同价值.HR-HPV检测筛查CINⅡ、CINⅢ的敏感度、特异度、阳性预测值和阴性预测值分别为94.83%、31.06%、55.22%、87.02%,宫颈细胞学筛查CINⅡ、CINⅢ的敏感度、特异度、阳性预测值和阴性预测值分别为92.10%、31.06%、54.50%、81.43%,HR-HPV和宫颈细胞学联合检测筛查CINⅡ、CINⅢ的敏感度、特异度、阳性预测值和阴性预测值分别为99.65%、18.55%、61.46%、97.62%.结论 采用HR-HPV和宫颈细胞学联合检测可提高宫颈病变的检出率,并可指导临床医生对宫颈病变的治疗. 相似文献
30.
Ameloblastic fibroma of the jaw is a rare, benign mixed odontogenic tumor, having little tendency for local invasion and a low recurrence rate. Cytologic distinction from ameloblastoma, ameloblastic fibrosarcoma, and intraosseous adenoid cystic carcinoma is necessary, in view of the different biologic behavior. A painful, slow-growing swelling of the jaw in a 5-yr-old child clinicoradiologically considered as a benign cystic lesion was aspirated. Sheets of small monomorphic epithelial cells with peripheral palisading by columnar cells were seen on cytology smears. The striking feature was central hyaline globules in some tubules. A cytologic possibility of adenomatoid odontogenic tumor was suggested. Histopathology, however, confirmed it to be an ameloblastic fibroma. 相似文献