全文获取类型
收费全文 | 4999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 | 281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 | 347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 | 1058篇 |
出版年
2024年 | 11篇 |
2023年 | 47篇 |
2022年 | 82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5851条查询结果,搜索用时 31 毫秒
11.
Endoscopic ultrasound (EUS) is sensitive for staging gastrointestinal malignancies and pancreatic lesions. EUS‐fine‐needle aspiration (EUS‐FNA) offers a diagnostic accuracy of about 60–90% for pancreatic tumors and > 90% for lymph nodes. There are several limitations of EUS‐FNA including the need for on‐site cytopathology review. In addition, accuracy of cytologic review is hampered by the presence of blood, benign epithelial cells, desmoplasia, and well‐differentiated tumors. Furthermore, the small biopsy sample and destruction of tissue architecture limits the diagnostic sensitivity for GISTs and lymphomas. Many of these problems can be overcome with use of EUS trucut biopsy (TCB) needles. These large caliber, cutting needles acquire larger tissue samples allowing preservation of tissue architecture and histologic examination. Our recently described experience with EUS‐TCB initially in swine and later humans demonstrated the safety for acquiring histologic tissue representative of the target organs sampled enabling accurate diagnosis. These studies suggested greater diagnostic accuracy of EUS‐TCB for submucosal mass lesions and lymphoma and potentially the need for fewer needle passes for solid pancreatic neoplasms. In this paper we will review the current TCB literature, device design and technique, help troubleshoot potential problems, and offer opinion as to the utility and role of this new device. 相似文献
12.
K Alderson 《Muscle & nerve》1992,15(11):1284-1289
The presence, morphology, distribution, and abundance of axonal swellings in intramuscular nerves were evaluated. Axonal swellings were present in intramuscular nerves in 42% of 127 muscle biopsies from patients with a variety of conditions. The incidence was highest in muscle from patients with peripheral neuropathy, but swellings were present in muscle from patients with motor neuron disease, primary muscle diseases, and some individuals without clinical or histological evidence of neuromuscular disease. The greatest number of swellings in intramuscular nerves was in muscle from patients with chronic inflammatory demyelinating neuropathy. Swellings were spherical or elliptical, 4-20 microns in diameter, 5-30 microns in length, and composed of neurofilaments. Swellings were present only in myelinated axons of intramuscular nerves, proximal to nodes of Ranvier or in internodal regions. Swellings were not associated with axonal degeneration. They were probably not transported. The formation or accumulation of swellings may reflect altered axonal dynamics common to a number of disease processes. 相似文献
13.
372���Ǽ��Լ�״��������������� 总被引:14,自引:0,他引:14
目的 探讨辅助检查在诊断亚急性甲状腺炎中的作用。方法 回顾分析372例亚急性甲状腺炎病人所做的各项辅助检查结果。结果 血沉,B超,彩色多普勒,甲状腺核素扫描,甲状腺吸^131I率测定,细针穿刺细胞学,TMA,TGA等项检查诊断本病的阳性率分别为93.75%,81.63%,95.62%,89.66%,69.70%,89.41%,13.46%和9.62%。T3,T4,TSH检查结果随着病程的进展变化较大。结论 血沉检查对诊断本病缺乏特异性;彩色多普勒,细针穿刺细胞学检查诊断率高,特异性强,是首选的检查手段;甲状腺核素扫描可以准确地反映甲状腺功能状态;检测血清中T3,T4,TSH水平可以协助诊断本病,判断疾病所处时期。 相似文献
14.
Granulocytic sarcoma (GS) is a localized tumour of immature granulocytes that is usually associated with myelogenous leukaemia. We report an unusual case of mastoid GS with meningeal extension but no bone marrow involvement on presentation. Histological examination of the surgical specimen and the characteristic cerebrospinal fluid (CSF) cytology showing cytoplasmic granulations and Auer bodies led to the diagnosis of GS. Positive cytochemical staining of the immature CSF cells for naphtol-ASD chloroacetate esterase and myeloperoxidase confirmed their myeloid origin. Immunophenotyping did not reveal common acute lymphoblastic leukaemia antigen, cytokeratin, T or B-cell antigens. The patient underwent surgical resection of the localized tumour, followed by radiation therapy, intrathecal and systemic chemotherapy, as if he had acute myelogenous leukaemia (AML). He did not develop AML in the 21 months after the tumour resection. This case emphasizes the value of CSF cytological examination of tumour cells and the use of an immumocytochemical marker for differentiating GS from malignant lymphoma. 相似文献
15.
Clear-cell lesions of the parotid gland are uncommon but when studied by fine-needle aspiration may result in a clinically important but cytologically difficult differential diagnosis. Clear-cell lesions involving the parotid include acinic cell neoplasm, clear cell oncocytoma, mucoepidermoid carcinoma, primary clear-cell carcinoma, epithelial-myoepithelial carcinoma, and metastatic renal cell carcinoma. Accurate diagnosis is achieved by assessment of nuclear features, other cell populations present, and clinical data including radiographic studies. 相似文献
16.
Bhattacharya B Sariya D Reddy VB Kluskens L Gould VE Gattuso P 《Diagnostic cytopathology》2002,26(6):384-386
A 4(1/2)-yr-old female presented with right-sided pleural effusion and a retroperitoneal mass. Cytologic analysis of the pleural fluid yielded malignant small round blue cells, which were noncohesive, 3-4 times the size of lymphocytes. The malignant cells had hyperchromatic, pleomorphic nuclei with moderate amounts of vacuolated cytoplasm. A few fiber-shaped cells were also seen. Immunostains for desmin, muscle-specific actin were positive; ultrastructural findings of thick and thin actin-myosin filaments confirmed the diagnosis of embryonal rhabdomyosarcoma. This case illustrates the importance of performing appropriate immunohistochemical stains and ultrastructural studies on cytological material to arrive at a definitive diagnosis. 相似文献
17.
Cappelli C Tironi A Mattanza C Cumetti D Agosti B Gandossi E Pirola I De Martino E Cherubini L Micheletti L Castellano M Rosei EA 《Endocrine pathology》2005,16(4):349-354
Objective: To compare the cytological findings of hypoechoic thyroid nodules with intranodular vascular pattern (pattern II) obtained
by two different needles (Neolus 25 gauge, Chemil, Wenzhou, China vs Yale Spinal 25 gauge, Becton Dickinson, Madrid, Spain)
in euthyroid patients and to evaluate their cost-effectiveness.
Methods: From January 2001 to December 2003, 480 euthyroid patients with a hypoechoic thyroid nodule pattern II were referred for
US-FNAC. The nodules were alternatively evaluated by Neolus or by Yale Spinal with the stylet (YS+) or without the stylet
(YS−), in order to evaluate if the cytological results could be due to the presence of the stylet or to the different length
of the two needles. For each nodule two passes were performed and the material was obtained by capillary action. Material
was smeared on slides, fixed, and stained by Papanicolaou techniques. Cytological specimens were evaluated in blind by the
same experienced cytopathologist.
Results: Inadequate cytological specimens because of blood contamination were present in 30 (18.7%) samples by Neolus needle and in
22 (13.8%) by YS− compared to only 5 (3.1%) by YS+. In 6 (20%) cases of the 30 repeated US-FNAC by Neolus and in 4 (18%) of
the 22 US-FNAC by YS−, material remained inadequate for diagnosis because of blood contamination. All the five repeated samples
obtained by YS+ became adequate for diagnosis and resulted benign nodules. Direct costs of US-FNAC procedure are currently
Э 72.30 including cytological examination. The cost of Neolus and Yale needles is Э 0.19 and Э 3.0, respectively. The estimated
total cost to obtain a cytological diagnosis by a Neolus needle (160 + 30 repeated US-FNAC) was Э 13809.2 vs Э 12919.5 by
Yale Spinal needle (160 + 5 repeated US-FNAC).
Conclusion: This study demonstrates that the use of Yale Spinal needles greatly reduces inadequate cytological specimens, and therefore
limits both direct and indirect costs. 相似文献
18.
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
19.
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
20.
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