首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5004篇
  免费   690篇
  国内免费   170篇
耳鼻咽喉   48篇
儿科学   38篇
妇产科学   179篇
基础医学   2174篇
口腔科学   62篇
临床医学   281篇
内科学   317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   192篇
眼科学   167篇
药学   131篇
中国医学   34篇
肿瘤学   1063篇
  2024年   12篇
  2023年   50篇
  2022年   84篇
  2021年   155篇
  2020年   183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   278篇
  2009年   284篇
  2008年   248篇
  2007年   243篇
  2006年   231篇
  2005年   194篇
  2004年   199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5864条查询结果,搜索用时 15 毫秒
51.
The diagnostic cytomorphologic findings in a case of elastofibroma dorsi are described in this report. The correct diagnosis was initially overlooked on fine-needle aspiration, and was subsequently made by open biopsy. Review of the FNA material, however, demonstrated scanty but diagnostic material. Cytologic examination revealed a mixture of fibroblasts, adipose tissue, and swollen lightly staining cyanophilic elastic fibers in a background of collagenous matrix. Cross sections of the elastic fibers had the typical serrated and globular appearance. These fibers stained positive with elastin stains. The cytomorphology of elastofibroma dorsi with diagnostic pitfalls and differential diagnostic dilemmas are discussed in this article. © 1994 Wiley-Liss, Inc.  相似文献   
52.
Isolated primary amyloid tumor of bone is rare; however, preoperative diagnosis can be rewarding because the prognosis is excellent. There are no clinical or roentgenographic criteria that can establish this diagnosis. There are few previous reports of fine-needle aspiration (FNA) where diagnosis of amyloidoma was made retrospectively. They describe the presence of extracellular hyaline material along with plasma cells and lymphocytes. A 35-year-old female was referred to the FNA clinic with swelling in the right upper chest wall. Radiologic findings revealed a destructive lytic lesion involving the bodies of D1 and D2 vertebrae with extension into surrounding soft tissue. Repeated FNA smears were hypocellular but had abundant homogeneous flocculent material, which stained positive with Congo red. A few plasma cells and foreign-body giant cells were also seen. We conclude that preoperative FNA cytology diagnosis of amyloid tumor is possible. Hypocellular smears with flocculent material, plasma cells, and foreign-body giant cells in absence of granulation tissue should suggest the diagnosis.  相似文献   
53.
To evaluate the accuracy and reproducibility of subgrouping and grading soft-tissue sarcomas by fine-needle aspiration biopsy (FNAB), a blind review was conducted of 84 FNAB specimens from 77 malignant and 7 benign soft-tissue lesions. Cytomorphologic subgroups included 31 spindle-cell, 24 pleomorphic, 11 myxoid, 7 epithelioid/polygonal, 3 small round cell, and 8 nondiagnostic cases. Malignancies included one lymphoma and 41 primary, 15 recurrent, and 20 metastatic soft-tissue sarcomas. Adequacy was defined as a majority of slides with at least 5 clusters of 10 unobscured cells. Five originally false-negative cases were considered nondiagnostic on review. Sarcoma was recognized in 59 of 64 adequate cases (92%) with available histology; however, the specific histopathologic subtype was identified in only 9 cases (14%). Benign myxoid and spindle-cell lesions were difficult to separate from low-grade sarcomas in 4 cases, and a B-cell lymphoma with sclerosis mimicked a low-grade myxoid sarcoma. The assigned cytologic grade accurately reflected the histologic grade in 90% of sarcomas when segregated into high and low grades. Pleomorphic, small round cell, and epithelioid/polygonal subgroups corresponded to high-grade sarcomas in all cases with only minor noncorrelations. Major grading noncorrelations occurred in 50% of myxoid and 9% of spindle-cell sarcomas. Therefore, attention should be given to specimen adequacy, and caution should be exercised when attempting to grade myxoid and spindle-cell sarcomas by FNAB.  相似文献   
54.
The diagnostic category of atypical glandular cells (AGC) in the Bethesda system for the reporting of cervicovaginal cytology has undergone significant modification since its inception in 1988. More than a decade later, this category remains a diagnostic challenge to both clinicians and cytopathologists because of the lack of uniform cytologic criteria, the lack of interobserver agreement in the diagnosis, and the lack of standardized patient management guidelines. This article reviews the current classification of AGC in the Bethesda system, the cytomorphologic features and differential diagnosis, the clinical significance of a diagnosis of AGC, and the clinical management of patients with AGC. This article provides a comprehensive clinicopathologic review of the category of AGC.  相似文献   
55.
BackgroundCurrent data regarding the risk of malignancy in a large thyroid nodule with benign fine-needle aspiration biopsy(FNAB) is conflicting. We investigated the impact of patient age on the risk of malignancy in nodules≥4 cm with benign cytology.MethodsWe performed a single-institution retrospective review of patients who underwent surgery from 07/2008–08/2019 for a cytologically benign thyroid nodule ≥4 cm. The relationship between malignant histopathology and patient and ultrasound features was assessed with multivariable logistic regression.ResultsOf 474 nodules identified, 25(5.3%) were malignant on final pathology. In patients <55 years old, 21/273(7.7%) nodules were malignant, compared to 4/201(2.0%) in patients ≥55. Patient age ≥55 was independently associated with significantly lower risk of malignancy(OR:0.2,95%CI:0.1–0.7,p = 0.011). Increasing nodule size >4 cm and high-risk ultrasound features were not associated with risk of malignancy(OR:1.0,95%CI:0.7–1.4,p = 0.980, and OR:9.6,95%CI:0.9–107.8,p = 0.066, respectively).ConclusionsPatients <55 years old are 3.7-fold more likely to have a falsely benign FNA biopsy in a nodule≥4 cm.  相似文献   
56.
57.
Diagnosis of metastatic lesions to the stomach by salvage cytology   总被引:1,自引:0,他引:1  
Summary Secondary neoplasms of the stomach are rare and are often clinical and diagnostic problems. Three patients with bleeding volcano-like ulcers were diagnosed by combined endoscopic salvage cytology and surgical biopsy as having metastatic submucosal lesions from hematologic spread. The combination of endoscopic appearance, clinical findings, and tissue and cytologic examination can lead to the correct diagnosis. The results from these cases support the utility of this cytologic technique in combination with biopsy in this clinical setting.  相似文献   
58.
郭启煜  高妍  丛琳  邵宁生 《医学争鸣》2001,22(14):1307-1310
目的 探讨游离脂肪酸是否会对大鼠骨骼肌细胞L eptin受体的基因、蛋白表达及酪氨酸磷酸化产生一定的影响 ,进而导致胰岛素抵抗及葡萄糖代谢的异常 .方法 分离、培养新生 Sprague- Dawley大鼠骨骼肌细胞 ,分别与软脂酸(0 .2 5 m mol· L- 1 )或油酸 (0 .12 5 mmol· L- 1 )孵育 12 ,2 4和36 h,提取蛋白后用 Western印迹法检测 L eptin受体的蛋白水平 .用 RT- PCR检测胰岛细胞内 L eptin受体 RNA含量的变化 .应用免疫沉淀法检测 L eptin受体的酪氨酸磷酸化程度 .结果 软脂酸和油酸孵育后大鼠骨骼肌细胞 L eptin受体的蛋白表达水平在孵育 12和 2 4h后同对照组相比无显著变化 ,在孵育 36 h后同对照组相比显著下调 [软脂酸 (0 .36±0 .0 3)和油酸 (0 .35± 0 .0 4) vs对照 (0 . 39± 0 .0 5 ) ,P<0 .0 5 ];L eptin受体的 RNA水平在孵育 12 h后同对照组相比无显著变化 ,孵育 2 4和 36 h 后显著下调 [2 4h:软脂酸(0 .2 6± 0 .0 3)和油酸 (0 .2 6± 0 .0 4) vs对照 (0 .31± 0 .0 3) ,P<0 .0 5 ;36 h:软脂酸 (0 .2 5± 0 .0 4)和油酸 (0 .2 3± 0 .0 3) vs对照 (0 .2 9± 0 .0 1) ,P<0 .0 5 ];L eptin受体的酪氨酸磷酸化程度在在孵育 12 h后同对照组相比无显著变化 ,孵育 2 4和36 h后显著下调 [2 4h:软脂酸  相似文献   
59.
道诺霉素抑制视网膜色素上皮细胞炎前因子的表达   总被引:1,自引:1,他引:0  
目的 观察道诺霉素对视网膜色素上皮细胞细胞(RPE)炎前因子表达的影响 .方法 培养的人 RPE经 IL- 1β(10μg· L- 1 )刺激以及不同浓度的道诺霉素作用后 ,用EL ISA、免疫组化和原位杂交等方法 ,检测培养的人 RPE炎前因子 m RNA和蛋白质的表达 .结果  EL ISA显示对照组培养 RPE在 IL- 1β刺激 8h后 ,上清中 IL- 6与 IL- 8分别为2 0 0 0 pg· m L- 1· 10 - 6 cells和 5 0 0 0 pg· m L- 1· 10 - 6 cells.使用 10 0 μg·L- 1 道诺霉素作用于培养的 RPE后 IL- 6与 IL-8分别为 180 pg· m L- 1 · 10 - 6 cells (P <0 .0 1)和 32 0pg· m L- 1· 10 - 6 cells(P<0 .0 1) .免疫组化和原位杂交亦显示不同浓度道诺霉素可以不同程度地抑制 RPE内炎前因子蛋白质与 m RNA的表达 .结论 道诺霉素能有效地抑制 IL -1β诱导的培养的 RPE IL - 6和 IL - 8的表达  相似文献   
60.
Undifferentiated carcinoma with osteoclast-like giant cells, also formerly known as osteoclast-like giantcell tumor, is a rare neoplasm of the pancreas and usually diagnosed after pancreatectomy. The presence of non-neoplastic osteoclast-like giant cells is the histological hallmark of this tumor and the diagnosis is usually not difficult on tissue sections. However there have been relatively few reports regarding the cytological features of this type of tumor in literatures.1-4 Here we.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号