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   46986篇
  免费   2995篇
  国内免费   261篇
耳鼻咽喉   403篇
儿科学   1354篇
妇产科学   1244篇
基础医学   6177篇
口腔科学   1133篇
临床医学   4604篇
内科学   10248篇
皮肤病学   905篇
神经病学   4954篇
特种医学   1551篇
外科学   6214篇
综合类   184篇
一般理论   19篇
预防医学   3526篇
眼科学   808篇
药学   2899篇
  1篇
中国医学   100篇
肿瘤学   3918篇
  2024年   53篇
  2023年   485篇
  2022年   861篇
  2021年   1860篇
  2020年   1097篇
  2019年   1543篇
  2018年   1771篇
  2017年   1235篇
  2016年   1397篇
  2015年   1609篇
  2014年   2210篇
  2013年   2759篇
  2012年   4074篇
  2011年   4075篇
  2010年   2065篇
  2009年   1932篇
  2008年   3232篇
  2007年   3141篇
  2006年   2837篇
  2005年   2792篇
  2004年   2316篇
  2003年   2084篇
  2002年   1863篇
  2001年   296篇
  2000年   202篇
  1999年   281篇
  1998年   311篇
  1997年   236篇
  1996年   201篇
  1995年   191篇
  1994年   166篇
  1993年   132篇
  1992年   112篇
  1991年   112篇
  1990年   97篇
  1989年   54篇
  1988年   54篇
  1987年   44篇
  1986年   42篇
  1985年   48篇
  1984年   53篇
  1983年   28篇
  1982年   44篇
  1981年   29篇
  1980年   27篇
  1979年   18篇
  1978年   20篇
  1977年   16篇
  1976年   16篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
1.
Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid malignancy with high mortality rate. This malignancy arises in thyroid follicular cells either denovo or with an associated differentiated thyroid carcinoma component. Clinically, it usually presents as a rapidly enlarging mass, pain and locally compressive symptoms. Histopathologic variability and heterogeneity often pose diagnostic challenges, especially in scant and paucicellular specimens. This article describes the clinical, histopathologic and molecular features of ATC and also addresses the associated diagnostic limitations and challenges.  相似文献   
2.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
3.
Context: Treatment of primary spinal syringomyelia is still controversial. Among others, shunting syrinx fluid to the subarachnoid, peritoneal or pleural space has been utilized with varying success. Shunt obstruction, migration, and infection represent the most common complications of these procedures.

Findings: The authors present the case of an 81-year-old woman who developed an unusual neurological deterioration resembling a subacute posttraumatic ascending myelopathy (SPAM) after the insertion of a syringosubarachnoid shunt for the treatment of slow-growing D10 syringomyelia.

Conclusion/Clinical Relevance: To date, no cases of SPAM secondary to the insertion of a syringosubarachnoid shunt for the treatment of syringomyelia have been reported. The potential pathogenesis related to this phenomenon is discussed.  相似文献   
4.
The present study aimed at measuring seropositivities for infection by Ascaris suum and Toxocara canis using the excretory/secretory (E/S) antigens from Ascaris suum (AES) and Toxocara canis (TES) within an indigenous population. In addition, quantification of cytokine expressions in peripheral blood cells was determined. A total of 50 Warao indigenous were included; of which 43 were adults and seven children. In adults, 44.1% were seropositive for both parasites; whereas children had only seropositivity to one or the other helminth. For ascariosis, the percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%, respectively. While that for toxocariosis, the percentage of TES seropositivity in adults and children was low; 9.3% and 14.3%, respectively. The percentage of seronegativity was comparable for AES and TES antigens in adults (27.9%) and children (28.6%). When positive sera were analyzed by Western blotting technique using AES antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9, 98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that Blastocystis hominis, Hymenolepis nana and Entamoeba coli were the most commonly observed intestinal parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and IL-4 expressions showed that there was only a significant increased expression of IL-4 in indigenous with TES seropositivity (p < 0.002). Ascaris and Toxocara seropositivity was prevalent among Warao indigenous.  相似文献   
5.
6.
7.
8.
9.
10.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  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