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   75215篇
  免费   7472篇
  国内免费   2310篇
耳鼻咽喉   377篇
儿科学   1140篇
妇产科学   1688篇
基础医学   10472篇
口腔科学   1977篇
临床医学   6786篇
内科学   8105篇
皮肤病学   1424篇
神经病学   4204篇
特种医学   1204篇
外国民族医学   20篇
外科学   3957篇
综合类   11692篇
现状与发展   13篇
一般理论   20篇
预防医学   6961篇
眼科学   1318篇
药学   15481篇
  47篇
中国医学   4117篇
肿瘤学   3994篇
  2024年   148篇
  2023年   1067篇
  2022年   1887篇
  2021年   2799篇
  2020年   2782篇
  2019年   2889篇
  2018年   2575篇
  2017年   2886篇
  2016年   2736篇
  2015年   2638篇
  2014年   4714篇
  2013年   7222篇
  2012年   4492篇
  2011年   4826篇
  2010年   4104篇
  2009年   3463篇
  2008年   3248篇
  2007年   3341篇
  2006年   3061篇
  2005年   2731篇
  2004年   2402篇
  2003年   2125篇
  2002年   1809篇
  2001年   1648篇
  2000年   1396篇
  1999年   1209篇
  1998年   1136篇
  1997年   1059篇
  1996年   945篇
  1995年   876篇
  1994年   760篇
  1993年   737篇
  1992年   689篇
  1991年   630篇
  1990年   451篇
  1989年   426篇
  1988年   359篇
  1987年   274篇
  1986年   262篇
  1985年   422篇
  1984年   356篇
  1983年   240篇
  1982年   269篇
  1981年   216篇
  1980年   166篇
  1979年   107篇
  1978年   112篇
  1977年   70篇
  1976年   78篇
  1975年   40篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Obtaining accurate assessment data from adolescents in treatment aids clinical decision making and facilitates more accurate outcome evaluations. However, findings could be biased due to underreported substance use and mental health symptoms. This article compares self-reports of youth in non-White matched client–assessor dyads and those in nonmatched dyads. There were no differences on self-reported substance use, but matched youth reported significantly fewer attention deficit/hyperactivity disorder symptoms versus the comparison group. One possible reason for these findings is the effect of in-group stereotype threat. Future studies should examine the potential effect that in-group stereotyping and perceived racism have on the therapeutic relationship.  相似文献   
32.
Classical Kaposi sarcoma (KS) usually appears on lower extremities accompanied or preceded by local lymphedema. However, the development in areas of chronic lymphedema of the arms following mastectomy, mimicking a Stewart–Treves syndrome, has rarely been described. We report an 81‐year‐old woman who developed multiple, erythematous to purple tumors, located on areas of post mastectomy lymphedema. Histopathological examination evidenced several dermal nodules formed by spindle‐shaped cells that delimitated slit‐like vascular spaces with some red cell extravasation. Immunohistochemically, the human herpesvirus type 8 (HHV‐8) latent nuclear antigen‐1 was detected in the nuclei of most tumoral cells confirming the diagnosis of KS. Lymphedema could promote the development of certain tumors by altering immunocompetence. Although angiosarcoma (AS) is the most frequent neoplasia arising in the setting of chronic lymphedema, other tumors such as benign lymphangiomatous papules (BLAP) or KS can also develop in lymphedematous limbs. It is important to establish the difference between AS and KS because their prognosis and treatment are very different. Identification by immunohistochemistry of HHV‐8 is useful for the distinction between KS and AS or BLAP.  相似文献   
33.
《Immunity》2022,55(8):1343-1353
  相似文献   
34.
35.
Background: There are some unique epidemiological characteristics of esophageal cancer in Iran. The objective of this study was finding the association between tobacco, substance and alcohol using with the risk of esophageal cancer in North Khorasan, Iran.

Methods: This Case-Control study was carried out on 96 patients with esophageal cancer and 187 controls. Controls were matched to cases by age and sex. Data were collected through structured interview. Data were analyzed by using chi-square test, T-test and logistic regression, in Stata software version 12.

Results: Our findings show Hookah smoking [OR = 6.1(CI95%:1.2–13.1)] and opium consumption [OR = 2.1(CI95%:1.2–3.5)] were associated with esophageal cancer. Cigarette and pipe smoking, age of onset of smoking, duration of smoking, number of smoking per day, leaving history of smoking, years of leaving smoking, drug withdrawal, number of times of drug withdrawal, a history of drug relapse, alcohol consumption and alcohol dose–response were not related to esophageal cancer.

Conclusion: According to our results, hookah smoking and opium consumption enhance the risk of esophageal cancer in North Khorasan of Iran. We suggest appropriate planning to prevent the esophageal cancer in this district.  相似文献   

36.
37.
38.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
39.
40.
Background: Research has demonstrated that problem behavior has been associated with substance use, but knowledge is lacking on such associations in a low-income country like Nepal. Aims: This study aimed to find associations between emotional and behavioral problems and substance use among Nepalese adolescents. Method: A cross-sectional study was conducted at the end of 2011, with participants from three schools in the Province 4 of Nepal. We selected 408 adolescents aged 12 to 18 (mean 15.2 years, 54% boys) at one urban and two rural schools. The data were collected using the Youth Self-Report and Adolescents’ Substance Use Measurement. Results: Higher scores on withdrawn/depressed symptoms, thought problems, attention problems, delinquent or aggressive behavior or internalizing or externalizing problems were associated with the use of tobacco, alcohol or other substances. In the broadband scales, only internalizing problems predicted the use of intoxicants. Higher scores for attention problems predicted the use of tobacco, any intoxicants, and high-risk user. Conclusion: Our findings indicated that problem behavior among Nepalese adolescents was associated with substance use. Future studies should explore the association between problem behavior and substance use, including causal factors, so that risky behavior among Nepalese adolescents can be prevented.  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