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   1325138篇
  免费   94421篇
  国内免费   2839篇
耳鼻咽喉   19679篇
儿科学   40067篇
妇产科学   38583篇
基础医学   185514篇
口腔科学   39716篇
临床医学   111344篇
内科学   259087篇
皮肤病学   30138篇
神经病学   105576篇
特种医学   53580篇
外国民族医学   435篇
外科学   207288篇
综合类   30944篇
一般理论   435篇
预防医学   91185篇
眼科学   31242篇
药学   99599篇
  2篇
中国医学   2946篇
肿瘤学   75038篇
  2018年   11531篇
  2015年   11739篇
  2014年   16602篇
  2013年   25156篇
  2012年   32966篇
  2011年   34814篇
  2010年   20651篇
  2009年   20154篇
  2008年   33498篇
  2007年   36619篇
  2006年   37175篇
  2005年   35949篇
  2004年   35035篇
  2003年   33982篇
  2002年   33494篇
  2001年   63518篇
  2000年   65159篇
  1999年   55020篇
  1998年   13846篇
  1997年   12605篇
  1996年   12101篇
  1995年   12129篇
  1994年   11394篇
  1992年   42705篇
  1991年   41266篇
  1990年   40515篇
  1989年   39510篇
  1988年   36925篇
  1987年   36389篇
  1986年   34871篇
  1985年   33090篇
  1984年   24781篇
  1983年   20982篇
  1982年   12605篇
  1981年   11502篇
  1980年   10706篇
  1979年   23860篇
  1978年   17012篇
  1977年   14752篇
  1976年   13304篇
  1975年   15183篇
  1974年   18016篇
  1973年   17515篇
  1972年   16769篇
  1971年   15673篇
  1970年   14858篇
  1969年   14303篇
  1968年   13429篇
  1967年   11983篇
  1966年   11240篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Spindler  L.  Alam  A.  Fathallah  N.  Rentien  A.-L.  Draullette  M.  Pommaret  E.  Thierry  M.-L.  Mituialy  A. El  Abbes  L.  Aubert  M.  Benfredj  P.  Far  E. Safa  Beaussier  H.  de Parades  V. 《Techniques in coloproctology》2022,26(2):143-146
Techniques in Coloproctology - The aim of our study was to assess the efficacy of sinus laser therapy (SiLaT) for the treatment of pilonidal disease. All adult patients treated with SiLaT in our...  相似文献   
2.

There are few published procedures for teaching athletic skills to children with autism spectrum disorder (ASD). This study used a multiple baseline across participants design to evaluate the effects of prompting, demand fading, and differential reinforcement, on the basketball shooting skills of four school-aged boys diagnosed with ASD. During baseline, all four boys rarely made correct and accurate baskets at the regulation height and distance for their age-group in youth basketball. Following intervention, all four boys increased their percentage of correct shots and accuracy, compared to baseline, and their shooting skills transferred to the game of “P-I-G” with peers.

  相似文献   
3.
4.
5.
Clinical Oral Investigations - To analyze differences in variation of orthodontic diagnostic measurements on lateral cephalograms reconstructed from ultra low dose-low dose (ULD-LD) cone beam...  相似文献   
6.
7.
Objective: Hepatocellular carcinoma (HCC) microenvironment has been recognized as a key contributor for cancer progression, metastasis, and drug resistance. The crosstalk between tumor cells, the vascular endothelial growth factor (VEGF), and the chemokine (C-C motif) ligand 2 (CCL2) signaling networks mediates immunoinhibitory impact and facilitates tumor angiogenesis. The current investigation aimed at exploring the potent anti-cancer activity of the newly designed nano-based anti-cancer therapy comprising anti-VEGF drug, avastin (AV), and CCR2 antagonist (CR) to counteract HCC and tracking its mode of action in vivo. Methods: The prepared AV, CR, and AVCR nanoprototypes were characterized by nanoscale characterization techniques in our previous work. Here, they are applied for unearthing their anti-cancer properties / mechanisms in hepatic cancer-induced rats via analyzing protein levels and genetic expression of the elements incorporated in the angiogenesis, apoptosis, and metastasis signalling pathways. Results: The present results revealed a significant down-regulation in the angiogenesis, survival and metastasis indices along with up-regulation in the pro-apoptotic mediators upon treatment of hepatic cancer-bearing rats with the novel synthesized nanomaterials when compared with the untreated counterparts. We showed across HCC model that anti-VEGF in combination with CCR2 antagonism therapy leads to sensitization and enhanced tumor response over anti-VEGF or CCR2 antagonism monotherapy, particularly in its nanoscale formulation. Conclusion: The present approach provides new mechanistic insights into the powerful anti-hepatic cancer advantage of the novel nanoprototypes which is correlated with modulating critical signal transduction pathways implicated in tumor microenviroment such as angiogenesis, apoptosis and metastasis. This research work presents a substantial foundation for future studies focused on prohibiting cancer progression and recovery by targeting tumor microenviroment.  相似文献   
8.
9.
Clinical Oral Investigations - The aim of this study was to examine the occlusion of anterior teeth in individuals with shortened dental arch (SDA). In a case–control clinical study, 41...  相似文献   
10.

Background

While drinking alcohol, one must choose between the immediate rewarding effects and the delayed reward of a healthier lifestyle. Individuals differ in their devaluation of a delayed reward based on the time required to receive it, i.e., delay discounting (DD). Previous studies have shown that adolescents discount more steeply than adults and that steeper DD is associated with heavier alcohol use in both groups.

Methods

In a large-scale longitudinal study, we investigated whether higher rates of DD are an antecedent or a consequence of alcohol use during adolescent development. As part of the IMAGEN project, 2220 adolescents completed the Monetary Choice Questionnaire as a DD measure, the Alcohol Use Disorders Identification Test, and the Timeline Follow Back interview at ages 14, 16, 18, and 22. Bivariate latent growth curve models were applied to investigate the relationship between DD and drinking. To explore the consequences of drinking, we computed the cumulative alcohol consumption and correlated it with the development of discounting. A subsample of 221 participants completed an intertemporal choice task (iTeCh) during functional magnetic resonance imaging at ages 14, 16, and 18. Repeated-measures ANOVA was used to differentiate between high-risk and low-risk drinkers on the development of neural processing during intertemporal choices.

Results

Overall, high rates of DD at age 14 predicted a greater increase in drinking over 8 years. In contrast, on average, moderate alcohol use did not affect DD from ages 14 to 22. Of note, we found indicators for less brain activity in top-down control areas during intertemporal choices in the participants who drank more.

Conclusions

Steep DD was shown to be a predictor rather than a consequence of alcohol use in low-level drinking adolescents. Important considerations for future longitudinal studies are the sampling strategies to be used and the reliability of the assessments.
  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