全文获取类型
收费全文 | 1366篇 |
免费 | 96篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 43篇 |
妇产科学 | 14篇 |
基础医学 | 205篇 |
口腔科学 | 28篇 |
临床医学 | 184篇 |
内科学 | 225篇 |
皮肤病学 | 20篇 |
神经病学 | 162篇 |
特种医学 | 20篇 |
外科学 | 141篇 |
综合类 | 9篇 |
一般理论 | 4篇 |
预防医学 | 224篇 |
眼科学 | 14篇 |
药学 | 103篇 |
中国医学 | 1篇 |
肿瘤学 | 65篇 |
出版年
2024年 | 4篇 |
2023年 | 24篇 |
2022年 | 52篇 |
2021年 | 98篇 |
2020年 | 59篇 |
2019年 | 75篇 |
2018年 | 68篇 |
2017年 | 50篇 |
2016年 | 49篇 |
2015年 | 60篇 |
2014年 | 65篇 |
2013年 | 66篇 |
2012年 | 135篇 |
2011年 | 141篇 |
2010年 | 63篇 |
2009年 | 41篇 |
2008年 | 93篇 |
2007年 | 64篇 |
2006年 | 75篇 |
2005年 | 63篇 |
2004年 | 38篇 |
2003年 | 34篇 |
2002年 | 20篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1982年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1465条查询结果,搜索用时 15 毫秒
121.
Rodrigo A. España Erik B. Oleson Jason L. Locke Bethany R. Brookshire David C. S. Roberts Sara R. Jones 《The European journal of neuroscience》2010,31(2):336-348
Recent evidence suggests that the hypocretin–orexin system participates in the regulation of reinforcement processes. The current studies examined the extent to which hypocretin neurotransmission regulates behavioral and neurochemical responses to cocaine, and behavioral responses to food reinforcement. These studies used a combination of fixed ratio, discrete trials, progressive ratio and threshold self‐administration procedures to assess whether the hypocretin 1 receptor antagonist, SB‐334867, reduces cocaine self‐administration in rats. Progressive ratio sucrose self‐administration procedures were also used to assess the extent to which SB‐334867 reduces responding to a natural reinforcer in food‐restricted and food‐sated rats. Additionally, these studies used microdialysis and in vivo voltammetry in rats to examine whether SB‐334867 attenuates the effects of cocaine on dopamine signaling within the nucleus accumbens core. Furthermore, in vitro voltammetry was used to examine whether hypocretin knockout mice display attenuated dopamine responses to cocaine. Results indicate that when SB‐334867 was administered peripherally or within the ventral tegmental area, it reduced the motivation to self‐administer cocaine and attenuated cocaine‐induced enhancement of dopamine signaling. SB‐334867 also reduced the motivation to self‐administer sucrose in food‐sated but not food‐restricted rats. Finally, hypocretin knockout mice displayed altered baseline dopamine signaling and reduced dopamine responses to cocaine. Combined, these studies suggest that hypocretin neurotransmission participates in reinforcement processes, likely through modulation of the mesolimbic dopamine system. Additionally, the current observations suggest that the hypocretin system may provide a target for pharmacotherapies to treat cocaine addiction. 相似文献
122.
Because breast tissue composition partially predicts breast cancer risk, classification of mammography reports by breast tissue composition is important from both a scientific and clinical perspective. A method is presented for using the unstructured text of mammography reports to classify them into BI-RADS breast tissue composition categories. An algorithm that uses regular expressions to automatically determine BI-RADS breast tissue composition classes for unstructured mammography reports was developed. The algorithm assigns each report to a single BI-RADS composition class: 'fatty', 'fibroglandular', 'heterogeneously dense', 'dense', or 'unspecified'. We evaluated its performance on mammography reports from two different institutions. The method achieves >99% classification accuracy on a test set of reports from the Marshfield Clinic (Wisconsin) and Stanford University. Since large-scale studies of breast cancer rely heavily on breast tissue composition information, this method could facilitate this research by helping mine large datasets to correlate breast composition with other covariates. 相似文献
123.
124.
125.
Wang L Lawrence MS Wan Y Stojanov P Sougnez C Stevenson K Werner L Sivachenko A DeLuca DS Zhang L Zhang W Vartanov AR Fernandes SM Goldstein NR Folco EG Cibulskis K Tesar B Sievers QL Shefler E Gabriel S Hacohen N Reed R Meyerson M Golub TR Lander ES Neuberg D Brown JR Getz G Wu CJ 《The New England journal of medicine》2011,365(26):2497-2506
126.
Chimowitz MI Lynn MJ Derdeyn CP Turan TN Fiorella D Lane BF Janis LS Lutsep HL Barnwell SL Waters MF Hoh BL Hourihane JM Levy EI Alexandrov AV Harrigan MR Chiu D Klucznik RP Clark JM McDougall CG Johnson MD Pride GL Torbey MT Zaidat OO Rumboldt Z Cloft HJ;SAMMPRIS Trial Investigators 《The New England journal of medicine》2011,365(11):993-1003
127.
Peter J. Lang Bethany C. Wangelin Margaret M. Bradley Francesco Versace Paul W. Davenport Vincent D. Costa 《Psychophysiology》2011,48(3):393-396
The current study examined emotional reflex reactions of participants threatened with respiratory distress caused by imposing a resistive load at inspiration. Cues signaling threat (breathing MAY be difficult) and safe periods were intermixed while startle reflexes, heart rate, skin conductance, and facial EMG activity were measured. Compared to safe cues, threat cues elicited significant startle potentiation, enhanced skin conductance, heightened corrugator EMG changes, and pronounced “fear bradycardia” consistent with defensive activation in the context of threatened respiratory dysfunction. These data indicate that anticipating respiratory resistance activates defensive responding, which may mediate symptomatology in patients with panic and other anxiety disorders. 相似文献
128.
129.
This study examined the barriers and facilitators of HIV counseling, testing, and referral service (HIV CTR) acceptance among 278 youth aged 12-24 years old. Participants completed a questionnaire before health education sessions with trained counselors. Information was collected on individual characteristics, HIV testing acceptance, risk behaviors, reasons for having never been tested, and what would make it easier to get tested for HIV. Ninety percent of the respondents were minority and 52% were female with an average age of 15 years. High-risk minority youth who had never received HIV CTR listed low perception of risk and never having been offered a test as reasons for not having been tested. Increased availability of oral and rapid testing methods as well as free testing services were listed as facilitating their acceptance of HIV testing. Older youth aged 18-24 years reported that HIV tests in which results can be received rapidly and confidentially would encourage them to obtain HIV testing services. Early identification approaches should be tailored to increase the access to and acceptance of HIV-testing services among the adolescent and young adult populations. 相似文献
130.