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   1390篇
  免费   90篇
  国内免费   8篇
耳鼻咽喉   7篇
儿科学   40篇
妇产科学   25篇
基础医学   173篇
口腔科学   38篇
临床医学   112篇
内科学   308篇
皮肤病学   18篇
神经病学   147篇
特种医学   39篇
外科学   248篇
综合类   8篇
一般理论   2篇
预防医学   110篇
眼科学   27篇
药学   97篇
中国医学   6篇
肿瘤学   83篇
  2023年   3篇
  2022年   4篇
  2021年   41篇
  2020年   27篇
  2019年   35篇
  2018年   48篇
  2017年   24篇
  2016年   34篇
  2015年   36篇
  2014年   60篇
  2013年   65篇
  2012年   106篇
  2011年   82篇
  2010年   75篇
  2009年   52篇
  2008年   118篇
  2007年   97篇
  2006年   86篇
  2005年   76篇
  2004年   66篇
  2003年   64篇
  2002年   82篇
  2001年   19篇
  2000年   23篇
  1999年   18篇
  1998年   11篇
  1997年   15篇
  1996年   16篇
  1995年   6篇
  1994年   5篇
  1993年   3篇
  1992年   9篇
  1991年   15篇
  1990年   11篇
  1989年   10篇
  1988年   3篇
  1986年   2篇
  1985年   3篇
  1983年   3篇
  1982年   4篇
  1981年   2篇
  1980年   2篇
  1979年   4篇
  1978年   5篇
  1977年   3篇
  1975年   3篇
  1974年   2篇
  1971年   2篇
  1970年   3篇
  1967年   1篇
排序方式: 共有1488条查询结果,搜索用时 15 毫秒
1.
Data about treatment outcomes and toxicity in Latin America are scarce. There are differences with central countries based on access to healthcare system and socioeconomic status. Argentinean Society of Hematology recommends bortezomib-based triplets for induction treatment of transplant eligible newly diagnosed multiple myeloma patients. Most common options are CyBorD (cyclophosphamide, bortezomib and dexamethasone) and VTD (bortezomib, thalidomide and dexamethasone). Main goal of our retrospective, multicentric study was to compare very good partial response rate (VGPR) or better after induction treatment in a real-world setting in Argentina. Secondary objectives included comparison of complete response (CR) post-induction and after bone marrow transplantation, grade 3-4 adverse events (AEs), progression-free survival (PFS) and overall survival (OS). Three hundred twenty-two patients were included (median age at diagnosis: 57 years; 52% male; 28% had ISS3; 14% with high-risk cytogenetics; median follow up: 34 months). CyBorD was indicated in 74% and 26% received VTD. In VTD arm, 72.62% of patients achieved at least VGPR vs 53.36% receiving CyBorD (odds ratio, OR: 1.96 [95% confidence interval, CI: 1.08-3.57; P = .026] after adjusting by age, ISS [International Staging System], lactate dehydrogenase levels (LDH) and cytogenetic risk. Difference in VGPR was 19.26% (95% CI: 15-24). CR rate were 35.92% (VTD) vs 22.55% (CyBorD) (adjusted OR: 2.13 [95% CI: 1.12-4.05]). Difference in CR was 13.37% (95% CI: 9.6-17.53). Adverse events (AEs) were more common with VTD (69.05% vs 55.46% for CyBorD; P = .030), especially grade 3-4 neuropathy (P = .005) and thrombosis (P = .001). Thromboprophylaxis was inadequate in 20.24% of patients. Hematological AEs were more common with CyBorD, especially thrombocytopenia (P = .017). PFS and OS at 24 months were not different between treatments. In this real-world setting, VTD was associated with better CR and VGPR than CyBorD. Nevertheless, CyBorD continues to be the preferred induction regimen in Argentina, based on safety profile. Frontline autologous stem cell transplantation improves quality of responses, especially in countries with limited access to new drugs.  相似文献   
2.
Recent reports have shown that the avian visual dorsal ventricular ridge (DVR) is organized as a trilayered complex, in which the forming layers—the thalamo-recipient entopallium (E), an overlaying nidopallial stripe called intermediate nidopallium (NI), and the dorsally adjacent mesopallium ventrale—appear to be extensively interconnected by topographically organized columns of reciprocal axonal processes running perpendicular to the layers, an arrangement highly reminiscent to that of the sensory cortices of mammals. In the present report, we implemented in vivo anterograde and retrograde tracing techniques aiming to elucidate the organization of the connections of this complex with other pallial areas. Previous studies have shown that the efferent projections of the visual DVR originate mainly from the NI and E, reaching several distinct associative and premotor nidopallial areas. We found that the efferents from the visual DVR originated solely from the NI, and confirmed that the targets of these projections were the pallial areas described by previous studies. We also found novel projections from the NI to the visual hyperpallium, and to the lateral striatum. Moreover, we found that these projections were reciprocal, topographically organized, and originated from different cell populations within the NI. We conclude that the NI constitutes a specialized layer of the visual DVR that form the core of a dense network of highly specific connections between this region and other higher order areas of the avian pallium. Finally, we discuss to what extent these hodological properties resemble those of the mammalian cortical layers II/III.  相似文献   
3.
Electroencephalogram (EEG) stands out as a highly translational tool for psychiatric research, yet rodent and human EEG are not typically obtained in the same way. In this study we developed a tool to record skull EEG in awake-behaving rats in a similar manner to how human EEG are obtained and then used this technique to test whether acute NMDA receptor antagonism alters rodent EEG signals in a similar manner as in humans. Acute MK-801 treatment elevated gamma power and reduced beta band power, which closely mirrored EEG data from healthy volunteers receiving acute ketamine. To explore the mechanisms behind these oscillatory changes, we examined the effects of GABA-A receptor blockade, finding that picrotoxin (PTX) recapitulated the decrease in sound-evoked beta oscillations observed with acute MK-801, but did not produce changes in gamma band power. Chronic treatment with either PTX or MK-801 did not affect frequency-specific oscillatory activity when tested 24 h after the last drug injection, but decreased total broadband oscillatory power. Overall, this study validated a novel platform for recording rodent EEG and demonstrated similar oscillatory changes after acute NMDA receptor antagonism in both humans and rodents, suggesting that skull EEG may be a powerful tool for further translational studies.  相似文献   
4.
In Pavlovian conditioning, sign- and goal-tracking behaviors represent different approaches towards the conditioned stimulus. These behavioral patterns have been associated with predictive or incentive properties of the conditioned stimulus, with a crucial involvement of the mesolimbic dopamine system. As it is possible that sign tracking behavior is more sensitive to dopamine modulation, we evaluated the dopamine-dependence of sign- and goal-tracking behavior. We assessed responses to both a D2 agonist and an antagonist, and tested performance in a behavioral paradigm known to activate dopamine projections and in an animal model that affects mesolimbic and mesocortical function. Sign trackers displayed a greater sensitivity to a D2 agonist and smaller prepulse inhibition of the acoustic startle response than goal trackers, suggesting a reduced inhibitory ability. In addition, a neonatal ventral hippocampal lesion resulted in the loss of incentive salience of cues in sign trackers. Overall, these data indicate that sign-tracking behavior is more heavily controlled by dopamine than goal tracking.  相似文献   
5.
6.
Early this year, a Massachusetts Institute of Technology professor of philosophy presented a new theory of time that caught our interest. One of the key concepts that Professor Skow presented is the “moving spotlight” theory. As Skow asserts, the experiences had a year ago or 10 years ago are still just as real, they’re just “inaccessible” because they are now in a different part of spacetime. This was felt to be an elegant notion to inform this ‘spotlight’ piece on BEME (www.bemecollaboration.org).  相似文献   
7.
The purpose of this study was to evaluate the area under the concentration-time curve (AUC) ratio as an optimal indicator of the pharmacokinetic advantage during hyperthermic intraperitoneal perioperative chemotherapy. The impact on the AUC ratio on the variables related to the calculation of systemic drug exposure, instillation time, and peripheral drug distribution was evaluated through simulations as well as through a retrospective analysis of studies published in the literature. Both model simulations and the retrospective analysis showed that the 3 variables evaluated had an impact on the AUC ratio value if the complete systemic exposure was not fully considered. However, when that complete systemic exposure was considered, none of these variables affected the AUC ratio value. AUC ratio is not a characteristic parameter of a drug if the calculated systemic drug exposure is not complete. Thus, AUC ratio is not valid for comparing the pharmacokinetic advantage of 2 drugs, and it should not be employed to prove whether a drug can be used in hyperthermic intraperitoneal perioperative chemotherapy safely with regard to toxicity. As an alternative, the study of the absorption rate constant and the bioavailability are proposed as the true and independent parameters that reflect the amount of drug absorbed.  相似文献   
8.
9.
This article analyzes issues related to U.S. hired farmworkers’ utilization of health care services and their specific choices among health care provider and health bill payment method options. Using data from the National Agricultural Workers Surveys for the years 2000–2012, this article employs propensity score matching and probit estimation techniques to examine the health care utilization of hired farmworkers. This study’s results indicate that undocumented hired farmworkers are 10.7 and 3% less likely to use U.S. and foreign health care, respectively, compared to documented farmworkers. Health insurance is found to significantly increase hired farmworkers’ use of U.S. health care by 22.3%. Notably, compared to their documented working peers, undocumented workers are much less likely to patronize private clinics. They are even less likely to rely on migrant health centers even when these providers are their most viable sources of health care service.  相似文献   
10.
This clinical trial sought to evaluate the effectiveness of alternative treatment for replacing amalgam and resin-based composite restorations with marginal defects. The study recruited 66 patients with 271 restorations. Each restoration was assigned randomly to one of five groups: Sealant, Refurbishing, Repair, Replacement, and Untreated. Two clinicians evaluated the restorations according to USPHS/Ryge criteria at baseline (Kappa 0.74) and one year after the treatment (Kappa 0.81). The scoring of the margins improved (from bravo to alfa) after the experimental treatments. None of the treatments showed significant degradation of the margins during the 12-month observation period.  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