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   2214篇
  免费   86篇
  国内免费   7篇
耳鼻咽喉   35篇
儿科学   96篇
妇产科学   15篇
基础医学   189篇
口腔科学   35篇
临床医学   144篇
内科学   460篇
皮肤病学   38篇
神经病学   119篇
特种医学   72篇
外科学   496篇
综合类   59篇
预防医学   110篇
眼科学   154篇
药学   127篇
中国医学   6篇
肿瘤学   152篇
  2023年   11篇
  2022年   29篇
  2021年   102篇
  2020年   48篇
  2019年   68篇
  2018年   80篇
  2017年   57篇
  2016年   72篇
  2015年   70篇
  2014年   107篇
  2013年   126篇
  2012年   214篇
  2011年   194篇
  2010年   122篇
  2009年   102篇
  2008年   167篇
  2007年   143篇
  2006年   123篇
  2005年   103篇
  2004年   86篇
  2003年   78篇
  2002年   87篇
  2001年   14篇
  2000年   11篇
  1999年   25篇
  1998年   5篇
  1997年   6篇
  1996年   7篇
  1995年   9篇
  1994年   5篇
  1993年   2篇
  1992年   5篇
  1991年   6篇
  1990年   6篇
  1989年   4篇
  1988年   3篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1979年   1篇
  1974年   1篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
排序方式: 共有2307条查询结果,搜索用时 15 毫秒
1.
2.
3.
Aim: This article reviews research centred around juvenile bipolar disorder with particular reference to diagnostic difficulties. Putative deficits are scrutinized with respect to trait likelihood and the roles of neuropsychology and neuroimaging in enhancing our understanding of juvenile bipolar disorder are discussed. Methods: Search terms including childhood, adolescent, youth and juvenile combined with the terms ‘bipolar disorder’, mania, depression and hypomania were used to identify relevant studies in MEDLINE and PsychLit. Results: Over recent years research into this relatively new disorder has increased phenomenally. Key issues within the field include diagnostic specificity, the heritability of the disorder, the impact of comorbidity and the implications of neuropsychological and neuroimaging findings. Conclusion: Despite concerning controversies in literature the diagnosis of bipolar disorder in children and adolescents as compared with adults, promising future research directions include better neurological characterization of the disorder through the application of findings from clinical populations, neuropsychological and neuroimaging research.  相似文献   
4.
OBJECTIVE: Recent studies of patients with juvenile bipolar disorder report low rates of recovery and high rates of chronicity. However, we lack data on the short-term outcome. This study examines the pattern of recovery from the index episode in an aggressively treated juvenile sample. METHOD: We assessed 25 subjects (< 16 years) with a diagnosis of mania, using the Diagnostic Interview for Children and Adolescents-Revised) (DICA-R), Young Mania Rating Scale (YMRS), and Children's Global Assessment Scale (CGAS) at intake and at 3 and 6 months. We studied the time taken to recover from the index episode, the level of functioning, and the factors predicting them. RESULTS: After 6 months, 24 (96%) subjects had recovered from the index manic episode. The median time to recovery was 27 days. Total episode length was significantly longer among those with previous affective episodes. CONCLUSIONS: The findings suggest that juvenile-onset mania has high rates of recovery and low rates of chronicity. These differences from the existing literature need further exploration.  相似文献   
5.
This paper examines the role of selective serotonin reuptake inhibitors (SSRIs) in the treatment of hepatitis-C virus (HCV) patients who have developed interferon-α induced depression. A 2-year data analysis of HCV psychiatric liaison clinic has been undertaken. The diagnosis, treatment, and progress of those patients who were treated with interferon-α (INF-α) are reported. 53 of the 78 patients enrolled at the HCV Clinic and treated with INF-α were referred for psychiatric consultation. Six patients developed major depressive illness following INF therapy. They were all treated with SSRIs and they made full recovery. This is a significant observation and is concordant with other studies. Its biochemical ramifications are presented. It is concluded that INF-induced depression is fully reversible. A hypothesis is proposed that SSRIs modulate the neuro-protective neurotoxic ratio by possibly inhibiting the indole-2,3-dioxygenase induction of the kynurenine pathway.  相似文献   
6.
Tissue ischemia, necrosis, and gangrene are uncommon but well-described complications of arterial catheterization in the neonate. Treatment options for progressive tissue necrosis following arterial embolization and/or vasospasm are limited in these patients secondary to unpredictable pharmacokinetics and risks associated with systemic anticoagulation or vasodilatation in newborns. We report a case of a multidose regimen of topical 2% nitroglycerin ointment for reversing severe tissue ischemia following peripheral arterial line placement. The favorable response in this infant suggests that topical nitroglycerin therapy should be considered as potential therapy to ameliorate the effects of vascular compromise following arterial line placement in neonates.  相似文献   
7.
The reaction of poly(styryl)lithium (PSLi) with hexa‐1,3,5‐triene (HXT) was studied as a route to diene‐functionalized macromonomers. When PSLi was reacted with 1.5 molar equivalents of HXT for 2.5 h at ?10 °C in toluene, it was found that the diene‐functionalized macromonomer was obtained in high yield; however, oligomerization of the HXT was observed by matrix‐assisted laser absorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Oligomerization was eliminated by running the reaction with only 1.2 molar equivalents of HXT to PSLi and allowing the reaction to run for 15 min at ?10 °C in toluene. The resulting polymer exhibited high diene chain‐end functionality and no oligomerization was observed by MALDI‐TOF MS. 13C NMR spectroscopy and the attached‐proton test (APT), along with calculated chemical shifts, showed the presence of both the 1,2‐ and 1,4‐addition chain‐end structures. Further analysis by the reaction of the functional polymer with maleic anhydride indicated that 18 wt.‐% of the product was unreactive, either because of a 1,4‐addition chain‐end structure or a nonfunctional polymer. The structure of the maleic anhydride‐modified polymer was determined by MALDI‐TOF MS and 13C NMR spectroscopy. Preliminary work on the reactivity of the diene‐functionalized macromonomers was performed by the addition of a large excess of PSLi to a solution of macromonomer followed by characterization by size‐exclusion chromatography (SEC).

The formation of hexa‐1,3,5‐triene‐functionalized polystyrenes and their reaction with maleic anhydride.  相似文献   

8.
We describe non‐radiative energy‐transfer experiments to measure the rates of polymer interdiffusion in P(MMA‐co‐BA) latex films formed in the presence of poly(vinyl alcohol) (PVOH). PVOH had relatively little effect on the initial efficiency of energy transfer, even when the amount of PVOH was large enough to form the continuous phase. Since ΦET(0) is a measure of the interfacial area between D‐ and A‐labeled cells in the film, we conclude that under these circumstances the dispersed P(MMA‐co‐BA) copolymer is in the form of clusters with many contacts between particles containing D and A labels. These large amounts of PVOH also reduce the amount of polymer diffusion that takes place when the films are annealed. When smaller amounts of PVOH are present, the effects are measurable but much smaller. In the presence of 2 to 17 wt.‐% PVOH, the polymer diffusion rate is retarded. The magnitude of the effect increases with the amount of PVOH present, and the effect is larger at 45 °C than at 63 °C. We show that the PVOH has its largest influence at the very early stages of polymer diffusion.

Schematic representation of an energy transfer experiment, which monitors polymer interdiffusion in a latex film.  相似文献   

9.
Methimazole (methyl-mercapto-imidazole, MMI), a compound used clinically in therapy of Graves' thyroiditis, was found to inhibit development of several autoimmune diseases in animal models. It was suggested on the basis of in vitro data that inhibition is through down-regulation of interferon-gamma (IFN-gamma)-induced expression of major histocompatibility complex class I and class II molecules. Here, we investigate the effect of MMI on experimental autoimmune uveoretinitis (EAU) and study its mechanism(s). Treatment of EAU with MMI administered in drinking water inhibited induction of the disease and associated antigen (Ag)-specific proliferation and cytokine production by draining lymph node cells (LNCs). The treatment was protective only if administered during the first but not during the second week after immunization, suggesting an effect on the induction phase of EAU. It is interesting that MMI inhibited disease in IFN-gamma knockout mice, indicating that the in vivo protective effect is IFN-gamma-independent. Flow cytometric analysis of draining LNCs extracted 5 days after immunization showed that MMI partly to completely reversed the increase in Mac-1(+)/class I(+)/class II(+) cells induced by immunization and reduced the proportion of B7-1 and CD40-positive cells, suggesting a deficit in the Ag-presenting cell (APC) population. APC from untreated mice largely restored antigen-specific proliferation of MMI-treated LNCs. We suggest that MMI inhibits EAU at least in part by preventing the recruitment and/or maturation of APC, resulting in reduced generation of Ag-specific T cells.  相似文献   
10.
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