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   13982篇
  免费   813篇
  国内免费   54篇
耳鼻咽喉   106篇
儿科学   340篇
妇产科学   276篇
基础医学   1924篇
口腔科学   555篇
临床医学   1828篇
内科学   2668篇
皮肤病学   149篇
神经病学   1426篇
特种医学   416篇
外科学   1972篇
综合类   68篇
一般理论   9篇
预防医学   1039篇
眼科学   201篇
药学   1010篇
中国医学   9篇
肿瘤学   853篇
  2023年   114篇
  2022年   113篇
  2021年   262篇
  2020年   223篇
  2019年   265篇
  2018年   360篇
  2017年   294篇
  2016年   391篇
  2015年   383篇
  2014年   497篇
  2013年   794篇
  2012年   868篇
  2011年   929篇
  2010年   684篇
  2009年   689篇
  2008年   845篇
  2007年   860篇
  2006年   839篇
  2005年   820篇
  2004年   749篇
  2003年   668篇
  2002年   649篇
  2001年   135篇
  2000年   109篇
  1999年   145篇
  1998年   145篇
  1997年   114篇
  1996年   97篇
  1995年   74篇
  1994年   96篇
  1993年   79篇
  1992年   86篇
  1991年   77篇
  1990年   50篇
  1989年   60篇
  1988年   68篇
  1987年   67篇
  1986年   70篇
  1985年   73篇
  1984年   78篇
  1983年   66篇
  1982年   69篇
  1981年   52篇
  1980年   53篇
  1979年   56篇
  1978年   56篇
  1977年   49篇
  1976年   44篇
  1975年   44篇
  1954年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Summary Eighteen patients with advanced solid cancer were treated with daily 5-dFUrd infusions given over 1 h on days 1–5 of a 4-week cycle. Nine patients received 3 g/m2 5-dFUrd daily and another nine patients 5 g/m2. One patient on 5 g/m2 5-dFUrd was not fully evaluable for tolerability due to early death (progressive disease) 4 weeks after the first cycle. A total of 48 cycles was given. The gastrointestinal and hematological toxicity was generally mild (grade 1–2). Central neurotoxicity (ataxia, unsteadiness, diplopia, dysarthria, sometimes confusion) was observed in 7 of 8 patients on 5 g/m2 5-dFUrd leading to premature discontinuation of treatment in 3 patients (after 2 cycles). Only 3 of the 9 patients in the 3 g/m2 group had slight signs of cerebellopathy. Typically, the reversible neurological side effects started at the end of the 2nd week of a cycle. The serum elimination kinetics of 5-dEUrd and its metabolites 5-FU and 5-dFUH2 have been investigated in the serum and showed very low intra- and interindividual variations. Peak concentrations of the 5-dFUrd at the end of the infusion approximated 500 mol/l and 1000 mol/l for the 3 g/m2 and 5 g/m2 group, respectively. The peak of the serum 5-FU was reached at the same time, the ratio 5-FU/5-dFUrd being around 10%. The elimination half-life time for 5-FU was protracted by a factor of 2–3 compared with the direct injection of 5-FU.Monthly infusion of 5-dFUrd 5 mg/m2 per day on days 1–5 lead to an unacceptable frequency and degree of neurological toxicity. Similar infusions of 5-dFUrd 3 g/m2 per day on days 1–5 were well tolerated.  相似文献   
112.
The effects in rats of long-term administration of the potent, specific 5-HT uptake inhibitor citalopram have been investigated. Citalopram hydrobromide (MW=405) was given in the diet, 99 or 25 mol/kg daily, for 13 days or orally, 49 mol/kg twice a day, for 14 days. High plasma and brain levels of citalopram were found during the treatment period, whereas negligible amounts were found 24 h after withdrawal. The 5-HT uptake mechanism in blood platelets was completely blocked, since levels of whole blood 5-HT during and shortly (2 days) after treatment were decreased by 75–90%. The drug load after the two highest doses in terms of plasma drug levels was the same as in depressed patients treated with citalopram. Receptor binding technique ex vivo was applied to different brain parts to measure receptor parameters for several neurotransmitters. All data were evaluated by Eadie-Hoffstee analysis. No changes were seen in B max and K d for -receptors (3H-dihydroalprenolol) in frontal cortex, occipital+temporal cortex, whole cortex and limbic structures, 5-HT2 receptors (3H-spiroperidol) in frontal and whole cortex, 1-receptors (3H-prazosin) in rest of brain and DA D-2 receptors (3H-spiroperidol) in corpus striatum and limbic structures. The uptake mechanism for 5-HT as well as the inhibitory effect of citalopram on this uptake remained unaffected in brain synaptosomes derived from control and from citalopram (99 mol/kg)-treated rats. Thus long-term treatment with citalopram does not induce changes in neurotransmitter receptors as seen with most tricyclic as well as newer atypical antidepressants. Most striking is the lack of - and 5-HT2 receptor down-regulation. Since citalopram clinically shows clear antidepressant activity, this down-regulation does not seem to be a prerequisite of antidepressant activity.  相似文献   
113.
The effect of prolonged administration of the potent and specific 5-HT uptake inhibitor citalopram on behavioural measures of dopaminergic and serotonergic activity has been studied in rats. Administration of citalopram in the diet at a daily dose of 99 mol/kg led to supersensitivity to d-amphetamine-induced hypermotility and stereotypy and to subsensitivity to apomorphine-induced hypomotility 2 h after withdrawal. Forepaw clonus induced by 5-methoxy-N,N-dimethyltryptamine was decreased 2 h and 24 h after withdrawal and the number of head shakes induced by 1-5-HTP and citalopram were decreased 24 h after withdrawal. The d-amphetamine potentiation was still seen after 24 h, whereas the response had returned to normal 3 and 7 days after withdrawal. The content of amphetamine in three different brain regions was about 50% higher compared with controls 24 h after withdrawal of prolonged citalopram administration. At this time citalopram had been eliminated, and citalopram itself could not affect amphetamine metabolism. Other experiments indicated a linear relation between d-amphetamine brain concentration and motility level. Thus, a 50% increase in citalopram-treated rats cannot alone account for 3-fold increase in d-amphetamine-induced motility. Potentiation of d-amphetamine-induced hypermotility was also found after citalopram in a daily dietary dose of 25 mol/kg for 13 days and after oral bolus injection (49 mol/kg twice daily for 14 days). Acute citalopram injection had no effect in any of these models. The results suggest increased responsiveness of dopaminergic mechanisms mediating hypermotility, and decreased sensitivity of dopamine receptors mediating sedation (proposed autoreceptors). Sensitivity of 5-HT receptors was also decreased. The mechanisms by which citalopram induces d-amphetamine supersensitivity as well as subsensitivity to apomorphine and 5-HT agonists are presently unknown, since no changes in dopaminergic and serotonergic receptor binding have been found after an identical dose regimen.  相似文献   
114.
For a drug with concentration-dependent serum protein binding, the unbound fraction of drug decreases during the drug elimination process. The clearance of the drug at a given blood flow rate is lower than would be expected from the observed unbound fraction in venous blood from a noneliminating organ. Based on both the well-stirred and parallel tube models, simulations demonstrated that consideration of concentration-dependent binding during drug elimination is important when the intrinsic clearance is higher than the blood flow and when the unbound drug concentration is much greater than the dissociation equilibrium constant of the binding complex.Supported in part by Grant GM 28423 from the National Institutes of General Medical Sciences, NIH.  相似文献   
115.
Quality of Life Research - We examined multidimensional, heterogeneous reactions to the COVID-19 pandemic and associated measures to provide further insights into the developmental processes of...  相似文献   
116.
Aim

The immigrant population continues to increase in Norway, and Somali immigrants and their descendants are presently the largest non-Western group. We have limited knowledge about the health status in this population. The aim of this study was to assess self-perceived health status among Somalis in Norway.

Method

We used data from a study assessing risk factors for lifestyle diseases among Somali immigrants in Oslo, which was conducted between December 2015 and October 2016, among men and women aged 20–73 who were living in the Sagene borough in Oslo.

Results

The study population included 221 participants (112 females and 110 males). Overall, 78% of the participants (70% of females and 86% males) rated their health status as good or very good. Women had poorer self-reported health (p?=?0.003) than men. Being unemployed and having diabetes, stress, and sleeping problems were associated with poor self-reported health, but time lived in Norway, education level, Norwegian language proficiency, and high BMI were not significantly associated. Around 2/3 of the participants reported being physically inactive, while around half reported walking or moving more than 30 min per day. Self-reported chronic diseases such as diabetes and hypertension were 5% and 9% respectively.

Conclusion

This study has shown the different patterns of self-reported health status among Somali immigrants in Norway, as associated with gender, age, psychosocial conditions, and employment status. Further research is needed to explain why Somali women in Norway have poorer self-reported health than men. The findings from this study should provide direction to healthcare providers for improving health among immigrants, for example through implementing a community-driven and culturally appropriate lifestyle intervention program.

  相似文献   
117.
Current treatment recommendations for non-alcoholic fatty liver disease (NAFLD) rely heavily on lifestyle interventions. The Mediterranean diet and physical activity, aiming at weight loss, have shown good results in achieving an improvement of this liver disease. However, concerns related to compliance and food accessibility limit the feasibility of this approach, and data on the long-term effects on liver-related outcomes are lacking. Insulin resistance is a central aspect in the pathophysiology of NAFLD; therefore, interventions aiming at the improvement of insulin sensitivity may be preferable. In this literature review, we provide a comprehensive summary of the available evidence on nutritional approaches in the management of NAFLD, involving low-calorie diets, isocaloric diets, and the novel schemes of intermittent fasting. In addition, we explore the harmful role of single nutrients on liver-specific key metabolic pathways, the role of gene susceptibility and microbiota, and behavioral aspects that may impact liver disease and are often underreported in clinical setting. At present, the high variability in terms of study populations and liver-specific outcomes within nutritional studies limits the generalizability of the results and highlights the urgent need of a tailored and standardized approach, as seen in regulatory trials in Non-Alcoholic Steatohepatitis (NASH).  相似文献   
118.
Prevention Science - The effectiveness of bullying prevention programs has led to expectations that these programs could have effects beyond their primary goals. By reducing the number of victims...  相似文献   
119.
Journal of Occupational Rehabilitation - Purpose There is a lack of results on long-term effects of return to work interventions. We previously reported that an inpatient multimodal occupational...  相似文献   
120.
Allogeneic islet transplantation in type 1 diabetes requires lifelong immunosuppression to prevent graft rejection. This medication can cause adverse effects and increases the susceptibility for infections and malignancies. Adoptive therapies with regulatory T cells (Tregs) have shown promise in reducing the need for immunosuppression in human transplantation settings but have previously not been evaluated in islet transplantation. In this study, five patients with type 1 diabetes undergoing intraportal allogeneic islet transplantation were co-infused with polyclonal autologous Tregs under a standard immunosuppressive regimen. Patients underwent leaukapheresis from which Tregs were purified by magnetic-activated cell sorting (MACS) and cryopreserved until transplantation. Dose ranges of 0.14–1.27 × 106 T cells per kilo bodyweight were transplanted. No negative effects were seen related to the Treg infusion, regardless of cell dose. Only minor complications related to the immunosuppressive drugs were reported. This first-in-man study of autologous Treg infusion in allogenic pancreatic islet transplantation shows that the treatment is safe and feasible. Based on these results, future efficacy studies will be developed under the label of advanced therapeutic medical products (ATMP), using modified or expanded Tregs with the aim of minimizing the need for chronic immunosuppressive medication in islet transplantation.  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