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   1782篇
  免费   227篇
耳鼻咽喉   11篇
儿科学   108篇
妇产科学   37篇
基础医学   246篇
口腔科学   71篇
临床医学   278篇
内科学   273篇
皮肤病学   19篇
神经病学   165篇
特种医学   53篇
外科学   309篇
综合类   13篇
预防医学   168篇
眼科学   16篇
药学   152篇
中国医学   1篇
肿瘤学   89篇
  2023年   27篇
  2022年   12篇
  2021年   30篇
  2020年   43篇
  2019年   49篇
  2018年   102篇
  2017年   102篇
  2016年   72篇
  2015年   77篇
  2014年   102篇
  2013年   228篇
  2012年   136篇
  2011年   148篇
  2010年   115篇
  2009年   54篇
  2008年   38篇
  2007年   17篇
  2006年   27篇
  2005年   23篇
  2004年   10篇
  2003年   11篇
  2002年   7篇
  2001年   19篇
  2000年   25篇
  1999年   17篇
  1998年   27篇
  1997年   32篇
  1996年   24篇
  1995年   27篇
  1994年   21篇
  1993年   16篇
  1992年   32篇
  1991年   20篇
  1990年   14篇
  1989年   18篇
  1988年   26篇
  1987年   15篇
  1986年   9篇
  1985年   13篇
  1984年   25篇
  1983年   17篇
  1982年   24篇
  1981年   22篇
  1980年   22篇
  1979年   9篇
  1978年   8篇
  1976年   11篇
  1975年   9篇
  1974年   10篇
  1973年   7篇
排序方式: 共有2009条查询结果,搜索用时 15 毫秒
41.
42.
43.
Appropriate feeding behaviours are important for child growth and development. In societies undergoing nutrition transition, new food items are introduced that may be unfavourable for child health. Set in rural Nicaragua, the aim of this study was to describe the infant and young child feeding (IYCF) practices as well as the consumption of highly processed snack foods (HP snacks) and sugar‐sweetened beverages (SSBs). All households with at least one child 0‐ to 35‐month‐old (n = 1371) were visited to collect information on current IYCF practices in the youngest child as well as consumption of SSBs and HP snacks. Breastfeeding was dominant (98%) among 0‐ to 1‐month‐olds and continued to be prevalent (60%) in the second year, while only 34% of the 0‐ to 5‐month‐olds were exclusively breastfed. Complementary feeding practices were deemed acceptable for only 59% of the 6‐ to 11‐month‐old infants, with low dietary diversity reported for 50% and inadequate meal frequency reported for 30%. Consumption of HP snacks and SSBs was frequent and started early; among 6‐ to 8‐month‐olds, 42% and 32% had consumed HP snacks and SSBs, respectively. The difference between the observed IYCF behaviours and World Health Organization recommendations raises concern of increased risk of infections and insufficient intake of micronutrients that may impair linear growth. The concurrent high consumption of SSBs and HP snacks may increase the risk of displacing the recommended feeding behaviours. To promote immediate and long‐term health, growth and development, there is a need to both promote recommended IYCF practices as well as discourage unfavourable feeding behaviours.  相似文献   
44.
45.
46.
Obstructive sleep apnoea and residual neuromuscular blockade are, independently, known to be risk factors for respiratory complications after major surgery. Residual effects of neuromuscular blocking agents are known to reduce the hypoxic ventilatory response in healthy volunteers. Patients with obstructive sleep apnoea have impaired control of breathing, but it is not known to what extent neuromuscular blocking agents interfere with the regulation of breathing in such patients. In a physiological study in 10 unsedated men with untreated obstructive sleep apnoea, we wished to examine if partial neuromuscular blockade had an effect on hypoxic ventilatory response (isocapnic hypoxia to oxygen saturation of 80%) and hypercapnic ventilatory response (normoxic inspired carbon dioxide 5%). The hypoxic ventilatory response was reduced by 32% (p = 0.016) during residual neuromuscular block (rocuronium to train-of-four ratio 0.7), but the hypercapnic ventilatory response was unaffected. We conclude that neuromuscular blockade specifically depresses peripheral chemosensitivity, and not respiratory muscle function since the hypercapnic ventilatory response was unaffected.  相似文献   
47.

Background

Breast magnetic resonance imaging (MRI) has shown high sensitivity in determining tumor extent, multifocality, and occult contralateral breast cancer. Low specificity, unnecessary mastectomies, and costs are arguments against MRI. The purpose of this study was to determine whether preoperative breast MRI would affect primary surgical management, reduce reexcision/reoperation procedures, and influence the choice of neoadjuvant treatment in patients with newly diagnosed breast cancer.

Methods

This prospective, randomized, multicenter study included 440 breast cancer patients younger than aged 56 years from three, Swedish, large-volume breast units. Patients were randomly allocated on a 1:1 basis to either preoperative staging with breast MRI (n = 220) or no breast MRI (n = 220) (control group). Treatment planning of all patients was discussed at multidisciplinary team conferences.

Results

In patients randomized to the MRI group, who had an observed higher percentage of planned breast-conserving surgery (BCS) compared with the control group, a change from suggested breast conservation to mastectomy occurred in 23 of 153 (15 %) patients. Breast MRI provided additional information in 83 of 220 (38 %) patients, which caused a change in treatment plan in 40 (18 %). The breast reoperation rate was significantly lower in the MRI group: 11 of 220 (5 %) versus 33 of 220 (15 %) in the control group (p < 0.001). The number of mastectomies, axillary reoperations, and the number of patients receiving neoadjuvant chemotherapy after definitive treatment did not differ significantly between the groups.

Conclusions

Preoperative staging with breast MRI in women younger than age 56 years altered the treatment plan in 18 % of the patients. Although a higher MRI-related conversion rate from breast conservation to mastectomy was found, the final numbers of mastectomies did not differ between the two groups. The breast reoperation rate in the MRI group was significantly reduced.  相似文献   
48.

Purpose

Tacrolimus (Tac) and cyclosporine (CsA) are mainly metabolized by CYP3A4 and CYP3A5. Several studies have demonstrated an association between the CYP3A5 genotype and Tac dose requirements. Recently, CYP3A4, PPARA, and POR gene variants have been shown to influence CYP3A metabolism. The present study investigated potential associations between CYP3A5*3, CYP3A4*22, PPARA c.209-1003G>A and c.208?+?3819A>G, and POR*28 alleles and dose-adjusted concentrations (C/D) of Tac and CsA in 177 renal transplant patients early post-transplant.

Methods

All patients (n?=?177) were genotyped for CYP3A4*22, CYP3A5*3, POR*28, PPARA c.209-1003G>A, and PPARA c.208?+?3819A>G using real-time polymerase chain reaction (PCR) and melting curve analysis with allele-specific hybridization probes or PCR restriction fragment length polymorphisms (RFLP) methods. Drug concentrations and administered doses were retrospectively collected from patient charts at Oslo University Hospital, Rikshospitalet, Norway. One steady-state concentration was collected for each patient.

Results

We confirmed a significant impact of the CYP3A5*3 allele on Tac exposure. Patients with POR*28 and PPARA variant alleles demonstrated 15 % lower (P?=?0.04) and 19 % higher (P?=?0.01) Tac C0/D respectively. CsA C2/D was 53 % higher among CYP3A4*22 carriers (P?=?0.03).

Conclusion

The results support the use of pre-transplant CYP3A5 genotyping to improve initial dosing of Tac, and suggest that Tac dosing may be further individualized by additional POR and PPARA genotyping. Furthermore, initial CsA dosing may be improved by pre-transplant CYP3A4*22 determination.  相似文献   
49.
50.

Background

Stroke lesions might alter pain processing and modulation by affecting the widely distributed network of brain regions involved. We aimed to compare pain tolerance in stroke survivors and stroke-free persons in the general population, with and without chronic pain.

Methods

We included all participants of the sixth and seventh wave of the population-based Tromsø Study who had been tested with the cold pressor test (hand in cold water bath, 3°C, maximum time 106 s in the sixth wave and 120 s in the seventh) and who had information on previous stroke status and covariates. Data on stroke status were obtained from the Tromsø Study Cardiovascular Disease Register and the Norwegian Stroke Register. Cox regression models were fitted using stroke prior to study attendance as the independent variable, cold pressor endurance time as time variable and hand withdrawal from cold water as event. Statistical adjustments were made for age, sex, diabetes, hypertension, hyperlipidaemia, body mass index and smoking.

Results

In total 21,837 participants were included, 311 of them with previous stroke. Stroke was associated with decreased cold pain tolerance time, with 28% increased hazard of hand withdrawal (hazard ratio [HR] 1.28, 95% CI 1.10–1.50). The effect was similar in participants with (HR 1.28, 95% CI 0.99–1.66) and without chronic pain (HR 1.29, 95% CI 1.04–1.59).

Conclusions

Stroke survivors, with and without chronic pain, had lower cold pressor pain tolerance, with possible clinical implications for pain in this group.

Significance

We found lower pain tolerance in participants with previous stroke compared to stroke-free participants of a large, population-based study. The association was present both in those with and without chronic pain. The results may warrant increased awareness by health professionals towards pain experienced by stroke patients in response to injuries, diseases and procedures.  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