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   805篇
  免费   32篇
  国内免费   11篇
耳鼻咽喉   22篇
儿科学   30篇
妇产科学   23篇
基础医学   83篇
口腔科学   21篇
临床医学   63篇
内科学   176篇
皮肤病学   26篇
神经病学   39篇
特种医学   11篇
外科学   142篇
综合类   21篇
一般理论   1篇
预防医学   45篇
眼科学   19篇
药学   57篇
中国医学   10篇
肿瘤学   59篇
  2023年   8篇
  2022年   15篇
  2021年   63篇
  2020年   30篇
  2019年   35篇
  2018年   37篇
  2017年   24篇
  2016年   26篇
  2015年   21篇
  2014年   41篇
  2013年   39篇
  2012年   68篇
  2011年   67篇
  2010年   40篇
  2009年   36篇
  2008年   36篇
  2007年   26篇
  2006年   24篇
  2005年   25篇
  2004年   33篇
  2003年   27篇
  2002年   24篇
  2001年   7篇
  2000年   8篇
  1999年   3篇
  1998年   2篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1992年   3篇
  1991年   1篇
  1989年   3篇
  1988年   2篇
  1987年   1篇
  1986年   7篇
  1985年   10篇
  1984年   6篇
  1983年   4篇
  1982年   7篇
  1981年   4篇
  1980年   2篇
  1979年   6篇
  1978年   6篇
  1977年   2篇
  1976年   3篇
  1975年   2篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有848条查询结果,搜索用时 15 毫秒
1.
Conclusions: This study revealed a significant correlation between red-green-blue (RGB) values of tympanic membrane (TM) images and the presence of effusion in the middle ear. These results confirm that endoscopic RGB evaluation is a rapid and non-invasive procedure yielding objective results. Objective: To investigate, in cases of otitis media with effusion (OME), the correlation of the TM color changes with the presence and viscosity of the effusion in the middle ear. Methods: Endoscopic images of the TMs of 52 patients (group 1) and 52 healthy controls (group 2) were taken during their otologic examinations. RGB values of particular points were measured on the TM images of both groups. Additionally, in group 1 the viscosity of each effusion taken by paracentesis during surgery was also measured intraoperatively with a viscometer. Patients with viscosity values lower and higher than 450 cP (centipoise) were subdivided into groups 1a and 1b, respectively. Results: Study and control groups were comparable regarding the number of patients and their mean ages (p > 0.05). Statistically significant differences were found in RGB values of the TM between groups 1 and 2, but not between groups 1a and 1b.  相似文献   
2.
We present our experience over 6 years with the use of uncemented total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) with a mean follow-up of 3 years. In a 6-year period, 26 THAs were performed in 19 patients with Hartofilakidis grades 2 and 3 dislocation of the hips. Out of 19 patients, seven had bilateral dislocations. Uncemented acetabular and femoral components were used in all patients. Patients with a minimum follow-up of 1 year were included in the study. The average age at the time of surgery was 38 (range 20–69) years. Approaches used include trochanteric osteotomy in 14 (54%) patients and a lateral approach in 12 (46%) patients. In addition, subtrochanteric osteotomy was performed in four (15%) patients. A Mallory-head femoral stem was used in 15 (58%) patients; a DDH femoral stem was in nine (35%), and the S-ROM femoral prosthesis in two (8%). A Mallory head acetabular shell was used in all cases, a 22.2-mm chrome cobalt head was used in 18 (69%), and a 28-mm chrome cobalt head was used in eight (31%). The average follow-up was 3 (range 1–6) years. The Harris hip score (HHS) improved in the cohort from a mean preoperative score of 51 to a mean postoperative score of 86 (p<0.05). The mean preoperative SF36v2 score was 42 compared to postoperatively of 67(p<0.05). The complication rate was 11% with nonunion of a subtrochanteric osteotomy in one patient, dislocation in one, and trochanteric bursitis due to fracture of Dall-Miles cables in one. THA for DDH is a technically demanding procedure. This short-term follow-up of THA for DDH using uncemented implants is encouraging for arthrosis secondary to DDH. It provides better function compared to arthrodesis or excision arthroplasty, especially in young individuals. A long-term follow-up is required in order to establish the role of this management strategy.  相似文献   
3.
Neural representations created in the absence of external sensory stimuli are referred to as imagery, and such representations may be augmented by reenactment of sensorimotor processes. We measured nasal airflow in human subjects while they imagined sights, sounds and smells, and only during olfactory imagery did subjects spontaneously enact the motor component of olfaction--that is, they sniffed. Moreover, as in perception, imagery of pleasant odors involved larger sniffs than imagery of unpleasant odors, suggesting that the act of sniffing has a functional role in creating of olfactory percepts.  相似文献   
4.
5.
Parathyroid Hormone-related Protein (PTHrP) is a highly evolutionarily conserved, stretch-regulated gene that is necessary for the embryonic transition from branching morphogenesis to alveolization of the lung. It is expressed throughout vertebrate phylogeny, beginning with its expression in the fish swim bladder as an adaptation to gravity; microgravity downregulates the expression of PTHrP by alveolar type II cells, and by bones from rats exposed to 0 x g, suggesting that PTHrP signaling has been exploited for adaptation to 1 x g. PTHrP/PTHrP receptor signaling is upregulated by stretching alveolar type II cells and intersitial lung fibroblasts, whereas overdistension downregulates PTHrP and PTHrP receptor mRNA, further suggesting an evolutionary adaptation. Both surfactant homeostasis and alveolar capillary perfusion are under PTHrP control, indicating that alveolization and ventilation/perfusion matching may have evolved under the influence of PTHrP signaling. Phylogenetic analysis of lung evolution reflects the concomitant increases in alveolar surface area and surfactant production by "amplifying" the PTHrP pathway signal. This mechanism is discussed as a function of increased evolutionary respiratory demand to keep up with the increased metabolic demand for oxygen, and the role of the PTHrP signaling mechanism in leveraging this process.  相似文献   
6.
The aim of this paper is twofold. Firstly, to investigate the potential benefits of online health communities (OHCs) for informal caregivers by conducting a systematic literature review. Secondly, to identify the relationship between the potential benefits of OHCs and resilience factors of older adults. Performing a thematic analysis, we identified the potential benefits of OHCs for informal caregivers of older adults, including two salient themes: (a) caregivers sharing and receiving social support and (b) self and moral empowerment of caregivers. Then, we uncovered how these potential benefits can support resilience of older adults. Our findings show that sharing and receiving of social support by informal caregivers, and self and moral empowerment of informal caregivers in OHCs, can support four resilience factors among older adults, including self-care, independence, altruism and external connections. This review enables a better understanding of OHCs and Gerontology, and our outcomes also challenge the way healthcare and aged-care service providers view caregivers and older adults. Furthermore, the identified gap and opportunities would provide avenues for further research in OHCs.  相似文献   
7.
Clinical experience, and a pathology study, of 184 women on Neogynon (.25 mg d-norgestrel and .05 mg of 17-ethinyl estradiol, micro 20) was assessed for a total of 3129 cycles. 53 women were nursing babies before use of the pill, and 44 continued to do so throughout pill usage. Endometrial biopsies were taken premenstrually, during the period of full hormonal effect, for 40 cases before and then 6-12 months after initiation of pill usage; biopsies were studied for effect of the combined steroid on the building up of endometrium. The combination pill was 100% effective, with no failures. 23 cases (12.5%) failed to continue through the 18th cycle. 4 cases stopped after the 2nd cycle and 6 more after the 4th; the remaining stopped after the 12th cycle. No change in menstrual pattern was noticed in 136 (73.9%) of the cases; 14 presented with menorrhagia and endometrial biopsy of one of these showed regressive and mixed endometrial changes. 2 cases of intermenstrual spotting were reported. Hypomenorrhea was reported in 16 cases. Side effects were generally effects on the central nervous system: 7 cases of headache and dizziness, 7 cases of mild depression, and 3 cases of sexual anorexia. No gastrointestinal side effects were reported. 44 cases (of 53) continued lactation, and 9 noticed a progressive decrease in the amount of milk produced. 8 cases gained weight and 13 lost, 2 enough to quit using the pills. Hair loss was a noticeable complaint in 5 cases. Endometrial biopsies revealed grades of arrest of endometrial development. 85% showed a resting endometrial pattern, whereas 15% were atrophic. Endometrial response was rather irregular and mainly of the mixed type in 90% of the cases and about 10% were proliferative.  相似文献   
8.
Management of Head and Neck Cancers poses a challenge inspite of several advances because of poor success in terms of response rate, survival and reduced morbidity of the patients. In the present study 30 untreated histologically proven cases of head and neck cancers were subjected to weekly radiotherapy with adjuvant chemotherapy (cisplatin 30 mg/m2 intravenously). This study group was compared with a group of 30 patients who were given only radiotherapy. Results have shown that combination of chemotherapy with radiotherapy gives a significantly better results in tumour as well as nodal response with minimal toxicities.  相似文献   
9.
10.
The house fly, Musca domestica L., is one of the major pests in dairy operations that has developed resistance to a number of insecticides with different modes of action. Adult house fly populations from six dairies in Punjab, Pakistan were evaluated for resistance to insecticides with novel modes of action (abamectin, emamectin benzoate, fipronil, imidacloprid, indoxacarb, and spinosad). Significant levels of resistance to most of the insecticides tested were observed in the present study. For avermectins at LC50 level, the resistance ratios were in the range of 38.40 to 94.44-fold for abamectin and 13.16 to 36.30-fold for emamectin benzoate. Fipronil LC50 resistance ratios exceeded 10-fold in three house fly populations, while all the populations had >10-fold resistance ratios for imidacloprid. Indoxacarb and spinosad had the lowest resistance ratios that ranged from 3.02 to 7.12-fold for indoxacarb and 2.91 to 9.0-fold for spinosad. As the resistance to fipronil, indoxacarb, and spinosad are emerging, therefore these chemicals should be used cautiously in management programs to retain the efficacy for longer times.  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