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   2323篇
  免费   94篇
  国内免费   21篇
耳鼻咽喉   50篇
儿科学   211篇
妇产科学   33篇
基础医学   278篇
口腔科学   24篇
临床医学   160篇
内科学   409篇
皮肤病学   70篇
神经病学   157篇
特种医学   51篇
外科学   405篇
综合类   61篇
一般理论   2篇
预防医学   98篇
眼科学   97篇
药学   174篇
中国医学   5篇
肿瘤学   153篇
  2024年   3篇
  2023年   26篇
  2022年   64篇
  2021年   108篇
  2020年   50篇
  2019年   62篇
  2018年   86篇
  2017年   74篇
  2016年   118篇
  2015年   80篇
  2014年   129篇
  2013年   131篇
  2012年   200篇
  2011年   185篇
  2010年   118篇
  2009年   80篇
  2008年   136篇
  2007年   122篇
  2006年   119篇
  2005年   124篇
  2004年   96篇
  2003年   93篇
  2002年   72篇
  2001年   15篇
  2000年   20篇
  1999年   13篇
  1998年   13篇
  1997年   17篇
  1996年   8篇
  1995年   17篇
  1994年   3篇
  1993年   8篇
  1992年   5篇
  1991年   9篇
  1990年   6篇
  1989年   3篇
  1988年   3篇
  1984年   2篇
  1976年   2篇
  1973年   1篇
  1971年   1篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1946年   1篇
  1945年   1篇
  1943年   1篇
  1940年   1篇
  1930年   1篇
排序方式: 共有2438条查询结果,搜索用时 31 毫秒
91.
92.
INTRODUCTIONTraumatic abdominal wall hernia (TAWH) is a rare entity. Most cases occur in children, following an injury from the bicycle handle bar. In adults, it usually results from road traffic accidents (RTA). We present one of the largest reported cases of TAWH following RTA managed by delayed mesh repair.PRESENTATION OF CASEA 35 yr old obese male with RTA was diagnosed with TAWH with 19 cm × 15 cm defect in left flank. As there were no intra abdominal injuries and overlying skin was abraded, he was planned for elective repair after 6 months. On exploration a defect of 30 cm × 45 cm was found extending from midline anteriorly to 8 cm short of midline posteriorly in transverse axis and costal margin to iliac crest in craniocaudal axis. After restoration of bowel into abdominal cavity, primary closure or even approximation of muscular defect was not possible thus a mesh closure using 60 cm × 60 cm prolene mesh in subcutaneous plane was done. After 4 months follow up, patient is healthy and has no recurrence.DISCUSSIONEmergent surgical management of TAWH is usually favoured due to high incidence of associated intra abdominal injuries. Delayed repair may be undertaken in selected cases.CONCLUSIONTAWH, although rare, should be suspected in cases of RTA with abdominal wall swellings. With time, the hernia defect may enlarge and muscles may undergo atrophy making delayed repair difficult.  相似文献   
93.
Of the 74 immunocompetent patients diagnosed between July 2004 and June 2011 at the North Shore University Hospital and Long Island Jewish Medical Center with primary central nervous system lymphoma, 71 (95.9%) had diffuse large B-cell lymphomas (DLBCL). The median patient age was 68 years (range: 19–87 years) with a slight male preponderance (1.1:1). The overall median survival time was 21 months. For patients older than 70 years, the median survival time was 8 months while for those 70 years or younger, the median survival time was 27 months (p < 0.01). Female patients had a worse prognosis than male patients (p < 0.05, median survival time, 17 months compared to 23 months). We had enough data from 52 of these 71 patients to define the lymphomas as either germinal center B-cell-like (GCB) or activated B-cell-like (ABC) DLBCL. Of these 52 patients, 42 (80.8%) had ABC DLBCL while only 10 (19.2%) had GCB DLBCL. The patients in the GCB subgroup seemed to survive longer than the patients in the ABC subgroup, although the difference did not reach statistical significance. No statistically significant difference in overall survival was seen between patients with BCL-6 positive or negative DLBCL; or between patients with BCL-2 positive or negative DLBCL.  相似文献   
94.
There is an increasing awareness for recognition of sleep disorders in India; however, there is still a huge gap in the number of people suffering from various sleep disorders, in the community versus those visiting hospital clinics for the same. Ours is a neurology services-based sleep disorders clinic, which has evolved successfully over the last decade. In this study, we aimed to evaluate the changes in referral patterns and distribution of various sleep disorders in the patients presenting to the clinic.

Materials and Methods:

This is a retrospective chart review-based study on all patients seen over an 8-year period, divided into 2 groups comprising of patients seen during the first 4 years versus those seen over the next 4 years. Only those patients who had the sleep disorder as their presenting manifestation and those who had been formally interviewed with a pre-structured questionnaire detailing about the main features of the common sleep disorders according to the ICSD-R were included. Patients, in whom the sleep disorder could be clearly attributable to another neurological or systemic disorder, were excluded. Statistical analysis was carried out to identify the differences between the two groups as regards the distribution of various sleep disorders and other clinical data.

Results:

Among 710 patients registered in the clinic, 469 were included for analysis and 222 patients formed group 1 while 247 formed group 2. The main differences observed were in the form of a clear increase in the percentage of patients with sleep-related breathing disorders, sleep-related movement disorder, and the hypersomnias on comparison of distribution over the first 4 years versus the last 4 years; while a clear decline was seen in the number of patients with insomnia and parasomnias. A 3-fold increase was observed in the number of patients in whom polysomnography was obtained.

Conclusion:

The distribution of various sleep disorders as seen in a neurology service-based sleep clinic is demonstrated in this study. Increasing referrals for sleep-disordered breathing, restless legs syndrome, and fewer referrals for insomnia and parasomnias might reflect on changing physician and patient awareness in our community.  相似文献   
95.
Our aim was to compare the use of a conventional rotary handpiece and a Piezosurgical unit for extraction of lower third molars. We studied 40 patients, who were allocated alternately to have the third molar removed with either the handpiece or the Piezosurgical unit. Pain, trismus, and oedema were evaluated at baseline and then postoperatively, together with paraesthesiae, on postoperative days 1, 3, 5, 7, and 15. Damage to surrounding tissue was checked on the same day whereas dry socket was evaluated from postoperative day 3 onwards. More patients complained of pain in the conventional group, they also required more analgesics, and they developed trismus more often than in the Piezosurgery group. There was also significantly more postoperative swelling in the conventional group. Patients were also evaluated using the subjective Postoperative Symptom Severity (PoSSe) scale. Our results suggest that apart from some inherent limitations with the Piezotome, it is a valuable alternative for extraction of third molars.  相似文献   
96.
Diabetes mellitus (DM) is a gradually rising metabolic disease which is currently affecting millions of people worldwide. Diabetes is associated with various complications like nephropathy, neuropathy, retinopathy, diabetic foot, cognitive impairment, and many more. Evidence suggests that cognitive dysfunction is a rising complication of diabetes which adversely affects the brain of patients suffering from diabetes. Age-related memory impairment is a complication having its major effect on people suffering from diabetes and Alzheimer's. Patients suffering from diabetes are at two times higher risk of developing cognitive dysfunction as compared with normal individuals. Multiple factors which are involved in diabetes related complications are found to play a role in the development of neurodegeneration in Alzheimer's. The problem of insulin deficiency and insulin resistance is well reported in diabetes but there are many studies which suggest dysregulation of insulin levels as a reason behind the development of Alzheimer's. As the link between diabetes and Alzheimer disease (AD) is deepening, there is a need to understand the plausible tie-ins between the two. Emerging role of major factors like insulin imbalance, advanced glycation end products and micro-RNA's involved in diabetes and Alzheimer's have been discussed here. This review helps in understanding the plausible mechanism underlying the pathophysiology of amyloid beta (Aβ) plaque formation and tau hyperphosphorylation as well provides information about studies carried out in this area of research. The final thought is to enhance the scientific knowledge on this correlation and develop future therapeutics to treat the same.  相似文献   
97.

Objectives

To assess the preoperative serum levels of CA 125 with its diagnostic role and to evaluate the p53 expression in patients of primary ovarian neoplasms. We also wished to judge their relationship with other parameters like clinical staging and histopathologic tumor type.

Materials and Methods

The present study was conducted on 86 patients during the study period of 2.5 years. Preoperative CA 125 levels were evaluated by an automated immunoassay analyzer. p53 expression was judged immunohistochemically with pre-diluted monoclonal antibody. An objective scoring was done depending on distinct nuclear immunopositivity.

Results

Median value of preoperative CA 125 levels was 32 U/mL in benign surface epithelial-stromal tumors (BSEST), 53 U/mL in borderline surface epithelial-stromal tumors (BOT), 346 U/mL in malignant surface epithelial-stromal tumors (MSEST) and 560 U/mL in serous adenocarcinomas (SAC). Most of ovarian tumors were in the FIGO stage I (64 cases, 74.4%), but higher stages (II, III, IV) were observed mostly in MSESTs. SACs displayed the maximum p53 expression. Considering the cut-off value of more than 35 U/mL in CA 125 levels, the sensitivity to diagnose MSESTs was 94.7%. Preoperative CA 125 levels strongly and positively correlated with FIGO staging and p53 expression. Similarly p53 expression strongly and positively correlated with FIGO staging and histopathological categories.

Conclusion

Higher values of preoperative CA 125 levels and higher expression p53 are associated with MSESTs and BOTs especially of serous type. They strongly correlate with each other and with tumor stage. But there is no serum CA 125 concentration that can clearly differentiate benign and malignant ovarian masses.  相似文献   
98.
99.
100.

Objective

To evaluate the efficacy of single oral mega-dose of Vitamin D3 for treatment and prevention of pneumonia in underfive children.

Design

Randomized, double blind, placebo-controlled trial.

Setting

Tertiary-care hospital.

Participants

324 children (of 980 assessed) between 6 mo-5 y age (median (IQR): 12 (7,19.8) mo) with WHO-defined severe pneumonia. Of these, 126 (39%) were vitamin D deficient (serum 25(OH)D <12 ng/mL).

Intervention

100,000 IU of oral cholecalciferol (n= 162) or placebo (n= 162) in single dose, administered at enrolment.

Outcome variables

Primary: Time to resolution of severe pneumonia and proportion of children having recurrence of pneumonia in next 6 months; Secondary: Change in serum levels of 25(OH)D; immunoglobulins IgA, IgG, IgM, and cathelicidin 2 weeks following supplementation; and time taken for overall resolution of illness.

Results

Median (95% CI) time for resolution of severe pneumonia was 30 (29, 31) h in the vitamin D group as compared to 31 (29,33) h in the placebo group [adjusted hazard ratio (95% CI): 1·39 (1·11, 1·76); P=0·005]. The risk of recurrence of pneumonia in next 6 months was comparable in the two groups [placebo: 36/158 (22·8%); vitamin D: 39/156 (25%); RR (95% CI): 1·13 (0·67,1·90); P=0·69]. Proportion of vitamin D deficient children declined from 38% to 4% in the supplementation group, and from 41% to 33% in the placebo group, two weeks after supplementation. There was no significant effect of vitamin D supplementation on serum levels of cathelicidin, IgA and IgG. The time taken for complete recovery from pneumonia, duration of hospitalization, and fever clearance time were comparable for the two groups. No adverse event was noted related to the intervention.

Conclusion

There is no robust evidence of a definite biological benefit, either for therapy or prevention, to suggest a routine megadose supplement of vitamin D3 for under-five children with severe pneumonia.
  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