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   603篇
  免费   35篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   36篇
妇产科学   53篇
基础医学   70篇
口腔科学   25篇
临床医学   52篇
内科学   120篇
皮肤病学   18篇
神经病学   36篇
特种医学   8篇
外科学   73篇
综合类   4篇
预防医学   24篇
眼科学   17篇
药学   46篇
中国医学   3篇
肿瘤学   57篇
  2024年   2篇
  2023年   2篇
  2022年   7篇
  2021年   34篇
  2020年   13篇
  2019年   21篇
  2018年   24篇
  2017年   16篇
  2016年   21篇
  2015年   26篇
  2014年   38篇
  2013年   40篇
  2012年   58篇
  2011年   86篇
  2010年   48篇
  2009年   21篇
  2008年   32篇
  2007年   45篇
  2006年   19篇
  2005年   22篇
  2004年   26篇
  2003年   17篇
  2002年   10篇
  2000年   1篇
  1999年   1篇
  1998年   5篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1993年   2篇
  1990年   1篇
排序方式: 共有643条查询结果,搜索用时 15 毫秒
81.
We report a 31 year old patient, presented with painful erection since 48 hours. There was no known predisposing factor on history and examination. Surgery for priapism is rarely indicated nowadays but conservative management failed to achieve detumescence in our case. So Winter’s shunt surgery was done which failed then a formal shunt was created between corpora cavernosa and spongiosum which also failed to achieve detumescence. After 4 days - a formal left side cavernosa saphenous shunt procedure was done and detumescence achieved within 24 hrs .Follow up showed good results.  相似文献   
82.
In the present study, porous PLGA microparticulate scaffolds (PMS_P), surface‐hydrolysed scaffolds (PMS_Hyd) and cytomodulin‐coupled scaffolds (PMS_CM) were prepared and characterized. After coupling the particles with cytomodulin, the size was reduced from 334 µm (span 0.53) to 278 µm due to hydrolysis, and contact angle also decreased from 70.87 ± 8.56 to 31.43 ± 7.43, indicating an increase in hydrophilicity. Surface roughness and pore density increased, along with an increase in surface area from 9.59 ± 0.36 to 16.82 ± 0.064 m2/g after attaching the biomolecule CM onto the PLGA particles. In vitro cell culture experiments on human dermal fibroblasts (HDFs) were performed for 21 days, in which MTT assay indicated two‐fold higher cell proliferation on PMS_Hyd than on PMS_CM; however, cell distribution, cell spreading and actin production were significantly higher on PMS_CM than on other scaffolds. Migration of cells from PMS_CM to a 2D plate was gradual but the migrated cells attained early confluence, indicating the preservation of normal cellular functions. In a full‐thickness wound mouse model, PMS_CM exhibited 80% wound closure within 2 weeks. Further, at the end of week 3, the inflammatory cell count in the PMS_CM group was reduced to one‐third of the control group, while in PMS_P and PMS_Hyd the extent of inflammation was much higher and more severe. In the case of PMS_CM, abundant fibroblast proliferation, early formation of the scar tissue, eschar formation and inward movement of the wound margins (a zipper‐like movement) towards the deeper layers of the skin suggested advanced wound healing. Cytomodulin‐coupled scaffolds ensured better cell spreading and migration and thus enabled rapid wound healing (see Supporting information, Figure S1). Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
83.
BackgroundThis analysis was conducted to identify the participant characteristics associated with noncompliance in an oral contraceptive (OC) clinical trial.Study DesignWe studied ovarian suppression among normal-weight and obese women during the use of levonorgestrel (LNG)-containing combination OCs. Participants underwent twice weekly phlebotomy during the study cycle and received up to $360 for participation. Along with other study assays, we analyzed 903 specimens from 181 women to measure LNG to assess OC compliance. Consistently undetectable LNG levels indicated noncompliance. To evaluate predictors of OC noncompliance during this study, we compared the characteristics of compliant and noncompliant participants using multivariable logistic regression. We assigned each participant to a relative poverty level based on US census data; all other individual characteristics came directly from participant responses during the baseline interview.ResultsOne hundred eighty-one women completed the study; 31 were noncompliant (17%). In multivariable analyses, poverty level was the strongest predictor of noncompliance. Compared with those women in the quartile with the lowest level of residential poverty, other women were far more likely to be noncompliant, especially women in the quartile with the greatest prevalence of poverty (adjusted odds ratio, 8.4; 95% confidence interval, 1.5–46.1). Additional factors associated with noncompliance were education level less than a bachelor's degree and Hispanic ethnicity. Other demographic and psychometric measures were not associated with compliance.ConclusionsWe found that noncompliance was strongly associated with residential poverty level, an indirect measure of individual income. In the United States, poverty is associated with female obesity, Hispanic ethnicity and low education, which were also associated here with noncompliance. Study compensation may motivate poor individuals to participate in clinical trials for income. Noncompliance in clinical trials, particularly differential noncompliance, jeopardizes study validity.  相似文献   
84.
Organophosphate pesticides are among the most widely used synthetic chemicals for controlling domestic and agricultural pests. Present study was aimed to evaluate the potential of chlorpyrifos, parathion and malathion, to disturb glutathione homeostasis in rat tissues and to find out whether the pre-feeding of antioxidant vitamins has some ameliorating effect on the pesticide-induced alterations. The results showed that these pesticides, alone or in combination, caused decrease in the levels of GSH and the corresponding increase in the levels of GSSG, decreasing the GSH/GSSG ratio. The results also showed NADPH/NADP(+) and NADH/NAD(+) ratios were also decreased in the rat tissues on pesticide exposure. These pesticides, alone or in combination, caused increase in the activities of glutathione reductase and glucose-6-phosphate dehydrogenase in all the rat tissues studied. The findings show that these pesticides generate oxidative stress and prior feeding of mixture of antioxidant vitamins tend to reduce the toxicities of these pesticides.  相似文献   
85.
This study examines understanding of living wills by patients, family members, and physicians. Questionnaires were used to examine whether each cohort understood patients' living wills regarding endotracheal intubation and cardiopulmonary rescuscitation (CPR). Of 4,800 patients admitted during the study period, 206 reported having living wills, all of which precluded intubation and CPR for "terminal conditions." Of 140 admitted to the general hospital wards, 17 (12%) wanted their living wills to preclude intubation/mechanical ventilation and 12 (8.6%) did not want resuscitation under any circumstances. Seven of 120 (6%) physicians and 4 of 108 family members would not intubate or perform CPR even if there was a chance of recovery. Of 88 patients with complete data (including physicians and family members), 29 (33%) wanted their living wills to block intubation/mechanical ventilation only if they were deemed terminal and 46 (52%) wanted the living will to block intubation even if there was a 10% chance of recovery. Thirteen (15%) wanted to block intubation even if the chance of recovery was > or = 50. Results were similar for wishes regarding CPR. These data suggest substantial differences of patient, physician, and family member understanding of living wills. Living wills did not reflect fully patients' expectations of receiving (or not receiving) life-sustaining modalities.  相似文献   
86.
Mehta A  Baker TA  Shoup M  Brownson K  Amde S  Doren E  Shah S  Kuo P  Angelats J 《American journal of surgery》2012,203(3):303-6; discussion 306-7
BackgroundSurgical therapy for advanced-stage pressure ulcers recalcitrant to healing is a widely accepted practice. The present study examined the incidence of wound recurrence after reconstruction with fasciocutaneous versus combined (biplanar) muscle and fasciocutaneous flaps.MethodsA retrospective review identified 90 nonambulatory patients with spinal cord injury who underwent reconstruction for persistent decubitus ulcers from 2002 to 2008. Electronic medical records were surveyed for patient comorbidities and postoperative complications. Statistical methods included the Fisher exact test and the Mann–Whitney U test with a 2-sided P value of less than .05.ResultsAmong 90 patients reviewed, 33% (n = 30) received fasciocutaneous flaps and 66% (n = 60) underwent biplanar reconstruction. Comorbidities were the same between cohorts with the exception of a greater prevalence of diabetes in the biplanar group (27% vs 50%; P < .05). The incidence of recurrence for biplanar flaps (25%) was significantly lower than for fasciocutaneous reconstruction (53%; P < .01).ConclusionsBiplanar flap reconstruction should be considered for chronically immobilized patients at high risk for recurrent decubitus ulceration.  相似文献   
87.
88.
Objectives: We studied the effect of body mass index (BMI) at peritoneal dialysis (PD) initiation on patient and technique survival and on peritonitis during follow-up.♦ Methods: We followed 328 incident patients on PD (176 with diabetes; 242 men; mean age: 52.6 ± 12.6 years; mean BMI: 21.9 ± 3.8 kg/m2) for 20.0 ± 14.3 months. Patients were categorized into four BMI groups: obese, ≥25 kg/m2; overweight, 23 - 24.9 kg/m2; normal, 18.5 - 22.9 kg/m2 (reference category); and underweight, <18.5 kg/m2. The outcomes of interest were compared between the groups.♦ Results: Of the 328 patients, 47 (14.3%) were underweight, 171 (52.1%) were normal weight, 53 (16.2%) were overweight, and 57 (17.4%) were obese at commencement of PD therapy. The crude hazard ratio (HR) for mortality (p = 0.004) and the HR adjusted for age, subjective global assessment, comorbidities, albumin, diabetes, and residual glomerular filtration rate (p = 0.02) were both significantly greater in the underweight group than in the normal-weight group. In comparison with the reference category, the HR for mortality was significantly greater for underweight PD patients with diabetes [2.7; 95% confidence interval (CI): 1.5 to 5.0; p = 0.002], but similar for all BMI categories of nondiabetic PD patients.Median patient survival was statistically inferior in underweight patients than in patients having a normal BMI. Median patient survival in underweight, normal, overweight, and obese patients was, respectively, 26 patient-months (95% CI: 20.9 to 31.0 patient-months), 50 patient-months (95% CI: 33.6 to 66.4 patient-months), 57.7 patient-months (95% CI: 33.2 to 82.2 patient-months), and 49 patient-months (95% CI: 18.4 to 79.6 patient-months; p = 0.015). Death-censored technique survival was statistically similar in all BMI categories. In comparison with the reference category, the odds ratio for peritonitis occurrence was 1.8 (95% CI: 0.9 to 3.4; p = 0.086) for underweight patients; 1.7 (95% CI: 0.9 to 3.2; p = 0.091) for overweight patients; and 3.4 (95% CI: 1.8 to 6.4; p < 0.001) for obese patients.♦ Conclusions: In our PD patients, mean BMI was within the normal range. The HR for mortality was significantly greater for underweight diabetic PD patients than for patients in the reference category. Death-censored technique survival was similar in all BMI categories. Obese patients had a greater risk of peritonitis.  相似文献   
89.
90.
Pseudoachondroplasia is a rare rhizomelic short-limbed skeletal dysplasia. Its inheritance is varied; autosomal dominant pattern and germline or somatic mutations can occur. Children at 2–3 years of age present with short height, gait disturbances, or limb deformities. Characteristic skeletal changes include shortening of long bones, predominantly of femur and humerus with irregular, flared metaphysis and fragmented epiphysis. Platyspondyly is also present, but the interpedicular distance is normal. The diagnosis is essentially based on imaging, and thus, it is important to be aware of the radiological features. Here, we report a case of two brothers where the elder sibling had classical radiological features of pseudoachondroplasia, whereas the younger one had early changes of this disorder.  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