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   1809篇
  免费   105篇
  国内免费   14篇
耳鼻咽喉   20篇
儿科学   123篇
妇产科学   96篇
基础医学   199篇
口腔科学   110篇
临床医学   120篇
内科学   327篇
皮肤病学   41篇
神经病学   130篇
特种医学   65篇
外科学   245篇
综合类   33篇
预防医学   65篇
眼科学   124篇
药学   67篇
中国医学   6篇
肿瘤学   157篇
  2023年   16篇
  2022年   26篇
  2021年   48篇
  2020年   35篇
  2019年   36篇
  2018年   50篇
  2017年   38篇
  2016年   59篇
  2015年   71篇
  2014年   84篇
  2013年   108篇
  2012年   158篇
  2011年   134篇
  2010年   74篇
  2009年   75篇
  2008年   138篇
  2007年   142篇
  2006年   138篇
  2005年   127篇
  2004年   107篇
  2003年   82篇
  2002年   72篇
  2001年   26篇
  2000年   14篇
  1999年   14篇
  1998年   5篇
  1997年   1篇
  1996年   7篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   11篇
  1991年   4篇
  1990年   7篇
  1989年   2篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1980年   1篇
  1979年   2篇
  1975年   1篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
排序方式: 共有1928条查询结果,搜索用时 15 毫秒
991.
In order to identify the characteristics of patients with hematological malignancies (HM) in the presence/suspicion of any accompanying infectious disease, and to find the predictors of mortality in this group, hospital charts of patients with HM consulted by the Infectious Diseases (ID) team for signs/symptoms of any infection between January 1, 1997 and December 31, 2001 were retrospectively reviewed. A total of 1,132 consultations were done for 641 patients: 59.4% of the patients were male and the mean (±standard deviation) age of the study participants was 47.9±1.4 years. The most common underlying diseases were non-Hodgkins lymphoma (30.9%), acute myelogenous leukemia (26.2%), and multiple myeloma (10.9%). Clinically and microbiologically documented infections and fever of unknown origin were observed in 43.3%, 38.1%, and 18.5% of the participants, respectively. Bloodstream infections were detected in 134 episodes (20.9%): 56.5% were caused by gram-negative microorganisms. In logistic regression analysis, the presence of pneumonia (OR 7.56, 95% CI 4.84–12.486), invasive fungal infection (OR 4.12, 95% CI 1.78–9.55), relapse or recent diagnosis of the underlying disease (OR 2.82, 95% CI 1.53–5.21) and neutropenia (OR 2.70, 95% CI 1.70–4.31) were identified as statistically significant predictors of mortality.  相似文献   
992.
993.
994.
Dialysis remains the most common treatment for end‐stage renal disease (ESRD). Although the increased risk of cancer after renal transplant is well documented, there is less certainty about the risk of cancer in patients treated only with dialysis. From 1997 to 2002, 262 ESRD patients received a Pap test at Ba?kent University. The smears of 149 patients who had ESRD for more than 9 months were compared with the smears of 150 otherwise healthy patients. All of the Pap smears were re‐examined according to Bethesda 2001 criteria. The mean age of the patients was 42.88 years. Regarding micro‐organisms, no statistically significant difference between the groups were observed. In 36 Pap smears, a shift in flora suggestive of bacterial vaginosis was detected. There were statistically significant differences between the groups. When age was considered as a marker of atrophy, atrophy in patients younger than 50 years was statistically different between the groups. Also, we determined that the shift in flora suggestive of bacterial vaginosis and atrophy in patients aged younger than 50 years did not depend on the length of hemodialysis. Of 13 patients (4.3%) who had epithelial cell abnormalities there were not statistically significant differences between the groups. In conclusion, according to our study, CRF seems not to be a predictive factor for cervical cancer. Shift in flora suggestive of bacterial vaginosis and atrophy in patients aged younger than 50 years might be the natural effects of uremia, and they appear not to be dependent on the length of the hemodialysis period. Diagn. Cytopathol. 2008;36:776–779. © 2008 Wiley‐Liss, Inc.  相似文献   
995.
The magnitude of anti-tuberculosis drug resistance in Bangladesh is not precisely known. We studied the drug resistance patterns of Mycobacterium tuberculosis in an urban and a rural area of Bangladesh. A tuberculosis (TB) surveillance system has been set up in a population of 106,000 in rural Matlab and in a TB clinic in urban Dhaka. Trained field workers interviewed all persons > or =15 y at Matlab to detect suspected cases of tuberculosis (cough >21 d) and sputum samples were examined for acid-fast bacilli (AFB). The first 3 AFB positive patients daily from the urban clinic were included. AFB positive cases diagnosed between June 2001 and June 2003 from both settings were cultured and drug susceptibility tests were performed. Of 657 isolates, resistance to 1 or more drugs was observed in 48.4% of isolates. Resistance to streptomycin, isoniazid, ethambutol and rifampicin was observed in 45.2%, 14.2%, 7.9% and 6.4% of isolates, respectively. Multidrug resistance was observed in 5.5% of isolates. It was significantly higher among persons who previously had received tuberculosis treatment of > or =1 month (15.4% vs 3.0%, adjusted OR: 6.12, 95% CI: 3.03-12.34). The magnitude of anti-tuberculosis drug resistance in Bangladesh is high. Further evaluation is needed to explain the high proportion of streptomycin resistant M. tuberculosis. Appropriate measures to control and prevent drug resistant tuberculosis in Bangladesh to reduce mortality and transmission are warranted.  相似文献   
996.
Objective The incidence of diabetes mellitus in patients with primary hyperparathyroidism and, conversely, primary hyperparathyroidism in diabetic patients are approximately threefold higher than the respective expected prevalence in the general populace. The diagnosis is straightforward when the patient presents hypercalcemia and inappropriately elevated serum parathyroid hormone (PTH) levels. We report a case of parathyroid adenoma in a diabetic patient with persistent hypercalcemia and normal PTH levels. Patient A 50-year-old female patient who was referred to our outpatient clinic presented with persistent hypercalcemia (serum Ca levels between 10.5 and 11 mg/dl) with a normal serum intact PTH level of 46.1 pg/ml. Her blood pressure was 120/80 mmHg, and she was being treated with antihypertensive therapy. Her HbA1c was 7.2%, and her triglycerides were in the normal range. A bone densitometry exam revealed osteopenia of radius −1.39, femoral neck −1.39, and the total hip −1.04. A neck ultrasound revealed a mass of 13 mm next to the inferior and posterior of the right thyroid lobe. A dual phase Tc-99m-sestamibi scan revealed an area of increased uptake in the same region, which is indicative of a parathyroid adenoma. The parathyroid adenoma was removed, which resulted in the achievement of normocalcemia. Conclusion Diabetic patients should be evaluated for hyperparathyroidism as associated hypertension can complicate the course of the disease. These patients should be evaluated for primary hyperparathyroidism when they exhibit persistent hypercalcemia and when clinical suspicion is aroused even if the serum PTH levels are within the normal range.  相似文献   
997.
998.
McCune-Albright syndrome is a rare disorder caused by an activating mutation in the gene (GNAS1) encoding the subunit of the G protein. This syndrome is characterized by polyostotic fibrous dysplasia, café-au-lait pigmentation, and multiple endocrine hyperfunction. A 29-year-old male with polyostotic fibrous dysplasia, café-au-lait pigmentations, and pituitary adenoma is presented in this report. The patient had accompanying bipolar affective disorder, which might have been caused by the underlying genetic abnormality.  相似文献   
999.
Transcranial Doppler (TCD) With Transfusions Changing to Hydroxyurea (TWiTCH) trial is a randomized, open‐label comparison of hydroxycarbamide (also termed hydroxyurea) versus continued chronic transfusion therapy for primary stroke prevention in patients with sickle cell anaemia (SCA) and abnormal TCD. Severity and location of iron overload is an important secondary outcome measure. We report the baseline findings of abdominal organ iron burden in 121 participants. At enrollment, patients were young (9·8 ± 2·9 years), predominantly female (60:40), and previously treated with transfusions (4·1 ± 2·4 years) and iron chelation (3·1 ± 2·1 years). Liver iron concentration (LIC; 9·0 ± 6·6 mg/g dry weight) and serum ferritin were moderately elevated (2696 ± 1678 μg/l), but transferrin was incompletely saturated (47·2 ± 23·6%). Spleen R2* was 509 ± 399 Hz (splenic iron ~13·9 mg/g) and correlated with LIC (r2 = 0·14, P = 0·0008). Pancreas R2* was increased in 38·3% of patients but not to levels associated with endocrine toxicity. Kidney R2* was increased in 80·7% of patients; renal iron correlated with markers of intravascular haemolysis and was elevated in patients with increased urine albumin‐creatinine ratios. Extra‐hepatic iron deposition is common among children with SCA who receive chronic transfusions, and could potentiate oxidative stress caused by reperfusion injury and decellularized haemoglobin.  相似文献   
1000.
The present study has been designed to determine melatonin levels in type 2 diabetic patients and test the relationship between the autonomic nervous system and melatonin dynamics. Thirty-six type 2 diabetic patients and 13 age-matched healthy subjects were recruited for the study. Circadian rhythm of melatonin secretion was assessed by measuring serum melatonin concentrations between 02:00-04:00 and 16:00-18:00 hr. Melatonin dynamics were re-evaluated with respect to autonomic nervous system in diabetic patients with autonomic neuropathy who were diagnosed by the cardiovascular reflex tests, heart rate variability (HRV), and 24-hr blood pressure monitoring. Nocturnal melatonin levels and the nocturnal melatonin surge were low in the diabetic group (P = 0.027 and 0.008 respectively). Patients with autonomic neuropathy revealed decreased melatonin levels both at night and during day when compared with healthy controls (P < 0.001 and 0.004 respectively) while the melatonin dynamics were similar to controls in patients without autonomic neuropathy. Nocturnal melatonin level was positively correlated with nocturnal high and low frequency components of HRV (P = 0.005 and 0.011 respectively) and systolic and diastolic blood pressures at night (P = 0.002 and 0.004 respectively) in patients with autonomic neuropathy. We found a negative correlation between nocturnal melatonin levels and the degree of systolic blood pressure decrease at night (r = -0.478, P = 0.045). As a conclusion this study has shown that circadian rhythm of melatonin secretion is blunted in type 2 diabetic patients and there is a complex relationship between various components of autonomic nervous system and melatonin secretion at night. Among the patients with autonomic neuropathy those with more preserved HRV and the systolic nondippers (<10% reduction in blood pressure during the night relative to daytime values) have more pronounced melatonin surge at night.  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