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   3892篇
  免费   144篇
  国内免费   33篇
耳鼻咽喉   16篇
儿科学   60篇
妇产科学   39篇
基础医学   498篇
口腔科学   29篇
临床医学   760篇
内科学   926篇
皮肤病学   21篇
神经病学   303篇
特种医学   124篇
外国民族医学   1篇
外科学   490篇
综合类   17篇
预防医学   187篇
眼科学   86篇
药学   265篇
中国医学   7篇
肿瘤学   240篇
  2023年   10篇
  2022年   20篇
  2021年   35篇
  2020年   17篇
  2019年   32篇
  2018年   48篇
  2017年   47篇
  2016年   33篇
  2015年   61篇
  2014年   102篇
  2013年   124篇
  2012年   250篇
  2011年   292篇
  2010年   149篇
  2009年   168篇
  2008年   295篇
  2007年   295篇
  2006年   284篇
  2005年   307篇
  2004年   289篇
  2003年   311篇
  2002年   256篇
  2001年   44篇
  2000年   46篇
  1999年   46篇
  1998年   48篇
  1997年   36篇
  1996年   35篇
  1995年   44篇
  1994年   35篇
  1993年   22篇
  1992年   19篇
  1991年   34篇
  1990年   21篇
  1989年   16篇
  1988年   18篇
  1987年   17篇
  1986年   15篇
  1985年   12篇
  1984年   17篇
  1983年   9篇
  1982年   16篇
  1981年   15篇
  1980年   11篇
  1979年   22篇
  1978年   8篇
  1977年   8篇
  1976年   6篇
  1974年   4篇
  1973年   4篇
排序方式: 共有4069条查询结果,搜索用时 15 毫秒
1.
Diverticulosis is a common colonic disease in industrialized societies and its prevalence increases with age. Acute diverticulitis is defined by diverticular and peridiverticular inflammation and infection. For most patients, outpatient therapy is possible and hospitalization is only indicated if the patient is unable to eat, suffers from an acute attack, has complications or if symptoms fail to improve despite adequate outpatient therapy. The treatment of acute uncomplicated diverticulitis usually consists of broad-spectrum antibiotics covering both aerobic and anaerobic bacteria. Antimicrobial therapy is given for 7 to 10 days but the duration of the treatment can be longer if there are complications. If there is no clinical improvement within 2 or 3 days, repeat CT imaging is appropriate, as this may reveal an abscess, phlegmon or fistula, which might necessitate percutaneous drainage or surgery. The published literature does not support the recommendation of any prophylactic diet or medical treatment for reducing the risk of first or recurrent diverticulitis in patients with diverticulosis.  相似文献   
2.
BACKGROUND: Abnormal glucose tolerance is a frequent co-morbidity in cystic fibrosis patients (CF), and is associated with a worse prognosis. The objectives are to investigate (a) the relative contribution of insulinopenia and insulin resistance (IR) for glucose tolerance and (b) the association between various glucose parameters and CF clinical status. METHODS: Oral glucose tolerance tests were performed in 114 consecutive CF patients not known to be diabetic as well as 14 controls similar for age and BMI. RESULTS: Abnormal glucose tolerance was found in 40% of patients with CF: 28% had impaired glucose tolerance (IGT) and 12% had new cystic fibrosis related diabetes (CFRD). Compared to control subjects, all CF patients were characterized by an increased glucose excursion (AUC). While reduced early insulin release characterised CF, IGT and CFRD patients also present IR thus both mechanisms significantly contribute to glucose tolerance abnormalities. Increased glucose AUC and reduced early insulin release but not glucose tolerance categories were associated with a reduced pulmonary function (FEV(1)). CONCLUSION: In CF, early insulin secretion defect but also IR contribute to glucose intolerance. Early in the course of the disease, increased glucose AUC and reduced early insulin secretion are more closely associated with a worse clinical status than conventional glucose tolerance categories.  相似文献   
3.
OBJECTIVE: The aim of this paper is to assess the accuracy of an algorithm implemented by PRAXIM in the SURGETICS navigation station for detection of the hip center. This study will assess the robustness and accuracy of the algorithm in various clinical situations such as those involving non-sphericity of the femoral head, motion of the pelvis during hip center detection, and restricted range of motion. MATERIALS AND METHODS: The localization of the hip center, based on kinematics, relies on the recording of n successive positions of the femoral rigid body in the localizer reference system during a passive circumduction motion of the hip joint. Therefore, the shape of the clouds of points acquired may vary from one acquisition to the next. To allow a comprehensive study of the consequences of these variations for hip center detection, we developed a simulator to generate numerous clouds of points. Results given subsequently for each test are the values of the difference between the femoral mechanical axis computed with C(c), the computed hip center, and the same axis computed with C(o), the reference hip center. RESULTS: Test 1: Sensitivity to noise. The errors ranged from 3.33 E - 12 (SD 3.29E - 12) for a noise of 0 mm to 8.18E - 1 (SD - 7.05E - 1) for a noise of 15 mm. Test 2: Sensitivity to the shape of the acquisition motion. All trajectories gave an error < 1 degrees . Test 3: Sensitivity to restricted range of motion. No value > 1 degrees was found during this test. Test 4: Sensitivity to the distance between two points of the cloud. No value > 0.5 degrees was found during this test. Test 5: Sensitivity to the number of points included in the cloud. No value > 1 degrees was found during this test. CONCLUSIONS: The Surgetics algorithm is robust to noise, can compensate for pelvic motion, and can be used even in the case of restricted range of motion.  相似文献   
4.
The effects of scopolamine, an anticholinergic drug, of trimipramine, a tricyclic antidepressant with both anticholinergic and sedative properties, of diazepam and a placebo, on explicit memory and repetition priming were assessed using a free-recall task and a word-stem completion task. Forty-eight healthy volunteers took part in this double-blind study. Diazepam provoked a dissociation between free recall, which was profoundly impaired, and word completion, which was spared. No significant changes in memory performances were observed in the scopolamine group; however, a significant correlation between explicit and implicit memory performances was observed in this group. At the low dose used, the effects of trimipramine on memory were mild. The results suggest that the cholinergic system is involved in the priming effect.  相似文献   
5.
6.
[(123)I]Metaiodobenzylguanidine ([(123)I]MIBG) cardiac scintigraphy could be helpful to differentiate Parkinson's disease (PD) from multiple system atrophy (MSA), demonstrating that, in PD with autonomic failure but not in MSA, there is a myocardial postganglionic sympathetic dysfunction. To investigate whether this method is more sensitive than standard autonomic testing to detect early involvement of sympathetic cardiac efferent, we analyse MIBG myocardial uptake in 8 PD patients with normal autonomic testing (nondysautonomia PD group, NDPD) in comparison with 10 PD patients with abnormal autonomic testing (dysautonomia PD group, DPD) and 10 MSA patients. Global MIBG uptake was assessed using the ratio of [(123)I]MIBG uptake in the heart to the upper mediastinum (H/M) on planar scintigraphic data. Regional MIBG uptake was determined on two single photon emission tomography scans in regions of the left ventricle. The mean H/M ratios were significantly different among the three groups (P < 0.0001). H/M ratios of both NDPD and DPD patients groups (H/M = 1.83 +/- 0.50 and 1.24 +/- 0.40, respectively) were significantly lower than in MSA patients (H/M = 2.52 +/- 0.60). However, in NDPD patients, H/M was significantly higher than in DPD patients. When compared to MSA patients, NDPD patients showed a regional reduction in MIBG uptake in all left ventricle regions markedly in the apex and the inferior wall. Our results suggest that MIBG myocardial scintigraphy (analysis of both H/M ratio and regional MIBG uptake) may be more sensitive than standard autonomic testing for the early detection of silent autonomic dysfunction in PD.  相似文献   
7.
Mirizzi's syndrome is the name given to common bile duct obstruction secondary to a stone in the cystic duct. The cause of the biliary obstruction is often difficult to establish before operation. We report two cases of Mirizzi's syndrome, diagnosed endoscopically and treated without surgery. One of the patients was treated by drainage of both the common bile duct and the gallbladder associated with monooctanoin dissolution of the gallstone. The other was treated by common bile duct stenting.  相似文献   
8.
Summary Simultaneous tumors are rarely encountered during the course of acute leukemias. We report on a case of seminoma of the testis that occurred during the evolution of acute myelogenous leukemia. To our knowledge, this stimultaneous association has not previously been described, but a causal relationship was not apparent in the present case. The likelihood of a common carcinogenesis existed, but direct exposure to carcinogens could not be established. Although the results of a physical examination and echography were normal at the time of diagnosis, we cannot exclude the presence of microscopic cancer of the testis. Since the dissemination pattern of seminoma is usually slower than that observed in this case and the disease remains limited to the lymph nodes for long periods following dissemination, the rapid development of the present case might have been attributable to the immunosuppression and the scrotal sepsis that occurred during the induction therapy. Immunosuppression might have stimulated the progression of a primary microscopic seminoma and the development of metastasis, whereas the scrotal sepsis and inflammation might have favored the occurrence of metastasis through bypass of the lymphatic barrier.  相似文献   
9.
10.
May garlic have beneficial effects on cardiovascular and metabolic diseases?Some data support that garlic may have benefical medicinal functions on dyslipidemia, hypertension and diabetes mellitus. However the results of clinical trials are controversial. Several metaanalysis and a systematic review didn’t confirm that garlic or its compounds had significant effects on plasma lipids or on blood pressure. The hypoglycaemic effect was supported by any randomised clinical study. Contrary to the assertion of many physicians and patients, consumption of garlic can’t be considered as an alternative treatment for dyslipidemia or hypertension.  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