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   2923篇
  免费   131篇
  国内免费   17篇
耳鼻咽喉   40篇
儿科学   51篇
妇产科学   63篇
基础医学   377篇
口腔科学   123篇
临床医学   165篇
内科学   735篇
皮肤病学   234篇
神经病学   228篇
特种医学   74篇
外科学   366篇
综合类   14篇
预防医学   51篇
眼科学   17篇
药学   198篇
中国医学   19篇
肿瘤学   316篇
  2023年   12篇
  2022年   31篇
  2021年   47篇
  2020年   39篇
  2019年   44篇
  2018年   53篇
  2017年   51篇
  2016年   49篇
  2015年   57篇
  2014年   92篇
  2013年   99篇
  2012年   119篇
  2011年   163篇
  2010年   81篇
  2009年   86篇
  2008年   154篇
  2007年   191篇
  2006年   179篇
  2005年   186篇
  2004年   160篇
  2003年   165篇
  2002年   182篇
  2001年   50篇
  2000年   52篇
  1999年   72篇
  1998年   36篇
  1997年   35篇
  1996年   38篇
  1995年   38篇
  1994年   26篇
  1993年   34篇
  1992年   29篇
  1991年   35篇
  1990年   30篇
  1989年   43篇
  1988年   40篇
  1987年   26篇
  1986年   22篇
  1985年   18篇
  1984年   19篇
  1983年   14篇
  1982年   10篇
  1981年   13篇
  1980年   12篇
  1979年   10篇
  1975年   11篇
  1974年   12篇
  1972年   8篇
  1969年   8篇
  1968年   12篇
排序方式: 共有3071条查询结果,搜索用时 15 毫秒
1.
2.
In floating hip injuries, the priority of the steps in fixation has not been well described. We have treated these patients in accordance with the following protocols. In patients with pelvic ring fractures, the external fixation should be performed first, and in patients with acetabular fractures, the femoral fractures should be internally fixated first. The purpose of the present study was to review our experience with these fracture treatments to evaluate our strategy. For 8 years, 31 patients with femoral fractures associated with ipsilateral fractures: 26 unstable pelvic ring fractures and 7 unstable acetabular fractures were surgically treated at our level 1 trauma center. We reviewed the admission, operation, and follow-up records retrospectively and evaluated the order of the fixation and the complications. Two patients with acetabular fractures failed to follow our protocol outlined at the preoperative planning stage. There were no surgical difficulties other than two patients with the hemipelvis dislocated proximally who required traction of the fixated femur. The complications that were thought to be related to our protocol were one fat embolism syndrome and one pubic fracture displacement. One heterotopic ossification seemed to occur due to using a single approach for both fractures. We believe our protocol to be generally effective, however, in patients with acetabular and vertical shear type pelvic ring fractures, the internal or external fixation of the femur should be performed before the internal fixation of the pelvis.  相似文献   
3.
Intralobar pulmonary sequestration associated with asymptomatic aspergillosis is a rare case. We describe the case of a 65-year-old woman with intrapulmonary sequestration, anomalous systemic arterial supply to the left lower lobe and aspergillosis who underwent left lower lobectomy and ligation of an anomalous artery by Video-Assisted Thoracoscopic surgery (VATS). Pathological examination showed the parenchymal distortion and chronic inflammation. Aspergillus were found in the cyst. VATS lobectomy for intralobar pulmonary sequestration is a safe and valid procedure.  相似文献   
4.
5.
Background Cardiopulmonary bypass (CPB) may contribute to the complications and it is assumed that eliminating cardiopulmonary bypass has the potential of reducing post operative morbidity after coronary artery bypass grafting (CABG). The study was carried out to compare mortality and morbidity in the off-pump and on-pump CABG groups. Methods We prospectively analysed 200 patients undergoing CABG. Group A consists of 100 patients underwent multi-vessel off-pump CABG and group B consists of 100 patients underwent CABG with CPB. The incidence of complications (mortality, re-exploration for bleeding, myocardial infarction, atrial fibrillation, neurological events, new onset renal failure (s. creatinine>1.6 mg/dL) pulmonary complications, length of ICU stay and hospital stay were recorded, analysed and compared. Results OPCAB patients received 2.73±0.61 grafts/patient and on-pump CABG patients received 3.39±0.75 grafts/patient (p value<0.00001). There was no significant statistical difference in mortality, incidence of stroke between OPCAB and CABG with CPB patients. Length of ICU stay was 32.84±4.22 vs 44.85±7.18 hrs (p value<0.00001) and hospital stay was 6.52±0.69 vs 7.94±0.92 days (p value<0.00001) between group A and group B respectively. Incidence of atrial fibrillation was less in OPCAB group 7% vs 12% although it was statistically not significant (p value 0.33). It was observed in our study that there was no significant deference in worsening of existing renal failure between on-pump CABG and OPCAB 6% vs 2% (P value 0.28). Blood utilization was significantly less in OPCAB group (p value<0.001). Conclusion There was no statistically significant difference in terms of mortality, incidence of stroke and new onset renal failure in both groups. But there was lesser incidence of post operative atrial fibrillation, worsening of existing renal failure in off-pump group though statistically not significant. There was significant reduction in blood utilization, length of ICU and hospital stay in OPCAB group.  相似文献   
6.
The effect of 1α-hydroxyvitamin D3 (1α(OH)D3) on the metabolic bone disorders developed in gastrectomized rats were investigated biochemically and histomorphologically. 1α(OH)D3 was suspended in 0.2 % Triton-X-100 aqueous solution after dissolving in a very small amount of ethanol, was given orally to the rats for 10 weeks. The sham operated animals and the gastrectomy control animals received the vehicle alone. Gastrectomy was followed by the development of the metabolic bone disorders after 10 weeks of observation. This was characterized by reduction in ash content of the femur and histologically by a disappearance of the trabecular bone in tibial metaphysis. Decrease Ca absorption from the intestines was demonstrated by a radiotracer technique. Biochemical studies showed significant decreases in serum 25(OH)D concentration in gastrectomized rats. These findings suggest that gastrectomy partially impairs intestinal absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic disorders in rats. The administration of 1α(OH)D3 increased dose-dependently serum calcium and Ca absorption from the intestine and prevented the development of bone metabolic disorders histomorphologically.  相似文献   
7.
To examine whether prostacyclin has an attenuating effect on nonspecific bronchial responsiveness in asthma, we measured provocative concentration of methacholine producing a 20% fall in forced expiratory volume in 1 second (PC20-FEV1) before and after oral administration of a chemically stable prostacyclin analog (OP-41483) (200 μg 4 times a day for 4 days) in 8 patients with stable asthma. Neither baseline pulmonary function nor PC20-FEV1 significantly improved after the treatment. These results suggest that prostacyclin may have no direct effect on bronchial responsiveness in asthmatics. Further studies using more potent and long-lasting prostacyclin mimetic will be needed to confirm the conclusion.  相似文献   
8.
The nitric oxide synthase (NOS) gene is thought to be associated with essential hypertension (EH), because NO is implicated in endothelium-mediated vasodilation. We investigated the possible association between the alleles of simple tandem repeat DNA polymorphism of the endothelial constitutive NOS (cNOS) gene and EH in Japanese subjects. In all, 100 patients with EH and 123 subjects with normal blood pressure were studied. Polymerase chain reaction was used to amplify the CA repeat site in the endothelial cNOS gene and alleles based on the CA repeat number were determined. The allele frequencies in the hypertensive group and normotensive group were then compared. Twenty-three alleles were identified in this study of Japanese subjects. The overall distributions of allele frequencies in the two groups were not significantly different. However, comparing the allele frequencies in the EH group without left ventricular hypertrophy (LVH) and the normotensive group, the overall distributions were significantly different (p = 0.019). The 33-repeat allele was found more frequently in the EH group without LVH than in the normotensive group (p = 0.000047, Odds ratio = 3.71). In conclusion, the 33-repeat allele of the endothelial cNOS gene is associated with EH without LVH, and may be a genetic marker of EH in Japanese subjects.  相似文献   
9.
Antithrombin III (AT III) is known to be the most important inhibitor of serine protease in the coagulation system. In the presence of heparin, AT III is converted from its progressive activity state to an immediate activity state. In disseminated intravascular coagulation (DIC) in the field of obstetrics, the treatment has to be initiated very early. Heparin treatment, on the other hand, is critical since frequently postpartal or postoperative wound bleeding is present. We, therefore, established diagnostic criteria for the early diagnosis of DIC and investigated the clinical efficacy of a therapy with AT III in a well-controlled comparative study versus the injectable synthetic protease inhibitor FOY. The results of the trial showed that the AT III group (92%; n = 24) was significantly (p less than 0.001) superior in clinical efficacy to the FOY group (60%; n = 15). No side effects whatsoever were observed after treatment with AT III concentrate (Behring Institute). From these results, it could be concluded that a single therapy with AT III concentrate can sufficiently control the symptoms of DIC in the field of obstetrics without the risk of increased bleeding.  相似文献   
10.
OBJECTIVE: This article reports a case of bilateral cleft lip and alveolus (BCLA) for which excessive rapid palatal expansion with a Latham appliance was performed for preoperative alignment of the protruded premaxilla. Postoperative changes of maxillary width were investigated with serial plaster casts. PATIENT AND RESULTS: A 3-month-old girl presented with complete BCLA in which the premaxilla was markedly protruded. Preoperative alignment of the protruded premaxilla with a Latham appliance was planned to facilitate primary lip repair. The appliance was placed when the patient was 4.5 months old. The necessary palatal expansion was estimated to be 7.0 mm in order to move the premaxilla backward into the ideal position. After palatal expansion and posterior repositioning of the protruded premaxilla, the primary operation, including cheiloplasty and gingivoperiosteoplasty, was performed when the patient was 7 months old. Excessive maxillary expansion might be a cause of transverse maxillomandibular discrepancy. Measurement with serial plaster casts demonstrated that maxillary widths increased from 42.3 mm pretreatment to 49.0 mm after orthopedic treatment but relapsed markedly to 43.5 mm at 3 months after the primary operation. Therefore, the net change of maxillary widths was only 1.2 mm. After alignment of the protruded premaxilla, tension-free soft tissue repairs were performed, and a harmonious alveolar arch was obtained without change in maxillary width. CONCLUSION: These results indicate that this method is useful for preoperative management of BCLA with protruded premaxilla.  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