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   224篇
  免费   11篇
耳鼻咽喉   1篇
儿科学   4篇
妇产科学   9篇
基础医学   51篇
口腔科学   5篇
临床医学   6篇
内科学   33篇
皮肤病学   11篇
神经病学   1篇
特种医学   6篇
外国民族医学   1篇
外科学   47篇
综合类   5篇
预防医学   19篇
眼科学   2篇
药学   24篇
中国医学   1篇
肿瘤学   9篇
  2023年   2篇
  2022年   3篇
  2021年   10篇
  2020年   6篇
  2019年   5篇
  2018年   8篇
  2017年   5篇
  2016年   8篇
  2015年   11篇
  2014年   9篇
  2013年   16篇
  2012年   24篇
  2011年   19篇
  2010年   4篇
  2009年   7篇
  2008年   12篇
  2007年   18篇
  2006年   6篇
  2005年   1篇
  2004年   7篇
  2003年   2篇
  2002年   3篇
  2001年   6篇
  2000年   3篇
  1999年   2篇
  1998年   1篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
  1973年   2篇
  1972年   2篇
  1971年   1篇
  1970年   2篇
  1969年   2篇
  1968年   1篇
  1967年   1篇
  1966年   3篇
  1965年   2篇
排序方式: 共有235条查询结果,搜索用时 31 毫秒
31.
32.
The present study was designed to investigate the potential protective effect of melatonin against the renal toxicity of fumonisin in female rats. Six groups of animals were used in this study. The first group served as control. The second group was given melatonin only at a dose level of 10 mg/kg. The third group was fed ration contaminated with fumonisin (100 mg/kg diet). The fourth group was fed ration contaminated with fumonisin (200 mg/kg diet). The fifth group was given daily interperitoneal injection (IP) 10 mg/kg melatonin and fed ration contaminated with fumonisin (100 mg/kg diet). The sixth group was given daily interperitoneal injection of 10 mg/kg melatonin and fed ration contaminated with fumonisin (200 mg/kg diet). The rats were treated for 1 month. Histopathological and histochemical changes in the kidney were investigated. In addition, DNA ploidy was measured in the kidney. Fumonisin administration (100 or 200 mg/Kg diet) to unpretreated control rats caused extensive renal damage as evaluated by histopathology, histochemistry, and/or DNA ploidy measurement. No apparent changes following administration of melatonin. Melatonin coadministration to the fumonisin-administered rats reduced kidney damage and the tissues appeared more or less like the normal. The present study indicates that melatonin has a protective effect in fumonisin-induced renal damage.  相似文献   
33.
34.
35.
Treatment of benign bone tumours using external fixation   总被引:1,自引:0,他引:1  
We present a retrospective study of patients suffering from a variety of benign tumours in whom external fixators were used to treat deformity and limb-length discrepancy, and for the reconstruction of bone defects. A total of 43 limbs in 31 patients (12 male and 19 female) with a mean age of 14 years (2 to 54) were treated. The diagnosis was Ollier's disease in 12 limbs, fibrous dysplasia in 11, osteochondroma in eight, giant cell tumour in five, osteofibrous dysplasia in five and non-ossifying fibroma in two. The lesions were treated in the tibia in 19 limbs, in the femur in 16, and in the forearm in eight. The Ilizarov frame was used in 25 limbs, the Taylor Spatial Frame in seven, the Orthofix fixator in six, the Monotube in four and the Heidelberg fixator in one. The mean follow-up was 72 months (22 to 221). The mean external fixation period was 168 days (71 to 352). The mean external fixation index was 42 days/cm (22.2 to 102.0) in the 22 patients who required limb lengthening. The mean correction angle for those with angular deformity was 23 degrees (7 degrees to 45 degrees ). At final follow-up all patients had returned to normal activities. Four patients required a second operation for recurrent deformity of further limb lengthening. Local recurrence occurred in one patient, requiring further surgery.  相似文献   
36.

Background

Plantar ulcers pose a frequent serious complication in the neuropathic foot. Previous studies suggested that ulcer initiation occurs within the plantar soft tissue rather than on the plantar surface. This study investigated the effectiveness of different shaped silicone insoles on the reduction of both plantar soft tissue strain and pressure. The authors have found no previous experimental studies on the effectiveness of insole shape on reducing plantar soft tissue strain during standing.

Methods

A custom molded silicone insole which allowed passage of ultrasound to the plantar surface of the foot was prototyped for this study. Soft tissue strain was computed from soft tissue thickness measured using ultrasound in five conditions: unloaded, barefoot, wearing a prefabricated silicone insole, wearing the custom molded silicone insole alone then with a metatarsal pad. Plantar pressure was measured for the same conditions.

Findings

The custom molded insole was found to significantly reduce soft tissue strain and plantar pressure relative to both the barefoot condition and the prefabricated insole under the second and third metatarsal heads. The metatarsal pad was found to significantly reduce soft tissue strain but not significantly affect plantar pressure.

Interpretation

A custom molded silicone insole can effectively reduce both soft tissue strain and plantar pressure and is thus preferable to a prefabricated insole. It is suggested that quantifying the reduction of soft tissue strain is an essential design requirement for orthotic insoles since plantar pressure may not be a sufficient indicator of the effectiveness of an insole in preventing ulcer initiation.  相似文献   
37.
One hundred three out of 225 (45.8%) of the Red Sea fish Saurida tumbil were infected with microsporidian parasites. The infection was recorded as tumor-like masses (whitish macroscopic cysts) or xenomas often up to 2 cm in diameter and embedded in the peritoneal cavity. Generally, the infection was increased during winter 63.8% (86 out of 135) and fall to 18.9% (17 out of 90) in summer. Light microscopic study revealed that xenomas were encapsulated by a fibrous layer encircling numerous sporophorous vesicles filled with mature spores measuring 1.7 ± 0.6 (1.5–2.7 μm) × 1.5 ± 0.3 μm (1.2–1.8 μm) in size. Ultrastructural microscopic study showed the presence of smooth membranes of the sarcoplasmic reticulum forming a thick, amorphous coat surrounding various developmental stages of the parasite. The various recognizable stages of the parasite were uninuclear, binucleated, and multinucleated meronts followed by detachment of the plasmalemma of the sporont from the sporophorous vesicle producing sporoblasts. Mature spores consist of a spore coat and spore contents. The spore contents consist of the uninucleated sporoplasm and a posterior vacuole located at the posterior end. The polar tube consists of a straight shaft and a coiled region (26–32 coils) arranged in many rows along the inside periphery of the spore. The polaroplast consisted of an anterior region of closely and loosely packed membranes. Molecular analysis based on the small subunit rDNA gene was performed to determine the phylogenetic position of the present species. The percentage identity between this species and a range of other microsporidia predominantly from aquatic hosts demonstrated a high degree of similarity (>92%) with eight Pleistophora species. Comparison of the nucleotide sequences and divergence showed that the sequence of the present microsporidium was most similar to that of Pleistophora anguillarum (99.8% identity) differing in 13 nucleotide positions. So, the present species was recorded and phylogenetically positioned as a new species of Pleistophora.  相似文献   
38.
Angiotensin converting enzyme (ACE) gene polymorphism was previously studied in some cardiovascular diseases. There are only few studies which investigated this polymorphism in patients with rheumatic heart disease (RHD). The results of these investigations are inconsistent. Furthermore, gene polymorphism distribution is different in various ethnic populations. We conducted this study to demonstrate this gene polymorphism in Egyptian children with RHD. Leukocytes DNA was extracted from 139 patients with RHD and 79 healthy control children. After amplification by the PCR, the products were separated by electrophoresis in 6% polyacrylamide gel and visualized after ethidium bromide staining with UV light. The PCR product is a 190-bp fragment in the absence of the insertion (D allele) and a 490-bp fragment in the presence of the insertion (I allele). Gene polymorphism was as follows: DD gene when lane contains only 190-bp fragment, II gene when lane contains only 490-bp fragment and ID gene when lane contains both fragments. We found that gene polymorphism in both control and patients groups followed the following order of distribution from highest to lowest: ID, II, DD gene. The frequency in control group was 49.4, 36.7, and 13.9%, respectively. In patients groups, the gene frequency was 42.5, 30.9, and 26.6%, respectively. DD gene frequency differs significantly between the two groups. We concluded that patients with RHD have a higher ACE-DD genotype than normal control. ACE-DD genotype may be a risk factor for RHD in Egyptian children.  相似文献   
39.
40.
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