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   2281篇
  免费   136篇
  国内免费   2篇
耳鼻咽喉   63篇
儿科学   107篇
妇产科学   42篇
基础医学   195篇
口腔科学   20篇
临床医学   154篇
内科学   570篇
皮肤病学   31篇
神经病学   142篇
特种医学   68篇
外科学   413篇
综合类   25篇
预防医学   88篇
眼科学   112篇
药学   129篇
中国医学   2篇
肿瘤学   258篇
  2023年   17篇
  2022年   35篇
  2021年   105篇
  2020年   46篇
  2019年   88篇
  2018年   101篇
  2017年   50篇
  2016年   62篇
  2015年   69篇
  2014年   112篇
  2013年   124篇
  2012年   182篇
  2011年   163篇
  2010年   80篇
  2009年   85篇
  2008年   151篇
  2007年   130篇
  2006年   106篇
  2005年   98篇
  2004年   80篇
  2003年   63篇
  2002年   50篇
  2001年   38篇
  2000年   37篇
  1999年   42篇
  1998年   9篇
  1997年   7篇
  1996年   12篇
  1995年   9篇
  1994年   11篇
  1993年   6篇
  1992年   31篇
  1991年   24篇
  1990年   21篇
  1989年   22篇
  1988年   27篇
  1987年   22篇
  1986年   11篇
  1985年   14篇
  1984年   6篇
  1983年   5篇
  1979年   4篇
  1978年   5篇
  1976年   5篇
  1974年   6篇
  1973年   6篇
  1972年   6篇
  1970年   7篇
  1968年   5篇
  1961年   3篇
排序方式: 共有2419条查询结果,搜索用时 763 毫秒
991.
PRECIS: A 12-year-old female presented with symptoms and signs of orbital apex syndrome (OAS), secondary to stage IV alveolar rhabdomyosarcoma (RMS) originating in the sphenoid and ethmoid sinuses. OBJECTIVE: To present a case of alveolar rhabdomyosarcoma, unusual in its presentation as orbital apex syndrome and also its origin from the sphenoid and ethmoid sinuses. DESIGN:: Observational case report. METHODS: Ophthalmologic findings, neuroimaging, medical and surgical intervention, histopathologic analysis, and clinical course are described. RESULTS: A 12-year-old female presented with progressive visual loss in her left eye, difficulty with eye movements, and mild headache. Her examination was consistent with orbital apex syndrome. Imaging with contrast revealed a mass originating in the left sphenoid and ethmoid sinuses invading the left optic canal. Emergent biopsy was interpreted as alveolar rhabdomyosarcoma; subsequent metastatic work-up revealed bone marrow metastases. The patient was diagnosed with stage IV alveolar rhabdomyosarcoma and immediately started on combination orbital radiation therapy (RT) and systemic chemotherapy. She experienced gradual improvement of ocular motility, though her optic neuropathy persisted. CONCLUSION: Alveolar rhabdomyosarcoma of paranasal origin, specifically from the sphenoid and ethmoid sinuses, should be included in the differential diagnosis for orbital apex syndrome in children.  相似文献   
992.
The serum enzyme values (GOT, GPT, LDH and Aldolase) of 13 fit healthy volunteers were determined before and after physical effort of a moderate grade of 3.9 Kcal/min. The pulse rate pattern of the subjects during the exercise of climbing up and down a staircase for 30 minutes and during a 10 minute recovery phase was also recorded. The pulse pattern was in no case in excess of 150 bpm and full recovery was achieved within 10 minutes indicating that the exercise was moderate. The serum enzyme values after the exercise were raised. The difference between the exercise and rest values of the four enzyme activities were significant at the 1% level. It was observed that the raised enzyme activity level dropped to normal levels within 24 hours after the exercise. Large individual variations in the rise of these enzyme levels after exercise were observed and hence it is difficult to quantitate the phenomenon. Consequently the value of serum enzyme levels after the exercise as a practical-index of physiological strain is limited.  相似文献   
993.
The use of organochlorine insecticides for public health programs is indisputably necessary in developing countries. Thus, there is a need to evaluate human response to these chemicals under local field conditions. The effects of a short-term, 16-wk exposure to hexachlorocyclohexane has been evaluated and compared in malaria spraymen with and without any previous occupational exposure to this insecticide by measuring the pre- and post-exposure serum hexachlorocyclohexane concentration. A significant increase in original serum hexachlorocyclohexane concentration. A significant increase in original serum hexachlorocyclohexane concentration was observed in subjects on their first occupational exposure (5X), compared to those with previous exposure (3X). All workers reached approximately the same serum levels within 16 wk, regardless of their history of previous exposure.  相似文献   
994.
995.
Increasing number of transplants worldwide has resulted in an increase in the incidence of fungal infections. Prolonged neutropenia, immunosuppression and graft vs. host disease all result in high predisposition to fungal infections. The likelihood of developing a fungal infection increases with the severity and duration of neutropenia, which, in the case of cancer or chemotherapy for the treatment of hematological malignancies, can range from a few days to several weeks. Invasive fungal infections are difficult to diagnose and neutropenic patients with fever often receive empirical antifungal therapy. This provides a rationale for the prophylactic use of antifungal agents. The empirical use of liposomal amphotericin B has overcome some of the difficulties usually found in this setting. The majority of clinical efficacy data related to liposomal amphotericin B are derived from compassionate use studies and case series. The major advantage of these liposomal formulations of amphotericin B is a reduction in amphotercin toxicity. Use of liposomal amphotericin has been shown to be a cost-effective approach abroad and the same has been our experience also. Commercially ambisome and Fungisome are the only products that contain true liposomes. Unlike ambisome, which needs to be used in dose of 3 mg/kg/day Fungisome is effective in the dose of 1-3 mg/kg bodyweight. The Indian liposomal preparation has shown to be safe and effective used in over 150 transplant patients in our experience. We conclude that the liposomal amphotericin is better-tolerated and also gives,better responses in documented fungal infections.  相似文献   
996.
The non-immune, non-spherocytic anemias result from multiple potential etiologies. We report a 16-year-old girl, who was presented with a long-standing anemia and normal blood screening tests except an elevated hemoglobin F. Her diagnosis of unstable hemoglobinopathy was made only after gene sequencing of the beta-globin chain.  相似文献   
997.
998.
BACKGROUND: The consequences of repeated exposure to psychostimulants have been hypothesized to model aspects of schizophrenia. This experiment assessed the consequences of the administration of an escalating dosing regimen of amphetamine (AMPH) on attentional performance. Fos-like immunoreactivity (Fos-IR) in selected regions of these rats' brains was examined to test the hypothesis that AMPH-sensitized attentional impairments are associated with increased recruitment of basal forebrain cholinergic neurons. METHODS: Rats were trained in a sustained attention task and then treated with saline or in accordance with an escalating dosing regimen of AMPH (1-10 mg/kg). Performance was assessed during the pretreatment and withdrawal periods and following the subsequent administration of AMPH "challenges" (.5, 1.0 mg/kg). Brain sections were double-immunostained to visualize Fos-IR and cholinergic neurons. RESULTS: Compared with the acute effects of AMPH, AMPH "challenges," administered over 2 months after the pretreatment was initiated, resulted in significant impairments in attentional performance. In AMPH-pretreated and -challenged animals, an increased number of Fos-IR neurons was observed in the basal forebrain. The majority of these neurons were cholinergic. CONCLUSIONS: The evidence supports the hypothesis that abnormally regulated cortical cholinergic inputs represent an integral component of neuronal models of the attentional dysfunctions of schizophrenia.  相似文献   
999.
Joint reconstruction for pelvic discontinuity because of massive acetabular insufficiency presents a significant surgical challenge. Using retrograde-inserted Steinmann pins to rebuild the dome may be associated with early implant failure because of insufficient mechanical stability and neurovascular injury resulting from pin misplacement. Retrograde pins cannot be placed completely across the pelvic defect. We hypothesized that large Steinmann pins placed anterograde under direct vision from the iliac crest completely across the acetabular column and floor defects would minimize the risk of early failure, and could be placed safely without the use of fluoroscopy in combination with a posterior hip approach. The purpose of our study was to review the mechanical failure and complication rates of nine patients (10 hips) treated between 1996 and 2002 for pelvic discontinuity using this pin placement technique to reinforce a cemented roof ring hip reconstruction done via a posterior approach. None of the patients had implant loosening or failure, there were no neurovascular complications, and no perioperative deaths. One patient required cup revision for recurrent dislocation. All patients were bedridden or wheelchair-bound before surgery, but regained independent household walking by 6 weeks postoperatively. Reinforcing the acetabulum with a lattice girder of anterograde pins provides safe and effective hip reconstruction.  相似文献   
1000.
PURPOSE OF REVIEW: A variation in the gene encoding the cysteine protease calpain 10 (CAPN10) was recently linked and associated with type 2 diabetes by positional cloning. This positional cloning was a follow-up investigation to the identification of a diabetes-linked region on human chromosome 2 identified by genome-wide scanning a few years earlier. In this paper we give a general background on the genetic studies performed on CAPN10 to date, and review the most recent studies on the functional role of calpain 10. RECENT FINDING: A haplotype or haplotype combination comprising three intronic single nucleotide polymorphisms (UCSNP-43, 19, and 63) were associated with a threefold increased risk of type 2 diabetes in the population in which linkage was first found. Another polymorphism, UCSNP-44, which is in linkage disequilibrium with a coding single-nucleotide polymorphism (Thr504Ala), has subsequently been associated with type 2 diabetes in extensive meta-analyses. Meanwhile, initial studies probing the possible role of calpain-10, completely unknown at the time, are now being pursued, both in isolated cells and humans. SUMMARY: The positional cloning of CAPN10 as a candidate gene for type 2 diabetes has been particularly fruitful. Not only has it identified an important and surprising piece of the puzzle underlying the development of diabetes, but it has also modelled and paved the way for investigations concerning complex genetic diseases other than type 2 diabetes.  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