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   2366篇
  免费   101篇
  国内免费   11篇
耳鼻咽喉   130篇
儿科学   94篇
妇产科学   101篇
基础医学   125篇
口腔科学   158篇
临床医学   235篇
内科学   473篇
皮肤病学   48篇
神经病学   120篇
特种医学   95篇
外科学   537篇
综合类   47篇
一般理论   1篇
预防医学   95篇
眼科学   64篇
药学   79篇
中国医学   2篇
肿瘤学   74篇
  2024年   2篇
  2023年   11篇
  2022年   9篇
  2021年   44篇
  2020年   30篇
  2019年   43篇
  2018年   63篇
  2017年   42篇
  2016年   58篇
  2015年   61篇
  2014年   67篇
  2013年   108篇
  2012年   153篇
  2011年   176篇
  2010年   85篇
  2009年   76篇
  2008年   215篇
  2007年   213篇
  2006年   254篇
  2005年   182篇
  2004年   131篇
  2003年   133篇
  2002年   104篇
  2001年   48篇
  2000年   43篇
  1999年   36篇
  1998年   8篇
  1997年   8篇
  1996年   8篇
  1995年   8篇
  1994年   3篇
  1993年   2篇
  1992年   14篇
  1991年   12篇
  1990年   13篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1984年   1篇
  1982年   2篇
  1977年   2篇
  1969年   1篇
  1966年   1篇
排序方式: 共有2478条查询结果,搜索用时 328 毫秒
1.
Ameloblastic carcinoma (AC) is an aggressive malignant epithelial odontogenic tumor. It may appear de novo or originate from a pre-existing ameloblastoma or odontogenic cyst. To our knowledge, an AC that originates from the anterior skull base has not been reported before in the English literature. We report a case of an AC that originated from the anterior skull base and invaded the dura of the anterior fossa and discuss its clinical course and treatment.  相似文献   
2.
3.
After the chondrogenic potential of free grafts of perichondrium was shown in several experimental studies, perichondrium has been used to reconstruct cartilage tissue in various clinical situations. This study investigates the effects of human amniotic fluid on neochondrogenesis from free perichondrial grafts in a rabbit model. Since this fluid contains high concentrations of hyaluronic acid, hyaluronic acid-stimulating activator, growth factors, and extracellular matrix precursors during the second trimester, it may have a stimulating effect on neochondrogenesis. Perichondrial grafts, measuring 20 x 20 mm2 were obtained from the ears of 144 New Zealand young rabbits and were sutured over the paravertebral muscles. The rabbits were randomly divided into three groups with 48 rabbits per group. In group 1, 0.3 ml human amniotic fluid, and in group 2, 0.3 ml saline were injected underneath the perichondrial grafts. Group 3 formed the control group in which no treatment was given. Histologically, neochondrogenesis was evaluated in terms of cellular form and graft thickness at 2, 4, 6, and 8 weeks after surgery. In group 1, the mature cartilage was generated quickly and the cartilage plate in this group was significantly thick and extensive when compared with groups 2 and 3 at 8 weeks ( p<0.05 ANOVA). In conclusion, our study shows that human amniotic fluid enhances neochondrogenesis from free perichondrial grafts. The rich content of hyaluronic acid and growth factors possibly participate in this result.  相似文献   
4.
Purpose: to determine wheather an association exists between sensorineural hearing loss and pseudoexfoliation. Methods: Hearing thresholds were determined by using pure-tone au-diometry in 75 patients with pseudoexfoliation syndrome and in the control group of 75 subjects without pseudoexfoliation The groups were sex and age matched. Results: The frequency of  相似文献   
5.
OBJECTIVE: To evaluate the efficacy of diazepam and atropine sulfate premedication in preventing nausea and vomiting after strabismus surgery under general anesthesia. METHODS: Fifty children age 4 to 15 years who underwent strabismus surgery at Cukurova University Medical Faculty, Department of Ophthalmology, from February 2000 to June 2000 were randomized into 2 groups: 25 children in the control group did not receive premedication, whereas 25 children in the treatment group received premedication with 0.15 mg/kg diazepam and 0.015 mg/kg atropine sulfate. Occurrence of postoperative nausea and vomiting (PONV) was recorded. RESULTS: The incidence of PONV was lower in the premedicated group (P <.018, chi(2) test). CONCLUSIONS: It is concluded that diazepam and atropine sulfate premedication decreases nausea and vomiting after strabismus surgery.  相似文献   
6.
BACKGROUND: Mycobacteria are being investigated for modulation of inflammation in asthma and atopic disorders by eliciting particularly strong protective TH1 immune responses. OBJECTIVE: To investigate the long-term effects of intratracheally administered Mycobacterium vaccae on an experimental murine model of asthma. METHODS: BALB/c mice were placed in 4 groups: long-term M. vaccae, M. vaccae, asthma, and control groups. All groups but controls were sensitized intraperitoneally and challenged intratracheally with ovalbumin. The long-term M. vaccae and M. vaccae groups were treated with M. vaccae intratracheally simultaneously during challenges. Finally, mice in the long-term M. vaccae group were rechallenged with ovalbumin nebulization 24 days later. Evaluations of lung histopathologic findings and serum cytokine levels were performed. RESULTS: Comparison of the long-term M. vaccae group with the asthma model group revealed that the number of hyperplasic goblet cells in small and large airways (small airway: P < .05; large airways: P < .01) and thickness of basement membrane in large airways were significantly less in the long-term M. vaccae group. Furthermore, numbers of hyperplasic goblet cells in small airways (P < .05) and basement membrane in the large airway (P < .05), as well as inflammation in small airways (P < .01), were significantly less in the M. vaccae group when compared with the asthma model group. Interferon-gamma secretion from splenocytes of the M. vaccae group was significantly higher than the asthma model and long-term M. vaccae groups. CONCLUSION: Intratracheal administration of M. vaccae exerted a long-lasting ameliorating effect on airway histopathologic features of a murine asthma model.  相似文献   
7.
A survey study was conducted to investigate the possible effects of mobile phone on headache, dizziness, extreme irritation, shaking in the hands, speaking falteringly, forgetfulness, neuro-psychological discomfort, increase in the carelessness, decrease of the reflex and clicking sound in the ears. There is no effect on dizziness, shaking in hands, speaking falteringly and neuro-psychological discomfort, but some statistical evidences are found that mobile phone may cause headache, extreme irritation, increase in the carelessness, forgetfulness, decrease of the reflex and clicking sound in the ears.  相似文献   
8.
Because slime-forming microorganisms are the major causative agents of graft infections, we aimed to investigate bacterial adherence in slime-forming and nonslime-forming Staphylococcus aureus and to determine the role of neuraminidase (NANase) on adherence to gelatin-impregnated polyester fiber graft fabric. An in vitro model was developed to quantitatively measure bacterial adherence to the surface of the graft. The grafts were divided into two groups – those colonized with slime-forming S. aureus and those colonized with nonslime-forming S. aureus. The grafts were put into sterile tubes and human plasma was instilled and incubated at 37°C to perform fibrin deposition on the grafts. After 48 h of incubation, grafts were drained and inoculated with slime-forming or nonslime-forming S. aureus in triptic soy broth in the presence or absence of NANase. Following 36 h of incubation at 36°C, grafts were vortexed and cultured to perform a colony count. Bacterial counts were expressed as total colony-forming units per square centimeter of graft. Slime-forming S. aureus had greater affinity with the graft compared with nonslime-forming S. aureus (P < 0.05). The adherence of slime-forming S. aureus was impaired by NANase treatment (P < 0.001) but NANase treatment of nonslime-forming S. aureus did not change the adherence to the graft (P > 0.05). These results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming S. aureus can be decreased by NANase treatment. This may have implications for the development of neuraminidase-embedded vascular grafts to diminish biomaterial-related infections.  相似文献   
9.
BACKGROUND: The aim of this study was to evaluate the effects of metformin and acarbose on insulin resistance, hormone profiles and ovulation rates in patients with clomiphene citrate-resistant polycystic ovary syndrome (PCOS). METHODS: Thirty clomiphene citrate-resistant patients were selected randomly and divided into two groups. Group I was treated with 100 mg/day clomiphene citrate and 300 mg/day acarbose 100 mg/day orally, for 3 months. Group II was treated with clomiphene citrate 100 mg/day and metformin 1700 mg/day orally, for 3 months. Serum fasting insulin and glucose, FSH, LH, estradiol, progesterone, prolactin and total testosterone levels plus body mass index (BMI) were measured before and after treatment. Follicle growth was followed by transvaginal ultrasonography. RESULTS: LH:FSH ratio and total testosterone concentrations decreased (P<0.05) and ovulation rates increased in both groups. Reduction in weight and BMI was only significant in the acarbose group. CONCLUSIONS: Both treatment modalities were effective in the treatment of insulin resistance and improving ovulation rates. Increase in the number of eumenorrhoeic and normoinsulinaemic cases and decrease in the number of insulin-resistant cases were significant in both groups (P<0.05). Ovulation rate was greater in the metformin group in the second month of therapy (P<0.05). Acarbose was found to be a safe and effective agent that could be used in cases with clomiphene-resistant PCOS.  相似文献   
10.
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