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   842篇
  免费   66篇
耳鼻咽喉   2篇
儿科学   25篇
妇产科学   47篇
基础医学   123篇
口腔科学   6篇
临床医学   112篇
内科学   158篇
皮肤病学   16篇
神经病学   85篇
特种医学   25篇
外科学   80篇
综合类   7篇
预防医学   86篇
眼科学   9篇
药学   57篇
中国医学   1篇
肿瘤学   69篇
  2024年   2篇
  2023年   11篇
  2022年   34篇
  2021年   30篇
  2020年   25篇
  2019年   26篇
  2018年   26篇
  2017年   23篇
  2016年   25篇
  2015年   20篇
  2014年   41篇
  2013年   56篇
  2012年   60篇
  2011年   73篇
  2010年   39篇
  2009年   39篇
  2008年   42篇
  2007年   59篇
  2006年   52篇
  2005年   41篇
  2004年   50篇
  2003年   38篇
  2002年   40篇
  2001年   4篇
  2000年   2篇
  1999年   6篇
  1998年   4篇
  1997年   10篇
  1996年   3篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   6篇
  1989年   3篇
  1988年   1篇
  1982年   1篇
  1979年   1篇
  1976年   5篇
  1975年   1篇
  1973年   1篇
排序方式: 共有908条查询结果,搜索用时 24 毫秒
41.
Partial Epilepsy of Long Duration: Changing Semiology with Age   总被引:4,自引:4,他引:0  
There are few data on changing patterns of localization-related epileptic syndromes with time and particularly on changes in seizure semiology as patients age. We retrospectively reviewed 53 patients aged >60 years who had had partial epileptic seizures for a mean duration of 44 years. In 20 patients, seizures became progressively less elaborate and briefer with time. In 29 patients, seizures were unchanged. In four patients, seizures worsened, with the appearance of drop attacks, secondarily generalized seizures, increasing drug resistance, and mental deterioration. These latter 4 patients had cerebrovascular disease with multiple strokes.  相似文献   
42.
Iron-biofortified rice improves the iron stores of nonanemic Filipino women   总被引:3,自引:0,他引:3  
Iron deficiency is endemic in much of the world, and food system-based approaches to eradication may be viable with new plant breeding approaches to increase the micronutrient content in staple crops. It is thought that conventional plant breeding approaches provide varieties of rice that have 400-500% higher iron contents than varieties commonly consumed in much of Asia. The efficacy of consuming high-iron rice was tested during a 9-mo feeding trial with a double-blind dietary intervention in 192 religious sisters living in 10 convents around metro Manila, the Philippines. Subjects were randomly assigned to consume either high-iron rice (3.21 mg/kg Fe) or a local variety of control rice (0.57 mg/kg Fe), and daily food consumption was monitored. The high-iron rice contributed 1.79 mg Fe/d to the diet in contrast to 0.37 mg Fe/d from the control rice. The 17% difference in total dietary iron consumption compared with controls (10.16 +/- 1.06 vs. 8.44 +/- 1.82 mg/d) resulted in a modest increase in serum ferritin (P = 0.10) and total body iron (P = 0.06) and no increase in hemoglobin (P = 0.59). However, the response was greater in nonanemic subjects for ferritin (P = 0.02) and body iron (P = 0.05), representing a 20% increase after controlling for baseline values and daily rice consumption. The greatest improvements in iron status were seen in those nonanemic women who had the lowest baseline iron status and in those who consumed the most iron from rice. Consumption of biofortified rice, without any other changes in diet, is efficacious in improving iron stores of women with iron-poor diets in the developing world.  相似文献   
43.
44.
Uterine exteriorization during fetal surgery permits hysterotomy away from anterior placental implantations. We employed this technique in two cesarean deliveries for anterior placenta previa-accreta, facilitating selective uterine incisions. Exteriorization of the near-term gravid uterus may be a useful adjunct to cesarean delivery for anterior placenta previa-accreta.  相似文献   
45.
STUDY OBJECTIVES: To explore newly-identified respiratory cycle-related electroencephalographic changes (RCREC), which may represent microarousals, as correlates of neurobehavioral outcomes in children with sleep-disordered breathing (SDB). DESIGN: Retrospective. SETTING: University sleep laboratory. PARTICIPANTS: Ten research subjects, aged 6 to 10 years, with and without SDB. INTERVENTION: Polysomnography, Multiple Sleep Latency Tests, and tests of auditory attention before and after clinically-indicated tonsillectomy (n = 9) or hernia repair (n = 1, control). MEASUREMENTS: For the first 3 hours of nocturnal sleep, a computer algorithm quantified the degree to which delta, theta, and alpha electroencephalographic power varied within non-apneic respiratory cycles. Correlations between the RCREC and standard objective measures of SDB, sleepiness, and attention were explored. RESULTS: Five children had SDB (> 1 obstructive apnea per hour of sleep). Preoperative delta, theta, or alpha RCREC were statistically significant (P < .01) in all subjects except 1 without SDB and the 1 control. Theta RCREC correlated with rates of apneas and hypopneas (P = .01) and decreased after the apnea was treated. Postoperative changes in delta and theta RCREC predicted changes in Multiple Sleep Latency Test scores (rho = -0.84, P = .002; rho = -0.64, P = .05), whereas changes in rates of apneas and hypopneas did not (rho = -0.24, P = .50). Postoperative changes in attention tended to correlate with changes in delta RCREC (rho = -0.54, P = .11) more strongly than with changes in rates of apneic events (rho = -0.07, P = .84). CONCLUSIONS: The RCREC may reflect brief but numerous microarousals that could help to explain neurobehavioral consequences of SDB.  相似文献   
46.
47.
PURPOSE: The purpose of this prospective study was to evaluate sonographically the timing of membrane fusion and to determine its possible effect on the timing of amniocentesis. METHODS: Between May 18, 1998, and January 31, 2002, the status of amnion fusion in pregnant patients at 9-15 weeks' menstrual age was identified in women who were to undergo obstetric sonography. Amniocentesis was performed if even a small area of fused membranes that could be traversed was identified; if the membranes were completely unfused, amniocentesis was delayed. The effect of membrane fusion in terms of the need to reschedule amniocentesis was evaluated. RESULTS: We examined a total of 594 patients. Membrane fusion occurred progressively with increasing menstrual age. One hundred six early amniocenteses were scheduled, and 70 were performed; the others were delayed because the membranes were unfused. Our requirement that an area of membrane fusion be found before we would perform amniocentesis resulted in rescheduling the procedure 24-38% of the time. CONCLUSIONS: Membrane fusion, as seen sonographically, is a function of menstrual age. Even by 15 weeks, a portion of the amnion may be unfused with the chorion. Amniocenteses scheduled for early in the pregnancy may need to be delayed until later, when the membranes are at least partially fused, allowing safe passage of a needle. Delaying the procedure may incur higher expense but may be important in terms of lessening the risk involved.  相似文献   
48.
BACKGROUND: Radical changes are taking place in health care services and might be expected to cause job dissatisfaction, absenteeism, somatic complaints and mental health problems. Research in this area is limited and focused primarily on nurses. AIM: To understand the impact of the work environment on the emotional health of doctors and nurses in a general hospital setting. METHODS: Cross-sectional study using self-reported questionnaires including the General Health Questionnaire, the Posttraumatic Stress Disorder (PTSD) Checklist for Civilians, the Trauma Experiences and Work Environment Scale. RESULTS: The response rates for the study were 28% (60) for doctors and 54% (431) for nurses. Whilst the prevalences of psychiatric disorder, anxiety, depression and PTSD were higher for doctors compared with nurses, this was not statistically significant. Both groups reported witnessing someone badly injured or killed as their most distressing experience (doctors 46% versus nurses 41%). Using multiple logistic regression, significant predictors of emotional health was task orientation for doctors (OR = 1.96, 95% CI = 1.1-3.6), and PTSD (OR = 17.2, 95% CI = 6.0-49.6), work pressure (OR = 1.2, 95% CI = 1.01-1.4) and innovation (OR = 0.81, 95% CI = 0.70-0.94) for nurses. CONCLUSION: The prevalence of psychiatric disorder among the doctors and nurses was similar to that in Britain. Elements of the work environment did impact on the emotional health of health care workers. Organizational development initiatives should include employee mental health issues in order to create a more positive work environment.  相似文献   
49.
PURPOSE: To perform a pilot study of laser trabecular sclerosis (LTS) for chronic ocular hypotony after vitreoretinal surgery. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Three patients with chronic hypotony after vitreoretinal procedures underwent LTS. All patients had undergone complex vitreoretinal surgery with attached retinas postoperatively but with persistent hypotony and poor vision. INTERVENTION: Laser trabecular sclerosis was performed in a fashion similar to laser trabeculoplasty, using a 100-microm spot, 800 to 1000 mW power at 0.1 seconds, and applying heavy confluent treatment in >/=1 sessions throughout the angle where trabecular meshwork was visible. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), best spectacle-corrected visual acuity, and complications were studied. RESULTS: In 1 patient, a single session of LTS was followed by an increase in IOP of approximately 4 mm, with subjective and objective improvement in vision. A second patient exhibited improvement in IOP and visual acuity after 3 sessions of LTS. A third patient underwent 3 sessions of LTS without improvement in IOP or vision. CONCLUSION: Given the limitations of this small series, including the lack of a randomized prospective design, it is not possible to determine the safety or efficacy of LTS, but this study does suggest that this procedure could play a therapeutic role in some patients with chronic symptomatic hypotony after complex intraocular surgery. Further study is warranted.  相似文献   
50.
5-Aminoisoquinolinone reduces colon injury by experimental colitis   总被引:4,自引:0,他引:4  
Poly (ADP-ribose) polymerase (PARP), a nuclear enzyme activated by strand breaks in DNA, plays an important role in the colon injury associated with experimental colitis. The aim of the present study was to examine the effects of 5-aminoisoquinolinone (5-AIQ), a novel and potent inhibitor of PARP activity, in the development of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). Compared with DNBS-treated mice, mice treated with 5-AIQ (3 mg/kg i.p.) or 3-aminobenzamide (3-AB; 10 mg/kg i.p. twice a day) and subjected to DNBS-induced colitis experienced a significantly lower rate in the extent and severity of the histological signs of colon injury. DNBS-treated mice experienced diarrhea and weight loss. Four days after administration of DNBS, the mucosa of the colon exhibited large areas of necrosis. Neutrophil infiltration (determined by histology as well as an increase in myeloperoxidase [MPO] activity in the mucosa) was associated with an up-regulation of intercellular adhesion molecule-1 (ICAM-1). Immunohistochemistry for PAR showed an intense staining in the inflamed colon. On the contrary, the treatment of DNBS-treated mice with 5-AIQ or with 3-AB significantly reduced the degree of hemorrhagic diarrhea and weight loss caused by administration of DNBS. 5-AIQ also caused a substantial reduction in the degree of colon injury, in the rise in MPO activity (mucosa), in the increase in staining (immunohistochemistry) for PAR, as well as in the up-regulation of ICAM-1 caused by DNBS in the colon. Thus, 5-AIQ treatment reduces the degree of colitis caused by DNBS. We propose that 5-AIQ treatment may be useful in the treatment of inflammatory bowel disease.  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