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   892篇
  免费   34篇
  国内免费   4篇
耳鼻咽喉   17篇
儿科学   106篇
妇产科学   18篇
基础医学   69篇
口腔科学   13篇
临床医学   54篇
内科学   140篇
皮肤病学   53篇
神经病学   55篇
特种医学   15篇
外科学   157篇
综合类   25篇
预防医学   47篇
眼科学   64篇
药学   41篇
中国医学   4篇
肿瘤学   52篇
  2023年   3篇
  2022年   17篇
  2021年   41篇
  2020年   16篇
  2019年   31篇
  2018年   31篇
  2017年   28篇
  2016年   21篇
  2015年   28篇
  2014年   26篇
  2013年   35篇
  2012年   49篇
  2011年   34篇
  2010年   30篇
  2009年   23篇
  2008年   42篇
  2007年   38篇
  2006年   46篇
  2005年   44篇
  2004年   43篇
  2003年   34篇
  2002年   31篇
  2001年   25篇
  2000年   22篇
  1999年   19篇
  1998年   12篇
  1997年   5篇
  1996年   9篇
  1995年   15篇
  1994年   7篇
  1993年   3篇
  1992年   18篇
  1991年   7篇
  1990年   8篇
  1989年   10篇
  1988年   11篇
  1987年   10篇
  1986年   10篇
  1985年   11篇
  1984年   8篇
  1983年   5篇
  1982年   3篇
  1979年   3篇
  1974年   3篇
  1973年   2篇
  1969年   1篇
  1967年   1篇
  1965年   1篇
  1957年   1篇
  1949年   1篇
排序方式: 共有930条查询结果,搜索用时 0 毫秒
51.
Particle migration is one of the main concerns raised when implanted plastics are discussed, especially when used for the endoscopic treatment of vesicoureteric reflux in children. To study the histological response to migrated plastic material, we injected particulate plastics (Teflon and silicone) into the jugular vein of 21 Sprague-Dawley rats, 11 of which were killed at 12 months, 9 at 2 years, and 1 died at 18 months. The findings were similar for Teflon and silicone and unchanged after from 1 to 2 years. The plastic particles were seen outside pulmonary vessels, within aggregated multinucleate giant cells, surrounded by only small numbers of other types of inflammatory cells.  相似文献   
52.
A 9-month-old boy presented with the complaints of loose motion, vomiting and difficulty in breathing. His scalp hairs were thin, brittle, and sparse and were of differing lengths with twisted appearance. Hair shaft microscopy revealed alternate light and dark segments and twisting of the hair shafts by 180 degrees along the axis. Serum copper levels were normal. The audiological testing revealed bilateral sensorineural hearing loss. Child was diagnosed as a case of Bjornstad Syndrome.  相似文献   
53.
54.
PURPOSE: The purpose of this study was to prepare large-porous peptide-encapsulating polymeric particles with low residual solvent that retain deslorelin integrity, sustain drug release, and exhibit reduced epithelial and macrophage uptake. We hypothesized that supercritical carbon dioxide (SC CO2) pressure-quench treatment of microparticles prepared using conventional approach expands these particles and extracts the residual organic solvent. METHODS: Initial studies with crystalline L-lactide (L-PLA) and amorphous copolymers of lactide-co-glycolide (PLGA) 50:50, 65:35, and 75:25 indicated that PLGA 50:50 was the most amenable to morphological changes upon SC CO2 treatment. Therefore, we prepared deslorelin-PLGA (50:50) microparticles using the conventional emulsion-solvent evaporation method, and in a second step equilibrated with SC CO2 at various temperatures (33-37 degrees C) and pressures (1200-2000 psi) for discrete intervals followed by rapid isothermal depressurization. The particles were then characterized for morphology, polymer thermal properties, particle size, porosity, bulk density, and residual solvent content. Also, deslorelin integrity, conformation, release, and cellular uptake before and after SC CO2 treatment was determined. RESULTS: Upon SC CO2 treatment (1200 psi, 33 degrees C for 30 min), the mean particle size of the deslorelin PLGA microparticles increased from 2.2 to 13.8 microm, the mean porosity increased from 39 to 92.38% the mean pore diameter increased from 90 to 190 nm, the mean bulk density reduced from 0.7 to 0.082 g/cc, mass spectrometry indicated structural integrity of released deslorelin, the circular dichroism spectrum indicated stabilization of beta-turn conformation, and the scanning electron microscopy confirmed increased particle size and pore formation. The deslorelin release was sustained during the 7-day study period. Also, the peak Tg of PLGA decreased from 51 to 45 degrees C, and the residual solvent content was reduced from 4500 ppm to below detection limit (< 25 ppm). The accumulation of drug from SC CO2 treated particles in cell layers of Calu-3, A549, and rat alveolar macrophages was reduced by 87, 91 and 50%, respectively, compared to untreated particles. CONCLUSION: An SCF-derived process could be successfully applied to prepare large porous deslorelin-PLGA particles with reduced residual solvent content, which retained deslorelin integrity, sustained deslorelin release, and reduced cellular uptake.  相似文献   
55.
INTRODUCTION: A number of families in a rural area of Jabalpur District (Madhya Pradesh), India, were affected by repeated episodes of convulsive illness over a period of three weeks. The aim of this investigation was to determine the cause of the illness. METHODS: The investigation included a house-to-house survey, interviews of affected families, discussions with treating physicians, and examination of hospital records. Endosulfan poisoning was suspected as many villagers were using empty pesticide containers for food storage. To confirm this, our team collected blood and food samples, which were transported to the laboratory and analyzed with GC-ECD. RESULTS: Thirty-six persons of all age groups had illness of varying severity over a period of three weeks. In the first week, due to superstitions and lack of treatment, three children died. In the second week, symptomatic treatment of affected persons in a district hospital led to recovery but recurrence of convulsive episodes occurred after the return home. In the third week, 10 people were again hospitalized in a teaching hospital. Investigations carried out in this hospital ruled out infective etiology but no facilities were available for chemical analysis. All persons responded to symptomatic treatment. The blood and food samples analyzed by our team showed presence of endosulfan, which was confirmed by GCMS. One of the food items (Laddu) prepared from wheat flour was found to contain 676 ppm of alpha-endosulfan. CONCLUSIONS: Contamination of wheat grains or flour with endosulfan and its consumption over a period of time was the most likely cause of repeated episodes of convulsions, but the exact reason for this contamination could not be determined. This report highlights the unsafe disposal of pesticide containers by illiterate farm workers, superstitions leading to delay in treatment, and susceptibility of children to endosulfan.  相似文献   
56.
57.
A retrospective study was performed of 250 patients with cholelithiasis treated at the Royal Children's Hospital, (RCH) Melbourne, over 25 years by open operation; 32 (12.8%) had proven choledocholithiasis on either preoperative imaging, operative cholangiography (OpCG), or postoperative investigation. A further 3 had underlying congenital biliary abnormalities and were excluded from further study. Thirty-one of the 32 were explored at open operation, 27 after OpCG and 4 on clinical grounds. One retained common-bile-duct (CBD) stone was undetected until the postoperative period (1/250, 0.25%). Seven ducts were not cleared, giving a duct exploration failure rate of 22.6% (7/31). All 8 retained CBD stones were identified in the early postoperative period and managed with a variety of techniques, including endoscopic retrograde cholangio-pancreatography (ERCP). The incidence of retained stones after open CBD exploration was high (22.6%), and can be attributed to difficulties in operative technique dealing with the smaller paediatric CBD. In addition, haemolytic disease seems to induce a propensity for choledocholithiasis. Given the small numbers presenting with cholelithiasis to RCH (10 per year), it is suggested that a selective approach to CBD exploration is appropriate in children. With the increasing use of laparoscopic cholecystectomy in children and the inherent technical difficulties of laparoscopic operative cholangiography, ERCP may offer an alternative solution in dealing with CBD stones rather than open or laparoscopic CBD exploration.  相似文献   
58.
Although uterine distension in rats results in an escape reflex, there exists no model of uterine cervical distension (UCD), the pain stimulus during the first stage of labor. The aims of this study were to develop such a model in virgin rats and to test whether peripherally restricted kappa opioid receptor (KOR) agonists (ADL 10-0101, ADL 10-0102, ADL 10-0116) inhibit responses to UCD. Under intravenous (i.v.) pentobarbital and alpha-chloralose anesthesia, fine metal rods were inserted in both uterine cervical osses through a small midline laparotomy. UCD was performed by manual separation of the rods (25-100 g). Single-unit afferent responses in hypogastric nerve or reflex rectus abdominis electromyographic (EMG) activity were determined before and after i.v. KOR agonists. UCD resulted in a stimulus-dependent increase in single-unit afferent activity. Units could be characterized as low threshold (mean threshold 6.6+/-2.7 g), or high threshold (mean threshold 55+/-8.8 g); all were C fibers, all responded to topical bradykinin. ADL 10-0116 (10 mg/kg) reduced the afferent response to UCD. Reflex EMG response occurred over a distension force range of 25-100 g, unaffected by i.v. saline. All three KOR agonists produced a dose-dependent, naloxone-reversible inhibition of the EMG response with a potency relationship of ADL 10-0102 (ED50 0.04 mg/kg)>ADL 10-0101 (ED50 0.65 mg/kg)=ADL 10-0116 (ED50 0.60 mg/kg). These data support the use of acute UCD as a noxious stimulus, inducing afferent and reflex activity. Like other visceral stimuli, UCD is sensitive to inhibition by KOR agonists.  相似文献   
59.
Twelve patients who had a revision posterior sagittal anorectoplasty (PSARP) were evaluated by questionnaire. They were 11 months to 15 years old (median 5 years) at the time of revision surgery. All were born with an intermediate to high anorectal anomaly (ARM) and had ongoing problems of rectal prolapse (3), stenosis (1), faecal incontinence (9), or severe constipation (4). All but 1 had a huge megarectum with a poor anorectal angle and stool impaction, causing overflow incontinence. After revision surgery, marked improvement occurred in 7 and at least some improvement was achieved in the remaining 5. Previous severe constipation resolved in 2 and improved in another 2 children. The number of soiling episodes significantly decreased in 8 patients: while before surgery 8 had been wearing nappies all the time, only 2 use them postoperatively. The anorectal prolapse has resolved in 3 and sensation improved in 5, and as a group, there has been a reduced need for laxatives and rectal washouts. The favourable outcome of our patients confirms that PSARP is an excellent technique for revision surgery, and tapering of a secondary megarectum plus the formation of an anorectal angle can produce clinical improvement, even in more severe forms of ARM. Accepted: 7 February 2001  相似文献   
60.
OBJECTIVE: To study the effects of adjunctive gabapentin on agitation in severely and persistently mentally ill (SPMI) inpatients. METHOD: Eleven chronic SPMI inpatients on stable psychotropic medication regimens were evaluated before and after the initiation of adjunctive gabapentin for six months. The following psychometric tests were used: Brief Psychiatric Rating Scale (BPRS), Corrigan Agitated Behavior Scale (CABS), and Clinical Global Impression (CGI)-Severity. Data collection was accomplished via retrospective chart review. An internal reliability check indicated that a chart review BPRS is significantly predictive of one performed face-to-face. RESULTS: Statistically significant reductions were found at six months for each assessment instrument (p < 0.05, two-tailed). BPRS scores were reduced from 40.6 to 33.2, CABS from 34.4 to 25.0, and CGI-Severity from 5.9 to 5.3. The bulk of the BPRS reduction was accounted for by several subscores exclusive of those assessing affective/anxious symptomatology. Adverse effects were minimal. Two patients were discharged 12 and 17 months after implementation of gabapentin. CONCLUSIONS: Adjunctive gabapentin appears to be associated with a reduction in agitation in chronically hospitalized SPMI patients. Controlled, prospective trials are needed before any definitive conclusion can be drawn regarding the role of gabapentin in the treatment of this group of patients.  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