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   2766篇
  免费   164篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   125篇
妇产科学   48篇
基础医学   314篇
口腔科学   53篇
临床医学   220篇
内科学   651篇
皮肤病学   37篇
神经病学   282篇
特种医学   282篇
外科学   322篇
综合类   37篇
预防医学   297篇
眼科学   11篇
药学   130篇
中国医学   1篇
肿瘤学   117篇
  2022年   13篇
  2021年   25篇
  2019年   13篇
  2018年   37篇
  2017年   40篇
  2016年   28篇
  2015年   39篇
  2014年   48篇
  2013年   73篇
  2012年   79篇
  2011年   90篇
  2010年   74篇
  2009年   83篇
  2008年   93篇
  2007年   89篇
  2006年   91篇
  2005年   106篇
  2004年   91篇
  2003年   86篇
  2002年   78篇
  2001年   87篇
  2000年   58篇
  1999年   75篇
  1998年   69篇
  1997年   84篇
  1996年   70篇
  1995年   59篇
  1994年   62篇
  1993年   59篇
  1992年   55篇
  1991年   62篇
  1990年   52篇
  1989年   66篇
  1988年   78篇
  1987年   58篇
  1986年   60篇
  1985年   71篇
  1984年   52篇
  1983年   61篇
  1982年   41篇
  1981年   39篇
  1980年   38篇
  1979年   36篇
  1978年   31篇
  1977年   27篇
  1976年   28篇
  1975年   32篇
  1974年   28篇
  1971年   12篇
  1969年   17篇
排序方式: 共有2933条查询结果,搜索用时 15 毫秒
41.
PURPOSE: We evaluate terazosin therapy for chronic prostatitis/chronic pelvic pain syndrome. MATERIALS AND METHODS: The study included 100, 20 to-50-year-old subjects who met the consensus criteria for chronic prostatitis/chronic pelvic pain syndrome and had not received previous alpha-blockers. Subjects were randomized to receive terazosin with dose escalation from 1 to 5 mg. daily or placebo for 14 weeks. The primary criterion for response was scoring 2 or less ("delighted-to-mostly satisfied") on the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) quality of life item. The secondary criterion for response was greater than 50% reduction in NIH-CPSI pain score at 14 weeks. Other outcomes included total and NIH-CPSI domain scores, International Prostate Symptom Score, peak urinary flow rate, post-void residual urine and adverse effects. RESULTS: Using the primary criterion 24 of 43 evaluable subjects (56%) responded in the terazosin group compared to 14 of 43 (36%) in the placebo group (p = 0.03). Using the secondary criterion 26 of 43 subjects (60%) responded in the terazosin group compared to 16 of 43 (37%) in the placebo group (p = 0.03). The terazosin group had greater reductions (p <0.05) in NIH-CPSI total score, individual domain scores and International Prostate Symptom Score than the placebo group. There was no difference in peak urinary flow rate or post-void residual. In the terazosin group 18 patients (42%) had side effects compared to 9 (21%) in the placebo group (p = 0.04). CONCLUSIONS: Terazosin proved superior to placebo for patients with chronic prostatitis/chronic pelvic pain syndrome who had not received alpha-blockers previously.  相似文献   
42.
PURPOSE: This review provides practicing urologists with important basic information about urinary tract infections (UTIs) that can be applied to everyday clinical problems. MATERIALS AND METHODS: A review is presented of provocative and controversial concepts in the current literature. RESULTS: Bacterial virulence mechanisms are critical for overcoming the normal host defenses. Increasing antimicrobial resistance of uropathogens has led to reconsideration of traditional treatment recommendations in many areas. For effective patient management the first issue is to define complicating urological factors. Managing complicated urinary tract infections, particularly in urology, is determined by clinical experience to define the pertinent anatomy and to determine the optimal interventions. New clinical data are summarized on UTIs in long-term care patients, behavioral risks for UTI in healthy women and anatomical differences associated with an increased risk for UTI. The rationale is presented for UTI prophylaxis using cranberry juice, immunization and bacterial interference. Current treatment trends for UTI include empiric therapy (without urine culture and sensitivity testing), short-course therapy, patient-administered (self-start) therapy and outpatient therapy for uncomplicated pyelonephritis. CONCLUSIONS: Recommendations for treating patients with UTIs have changed based on basic science and clinical experience.  相似文献   
43.
BACKGROUND: Secondary hyperparathyroidism (SHPT) and its associated abnormalities in mineral metabolism increase the risk of cardiovascular morbidity and death in chronic renal failure (CRF). The effect of parathyroidectomy (PTX) on the incidence of major cardiovascular events in CRF patients with SHPT is unknown. We tested the hypothesis that PTX reduces the incidence of cardiovascular complications and death in CRF patients with severe SHPT scheduled for PTX, comparing the outcome of patients treated or not treated by PTX. METHODS: The study comprised 118 CRF patients with SHPT on maintenance hemodialysis, unresponsive to medical treatment and scheduled for PTX. Patients underwent comprehensive cardiovascular evaluations at baseline. They were followed up until death, occurrence of major cardiovascular events, or kidney transplantation. RESULTS: No deaths related to PTX occurred. After a median follow-up of 30 months, 50 patients (42%) had undergone PTX whereas 68 (58%) had not. The groups were comparable in terms of age, sex, race, serum parathyroid hormone, calcium or phosphate, calcium x phosphate product, and all major cardiovascular variables, except diastolic blood pressure. PTX was associated with a reduced incidence of major cardiovascular events (P = .02) and overall mortality (P 相似文献   
44.
Formation of metastases in the lungs is the major cause of death in patients suffering from osteosarcoma (OS). Metastases at presentation and poor response to preoperative chemotherapy are strong predictors for poor patient outcome. The elucidation of molecular markers that promote metastasis formation and/or chemoresistance is therefore of importance. CD44 is a plasma membrane glycoprotein that binds to the extracellular matrix component hyaluronan (HA) and has been shown to be involved in metastasis formation in a variety of other tumors. Here we investigated the role of CD44 expression on OS tumor formation and metastasis. High CD44 expression, evaluated with a tissue microarray including samples from 53 OS patients and stained with a pan‐CD44 antibody (Hermes3), showed a tendency (p < 0.08) to shortened overall survival. However, nonresponders and patients with lung metastases and high CD44 expression had significantly poorer prognosis than patients with low CD44 expression. Overexpression of the standard CD44 isoform (CD44s) and its HA‐binding defective mutant R41A in osteoblastic SaOS‐2 cells resulted in HA‐independent higher migration rates and increased chemoresistance, partially dependent on HA. In an orthotopic mouse model of OS, overexpression of CD44s in SaOS‐2 cells resulted in an HA‐dependent increased primary tumor formation and increased numbers of micrometastases and macrometastases in the lungs. In conclusion, although CD44 failed to be an independent predictor for patient outcome in this limited cohort of OS patients, increased CD44 expression was associated with even worse survival in patients with chemoresistance and with lung metastases. CD44‐associated chemoresistance was also observed in vitro, and increased formation of lung metastases was found in vivo in SCID mice. © 2013 American Society for Bone and Mineral Research.  相似文献   
45.
OBJECTIVE: Based on our previous pilot study, the objective of this extended study was to compare (a) casts to their corresponding digital ClinCheck? models at baseline and (b) the tooth movement achieved at the end of aligner therapy (Invisalign?) to the predicted movement in the anterior region. MATERIALS AND METHODS: Pre- and post-treatment casts as well as initial and final ClinChecks? models of 50?patients (15-63?years of age) were analyzed. All patients were treated with Invisalign? (Align Technology, Santa Clara, CA, USA). Evaluated parameters were: upper/lower anterior arch length and intercanine distance, overjet, overbite, dental midline shift, and the irregularity index according to Little. The comparison achieved/predicted tooth movement was tested for equivalence [adjusted 98.57% confidence interval (-?1.00; +?1.00)]. RESULTS: Before treatment the anterior crowding, according to Little, was on average 5.39?mm (minimum 1.50?mm, maximum 14.50?mm) in the upper dentition and 5.96?mm (minimum 2.00?mm, maximum 11.50?mm) in the lower dentition. After treatment the values were reduced to 1.57 mm (minimum 0?mm, maximum 4.5?mm) in the maxilla and 0.82?mm (minimum 0?mm, maximum 2.50?mm) in the mandible. We found slight deviations between pretreatment casts and initialClinCheck? ranging on average from -0.08?mm (SD ±?0.29) for the overjet and up to -0.28?mm (SD ±?0.46) for the upper anterior arch length. The difference between achieved/predicted tooth movements ranged on average from 0.01?mm (SD ±?0.48) for the lower anterior arch length, up to 0.7?mm (SD ±?0.87) for the overbite. All parameters were significantly equivalent except for the overbite (-1.02; -?0.39). CONCLUSION: Performed with aligners (Invisalign?), the resolvement of the partly severe anterior crowding was successfully accomplished. Resolving lower anterior crowding by protrusion of the anterior teeth (i.e., enlargement of the anterior arch length) seems well predictable. The initial ClinCheck? models provided high accuracy compared to the initial casts. The achieved tooth movement was in concordance with the predicted movement for all parameters, except for the overbite.  相似文献   
46.
To define an optimal regimen for mobilizing and collecting peripheral blood progenitor cells (PBPC) for use in allogeneic transplantation, we evaluated the kinetics of mobilization by filgrastim (recombinant met- human granulocyte colony-stimulating factor [r-metHuG-CSF]) in normal volunteers. Filgrastim was injected subcutaneously for up to 10 days at a dose of 3 (n = 10), 5 (n = 5), or 10 micrograms/kg/d (n = 15). A subset of volunteers from each dose cohort underwent a 7L leukapheresis on study day 6 (after 5 days of filgrastim). Granulocyte-macrophage colony-forming cell (GM-CFC) numbers in the blood were maximal after 5 days of filgrastim; a broader peak was evident for CD34+ cells between days 4 and 6. The 95% confidence intervals (CI) for mean number of PBPC per milliliter of blood in the three dose cohorts overlapped on each study day. However, on the peak day, CD34+ cells were significantly higher in the 10 micrograms/kg/d cohort than in a pool of the 3 and 5 micrograms/kg/d cohorts. Mobilization was not significantly influenced by volunteer age or sex. Leukapheresis products obtained at the 10 micrograms/kg/d dose level contained a median GM-CFC number of 93 x 10(4)/kg (range, 50 x 10(4)/kg to 172 x 10(4)/kg). Collections from volunteers receiving lower doses of filgrastim contained a median GM- CFC number of 36 x 10(4)/kg (range, 5 x 10(4)/kg to 204 x 10(4)/kg). The measurement of CD34+ cells per milliliter of blood on the day of leukapheresis predicted the total yield of PBPC in the leukapheresis product (r = .87, P < .0001). Assuming a minimum GM-CFC requirement of 50 x 10(4)/kg (based on our experience with autologous PBPC transplantation), all seven leukapheresis products obtained at the 10 micrograms/kg/d dose level were potentially sufficient for allogeneic transplantation purposes. We conclude that in normal donors, filgrastim 10 micrograms/kg/d for 5 days with a single leukapheresis on the following day is a highly effective regimen for PBPC mobilization and collection. Further studies are required to determine whether PBPC collected with this regimen reliably produce rapid and sustained engraftment in allogeneic recipients.  相似文献   
47.
Medullary carcinoma of the breast: mammographic and US appearance   总被引:4,自引:0,他引:4  
  相似文献   
48.
When infection of prosthetic orthopedic implants is suspected, optimal management requires accurate confirmation or exclusion of infection. The authors retrospectively studied 98 patients with possible infection who underwent scanning with indium-111-labeled white blood cells (WBCs) and subsequently underwent surgery within 14 days. At surgery, 50 patients had infections, as determined by means of culture or histologic results. The diagnostic accuracy of In-111 scanning was compared with that of plain radiography, arthrography, three-phase bone scanning, and various clinical and laboratory findings classically associated with infection. Positive findings on In-111 WBC scans and elevated erythrocyte sedimentation rates were found to be the most predictive variables in the diagnosis of septic prostheses (P less than or equal to .001 and P less than or equal to .002, respectively). Likelihood ratio analysis more clearly demonstrated the superiority of In-111 WBC scanning, with positive and negative scans yielding likelihood ratios of 5.0 and 0.16, respectively.  相似文献   
49.
原发性病原真菌和条件性真菌所致的甲真菌病   总被引:2,自引:1,他引:2  
Pier.  GE 《中华皮肤科杂志》1998,31(5):308-309
近40年间在易感或免疫受损个体中原发性和条件性真菌感染显著增多。其发病率的增加与艾滋病的流行和医疗技术的重大发展,尤其是器官移植、肿瘤及免疫性疾病新的治疗方法相关。在真菌性疾病中,尽管某些人群更易患甲真菌病,但每一个体均可能患该病。虽然甲真菌病呈慢性经过且并不威胁生命,但可严重影响患者的身心健康。甲真菌病的患病率在许多国家似乎呈上升趋势,范围在3%~15%。尽管临床表现可提示有真菌感染,但保证诊断正确和治疗合理仍依赖实验室检查。尽管酵母和霉菌也可成为单独或混合感染的病原菌,但大多数甲真菌病是由皮肤癣菌引起的。…  相似文献   
50.
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