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   19347篇
  免费   968篇
  国内免费   144篇
耳鼻咽喉   168篇
儿科学   409篇
妇产科学   150篇
基础医学   2639篇
口腔科学   388篇
临床医学   1236篇
内科学   4987篇
皮肤病学   356篇
神经病学   1758篇
特种医学   715篇
外科学   3225篇
综合类   80篇
预防医学   535篇
眼科学   416篇
药学   1255篇
中国医学   47篇
肿瘤学   2095篇
  2023年   114篇
  2022年   102篇
  2021年   434篇
  2020年   224篇
  2019年   348篇
  2018年   446篇
  2017年   361篇
  2016年   459篇
  2015年   475篇
  2014年   587篇
  2013年   735篇
  2012年   1220篇
  2011年   1373篇
  2010年   736篇
  2009年   623篇
  2008年   1212篇
  2007年   1362篇
  2006年   1264篇
  2005年   1381篇
  2004年   1332篇
  2003年   1306篇
  2002年   1218篇
  2001年   232篇
  2000年   188篇
  1999年   254篇
  1998年   285篇
  1997年   220篇
  1996年   189篇
  1995年   193篇
  1994年   148篇
  1993年   141篇
  1992年   129篇
  1991年   118篇
  1990年   125篇
  1989年   119篇
  1988年   108篇
  1987年   95篇
  1986年   88篇
  1985年   62篇
  1984年   61篇
  1983年   47篇
  1982年   41篇
  1981年   43篇
  1980年   41篇
  1979年   27篇
  1978年   29篇
  1977年   22篇
  1976年   19篇
  1975年   22篇
  1974年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
The present study was undertaken to examine whether the second generation antibiotic drug minocycline attenuates behavioral changes (eg, acute hyperlocomotion and prepulse inhibition (PPI) deficits) in mice after the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist (+)-MK-801 (dizocilpine). Dizocilpine (0.1 mg/kg)-induced hyperlocomotion was significantly attenuated by pretreatment with minocycline (40 mg/kg). Furthermore, the PPI deficits after a single administration of dizocilpine (0.1 mg/kg) were attenuated by pretreatment with minocycline (10, 20, or 40 mg/kg), in a dose-dependent manner. Moreover, in vivo microdialysis study in the free-moving mice revealed that pretreatment with minocycline (40 mg/kg, i.p.) significantly attenuated the increase of extracellular dopamine (DA) levels in the frontal cortex and striatum after administration of dizocilpine (0.1 mg/kg), suggesting that the inhibition of dizocilpine-induced DA release by minocycline may, at least in part, be implicated in the mechanism of action of minocycline with respect to dizocilpine-induced behavioral changes in mice. These findings suggest that minocycline could attenuate behavioral changes in mice after the administration of the NMDA receptor antagonist dizocilpine. Therefore, it is possible that minocycline would be a potential therapeutic drug for schizophrenia.  相似文献   
33.
OBJECTIVE: It is well described that unilateral pelviureteric junction obstruction (PUJO) is a benign condition, because the dilatation resolves spontaneously and the function does not decrease in most of the kidneys. However, there is exceptional PUJO that requires emergent treatment in neonatal periods. The aim of this article is to report the urological emergency and management in neonates with PUJO. MATERIALS AND METHODS: Nine children (seven boys and two girls) with PUJO who underwent neonatal emergent treatment during the last 13 years were reviewed. Renal function was evaluated according to decay curve of serum creatinine (SCr) levels corresponding to gestational age (GA) at delivery. Physical examination, ultrasonographic monitoring, and chest and abdominal plain radiographs were repeated in each neonate. RESULTS: Eight patients were detected prenatally. In five patients, multicystic dysplastic kidney (MCDK) was demonstrated on the contralateral side. Three patients underwent percutaneous puncture of fetal hydronephrosis. Decrease of amniotic fluid was evident in three fetuses. Indications for emergent treatment included mass effect from hydronephrosis in three patients, renal dysfunction in five, and severe urinary tract infection in one. During neonatal periods, a percutaneous nephrostomy tube was placed in seven, and open nephrostomy in one with anorectal malformation. Repeated punctures of the dilated renal pelvis were done in one patient. Renal function after pyeloplasty was stable in eight patients, while it was moderately decreased in one who was associated with oligohydramnios in utero. CONCLUSION: Indications for emergent treatment in neonates with PUJO included mass effect from giant hydronephrosis, renal dysfunction and severe urinary tract infection. At birth, respiratory and circulatory conditions must first be stabilized. In neonates with hydronephrosis of the solitary kidney or severe bilateral PUJO, serial SCr should be monitored to evaluate renal function. Decrease of amniotic fluid suggested renal functional compromise that would not recover after urological management.  相似文献   
34.
OBJECTIVES: We reviewed the results of surgical treatment for children with ureterocele, especially addressing the importance of the lower urinary tract reconstruction. METHODS: We present medical records of 91 children with ureterocele (31 with the intravesical type, and 60 with the ectopic type) treated during the last 14 years. As the initial treatment, we carried out transurethral incision of the ureterocele (TUI). In patients with persistent reflux, breakthrough urinary tract infection (UTI), or signs of bladder outlet obstruction due to a collapsed cele wall, we recommended that patients undergo lower urinary tract reconstruction irrespective of the renal function involved in ureterocele. The average follow-up period was 5 years (ranging 1 year and 6 months to 14 years). RESULTS: Transurethral incision of the ureterocele was carried out as the initial treatment on 68 patients (75%). A total of 34 patients (21 intravesical [68%] and 13 ectopic [22%]) were followed medically after TUI alone. Reconstruction of the lower urinary tract was carried out in 59 patients (65%). Nephroureterectomy combined with bladder level reconstruction was carried out in four children with single system and non-functioning kidney. Follow-up voiding cystourethrography showed that only one girl had reflux, which disappeared after the first follow-up examination. Postoperative UTI occurred in 12 patients (20%) with ectopic ureterocele. Voiding dysfunction was suspected in eight patients. CONCLUSION: We believe that the primary objective for patients with ureterocele, especially of the ectopic type, is to reconstruct the original pathology of the lower urinary tract that may give rise to reflux, obstruction, or abnormalities of urination. Although surgery at the bladder level can be challenging, the lower urinary tract reconstruction successfully corrects the vesicoureteral reflux and bladder outlet pathology under a cosmetically acceptable incision.  相似文献   
35.
PURPOSE: To determine the effect of an interposition nerve graft on sexual function after radical prostatectomy. METHODS: This study includes 64 patients, without hormonal therapy, who underwent a radical prostatectomy and intraoperative electrophysiological confirmation of cavernous nerve preservation. Twelve patients underwent a unilateral interposition sural nerve graft (UNG) for the resected neurovascular bundle. Twenty-one and 31 patients underwent bilateral nerve-sparing (BNS) and unilateral nerve-sparing (UNS) surgery without a nerve graft, respectively. As the age of patients was significantly younger in the UNG group than in the other groups, age-matched analysis also was conducted. Sexual function, evaluated by a self-administered questionnaire using the University of California Los Angeles-Prostate Cancer Index, was compared statistically among the three groups. RESULTS: In the age-matched analysis, the postoperative sexual function (SXF) score of the UNG group showed an intermediate level of recovery between those of the BNS and UNS groups at 12 months and reached the same level as the score at 12 months of the BNS group at 18 months postoperatively. The difference in the SXF score between the UNG and UNS groups began to appear after 6 months postoperatively and increased steadily with time. However, the background factors, such as the baseline SXF score, the usage rate of phosphodiesterase 5 inhibitors, and the rate of comorbidities were different between the UNG and UNS groups. CONCLUSIONS: The difference of the SXF score between the UNG and UNS groups increased with time after 6 months postoperatively. However, it might be difficult at present to attribute a better recovery of the SXF score to the nerve graft because of the difference in the background factors between the groups.  相似文献   
36.
Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.  相似文献   
37.
This report concerns the long-term outcome of living donor liver transplantation (LDLT) for pediatric patients at a single center. Between June 1990 and December 2003, a total of 600 LDLTs, including 568 primary transplantations and 32 retransplantations, were performed for pediatric patients, who were immunosuppressed with FK506 and low-dose corticosteroids. Patient survival at 1, 5, and 10 years were 84.6%, 82.4%, and 77.2%, respectively, and the corresponding findings for graft survivals were 84.1%, 80.9%, and 74.5%. Multivariate analysis demonstrated that fulminant hepatic failure (FHF), a graft vs. body weight (GBWR) ratio of <0.8, and ABO-incompatible transplants were independently associated with both patient and graft survival. The retransplantation rate was 6%, and 55 patients (9.7%) have been completely weaned off immunosuppressants. Long-term patient and graft survival after pediatric LDLT for a large cohort of children at our hospital were found to be as good as those for cadaveric liver transplantation, although this series includes 13% liver transplantations with ABO-incompatible donors, which are obviously inferior in patient and graft survival. To obtain better outcomes for patients with FHF and for patients with ABO-incompatible transplants, immunosuppressive therapy needs to be improved.  相似文献   
38.
Nucleolar organizer regions in meningioma   总被引:1,自引:0,他引:1  
Seventy-eight cases of meningioma and related tumors were examined independently using a simple and reproducible argyrophilic method for the demonstration of nucleolar organizer regions (AgNORs) and staining with bromodeoxyuridine monoclonal antibody. The mean number of AgNORs per cell and the bromodeoxyuridine labeling index were shown to be linearly related (r = 0.84, P less than 0.001). The mean AgNOR number was 2.99 for meningeal sarcoma, 2.29 for anaplastic meningioma, 2.08 for hemangiopericytic meningioma. 1.72 for recurrent meningioma without atypical histological findings, and 1.52 for nonrecurrent meningioma. We noted that the mean number of AgNORs reflected the cellular kinetics of a tumor and was related to histological grade and clinical behavior.  相似文献   
39.
40.
Symptomatic liver cyst: Special reference to surgical management   总被引:2,自引:0,他引:2  
We conducted a retrospective study of 14 patients with symptomatic liver cysts to evaluate current therapeutic interventions for this condition. Abdominal pain (n = 7) or abdominal mass (n = 5) were the most frequent presentations. Three patients also had renal cyst. Percutaneous aspiration with ethanol sclerotheraphy was carried out in 4 patients and all cysts so treated diminished in size, with relief of the symptoms. One patient was treated by aspiration only and re-retension occurred. Cystectomy was performed in 2 patients, unroofing in 5, and fenestration in 2 patients. All patients gained relief of symptoms, with no recurrence of symptoms. Computed tomography revealed that the cysts were diminished or were no longer observable after all the treatments. Our experience indicates that unroofing, fenestration, and cystectomy are safe and suitable procedures for treatment of the condition. Ethanol sclerotherapy may be a feasible alternative to surgical intervention in selected patients. Received for publication on July 23, 1997; accepted on Dec. 25, 1997  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