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   11481篇
  免费   700篇
  国内免费   51篇
耳鼻咽喉   302篇
儿科学   294篇
妇产科学   306篇
基础医学   1591篇
口腔科学   424篇
临床医学   928篇
内科学   2676篇
皮肤病学   208篇
神经病学   1272篇
特种医学   233篇
外科学   1078篇
综合类   23篇
一般理论   5篇
预防医学   686篇
眼科学   134篇
药学   731篇
  1篇
中国医学   37篇
肿瘤学   1303篇
  2024年   56篇
  2023年   125篇
  2022年   277篇
  2021年   432篇
  2020年   285篇
  2019年   319篇
  2018年   350篇
  2017年   291篇
  2016年   350篇
  2015年   371篇
  2014年   497篇
  2013年   614篇
  2012年   938篇
  2011年   1054篇
  2010年   521篇
  2009年   455篇
  2008年   796篇
  2007年   724篇
  2006年   650篇
  2005年   685篇
  2004年   620篇
  2003年   573篇
  2002年   490篇
  2001年   69篇
  2000年   45篇
  1999年   66篇
  1998年   94篇
  1997年   67篇
  1996年   52篇
  1995年   48篇
  1994年   38篇
  1993年   35篇
  1992年   33篇
  1991年   23篇
  1990年   19篇
  1989年   19篇
  1988年   20篇
  1987年   11篇
  1986年   25篇
  1985年   17篇
  1984年   10篇
  1983年   11篇
  1982年   11篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1976年   4篇
  1974年   4篇
  1972年   5篇
  1967年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The study discusses the construct of spontaneity and its causal relationship with psychological well-being. It develops a preview phase of validation of the SAI-R and its correlation with the Clinical Outcomes for Routine Evaluation-Outcome Measure (CORE-OM) and the Beck Depression Inventory (BDI-II) and assumes the hypothesis that a high level of spontaneity is correlated negatively with low level of well-being and positively with depression. The research involved Italian and Austrian participants, consisting of 166 Italian and 146 Austrian university students. The findings suggested a causal relationship between low spontaneity and psychological suffering. The results obtained confirm the hypothesized model, showing significant negative causal relationship. The verification of this theoretical model on non-clinical samples allows us to set the ground for future use in clinical samples. Furthermore, this result encourages the development of further research into the use of SAI-R.  相似文献   
82.
Epidermoid cysts represent the most common cutaneous cysts. They are usually small and benign; however, sometimes they can grow to giant epidermoid cists, and occasionally malignancies develop. Giant epidermoid cysts at the earlobe have never been described but in other locations. We describe a case of a giant epidermoid cyst at the earlobe, a location where such a large cyst has never been reported before. The mass was completely resected and the wound of the pedunculated base was sutured with four stitches of nylon 5/0. Histopathology confirmed the presumptive diagnosis of an epidermoid cyst. Six months after the resection, the patient did not have any relapse of the epidermoid cyst. The earlobe is a potential location for giant epidermoid cysts. Although the clinical diagnosis could be enough, due to the possibility of malignancy and to ensure appropriate diagnosis, we consider that all cysts should be sent to the anatomic pathology laboratory for histological evaluation.  相似文献   
83.
Atheroembolic renal disease (AERD) is part of a multisystemic disease accompanied by high cardiovascular comorbidity and mortality. Interrelationships between traditional risk factors for atherosclerosis, vascular comorbidities, precipitating factors, and markers of clinical severity of the disease in determining outcome remain poorly understood. Patients with AERD presenting to a single center between 1996 and 2002 were followed-up with prospective collection of clinical and biochemical data. The major outcomes included end-stage renal disease (ESRD) and death. Ninety-five patients were identified (81 male). AERD was iatrogenic in 87%. Mean age was 71.4 yr. Twenty-three patients (24%) developed ESRD; 36 patients (37.9%) died. Cox regression analysis showed that significant independent predictors of ESRD were long-standing hypertension (hazard ratio [HR] = 1.1; P < 0.001) and preexisting chronic renal impairment (HR = 2.12; P = 0.02); use of statins was independently associated with decreased risk of ESRD (HR = 0.02; P = 0.003). Age (HR = 1.09; P = 0.009), diabetes (HR = 2.55; P = 0.034), and ESRD (HR = 2.21; P = 0.029) were independent risk factors for patient mortality; male gender was independently associated with decreased risk of death (HR = 0.27; P = 0.007). Cardiovascular comorbidities, precipitating factors, and clinical severity of AERD had no prognostic impact on renal and patient survival. It is concluded that AERD has a strong clinical impact on patient and renal survival. The study clearly shows the importance of preexisting chronic renal impairment in determining both renal and patient outcome, this latter being mediated by the development of ESRD. The protective effect of statins on the development of ESRD should be evaluated in a prospective study.  相似文献   
84.
Endoscopic endonasal approach to the pterygopalatine fossa: anatomic study   总被引:21,自引:0,他引:21  
Alfieri A  Jho HD  Schettino R  Tschabitscher M 《Neurosurgery》2003,52(2):374-78; discussion 378-80
OBJECTIVE: The pterygopalatine fossa is a relatively small anatomic region. Because of its rich vasculonervous contents and its connections with several intracranial and extracranial compartments, it is of particular surgical interest. Because of its deep localization and despite its small size, however, it can require extensive anatomic approaches, especially for invasive cranial base lesions. We performed a cadaveric study through a minimally invasive endoscopic endonasal approach to the pterygopalatine fossa. METHODS: We studied 16 pterygopalatine fossae in eight adult cadaveric heads in which the arteries and veins were injected with latex. For visualization, we used rod-lens endoscopes, 4 mm in diameter and 18 cm in length, with 0-, 30-, 45-, and 70-degree lenses. An endonasal middle meatal transpalatine approach, an endonasal middle meatal transantral approach, and an endonasal inferior turbinectomy transantral approach were used. RESULTS: The middle meatal transpalatine approach allows for medial exposure of the pterygopalatine fossa contents, the middle meatal transantral approach allows a lateral view, and the inferior turbinectomy transantral approach allows the widest view and room for surgical maneuvering in the medial and lateral compartments of the pterygopalatine fossa and the infratemporal fossa. CONCLUSION: Our anatomic study shows that this approach can be considered a valid minimally invasive option to approach pterygopalatine fossa lesions.  相似文献   
85.
OBJECTIVES: To compare the efficacy of bicalutamide monotherapy to maximal androgen blockade in advanced prostatic cancer. PATIENTS AND METHODS: Previously untreated patients with histologically proven stage C or D (American Urological Association Staging System) disease were randomly allocated to either bicalutamide (B) or goserelin plus flutamide (G+F). After disease progression, patients treated with B were assigned to castration. The primary endpoint for this trial was overall survival. Prostate cancer-specific survival and progression were included among secondary endpoints. RESULTS: In total 108 patients received B and 112 received G+F. At a median follow-up time of 54 months (range 1-89), 151 patients progressed and 113 died. There was no significant difference in the duration of either progression-free or overall survival. Hazards of progression, death and cancer-specific death, corrected by disease stage, tumor grade and baseline PSA level, showed that patients initially assigned to B had a higher risk of progression but a comparable risk of death and cancer-specific death with the exception of patients with G3 tumors who had an increased risk of death). CONCLUSIONS: In patients with well or moderately well differentiated tumors, B monotherapy followed by castration may offer the same survival chance as maximal androgen deprivation. In those patients it thus represents a reasonable choice that can avoid the side effects of androgen deprivation for considerable periods of time.  相似文献   
86.
The aim of this study was to evaluate the influence of laparoscopic Palomo varicocelectomy on testicular volume and sperm parameters. Laparoscopic Palomo varicocelectomy was performed on 91 patients for left-sided grade II and grade III varicoceles. Ultrasound-derived testicular volumes, semen volume, sperm concentration, percentage sperm motility and total motile sperm count were compared before and after the procedure. Postoperative complications and recurrence rate were also assessed. There were no surgical complications. Four patients (5%) had a mild hydrocele, but did not need hydrocelectomy. No patients presented signs of testicular atrophy and the left testicular volume increased in the adolescents (p < 0.05), but not in the adults. Our data suggest that laparoscopic high mass ligation of both the testicular artery and vein is a highly effective, reliable method for the treatment of varicocele. It is associated with very low complication and recurrence rates and with an objective improvement in fertility parameters.  相似文献   
87.
Sodium-sensitive hypertension is thought to be dependent on primary alterations in renal tubular sodium reabsorption. The major apical plasma membrane Na(+) transporters include the proximal tubular Na(+)-H(+) exchanger, the thick ascending limb Na(+)-K(+)-2Cl(-) cotransport system, the distal tubular Na(+)-Cl(-) cotransporter, and the collecting duct epithelial sodium channel (ENaC). This article explores the role of each transporter in the pathogenesis of hypertension. Although the contribution of the proximal tubule Na(+)-H(+) exchanger is not yet defined completely, more convincing data have been generated about the importance of the Na(+)-K(+)-2Cl(-). Indeed at least 2 forms of hypertension appear to be related to the up-regulation of the transporter: the so-called programmed hypertension induced by low-protein diet during pregnancy and the early phase of hypertension in the Milan strain of rats. With respect to the Na(+)-Cl(-) cotransporter this may be overactive caused by inactivating mutation of WNK4 as in the Gordon syndrome, although it is the main actor for the maintenance phase of the hypertension found in the Milan strain of rats. Finally, the contribution of the ENaC has been established clearly; indeed, in the Liddle syndrome the mutation of the ENaC gene leads to a longer retention of the channel on the cell surface of collecting duct principal cells, thus inducing stronger sodium reabsorption along this segment. All these examples clearly indicate that renal sodium transporters may be responsible for various types of sodium-sensitive hypertension.  相似文献   
88.
Both genetics and physical activity (PA) contribute to bone mineral density (BMD), but it is unknown if the benefits of physical activity on childhood bone accretion depend on genetic risk. We, therefore, aimed to determine if PA influenced the effect of bone fragility genetic variants on BMD in childhood. Our sample comprised US children of European ancestry enrolled in the Bone Mineral Density in Childhood Study (N = 918, aged 5 to 19 years, and 52.4% female). We used a questionnaire to estimate hours per day spent in total, high‐, and low‐impact PA. We calculated a BMD genetic score (% BMD lowering alleles) using adult genome‐wide association study (GWAS)‐implicated BMD variants. We used dual‐energy X‐ray absorptiometry to estimate femoral neck, total hip, and spine areal‐BMD and total body less head (TBLH) bone mineral content (BMC) Z‐scores. The BMD genetic score was negatively associated with each bone Z‐score (eg, TBLH‐BMC: estimate = –0.03, p = 1.3 × 10?6). Total PA was positively associated with bone Z‐scores; these associations were driven by time spent in high‐impact PA (eg, TBLH‐BMC: estimate = 0.05, p = 4.0 × 10?10) and were observed even for children with lower than average bone Z‐scores. We found no evidence of PA‐adult genetic score interactions (p interaction > 0.05) at any skeletal site, and there was no evidence of PA‐genetic score–Tanner stage interactions at any skeletal site (p interaction > 0.05). However, exploratory analyses at the individual variant level revealed that PA statistically interacted with rs2887571 (ERC1/WNT5B) to influence TBLH‐BMC in males (p interaction = 7.1 × 10?5), where PA was associated with higher TBLH‐BMC Z‐score among the BMD‐lowering allele carriers (rs2887571 AA homozygotes: estimate = 0.08 [95% CI 0.06, 0.11], p = 2.7 × 10?9). In conclusion, the beneficial effect of PA on bone, especially high‐impact PA, applies to the average child and those genetically predisposed to lower adult BMD (based on GWAS‐implicated BMD variants). Independent replication of our exploratory individual variant findings is warranted. © 2016 American Society for Bone and Mineral Research.  相似文献   
89.

Aim

Surgical myotomy of the lower esophageal sphincter has a 5-year success rate of approximately 91 %. Peroral endoscopic myotomy can provide similar results for controlling dysphagia. Some patients experience either persistent or recurrent dysphagia after myotomy. We present here a retrospective analysis of our experience with redo myotomy for recurrent dysphagia in patients with achalasia.

Methods

From March 1996 to February 2015, 234 myotomies for primary or recurrent achalasia were performed in our center. Fifteen patients (6.4 %) had had a previous myotomy and were undergoing surgical redo myotomy (n?=?9) or endoscopic redo myotomy (n?=?6) for recurrent symptoms.

Results

Patients presented at a median of 10.4 months after previous myotomy. Median preoperative Eckardt score was 6. Among the nine patients undergoing surgical myotomy, three esophageal perforations occurred intraoperatively (all repaired immediately). Surgery lasted 111 and 62 min on average (median) in the surgical and peroral endoscopic myotomy (POEM) groups, respectively. No postoperative complications occurred in either group. Median postoperative stay was 3 and 2.5 days in the surgical and POEM groups, respectively. In the surgical group, Eckardt score was <3 for seven out of nine patients after a mean follow-up of 19 months; it was <3 for all six patients in the POEM group after a mean follow-up of 5 months.

Conclusions

A redo myotomy should be considered in patients who underwent myotomy for achalasia and presenting with recurrent dysphagia. Preliminary results using POEM indicate that the technique can be safely used in patients who have undergone previous surgical myotomy.
  相似文献   
90.

Background

Sentinel lymph node biopsy (SLNB) allows for staging of the axillary node status in early-stage breast cancer (BC) patients and avoiding complete axillary lymph node dissection (ALND) when the sentinel lymph node (SLN) is proven to be free of disease. In a previous randomized trial we compared SLNB followed by ALND (ALND arm) with SLNB followed by ALND only if the SLN presented metastasis (SLNB arm). At a mid-term of ≈ 6 years median follow-up, the two strategies appeared to ensure similar survival and locoregional control. We have revised these previous findings and update the results following a 15-year observation period.

Methods

Patients were randomly assigned to either the ALND or SLNB arm. The main endpoints were event-free survival (EFS), overall survival (OS), and axillary disease recurrence. EFS and OS were assessed using Kaplan–Meier analysis and the log-rank test.

Results

The ALND and SLNB arms included 115 and 110 patients, respectively. At 14.3 years median follow-up, 39 primary BC-related recurrences occurred, 22 (19 %) of which occurred in the ALND arm and 17 (16 %) occurred in the SLNB arm (p = 0.519). No axillary relapse developed in the SLNB arm, while two were observed in the ALND arm. OS (82.0 vs. 78.8 %) and EFS (72.8 vs. 72.9 %) were not statistically different between the ALND and SLNB arms (p = 0.502 and 0.953, respectively).

Conclusions

SLNB is a safe and efficacious component of the surgical treatment of early-stage BC patients. In the long-term, SLNB is equivalent to ALND in terms of locoregional nodal disease control and survival in this subset 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