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   194810篇
  免费   1851篇
  国内免费   93篇
耳鼻咽喉   1255篇
儿科学   6926篇
妇产科学   3222篇
基础医学   18738篇
口腔科学   2126篇
临床医学   13584篇
内科学   35474篇
皮肤病学   1021篇
神经病学   17934篇
特种医学   9850篇
外科学   32264篇
综合类   2400篇
一般理论   1篇
预防医学   18759篇
眼科学   3224篇
药学   10899篇
中国医学   647篇
肿瘤学   18430篇
  2022年   194篇
  2021年   331篇
  2020年   210篇
  2019年   281篇
  2018年   22184篇
  2017年   17562篇
  2016年   19752篇
  2015年   1204篇
  2014年   1169篇
  2013年   1287篇
  2012年   7747篇
  2011年   21861篇
  2010年   19290篇
  2009年   11909篇
  2008年   20238篇
  2007年   22523篇
  2006年   1496篇
  2005年   3063篇
  2004年   4233篇
  2003年   5087篇
  2002年   3291篇
  2001年   1146篇
  2000年   1303篇
  1999年   920篇
  1998年   469篇
  1997年   404篇
  1996年   310篇
  1995年   240篇
  1994年   240篇
  1993年   180篇
  1992年   560篇
  1991年   568篇
  1990年   597篇
  1989年   538篇
  1988年   460篇
  1987年   442篇
  1986年   428篇
  1985年   417篇
  1984年   249篇
  1983年   203篇
  1982年   113篇
  1980年   97篇
  1979年   181篇
  1978年   118篇
  1977年   105篇
  1974年   97篇
  1973年   96篇
  1970年   128篇
  1969年   111篇
  1968年   102篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
991.

Purpose

Several video-assisted and robotic surgery techniques have been reported for resection of the thyroid and parathyroid glands. Our institute has started performing endoscopic thyroidectomy using the Lap-protector and E·Z-access system, referred to as E·Z-access using video-assisted neck surgery (EZ-VANS). In this report, we evaluate the safety and efficacy of this technique.

Methods

From January 2007 to September 2014, 110 patients underwent resection of a primary thyroid tumor, 73 who underwent a cervical collar incision (the Open group) and 37 underwent EZ-VANS (the EZ-VANS group).

Results

The average operating time was 159 and 172 min in the Open group and EZ-VANS group, respectively; the amount of blood loss was 46.5 and 54.7 ml, respectively; and the length of hospital stay after surgery was 4.3 and 5.2 days, respectively, with no significant differences observed between the two groups. The learning curve for the EZ-VANS technique was shorter than for open surgery.

Conclusions

We confirmed that the EZ-VANS technique is a safe and useful method for resection of benign and early malignant thyroid tumors.
  相似文献   
992.

Purpose

We devised a simple dichotomous classification system and showed sufficient reproducibility to indicate treatment strategies for peritoneal metastasis of colorectal cancer.

Methods

We included 67 patients with peritoneal metastasis of colorectal cancer and classified them according to the largest lesion size, number of lesions and number of regional peritoneal metastases. The oncological data were recorded and compared.

Results

According to the univariate analyses, the prognoses were significantly better in patients with ≤3 disseminated lesions than in those with ≥4, and in patients with disseminated lesions in only one region than in those with ≥2 lesions. A multivariate analysis showed that primary tumor resection and the presence of peritoneal metastases in only one region were favorable factors for the patient survival. Patients with disseminated lesions in only one region (localized group) and those with nonlocalized lesions had three-year survival rates of 45.6 and 12.2 %, respectively. Finally, primary tumor resection improved the prognoses in both the localized and nonlocalized groups.

Conclusions

Colorectal cancer patients were categorized into localized and nonlocalized groups according to the number of regions with peritoneal metastasis, and significant prognostic associations were demonstrated. Subsequent analyses of the oncological data suggested that primary tumor resection contributes to an improved prognosis in all patients with synchronous peritoneal metastases.
  相似文献   
993.
Postoperative atrial fibrillation (POAF), the most frequent arrhythmia after pulmonary resection, is a cause of both morbidity and mortality. Being able to predict the risk of POAF before surgery would help us evaluate the surgical risk and plan prophylaxis. We investigated the reported preoperative risk factors associated with the incidence of POAF and found that the recommended predictive factors were quite variable. Therefore, we evaluated the previously reported preoperative risk factors for POAF using our institutional data. We discuss our findings in this short review. Male gender, resected lung volume, brain natriuretic peptide (BNP), and left ventricular early transmitral velocity/mitral annular early diastolic velocity (E/e′) calculated by echocardiography were suggested as independent predictors for POAF, but the predictive values of each individual parameter were not high. The lack of definitive predictors for POAF warrants further investigations by gathering the reported knowledge, to establish an effective preoperative examination strategy.  相似文献   
994.
Hip osteoarthritis is a common cause of musculoskeletal pain in older adults and may result in decreased mobility and quality of life. Although the presentation of hip osteoarthritis varies, surgical management is required when the disease is severe, longstanding, and unresponsive to nonoperative treatments. For stakeholders to plan for the expected increased demand for surgical procedures related to hip osteoarthritis, including arthroplasty, it is important to first understand its prevalence. We conducted a systematic review by searching MEDLINE® and EMBASE to identify recent English language articles reporting on the prevalence of radiographic primary hip osteoarthritis in the general adult population; references including studies and primary studies from previous systematic reviews were also searched. This strategy yielded 23 studies reporting 39 estimates of overall prevalence ranging from 0.9% to 27% with a mean of 8.0% and a standard deviation of 7.0%. Heterogeneity was noted in study populations, eligibility criteria, age and gender distribution, type of radiographs, and method of diagnosis. Although the association between radiographic hip osteoarthritis and the need for eventual surgical management is still unclear, this study supports assertions that hip osteoarthritis is a prevalent condition whose treatment will continue to place important demands on health services.  相似文献   
995.
Objective  This is the first report of the simultaneous combined use of trans-sphenoidal and trans-ventricular-endoscopic route for decompression of a giant pituitary adenoma. Method  A 38 year old man presented to us with symptoms of raised intracranial pressure along with visual and hypothalamic disturbances. The CT scan revealed destruction of the sella by a large (5 × 3.5 × 2.5 cm) well defined enhancing mass in the sella and suprasellar region extending laterally up to the cavernous sinuses and both carotid arteries and superiorly into the lumen of the 3rd ventricle producing obstructive hydrocephalus. On T2WI of the non-contrast MRI scan the mass was iso-intense to grey matter suggesting the possibility of a firm nature of the adenoma. The tumour was first approached by the standard trans-sphenoidal route and as predicted from the pre-operative MRI, the tumour was found to be firm and not amenable to suction. After decompression of the intra-sellar part of the tumour, the intracranial pressure was raised in an attempt to make the remainder of the tumour descend into the sella but without success. The suprasellar part of the tumour was then simultaneously addressed via a trans-ventricular-endoscopic route but the firm tumour did not yield to endoscopic instruments viz. biopsy forceps, angiographic catheter and electrosurgical probes. It was then gently pushed down towards the sella and decompressed piecemeal by using trans-sphenoidal instruments. The sellar cavity was reconstructed using fat, fascia lata graft and a piece of septal bone. Results  Post-operatively, the patient showed a remarkable improvement of his symptoms of raised intracranial pressure, hypothalamic dysfunction and visual disturbances. Follow-up imaging at 2 months and 1 year, did not show any residual or recurrent tumour. Conclusions  This novel technique of the combined trans-sphenoidal and simultaneous trans-ventricular-endoscopic approach is a viable option for patients with giant fibrous pituitary adenoma when the tumour is not yielding to the trans-sphenoidal route alone.  相似文献   
996.
Objective  To assess the main characteristics of late relapsing malignant germ cell tumors (MGCTs). These tumors are rare and occur by definition 2 years or later after successful treatment. Methods  We present relevant literature on relapsing MGCT in order to highlight the following issues: incidence, impact of initial treatment on the subsequent risk of late relapse, treatment, and survival. Results  A pooled analysis of 5,880 patients with MGCT revealed late relapses in 119 of 3,704 (3.2%) and in 31 of 2,176 (1.4%) patients with non-seminoma and seminoma, respectively. The retroperitoneal space is the predominant site of relapse in both histological types. The initial treatment is important for the risk and localization of late relapses. Patients with single site teratoma are usually cured by surgery alone, whereas viable MGCT or teratoma with malignant transformation may require multimodal treatment with chemo- and/or radiotherapy as well as surgery. Surgery is the most important part in the treatment of late relapses. Salvage chemotherapy should, if feasible, be based on a representative biopsy. Five-year cancer-specific survival is above 50% in the recent large series and reaches 100% in case of single site teratoma. Conclusions  Treatment of late relapsing MGCT patients is challenging and should be performed in experienced centers only. Referral of late relapsing patients to high-volume institutions ensures the best chances of cure and enables multimodal treatment, and contributes to increased knowledge of tumor biology as well experience with the clinical course of these patients.  相似文献   
997.
Purpose  There has been a changing preference for bioprosthetic valves over mechanical valves in dialysis patients, but there is still much controversy. We reviewed our 17-year experience and assessed the influence of prosthesis choice. Methods  From 1990 to 2007, a total of 63 consecutive dialysis patients who underwent valvular surgery (64 operations including one reoperation) at our hospital were retrospectively reviewed. The mean age of the patients was 58.3 ± 9.0 years. The reasons for dialysis were glomerulonephritis (n = 32) and diabetes (n = 10). The major preoperative diagnosis was aortic stenosis (n = 44). The surgical procedures included aortic valve replacement (n = 44), mitral valve replacement (n = 7), double valvular replacement (n = 7), and mitral valve repair (n = 5). Prostheses for valve replacement were mechanical valves (n = 37) or bioprosthetic valves (n = 22). Follow-up was accomplished in 95.2%, and the mean follow-up period was 49 months. Results  Actuarial survivals at 1, 5, and 10 years were 85%, 64%, and 45% respectively. Freedom from cardiovascular events at 1 and 5 years was 61% and 41%, respectively. Mechanical valve patients had significantly higher early mortality than bioprosthetic valve patients (P = 0.03). However, both mechanical and bioprosthetic valve patients had similar survival and event-free rates (P = 0.87 and P = 0.27, respectively) in the midterm results. The mechanical group had a higher rate of bleeding events. There was no structural valve deterioration up to the 5-year follow-up. Conclusion  The choice of prosthesis did not influence the surgical outcome except for early mortality. Careful consideration of preventive measures against bleeding is important, and prosthesis selection should be based on the patient’s profile as well as the criteria for nondialysis patients.  相似文献   
998.
Background  Radiosurgery is an effective treatment option for patients with small to medium sized arteriovenous malformations. However, it is not generally accepted as an effective tool for larger (>14 cm3) arteriovenous malformations because of low obliteration rates. The authors assessed the applicability and effectiveness of radiosurgery for large arteriovenous malformations. Method  We performed a retrospective study of 46 consecutive patients with more than 14 ml of arteriovenous malformations who were treated with radiosurgery using a linear accelerator and gamma knife (GK). They were grouped according to their initial clinical presentation—17 presented with and 29 without haemorrhage. To assess the effect of embolization, these 46 patients were also regrouped into two subgroups—25 with and 21 without preradiosurgical embolization. Arteriovenous malformations found to have been incompletely obliterated after 3-year follow-up neuroimaging studies were re-treated using a GK. Findings  The mean treatment volume was 29.5 ml (range, 14.0–65.0) and the mean marginal dose was 14.1 Gy (range, 10.0–20.0). The mean clinical follow-up periods after initial radiosurgery was 78.1 months (range, 34.0–166.4). Depending on the results of the angiography, 11 of 33 patients after the first radiosurgery and three of four patients after the second radiosurgery showed complete obliteration. Twenty patients received the second radiosurgery and their mean volume was significantly smaller than their initial volume (P = 0.017). The annual haemorrhage rate after radiosurgery was 2.9% in the haemorrhage group (mean follow-up 73.3 months) and 3.1% in the nonhaemorrhage group (mean follow-up 66.5 months) (P = 0.941). Preradiosurgical embolization increased the risk of haemorrhage for the nonhaemorrhage group (HR, 28.03; 95% CI, 1.08–6,759.64; P = 0.039), whereas it had no effect on the haemorrhage group. Latency period haemorrhage occurred in eight patients in the embolization group, but in no patient in the nonembolization group (P = 0.004). Conclusions  Radiosurgery may be a safe and effective arteriovenous malformation treatment method that is worth considering as an alternative treatment option for a large arteriovenous malformation.  相似文献   
999.
1000.
In this prospective study, our aim was to compare the clinical outcome of posterior lumbar interbody fusion (PLIF) and posterolateral fusion (PLF) in spondylolisthesis. A total of 138 patients with spondylolisthesis were randomly assigned to two groups: those operated on with pedicle screw fixation and posterior lumbar interbody fusion by autografting (PLIF), and those operated on with pedicle screw fixation and posterolateral fusion by autografting (PLF). The patients were followed-up for four years. Clinical evaluation was carried out using the Oswestry disability index (ODI) and pain index (VAS). Radiography was performed preoperatively and postoperatively to assess the fusion. Both surgical procedures were effective, but the PLF group showed more complications related to hardware biomechanics. There was no significant statistical difference in clinical and functional outcome in the two groups. The PLIF group presented a better fusion rate than the PLF group.  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