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   10132篇
  免费   542篇
  国内免费   78篇
耳鼻咽喉   116篇
儿科学   226篇
妇产科学   184篇
基础医学   1305篇
口腔科学   241篇
临床医学   1039篇
内科学   2414篇
皮肤病学   112篇
神经病学   1179篇
特种医学   353篇
外科学   1669篇
综合类   13篇
预防医学   290篇
眼科学   105篇
药学   609篇
中国医学   12篇
肿瘤学   885篇
  2024年   10篇
  2023年   54篇
  2022年   151篇
  2021年   218篇
  2020年   133篇
  2019年   180篇
  2018年   253篇
  2017年   210篇
  2016年   250篇
  2015年   235篇
  2014年   359篇
  2013年   496篇
  2012年   775篇
  2011年   709篇
  2010年   400篇
  2009年   387篇
  2008年   672篇
  2007年   641篇
  2006年   686篇
  2005年   662篇
  2004年   688篇
  2003年   599篇
  2002年   511篇
  2001年   105篇
  2000年   79篇
  1999年   87篇
  1998年   116篇
  1997年   86篇
  1996年   93篇
  1995年   81篇
  1994年   69篇
  1993年   73篇
  1992年   69篇
  1991年   66篇
  1990年   51篇
  1989年   55篇
  1988年   44篇
  1987年   36篇
  1986年   39篇
  1985年   31篇
  1984年   37篇
  1983年   29篇
  1982年   37篇
  1981年   33篇
  1980年   28篇
  1979年   16篇
  1978年   16篇
  1977年   12篇
  1975年   10篇
  1972年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
In human Y-79 retinoblastoma cells corticotropin-releasing hormone (CRH) produces a marked and rapid increase of adenylate cyclase activity. The concentration of the peptide producing half-maximal stimulation is 60 nM. The effect of CRH is significantly antagonized by the specific CRH receptor antagonist alpha-helical CHR 9-41 and is mimicked by sauvagine and urotensin I, two peptides displaying sequence homology with CRH. These results demonstrate the presence of functional CRH receptors in human Y-79 retinoblastoma cells and suggest that this cell line may be a suitable model in which to study the action of CRH on human retinal cell function.  相似文献   
12.
Endoscopic treatment of benign tumors of the nose and paranasal sinuses.   总被引:1,自引:0,他引:1  
OBJECTIVE: The endoscopic approach can be successfully employed for the treatment of benign tumors such as fibroosseus and vascular lesions, pleomorphic adenomas, gliomas, and schwannomas. STUDY DESIGN AND SETTING: Nineteen patients diagnosed with benign tumors of the nasal cavity and paranasal sinuses and treated using an endoscopic approach were retrospectively reviewed. The endoscopic approach was used exclusively in 15 cases and was associated with an external approach in 4 cases (due to an intracranial extension of the tumor in 3 patients and its location at the level of the anterior wall of the frontal sinus in the last case). RESULTS: The resection of the lesions was radical in 18 patients and subtotal in 1 case. The mean follow-up was 27 months and only 1 recurrence (5%) was observed in the juvenile angiofibroma group 20 months postoperatively. CONCLUSION: and significance In selected cases, endoscopic surgery can be considered an effective treatment for the resection of benign tumors involving the sinonasal tract.  相似文献   
13.
BACKGROUND: We tested the hypothesis that using a subgluteus approach to the sciatic nerve requires a lower concentration of mepivacaine to obtain complete anesthesia as compared with the popliteal approach. METHODS: With midazolam premedication (0.05 mg kg(-1) iv), 48 patients undergoing hallux valgus repair were randomly allocated to receive a sciatic nerve block using either a posterior popliteal (group Popliteal, n = 24) or subgluteus (group Subgluteus, n = 24) approach with 30 mL of local anesthetic injected after elicitation of plantar flexion of the foot with a current 相似文献   
14.
Currently, the best treatment option for idiopathic cervical dystonia (ICD) is injection of botulinum toxin (BTX) into the affected muscles, whereas rehabilitative approaches have given disappointing results. We evaluated whether the association of an ad hoc rehabilitative program may improve the clinical efficacy of BTX treatment in a single-center, cross-over, controlled study. Forty patients with ICD were randomly assigned to two different treatment groups: (1) BTX type A (BTX-A) plus a specific program of physical therapy (BTX-PT) or (2) BTX-A alone (BTX-0). Patients in the BTX-PT group showed a longer duration of the clinical benefit (118.8 vs. 99.1 days) and needed a lower dose of BTX at reinjection (284.5 vs. 325.5 units). In addition, they showed more marked reductions in their disability in activities of daily living (-9.7 vs. -4.85 points) and subjective pain (-13.35 vs. 6.95 points) scores. Association of BTX-A therapy with a specific program of physical therapy may improve ICD treatment outcome.  相似文献   
15.
16.
This article is a retrospective study comparing the efficacy of Regnauld arthroplasty to first ray osteotomies for the treatment of hallux valgus. One hundred consecutive cases of Regnauld arthroplasties were compared with 100 consecutive first ray osteotomies. One hundred fourty-one patients were available for follow-up, and based on clinical/radiographic examinations, 72 were treated with the osteotomy protocol (group A) and 69 with Regnauld arthroplasty (group B). Age at surgery, clinical symptoms, and preoperative radiologic findings were similar for the 2 groups; there was a preponderance of female patients (90%). The average follow-up was 49 months in group A and 51 months in group B. Clinical evaluation showed in the osteotomy group a more stable correction (79% v 49%), greater pain reduction (measured in a visual analog scale from 0 = pain free to 10 = deep intolerable pain), increased residual articular excursion of the first metatarsophalangeal joint (27 degrees of active dorsiflexion from neutral position v 8 degrees ), and less presence of central metatarsalgia (15% v 34%) (P <.05). The radiographic evaluation expressed more stable correction values in group A for the following parameters: joint preservation, sesamoid position, intermetatarsal angle (7 degrees v 12 degrees ), abduction angle of the hallux (14 degrees v 20 degrees ), and proximal articular set angle (8 degrees v 18 degrees ) (P <.05).  相似文献   
17.
The content of dolichol, an isoprenoid present in all biological membranes, was determined in isolated sinusoidal liver cells after treatment of rats for 2 and 4 months with a low dosage of the hepatotoxin thioacetamide. The significant decrease in dolichol observed in hepatocytes after 2 months might be explained by peroxidation of the isoprenoid. At the same time point, retinol was retained, and decreased only after 4 months of treatment. After 4 months of treatment therefore both lipids decreased. In a subfraction of hepatic stellate cells, Ito-1 cells, the main storage site of vitamin A, dolichol decreased significantly only after 4 months. A remarkable difference from hepatocytes is that in Ito-1 cells retinol content significantly decreased after 2 months of treatment. In another subfraction, Ito-2 cells, the content of the two isoprenoids decreased in parallel. This heterogeneous subfraction might represent those transitional hepatic stellate cells that, while losing retinol, are in the process of differentiating into myofibroblasts secreting extracellular matrix components. In Kupffer cells and sinusoidal endothelial cells, impairment of dolichol might be observed later, only after 4 months of treatment, while retinol decreases uniformly over time. Starting after two months of treatment, the decrease of dolichol and the increase of retinol in hepatocytes, at the same time as retinol decreases in hepatic stellate cells, might be taken as an early index of incipient liver injury due to thioacetamide. This hypothesis is discussed with regard to a role of dolichol in the modulation of membrane fluidity for intracellular and intercellular retinol transport.  相似文献   
18.
OBJECTIVES: Recurrent glottic carcinoma after radiotherapy (RT) may be managed by open neck or endoscopic surgery. The impact of endoscopic treatment with CO(2) laser for recurrent glottic carcinoma after RT is reported. METHODS: We present the oncologic and vocal outcomes of a retrospective study based on a series of 16 patients with rT1 and rT2 glottic carcinoma who were endoscopically managed between February 1995 and December 1999 after RT failure. All patients were males with a mean age of 68.7 years (range, 50 to 87 years). Before RT, the lesions had been staged as T1 N0 in 11 patients and T2 N0 in 5, and after RT as rT1 N0 in 12 and rT2 N0 in 4. According to the European Laryngological Society classification, a total of 9 transmuscular, 3 total, and 4 extended cordectomies were performed. Mean follow-up was 45 months (range, 9 to 79 months). RESULTS: Endoscopic salvage surgery was successful in 14 patients. One of them developed a second recurrence and was definitively cured with an additional endoscopic procedure. Two of the 16 patients had recurrent disease after salvage laser surgery and died due to progression of disease. Ultimate local control with laser alone at 3 years was 87.1%, according to the Kaplan-Meier method. Laryngeal preservation was obtained in all survivors after endoscopic rescue surgery. Voice analysis showed a clear correlation between the amount of vocal cord tissue resected and decrease of the vocal outcome. CONCLUSIONS: The present series indicates that selected recurrences after primary RT for T1 and T2 glottic carcinoma are eligible for endoscopic salvage surgery with oncologic results comparable to those with open neck procedures but with a lower complication rate and a favorable functional outcome.  相似文献   
19.
20.
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