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   4028篇
  免费   170篇
  国内免费   25篇
耳鼻咽喉   35篇
儿科学   109篇
妇产科学   52篇
基础医学   385篇
口腔科学   116篇
临床医学   268篇
内科学   1055篇
皮肤病学   66篇
神经病学   197篇
特种医学   235篇
外科学   761篇
综合类   10篇
现状与发展   1篇
预防医学   73篇
眼科学   39篇
药学   235篇
  1篇
中国医学   8篇
肿瘤学   577篇
  2024年   28篇
  2023年   70篇
  2022年   122篇
  2021年   200篇
  2020年   134篇
  2019年   165篇
  2018年   170篇
  2017年   142篇
  2016年   126篇
  2015年   118篇
  2014年   146篇
  2013年   167篇
  2012年   264篇
  2011年   301篇
  2010年   152篇
  2009年   108篇
  2008年   213篇
  2007年   210篇
  2006年   197篇
  2005年   205篇
  2004年   159篇
  2003年   170篇
  2002年   135篇
  2001年   33篇
  2000年   35篇
  1999年   30篇
  1998年   35篇
  1997年   22篇
  1996年   24篇
  1995年   25篇
  1994年   19篇
  1993年   15篇
  1992年   36篇
  1991年   21篇
  1990年   33篇
  1989年   19篇
  1988年   19篇
  1987年   23篇
  1986年   17篇
  1985年   16篇
  1984年   16篇
  1983年   11篇
  1982年   6篇
  1981年   6篇
  1980年   10篇
  1979年   6篇
  1978年   8篇
  1977年   5篇
  1975年   6篇
  1973年   5篇
排序方式: 共有4223条查询结果,搜索用时 15 毫秒
991.
The effectiveness of thoracoscopic biopsy as a diagnostic method for pleural diseases has been reported; however, obtaining a sufficient specimen size is sometimes difficult. Therefore, an ancillary technique, the precut technique using an injection needle, was devised to address this problem. This study aimed to evaluate the effectiveness and safety of the novel precut technique in patients with undiagnosed pleural effusion.This retrospective study included 22 patients who underwent pleural biopsy using the precut technique to examine exudative pleural effusion of unknown etiology. Thoracoscopy was performed under local anesthesia. The biopsy procedure was performed as follows: a needle was inserted into the pleura around the lesion using a semiflexible thoracoscope; the needle was positioned to make an incision in the pleura while injecting 1% lidocaine with epinephrine and lifting the pleura from the fascia; 2 or 3 precut incision lines were arranged in a triangle; and the specimen was obtained from the parietal pleura using forceps or a cryoprobe. Patient data including age, number of biopsies, biopsy specimen size, pathological and final diagnosis, and postoperative complications were examined.All patients were male with an average age of 74 years. Pleural effusion was found on the right and left sides in 16 and 6 patients, respectively. The average major axis of the biopsy specimens was 18 mm (range, 10–30 mm), which was sufficient to establish a pathological diagnosis. Only 1 patient experienced minor temporal bleeding as a complication.The precut technique enabled the procurement of specimens sufficient in size for pleural biopsy.  相似文献   
992.
993.
Objective Based on the increasing incidence of smell and taste dysfunction among coronavirus disease 2019 (COVID-19) patients, such issues have been considered an early symptom of infection. However, few studies have investigated the type of taste components that are most frequently affected in COVID-19 patients. This study investigated the difference in frequencies of the types of taste component disorders among hospitalized COVID-19 patients. Methods In this retrospective, single-center, observational study, patients'' background characteristics, clinical course, laboratory and radiological findings, and details on taste and/or smell disorders were collected and analyzed from medical records. Patients A total of 227 COVID-19 patients were enrolled, among whom 92 (40.5%) complained of taste disorders. Results Multiple types of taste disorders (hypogeusia/ageusia and hypersensitivity, or hypersensitivity and changing tastes) were reported in 10 patients. In particular, 23 patients reported hypersensitivity to at least 1 type of taste, and 2 patients complained of a bitter taste on consuming sweet foods. Impairment of all taste components was found in 48 patients (52.2%). The most frequent taste disorder was salty taste disorder (81 patients, 89.0%). Hypersensitivity to salty taste was most frequently observed (19 patients, 20.9%). Conclusion Patients with COVID-19 develop multiple types of taste disorders, among which salty taste disorder was the most frequent, with many patients developing hypersensitivity to salty taste. As smell and taste are subjective senses, further studies with the combined use of objective examinations will be required to confirm the findings.  相似文献   
994.
For stage II and III esophageal squamous cell carcinoma (ESCC), neoadjuvant chemotherapy (NAC) followed by esophagectomy is recommended in the Japanese guidelines for the diagnosis and treatment of esophageal cancer. However, recurrence of ESCC is common regardless of the NAC regimen and surgical method, and NAC demonstrates limited efficacy against recurrence. Therefore, the present study was conducted to identify risk factors of recurrence of ESCC with surgery after NAC. The outcomes of 51 patients who underwent esophagectomy for ESCC after NAC from 2010 to 2017 at Kyushu University Hospital were retrospectively analyzed. A total of 52 patients with ESCC without NAC followed by esophagectomy from 2001 to 2017 were selected for comparison. Among patients who underwent NAC followed by surgery, only lymphatic invasion (LY; hazard ratio, 2.761; 95% CI, 1.86-6.43, P=0.018) was an independent factor significantly associated with 3-year recurrence-free survival in the multivariate analysis. In patients with pathologic lymph node metastasis (pN) and no LY after NAC, there was significantly less recurrence compared with patients with pN and LY (P=0.0085), whereas in patients without LY after NAC, the presence of pN was not significantly associated with recurrence (P=0.2401). There were significantly fewer LY (+) patients in the NAC (+) group (P=0.0158) compared with those in the NAC (−) group. The presence of LY was an independent risk factor for recurrence of ESCC after esophagectomy following NAC. Overall, adjuvant treatment after surgery may be required in cases with remnant LY after NAC.  相似文献   
995.
Open in a separate window OBJECTIVESThe possibility of occult metastasis remains a concern when deciding on lung metastasectomy. This study aimed to evaluate the utility of our two-step determination, which required confirmation that no new metastases had occurred over 3 months before surgery.METHODSPatients who were referred for colorectal lung metastases between 2007 and 2015 were reviewed. Immediate wedge resection was performed for cases with a single peripheral metastasis, whereas surgical indications for others were determined by the two-step determination. Early increase was defined as the emergence of new metastases within 4 months after the diagnosis of lung metastases.RESULTSAmong 369 patients included, 92 were unresectable upon initial diagnosis, and 74 with single peripheral metastasis underwent immediate wedge resection. Surgical indications for the remaining 203 patients were ascertained based on the two-step determination. Surgery was not indicated in 48 patients (24%) due to new metastases or a favourable response to chemotherapy, with a median waiting duration of 4.8 months. Those who did not receive surgery had a worse prognosis than those who did (5-year overall survival: 21% vs 69%, P < 0.001) and were comparable to the initially unresectable group (5-year overall survival: 23%). Thirty-eight patients with early increase had lower surgical resection rates and worse prognoses than those without. Multivariable analysis identified early increase as an independent prognostic factor (hazard ratio: 4.49, P < 0.001).CONCLUSIONSPatients with colorectal lung metastasis who developed new metastasis during the waiting period exhibited poor prognosis, suggesting the utility of the two-step determination of surgical indications.  相似文献   
996.
We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients’ head motions and tongue positions.  相似文献   
997.
Background/ObjectiveThe purpose of this study is to develop and validate an instrument to assess interprofessional collaboration by occupational therapists, physical therapists, and speech-language therapists.MethodsItem development consisted of a review of interprofessional collaboration and group interviews with occupational therapists, physical therapists, and speech-language therapists. The developed items were surveyed on a 4-point Likert scale among occupational therapists, physical therapists, and speech-language therapists. Ceiling effects, floor effects, and item-total correlation analysis for each item, as well as constructs, internal consistency, and cross-cultural validity of the scales were evaluated.ResultsA total of 47 items were extracted for evaluation and 28 items with five factors (“team-oriented behavior,” “exchange of opinions,” “flexible response,” “sharing the whole picture of the patient,” and “coordination of support methods”) were retained after the evaluation. The correlation coefficients of the five factors ranged from 0.48 to 0.72. The total score of each factor and the total score of all 28 items were compared for occupational therapists, physical therapists, and speech-language therapists, and the result showed that was no statistically significant difference between the total scores of all factors and the job titles. The Cronbach’s alpha coefficients for the five factors are 0.842, 0.840, 0.805, 0.732, and 0.734 for the first, second, third, fourth, and fifth factors, respectively.ConclusionsThe developed scale includes items aimed at facilitating patients'' activities of daily living through interprofessional collaboration, and its content reflects the expertise of occupational therapists, physical therapists, and speech-language therapists.  相似文献   
998.
The buildup of corrosion products over a reinforcing bar and associated reduction in rib height lead to degradation of the bond between reinforcement and concrete. The authors have previously used digital image correlation (DIC) to visualize and quantify load-induced cracking at the interface in specimens with varying degrees of corrosion. The results obtained in that study are used here to simulate the post-corrosion local bond behavior. A bond degradation model is incorporated into the discrete analysis tool, 3D Rigid Body Spring Model (RBSM) for the simulation. This analysis method allows the shape of the reinforcing bar to be directly modeled, and concrete cracking behavior is simulated by using a randomly shaped mesh. The magnitude of opening and sliding over the tips of ribs in the simulation, in which the reduction in rib height could not be modeled, is significantly lower than observed in the experiment. The results demonstrate that reduction in rib height is an important factor in post-corrosion behavior, and needs to be included in simulation models. It is also understood that in order to gain a better understanding of local post-corrosion bond behavior, de-bonding between reinforcement and concrete needs to be modeled in a discrete analysis framework.  相似文献   
999.
This study used cine-magnetic resonance imaging (cine-MRI) to evaluate the safety and efficacy of a novel airbag system combined with a shell-type body fixation system in reducing respiratory motion in normal volunteers. The airbag system consists of a six-sided polygon inflatable airbag, a same shape plate, a stiff air supply tube, an air-supply pump and a digital pressure load cell monitor. Piezoelectric sensors were installed in the plate to detect compression pressure load changes; pressure load data were transferred to the digital pressure load cell monitor through Bluetooth. Five volunteers underwent cine-MRI with and without airbag compression to detect differences in the respiratory motion of the organs. The volunteers’ physiologic signs were stable during the experiment. The maximum inspiration pressure load was 4.48 ± 0.86 kgf (range, 4.00–6.00 kgf), while the minimum expiration pressure load was 3.69 ± 0.95 kgf (range, 2.8–5.3 kgf). Under airbag compression, the right diaphragm movement was reduced from 19.50 ± 6.43 mm to 9.60 ± 3.61 mm (P < 0.05) in the coronal plane and 23.12 ± 6.30 mm to 11.00 ± 3.69 mm (P < 0.05) in the sagittal plane. The left diaphragm, pancreas and liver in the coronal plane and the right kidney and liver in the sagittal plane also showed significant movement reduction. This novel airbag abdominal compression system was found to be safe during the experiment and successful in the reduction of internal organ respiratory motion and promises to be a convenient and efficient tool for clinical radiotherapy.  相似文献   
1000.
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