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   29133篇
  免费   1350篇
  国内免费   158篇
耳鼻咽喉   211篇
儿科学   465篇
妇产科学   316篇
基础医学   3380篇
口腔科学   730篇
临床医学   1909篇
内科学   7073篇
皮肤病学   476篇
神经病学   2210篇
特种医学   1391篇
外科学   5512篇
综合类   124篇
现状与发展   1篇
一般理论   1篇
预防医学   923篇
眼科学   634篇
药学   2067篇
中国医学   32篇
肿瘤学   3186篇
  2023年   148篇
  2022年   312篇
  2021年   514篇
  2020年   321篇
  2019年   422篇
  2018年   522篇
  2017年   418篇
  2016年   545篇
  2015年   536篇
  2014年   668篇
  2013年   883篇
  2012年   1386篇
  2011年   1563篇
  2010年   911篇
  2009年   797篇
  2008年   1411篇
  2007年   1570篇
  2006年   1593篇
  2005年   1530篇
  2004年   1540篇
  2003年   1361篇
  2002年   1381篇
  2001年   969篇
  2000年   972篇
  1999年   854篇
  1998年   391篇
  1997年   299篇
  1996年   315篇
  1995年   220篇
  1994年   218篇
  1993年   181篇
  1992年   581篇
  1991年   522篇
  1990年   515篇
  1989年   491篇
  1988年   436篇
  1987年   422篇
  1986年   422篇
  1985年   403篇
  1984年   244篇
  1983年   194篇
  1982年   101篇
  1979年   184篇
  1978年   122篇
  1977年   104篇
  1975年   87篇
  1973年   95篇
  1972年   91篇
  1970年   109篇
  1969年   92篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.

Purpose

Various techniques are used for sentinel lymph node biopsy (SLNB) in breast cancer. While subareolar injection with dye alone is a relatively easy method, few studies have reported the outcome with a follow-up period. This study presents our results of SLNB using dye alone.

Methods

Between November 2002 and December 2010, 701 patients with breast cancer underwent SLNB using subareolar injection of indocyanine green or indigo carmine. Sentinel lymph node (SLN)-negative patients were followed without axillary lymph node dissection (ALND).

Results

SLNs were detected in 654 of 701 patients (93.3 %), and the rate increased to 98.1 % over the course of the study. The mean number of SLNs removed was 1.5. There was no significant difference in the detection rate between two dyes. No adverse events resulted from the injection of dyes. Of the 654 patients, 136 (20.8 %) had SLN metastasis. Five hundred patients were followed without ALND. Thirty-six patients experienced disease relapse during a median follow-up of 60 months. Thirteen patients (2.6 %) had regional lymph node relapse, and eight of them could undergo salvage lymph node dissection. The 5-year disease-free and overall survival rates were 92.4 and 96.1 %, respectively.

Conclusion

SLNB using subareolar injection with dye alone was safe and feasible even after a long follow-up.  相似文献   
992.

Purpose

The aim of this study was to investigate the outcomes correlated with our treatment strategy for prosthetic graft infection.

Methods

Seventeen patients were treated for prosthetic graft infections between 1997 and 2009. Initially, total graft excision was applied in five cases, partial graft excision was applied in six cases and graft preservation with drainage and irrigation was applied in six cases. Among the graft-preserved cases, four patients were infected with methicillin-resistant Staphylococcus aureus (MRSA) and treated with gentian violet (GV).

Results

The overall survival rate was 88 % at 30 days and 82 % at 1 year in this series. Of the excised cases, nine patients survived; however, two patients died. Among the cases in which MRSA-infected grafts were preserved, three patients survived; however, one patient died under a septicemic state. Infected graft preservation was applied at a high rate of 36 %, and the mortality rate remained at 16 %, without any signs of graft reinfection.

Conclusions

In the treatment of infected grafts, the patient’s condition should be considered in order to select the appropriate treatment in each case. Graft preservation should be considered as an alternative treatment option, especially in high-risk patients, and GV can be effective for conservative treatment of prosthetic graft infections, including MRSA infections.  相似文献   
993.

Purpose

A new diagnosis of chronic obstructive pulmonary disease is often made during the evaluation of patients requiring lung cancer surgery. The objective of the present study was to evaluate the clinical effects of inhaled tiotropium on the postoperative cardiopulmonary complications in patients with untreated chronic obstructive pulmonary disease requiring lung cancer surgery.

Methods

A retrospective study involving 104 consecutive patients with moderate to severe chronic obstructive pulmonary disease who underwent a lobectomy for lung cancer at two specialized thoracic centers between April 2008 and October 2011 was performed. The results were compared between patients who did and did not receive inhaled tiotropium during the perioperative period. The primary endpoint was the incidence of postoperative cardiopulmonary complications. The postoperative white blood cell counts and C-reactive protein levels as biomarkers of inflammation were also examined.

Results

The incidence of postoperative cardiopulmonary complications was significantly lower in the tiotropium group than in the control group (18 vs. 48 %, P = 0.001). Patients in the tiotropium group also showed significantly lower white blood cell counts and C-reactive protein levels postoperatively.

Conclusions

Inhaled tiotropium treatment during the perioperative period had a prophylactic effect on postoperative cardiopulmonary complications in patients with newly diagnosed chronic obstructive pulmonary disease requiring lung cancer surgery.  相似文献   
994.
Palpation is a subjective and non-sharable diagnostic method. Recently, palpation has been supported and replaced by elastography, which provides a novel parameter of “stiffness” as a visual representation or quantified value. Today, elastography is performed using two major modalities: strain elastography and shear wave elastography. Strain elastography converts the extent of deformation during external compression into colors, displaying these colors as a strain map in a motion picture representing the relative elasticity inside the region of interest. Shear wave elastography can quantify the elasticity of a target by calculating the velocity of shear waves generated by a probe. In addition to superficial organs, elastography has also been applied to upper abdominal organs, including the liver, pancreas and spleen. The visualization of the stiffness of focal lesions in the liver or the pancreas has enabled a more sensitive and specific depiction of small, non-palpable nodules, which are difficult to depict using B-mode ultrasonography. The quantification of stiffness also enables non-invasive estimates of liver fibrosis, the risk of postoperative liver insufficiency and the risk of recurrence of viral hepatitis after transplantation. In this article, we review the major reports that have recently been published describing the effective application of elastography to solid upper abdominal organs in a clinical setting.  相似文献   
995.
The role of restorative proctocolectomy with ileal J-pouch anal anastomosis (IPAA) is uncertain for patients with ulcerative colitis (UC), when advanced lower rectal cancer is diagnosed. We report what to our knowledge is the first documented case of successful preoperative chemoradiotherapy followed by IPAA with partial intersphincteric resection of advanced rectal cancer associated with UC. A 59-year-old woman with a 24-year history of extensive UC was found to have advanced rectal cancer located 2 cm from the anal verge. She underwent preoperative conventional chemoradiotherapy followed by restorative proctocolectomy with total mesorectal excision. The procedure included intersphincteric resection of one quadrant and construction of an IPAA with diverting ileostomy. The postoperative course was uneventful, and the ileostomy was closed 6 months after the initial surgery. The patient was doing well with good pouch function and no evidence of recurrent disease 1 year after her initial surgery.  相似文献   
996.

Background

We determined mid to long-term results of total elbow arthroplasty (TEA) by use of unlinked elbow prostheses with solid alumina ceramic trochleae, and ceramic ulnar stems (stemmed Kyocera type I; SKC-I) for patients with rheumatoid arthritis.

Patients and methods

Fifty-four elbows of 39 patients were available for detailed clinical and radiographic review after a follow-up period of at least 5 years. The mean follow-up period was 12.6 years (range 5–22 years). Clinical condition before and after surgery was assessed by use of a modified version of the Mayo Elbow Performance Score (MEPS; 0–100 points) and a Japan Orthopaedic Association Elbow score (JOA score; 0–100 points). The radiographs were reviewed and loosening was defined as a progressive radiolucent line >1 mm wide that was completely circumferential around the prosthesis. Clinical records of post-operative events affecting the elbows were used for survival analysis of the prostheses using the Kaplan–Meier method.

Results

The average modified MEPS and JOA scores improved significantly from 39.7 ± 14.3 to 44.7 ± 9.4, respectively, pre-operatively, to 89.7 ± 15.4 and 83.1 ± 12.8, respectively, post-operatively (P < 0.0001). The functional assessment score also improved from 4.9 ± 2.8 to 8.5 ± 3.3 points (P < 0.0001). With loosening or implant revision defined as end points, the likelihood of survival of the prosthesis for up to 20 years was 92.6 % (95 % confidence interval (CI), 85.6–100.0) or 86.3 % (95 % CI 75.0–97.6), respectively.

Conclusion

Satisfactory clinical results were obtained after TEA using SKC-I prostheses, which provided excellent pain relief and functional range of motion. The results of our study reveal the high reliability over a long period of the cemented SKC-I prosthesis with an alumina ceramic component.  相似文献   
997.
Changes in brain pathology as schizophrenia progresses have been repeatedly suggested by previous studies. Meta-analyses of previous proton magnetic resonance spectroscopy (1H MRS) studies at each clinical stage of schizophrenia indicate that the abnormalities of N-acetylaspartate (NAA) and glutamatergic metabolites change progressively. However, to our knowledge, no single study has addressed the possible differences in 1H MRS abnormalities in subjects at 3 different stages of disease, including those at ultrahigh risk for psychosis (UHR), with first-episode schizophrenia (FES), and with chronic schizophrenia (ChSz). In the current study, 24 patients with UHR, 19 FES, 25 ChSz, and their demographically matched 3 independent control groups (n = 26/19/28 for the UHR, FES, and ChSz control groups, respectively) underwent 1H MRS in a 3-Tesla scanner to examine metabolites in medial prefrontal cortex. The analysis revealed significant decreases in the medial prefrontal NAA and glutamate + glutamine (Glx) levels, specifically in the ChSz group as indexed by a significant interaction between stage (UHR/FES/ChSz) and clinical status (patients/controls) (P = .008). Furthermore, the specificity of NAA and Glx reductions compared with the other metabolites in the patients with ChSz was also supported by a significant interaction between the clinical status and types of metabolites that only occurred at the ChSz stage (P = .001 for NAA, P = .004 for Glx). The present study demonstrates significant differences in 1H MRS abnormalities at different stages of schizophrenia, which potentially correspond to changes in glutamatergic neurotransmission, plasticity, and/or excitotoxicity and regional neuronal integrity with relevance for the progression of schizophrenia.Key words: anterior cingulate cortex, at-risk mental state, biomarkers, frontal lobe, magnetic resonance imaging, neurochemical abnormality  相似文献   
998.
Aim: We have never known any epidemiological study of Arima syndrome since it was first described in 1971. To investigate the number of Arima syndrome patients and clarify the clinical differences between Arima syndrome and Joubert syndrome, we performed the first nationwide survey of Arima syndrome, and herein report its results. Furthermore, we revised the diagnostic criteria for Arima syndrome. Methods: As a primary survey, we sent out self-administered questionnaires to most of the Japanese hospitals with a pediatric clinic, and facilities for persons with severe motor and intellectual disabilities, inquiring as to the number of patients having symptoms of Arima syndrome, including severe psychomotor delay, agenesis or hypoplasia of cerebellar vermis, renal dysfunction, visual dysfunction and with or without ptosis-like appearance. Next, as the second survey, we sent out detailed clinical questionnaires to the institutes having patients with two or more typical symptoms. Results: The response rate of the primary survey was 72.7% of hospitals with pediatric clinic, 63.5% of national hospitals and 66.7% of municipal and private facilities. The number of patients with 5 typical symptoms was 13 and that with 2–4 symptoms was 32. The response rate of the secondary survey was 52% (23 patients). After reviewing clinical features of 23 patients, we identified 7 Arima syndrome patients and 16 Joubert syndrome patients. Progressive renal dysfunction was noticed in all Arima syndrome patients, but in 33% of those with Joubert syndrome. Conclusion: It is sometimes difficult to distinguish Arima syndrome from Joubert syndrome. Some clinicians described a patient with Joubert syndrome and its complications of visual dysfunction and renal dysfunction, whose current diagnosis was Arima syndrome. Thus, the diagnosis of the two syndromes may be confused. Here, we revised the diagnostic criteria for Arima syndrome.  相似文献   
999.
Purpose: Ictal fear is an uncommon condition in which fear manifests as the main feature of epileptic seizures. The literature has suggested that ictal fear is generally associated with poor seizure outcomes. We wanted to clarify the variability in seizure outcome of children with ictal fear. Subjects and methods: We identified five pediatric patients with ictal fear who were followed up on at Okayama University Hospital between January 2003 and December 2012. We retrospectively reviewed their clinical records and EEG findings. Results: The onset age of epilepsy ranged from 8 months to 9 years and 10 months. The common ictal symptoms were sudden fright, clinging to someone nearby, and subsequent impairment of consciousness, which were often accompanied by complex visual hallucinations and psychosis-like complaints. Ictal fear, in four patients, was perceived as a nonepileptic disorder by their parents. Ictal electroencephalograms (EEG) of ictal fear were obtained in all patients. Three showed frontal onset, while the other two showed centrotemporal or occipital onsets. Two patients were seizure free at last follow-up, while seizures persisted in the other three. A patient with seizure onset during infancy had a favorable outcome, which was considered to be compatible with benign partial epilepsy with affective symptoms. Conclusion: Ictal fear is not always associated with a symptomatic cause or a poor seizure outcome. It is quite important to make a correct diagnosis of ictal fear as early as possible to optimize treatment.  相似文献   
1000.

Background

Mutations of POLR3A and POLR3B have been reported to cause several allelic hypomyelinating disorders, including hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome). Patients and methods: To clarify the difference in MRI between the two genotypes, we reviewed MRI in three patients with POLR3B mutations, and three with POLR3A mutations. Results: Though small cerebellar hemispheres and vermis are common MRI findings with both types of mutations, MRI in patients with POLR3B mutations revealed smaller cerebellar structures, especially vermis, than those in POLR3A mutations. MRI also showed milder hypomyelination in patients with POLR3B mutations than those with POLR3A mutations, which might explain milder clinical manifestations. Conclusions: MRI findings are distinct between patients with POLR3A and 3B mutations, and can provide important clues for the diagnosis, as these patients sometimes have no clinical symptoms suggesting 4H syndrome.  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