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   15892篇
  免费   734篇
  国内免费   164篇
耳鼻咽喉   182篇
儿科学   260篇
妇产科学   125篇
基础医学   1902篇
口腔科学   368篇
临床医学   1045篇
内科学   4218篇
皮肤病学   305篇
神经病学   1264篇
特种医学   619篇
外科学   2893篇
综合类   55篇
预防医学   468篇
眼科学   163篇
药学   1047篇
中国医学   18篇
肿瘤学   1858篇
  2023年   103篇
  2022年   166篇
  2021年   356篇
  2020年   214篇
  2019年   261篇
  2018年   330篇
  2017年   268篇
  2016年   326篇
  2015年   336篇
  2014年   461篇
  2013年   564篇
  2012年   906篇
  2011年   931篇
  2010年   519篇
  2009年   452篇
  2008年   843篇
  2007年   878篇
  2006年   909篇
  2005年   944篇
  2004年   938篇
  2003年   878篇
  2002年   902篇
  2001年   374篇
  2000年   356篇
  1999年   430篇
  1998年   262篇
  1997年   191篇
  1996年   197篇
  1995年   153篇
  1994年   142篇
  1993年   125篇
  1992年   218篇
  1991年   218篇
  1990年   172篇
  1989年   191篇
  1988年   204篇
  1987年   152篇
  1986年   142篇
  1985年   137篇
  1984年   88篇
  1983年   57篇
  1982年   37篇
  1981年   38篇
  1980年   27篇
  1979年   66篇
  1978年   52篇
  1977年   31篇
  1975年   36篇
  1971年   22篇
  1969年   24篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
992.
A 50-year-old woman was admitted because of high fever and fatigue. Proteinuria, hematuria, and elevated BUN (47.8mg/dl) and creatinine (3.4mg/dl) suggested rapidly progressive glomerulonephritis. The serological study revealed all negative results for rheumatoid factor, antinuclear antibody, serum cryoglobulins, MPO-ANCA, PR3-ANCA, and anti-streptolysin O. Antiglomerular basement membrane (GBM) antibody, as assessed by ELISA, was 11EU (normal, <10). Kidney biopsy on the eighth hospital day demonstrated pauci-immune-type crescentic glomerulonephritis without ANCA. Methylprednisolone pulse therapy (500mg/day, 3 days) and 45mg/day prednisolone orally were started. At 3 weeks after kidney biopsy, the anti-GBM antibody value increased from 11EU/ml to 116EU/ml, and MPO and PR3-ANCA were still negative. HLA type was DR8 and DR 15(2), with a genotype of HLA-DRB1*08021 and HLA-DRB1*15011. The present case suggests that HLA-DR15 plays an important role on antibody production against alpha 3(IV) NC1 autoantigen after severe nephritis or tissue damage.  相似文献   
993.
A patient with posthypoxic cortical action myoclonus was studied using polygraphic EEG-EMG recording techniques and transcranial magnetic stimulation. The myoclonic jerks were not stimulus-sensitive, and were not associated with enhancement of the somatosensory evoked potential (SEP). The most prominent electrophysiological finding was that rhythmic EMG activity was produced when the patient attempted rapid voluntary movement. EEG-EMG polygraph indicated that the rhythmic EMG activity was preceded by rhythmic activity in the EEG recorded overlying the contralateral central region. The frequency of both EEG and EMG activity was the same (approximately 50 Hz). Treatment using a combination of clonazepam, carbamazepine and primidone diminished the action myoclonus, concomitant with the disappearance of the rhythmic EEG and EMG activity. In the sensorimotor cortex of the normal monkey and humans, oscillatory activity ranging between 20-50 Hz has been recorded in the local field potential. Our findings suggest that cortical hyperoscillation may produce this characteristic rhythmic EEG and EMG activity and may, in turn, be related to cortical action myoclonus.  相似文献   
994.
BACKGROUND: Although laboratory experiments suggest protective effects of green tea against colorectal cancer, few prospective cohort studies have been conducted.METHODS: We conducted a pooled analysis of two prospective cohort studies among residents in Miyagi Prefecture in rural northern Japan. The first study started in 1984 and included 26,311 subjects. The second study started in 1990 and included 39,604 subjects. The subjects responded to a self-administered questionnaire including an item on green tea consumption. With 7 to 9 years of follow-up, 305 colon and 211 rectal cancers were identified in the two cohorts through record linkage to a regional cancer registry. We used Cox regression to estimate the hazard ratio (HR) of colorectal cancer according to the consumption of green tea with adjustment for potential confounders, and pooled the estimates obtained from each cohort by general variance-based method.RESULTS: Multivariate pooled HRs for colon cancer associated with drinking 1-2, 3-4, and 5 or more cups of green tea per day, as compared with less than 1 cup per day, were 1.06 (95% confidence interval [CI]=0.74-1.52), 1.10 (0.78-1.55), 0.97 (0.70-1.35), respectively (trend p=0.81). Corresponding HRs for rectal cancer were 0.85 (95% CI=0.56-1.29), 0.70 (0.45-1.08), 0.85 (0.58-1.23), respectively (trend p=0.31).CONCLUSIONS: Consumption of green tea was not associated with lower risk of colorectal cancer.  相似文献   
995.
This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion.  相似文献   
996.
997.
The aim of this retrospective study was to evaluate the effectiveness of low-dose cisplatin and 5-fluorouracil (low-dose FP) as an adjuvant chemoradiotherapy for resected advanced squamous cell carcinoma of the esophagus. From 1994 to 1999, 57 patients who showed an invasion of the tumor over the muscularis propria (T2-T4), regional lymph node metastasis (N1), and no distant metastasis (M0) were enrolled in this analysis. Postoperative chemoradiotherapy (CRT group) was performed on 14 of the patients, and they were compared to the patients who underwent surgery alone (S group) using the matched pair algorithm. In the CRT group, chemotherapy of low-dose FP was combined with concurrent radiotherapy after the esophagectomy. A side-effect of severe dysphagia (NCI-CTC Grade 3) was observed in 4 patients (28.6%) and leukocytopenia in 1 patient (7.1%) among the CRT group. The overall survival rate of the CRT group and matched S group were 35.7% and 28.5% at 5 years, respectively, with no significant difference. In the CRT group, 7 of 14 patients (50%) had a recurrence. The recurrence rate was slightly lower than in the S group (57%), with no significant difference. This combined chemoradiotherapy using low-dose FP did not improve the prognosis of patients with resected advanced esophageal carcinoma.  相似文献   
998.
Purpose We compared the clinicopathologic features affecting outcome after surgery for hepatocellular carcinoma (HCC) between patients with concurrent and previous chronic hepatitis B.Methods Group A consisted of 58 patients with concurrent chronic hepatitis B, defined by seropositivity for the hepatitis B surface antigen (HBsAg), and group B consisted of 18 patients whose HCC was detected after disappearance of the HBsAg. We assessed the influence of various characteristics on outcome.Results The mean age and percentage of patients suffering from alcohol abuse or diabetes mellitus were significantly greater in group B than in group A, whereas histologic hepatitis activity, hepatic fibrosis, and alanine aminotransferase activity were significantly lower in group B than in group A. The tumor-free survival rates were similar between the two groups, but the risk factors of recurrence differed. In group A, relative youth, high aspartate aminotransferase activity, low platelet count, multiple tumors, large tumor size, portal invasion, cirrhosis, nonanatomic resection, and positive surgical margin were risk factors. In group B, large tumor size and poor differentiation were risk factors.Conclusion Hepatitis B status, tumor factors, and the type of operation affected cancer recurrence after surgery for HCC in patients with concurrent chronic HBV, as opposed to only tumor factors in patients with previous chronic hepatitis B.  相似文献   
999.
Iwai Y  Yamanaka K  Yoshimura M 《Surgical neurology》2005,64(5):406-10; discussion 410
BACKGROUND: We evaluated the efficacy of gamma knife radiosurgery for cavernous sinus metastases and invasion. METHOD: We treated and followed up 21 patients with cavernous sinus metastases and invasion using gamma knife radiosurgery. Nine of these patients had nasopharyngeal cancer, and 12 had distant metastases from other cancers. The volume of tumors ranged from 2.9 to 50.0 (median 9.9) mL. and the radiation dose to the tumor margin was 10 to 21 (median 14) Gy. RESULTS: The median follow-up period was 9 months. Clinical symptoms were improved in 48% of the patients after treatment, and tumor growth control was obtained in 67% of the patients at their final follow-up. The actual 1- and 2-year tumor growth control rates were 68% and 43%, respectively. The mean survival time was 13 months. No patient had radiation injury. CONCLUSION: Gamma knife radiosurgery is a very useful therapeutic option for the treatment of cavernous sinus metastases and invasion, either as initial treatment or as an adjunct treatment for recurrences even in preirradiated patients.  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