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   6546篇
  免费   308篇
  国内免费   21篇
耳鼻咽喉   54篇
儿科学   136篇
妇产科学   112篇
基础医学   842篇
口腔科学   117篇
临床医学   441篇
内科学   1767篇
皮肤病学   109篇
神经病学   450篇
特种医学   394篇
外科学   1055篇
综合类   18篇
预防医学   234篇
眼科学   119篇
药学   447篇
中国医学   8篇
肿瘤学   572篇
  2023年   31篇
  2022年   67篇
  2021年   112篇
  2020年   59篇
  2019年   79篇
  2018年   108篇
  2017年   85篇
  2016年   102篇
  2015年   110篇
  2014年   153篇
  2013年   183篇
  2012年   309篇
  2011年   310篇
  2010年   152篇
  2009年   182篇
  2008年   300篇
  2007年   309篇
  2006年   286篇
  2005年   306篇
  2004年   296篇
  2003年   251篇
  2002年   232篇
  2001年   275篇
  2000年   269篇
  1999年   227篇
  1998年   88篇
  1997年   60篇
  1996年   72篇
  1995年   50篇
  1994年   49篇
  1993年   32篇
  1992年   148篇
  1991年   155篇
  1990年   153篇
  1989年   153篇
  1988年   124篇
  1987年   118篇
  1986年   130篇
  1985年   93篇
  1984年   95篇
  1983年   72篇
  1982年   33篇
  1981年   28篇
  1979年   48篇
  1978年   31篇
  1977年   32篇
  1974年   33篇
  1971年   31篇
  1970年   40篇
  1969年   28篇
排序方式: 共有6875条查询结果,搜索用时 0 毫秒
91.
The ACOSOG Z0011 trial has resulted in the omission of axillary lymph node dissection (ALND) in early breast cancer patients with one or two metastatic sentinel lymph nodes (SLNs). There has been increasing interest in the necessity of intraoperative assessment of SLNs in patients treated based on the Z0011 criteria. We evaluated the utility of intraoperative assessment in these eligible patients. A total of 1396 patients were treated following the Z0011 criteria from April 2012 to December 2019. We examined the proportion and clinicopathological features of patients who underwent ALND due to three or more metastatic SLNs and the sensitivity of intraoperative assessment. Only 16 (1.1%) patients had three or more metastatic SLNs diagnosed by intraoperative assessment, and they immediately underwent ALND. Of the clinicopathological factors, high clinical tumor stage (p = 0.002) and high Ki-67 labeling index value (p = 0.056) were more likely to be associated with the presence of three or more metastatic SLNs. The major independent risk factor for three or more metastatic SLNs was high clinical tumor stage (OR 3.94 [95% CI 1.42–11.0]; p = 0.009). Intraoperative assessment had low sensitivity (70.5%) and a high false-negative rate (29.5%) in detecting SLN metastases. The main finding of our study was the small proportion of patients who required ALND due to three or more metastatic SLNs according to the Z0011 criteria. The Z0011 strategy enables intraoperative assessment of SLNs to be omitted in early breast cancer patients.  相似文献   
92.
Although systemic therapy is the standard treatment for metastatic prostate cancer, a randomized controlled trial showed radiotherapy to the prostate improved overall survival of metastatic prostate cancer patients with the low metastatic burden. Additionally, a randomized phase II trial showed that metastasis-directed therapy for oligo-recurrent prostate cancer improved androgen-deprivation therapy (ADT)-free survival. Therefore, administering radiotherapy to both prostate and metastatic regions might result in better outcomes. Thus, we report the treatment results of radiotherapy to both prostate and metastatic regions. Our institutional database was searched for patients who received radiotherapy to the prostate and metastatic regions. We summarized patient characteristics and treatment efficacy and performed statistical analysis to find possible prognostic factors. A total of 35 patients were included in this study. The median age was 66 years, and the median initial prostate-specific antigen (PSA) level was 32 ng/ml. The Gleason score was 7 in 10 patients, 8 in 13 patients, and 9 in 12 patients. The median radiotherapy dose was 72 Gy to the prostate and 50 Gy to the metastatic bone region. The 8-year overall survival, cause-specific survival, progression-free survival, and freedom from biochemical failure rate were 81, 85, 53, and 57%. Among the 35 patients, 12 were disease-free even after ADT was discontinued. In selected patients with metastatic prostate cancer, ADT and radiotherapy to the prostate and metastatic sites were effective. Patients with good response to ADT may benefit from radiotherapy to both prostate and metastatic regions.  相似文献   
93.
Temperature changes and their distribution induced by 13.56-MHz radiofrequency (RF) heating of agar phantom and porcine and rabbit liver were investigated. It was possible to produce selective local heating of approximately 50 degrees C in the RF field of 2 x 2 x 2 cm(3) of the pig or rabbit liver. Coagulation necrosis after heating became pronounced and the margin between the coagulated lesion and normal tissue became clearer with time. Within 1 week after RF heating at 50 degrees C for 20 min, the coagulated area was replaced selectively and totally by necrotic tissue.  相似文献   
94.
OBJECTIVE: The purpose of this study is to evaluate the correlation between the intranodular blood supply revealed by CT during intraarterial injection of contrast medium, mainly using helical CT, and the grade of malignancy of hepatocellular nodules associated with liver cirrhosis as classified by the International Working Party of the World Congress of Gastroenterology. SUBJECTS AND METHODS: We studied 201 histologically proven nodules (101 resected and 100 biopsied nodules), including 47 low-grade dysplastic nodules (low-DNs), 56 high-grade dysplastic nodules (high-DNs), 24 well-differentiated hepatocellular carcinomas (wd-HCCs), and 74 moderately or poorly differentiated HCCs (mp-HCCs), in 139 cirrhotic patients. Findings on CT during arterial portography (n = 201) and CT during hepatic arteriography (n = 74) were reviewed and compared with the histologic diagnosis. RESULTS: CT findings were classified into four types relative to the surrounding liver: type A (isodense), type B (slightly hypodense), type C (partially hypodense), and type D (markedly hypodense) on CT during arterial portography and type I (isodense), type II (hypodense), type III (partially hyperdense), and type IV (hyperdense) on CT during hepatic arteriography. On CT during arterial portography, the distributions of each type were low-DN (n = 47 [A, n = 36; B, n = 8; C, n = 3]), high-DN (n = 56 [A, n = 18; B, n = 20; C, n = 10; D, n = 8]), wd-HCC (n = 24; [B, n = 4; C, n = 13; D, n = 7]), and mp-HCC (n = 74 [D, n = 74]). On CT during hepatic arteriography, the distributions were low-DN (n = 26 [I, n = 18; II, n = 7; III, n = 1]), high-DN (n = 19 [I, n = 6; II, n = 7; III, n = 4; IV, n = 2]), wd-HCC (n = 15 [I, n = 1; III, n = 8; IV, n = 6]), and mp-HCC (n = 14 [IV, n = 14]). We found a statistically significant correlation between the four types and the grade of malignancy of these nodules. CONCLUSION: Findings on CT during arterial portography and CT during hepatic arteriography correlated positively with histologic grading when overlap in appearance between dysplastic nodules and HCCs occurred. The concept revealed in this study can apply to diagnoses made on the basis of Doppler sonography, dynamic CT, and MR imaging.  相似文献   
95.
We report three cases of pseudolesions caused by aberrant right gastric venous drainage (AGVD) in segment II/III of the liver as demonstrated on CT during arterial portography (CTAP). On CTAP, the lesions were seen as wedge-shaped perfusion defects, and on hepatic arteriography, AGVD directed to the area with the perfusion defect was visible in all three cases. When a perfusion defect is detected at the edge of segments II/III at CTAP, a pseudolesion caused by AGVD should be suspected.  相似文献   
96.
97.
By using the microdialysis technique, the concentration of noradrenaline (NA) in the dorsal horn during unilateral hindpaw inflammation was compared between rats receiving bilateral lesions of the locus coeruleus (LC) and non-operated control rats. Bilateral lesions of the LC were made using an anodal current one week before testing. Unilateral hindpaw inflammation was produced by a subcutaneous injection of carrageenan (6 mg in 0.15 ml saline). Under conditions of sodium pentobarbital anesthesia, the microdialysis probe was inserted into the dorsal horn either ipsilateral or contralateral to the site of inflammation. The NA concentration in the dialysate was measured by high-performance liquid chromatography with electrochemical detection. Prior to carrageenan injection, the NA level (baseline level) did not differ between the LC-lesioned and the non-operated groups. After carrageenan injection, in the non-operated rats, the NA level increased significantly compared to the baseline level only in the dorsal horn ipsilateral to the site of inflammation, but not in the dorsal horn contralateral to the site of inflammation. An increase of the NA level was not observed in the LC-lesioned rats and in rats receiving an injection of saline. The result suggests that unilateral hindpaw inflammation produces excitation of descending NA-containing neurons from the LC, resulting in an increase of the NA level in the dorsal horn ipsilateral to the site of inflammation.  相似文献   
98.
This study sought to assess the prevalence and symptomatology of comorbid obsessive-compulsive disorder (OCD) among Japanese subjects who met the DSM-III-R criteria for bulimia nervosa (BN). The Structured Clinical Interview for DSM-III-R Patient Version was used to distinguish 26 BN patients with concurrent OCD from 52 BN patients without OCD. Obsessive-compulsive symptoms in BN subjects with concurrent OCD were evaluated using the Japanese version of the Yale-Brown Obsessive-Compulsive Scale. There were no differences in the prevalence of concurrent OCD between BN subjects with and without a lifetime history of anorexia nervosa. Among BN subjects with concurrent OCD, symptoms related to symmetry and order were most frequently identified, followed by contamination and aggressive obsessions, and checking and cleaning/washing compulsions. Bulimia nervosa subjects with concurrent OCD were more likely than subjects without OCD to have more severe mood and core eating disorder psychopathology. Comorbid OCD is a common phenomenon in Japanese bulimics (33%) similar to that suggested in BN subjects in the Western countries. Obsessive-compulsive symptoms related to symmetry and order were most frequently observed in BN subjects with concurrent OCD, which was a similar finding to that reported among restricting anorexic subjects.  相似文献   
99.
PURPOSE: The prognosis of metastatic renal cell carcinoma is extremely poor. In this type of metastatic tumor cytoreductive surgery of the primary tumor is often performed to confirm the histological type or improve the response to immunotherapy with agents such as interferon or interleukin-2. However, the timing and impact of cytoreductive surgery on the success of immunotherapy require further study. We determined the type of metastatic renal cell carcinoma for which cytoreductive surgery is beneficial. MATERIALS AND METHODS: We retrospectively reviewed the records of 58 patients in whom metastatic renal cell carcinoma was diagnosed at our hospital between 1986 and 1997. Three patients were excluded from study because they were judged to be poor candidates for surgery due to poor performance status. Of the remaining 55 patients 34 consented to cytoreductive surgery of the primary tumor and 21 did not. All except 1 patient were treated with interferon therapy. We evaluated the association of pretreatment serum C-reactive protein and the effect of surgery. RESULTS: We noted no significant difference in age at diagnosis, pretreatment serum immunosuppressive acidic protein, site of metastasis or performance status in 34 patients who underwent cytoreductive surgery and 21 who did not. Of the 21 patients in whom pretreatment serum C-reactive protein was within normal limits (less than 1.0 ng./ml.) no significant difference in disease specific survival was observed in those who did and did not undergo surgery (p = 0.4133). On the other hand, of 34 patients in whom pretreatment serum C-reactive protein was elevated (1.0 ng./ml. or greater) the prognosis was significantly better in those who did versus those who did not undergo surgery (p = 0.0054). Particularly the prognosis in patients in whom postoperative nadir C-reactive protein decreased to within normal limits was markedly better than in those in whom it remained elevated (p = 0.0025). CONCLUSIONS: Our study suggests that cytoreductive surgery is beneficial to patients in whom pretreatment serum C-reactive protein is elevated. Particularly, those in whom serum C-reactive protein decreases to within normal limits may expect longer survival when surgery is combined with postoperative immunotherapy. Currently to our knowledge the prognostic factor that predicts postoperative nadir C-reactive protein has not been identified, indicating that cytoreductive surgery of the primary tumor should be performed in patients with elevated pretreatment C-reactive protein and as performance status permits.  相似文献   
100.
BACKGROUND: A randomized, controlled clinical trial was conducted in 1991 to compare an intravenous megadose of methylprednisolone with a control drug (mecobalamin) for treating acute idiopathic optic neuritis. CASES: Sixty-six cases from 22 clinical centers throughout Japan were examined to evaluate the treatment on visual function parameters, such as visual acuity, visual field, color vision, contrast sensitivity, and critical flicker frequency. OBSERVATIONS: The methylprednisolone pulse treatment group showed faster recovery of visual function, particularly the visual acuity at 1 week (P<.05), Humphrey field analyzer mean deviation at 3 weeks (P<.05), and color vision at 1 week (P<.05). Recovery of contrast sensitivity at several different spatial frequencies was significant in the pulse treatment group at 1 (P<.01), 2 (P<.05), and 4 weeks (P<.05) after the start of treatment. Visual function test results at 12 weeks and 1 year were essentially the same in the two treatment groups. Side effects appeared more frequently in the pulse treatment group than in the control (P<.05). CONCLUSIONS: Pulse treatment does not appear effective for idiopathic optic neuritis even though visual function in the pulse treatment group of this trial recovered more quickly during the initial phase compared to the controls. More effective and specific treatment should be established for optic neuritis.  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