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   1285篇
  免费   93篇
  国内免费   2篇
耳鼻咽喉   3篇
儿科学   21篇
妇产科学   37篇
基础医学   92篇
口腔科学   24篇
临床医学   159篇
内科学   305篇
皮肤病学   42篇
神经病学   34篇
特种医学   115篇
外国民族医学   1篇
外科学   229篇
综合类   42篇
预防医学   71篇
眼科学   2篇
药学   70篇
中国医学   3篇
肿瘤学   130篇
  2022年   29篇
  2021年   31篇
  2020年   20篇
  2019年   23篇
  2018年   28篇
  2017年   21篇
  2016年   21篇
  2015年   22篇
  2014年   36篇
  2013年   49篇
  2012年   50篇
  2011年   52篇
  2010年   50篇
  2009年   58篇
  2008年   39篇
  2007年   36篇
  2006年   40篇
  2005年   27篇
  2004年   32篇
  2003年   36篇
  2002年   23篇
  2001年   18篇
  2000年   24篇
  1999年   23篇
  1998年   27篇
  1997年   17篇
  1996年   28篇
  1995年   25篇
  1994年   29篇
  1993年   32篇
  1992年   21篇
  1991年   10篇
  1990年   10篇
  1989年   22篇
  1988年   24篇
  1987年   17篇
  1986年   15篇
  1985年   22篇
  1984年   10篇
  1983年   15篇
  1982年   15篇
  1981年   16篇
  1980年   18篇
  1979年   28篇
  1978年   18篇
  1977年   12篇
  1976年   14篇
  1972年   15篇
  1971年   11篇
  1970年   11篇
排序方式: 共有1380条查询结果,搜索用时 15 毫秒
81.
BACKGROUND: In the present study, the authors consider the possible association between intimal-media thickness of the common carotid arteries and lower limb atherosclerosis, in a group of elderly patients; the authors also consider the presence of cardiovascular risk factors. METHODS: B-mode ultrasound measurement of the intimal-media thickness of the common carotid arteries was performed on 80 subjects. Lower limbs atherosclerosis was defined as the presence of intermittens claudicatio and/or ankle-arm index < 0.9. Baseline clinic examination and blood tests were performed in all subjects to consider the presence of cardiovascular risk factors. Linear regression analysis was used to assess the linear relationship between intimal-media thickness of the common carotid arteries and lower limb atherosclerosis. RESULTS: Linear regression analysis showed a statistical association between increased values of intimal-media thickness of the common carotid arteries and lower limb atherosclerosis. Sixty-four (80%) subjects presented one or more associated cardiovascular risk factors. CONCLUSIONS: The results of the the present study confirm that intimal-media thickness of the common carotid arteries is a marker for the identification of generalized atherosclerosis and may be useful for the identification of subjects, even at early stages, at risk of cardiovascular diseases.  相似文献   
82.
Mediastinal masses: alternative approaches to CT-guided needle biopsy   总被引:10,自引:1,他引:10  
Bressler  EL; Kirkham  JA 《Radiology》1994,191(2):391
  相似文献   
83.
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.  相似文献   
84.
85.
Intralesional (IL) vitamin D3 is an emerging treatment for cutaneous warts. However, its effectiveness and exact mechanism is not fully evaluated. We aimed to compare the efficacy and safety of IL purified protein derivative (PPD) and IL vitamin D3 in multiple warts and to investigate their systemic effect clinically and immunologically. Forty‐five patients with multiple extragenital warts were treated with IL‐PPD (22 patients) or IL vitamin D3 injection (23 patients) for a maximum of three sessions at 3 week intervals. Decrease in size and number of warts and adverse effects were evaluated. Serum interleukin‐12 (IL‐12) and interferon‐gamma (IFN‐γ) levels were measured before and 3 weeks after the last session. Higher clearance rates for all warts were observed with IL‐PPD compared to IL vitamin D (59.1% vs. 21.7% complete clearance, p < .001). Significant increase was found in both serum IL‐12 and IFN‐γ after PPD treatment (p = .034 and p = .04, respectively), but only IFN‐γ after vitamin D3 treatment (p = 0.02). Both IL vitamin D3 and PPD showed positive results in treatment of multiple warts. However, PPD showed higher clinical efficacy and more increase in both IL‐12 and IFN‐γ levels.  相似文献   
86.
Summary. Haemophilia A is the most common inherited X‐linked recessive bleeding disorder. The aim was to investigate the usefulness of two DNA markers in linkage analysis, one intragenic BCL1 affecting restriction site in intron 18, and is detected as restriction fragment length polymorphism (RFLP), and one extragenic variable number of tandem repeat (VNTR) locus DXS52 (St14) to formulate an informative and accurate carrier detection and prenatal diagnosis. The study included 46 families with at least one child affected with haemophilia A, and 30 unrelated normal females as control group. Polymerase chain reaction (PCR) and restriction enzyme analysis were used to study the polymorphism in BCL1, and long‐distance PCR for detection of VNTR (ST14) alleles. The incidence of BCL1 (+) allele was 74%, 72% and 60% in patients, mothers and control group, respectively. Expected heterozygosity for BCL1 was 40% in mothers of affected cases compared with 48% in the female control group. However, observed heterozygosity was found to be 48% in the mothers of affected cases, compared with 60% in the control group. Thus, 48% of the studied families are informative for this marker alone. Nine different alleles of VNTR (St14) were observed in mothers and six alleles in affected cases and six in the control group. The most prevalent alleles were 1300 bp (45.5% and 34%) and 700 bp (13.6% and 20%) in patients and their mothers, respectively. Observed heterozygosity in mothers was 41% compared with 43.3% in controls. The combined use of both BCL1 and St14 markers raised the informative rate to 63.6%. Carrier detection and prenatal diagnosis is possible in haemophilia A families using both DNA markers. We suggest screening haemophilic families first for BCL1 polymorphism followed by analysis of St14 locus.  相似文献   
87.
88.
Wiener  JI; Chako  AC; Merten  CW; Gross  S; Coffey  EL; Stein  HL 《Radiology》1986,160(2):299-305
We tested a variety of inversion-recovery (IR) and spin-echo (SE) sequences by imaging the breast masses of 22 patients before surgery and 23 tissue specimens with magnetic resonance (MR) imaging at 0.6 T to determine the most effective pulse sequences to evaluate breast disease. An SE pulse sequence using a long repetition time (TR) of 1,600 msec and a long echo time (TE) of 90 msec was found to be the most sensitive in depicting carcinoma in the excised tissue specimens, with all of the carcinomas (n = 15) demonstrating irregular areas of higher signal intensity (SI) than that of the adjacent fat. However, only five of 11 breast carcinomas present in the preoperative patients produced a higher SI than that produced by fat on the same T2-weighted sequence. Five of the remaining six carcinomas in the preoperative patients appeared as localized distortions of fibroductular architecture on both T2-weighted SE and IR sequences. In axillary tissue specimens, both metastatic carcinoma and hyperplastic lymph nodes produced a high SI on T2-weighted SE sequences. However, metastatic carcinoma had a significantly longer T2 relaxation time than did hyperplastic lymph nodes.  相似文献   
89.
90.
Adjuvant therapy of resected adenocarcinoma of the pancreas   总被引:5,自引:0,他引:5  
Seventy-two patients underwent resections of pancreatic carcinomas between 1981 and 1989 at the Hospital of the University of Pennsylvania and were evaluable for follow-up. There were three treatment groups as treatment policies evolved. Initially, patients were observed after surgery without adjuvant treatment (Group 1-33 patients). Beginning in 1984, patients were offered adjuvant radiation therapy postoperatively (Group 2-19 patients) and eight of these patients also received 5-FU as an IV bolus on the first 3 days of the first and fifth weeks of treatment. Twenty patients were treated with chemosensitized radiation therapy following surgery using 96-hour 5-FU infusions during the first and fifth weeks of treatment. There were four postoperative deaths, which are excluded from the analysis, and sites of failure could not be determined for five other patients. Among evaluable patients, local recurrences occurred in 85% of the patients in group 1, 55% of the patients in group 2, and 25% of the patients in group 3. The 2-year survival was 35% in group 1, 30% in group 2, and 43% in group 3. Patients with involved surgical margins had a poor survival; only 2 of these 16 patients survived longer than 18 months. Among patients with negative margins, the 2-year survival is 41% in group 1, 33% in group 2, and 59% in group 3. Although the number of patients is smaller, the 3-year survival is 22% in group 1, 11% in group 2, and 47% in group 3. Chemosensitized irradiation is well tolerated in these patients. The major challenge in this group of patients is nutritional maintenance. There was no other significant toxicity. The trend in these observations suggests that survival following pancreatic resection is substantially improved with the addition of adjuvant chemosensitized radiation therapy.  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