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   1894篇
  免费   180篇
  国内免费   10篇
耳鼻咽喉   24篇
儿科学   100篇
妇产科学   59篇
基础医学   154篇
口腔科学   42篇
临床医学   197篇
内科学   471篇
皮肤病学   11篇
神经病学   109篇
特种医学   198篇
外科学   408篇
综合类   42篇
一般理论   1篇
预防医学   67篇
眼科学   5篇
药学   79篇
中国医学   5篇
肿瘤学   112篇
  2022年   8篇
  2021年   35篇
  2020年   13篇
  2019年   24篇
  2018年   57篇
  2017年   57篇
  2016年   54篇
  2015年   51篇
  2014年   59篇
  2013年   88篇
  2012年   82篇
  2011年   84篇
  2010年   98篇
  2009年   85篇
  2008年   68篇
  2007年   60篇
  2006年   70篇
  2005年   54篇
  2004年   60篇
  2003年   58篇
  2002年   57篇
  2001年   50篇
  2000年   53篇
  1999年   42篇
  1998年   63篇
  1997年   60篇
  1996年   57篇
  1995年   56篇
  1994年   29篇
  1993年   40篇
  1992年   27篇
  1991年   24篇
  1990年   30篇
  1989年   21篇
  1988年   31篇
  1987年   24篇
  1986年   22篇
  1985年   18篇
  1984年   13篇
  1983年   17篇
  1982年   7篇
  1981年   24篇
  1980年   11篇
  1979年   14篇
  1977年   20篇
  1976年   10篇
  1975年   12篇
  1967年   6篇
  1964年   6篇
  1960年   6篇
排序方式: 共有2084条查询结果,搜索用时 27 毫秒
1.
2.
Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml -1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml -1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-2 week-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.  相似文献   
3.
The sp act of galactose-1-phosphate uridyltransferase has been measured in individual regions of adult rat brain to see if site-specific differences in enzyme activity can aid in the understanding of brain abnormalities observed in well-treated galactosemic patients. The sp act in the cerebellum, brain stem, and midbrain were higher than in the cortex, hippocampus, and striatum. Activity in the cerebellum was 2-fold greater than that found in the cortex. Steady state levels of mRNA of the enzyme in the cerebellum were twice that of the cortex corresponding to the ratio of enzyme sp act in the two regions. Measurement of the kinetic parameters in tissue from the cerebellum and cortex revealed that the regional specificity in enzyme activity observed in the brain represents differences in the Vmax. Inhibition of the enzyme by uridine and uridine triphosphate was essentially the same for all regions and was not influenced by the 2-fold differences observed in the levels of enzyme. Inhibition by uridine was significantly greater than that for uridine triphosphate.  相似文献   
4.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.  相似文献   
5.
OBJECTIVES: To determine if experienced clinical educators (CEs) can improve their teaching by incorporating 4 literature-based teaching methods into their instruction. METHODS: We trained 7 experienced CEs on the teaching methods during a monthly faculty development program. Each CE recorded use of these methods during 10 months on a personal digital assistant. We compared the CEs' teaching evaluations with those of nonparticipating faculty by analysis of variance at baseline, during the study period, and for 1 year after the study. RESULTS: Reported use of 2 teaching methods (priming and feedback) increased significantly over use at baseline; use of 2 other methods (teaching in the patient's presence and 1-2 focal teaching points) remained constant. Scores on the CEs' teaching evaluations were significantly higher during the study period on 1 item, whereas the comparison group showed no changes. The changes persisted during the follow-up period. CEs reported that the teaching methods focused the learner and teacher, making subsequent encounters more productive. They also found that the act of entering data daily prompted them to reflect on their teaching. CONCLUSIONS: Experienced teachers can be persuaded to incorporate new methods into their daily teaching. Reflection on teaching is enhanced with group support and daily reminders. With these interventions, teaching effectiveness of these experienced educators improved.  相似文献   
6.
7.
Between 1977 and 1987, 519 patients underwent operation for rectal carcinoma. Sixty-three patients underwent intersphincteric resection with direct coloanal anastomosis (CAA), and 77 had an abdominoperineal resection (APR). Curative surgery was achieved in 57 and 65 patients, respectively. Both groups were comparable regarding age, stage of tumors, and localization of tumors. During the mean period of 6.7 years (range: 3 to 13.6 years), all patients were examined according to a predefined follow-up plan. From those patients with curative surgery, 11% presented with pelvic recurrence and 33% with distant metastases after coloanal anastomosis; the rates of recurrence and distant metastases after APR were 17% and 35%, respectively. The corrected 5-year survival rates were 62% following CAA and 53% following APR. Eighty-five percent of the patients with CAA reported good functional results regarding anal continence. Our study demonstrates that the intersphincteric resection with CAA is a valuable surgical technique for rectal carcinoma with the benefit of preservation of continence. It is suitable for neoplasms with high- and medium-grade differentiation (G1 to G2) and a localization that allows a minimum distal clearence of 3 cm.  相似文献   
8.
Bottomley  PA; Lee  Y; Weiss  RG 《Radiology》1997,204(2):403
  相似文献   
9.
10.
目的研究臂丛神经损伤膈神经移位术对青壮年患者早期呼吸功能的影响.方法对16例接受膈神经移位治疗的患者,在术前、术后(10 d)进行肺功能指标的比较,同时定期进行门诊随访,观察呼吸系统自觉症状程度.结果13例术后出现了不同程度的供氧不足症状,16例全部出现一侧膈肌抬高,术后第10天肺活量(VC)、肺活量预计值百分数(VC%)分别比术前减少37.98%和26.88%,两者差异有统计学意义(tvc=11.532、tvc%=0,P<0.01).其它项目如残气量(RV)较术前轻度下降,肺总量(TLC)下降值达到术前肺总量的36.49%,残气量/肺总量比值(RV/TLC%)较术前上升了4.75%,上述各指标的差值均有统计学意义.1 s用力呼气量/用力肺活量比值(FEV1/FVC)和术前比基本无改变,但其差值有统计学意义.膈神经移位右侧(10例)与左侧(6例)术前、术后肺活量比较差异有统计学意义.术后随访8个月~2年,所有患者均无明显呼吸困难和胸闷等症状.结论膈神经移位术后对青壮年患者肺容量有较大的丧失,肺通气功能减弱和小气道阻力增加,但其丧失程度在机体自身代偿耐受范围内,不会导致急剧发生的严重呼吸功能障碍.建议对右侧臂丛神经根性损伤的患者,术前进行严格的肺、心功能检查,避免发生较为严重的并发症.  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