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   7672篇
  免费   689篇
  国内免费   63篇
耳鼻咽喉   67篇
儿科学   204篇
妇产科学   112篇
基础医学   673篇
口腔科学   139篇
临床医学   942篇
内科学   1842篇
皮肤病学   100篇
神经病学   649篇
特种医学   763篇
外科学   1135篇
综合类   124篇
一般理论   2篇
预防医学   693篇
眼科学   97篇
药学   383篇
  1篇
中国医学   4篇
肿瘤学   494篇
  2023年   65篇
  2022年   53篇
  2021年   109篇
  2020年   142篇
  2019年   92篇
  2018年   202篇
  2017年   141篇
  2016年   142篇
  2015年   155篇
  2014年   226篇
  2013年   305篇
  2012年   392篇
  2011年   356篇
  2010年   237篇
  2009年   255篇
  2008年   308篇
  2007年   344篇
  2006年   309篇
  2005年   288篇
  2004年   279篇
  2003年   218篇
  2002年   212篇
  2001年   208篇
  2000年   205篇
  1999年   185篇
  1998年   132篇
  1997年   131篇
  1996年   124篇
  1995年   110篇
  1994年   92篇
  1993年   96篇
  1992年   175篇
  1991年   146篇
  1990年   183篇
  1989年   199篇
  1988年   180篇
  1987年   160篇
  1986年   146篇
  1985年   117篇
  1984年   103篇
  1983年   79篇
  1982年   54篇
  1980年   50篇
  1979年   61篇
  1978年   65篇
  1977年   45篇
  1976年   48篇
  1974年   55篇
  1973年   48篇
  1972年   45篇
排序方式: 共有8424条查询结果,搜索用时 0 毫秒
101.
Background  The utility of routine ileoscopy as a component of screening colonoscopy is unclear. Many endoscopists believe that routine intubation of the terminal ileum is a requirement for a full-screening colonoscopy. The authors have hypothesized that routine ileal intubation during screening colonoscopy is of little diagnostic value. Methods  A retrospective analysis was performed using a prospectively maintained colonoscopy database of patients identified as undergoing a screening colonoscopy. All had undergone intubation of the terminal ileum at a tertiary referral center. Those who had undergone screening colonoscopy at the Mayo Clinic (Rochester, MN) were entered prospectively into a database. The study identified 6,408 patients who met the criteria of having terminal ileal intubation at the time of screening colonoscopy. The main outcome measured was abnormality of the terminal ileum at ileal intubation. Results  Ileoscopy showed grossly abnormal findings for only 1% of the patients, and pathologic abnormalities were identified for only 0.3% of all the patients. Conclusions  The findings support the conclusion that intubation of the terminal ileum should not be a required part of screening colonoscopy.  相似文献   
102.
This controlled trial was designed to investigate the influence of osteoporosis-related kyphosis (O-K) on falls. Twelve community-dwelling women with O-K (Cobb angle, 50–65° measured from spine radiographs) and 13 healthy women serving as controls were enrolled. Mean age of the O-K group was 76 years (±5.1), height 158 cm (±5), and weight 61 kg (±7.9), and mean age of the control group was 71 years (±4.6), height 161 cm (±3.8), and weight 66 kg (±11.7). Quantitative isometric strength data were collected. Gait was monitored during unobstructed level walking and during stepping over an obstacle of four different heights randomly assigned (2.5%, 5%, 10%, and 15% of the subjects height). Balance was objectively assessed with computerized dynamic posturography consisting of the sensory organization test. Back extensor strength, grip strength, and all lower extremity muscle groups were significantly weaker in the O-K group than the control group ( P <0.05), except right ankle plantar flexors ( P =0.09). There was a significant difference in the anteroposterior and mediolateral displacements and velocities. The O-K subjects had less anteroposterior displacement, greater mediolateral displacement, reduced anteroposterior velocity, and increased mediolateral velocity compared with controls for all conditions of unobstructed and obstructed level walking. Obstacle height had a significant effect on all center-of-mass variables. The O-K subjects had significantly greater balance abnormalities on computerized dynamic posturography than the control group ( P =0.002). Data show that thoracic hyperkyphosis on a background of reduced muscle strength plays an important role in increasing body sway, gait unsteadiness, and risk of falls in osteoporosis.  相似文献   
103.
104.
Skin, muscle, liver, and gonadal extracts of the Atlantic puffer, Spheroides maculatus were assayed for toxicity in white mice. Extracts were injected intraperitoneally and were administered in the amounts of 1 ml per 20 g of body weight. The LD50 of a composite skin extract, administered intraperitoneally in progressive doses per 20 g of body weight, was determined for white rats, white mice, chicks and frogs (Rana pipiens), while a LD50 of a composite muscle extract was determined for the pinfish, Lagodon rhomboides.  相似文献   
105.
PURPOSE: To ascertain the incidence of persistent strabismus in patients treated with plaque brachytherapy and its subsequent treatment. METHODS: A single center retrospective case note review of adult patients with persistent diplopia or strabismus following plaque brachytherapy for all types of intraocular tumors between 1996 and 2004. RESULTS: A total of 929 consecutive adults underwent plaque brachytherapy during the study period at a single center. Sixteen patients (1.7%) with treated uveal melanoma developed persistent diplopia or strabismus. In 11 patients (69%) the timing of onset was in the first year, in 2 (13%) in the second year, and one each (6% each) in years 5, 7, and 8. Two patients (13%) did not require any intervention. Fourteen patients (88%) required treatment: 7 (50%) were treated with prisms only, 3 (21%) underwent botulinum toxin (BTXA) injections, and 4 (29%) were treated with extraocular muscle surgery (3 required one operation and one required 2 procedures). CONCLUSIONS: The incidence of ocular motility disorders following plaque brachytherapy in our cohort was 1.7% over 8 years and we include this in the consent process for conservative treatment of intraocular tumors. Options for treatment for persistent diplopia or strabismus include prisms, botulinum toxin injection, or surgery.  相似文献   
106.
PURPOSE: To evaluate the long-term effect of vitrectomy with or without arteriovenous sheathotomy for macular edema secondary to branch retinal vein occlusion (BRVO). METHODS: The study was a prospective, randomized, comparative, interventional case series of 36 patients (36 eyes) who underwent pars plana vitrectomy with or without arteriovenous sheathotomy for macular edema due to BRVO of 相似文献   
107.
A prospective study was done of complications associated with 134 consecutive diagnostic spinal cord arteriograms in 96 patients (63 men and 33 women aged 17-78 years). Patients were examined for either arteriovenous malformation (n = 88) or tumor (n = 8), as indicated by myelography. Among the complications, 11 (8.2%) were local, five (3.7%) were systemic nonneurologic, and three (2.2%) were neurologic (two were associated with full recovery in less than 24 hours, and one was associated with full recovery in less than 1 week). No specific clinical or technical factors were significantly associated with the development of neurologic complications. Details of the clinical profile, angiographic technique, and pathologic findings for each patient were recorded and analyzed with respect to the potential risk for arteriographic complications. Diagnostic spinal cord arteriography had an acceptable risk within the range of other neuroangiographic diagnostic procedures.  相似文献   
108.
109.
110.
Forty-nine patients with primary myelodysplastic syndromes (MDS) were subclassified according to French-American-British (FAB) Cooperative Group criteria. Eight patients had acquired idiopathic sideroblastic anemia (AISA), ten had chronic myelomonocytic leukemia (CMMoL), 14 had refractory anemia (RA), nine had refractory anemia with excess blasts (RAEB), and five had refractory anemia with excess blasts in transformation (RAEB-T); three patients could not be subclassified. The actuarial median survival for patients with AISA or with RA had not been reached at 60 months of follow-up. The median survival times for patients with CMMoL, RAEB, and RAEB-T were 25, 21, and 16 months, respectively. The percentages of patients with each subtype who developed ANLL were none in AISA, 20% in CMMoL, 7% in RA, 56% in RAEB, and 40% in RAEB-T. Patients with CMMoL had a poor prognosis independent of transformation to acute nonlymphocytic leukemia (ANLL), whereas patients with RAEB and RAEB-T had a high incidence of transformation and short survival times. Clonal chromosomal abnormalities were present in bone marrow cells from 19 patients at the time of diagnosis, and two others developed an abnormal karyotype at the time of leukemic transformation. The most frequent abnormalities, including initial and evolutionary changes, were trisomy 8 (9 patients), deletion of 5q (4 patients), and deletion of 20q (4 patients). The median survival times were 32 months for patients with an abnormal karyotype, and 48 months for those with a normal karyotype (P = 0.2). Specific chromosomal abnormalities were not associated with particular histologic subtypes; however, a high percentage of patients with RAEB and RAEB-T had an abnormal clone (89% and 80%, respectively). The percentages of patients with clonal abnormalities were 13% for AISA, 20% for CMMoL, and 29% for RA. The MDS transformed to ANLL in 42% of patients with an abnormal karyotype, compared to 10% of those with an initially normal karyotype (P less than .01). Among patients with RA, RAEB, and RAEB-T, the risk of leukemic transformation was confined to those with an abnormal karyotype (P less than .01). Thus, in the present study, morphology and karyotype combined were the best indicators of outcome in patients with MDS.  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