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   1218125篇
  免费   86276篇
  国内免费   5925篇
耳鼻咽喉   17121篇
儿科学   31198篇
妇产科学   30962篇
基础医学   173709篇
口腔科学   36764篇
临床医学   106320篇
内科学   238196篇
皮肤病学   25570篇
神经病学   92714篇
特种医学   46919篇
外国民族医学   172篇
外科学   193845篇
综合类   31030篇
现状与发展   8篇
一般理论   289篇
预防医学   76611篇
眼科学   29380篇
药学   96776篇
  31篇
中国医学   5471篇
肿瘤学   77240篇
  2021年   9137篇
  2019年   9090篇
  2018年   13399篇
  2017年   10596篇
  2016年   11409篇
  2015年   13209篇
  2014年   17958篇
  2013年   24766篇
  2012年   33838篇
  2011年   35371篇
  2010年   21069篇
  2009年   19914篇
  2008年   33142篇
  2007年   35188篇
  2006年   35524篇
  2005年   33805篇
  2004年   32194篇
  2003年   30937篇
  2002年   30104篇
  2001年   72911篇
  2000年   74686篇
  1999年   62078篇
  1998年   14860篇
  1997年   12949篇
  1996年   12479篇
  1995年   11662篇
  1994年   10625篇
  1993年   9774篇
  1992年   45552篇
  1991年   43188篇
  1990年   41473篇
  1989年   40571篇
  1988年   36793篇
  1987年   35827篇
  1986年   33350篇
  1985年   31619篇
  1984年   22323篇
  1983年   18780篇
  1982年   9694篇
  1979年   19506篇
  1978年   12995篇
  1977年   11174篇
  1976年   9546篇
  1975年   10523篇
  1974年   12713篇
  1973年   11962篇
  1972年   11403篇
  1971年   10889篇
  1970年   10255篇
  1969年   9705篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Concentrations of the vitamins B1, B2, B6, B12, C, folic acid,A, E and ß-carotene were determined in blood and 24-hdialysate in 44 CAPD patients. Twenty-five of these patientswere studied during chronic treatment (mean 313 days, range60–1034 days). Nineteen patients were studied during training.In a longitudinal study, 11 patients were analysed again after77–507 (mean 238) days. In both patient groups a considerable portion of patients (11%–64%)had blood concentrations indicative of a deficiency of the vitaminsB1, B6, C and folic acid. The average concentrations of thesevitamins were normal in both groups. The only abnormal findingwas the mean EGOT activity being deficient in patients on chronictreatment. Mean concentrations of vitamin A were above normalin both groups. In the longitudinal study a significant increaseof vitamin B2 and a decrease of vitamin B6 in blood was found. When compared to 24-h excretion in normal urine, loss with 24-hdialysate was low for vitamin B1, normal to relatively highfor vitamin B2 and B6, but extremely high for vitamin C andfolic acid. The vitamins B12, A, E and carotenoids were hardlydetectable in the dialysate. In ten other patients the effect of daily supplementation with2 mg vitamin B6, 100mg vitamin C and 400 µg folic acidwas analysed during a 16-week period. In all patients a significantincrease in blood concentrations was obtained. It is concludedthat these dosages were sufficient to maintain a normal statusof these vitamins in CAPD patients.  相似文献   
982.
Proportionate cancer mortality was analyzed among white male carpet and textile workers in five northwest Georgia counties for the years 1970-1984. Compared with other Georgians, carpet and textile workers had higher proportions of lymphocytic leukemia (proportionate cancer mortality ratio [PCMR] = 2.9; 95% CI = 1.4-5.4]) and testicular cancer (PCMR = 3.2; 95% CI = 1.0-7.5). The excess mortality from lymphocytic leukemia was even higher when the analysis was limited to workers deemed most likely to work directly in production areas (PCMR = 4.2; 95% CI = 1.7-8.7). Further studies are needed to determine if the observed excesses are the result of workplace exposures.  相似文献   
983.
The patient, a 72-year-old female, was admitted with an 11-year history of progressive dysesthesia in the left leg. Neurological findings on admission revealed weakness in the bilateral legs, hyperreflexia of left leg, hypalgesia and hypesthesia under the Th 8 level, and urinary incontinence. Plain lumber X-ray showed enlargement of the intervertebral foramen of L 1/2. Myelography disclosed block age at the level of Th 9 and filling defect at the level of Th 10/11 and L1/2. CT myelography revealed a cord swelling and partially exophytic tumor from Th 8 to Th 9, another tumor located posterior-laterally at the level of Th 11, and another tumor located extra and intradural at the level of L1/2. Laminectomy was performed from Th 8 to L 3. A tumor of the Th 9 was located intramedullary, another tumor of the Th 11 was located intradural extramedullary, and another tumor of the L1/2 was located in the epidural space (so-called dumb-bell type tumor). These tumors were removed completely except the extra-canal part of L1/2 tumor. Histopathological examination revealed typical Antoni type A schwannoma in all tumors. This case was considered multiple neurinomas of the spine in which tumors were located in three separate anatomical sites, intramedullary, intradural extramedullary, and epidural sites. This patient did not show café-au-lait spot, and neurofibroma in her body. The authors considered the patient might be a case of central neurofibromatosis. The authors stressed that multiple neurinomas of the spine is not rare, so careful study of the whole spine is necessary including its intramedullar space.  相似文献   
984.
Mortality of cadmium-exposed workers. A five-year update   总被引:6,自引:0,他引:6  
A cohort mortality study of cadmium-exposed workers initially followed to the end of 1979 has been updated for a further five years. The update has confirmed the findings of the original study with a significant excess risk from bronchitis related to intensity of exposure, although over the five-year period the excess mortality was no longer significant, a finding suggesting that the risk from bronchitis may now be declining in this cohort. In contrast, there is now a stronger indication of a excess risk from lung cancer related to intensity of exposure, significant for both the total and the five-year periods. There was again no increased risk from prostatic cancer, and from this and other studies it appears unlikely that cadmium, in the concentrations encountered in this and other recent studies, acts as a prostatic carcinogen. As in the initial study, there was no significant excess risk from hypertensive disease, nor any suggestion of an increased risk from cerebrovascular or renal disease.  相似文献   
985.
986.
Two patients with pigmented paravenous chorioretinal atrophy are presented. Both patients had chorioretinal atrophy with pigment clusters located in the paravenous areas, and one of the patients had macular affection. This patient had exotropia and juvenile cataract, the other patient had senile cataract. Electroretinography showed decreased, but not totally extinguished potentials. Automatic and manual perimetry revealed relative and absolute scotomas corresponding to the atrophic paravenous areas. To our knowledge this is only the sixth report of pigmented paravenous chorioretinal atrophy with macular affection.  相似文献   
987.
988.
989.
990.
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