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   2786276篇
  免费   201495篇
  国内免费   4319篇
耳鼻咽喉   38200篇
儿科学   90641篇
妇产科学   74171篇
基础医学   412312篇
口腔科学   77281篇
临床医学   251687篇
内科学   538256篇
皮肤病学   61891篇
神经病学   217114篇
特种医学   103962篇
外国民族医学   552篇
外科学   417837篇
综合类   58091篇
现状与发展   12篇
一般理论   963篇
预防医学   215773篇
眼科学   65265篇
药学   208339篇
  32篇
中国医学   6237篇
肿瘤学   153474篇
  2021年   22291篇
  2019年   22734篇
  2018年   31475篇
  2017年   23759篇
  2016年   26635篇
  2015年   29978篇
  2014年   42196篇
  2013年   63352篇
  2012年   86707篇
  2011年   91835篇
  2010年   54662篇
  2009年   51666篇
  2008年   86320篇
  2007年   92012篇
  2006年   93079篇
  2005年   89758篇
  2004年   86185篇
  2003年   82704篇
  2002年   80329篇
  2001年   129451篇
  2000年   132644篇
  1999年   111233篇
  1998年   31846篇
  1997年   27813篇
  1996年   28207篇
  1995年   26725篇
  1994年   24595篇
  1993年   23131篇
  1992年   85979篇
  1991年   83926篇
  1990年   81723篇
  1989年   79105篇
  1988年   72747篇
  1987年   71255篇
  1986年   66886篇
  1985年   63823篇
  1984年   47423篇
  1983年   40282篇
  1982年   23656篇
  1979年   43584篇
  1978年   30963篇
  1977年   25854篇
  1976年   24754篇
  1975年   26636篇
  1974年   31881篇
  1973年   30436篇
  1972年   28515篇
  1971年   26937篇
  1970年   25104篇
  1969年   23735篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Biopharmaceutic comparison is achieved between commercialized capsules of vinburnine and drops dosage form intended for geriatric pharmacotherapy. Drug bioavailability of vinburnine seems saved, if not significantly increased by the new formulation, in spite of the very important, and well known interindividual variations of vincamine drug products. Only the absorption rate seems statistically increased by drops.  相似文献   
972.
Translated from Khimiko-farmatsevticheskii Zhurnal, Vol. 23, No. 5, pp. 540–549, May, 1989.  相似文献   
973.
974.
Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation   总被引:4,自引:0,他引:4  
The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.  相似文献   
975.
Two patients with a history of glaucoma and a propensity for uveitis developed ciliochoroidal effusions following Nd:YAG laser posterior capsulotomy. Both patients experienced a waxing and waning course with eventual resolution of symptoms after a steroid regimen. The ciliochoroidal effusions were presumed to be secondary to uveitis induced by the YAG laser surgery. The role of glaucoma, previous surgeries, and an open posterior capsule is uncertain but may have predisposed these patients to ciliochoroidal detachment. We advise caution in performing YAG posterior capsulotomy in patients with glaucoma and a known propensity for uveitis.  相似文献   
976.
St. Jude Medical valve replacement was performed in 1,039 patients; 320 had aortic (AVR), 543 mitral (MVR), and 176 had double valve replacement (DVR). There were 44(4.2%) early deaths. Follow-up extended in 995 patients from 10 to 130 months, with a cumulative period of 2,730 patients-years. The overall survival rates of AVR, MVR, and DVR patients at 10 years were 60.5%, 89.6%, 90.3% respectively. The linearized incidences of valve thrombosis, thromboembolism, anticoagulation-related hemorrhage, prosthetic valve endocarditis, and significant hemolysis were as follows: 0.11%/pt-yr, 1.33%/pt-yr, 0.04%/pt-yr, 0.18%/pt-yr, and 0.11%/pt-yr, respectively. There were no structural failure after 10 years follow-up. Reoperation (explant and re-replacement or suture repair) was required in 10 patients. Seven of them had periprosthetic leakage, 2 had valve thrombosis, and one underwent reoperation because of a technical error. Actuarially over 98% of patients were free of valve-related mortality at 10 years. St. Jude Medical valve is an excellent alternative for use in the surgical treatment of valvular heart disease.  相似文献   
977.
The first phase of data bank of hazard (DBH) of polymers has been developed and put into operation on the basis of CM-computers. DBH is a factographical computer-based system of data collection, storage and processing aimed at complex assessment of material and substance hazard. Systems approach to the analysis of material's characteristics serves as a methodological basis. DBH data base includes a set of input and output documents according to 5 types of biological hazards involving sanitary and chemical surveillance, fire hazard and thermodestruction, the data on material's microbiologic resistance, their electrifying and toxicohygienic characteristics. DUAMC-3 operational system, DUAMC. DBH software are included into the system of data banks of materials' technological properties.  相似文献   
978.
A sample of 110 consecutive first admission young schizophrenic patients treated between 1964 and 1967 was rediagnosed in 1981. Among 92 survivors, 27 could be labelled as paraphrenics. From information available at inception 97 variables were coded covering such areas as personality, previous disturbances, age and type of onset, and symptoms around admission. Sixty-three out of 97 variables were hypothesized to differentiate, at admission, future paraphrenics from the rest of the sample. Paraphrenics were found to have had less contact disturbance, better self-esteem, less neurotic symptoms in adolescence and childhood, and less complaints of unhappiness when growing up. They had more regressive and paranoid symptoms at admission, were older at onset of the disease, which was more acute, more often connected with precipitating events, and confusion. Certain non-regressive symptoms such as brooding, anhedonia and concentration difficulties were less common. A discriminant analysis yielded a proportion of correct predictions = 0.64 (p less than 0.05). The results are in accordance with the theory of more favourable energetic and organizational capacity in paranoid schizophrenics as compared with non-paranoids.  相似文献   
979.
In the cat synapses between vesicle containing profiles were observed in ventral and dorsolateral pontine nuclei. The presynaptic elements consisted of two types of axon terminals: axon terminals characterized by a population of small (38-40 nm) round synaptic vesicles (SSV) and axon terminals containing pleomorphic synaptic vesicles (PSV). The postsynaptic pale elements (PP) had pleomorphic vesicles and some features attributed to dendrites. In the dorsolateral pontine nucleus most of PP profiles took part in serial synapses, usually as an intermediate component, they were rarely observed in triads. On the basis of their electron microscopical appearance and synaptic relations they might be considered to represent a dendritic part of putative interneurons.  相似文献   
980.
A longitudinal perspective was employed to test the hypothesis that there is an increased risk of hospitalization among Antarctic winter-over personnel during the first year subsequent to this duty. Subjects were 327 enlisted Navy men who wintered-over between 1963 and 1974 and a control group of 2,396 enlisted men who volunteered and were accepted for winter-over duty but who did not winter-over. A 15-year period from 1965 to 1979 was established for follow-up. Follow-up of subjects subsequent to screening for Operation Deep Freeze was conducted in 6-month intervals for the first 4 years. Results indicated that the total rates of first hospitalization during the 6 months prior to Antarctic duty and the first 6 months in Antarctica among winter-over personnel were significantly lower than the rates for the control group. No significant difference in the rates of the two groups was observed for the 12 months subsequent to winter-over duty.  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