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   1073228篇
  免费   73271篇
  国内免费   1360篇
耳鼻咽喉   15014篇
儿科学   34597篇
妇产科学   28648篇
基础医学   153443篇
口腔科学   29664篇
临床医学   94906篇
内科学   203550篇
皮肤病学   24392篇
神经病学   81470篇
特种医学   42967篇
外国民族医学   201篇
外科学   163103篇
综合类   21691篇
现状与发展   1篇
一般理论   265篇
预防医学   74541篇
眼科学   24481篇
药学   86126篇
  7篇
中国医学   2806篇
肿瘤学   65986篇
  2019年   7768篇
  2018年   11302篇
  2017年   8915篇
  2016年   10110篇
  2015年   11270篇
  2014年   15283篇
  2013年   22221篇
  2012年   30587篇
  2011年   32318篇
  2010年   18972篇
  2009年   17835篇
  2008年   29981篇
  2007年   32092篇
  2006年   32734篇
  2005年   31071篇
  2004年   29742篇
  2003年   28571篇
  2002年   27555篇
  2001年   60044篇
  2000年   61500篇
  1999年   50950篇
  1998年   12457篇
  1997年   11014篇
  1996年   11019篇
  1995年   10326篇
  1994年   9345篇
  1993年   8859篇
  1992年   37810篇
  1991年   36291篇
  1990年   35755篇
  1989年   34291篇
  1988年   30875篇
  1987年   29994篇
  1986年   28231篇
  1985年   26453篇
  1984年   19187篇
  1983年   16116篇
  1982年   8828篇
  1979年   17036篇
  1978年   11414篇
  1977年   10236篇
  1976年   8841篇
  1975年   10071篇
  1974年   11660篇
  1973年   11280篇
  1972年   10762篇
  1971年   10101篇
  1970年   9260篇
  1969年   8944篇
  1968年   7919篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
991.
A case of malignant fibrous histiocytoma of the mediastinum presenting with unusual features of fever and leucocytosis is reported. This is the youngest patient reported in the literature who had this tumour in the mediastinum.  相似文献   
992.
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   
993.
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   
994.
Biologic distribution data in the rat were obtained for the alpha-1 adrenoceptor imaging agent (+/-) 2-[beta-(iodo-4-hydroxyphenyl)ethylaminomethyl]tetralone (HEAT) labeled with [125I]. The major excretory routes were through the liver (67%) and the kidney (33%). Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads, and red bone marrow were calculated for the human using the physical decay data for [123I]. The critical organ was found to be the lower large intestine, receiving 1.1 rad per mCi of [123I]HEAT administered. The total-body dose was found to be 58 mrad per mCi.  相似文献   
995.
996.
This issue comprises selected topics of CCK peptides. CCK peptides are linear peptides and were found within and outside the CNS. There is growing evidence that CCK peptides play a physiological role in food intake, contraction of gallbladder and regulation of motility of the gastrointestinal system. New aspects of the CCK research are concentrated on interaction with other transmitter systems especially with the dopamine and opioid system. The therapeutic action to improve clinical symptoms in human is unclear up to new. World-wide, the interest is focused to determine the potential of CCK peptides as an antipsychotic agent by controlled clinical studies.  相似文献   
997.
998.
We reviewed all 341 cases of abdominal tuberculosis reported in Canada between 1970 and 1981. Over the study period abdominal tuberculosis accounted for a stable proportion (0.8%) of all reported cases of tuberculosis in Canada. Its incidence declined steadily. It was more common in women, in native Indians and in people born in Asia. Detailed records of the 55 cases reported to Statistics Canada from British Columbia and of an additional 31 cases not reported to Statistics Canada (usually because they involved concomitant disease elsewhere, notably the lungs) were studied. Five of the 55 cases reported to Statistics Canada had been reported incorrectly. Of the 81 cases in British Columbia 51% involved peritonitis, 21% ileocecal disease, 20% anorectal disease, 10% mesenteric lymphadenitis, 1% disease of the sigmoid colon and 1% disease of the liver. The rate of bacteriologic confirmation was low (51%).  相似文献   
999.
1000.
K Ando 《Gan no rinsho》1987,33(13):1679-1683
Basic mechanisms of radioprotection and clinical applicability of radioprotectors for low-and high-LET radiotherapy were reviewed and discussed here. Chemical radioprotectors are able to inhibit indirect radiation damage, to repair direct and indirect damage once they occur, and to facilitate the recovery of damaged cells on depleted cell populations. The vast majority of radioprotective agents that have been developed and tested are the aminothiols. WR-2721 or ethiofos represents a significant improvement in effectiveness, potency and reduction of toxicity over the early radioprotectors. WR-151327 provided substantial protection against neutron irradiation. Dose modification factors after single doses of cyclotron neutrons were 1.5 for both early and late skin damage and 1.5-2.4 for late muscle damage.  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