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   282217篇
  免费   23446篇
  国内免费   6674篇
耳鼻咽喉   3578篇
儿科学   6014篇
妇产科学   4276篇
基础医学   22783篇
口腔科学   8135篇
临床医学   26337篇
内科学   28855篇
皮肤病学   2942篇
神经病学   13151篇
特种医学   7543篇
外国民族医学   16篇
外科学   35828篇
综合类   45706篇
现状与发展   12篇
一般理论   29篇
预防医学   33513篇
眼科学   2828篇
药学   26305篇
  452篇
中国医学   32967篇
肿瘤学   11067篇
  2024年   1198篇
  2023年   5651篇
  2022年   10270篇
  2021年   13943篇
  2020年   13030篇
  2019年   14639篇
  2018年   12864篇
  2017年   11232篇
  2016年   10242篇
  2015年   9594篇
  2014年   18885篇
  2013年   19049篇
  2012年   16411篇
  2011年   18188篇
  2010年   15143篇
  2009年   12748篇
  2008年   11878篇
  2007年   12032篇
  2006年   10552篇
  2005年   8944篇
  2004年   7386篇
  2003年   6473篇
  2002年   5039篇
  2001年   4299篇
  2000年   3653篇
  1999年   3048篇
  1998年   2488篇
  1997年   2253篇
  1996年   1871篇
  1995年   1850篇
  1994年   1678篇
  1993年   1427篇
  1992年   1329篇
  1991年   1220篇
  1990年   1049篇
  1989年   1030篇
  1988年   953篇
  1987年   859篇
  1986年   783篇
  1985年   2210篇
  1984年   2501篇
  1983年   1600篇
  1982年   2086篇
  1981年   1536篇
  1980年   1349篇
  1979年   1223篇
  1978年   1009篇
  1977年   790篇
  1976年   875篇
  1975年   586篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The increasing demands of clinical audit have resulted in the need for accurate data collection. The use of tumour maps allows standardization of the records of patients with head and neck cancer, which facilitates collation of data in multicentre studies and makes interdepartmental comparisons more meaningful. The aim of this study was to develop an improved standard set of tumour maps for recording the stage of head and neck tumours. A review of the existing tumour diagrams was performed to identify those anatomical areas that are not adequately represented or where ambiguity exists. The areas where improvements could be made were identified as: (1) the anterior commissure of the larynx; (2) axial and sagittal views of the larynx; (3) the pyriform fossa and cervical oesophagus; (4) the oropharynx and vallecula; (5) the nasal cavity and paranasal sinuses; and (6) cervical nodal involvement. A new set of tumour maps is presented in an attempt to correct some of the limitations of the existing diagrams.  相似文献   
72.
Summary Quantitative aspects of the microanatomy of the pineal gland and other neuroendocrine and circumventricular structures were studied in a small, reproductively suppressed, female Naked Mole-rat from central Kenya, Africa. The atrophic pineal is the smallest in absolute size (0.002135 mm3) of any so far described in a species of rodent, and in size relative to body weight is second only to that of another tropical species. The subcommissural organ and posterior collicular recess are also relatively small and less well differentiated than those in most other examined rodent species. In contrast, the subfornical organ, OVLT and median eminence are large and well vascularized. It is concluded that the pineal in this species follows the previously described trend among rodents of relatively smaller size in species whose centers of distribution are in lower latitudes. Although the pineal is atrophic, the Naked Mole-rat still exhibits 24-hour and seasonally timed patterns of behavior and seasonal reproduction. However, in this species these events are probably cued by moisture, temperature and social factors rather than by photic information.  相似文献   
73.
Abstract. A total of 81 rat kidney grafts, flushed out and cold stored in either Sacks' or University of Wisconsin (UW) solution, were transplanted into hemodiluted (Hct = 30%± 4%) or untreated (Hct = 43%± 3%) recipients. The cold ischemia times (CIT) used were 24 and 36 h. One week after transplantation, the surviving recipients ( n = 67) were contralaterally nephrectomized. The experiment was terminated after a total period of 4 weeks, and the percentage of surviving animals was determined for each treatment. Data was pooled and the results show that grafts cold stored in UW solution were viable to a significantly greater extent and after longer CIT than grafts cold stored in Sacks' solution (47% vs 23%; P < 0. 05). Recipient hemodilution did not improve graft viability (39% vs 32%; NS). Kidneys cold stored for 24 h were viable to a greater extent than kidneys with a CIT of 36 h (50% vs 15%; P < 0. 01).  相似文献   
74.
Biliary obstruction and multiple hepatic abscesses occurred in a patient after ligation of a segmental branch of the right hepatic duct. The patient was successfully managed by transhepatic biliary drainage and balloon dilatation of an internal fistula that developed between the ligated duct and a Roux limb of jejunum. Internal biliary fistulas may be dilated using interventioanl radiologic techniques to permit nonobstructed bile flow. Implications for the nonsurgical treatment' of biliary strictures are discussed.  相似文献   
75.
While an exacerbation in allergic symptoms corresponding to seasons has long been reported, few studies have investigated the association between the season of birth and allergic disorders. The aim of this study was to investigate whether the climatologic data before and after birth affected the incidence of atopic dermatitis (AD) and the results of allergy-related blood tests in early infancy. From February 1995 to January 2000, 2136 infants were tested for AD and followed for 12 months. AD patients were tested by using allergy-related blood tests. Data were compared according to the month of birth and the climatologic data using a computed statistical software package. Six hundred and thirty infants had AD before 12 months old, and significant differences were found according to the season of birth (p < 0.0001). Infants born in spring showed the lowest (22.3%) incidence, while those born in autumn showed the highest (34.6%). In 369 patients, total serum IgE levels, and serum specific IgE levels with egg white at 3 months old were also different according to the season of birth. All of these levels were lower in patients born in spring and summer, and higher in patients born in autumn and winter. Furthermore, the cumulative sunshine amount during the 3 months before and after birth was inversely correlated, while the average temperature over the 3 months before birth was positively correlated to the incidence of AD according to the month of birth. The climatologic data around birth may play an important role in whether an infant develops allergies.  相似文献   
76.
Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (−Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from −Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, −Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits.  相似文献   
77.
78.
79.
PURPOSE: To describe and discuss the status of patient safety in U.S. hospitals. METHODS: Personal interview. This report is part of a series of discussions with a leading expert on patient safety. FINDINGS AND CONCLUSIONS: Some improvements have been made in the past 10 years. But changes have not been adequate. Continuing barriers include the punitive environment in hospitals, physicians' denial of the scope of the problem, lack of national leadership, and lack of systems thinking.  相似文献   
80.
介绍我国援外医疗队在 3 6个国家以 17种治疗方法为主治疗 40多种病的概况。  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