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   33235篇
  免费   2399篇
  国内免费   87篇
耳鼻咽喉   335篇
儿科学   882篇
妇产科学   683篇
基础医学   4914篇
口腔科学   548篇
临床医学   3102篇
内科学   7511篇
皮肤病学   760篇
神经病学   2709篇
特种医学   911篇
外国民族医学   3篇
外科学   4723篇
综合类   421篇
一般理论   29篇
预防医学   3302篇
眼科学   585篇
药学   2101篇
  1篇
中国医学   64篇
肿瘤学   2137篇
  2021年   400篇
  2020年   261篇
  2019年   436篇
  2018年   536篇
  2017年   358篇
  2016年   428篇
  2015年   502篇
  2014年   775篇
  2013年   1119篇
  2012年   1657篇
  2011年   1838篇
  2010年   1087篇
  2009年   1105篇
  2008年   1742篇
  2007年   1934篇
  2006年   1892篇
  2005年   1982篇
  2004年   1827篇
  2003年   1720篇
  2002年   1730篇
  2001年   642篇
  2000年   589篇
  1999年   566篇
  1998年   488篇
  1997年   457篇
  1996年   419篇
  1995年   449篇
  1994年   329篇
  1993年   313篇
  1992年   508篇
  1991年   502篇
  1990年   442篇
  1989年   366篇
  1988年   350篇
  1987年   351篇
  1986年   355篇
  1985年   351篇
  1984年   338篇
  1983年   302篇
  1982年   316篇
  1981年   307篇
  1980年   264篇
  1979年   269篇
  1978年   224篇
  1977年   223篇
  1976年   175篇
  1974年   188篇
  1973年   180篇
  1972年   174篇
  1971年   180篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
A computer-assisted method for the registration of food intakes in real time according to a concise and simple procedure was subjected to a series of controls in order to assess precision. The method employs the 'portion' of a composite dish as unit of measure. The constancy of the portion was tested. The results show that the recipes of the diet of a subject may be stored and utilized in deferred time without loss of precision: data to be recorded in real time are then very limited. The length of period of analysis was also studied. The time of investigation should not be shorter than two weeks to obtain precise information on the feeding habits of an individual subject, whereas for a group of subjects the diary of a single day provides information of sufficient precision.  相似文献   
43.
44.
45.
Aplastic anaemia is both frequent and difficult to manage in patients with dyskeratosis congenita (DC). We recently treated a 23-year-old male for a year with granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Ep), with an excellent neutrophil response, and a transient effect on haemoglobin levels. G-CSF alone or combined with other cytokines may provide at least a partial effect in pancytopenic patients with DC.  相似文献   
46.
OBJECTIVE: This study was designed to determine if resection of positive regional nodes in patients with breast cancer provided a group of cured patients. SUMMARY BACKGROUND DATA: Previous studies of long-term follow-up of patients with breast cancer have demonstrated that 30% of patients with positive nodes may be alive at 10 or 20 years. Randomized, prospective studies have not shown a difference in survival between modified radical and total mastectomy. METHODS: The authors analyzed the statistical basis of randomized, prospective studies of breast cancer. Patients from University and Kings County Hospital with breast cancer were observed (n = 1024) and the 10-year survival curves were analyzed. Data from the Surveillance, Epidemiology, and End Results (SEER) program were evaluated to determine the prognosis of patients with positive-node breast cancer who survived 10 and 15 years. RESULTS: The authors found that no current randomized study of primary treatment of breast cancer has the power to determine the advantage of one treatment over another if the primary cancer is treated. Additionally, evaluation of the patients in this study demonstrated that those with regional disease usually had a recurrence by 7 years; however, at 10 years, 30% are still alive and have the same prognosis as patients with negative-node breast cancer. CONCLUSIONS: Regional breast cancer is a curable disease in some resected patients.  相似文献   
47.
48.
Following the well-known European CCRs of Manchester and Turin, 2 regional CCRs have been recently created in France: in Nancy (1983) and Marseille (1984); both are population based CCRs, covering respectively 535,200 and 809,200 children (0-14 yrs). All malignant neoplasms are included, as well as brain tumours (whatever grading) and borderline malignancies. Data are collected from medical and administrative sources. Registration is active and every source is recontacted annually. The registries contact all physicians who might include children among their patients (private and hospital practice), and laboratories of pathology-cytology. The University Hospital Centers and Anti-Cancer Centers in adjacent regions, and in Paris are contacted. Death certificates for children dying of a malignant neoplasm are also sent to the registry. Data collected are as follows: name, age, sex, address, date and method of diagnosis, histological type, anatomical site, stage, treatment and sources of information. We added the data of a general cancer registry, created in Strasbourg in 1975 and covering 205,900 children. reliability of the methodology is attested by the similarity of the results obtained in other European, US and Australian CCRs. In conclusion, this type of registry is needed to organize multicentric epidemiological studies about the role of etiological factors, the survival, and the long term sequelae.  相似文献   
49.
Toxicity testing of sediment samples from the Rio Santiago and its main tributaries was performed using a battery of tests that included the ECHA dipstick biocide monitor, the MetPad test, the lettuce seed germination and the root elongation test, the nematode test, spot plate test, and the SOS Chromotest. Assessment was carried out on organic extracts, pore water, and direct sediment. Results of bioassays showed toxicity sources from tributaries and canals flowing into the river and areas being degraded by insults from industrial spills. © by John Wiley & Sons, Inc.  相似文献   
50.
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