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   561391篇
  免费   41867篇
  国内免费   14922篇
耳鼻咽喉   5762篇
儿科学   14105篇
妇产科学   8677篇
基础医学   55526篇
口腔科学   11496篇
临床医学   63047篇
内科学   76240篇
皮肤病学   6471篇
神经病学   31064篇
特种医学   13670篇
外国民族医学   83篇
外科学   55762篇
综合类   88376篇
现状与发展   36篇
一般理论   53篇
预防医学   49663篇
眼科学   10165篇
药学   51970篇
  501篇
中国医学   41352篇
肿瘤学   34161篇
  2024年   1747篇
  2023年   8552篇
  2022年   16273篇
  2021年   22486篇
  2020年   20721篇
  2019年   25223篇
  2018年   22723篇
  2017年   20395篇
  2016年   18310篇
  2015年   17630篇
  2014年   32277篇
  2013年   34622篇
  2012年   29277篇
  2011年   32030篇
  2010年   26469篇
  2009年   24846篇
  2008年   24478篇
  2007年   26249篇
  2006年   23413篇
  2005年   21277篇
  2004年   17852篇
  2003年   15705篇
  2002年   12194篇
  2001年   11494篇
  2000年   9422篇
  1999年   8358篇
  1998年   6526篇
  1997年   6064篇
  1996年   5607篇
  1995年   5414篇
  1994年   5003篇
  1993年   4123篇
  1992年   3958篇
  1991年   3435篇
  1990年   2936篇
  1989年   2682篇
  1988年   2563篇
  1987年   2123篇
  1986年   1806篇
  1985年   4551篇
  1984年   5498篇
  1983年   3768篇
  1982年   4350篇
  1981年   3995篇
  1980年   3515篇
  1979年   3243篇
  1978年   2808篇
  1977年   2120篇
  1976年   2402篇
  1975年   1796篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
This study examined the feasibility of isolating and transferringthe centrosome-containing region of spermatozoa to mature humanoocytes. The findings demonstrate that individual sperm centrosomescan be transferred and are capable of nucleating maternal tubulinto form a well-developed sperm aster in the recipient oocyte.The results are discussed with respect to centrosome functionin early human development and applications in clinical in-vitrofertilization in the treatment of certain forms of male factorinfertility.  相似文献   
82.
超市连锁店熟食卤味销售的HACCP研究   总被引:2,自引:0,他引:2  
应用HACCP的原理和方法,对超市连锁店熟食卤味销售进行了危害因素分析,找出了关键控制点(CCP),提出了控制措施,并建议超市连锁店销售非包装熟食卤味时使用密封低温冷藏展示柜。  相似文献   
83.
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic.  相似文献   
84.
The present study evaluates the response comparability between 361 elderly hip fracture patients admitted from the community to seven Baltimore area hospitals between 1984 and 1986 and interviewer selected proxies on items pertaining to patients' pre-fracture health and functional status. Agreement across items ranges from very poor to good and varies with respect to the health or functional area assessed. Proxies tend to overestimate patient disability relative to the patients themselves, especially with regard to capacity to perform instrumental activities of daily living. Although proxies who report the greatest contact with patients respond most comparably to the patients, when they do disagree, proxies with the greatest patient contact tend to overestimate patient disability. The authors suggest that attention to item construction and phrasing may improve response comparability.  相似文献   
85.
棕榈油对成人血脂和血小板功能的影响   总被引:3,自引:0,他引:3  
张坚  王春荣 《营养学报》1997,19(2):186-190
报道了棕榈油(PA),花生油(PE)对血清总胆固醇水平(TC)在5.5~7.0mmol/L的受试者血脂和血小板功能的影响。51名受试者(男31人,女20人,年龄30~66岁之间)分为两组,一组男15人,女11人,称PE组;另一组男16人女9人,称PA组,预备期3周,膳食以当地日常食用的花生油烹调,实验期6周。PA组受试者食用以棕榈油烹调的实验膳;PE组受试者仍食花生油烹调的膳食。脂肪约占膳食能量的30%,其中60%~65%来自实验油。实验结果表明:与起始值相比,6周末PA组受试者血清TC,低密度脂蛋白胆固醇(LDL-C)和总胆固醇与高密度脂蛋白胆固醇比值(TC/HDL-C)显著下降,血浆血栓素B2(TXB2)/6-酮前列环素F1α、(6-keto-PGF1α)比值显著下降,全血血小板聚集率未见显著变化。PE组受试者的血脂、血浆TXB2、6-keto-PGF1α及全血血小板聚集率等指标均未出现显著变化。提示,棕榈油作为我国居民家庭烹调用油并不会增加发生心血管疾病的危险。  相似文献   
86.
Measurement of health-related quality of life was integrated into a randomized trial (NMSG 4/90) comparing melphalan/prednisone to melphalan/prednisone + interferon α-2b in newly diagnosed multiple myeloma. One of the aims of the study was to assess the prognostic significance of quality-of-life scores, using the EORTC QLQ-C30 questionnaire. Univariate analysis showed a highly significant association with survival from the start of therapy for physical functioning as well as role and cognitive functioning, global quality of life, fatigue and pain. In multivariate analysis, physical functioning and W.H.O. performance status were independent prognostic factors ( P values=0.001 for both) when analysed in a Cox regression model with the somatic variables β-2 microglobulin, skeletal disease and age. The best prediction for survival from the start of therapy was obtained by combining the β-2 microglobulin and physical functioning scores in a variable consisting of three risk factor levels with an estimated median survival of 17, 29 and 49 months, respectively. At a 12 months landmark analysis, the relative risk for patients with physical functioning score 0–20 v 80–100 was 5.63 (99% CI 2.76–11.49), whereas the relative risk for patients without an objective response to chemotherapy compared to those with at least a minor response was 2.32 (99% CI 1.44–3.74). Quality-of-life assessment may be an independent and valuable addition to the known prognostic factors in multiple myeloma.  相似文献   
87.
Newer policies of community care for those with disabilities have resulted in the home becoming the usual site of care. Policy makers must now give attention to the needs of those at home giving this care. This article explores the constraints on sociability opportunities of 73 mothers who were caring for children with disabilities. These opportunities are often built into leisure pursuits for women without caring responsibilities. However, choice of out-of-house leisure activity was circumscribed for the mothers in this study and their reported leisure activities revolved around home and neighbourhood. Even these sites offered limited scope for sociability because of the way in which caring affected domestic space and because of the characteristics of the modern Australian suburb. It is argued in this paper that personal time and personal domestic space are needed by care-givers so their sociability needs can be fulfilled. An understanding of the constraints imposed by use of the home as a place of care may make possible the planning of a rearrangement of domestic space to increase sociability opportunities for carers.  相似文献   
88.
李惠兰  缪鸿石 《中国康复》1993,8(3):122-124
观察了10项因素对偏瘫病人下肢功能康复的影响,其结果表明:①下肢功能水平;②平衡功能障碍;③足下垂内翻;④髋关节屈曲外旋挛缩;⑤深感觉障碍;⑥疼痛等几项因素对偏瘫病人下肢功能康复有显著的影响。  相似文献   
89.
PURPOSE: This study was undertaken to clarify the importance of bleeding vascular ectasia of the colon as the etiology of massive lower gastrointestinal hemorrhage in patients 40 years of age or younger. METHODS: An otherwise healthy 21-year-old male was admitted to a tertiary medical center with massive lower gastrointestinal hemorrhage. Technetium-labeled red blood cell scan, selective visceral angiography, and colonoscopy identified the source of bleeding as vascular abnormality of the descending colon. Segmental colonic resection was performed. RESULTS: Histologic review of the specimen demonstrated a vascular ectasia. The patient recovered uneventfully and has had no further stigmata of hemorrhage. A review of the literature was undertaken to make clear the significance of vascular ectasia as the source for massive colonic hemorrhage in the young adult. CONCLUSION: This is the first report that documents histologically a vascular ectasia as the source of massive lower gastrointestinal hemorrhage in an otherwise healthy patient less than 40 years of age. Vascular ectasia is an uncommon cause of lower gastrointestinal hemorrhage in the young adult.The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program sponsored this report #84-16-1968-532, as required by HSETCINST 6000.41A. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government.  相似文献   
90.
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