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   3211069篇
  免费   233166篇
  国内免费   7152篇
耳鼻咽喉   43869篇
儿科学   104477篇
妇产科学   86981篇
基础医学   470252篇
口腔科学   89623篇
临床医学   299667篇
内科学   614233篇
皮肤病学   68645篇
神经病学   258358篇
特种医学   118379篇
外国民族医学   810篇
外科学   470716篇
综合类   69792篇
现状与发展   13篇
一般理论   1227篇
预防医学   261896篇
眼科学   74211篇
药学   238486篇
  16篇
中国医学   6828篇
肿瘤学   172908篇
  2021年   25859篇
  2019年   26755篇
  2018年   37090篇
  2017年   27968篇
  2016年   30942篇
  2015年   35116篇
  2014年   49189篇
  2013年   75067篇
  2012年   102926篇
  2011年   109668篇
  2010年   64863篇
  2009年   60622篇
  2008年   102037篇
  2007年   108552篇
  2006年   109375篇
  2005年   105911篇
  2004年   101127篇
  2003年   96995篇
  2002年   93812篇
  2001年   142504篇
  2000年   146492篇
  1999年   123300篇
  1998年   36584篇
  1997年   32183篇
  1996年   32199篇
  1995年   30437篇
  1994年   28269篇
  1993年   26594篇
  1992年   96817篇
  1991年   94976篇
  1990年   92426篇
  1989年   88606篇
  1988年   81764篇
  1987年   80198篇
  1986年   75711篇
  1985年   72575篇
  1984年   54241篇
  1983年   46354篇
  1982年   27768篇
  1979年   50008篇
  1978年   35736篇
  1977年   29602篇
  1976年   28594篇
  1975年   30266篇
  1974年   36548篇
  1973年   35230篇
  1972年   32879篇
  1971年   30994篇
  1970年   28717篇
  1969年   26918篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Modern medicine has made many advances in the capability to sustain life. The dental profession needs to keep up to date with these changes and be creative in caring for these individuals who are medically compromised and who require special care.11 This sometimes requires the purchase of new equipment; other times it means modifying that which exists. In all instances, the level of care for these individuals requires a team approach and mandates education of all team members. In the case presented, the medical problems necessitated such a team effort to achieve optimal care.  相似文献   
993.
Renal magnesium wasting in two families with autosomal dominant inheritance   总被引:3,自引:0,他引:3  
Hypomagnesemia due to isolated renal magnesium loss was demonstrated in two unrelated families with autosomal dominant mode of inheritance. Magnesium infusions performed in two patients showed not only a reduced renal magnesium threshold but also a lowered renal tubular maximum for magnesium. All members of both families who presented with hypomagnesemia had also a lowered excretion of calcium in the urine, presumably as a consequence of increased reabsorption in Henle's loop.  相似文献   
994.
995.
996.
The use of adjuvant radiation therapy in breast cancer patients treated with mastectomy and adjuvant chemotherapy has been controversial. In order to assess the necessity and effectiveness of adjuvant radiation therapy in this setting, we reviewed the results in 510 patients with T1-T3 tumors and pathologically positive nodes or tumors larger than 5 cm and negative nodes who were treated with adjuvant chemotherapy. Patients with four or more positive nodes or at least one positive apical node were randomized to receive either five or ten cycles of cyclophosphamide/Adriamycin (Adria Laboratories, Columbus, OH) (CA) and patients with one to three positive nodes or operable tumors larger than 5 cm and pathologically negative nodes were randomized to receive eight cycles of either cyclophosphamide, methotrexate, and 5-fluorouracil (5-FU) (CMF) or methotrexate and 5-FU (MF) chemotherapy. Two hundred six of these patients were subsequently rerandomized to receive either no further treatment or adjuvant radiotherapy. Thirty-five patients withdrew after randomization, including 34 who declined to receive radiotherapy. Radiation therapy consisted of 4,500 cGy in 5 weeks to the chest wall and appropriate draining lymph nodes. Median follow-up from chemotherapy randomization is 45 months for patients in the CA arm and 53 months for those in the CMF/MF arm. The crude rate of local failure (chest wall or draining lymph node areas) as first site of failure for patients randomized to receive chemotherapy only was 14%; for those randomized to receive both chemotherapy and radiotherapy it was 5% (P = .03). For patients in the CMF/MF arm, the rate of local failure as the first site of failure was nearly the same for patients randomized to chemotherapy only as for those randomized to adjuvant radiotherapy as well (5% v 2%). For patients in the CA arm, the crude rate of local failure was 20% for patients randomized to receive chemotherapy only, and 6% for those randomized to both types of adjuvant treatment (P = .03). Among the 43 patients treated with CA who actually received radiotherapy, there was only one local failure, compared with 12 local failures among the 59 patients (20%) who actually did not receive radiotherapy (P = .007). No significant difference was seen in disease-free survival or overall survival in either the CA or the CMF/MF arm between patients randomized to receive radiation therapy and those randomized to no further treatment.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
997.
A patient with keratoconus suffered two traumatic ruptures of her corneal graft wound, both of which were successfully repaired with restoration of graft clarity. There were also two apparently unrelated episodes of rejection. The endothelium was monitored by specular microscopy during this period. Our findings suggest that the insult to a transplanted cornea from an episode of rejection may be greater than that from traumatic wound rupture.  相似文献   
998.
The aim of the study was to determine the effect of exogenous melatonin treatment on circulating prolactin levels in red deer. Melatonin was administered from 12 June 1984 (day 1) to lactating and non-lactating hinds in the feed daily at 1600 h, and to non-lactating hinds by a subcutaneous implant. Average concentrations (ng/ml) of prolactin in plasma taken serially over 15-h periods were significantly higher for untreated hinds than for melatonin-treated animals on day 15 whether lactating (66-133 v. 23-28, P less than 0.05) or non-lactating (28-174 v. 8-13, P less than 0.01), remained higher on day 36 (lactating: 41-152 v. 15-21, P less than 0.05; non-lactating: 21-50 v. 1-7, P less than 0.001) but had decreased to similar levels on day 72 (lactating: 5-24 v. 7-17; non-lactating: 2-9 v. 0-4). The advanced reduction in plasma prolactin for all melatonin-treated hinds was associated with an advanced onset of seasonal breeding activity.  相似文献   
999.
1. The evidence is accumulating to suggest that glycine, the simplest amino acid, is conditionally essential in man. Benzoic acid, by conjugation with glycine to form hippuric acid, is known to deplete the free glycine pool of the body. Glycine is one substrate for the enzyme glutathione synthase (EC 6.3.2.3) and in the inborn error of metabolism in which glutathione synthase function is defective, increased quantities of 5-oxoproline are excreted in the urine. 2. An oral dose of 4-10 g sodium benzoate was given to six normal adults to deplete the metabolic pool of glycine, and the urinary excretion of 5-oxoproline was followed for 6 h. In five of the six, a significant increase in the urinary 5-oxoproline was seen within 3 h. 3. These findings show that 5-oxoprolinuria can result from limited glycine availability, and may provide a useful test for assessing glycine sufficiency in a range of physiological and pathological states.  相似文献   
1000.
A method for measuring flow based on the shifting of the rephasing pulse following slice selection in partial saturation is described. The technique is based on a partial saturation sequence and retains much of the high signal which is a feature of the use of this sequence. Images obtained while encoding for the flow signal compated with those when not encoding appear very similar.  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