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   2693548篇
  免费   190215篇
  国内免费   5855篇
耳鼻咽喉   37711篇
儿科学   86571篇
妇产科学   76014篇
基础医学   381053篇
口腔科学   79872篇
临床医学   237673篇
内科学   521373篇
皮肤病学   61139篇
神经病学   211079篇
特种医学   103275篇
外国民族医学   659篇
外科学   410234篇
综合类   62904篇
现状与发展   10篇
一般理论   926篇
预防医学   196511篇
眼科学   65040篇
药学   199492篇
  11篇
中国医学   6429篇
肿瘤学   151642篇
  2018年   27988篇
  2017年   21597篇
  2016年   23953篇
  2015年   27179篇
  2014年   37949篇
  2013年   56515篇
  2012年   76590篇
  2011年   80996篇
  2010年   48111篇
  2009年   45450篇
  2008年   76054篇
  2007年   82009篇
  2006年   82618篇
  2005年   79460篇
  2004年   77059篇
  2003年   73817篇
  2002年   71803篇
  2001年   131534篇
  2000年   134700篇
  1999年   112686篇
  1998年   30491篇
  1997年   27226篇
  1996年   26700篇
  1995年   25499篇
  1994年   23518篇
  1993年   21899篇
  1992年   86474篇
  1991年   84046篇
  1990年   81516篇
  1989年   78874篇
  1988年   72501篇
  1987年   71278篇
  1986年   67676篇
  1985年   64314篇
  1984年   47934篇
  1983年   40852篇
  1982年   23822篇
  1981年   21512篇
  1979年   44458篇
  1978年   31277篇
  1977年   26859篇
  1976年   24637篇
  1975年   27180篇
  1974年   32562篇
  1973年   31602篇
  1972年   29815篇
  1971年   27791篇
  1970年   26092篇
  1969年   24728篇
  1968年   23241篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Ambient light affects pulse oximeters   总被引:1,自引:0,他引:1  
  相似文献   
992.
Topical analgesia for relief of post-circumcision pain   总被引:1,自引:0,他引:1  
  相似文献   
993.
994.
Three evaluation instruments (global, check-list, and criterion referenced) were used by experienced and inexperienced examiners to evaluate dental sealant end products on 40 extracted teeth. Intra- and interexaminer reliabilities were measured. Experienced examiners achieved higher intrarater reliabilities with all three evaluation instruments than did inexperienced examiners. The highest intraexaminer agreement for all examiners occurred with use of the global evaluation. The highest interexaminer reliability was achieved with the second use of the criterion-referenced evaluation by the experienced examiner. Interexaminer reliability was improved for both types of examiners with the criterion-referenced evaluation.  相似文献   
995.
996.
A 65-year-old man with spontaneous rupture of the esophagus survived with a direct suture of the esophagus 15 hours after the onset of symptoms. Endoscopic examination of the esophagus was especially of great help in determining the surgical procedure in this patient, and we want to stress the importance of prompt diagnosis and immediate surgery for this disease.  相似文献   
997.
998.
Previously, we reported that short term administration of a highly potent GnRH agonist (GnRHa) for 1 month to patients with polycystic ovarian disease (PCO) resulted in complete suppression of ovarian steroidogenesis without measurable effects on adrenal steroid production. This new study was designed to evaluate the effects of long term GnRHa administration in PCO patients with respect to their hormone secretion patterns and clinical responses. Eight PCO patients and 10 ovulatory women with endometriosis were treated daily with sc injections of [D-His6-(imBzl]),Pro9-NEt]GnRH (GnRHa; 100 micrograms) for 6 months. Their results were compared to hormone values in 8 women who had undergone bilateral oophorectomies. In response to GnRHa, PCO and ovulatory women had rises of serum LH at 1 month, after which it gradually declined to baseline. In both groups FSH secretion was suppressed throughout treatment. Serum estradiol, estrone, progesterone, 17-hydroxyprogesterone, androstenedione, and testosterone levels markedly decreased to values found in oophorectomized women by 1 month and remained low thereafter. In contrast, serum pregnenolone and 17-hydroxypregnenolone were partially suppressed, and dehydroepiandrosterone, dehydroepiandrosterone sulfate, and cortisol levels did not change. Clinically, hyperplastic endometrial histology in three PCO patients reverted to an inactive pattern, and proliferative endometrium in two other PCO patients became inactive in one and did not change in the other. Regression of proliferative endometrial histology occurred in all ovulatory women. Vaginal bleeding occurred in all women studied during the first month of GnRHa administration, after which all but one PCO patient became amenorrheic. Hot flashes were noted by all ovulatory women and by four of eight PCO patients. All PCO patients noted subjective reduction of skin oiliness, and five had decreased hair growth. We conclude that in premenopausal women: 1) chronic GnRHa administration results in apparently complete persistent suppression of ovarian steroid secretion; 2) adrenal steroid secretion is not influenced directly or indirectly; and 3) its use may be helpful in the treatment of endometrial hyperplasia and ovarian androgen excess in women with PCO.  相似文献   
999.
1000.
Positron emission tomography (PET) with fluorodeoxyglucose (FDG), magnetic resonance imaging (MRI), and CT were carried out in a patient with Alzheimer's disease 16 months before he died. At autopsy, the gross appearance of the brain correlated with MRI and CT, which showed some regional atrophy. These were much less revealing than PET, which correlated with microscopic findings of neuronal loss and proliferation of glia. In areas of moderately impaired local cerebral metabolic rate of glucose, as revealed by reduced FDG uptake, there was some gliosis, primarily around the numerous senile plaques. In areas of severe metabolic impairment, there was a profound loss of neurons, extensive gliosis, and a diminished appearance of plaques. PET-FDG is a better measure of the severity of Alzheimer's disease than MRI or CT, because it reflects the degree of neuronal pathology.  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