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   862955篇
  免费   70622篇
  国内免费   1840篇
耳鼻咽喉   12805篇
儿科学   24655篇
妇产科学   25174篇
基础医学   124327篇
口腔科学   25484篇
临床医学   75414篇
内科学   164672篇
皮肤病学   16991篇
神经病学   70187篇
特种医学   35225篇
外国民族医学   171篇
外科学   136275篇
综合类   24610篇
现状与发展   2篇
一般理论   265篇
预防医学   66883篇
眼科学   20580篇
药学   64820篇
中国医学   1594篇
肿瘤学   45283篇
  2018年   7340篇
  2015年   7744篇
  2014年   11134篇
  2013年   16814篇
  2012年   22746篇
  2011年   23882篇
  2010年   13885篇
  2009年   13092篇
  2008年   22612篇
  2007年   24650篇
  2006年   24539篇
  2005年   24177篇
  2004年   23750篇
  2003年   22868篇
  2002年   21967篇
  2001年   35854篇
  2000年   36496篇
  1999年   30909篇
  1998年   9234篇
  1997年   8551篇
  1996年   8482篇
  1995年   8015篇
  1994年   7734篇
  1992年   26670篇
  1991年   26109篇
  1990年   25631篇
  1989年   24690篇
  1988年   23225篇
  1987年   22895篇
  1986年   21748篇
  1985年   21111篇
  1984年   16400篇
  1983年   14008篇
  1982年   8862篇
  1981年   8208篇
  1980年   7677篇
  1979年   16754篇
  1978年   12116篇
  1977年   10184篇
  1976年   9330篇
  1975年   10152篇
  1974年   12645篇
  1973年   12148篇
  1972年   11543篇
  1971年   10689篇
  1970年   10220篇
  1969年   9909篇
  1968年   8904篇
  1967年   8236篇
  1966年   7655篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
In 1985, we initiated a prospective clinical trial to evaluate the risk of recurrence for superficial bladder cancer. Up to now, 41 patients subjected to TUR have subsequently been monitored by immunocytology with a monoclonal antibody (mab 486 p) recently developed in our laboratory. Of these patients, 15 (36.6%) remained marker-negative and received no prophylactic therapy. There was only one recurrence (6.7%) in this subset of patients, whereas 10 out of 26 (38.5%) marker-positive patients have so far developed recurrent malignancies. In all cases, the conversion of immunocytological characteristics preceded visible recurrence by 2-5 months. These preliminary results indicate that immunocytology might make it possible to identify patients at low risk of recurrence more accurately than has so far been feasible with standard cytology or flow-cytometry.  相似文献   
102.
103.
Biological oxidation of 2,4-diamino-6-substituted pyrimidines have been studied using hepatic microsomes from various mammalian species. The nature of the enzyme(s) involved in the oxidation has been elucidated using various enzyme inhibitors and inducing agents. The 3-N-oxides were formed with 6-piperidino-, 6-diethylamino-, 6-methyl-, and 6-chloro-substituted 2,4-diaminopyrimidines: no evidence of 1-N-oxide formation was obtained. With the 6-hydroxy-, 6-amino-, and unsubstituted 2,4-diaminopyrimidines and melamine, no N-oxidative metabolite was detected. The differences in N-oxide formation was discussed in terms of the effect of substituents on tautomerism and electron distribution. The N-oxygenation was mediated via a cytochrome P450 dependent system.  相似文献   
104.
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   
105.
106.
Neutropenic enterocolitis in adults with acute leukemia   总被引:2,自引:0,他引:2  
Neutropenic enterocolitis has been previously described only by case reports and literature reviews. Of 499 adults with acute leukemia seen over a 23-year period (1962 to 1985), 13 cases (2.6%) of neutropenic enterocolitis have been reported. Eleven of these 13 patients were profoundly neutropenic (mean white blood cell count, 472/cu mm) and developed abdominal symptoms during either initial induction or relapse of acute leukemia. Histologic confirmation was available in ten cases, five cases after surgical resection and five cases at autopsy after nonoperative management. Three patients with isolated ileocecal inflammation without infarction at the time of surgery were successfully managed without resection. Five patients treated with surgery died four to 64 weeks postoperatively (mean survival, 21.6 weeks) of nonsurgical complications of leukemia. Three patients were still alive, one patient 42 months after right hemicolectomy and two patients five months after exploration only. All five patients managed medically died an average of 1.4 days (range, zero to four days) after the onset of abdominal pain. Survival in patients with acute leukemia who develop neutropenic enterocolitis is determined by early recognition and appropriate surgical exploration that can be expected to yield an acceptable operative mortality.  相似文献   
107.
Clinical experience of phototherapy for non-haemolytic hyperbilirubinaemia in 3999 infants in Kandang Kerbau Hospital, Singapore, is documented. Phototherapy was most effective in extremely preterm infants with very low birth weight (gestation less than or equal to 32 weeks, birth weight less than or equal to 1500 g) and least effective in full term infants with very low birth weight (gestation greater than or equal to 37 weeks, birth weight less than or equal to 1500 g) and large preterm infants (gestation less than 37 weeks, birth weight greater than 2270 g). Overall, phototherapy was effective in almost all the infants, with a failure rate of only 2.00/1000 infants. No characteristic features common to all the failures could be detected. The bilirubin rebound was usually mild; repeat phototherapy was required in only 30 infants (7.50/1000), with the response to the second exposure comparable to that to the first. No infant required a third exposure. All the infants tolerated phototherapy well, none developing any illness that could be attributed to the treatment. This clinical experience shows that phototherapy for the treatment of nonhaemolytic hyperbilirubinaemia is effective and safe.  相似文献   
108.
109.
Metoclopramide, a substituted benzamide derivative, was orally administered to a patient with intractable hiccups. Dysphoria, akathisia, depressed mood with suicidal ideation, insomnia, racing thoughts, and labile affect were seen following the administration of metoclopramide. The episode met criteria for an organic affective syndrome. It is suggested that the mental status of patients undergoing metoclopramide therapy be monitored, since these symptoms have not been previously reported.  相似文献   
110.
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