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   862089篇
  免费   70578篇
  国内免费   1839篇
耳鼻咽喉   12799篇
儿科学   24624篇
妇产科学   25111篇
基础医学   124216篇
口腔科学   25485篇
临床医学   75304篇
内科学   164555篇
皮肤病学   16979篇
神经病学   70082篇
特种医学   35191篇
外国民族医学   171篇
外科学   136152篇
综合类   24604篇
现状与发展   2篇
一般理论   263篇
预防医学   66872篇
眼科学   20519篇
药学   64718篇
中国医学   1594篇
肿瘤学   45265篇
  2018年   7331篇
  2015年   7729篇
  2014年   11108篇
  2013年   16777篇
  2012年   22710篇
  2011年   23835篇
  2010年   13863篇
  2009年   13061篇
  2008年   22565篇
  2007年   24616篇
  2006年   24488篇
  2005年   24135篇
  2004年   23695篇
  2003年   22831篇
  2002年   21927篇
  2001年   35824篇
  2000年   36466篇
  1999年   30896篇
  1998年   9225篇
  1997年   8545篇
  1996年   8477篇
  1995年   8006篇
  1994年   7725篇
  1992年   26662篇
  1991年   26099篇
  1990年   25620篇
  1989年   24682篇
  1988年   23222篇
  1987年   22887篇
  1986年   21743篇
  1985年   21103篇
  1984年   16386篇
  1983年   13997篇
  1982年   8854篇
  1981年   8202篇
  1980年   7671篇
  1979年   16740篇
  1978年   12115篇
  1977年   10186篇
  1976年   9328篇
  1975年   10149篇
  1974年   12641篇
  1973年   12136篇
  1972年   11540篇
  1971年   10686篇
  1970年   10219篇
  1969年   9909篇
  1968年   8900篇
  1967年   8230篇
  1966年   7657篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
In 1981 a statewide program supplying free insulin to 3,720 patients of state health clinics was discontinued. We attempted to assess whether this action had an adverse effect medically and financially on those concerned. A computer randomized sample of 351 patients (9%) was studied by personal interview and questionnaire. Information obtained focused on certain events that occurred 18 months before and after the program ceased. Measurements used to determine medical impact were number of hospitalizations, emergency room and physician visits, changes in weight and glucose levels, and episodes of ketoacidosis. Financial impact was measured by cost of hospitalization and physician visits. Our results revealed no significant changes in any of the medical parameters studied except for fasting serum glucose levels above 300 mg/dl, which occurred less frequently after the free insulin program was discontinued. There were fewer hospitalizations, more visits to physicians, and no change in number of emergency room visits after discontinuance of the free program. The overall cost saving was estimated to be +883,558 for the 18-month study period, in addition to the +550,000 the plan had been costing the state.  相似文献   
82.
83.
The administration of prophylactic antibiotics in surgery is appropriate for many patients. Data have shown extending the duration of prophylaxis beyond 48 hours does not lower the rate of postoperative-infection. The purpose of this project was to concurrently assess the duration of prophylactic antibiotic use. A total of 95 patients were monitored over 3 weeks. Eighty patients (84.2%) received antimicrobial therapy. In 23 of these patients (28.75%) the duration of antibiotic administration was longer than 2 days without clinical or microbiological evidence of infection. In 5 other patients only postoperative antibiotics were prescribed. The cost difference between the actual duration of antibiotic administration and 2 days of the same regimen was +1,364.58. Extrapolating for one year, it can be estimated that antibiotic costs could be reduced about +23,600. Pharmacists can focus on the duration of antibiotic prophylaxis as a cost containment measure.  相似文献   
84.
The percentage uptake of [123I]metaiodobenzylguanidine (MIBG) by tumors of the paraganglion system is compared with the number of neurosecretory granules (assessed by both light and electron microscopy) in the subsequently resected tumors in six patients. Iodine-123 MIBG was injected intravenously; the tumor uptake of [123I]MIBG varied between 0.001% and 0.14% of the injected dose per gram of tumor tissue at 22 hr. The number of neurosecretory granules in tissue sections was scored on a scale of I-III. A direct proportional correlation was found between the percentage uptake of [123I]MIBG by the tumor and the number of neurosecretory granules in the tissue sections but not with plasma or urinary catecholamines. This technique for imaging reflects the storage status of the tumor better than plasma and urinary catecholamine measurements.  相似文献   
85.
86.
Abstract A high frequency of serum complement component C4A deficiency may explain the higher prevalence and greater severity of systemic lupus erythematosus reported in Australian Aborigines. Inherited deficiencies of serum complement components C4A, C4B, and C2 were examined in two Australian Aboriginal populations from Darwin and Alice Springs and compared with the prevalence of complement deficiencies in white Australian blood donors. The frequency of C4A deficiency alleles was 29% in Darwin Aborigines compared with 12% in Alice Springs and 17% in Canberra blood donors. Partial C4B deficiency was also higher in Darwin Aborigines than in the other populations. Inherited deficiency of serum complement component C2 was not observed.  相似文献   
87.
88.
89.
Using cortical cups in chloralose-urethanized rats, the in vivo release of cholecystokinin-like immunoreactivity (CCK-LI) from cerebral cortex was examined. Resting levels of cholecystokinin-like immunoreactivity ranged from 20 to 30 pg/20 min sample. The addition of potassium (40 mM) in excess, resulted in a highly significant elevation in the levels of CCK-LI in the cortical superfusate. Deletion of calcium and the substitution of cobalt (10 mM), resulted in a significant reduction in both resting release and the release otherwise evoked by the addition of potassium. Focal electrical stimulation of the cortex (20 Hz), resulted in a significant (1.9 +/- 0.2-fold, n = 8) increase in the levels of CCK-LI. The addition of glutamate (10(-6)-10(-4) M) of kainic acid (10(-8)-10(-6) M), also resulted in significant elevations in the levels of CCK-LI. The co-administration of a putative glutamate receptor antagonist, kynurenic acid (10(-4) M) resulted in a significant reduction in the levels of release otherwise evoked by the addition of glutamate, but not by electrical stimulation. The addition of GABA (10(-5)-10(-3) M) resulted in a dose-dependent decrease in the resting release of CCK-LI, and the release evoked by glutamate. Picrotoxin (10(-6)-10(-4) M), resulted in a highly significant increase in the levels of CCK-LI in the cortical effluent. These results are consistent with a tonic GABAergic inhibition of CCK-releasing neurons. The treatment of the animal with diazepam (30 mg/kg, i.p.) also resulted in a significant reduction in resting release and the release otherwise evoked by focal cortical stimulation.  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