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   3451959篇
  免费   287736篇
  国内免费   13626篇
耳鼻咽喉   48338篇
儿科学   111845篇
妇产科学   89276篇
基础医学   546797篇
口腔科学   90865篇
临床医学   307506篇
内科学   616810篇
皮肤病学   91132篇
神经病学   293871篇
特种医学   137289篇
外国民族医学   686篇
外科学   536214篇
综合类   102694篇
现状与发展   23篇
一般理论   2270篇
预防医学   289081篇
眼科学   78818篇
药学   237731篇
  23篇
中国医学   9655篇
肿瘤学   162397篇
  2021年   54977篇
  2020年   35031篇
  2019年   58070篇
  2018年   71166篇
  2017年   54206篇
  2016年   59803篇
  2015年   73963篇
  2014年   108114篇
  2013年   173279篇
  2012年   91802篇
  2011年   91691篇
  2010年   116562篇
  2009年   121147篇
  2008年   79666篇
  2007年   83060篇
  2006年   93732篇
  2005年   89285篇
  2004年   91427篇
  2003年   82565篇
  2002年   72775篇
  2001年   110025篇
  2000年   104085篇
  1999年   102877篇
  1998年   66073篇
  1997年   63490篇
  1996年   61437篇
  1995年   56890篇
  1994年   51143篇
  1993年   47678篇
  1992年   72820篇
  1991年   69877篇
  1990年   66378篇
  1989年   64844篇
  1988年   60006篇
  1987年   58804篇
  1986年   55199篇
  1985年   55207篇
  1984年   49831篇
  1983年   45397篇
  1982年   41899篇
  1981年   39669篇
  1980年   37189篇
  1979年   40812篇
  1978年   35728篇
  1977年   32697篇
  1976年   30039篇
  1975年   28948篇
  1974年   29662篇
  1973年   28570篇
  1972年   26525篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Summary Split or full thickness eyelid defects resulting from tumor destruction or surgical excision present a dilemma for plastic and reconstructive surgeons. Full thickness eyelid replacement requires composite grafting of the skin, together with tarsal support of its substitute and mucosa. The flap described by Fricke in 1829 was used for reconstruction of anterior lamella in six lower eyelid defects. In three of our cases chondromucosal grafts taken from nasal septum were utilized for posterior lamella repair. The results have been satisfactory from a functional and cosmetic standpoint.  相似文献   
992.
993.
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   
994.
ABSTRACT. A 54-year-old profoundly mentally retarded female patient with phenylketonuria and a severe behaviour problem was treated with a restricted protein and high energy diet. After several weeks of dietary intervention the patient's behaviour improved significantly.  相似文献   
995.
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   
996.
Endogenous opioids are present in neurons of the vagus and the intrinsic nervous system and they are colocalized with gastrin in antral G-cells. This raises the possibility that endogenous opioids modulate gastrin release. Stimulation of both cervical vagi (10V, 5Hz, 5ms) elicited an increase of arterial plasma gastrin levels at intragastric pH7 or pH2. The response at pH2 was 30% of that at luminal pH7. Atropine reduced vagally stimulated gastrin levels substantially. At luminal pH2 the small residual noncholinergic response was mediated neither by adrenergic mechanisms nor by endogenous opioids. At luminal pH 7 adrenergic blockade with phentolamine and propranolol reduced vagally stimulated gastrin by 60%. In the presence of atropine adrenergic blockade elicited only a small inhibitory effect suggesting that vagal activation of adrenergic mechanisms depends on atropine-sensitive cholinergic pathways. Blockade of opiate receptors by naloxone had no effect on vagal gastrin release, however, the noncholinergic gastrin response was reduced significantly by naloxone, suggesting that cholinergic mechanisms normally restrain activation of endogenous opioids during vagal stimulation. Naloxone had no effect on the noncholinergic, nonadrenergic stimulation of gastrin levels. These data suggest that endogenous opioids can contribute to vagal gastrin release provided the cholinergic restraint is blocked and adrenergic mechanisms stimulate endogenous opioids. In conclusion a major role of endogenous opioids in the regulation of vagal gastrin release can not be detected.  相似文献   
997.
A retrospective study of 232 bladder tumours with minimum follow-up 5 years is presented. The carcinoma was superficial in 66%, muscle-invasive in 31% and could not be staged in 3%. Primary treatment was mainly transurethral resection for superficial tumour, but was cystectomy or radiotherapy in 22 of 29 T1 G3. Of the superficial tumours, 71% recurred. Progression to higher T stage occurred in 15% of Ta and 29% of T1 tumours, and half of these patients died of bladder cancer. The corrected 5-year survival rates in grades 1, 2A, 2B and 3-4 were 96, 84, 64 and 43%, and in stages Ta, T1, T2 and T3 they were 94, 69, 40 and 31%. All patients with T4 tumour died within 4 years. Among the 45 patients with 40 Gy irradiation + cystectomy, the corrected 5-year survival rate was 83% in superficial and 64% in muscle-invasive tumours, and among the 38 with radical radiotherapy the rates in T1-3 were 46, 36 and 13%. Transurethral resection was successful in most Ta cases. Most T1 tumours were, like T2-4, of higher grade than Ta. Prognosis was worse in T1 than in Ta. After progression to muscle-invasive disease, even during close follow-up the outlook was poor, as poor as for patients with primary muscle-invasive disease.  相似文献   
998.
A new classification of forms of progressive systemic scleroderma (PSS) is presented. Compared with previous classifications, it includes not only frequent, typical forms of PSS, but also rarer manifestations. For the first time, it considers pathogenetic factors, such as the phenomena which have become known concerning the immunological system, and distinguishes between noninflammatory and inflammatory subtypes. Etiological (in this case, immunogenetic) criteria are also considered. This classification is open to further differentiation and development.  相似文献   
999.
1000.
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