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   1917577篇
  免费   138801篇
  国内免费   7107篇
耳鼻咽喉   24588篇
儿科学   62720篇
妇产科学   51552篇
基础医学   278785篇
口腔科学   51346篇
临床医学   172175篇
内科学   380112篇
皮肤病学   45116篇
神经病学   146992篇
特种医学   79582篇
外国民族医学   417篇
外科学   295527篇
综合类   38687篇
现状与发展   4篇
一般理论   510篇
预防医学   151568篇
眼科学   41733篇
药学   138056篇
  8篇
中国医学   3263篇
肿瘤学   100744篇
  2018年   20988篇
  2017年   17257篇
  2016年   19365篇
  2015年   22736篇
  2014年   29194篇
  2013年   40982篇
  2012年   57224篇
  2011年   56793篇
  2010年   34151篇
  2009年   34181篇
  2008年   50629篇
  2007年   55108篇
  2006年   55858篇
  2005年   61467篇
  2004年   61056篇
  2003年   55472篇
  2002年   48876篇
  2001年   85961篇
  2000年   86234篇
  1999年   75081篇
  1998年   21234篇
  1997年   18647篇
  1996年   19665篇
  1995年   19628篇
  1994年   18186篇
  1993年   17145篇
  1992年   63168篇
  1991年   63280篇
  1990年   61622篇
  1989年   59213篇
  1988年   54778篇
  1987年   53967篇
  1986年   50734篇
  1985年   48596篇
  1984年   36530篇
  1983年   30758篇
  1982年   18010篇
  1981年   16127篇
  1979年   33769篇
  1978年   24058篇
  1977年   19976篇
  1976年   18883篇
  1975年   21068篇
  1974年   24662篇
  1973年   23460篇
  1972年   21827篇
  1971年   20420篇
  1970年   18934篇
  1969年   17724篇
  1968年   16568篇
排序方式: 共有10000条查询结果,搜索用时 794 毫秒
991.
Total gastrectomy is discussed as the operation of choice among different surgical approaches for gastric carcinoma. We prefer the performance of an elective total gastrectomy with systematic lymphadenectomy (compartments I and II) and obligatory splenectomy. A retrospective study of 1,704 consecutive cases of gastric carcinomas showed a better outcome following total gastrectomy in relationship to distal subtotal gastrectomy, but these results cannot be used as evidence because of the lack of a prospective study. Nevertheless, a precise analysis of our cases in regard to tumor site and tumor type could show a frequency of only 6% to maximally 30%, in which elective total gastrectomy may represent a procedure too extensive to justify for an oncological course.  相似文献   
992.
This paper discusses the application of intravenous Kalipsol anesthesia in combination with Seduxen (Relanium) in 22 patients who underwent antro-mastoidectomy (expanded) and fronto-ethmoidectomy. No complications related to the method of anesthesia were identified. It is concluded that the use of Kalipsol anesthesia in urgent ENT operations provides better surgical intervention. This method ensures adequate analgesia during operation.  相似文献   
993.
This paper reports the changes in prolactin levels after 12 spontaneous and 52 induced pregnancies in 54 women with unambiguous hyperprolactinaemia (median plasma prolactin levels 67.5 ng/ml, range 40-400). Twenty-three of the patients showed radiological evidence of prolactinoma. The pregnancies were induced in 37 patients by bromocriptine, in nine by metergoline, in two by lisuride and in four by other treatments. Of the 64 pregnancies, 16 ended in spontaneous abortion, while 48 went to term. Follow-up was continued for at least 6 months after delivery or until the end of lactation. In a control group of 32 hyperprolactinaemic women (median prolactin 70 ng/ml, range 40-400) not wishing to become pregnant, prolactin changes were similarly registered over a mean period of 15 months without any treatment (range 6-38 months). After pregnancy, a significant downward trend of plasma prolactin was observed in the puerperal women with a 'normalization' rate of 17%. No changes were observed in the 32 controls who did not become pregnant.  相似文献   
994.
A patient with Graves' disease had a symptomatic thrombocytopathy during periods of remission. When euthyroid, she noticed bruising, petechiae, and epistaxis. Hemostatic abnormalities included prolongation of the bleeding time by aspirin, reduced platelet retention (a second-phase defect), and abnormal thrombin-induced aggregation and serotonin release. When hyperthyroid, bleeding symptoms resolved, and platelet function returned to normal. These observations suggest that mild bleeding disorders may be influenced either directly or indirectly by thyroid hormone levels.  相似文献   
995.
Human subjects maintained isometric plantar or dorsal flexions of the ankle in a matching task. H-reflexes of different sizes were superimposed on the steady activity. The peak-to-peak amplitude of the reflexes was measured on the electromyogram (EMG) of the soleus muscle. The size of the corresponding muscle contractions was determined on the isometric torque signal in relation to the maintained flexion force. The EMG-torque relation which was defined as the reflex muscle contraction as a function of the EMG reflex signal approximated a square root function for a given steady contraction level. It was not modulated by steady dorsal flexions, but it decreased continuously with stronger plantar steady torques. This dependence was caused by the silent period following the reflex discharge. Since the reflex discharge and the silent period were near in time to the duration of the contraction, the silent period had a direct effect on the reflex contraction amplitude.  相似文献   
996.
Department of Biology, Izhevsk Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 107, No. 3, pp. 353–356, March, 1989.  相似文献   
997.
The alkylating agent ifosfamide synthesized according to own method at the Institute of Pharmaceutical Industry, Warsaw, was compared in biological evaluations with Holoxan (Asta-Werke's ifosfamide). No significant differences between tested compounds were found in respect of acute toxicity and antitumor activity in experimental systems in mice.  相似文献   
998.
Formulae for the calculation of the count of microorganisms isolated from natural bacterial biocenoses of a child's body have been derived. The authors suggest a variant of simplified drip method for the computation of microorganism colonies in solid media. The described method helps cut down the nutrient media consumption at least 3-fold and is time-saving.  相似文献   
999.
An experiment was carried out to investigate the effect of a range of estradiol (E2) doses (0.1-6.5 micrograms/g body wt/day) on vitamin D metabolism and the plasma levels of growth hormone (GH) and prolactin (PRL) in the growing chick. Doses of 0.5-0.7 microgram/g E2, which are insufficient to raise the plasma calcium level, did induce an increase in growth rate, an increase in 25-hydroxyvitamin D 1 alpha-hydroxylase (1-hydroxylase) and 24-hydroxylase activities, and an increase in plasma GH level. These parameters leveled off or fell over the dose range 1-2 micrograms/g E2 but there was evidence of a second peak in 1-hydroxylase activity at 6 micrograms/g E2. At this high dose rate, the plasma Ca level rose to 8 mM, as it does in the laying hen; 24-hydroxylase activity, growth rate, and plasma GH and plasma PRL levels all decreased. It was concluded that the dose response to estrogen in the growing chick is not linear and, in the case of 1-hydroxylase activity, may even be biphasic.  相似文献   
1000.
D Brewster 《Tropical doctor》1989,19(3):100-4 contd
With proper nursing care and procedures, small hospitals in rural areas of developing countries can provide good neonatal care and achieve perinatal mortality rates comparable to those found at teaching hospitals. The 1st ingredient of adequate neonatology is the establishment of proper regimens for feeding, observation, and resuscitation of newborns. Even in areas where the majority of births take place at home, good neonatal care is possible as long as local risk factors are identified, all newborns are screened for these factors, and at-risk infants are referred for treatment. Factors that place infants at risk include birthweight under 2 kg or above 4 kg, delivery before 34 weeks' gestation, respiratory distress, severe birth asphyxia or trauma, jaundice, prolonged rupture of the membranes, infant not sucking or febrile, convulsions, congenital malformations, and maternal disease. 4 areas require special knowledge on the part of health personnel: the asphyxiated infant, hypothermia, hypoglycemia, and neonatal sepsis. Health workers must be familiar with proper resuscitation techniques, especially avoidance of excessive suctioning of the pharynx, and be alert to signs of hypoxic ischemic encephalopathy. Premature, small, asphyxiated, and sick infants are at greatest risk of hypothermia, a condition that can be prevented by drying and wrapping newborns immediately. Providers should be alert to signs of hypoglycemia in infants of diabetic mothers, large-for-gestational-age babies, the low- birthweight infant, and sick babies. To prevent sudden infant deaths, all sick newborns should be treated for neonatal sepsis.  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