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   203410篇
  免费   4478篇
  国内免费   463篇
耳鼻咽喉   2859篇
儿科学   7971篇
妇产科学   6046篇
基础医学   26473篇
口腔科学   5828篇
临床医学   15690篇
内科学   36788篇
皮肤病学   4732篇
神经病学   11964篇
特种医学   10907篇
外国民族医学   98篇
外科学   29989篇
综合类   1542篇
一般理论   7篇
预防医学   16882篇
眼科学   4746篇
药学   14321篇
  2篇
中国医学   224篇
肿瘤学   11282篇
  2021年   428篇
  2018年   3728篇
  2017年   4026篇
  2016年   3358篇
  2015年   5063篇
  2014年   4565篇
  2013年   3748篇
  2012年   10291篇
  2011年   5216篇
  2010年   2479篇
  2009年   4097篇
  2008年   2411篇
  2007年   3205篇
  2006年   3425篇
  2005年   11486篇
  2004年   12924篇
  2003年   8480篇
  2002年   3691篇
  2001年   4597篇
  2000年   1944篇
  1999年   6031篇
  1998年   590篇
  1992年   7006篇
  1991年   7233篇
  1990年   7461篇
  1989年   7067篇
  1988年   6616篇
  1987年   6348篇
  1986年   6069篇
  1985年   5357篇
  1984年   3688篇
  1983年   2975篇
  1982年   1048篇
  1981年   789篇
  1980年   873篇
  1979年   3898篇
  1978年   2429篇
  1977年   1835篇
  1976年   1614篇
  1975年   2521篇
  1974年   3165篇
  1973年   2806篇
  1972年   2807篇
  1971年   2801篇
  1970年   2613篇
  1969年   2505篇
  1968年   2260篇
  1967年   2189篇
  1966年   1912篇
  1965年   1145篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
993.
The chromosome pattern of leukemias induced by gamma-irradiation in the translocation T190/tf and in the genetically related tf/tf strain was analyzed. The degree of variation in chromosome numbers was similar in both experimental groups. Karyotypically, the tumors of both strains showed slight and less frequent higher degree of variability. The most consistent karyotypic change was trisomy of chromosome 15, whose frequency was similar in both strains. In one of the leukemias a marker chromosome derived by translocation involving chromosome 15 was identified. Comparison of the breakpoint in this translocation with literature data on other translocations of chromosome 15 found in leukemias enabled narrowing the region on chromosome 15 containing the postulated genes essential for murine leukemogenesis. The incidence of leukemias was lower in the T190/tf translocation strain than in the tf/tf strain with normal karyotype.  相似文献   
994.
995.
The mechanisms by which adreno-corticoid hormones regulate Na+,K(+)-ATPase in adult kidney were studied in adrenalectomized (Adx) rats. Five days after adrenalectomy, Na+,K(+)-ATPase activity was significantly reduced in the renal cortex homogenate (C = 13.0 +/- 0.8 vs. Adx = 7.1 +/- 0.7 mumol Pi mg-1 protein h-1) and in renal microsomes (C = 30.3 +/- 1.9 vs Adx = 14.6 +/- 1.3 mumol Pi mg-1 protein h-1). Glucocorticoid replacement treatment of adrenalectomized rats with betamethasone (20 micrograms kg-1 body wt twice daily for 5 days) effectively counteracted the observed reduction in Na+,K(+)-ATPase activity. In cortical homogenate the protein level of alpha 1 and beta 1 subunits measured in immunoblots was not significantly different in Adx and control rats, indicating that 5 days after adrenalectomy the alpha 1 and beta 1 subunits were present in renal cortical cells to almost normal extent but could not be assembled into a transmembrane functional unit. In support of this conclusion we found that the protein level of both the alpha 1 and beta 1 subunits was significantly lower (P less than 0.001 for both subunits) in microsomes from Adx than in control rats. The mRNA abundance for alpha 1 and beta 1 subunits were not lower in Adx as compared to control rats 1 and 5 days after surgery. However, if Adx rats were given a single dose of betamethasone (600 micrograms kg-1 body wt), a significant 2-fold increase in both alpha 1 and beta 1 mRNAs was observed (P less than 0.05 for both subunits).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
996.
There is little doubt that preserving the spleen will contribute to a much more favourable outcome in patients undergoing splenic surgery, as a result of avoiding the well known risks of splenectomy. Among many operative methods described for splenic salvage, application of autologous fibrin glue (AFG) is particularly promising because of its unique characteristics. The use of AFG has been evaluated and its efficacy and tissue compatibility assessed in the treatment of splenic trauma in 15 partially splenectomized New Zealand White rabbits. The application of the AFG to the resected splenic surface achieved complete haemostasis in all animals. The animals were divided into four groups and were killed at varying intervals ranging from 24 h to 10 weeks. During re-exploration there was no evidence of recurrent bleeding and histopathological examination revealed progressive absorption of the AFG with a minimal inflammatory response. It is concluded that AFG is an effective haemostatic agent with good systemic and local compatibility and can be used in splenic salvage, which thereby avoids the use of non-autologous products with their risks of disease transmission.  相似文献   
997.
The paper is concerned with the results of a radioimmunoassay of the state of the renin-angiotensin-aldosterone system in patients with a neuroendocrine-metabolic type of the hypothalamic syndrome. They received pathogenetic therapy with peritol (an antiserotonin drug) or parlodel (a dopaminergic drug) during three months and routine therapy. The latter was not enough to return to normal the basal blood levels of aldosterone, reaction of the glomerular zone of the adrenocortical substance and the juxtaglomerular apparatus of the kidneys. Peritol therapy normalized the blood concentration of aldosterone; reactions of the glomerular zone of the adrenocortical substance and the juxtaglomerular apparatus to insulin hypoglycemia and furosemide acute testing improved considerably. After a course of parlodel therapy blood concentration of aldosterone got to normal, and reaction of the glomerular zone of the adrenocortical substance and the juxtaglomerular apparatus to insulin hypoglycemia was unchanged whereas it improved after furosemide testing.  相似文献   
998.
Determination of the ankle-shoulder index (ASI) was used in addition to clinical examination for the detection and monitoring of patients with obliterating arterial lesions of the legs. In individuals with suspected obliterating lesions, the ASI served as a criterion for the identification of normal, affected and high-risk groups and determined the strategy and duration of treatment and the follow-up schedule. ASI variation following surgery on arteries of the legs was an objective indicator of the efficiency of the operation and furnished indications for repeated surgical intervention to prevent reocclusion.  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