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   5881篇
  免费   259篇
  国内免费   25篇
耳鼻咽喉   186篇
儿科学   125篇
妇产科学   40篇
基础医学   629篇
口腔科学   102篇
临床医学   364篇
内科学   1296篇
皮肤病学   214篇
神经病学   504篇
特种医学   226篇
外科学   848篇
综合类   40篇
预防医学   146篇
眼科学   46篇
药学   543篇
中国医学   20篇
肿瘤学   836篇
  2022年   31篇
  2021年   105篇
  2020年   56篇
  2019年   59篇
  2018年   63篇
  2017年   66篇
  2016年   61篇
  2015年   66篇
  2014年   104篇
  2013年   137篇
  2012年   222篇
  2011年   220篇
  2010年   142篇
  2009年   147篇
  2008年   212篇
  2007年   272篇
  2006年   246篇
  2005年   198篇
  2004年   273篇
  2003年   238篇
  2002年   233篇
  2001年   240篇
  2000年   271篇
  1999年   261篇
  1998年   70篇
  1997年   68篇
  1996年   65篇
  1995年   60篇
  1994年   62篇
  1993年   42篇
  1992年   187篇
  1991年   168篇
  1990年   152篇
  1989年   157篇
  1988年   136篇
  1987年   135篇
  1986年   141篇
  1985年   87篇
  1984年   81篇
  1983年   65篇
  1982年   36篇
  1979年   49篇
  1978年   30篇
  1975年   32篇
  1972年   31篇
  1971年   30篇
  1969年   33篇
  1968年   30篇
  1967年   40篇
  1966年   36篇
排序方式: 共有6165条查询结果,搜索用时 31 毫秒
71.
Zusammenfassung Mit Hilfe der kultivierten Fibroblasten aus Hautbiopsiematerial gelingt es, vor dem Auftreten anderer biochemischer Veränderungen zu klären, ob in einer mit Cystinose belasteten Familie ein junger Säugling, der noch keine klinischen Symptome bietet, an Cystinose leidet. Das Cystin erreicht in den Fibroblasten Cystinosekranker Konzentrationen von etwa 5–11 Mol1/2 Cystin/g Protein, während normale Fibroblasten nur Spuren von Cystin enthalten. Damit ist eine verläßliche Methode zur Frühdiagnose gegeben, die eine diätetische Therapie zu einem Zeitpunkt erlaubt, wo die irreversible Tubulopathie noch gering ist.
Summary It is possible to diagnose cystinosis in young infants from families, where cystinosis is known, by culturing fibroblasts from skin biopsy material before any biochemical or clinical symptoms are evident. Fibroblasts from patients suffering from cystinosis show a high content of about 5–11 Mol1/2 cystine/g protein, while normal fibroblasts only have traces of cystine.This is a very reliable method for early diagnosis and dietetic therapy can be started before any damage has been done to the tubuli.
  相似文献   
72.
73.
The behavior of hydridonickel coordination compounds as catalysts for the oligomerization and polymerization of butadiene in various solvents was studied. In the presence of alcohol bis(tricyclohexylphosphine)chlorohydridonickel ( 4 , X = Cl) (HNiCl[P(C6H11)3]2) catalyzes the linear dimerization. With hydridotetrakis(phosphite)nickel(1+) ( 2 ) ([HNi{P(OR)3}4]+), which is prepared from tetrakis(phosphite)nickel ( 1 ) (Ni[P(OR)3]4) and trifluoroacetic acid, dimerization occurs in sec-alcohol but there is no reaction in tert-alcohol. The main product is 2-methylenevinylcyclopentane ( 8 ). The other products are 4-vinylcyclohexene ( 10 ), 1,5-cyclooctadiene ( 5 ), 1,3,7-octatriene ( 7 ) and 1,3,6-octatriene ( 9 ). The hydridonickel coordination compound, prepared with inorganic acids, does not afford the dimers but the 1,4-trans polymer.  相似文献   
74.
We report on a 9-year-old boy with radioulnar synostosis, short stature, microcephaly, soliosis, and mental retardation. We propose that he has a new syndrome. © 1995 Wiley-Liss, Inc.  相似文献   
75.
Candidate cytomegalovirus strain for human vaccination.   总被引:15,自引:0,他引:15       下载免费PDF全文
A strain of human cytomegalovirus called Towne was isolated in WI-38 human fibrolast cell cultures from the urine of an infected infant. It was then passaged 125 times in WI-38, including three clonings, and a pool was prepared in the same cell substrate for use as a potential live attenuated vaccine. The Towne virus has a broad antigenicity and cross-reacts with the AD-169 strain. Several markers of the Towne virus were found which differentiated it from fresh isolates. One of these was resistance of the former to trypsin. The Towne virus was tested for freedom from oncogenicity or other harmful effects in preparation for tests in humans.  相似文献   
76.
77.
To examine the development of T cells within an allogeneic or xenogeneic environment, we engrafted the fetal thymus from AKR mice or F344 rats under the kidney capsule of SCID mice (mTG and rTG mice). T lymphopoiesis developed in SCID mice 2 months after transplantation, although the ratio of CD4/CD8 in both experimental groups was different from that of normal control. T cells in mTG mice did not show in vitro proliferation or cytotoxicity against either host-type C.B-17 (H-2d) or donor-type AKR (H-2k) cells, while they exerted potent activities against third-party BIO (H-2b) cells. In contrast, T cells in rTG mice exhibited proliferation against both host-type C.B-17 and donor-type F344 rat cells. Consistently, graft-vs.-host disease symptoms developed in these mice and histological examination showed impressive infiltration of lymphocytes into the skin or into the mucosal layers of the stomach. Activated state of T cells in rTG mice was also evidenced by the positive expression of interleukin-2 receptor. Taken together, fetal thymus appears to contain progenitor cells which are sufficient for in vivo reconstitution of T lymphopoiesis, but species-specific environment is important for the induction of tolerance. In mTG mice, Vβ6+ T cells reactive to donor Mlsa determinants and Vβ3+ T cells reactive to host Mlsc determinants were deleted, suggesting that tolerance was regulated mainly by clonal deletion. By contrast, Vβ11+ T cells reactive to Mlsf determinants were not deleted possibly due to the lack of their ligands.  相似文献   
78.
Denervation of dopaminergic neurons by intra nigral injection of 6-hydroxydopamine (6-OHDA) increased nerve growth factor (NGF) content in the cortex and hippocampus, both of which are innervated by cholinergic neurons. The increase continued during an observation period of 0.5-28 days after the lesion. The time course of changes in NGF content was quite different from that of cholinergic neuron denervation. The decreased dopamine content produced in the striatum by 6-OHDA injection was not recovered during the observation period. These results suggest that dopaminergic neuron damage may affect NGF synthesis.  相似文献   
79.
Kawasaki disease (KD) is an acute illness of early childhood characterized by prolonged fever, diffuse mucosal inflammation, indurative oedema of the hands and feet, a polymorphous skin rash and nonsuppurative lymphadenopathy. The histopathological findings in KD comprise panvasculitis with endothelial necrosis, and the infiltration of mononuclear cells into small and medium-sized blood vessels. The levels of many proinflammatory cytokines, chemokines and adhesion molecules can be elevated in sera from children with KD at the acute stage. Although many immunological studies on KD involving peripheral blood have been reported, the data obtained remain controversial. This review focuses on the immune response of peripheral blood lymphocytes and monocytes/macrophages during acute KD.  相似文献   
80.
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