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   27687篇
  免费   928篇
  国内免费   166篇
耳鼻咽喉   242篇
儿科学   518篇
妇产科学   459篇
基础医学   3547篇
口腔科学   448篇
临床医学   1608篇
内科学   6838篇
皮肤病学   368篇
神经病学   2481篇
特种医学   1065篇
外科学   4587篇
综合类   100篇
一般理论   5篇
预防医学   767篇
眼科学   613篇
药学   1657篇
  2篇
中国医学   69篇
肿瘤学   3407篇
  2023年   133篇
  2022年   266篇
  2021年   481篇
  2020年   269篇
  2019年   389篇
  2018年   440篇
  2017年   386篇
  2016年   435篇
  2015年   469篇
  2014年   604篇
  2013年   749篇
  2012年   1254篇
  2011年   1352篇
  2010年   800篇
  2009年   678篇
  2008年   1200篇
  2007年   1356篇
  2006年   1330篇
  2005年   1312篇
  2004年   1246篇
  2003年   1295篇
  2002年   1419篇
  2001年   740篇
  2000年   793篇
  1999年   756篇
  1998年   393篇
  1997年   306篇
  1996年   294篇
  1995年   271篇
  1994年   273篇
  1993年   274篇
  1992年   681篇
  1991年   609篇
  1990年   574篇
  1989年   580篇
  1988年   530篇
  1987年   524篇
  1986年   455篇
  1985年   455篇
  1984年   262篇
  1983年   222篇
  1982年   101篇
  1979年   237篇
  1978年   129篇
  1977年   109篇
  1975年   108篇
  1974年   102篇
  1973年   104篇
  1970年   104篇
  1969年   117篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
M MacPhee  C Mori 《Pediatric nursing》1991,17(5):438-42, 444
A neuromotor screening tool, The Chandler Movement Assessment of Infants Screening Test (CMAI-ST), was selected to teach nurses who care for premature infants about neuromotor development. After training with the CMAI-ST, the nurses were more adept at recognizing major components of neuromotor development.  相似文献   
63.
In a model of dyskinesia induced by the administration of iminodipropionitrile (IDPN) in the rat, we evaluated the effects of ceruletide, an analogue of cholecystokinin, on behavioral abnormalities and monoaminergic neuronal function. Vertical head twitching in the IDPN-treated animals was inhibited for over 5 h following a single subcutaneous dose of 160 micrograms/kg ceruletide. In animals dosed daily for 2 or 3 days, the number of head twitches at 24 h after the last dose was about one-third of the number before treatment. After repeated daily doses of ceruletide for 6 days, the number of head twitches was reduced to low levels and remained significantly below pretreatment levels until the 4th posttreatment day. These results indicate that the inhibition of dyskinesia by ceruletide was long-lasting. Assays of monoaminergic neurotransmitters and their metabolites in various brain regions indicate that an imbalance between dopaminergic and serotonergic neuronal systems plays a major role in the pathogenesis of the IDPN-induced dyskinesia, i.e. the ratio of (DOPAC+HVA)/5-HIAA was significantly greater in the striatum but significantly smaller in the hippocampus of the IDPN-treated vs normal animals. This initially abnormal ratio of (DOPAC+HVA)/5-HIAA in the striatum and hippocampus of IDPN-treated animals returned to normal following treatment with ceruletide, corresponding with the reduction of the head twitching. The alterations in monoaminergic neuronal function induced by repeated administration of ceruletide persisted for at least 3 days, even though its plasma half-life is several minutes. Ceruletide also exerted a marked effect on monoaminergic neuronal function in the IDPN-treated rats, in contrast to only a slight effect in normal animals.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
64.
To investigate the relationship between the effects of bone turnover and bone marrow cell development in bone cells, we developed a mouse voluntary climbing exercise model. Climbing exercise increased bone volume and transient osteogenic potential of bone marrow. This model would be suitable for investigating the mechanistic roles of mechanical loading. INTRODUCTION: The relationship between bone mass gain and local bone formation and resorption in mechanically loaded bone is not well understood. MATERIALS AND METHODS: Sixty-five C57BL/6J mice, 8 weeks of age, were assigned to five groups: a baseline control and two groups each of ground control and climbing exercise mice for 2 and 4 weeks. Mice were housed in a 100-cm tower and had to climb toward a bottle placed at the top to drink water. RESULTS: Compared with the ground control, bone mineral density of the left femur increased in the climbing mice at 4 weeks. At 2 and 4 weeks, bone formation rate (BFR/BS) of periosteal surface, the cross-sectional area, and moment of inertia were increased in the climbing mice, whereas BFR/BS and eroded surface (ES/BS) of endosteal surface did not differ. The trabecular bone volume (BV/TV) of the proximal tibia increased in climbing mice, and osteoclast surface (Oc.S/BS) and osteoclast number decreased at 2 weeks. At 4 weeks, there were increases in BV/TV and parameters of bone formation, including mineralized surface, mineral apposition rate, and bone formation rate. In marrow cell cultures from the tibia, the number of alkaline phosphatase+ colony forming units-fibroblastic and the area of mineralized nodule formation in climbing mice were increased, and the number of osteoclast-like TRACP+ multinucleated cells was lower at 2 weeks. At 4 weeks, these parameters recovered to the levels of the ground controls. CONCLUSION: Our results indicate that climbing increased trabecular bone volume and reduced bone resorption, with a subsequent increase in bone formation. Intermittent climbing downregulates marrow osteoclastogenic cells and upregulates osteogenic cells initially, but further exercise seemed to desensitize them. Cortical envelopes were enlarged earlier, but the response seems to differ from trabecular bone.  相似文献   
65.
Changes in the diffusion constant of water during reversible brain ischemia and cardiac arrest were monitored with a 10-s time resolution. Results (five cats, three rats) indicate that these changes are reversible and that the bulk of the changes are not caused by temperature or motion related to brain pulsations and blood flow. The rapid time course of the changes corresponds to the known time course for changes in energy state, signal transduction, and ionic homeostasis.  相似文献   
66.
The effect of diazepam on inbred mutant E1 mice, which develop convulsive seizures after repeated sessions of being tossed up, was examined. Acute administration of diazepam (32 mg/kg, i.p.) completely inhibited the convulsions. At that time, the dopamine level was increased in the cortex and hippocampus, and the norepinephrine level in the cerebellum was decreased. 5-Hydroxytryptamine levels were not changed. As for amino acids, the glutamine level increased and the levels of GABA, glutamic acid, aspartic acid, alanine and other amino acids were not changed.  相似文献   
67.
68.
In order to investigate whether a hypothalamic disorder cause hypogonadism in male prolactinomas, LH pulsatile secretion was studied in 13 male patients. Serum PRL levels ranged from 186 to 45,000 ng ml-1 before treatment, and all the tumors were macroadenomas. Reduced LH secretion was revealed in 5 of 13 patients, and FSH was reduced in 1 of 13. Serum testosterone (T) levels were lower than the normal limit in all the patients. HCG tests in 3 patients showed good responses, but the peak values of T were lower than those of normal men. LH pulsatilities were examined in 5 hyperprolactinemic patients before treatment, in 4 hyperprolactinemic patients after operation, and in 8 normoprolactinemic patients after operation and/or bromocriptine treatment. There was no significant difference of the mean LH values, the frequencies of LH pulses, and amplitudes among the hyperprolactinemic patients before operation (n = 5), the normoprolactinemic patients after operation (n = 8), and normal men (n = 7). From these results, it was evident that the hypothalamus and pituitary function of male prolactinomas were well preserved, in spite of higher serum PRL levels and larger tumor size than those reported in females. It is suggested that the main cause of hypogonadism in these patients is due to testicular dysfunction resulting from excessive serum PRL.  相似文献   
69.
Interhemispheric cysts, often associated with agenesis of the corpus callosum, are rare lesions demonstrating little uniformity of pathogenesis. Four large interhemispheric cystic lesions with several unique features are reviewed. Magnetic resonance imaging clearly showed agenesis of the corpus callosum and was useful in the diagnosis of interhemispheric cysts. The differential diagnosis of these lesions is discussed, along with therapeutic considerations.  相似文献   
70.
Amygdaloid-kindled rats received intravenous human copper-zinc superoxide dismutase (CuZn-SOD) either in free form or entrapped within liposomes (SOD-L), at 5, 10 or 20 mg/kg. The animals were stimulated at the generalized seizure-triggering threshold 5 min, 2 h and then every 24 h after the drug was given, until 5 consecutive stage 5 seizures were induced. Free CuZn-SOD had little or no effect. However, SOD-L, particularly at 10 mg/kg, had a prolonged anticonvulsant effect, although there was great individual variation in the onset and duration of seizure suppression. This effect of SOD-L may be due to the ability of liposomes to act as a depot for the sustained release of drugs.  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