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   11867篇
  免费   1240篇
  国内免费   70篇
耳鼻咽喉   185篇
儿科学   463篇
妇产科学   286篇
基础医学   1380篇
口腔科学   161篇
临床医学   1255篇
内科学   2470篇
皮肤病学   238篇
神经病学   1389篇
特种医学   265篇
外国民族医学   55篇
外科学   1400篇
综合类   82篇
一般理论   13篇
预防医学   1375篇
眼科学   334篇
药学   1029篇
中国医学   23篇
肿瘤学   774篇
  2024年   29篇
  2023年   301篇
  2022年   285篇
  2021年   575篇
  2020年   344篇
  2019年   366篇
  2018年   517篇
  2017年   479篇
  2016年   477篇
  2015年   444篇
  2014年   616篇
  2013年   773篇
  2012年   950篇
  2011年   943篇
  2010年   596篇
  2009年   575篇
  2008年   704篇
  2007年   725篇
  2006年   693篇
  2005年   582篇
  2004年   559篇
  2003年   471篇
  2002年   422篇
  2001年   71篇
  2000年   34篇
  1999年   74篇
  1998年   90篇
  1997年   61篇
  1996年   56篇
  1995年   58篇
  1994年   40篇
  1993年   35篇
  1992年   24篇
  1991年   19篇
  1990年   19篇
  1989年   16篇
  1988年   18篇
  1987年   12篇
  1986年   10篇
  1985年   8篇
  1984年   5篇
  1983年   9篇
  1982年   10篇
  1981年   18篇
  1980年   9篇
  1979年   5篇
  1978年   5篇
  1976年   5篇
  1974年   7篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Aim: The aim of the study was to investigate whether salivary mineral content may be associated with bone status in women after menopause. Material and methods: The study group consisted of 125 postmenopausal women aged 64.3 ± 6.9 yr, derived from the epidemiological SilesiaOsteoActive Study. All participants underwent hip and spine bone densitometry using dual energy X-ray absorptiometry, dental examination, and saliva content analysis. Data for salivary pH, copper, calcium, phosphorus, and zinc concentrations were evaluated. Results: Mean femoral neck bone mineral density (BMD) was 0.739 ± 0.118 g/cm2, total hip BMD 0.891 ± 0.14 g/cm2, and spine BMD 0.868 ± 0.14 g/cm2. Salivary pH was significantly lower in women with spinal osteoporosis defined as T-score below ?2.5, compared to individuals with normal BMD (pH: 6.65 ± 0.67 vs 6.96 ± 0.58, p < 0.05). There was a significant though weak inverse correlation between Ca concentration in saliva and femoral neck BMD (r = ?0.23, p < 0.05). Conclusions: High salivary calcium content and low salivary pH may be indicative of low hip and decreased spine BMD, respectively. These associations may reflect demineralization process (calcium redistribution) influencing bone, and a negative effect of acidity on mineral tissues, although causal pathway remains not clear.  相似文献   
53.
54.
55.
56.
57.
A prospective study of biochemical changes after vertical banded gastroplasty for morbid obesity, in 94 patients (10 males and 84 females, ages ranging from 18 to 59 years) has been carried out. Liver function tests and electrolyte estimations were performed preoperatively, during hospitalisation for surgery, at 6 weeks and at 6 months postoperatively, and demonstrated no significant changes in liver function in these patients 6 months after surgery. The study concludes that there is no increase in the risk of liver damage or electrolyte disturbance after vertical gastroplasty, but that there may be subtle hepatic changes present as gall bladder disease developed in 18 patients postoperation (19%).  相似文献   
58.
59.
The central action of the potential antidepressant drug pizotifen (Sandomigran) was studied in mice, rats and rabbits. Pizotifen in doses up to 10 mg/kg i.p. was ineffective in classic tests for antidepressant activity. It neither antagonized the effects of reserpine in rats (hypothermia, ptosis) nor potentiated the effects of amphetamine (in mice and rats), nialamide or L-dopa (in mice) on locomotor activity. However, its antidepressant activity was found in the despair test in rats.On the other hand, pizotifen inhibited the head twitch reaction induced by L-5-hydroxytryptophan in mice (ED50=0.009 mg/kg, i.p.) and by 5-methoxytryptamine (+tranylcypromine) in rats (ED50=0.45 mg/kg, i.p.). It also antagonized tryptamine-induced clonic convulsions of fore-paws in rats (ED50=0.35 mg/kg, i.p.), and in doses of 5–10 mg/kg s.c. inhibited hyperthermia produced by LSD in rabbits. Finally, pizotifen (0.1–0.3 mg/kg, i.v.) inhibited or abolished LSD- or quipazine-induced stimulation of the hind limb flexor reflex of spinal rats; the above effect was not due to noradrenolytic action of the drug. These results suggest that pizotifen strongly blocks the central postsynaptic serotonin receptors.  相似文献   
60.
PURPOSE: ZD6126 is a novel vascular targeting agent currently undergoing clinical evaluation. It acts by destabilizing the microtubulin of fragile and proliferating neoendothelial cells in tumors. The drug leads to blood vessel congestion, the selective destruction of the vasculature, and extensive necrosis in experimental tumors. The aim of the study reported here was to assess the ability of dynamic contrast enhanced magnetic resonance imaging (MRI) to measure the antivascular effects of ZD6126 in tumors. EXPERIMENTAL DESIGN: The work was carried out in mice bearing C38 colon adenocarcinoma and in patients with advanced cancers. MRI was performed before and 6 h (human tumors) or 24 h (C38 tumors) after i.v. drug administration. Contrast agent (gadolinium diethylenetriaminepentaacetate) enhancement was characterized by the initial area under the gadolinium diethylenetriaminepentaacetate uptake versus time curve (IAUC). IAUC reflects blood flow, vascular permeability, and the fraction of interstitial space. RESULTS: The median IAUC was reduced in all C38 tumors after ZD6126 administration [by 6-48% at 50 mg/kg (n = 3)], 58-91% at 100 mg/kg (n = 4), and 11-93% at 200 mg/kg (n = 6). In contrast, the administration of vehicle only led to no consistent change in median IAUC (n = 4). The ZD6126-induced changes in median IAUC appeared to be dose dependent (P = 0.045). No ZD6126-induced changes were apparent in murine muscle. Similar effects were seen in preliminary data from human tumors (11 tumors studied, 9 patients). At doses of 80 mg/m(2) and higher, the median IAUC post-ZD6126 treatment was reduced in all of the tumors studied (8 tumors, 6 patients) to 36-72% from the baseline value. There was a significant trend of increasing reductions with increasing exposure (P < 0.01). No drug-induced changes in human muscle or spleen IAUC were apparent. The reproducibility of the median IAUC parameter was investigated in patients. In 19 human tumors (measured in 19 patients) inter- and intratumor coefficients of variation were 64 and 18%. CONCLUSIONS: The contrast enhanced-MRI measured median IAUC is a useful end point for quantifying ZD6126 antivascular effects in human tumors.  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