全文获取类型
收费全文 | 950783篇 |
免费 | 68865篇 |
国内免费 | 1421篇 |
专业分类
耳鼻咽喉 | 13231篇 |
儿科学 | 24902篇 |
妇产科学 | 23834篇 |
基础医学 | 136142篇 |
口腔科学 | 28534篇 |
临床医学 | 82487篇 |
内科学 | 187059篇 |
皮肤病学 | 19734篇 |
神经病学 | 74218篇 |
特种医学 | 37860篇 |
外国民族医学 | 87篇 |
外科学 | 154873篇 |
综合类 | 18201篇 |
现状与发展 | 1篇 |
一般理论 | 244篇 |
预防医学 | 63142篇 |
眼科学 | 21785篇 |
药学 | 73906篇 |
3篇 | |
中国医学 | 2211篇 |
肿瘤学 | 58615篇 |
出版年
2018年 | 9306篇 |
2017年 | 7297篇 |
2016年 | 8114篇 |
2015年 | 9238篇 |
2014年 | 12456篇 |
2013年 | 18039篇 |
2012年 | 25017篇 |
2011年 | 26016篇 |
2010年 | 15338篇 |
2009年 | 14770篇 |
2008年 | 25385篇 |
2007年 | 26557篇 |
2006年 | 27370篇 |
2005年 | 26283篇 |
2004年 | 25351篇 |
2003年 | 24362篇 |
2002年 | 23867篇 |
2001年 | 55328篇 |
2000年 | 57103篇 |
1999年 | 47472篇 |
1998年 | 10965篇 |
1997年 | 9658篇 |
1996年 | 9763篇 |
1995年 | 9082篇 |
1994年 | 8416篇 |
1993年 | 7740篇 |
1992年 | 35813篇 |
1991年 | 34239篇 |
1990年 | 33090篇 |
1989年 | 32191篇 |
1988年 | 29289篇 |
1987年 | 28599篇 |
1986年 | 26594篇 |
1985年 | 25449篇 |
1984年 | 18071篇 |
1983年 | 15322篇 |
1982年 | 7929篇 |
1981年 | 6882篇 |
1979年 | 16014篇 |
1978年 | 10789篇 |
1977年 | 9218篇 |
1976年 | 8012篇 |
1975年 | 8782篇 |
1974年 | 10646篇 |
1973年 | 10028篇 |
1972年 | 9553篇 |
1971年 | 9030篇 |
1970年 | 8563篇 |
1969年 | 8079篇 |
1968年 | 7328篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The interpretation of the total phenytoin (PT) concentration can be problematic if valproic acid (VPA) is given as a comedication, because VPA displaces PT from the protein binding sites and can increase the free fraction of PT. In order to estimate the free or unbound PT concentration (PTf) from the total PT concentration (PTt) and VPA concentration, a nomogram was constructed and evaluated. Data of 84 patients on combined therapy with PT and VPA were used in drawing up the regression equation (PTf = 0.0792.PTt + 0.000636.PTt.VPA) from which the nomogram was constructed. The predictions were checked using another 33 patients whose serum concentrations were determined in the morning and in addition several times during the day. The results show that using this method the PTf concentrations can be accurately estimated from the PTt and VPA concentrations. 相似文献
992.
The antiparasitic drug, suramin, has antiproliferative effects in human carcinoma cells. It has been suggested that this occurs through blockade of growth factor-receptor interactions. Three types of evidence that suramin rapidly inhibits cellular respiration or disrupts cellular energy balance in intact cells of the human prostate carcinoma cell line, DU145, are presented. Beginning at approximately 10(-4) M, suramin rapidly causes dose-dependent inhibition of tetrazolium conversion by mitochondrial dehydrogenases in intact cells, demonstrating an inhibition of respiration. This effect is reversed by exchange with suramin-free media but not by pretreatment with serum, epidermal growth factor, insulin-like growth factor I, acidic and basic fibroblast growth factors, or calcium. Rhodamine 123 (10 micrograms/ml) uptake by mitochondria in intact DU145 cells is inhibited in the presence of 10(-3) M suramin. Treatment with 10(-4)-10(-3) M suramin causes the loss of rhodamine 123 from cells with mitochondria prestained with rhodamine 123, indicating that suramin is acting as an ionophore or respiratory poison. Also shown by electron microscopy are progressive toxic changes in mitochondria of DU145 cells within 1 h after treatment with 10(-4) M suramin. These data indicate that in intact DU145 cells 10(-4) M suramin rapidly disrupts cellular energy balance or respiration as seen by three studies of mitochondrial state. Disruption of energy balance or respiration represents a likely antiproliferative mechanism, as is thought to be a primary mechanism for the action of suramin in parasitic diseases. This proposed mechanism of action for suramin can explain the most prominent observed clinical toxicities of nephrotoxicity, adrenal toxicity, coagulopathy, and demyelinating neuropathy. 相似文献
993.
994.
995.
996.
Teriparatide vs. calcitonin in the treatment of Asian postmenopausal women with established osteoporosis 总被引:4,自引:0,他引:4
J. S. Hwang S. T. Tu T. S. Yang J. F. Chen C. J. Wang K. S. Tsai 《Osteoporosis international》2006,17(3):373-378
This study compared the clinical efficacy, safety, and tolerability of daily subcutaneous injections of teriparatide and salmon
calcitonin in the treatment of postmenopausal women with established osteoporosis in Taiwan. This 6-month, multicenter, randomized,
controlled study enrolled 63 women with established osteoporosis. They were randomized to receive either teriparatide 20 μg
or calcitonin 100 IU daily in an open-label fashion. Lumber spine, femoral neck, total hip bone mineral density (BMD), and
biochemical markers of bone turnover were measured, and adverse events and tolerability were recorded. The results at 6 months
showed that patients using teriparatide had larger mean increases in spinal BMD than those who used calcitonin (4.5% vs. 0.1%),
but the BMD changes in these two groups at the femoral neck and the total hip were not significant. There were also larger
mean increases in bone markers in the teriparatide group than in the calcitonin group (bone specific alkaline phosphatase
142% vs. 37%; osteocalcin 154% vs. 23%). We conclude that teriparatide has more positive effects on bone formation than salmon
calcitonin, as shown by the larger increments of lumbar spine BMD and bone formation markers, and caused only mild adverse
events and no significant change in liver, kidney or hematological parameters. Compared with the published global results,
teriparatide seems to be equally effective and safe to use in this Asian population. 相似文献
997.
998.
Derick T Wade 《British medical journal》2005,330(7489):468-471
999.
1000.
A T Lee 《Aviation, space, and environmental medicine》1991,62(2):158-161
In-flight encounters with hazardous weather represent one of the most significant safety issues in civil aviation operations. Aircrew judgment is often cited as the probable cause of incidents and accidents involving weather, although lack of information is also a factor. The present study examines how information, presented at different times and in different forms, affects the awareness and decision-making behavior of aircrews in a flight simulation study of a recent microburst/windshear incident. In order to examine the influence of enhanced information transfer on aircrew behavior, intracrew communications and approach-to-land decisions were evaluated with conventional ATC communications and with automated cockpit alerting and display of weather information. Results of the study revealed that aircrews provided only with conventional ATC transmissions of weather information had difficulty discriminating conditions conducive to microburst events from less hazardous windshear events. Improved situation awareness for microburst events was found when ground-based convective weather information was provided in real time to aircrews. Avoidance decision-making was found to be less efficient with conventional ATC alert transmissions when compared to the performance of crews provided with a visual display of microburst events. The importance of information transfer on aircrew situation awareness and decision-making in hazardous weather avoidance is discussed. 相似文献