全文获取类型
收费全文 | 10679篇 |
免费 | 747篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 209篇 |
儿科学 | 294篇 |
妇产科学 | 326篇 |
基础医学 | 1327篇 |
口腔科学 | 205篇 |
临床医学 | 1195篇 |
内科学 | 2506篇 |
皮肤病学 | 128篇 |
神经病学 | 927篇 |
特种医学 | 465篇 |
外科学 | 1248篇 |
综合类 | 137篇 |
一般理论 | 9篇 |
预防医学 | 767篇 |
眼科学 | 197篇 |
药学 | 763篇 |
中国医学 | 3篇 |
肿瘤学 | 734篇 |
出版年
2022年 | 65篇 |
2021年 | 116篇 |
2020年 | 71篇 |
2019年 | 112篇 |
2018年 | 170篇 |
2017年 | 120篇 |
2016年 | 135篇 |
2015年 | 146篇 |
2014年 | 231篇 |
2013年 | 296篇 |
2012年 | 455篇 |
2011年 | 505篇 |
2010年 | 262篇 |
2009年 | 215篇 |
2008年 | 406篇 |
2007年 | 432篇 |
2006年 | 436篇 |
2005年 | 430篇 |
2004年 | 467篇 |
2003年 | 409篇 |
2002年 | 403篇 |
2001年 | 386篇 |
2000年 | 366篇 |
1999年 | 336篇 |
1998年 | 132篇 |
1997年 | 99篇 |
1996年 | 125篇 |
1995年 | 132篇 |
1994年 | 111篇 |
1993年 | 102篇 |
1992年 | 351篇 |
1991年 | 334篇 |
1990年 | 290篇 |
1989年 | 302篇 |
1988年 | 223篇 |
1987年 | 243篇 |
1986年 | 216篇 |
1985年 | 200篇 |
1984年 | 148篇 |
1983年 | 131篇 |
1982年 | 92篇 |
1980年 | 82篇 |
1979年 | 137篇 |
1978年 | 97篇 |
1977年 | 69篇 |
1975年 | 81篇 |
1974年 | 96篇 |
1973年 | 75篇 |
1972年 | 78篇 |
1971年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
21.
M P Paterson E B Hoffman P Roux 《The Journal of bone and joint surgery. British volume》1990,72(1):94-97
We reviewed the records of 1,156 patients treated for acute staphylococcal osteitis or septic arthritis over a 12-year period; 38 had been critically ill with evidence of multiple-organ involvement and 30 (79%) had features of the toxic shock syndrome. The mortality rate of these 38 patients was 13% and the long-term orthopaedic complication rate was 39%. The diagnosis and management of patients with osteitis or septic arthritis, disseminated staphylococcal disease, and the toxic shock syndrome is discussed. 相似文献
22.
23.
Elisabeth L George Leslie A Hoffman Arthur Boujoukos Thomas G Zullo 《American journal of critical care》2002,11(1):65-75
BACKGROUND: Many benefits and adverse effects of positioning are related to changes in ventilation and perfusion. A number of unique factors related to the allograft make the effects of positioning difficult to determine in single-lung transplant recipients. OBJECTIVES: To determine the effect of 3 body positions (supine, lateral with allograft lung down, and lateral with native lung down) on oxygenation and blood flow in single-lung transplant recipients in the 24 hours immediately after surgery. METHODS: A quasi-experimental repeated-measures design with stratified assignment to 1 of 3 different sequencing patterns for turning group was used to study 15 transplant recipients, 9 with emphysema and 6 with fibrosis. Oxygenation, ventilation, and blood flow measures (heart rate, blood pressure) were assessed after each turn. The effect of ischemic reperfusion injury was also explored. RESULTS: The oxygenation, ventilation, and bloodflow variables did not differ significantly across group, diagnosis, or time. Oxygenation variables measured when the allograft lung was dependent did not differ significantly from such measurements obtained when the native lung was dependent. CONCLUSIONS: No single position maximizes oxygenation in the immediate postoperative period in single-lung transplant recipients. Although a single standard protocol for positioning cannot be supported, the study does support the idea that transplant recipients can be safely turned in the immediate postoperative period without compromising oxygenation or hemodynamic status. 相似文献
24.
Low concentrations of ethanol (10-100 mM), added to assays in vitro, altered agonist (isoproterenol) binding to mouse cerebral cortical beta-adrenergic receptors in a reversible manner. Ethanol decreased the affinity of the high affinity form of the receptor for isoproterenol but had no effect on the affinity of the low affinity form of the receptor, the proportion of high and low affinity forms of the receptor, the total number of agonist-binding sites, or antagonist binding. The selective effect of ethanol on the properties of the high affinity agonist-binding site suggested that ethanol alters the characteristics of the complex of the receptor and Gs, the guanine nucleotide-binding protein. In cerebral cortical membranes of mice that had ingested ethanol chronically, isoproterenol binding data were best fit by a one-site model, even in the absence of guanine nucleotides. This change, when considered together with previously reported changes in adenylate cyclase activity, is reminiscent of heterologous desensitization of the beta-adrenergic receptor. Thus, both acute and chronic ethanol administration may produce changes in adrenergic function in brain. 相似文献
25.
Ectopic prolactin secretion from a gonadoblastoma 总被引:1,自引:0,他引:1
A 6.5-year-old girl developed isosexual, pseudoprecocious puberty secondary to a gonadoblastoma. The tumor was found to produce and secrete both immunoassayable and bioassayable prolactin based on immunohistochemical techniques and the presence of a prolactin gradient between the tumor vein and peripheral vein. The source of the prolactin was a Sertoli-like cell. Neither growth hormone nor growth hormone-releasing hormone was detected within the tumor. This case confirms the ectopic production of prolactin by neoplastic tissue. 相似文献
26.
1. Experiments were conducted to test the hypothesis that the responses of joint capsule mechanoreceptors better encode tissue stress or tissue strain. The experimental model was a small ligament from the cat knee capsule, which was stretched uniaxially in vitro. Experiments were done with either force or displacement as the controlled variable, and with steps, sinusoids, or pseudorandom Gaussian noise (PGN) as the input function. 2. The strength of coupling between neural discharge and both strain and stress was quantified during step experiments using linear correlation coefficients. The correlation between the frequency of neural discharge and stress was 0.93 +/- 0.09 (SD). The correlation between frequency of neural discharge and strain was -0.91 +/- 0.06. The magnitudes of these correlation coefficients were not significantly different. 3. The strength of coupling between neural discharge and both strain and stress during sinusoidal and PGN experiments was quantified by the use of an information theoretic statistic, transinformation. Out of 282 sinusoidal runs, transinformation between neural discharge and stress was significantly greater than transinformation between strain and neural discharge 241 times. Transinformation between strain and neural discharge was significantly greater 15 times. 4. During PGN experiments, transinformation between stress and neural discharge was greater than transinformation between strain and neural discharge in all 19 experimental runs. 5. Conditional transinformation between strain and neural discharge, given stress, was calculated for all sinusoidal and pseudorandom experiments. This statistic was greater than zero in 268 out of 289 experimental runs, indicating that a component of strain independent of stress is being signaled in the neural discharge. 相似文献
27.
B. Falk Y. Weinstein R. Dotan D. A. Abramson D. Mann-Segal J. R. Hoffman 《Scandinavian journal of medicine & science in sports》1996,6(5):259-264
Anaerobic power is characterized by a high degree of specificity regarding both the recruited muscles as well as the recruitment pattern. The popular Wingate Anaerobic Test (WAnT) is a cycling test that does not satisfy the need for a running-specific anaerobic test. We describe such a test, using a novel type of a commercially available treadmill (BRL 1800, Gymrol, France). The ergometer is equipped with a torque motor to neutralize the frictional resistance of the treadmill belt, and a hip-belt harness connected to a horizontal rod. Force applied to the harness is monitored by a strain gauge mounted on the rod, while vertical movement is monitored by a potentiometer at the posterior fixed end of the rod. These, in conjunction with the treadmill belt speed, enable the computation of horizontal and vertical power as well as the combined total output. Power is calculated both as 'peak' power (highest 2.5 s segment) and 'mean' power (20 s duration). Preliminary results of young athletes were generally consistent with the expected age-related changes in anaerobic power. Values obtained on the anaerobic treadmill were always higher than the corresponding WAnT values previously obtained in comparable age groups. The higher values were probably due to the larger muscle mass involved and the shorter peak and mean power durations (2.5 and 20 s versus 5 and 30 s in the WAnT, respectively). This test should enable not only running-specific anaerobic power monitoring but also the characterization of the relationship between the horizontal and vertical components of that power. 相似文献
28.
This paper compares the effects of parent-care associated with three living arrangements of elderly widowed mothers who were being helped by married daughters: elderly mother living separately; two-generation households (mothers, daughters, sons-in-law); and three-generation households (grandchildren present). Daughters whose mothers lived separately fared the best; their mothers were the most cognitively and functionally capable and the daughters reported the fewest negative effects of caregiving. Daughters in two-generation households provided the most care; their mothers were the oldest and most impaired. Since daughters in three-generation households reported more negative mental and emotional effects of care, the unique problems of caregiving in such households are discussed. 相似文献
29.
Metronidazole susceptibility testing for Helicobacter pylori: comparison of disk, broth, and agar dilution methods and their clinical relevance. 总被引:6,自引:2,他引:4 下载免费PDF全文
A J DeCross B J Marshall R W McCallum S R Hoffman L J Barrett R L Guerrant 《Journal of clinical microbiology》1993,31(8):1971-1974
Since the methods for metronidazole susceptibility testing of Helicobacter pylori have not been standardized or validated, we compared three methods that are used to test the metronidazole susceptibilities of 25 isolates of H. pylori. Specifically, we examined the methods of Steer's replicator agar dilution, tube broth microdilution, and modified Kirby-Bauer disk diffusion. The metronidazole disk zone sizes obtained by the disk diffusion method correlated well (r = 0.74) with the MICs obtained by the agar dilution method. Afterward, the disk diffusion method was used to characterize the metronidazole susceptibilities of 44 isolates of H. pylori. Dual therapy (bismuth and metronidazole) proved to be highly effective against metronidazole-susceptible strains (81.6% eradication rate) but fared poorly against resistant strains (16.7% eradication rate; P < 0.01). Using agar dilution testing, we validated the modified Kirby-Bauer disk diffusion method for metronidazole susceptibility testing of H. pylori and conclude that it is practical, accurate, and clinically applicable. 相似文献
30.
Growth hormone (GH) secretion declines during normal aging, resulting in lower serum insulin-like growth factor (IGF)-I levels. It has been proposed that many of the catabolic changes seen in normal aging, including osteoporosis and muscle atrophy, are in part caused by the decreased action of the GH-IGF-I axis. In addition, patients with GH deficiency have increased overall cardiovascular mortality. Several investigators have initiated GH treatment for elderly patients with relative hyposomatotropinemia. Initial reports suggest that GH can increase muscle mass, improve exercise tolerance, increase REM sleep and cause an enhanced sense of well-being. The basis for neuropsychiatric changes during GH therapy may be due to a direct CNS action of GH itself, to the increased IGF-I secretion which GH elicits, or to enhanced functioning of peripheral organ systems. Long-term studies will determine whether GH or IGF-I can exert a neurotrophic action in the aging brain. 相似文献