全文获取类型
收费全文 | 175389篇 |
免费 | 11183篇 |
国内免费 | 1363篇 |
专业分类
耳鼻咽喉 | 2569篇 |
儿科学 | 3269篇 |
妇产科学 | 3926篇 |
基础医学 | 26237篇 |
口腔科学 | 3655篇 |
临床医学 | 16471篇 |
内科学 | 33194篇 |
皮肤病学 | 4748篇 |
神经病学 | 13136篇 |
特种医学 | 8919篇 |
外科学 | 24061篇 |
综合类 | 2261篇 |
现状与发展 | 5篇 |
一般理论 | 84篇 |
预防医学 | 10327篇 |
眼科学 | 4768篇 |
药学 | 14954篇 |
中国医学 | 1744篇 |
肿瘤学 | 13607篇 |
出版年
2023年 | 1077篇 |
2022年 | 3076篇 |
2021年 | 5283篇 |
2020年 | 2712篇 |
2019年 | 3957篇 |
2018年 | 4865篇 |
2017年 | 3577篇 |
2016年 | 4645篇 |
2015年 | 6249篇 |
2014年 | 7675篇 |
2013年 | 9245篇 |
2012年 | 13898篇 |
2011年 | 13482篇 |
2010年 | 7953篇 |
2009年 | 6690篇 |
2008年 | 10055篇 |
2007年 | 9847篇 |
2006年 | 9086篇 |
2005年 | 8589篇 |
2004年 | 7668篇 |
2003年 | 6623篇 |
2002年 | 5782篇 |
2001年 | 4656篇 |
2000年 | 4260篇 |
1999年 | 3442篇 |
1998年 | 1388篇 |
1997年 | 1052篇 |
1996年 | 1005篇 |
1995年 | 905篇 |
1994年 | 788篇 |
1993年 | 681篇 |
1992年 | 1679篇 |
1991年 | 1667篇 |
1990年 | 1439篇 |
1989年 | 1302篇 |
1988年 | 1228篇 |
1987年 | 1122篇 |
1986年 | 1079篇 |
1985年 | 939篇 |
1984年 | 681篇 |
1983年 | 600篇 |
1982年 | 425篇 |
1981年 | 396篇 |
1980年 | 352篇 |
1979年 | 539篇 |
1978年 | 440篇 |
1977年 | 396篇 |
1976年 | 355篇 |
1974年 | 371篇 |
1973年 | 334篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Traumatic cervical Brown-Sequard and Brown-Sequard-plus syndromes: the spectrum of presentations and outcomes. 总被引:1,自引:0,他引:1
Brown-Sequard syndrome (BSS) and Brown-Sequard-plus syndrome (BSPS) are characterised by asymmetrical paresis with hypalgesia more marked on the less paretic side. This study examined the clinical features of 38 patients (30 males and 8 females; mean age = 32 years) with traumatic cervical BSS or BSPS who underwent comprehensive inpatient rehabilitation. Twenty two injuries were caused by road traffic accidents, 8 by penetrating injuries, 5 by diving injuries, and 3 by other causes. After an average of 35 days in acute care and 79 days in rehabilitation, 37 patients had increased muscle strength, all 38 patients improved functional abilities, 29 patients walked independently, 34 had spontaneous bladder emptying, 36 were discharged home, and 14 were employed. Statistically significant increases (p less than 0.001) were made in modified Barthel index functional scores between admission and discharge. Patients with BSPS had a better prognosis than did those with 'pure' BSS. Patients with predominant upper limb weakness had more favourable outcomes than did those with predominant lower limb weakness. Few other potentially predictive demographic, injury, or neurological factors were associated with functional outcome. Patients with BSS or BSPS generally have a good prognosis for neurological and functional improvement. 相似文献
42.
Nitric oxide synthesis in the in vivo allograft response: a possible regulatory mechanism. 总被引:7,自引:0,他引:7
Activated macrophages are known to oxidatively metabolize L-arginine to nitric oxide and citrulline. We have recently shown that nitric oxide is a potent inhibitory molecule in the in vitro rat mixed-splenocyte culture, resulting in inhibition of proliferation and cytolytic T-cell induction. We undertook this study using the sponge matrix allograft model in the rat to determine whether nitric oxide plays a role in an in vivo allograft response. Our experiments showed that on day 6 after grafting, when cytolytic activity of allograft-infiltrating cells is first detected, allogeneic graft fluid contains higher levels of NO2-/NO3- (the stable endproducts of nitric oxide metabolism) than syngeneic graft fluid. Furthermore, evaluation of the supernatants of cultured graft-infiltrating cells revealed that allogeneic graft-infiltrating cells spontaneously produce higher amounts of nitric oxide than syngeneic graft-infiltrating cells. The nitric oxide production was inhibited in the presence of NG-monomethyl-L-arginine (NMA), the competitive inhibitor of nitric oxide production. Most of the nitric oxide production was observed in the adherent macrophage fraction of the allograft-infiltrating cells. When allograft-infiltrating cells were cultured in the presence of NMA, donor-specific cytolytic activity was observed, whereas allograft-infiltrating cells cultured in the absence of NMA showed no cytolytic activity. These data show that nitric oxide production may play an important regulatory role in the allograft response. 相似文献
43.
Functional renal insufficiency during long-term therapy with captopril and enalapril in severe chronic heart failure 总被引:4,自引:0,他引:4
Renal function was evaluated in 104 patients with severe chronic heart failure whom we treated with captopril or enalapril. Seventy patients showed no change or an improvement in renal function (group A), and 34 patients developed functional renal insufficiency (group B). Before converting-enzyme inhibition, group B patients received higher doses of furosemide (p less than 0.02) and had lower central venous pressures (p less than 0.05) than group A patients. After 1 to 3 months of converting-enzyme inhibition, an excessive reduction in left ventricular filling pressure (to less than 15 mm Hg) or mean arterial pressure (to less than 60 mm Hg) was noted in 28 of 34 (82%) patients in group B but in only 22 of 70 patients in group A (31%) (p less than 0.001). At the end of the study, drug-induced azotemia resolved after a reduction in the dosage of diuretics, despite unaltered treatment with captopril and enalapril. Hence, the deterioration of renal function after converting-enzyme inhibition in heart failure is not a toxic or immunologic reaction to therapy but results from specific hemodynamic events that can be ameliorated by sodium repletion. 相似文献
44.
45.
Chiropractic practitioners with accredited qualifications should have the right to diagnose, the right to operate diagnostic imaging machines, and the right to the title doctor and Yee San. This paper reviews chiropractic practice in Hong Kong as well as laws and provisions of the health professions namely Chiropractors Registration Ordinance, Medical Registration Ordinance, Dentists Registration Ordinance, Radiation Ordinance, and the provisions of codes of practice of Medical Laboratory Technologists and Radiographers. The need for amendments of relevant sections of health laws and provisions, which concern chiropractic rights, chiropractic practice, and clinical research of mechanical neuromusculoskeletal disorders is discussed. Patient privileges relevant to chiropractic practice are proposed. The Chinese title Yee San or Yee and the English title Doctor are generic terms. Hence, legally “Yee San” and “Doctor” should not be coined by medical practitioners and vice versa. Diagnostic imaging and laboratory procedures are essential for differential diagnosis of neuromusculoskeletal disorders, which may indicate or contraindicate the application of manipulation, and hence are essential for chiropractic practice and clinical research. Proposed amendments of the listed sections of the ordinances and provisions are also outlined. 相似文献
46.
47.
Immunoelectron microscopic studies of exfoliative iris tissue (seven specimens) revealed the presence of laminin in the fibrillar component of exfoliation material. The immunogold label was uniformly distributed on the exfoliation fibres. Deposition of laminin labelled exfoliation material in the dilator muscle was a noteworthy feature, as was an apparent depletion of laminin in the basement membranes of ostensibly unaffected vessels. In control iris tissue (five enucleated eyes) laminin was identified in the basement membrane round vascular contractile cells, but not beneath the endothelium. 相似文献
48.
Summary Gene therapy is the delivery of genetic material to specific cell types of an organism to alter its physiology or function. This technology is being explored as a means of treating diseases caused by deficiencies of hepatic gene products. The two diseases being used as models for hepatic gene therapy are classical phenylketonuria (PKU) and haemophilia B. Vectors derived from adenoviruses can be used to completely correct these diseases in animal models. The phenotypic correction generated in these studies is transient, and cannot be duplicated by vector readministration. The transient nature of transgene expression results from the destruction of the virally-transduced cells by a cellular immune response directed against the late viral gene products that are also expressed in the target cells. The inability to repeatedly administer virus is caused by a humoral immune response directed against viral proteins present at the time of infusion. If the host immune response is suppressed, transgene expression can persist for 6 months or more. These findings suggest that host immunomodulation in combination with further modification of the adenoviral vector to reduce or eliminate late viral gene expression may permit long-term expression of potentially therapeutic gene products in mammalian liver. 相似文献
49.
W W Wong W J Cochran W J Klish E O Smith L S Lee M L Fiorotto P D Klein 《European journal of clinical nutrition》1988,42(3):233-242
We estimated body fat in 20 normal adults (10 males and 10 females) from 18O- and 2H-dilution spaces and from the equations of Durnin & Womersley and Pollock, Schmidt & Jackson based on skinfold thickness measurements. Differences between methods for body fat estimation were found to be sex-dependent: subsequent analyses indicated significant differences between methods within each sex. Regardless of sex, the highest fat estimates were obtained with the 18O-dilution method, followed by those obtained with the 2H-dilution method or the Durnin & Womersley equation. The lowest fat estimates were obtained using the Pollock, Schmidt & Jackson equation. The 18O-dilution method and the Durnin & Wormersley anthropometric method are both suitable and appropriate for body fat estimation in adults studied under field conditions. 相似文献
50.
M E Lee 《Journal of the American Optometric Association》1988,59(7):567-571
Beta adrenergic blocking agents have gained wide acceptance among practitioners and patients alike as extremely useful drugs for the treatment of open-angle glaucoma. This new class of antiglaucoma agents usually is effective in reducing elevated intraocular pressure and is generally well tolerated. This paper is intended to provide an understanding of the ophthalmic beta adrenergic blocking agents to optometrists who are actively involved in the treatment of glaucoma and/or in the monitoring of glaucoma patients. The clinical pharmacology of the three FDA-approved beta blockers -- timolol, levobunolol, and betaxolol, is evaluated and the drugs are compared. 相似文献