全文获取类型
收费全文 | 3767篇 |
免费 | 240篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 229篇 |
妇产科学 | 77篇 |
基础医学 | 284篇 |
口腔科学 | 278篇 |
临床医学 | 488篇 |
内科学 | 883篇 |
皮肤病学 | 26篇 |
神经病学 | 282篇 |
特种医学 | 300篇 |
外科学 | 381篇 |
综合类 | 117篇 |
一般理论 | 1篇 |
预防医学 | 239篇 |
眼科学 | 59篇 |
药学 | 247篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 125篇 |
出版年
2021年 | 46篇 |
2020年 | 33篇 |
2019年 | 60篇 |
2018年 | 55篇 |
2017年 | 54篇 |
2016年 | 44篇 |
2015年 | 66篇 |
2014年 | 88篇 |
2013年 | 92篇 |
2012年 | 155篇 |
2011年 | 150篇 |
2010年 | 128篇 |
2009年 | 105篇 |
2008年 | 116篇 |
2007年 | 107篇 |
2006年 | 123篇 |
2005年 | 122篇 |
2004年 | 86篇 |
2003年 | 108篇 |
2002年 | 91篇 |
2001年 | 92篇 |
2000年 | 97篇 |
1999年 | 102篇 |
1998年 | 114篇 |
1997年 | 111篇 |
1996年 | 112篇 |
1995年 | 75篇 |
1994年 | 77篇 |
1993年 | 69篇 |
1992年 | 70篇 |
1991年 | 82篇 |
1990年 | 72篇 |
1989年 | 94篇 |
1988年 | 82篇 |
1987年 | 99篇 |
1986年 | 77篇 |
1985年 | 90篇 |
1984年 | 53篇 |
1983年 | 63篇 |
1982年 | 51篇 |
1981年 | 34篇 |
1980年 | 44篇 |
1979年 | 51篇 |
1978年 | 50篇 |
1977年 | 28篇 |
1976年 | 29篇 |
1975年 | 29篇 |
1974年 | 32篇 |
1973年 | 27篇 |
1972年 | 38篇 |
排序方式: 共有4025条查询结果,搜索用时 0 毫秒
71.
72.
Critical discourse analysis was used to examine the visibility of nursing as a distinct discipline on the websites of academic nursing schools in Ireland. The analysis focused on the content of the schools’ websites, including the available undergraduate curricular materials. The websites of a purposive sample of academic nursing schools in Canada, Scandinavia, and Australia were also analyzed for comparative purposes. The texts revealed that the disciplinary distinctiveness of nursing was only minimally represented on nearly all of the Irish nursing schools’ websites. There was little evidence that nursing theory was informing the form and content of nursing programs. Instead, there was evidence of eclecticism in their form and content, with much reliance on imported knowledge from other disciplines. In contrast, nursing’s disciplinary specialism was coherently and clearly articulated in website texts of the selected Canadian, Scandinavian, and Australian schools. Representations of nursing on official websites convey important messages to prospective students and to the public about the self-conceptualisation of nursing, including its knowledge forms and knowledge claims. 相似文献
73.
74.
The use of metal on metal bearings in hip replacement has rapidly gained popularity during the last decade. This is probably due to: (a) the problems associated with wear of traditional bearing couples, (b) the increased numbers of younger patients undergoing hip replacement and (c) the superior theoretical tribiological characteristics. However, following this widespread adoption of the metal on metal prosthesis, there has been an exponential increase in the number of adverse reports detailing reactions to metal debris. This review describes the history, development and current evidence surrounding metal on metal hip replacement. 相似文献
75.
Jacey Nishiguchi Anusha McNamara Colleen S. Surlyn Kellene Vokaty Eagen Laura Feeney Vivian Lian David E. Smith 《Journal of viral hepatitis》2022,29(1):21-25
In 2016, an eConsult service was developed within a safety net health system to expand access to hepatitis C (HCV) treatment in the primary care setting. The eConsult system provides individualized treatment recommendations from specially trained primary care pharmacists and primary care physicians to primary care providers with less experience in the rapidly changing treatment of HCV. Since its launch, this service has had a large impact in expanding care to a largely homeless and low-income urban population within our health system. We now aim to evaluate its efficacy in curing HCV. In this retrospective cohort study, we describe rates of sustained virologic response 12 weeks after treatment completion (SVR12) for those who received primary care-based HCV treatment through the eConsult system with those who were treated in primary care independent of an eConsult from 2017 to 2019. We found there was no significant difference in the proportion of patients who achieved SVR12 between the two groups. Overall, >90% of patients who received treatment achieved SVR12. Approximately 40% of patients treated for HCV received an eConsult, suggesting utility of the eConsult in expanding access and coordinating treatment for patients within our network. 相似文献
76.
Doran AC Meller N McNamara CA 《Arteriosclerosis, thrombosis, and vascular biology》2008,28(5):812-819
The initiation of atherosclerosis results from complex interactions of circulating factors and various cell types in the vessel wall, including endothelial cells, lymphocytes, monocytes, and smooth muscle cells (SMCs). Recent reviews highlight the role of activated endothelium and inflammatory cell recruitment in the initiation of and progression of early atherosclerosis. Yet, human autopsy studies, in vitro mechanistic studies, and in vivo correlative data suggest an important role for SMCs in the initiation of atherosclerosis. SMCs are the major producers of extracellular matrix within the vessel wall and in response to atherogenic stimuli can modify the type of matrix proteins produced. In turn, the type of matrix present can affect the lipid content of the developing plaque and the proliferative index of the cells that are adherent to it. SMCs are also capable of functions typically attributed to other cell types. Like macrophages, SMCs can express a variety of receptors for lipid uptake and can form foam-like cells, thereby participating in the early accumulation of plaque lipid. Like endothelial cells, SMCs can also express a variety of adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 to which monocytes and lymphocytes can adhere and migrate into the vessel wall. In addition, through these adhesion molecules, SMCs can also stabilize these cells against apoptosis, thus contributing to the early cellularity of the lesion. Like many cells within the developing plaque, SMCs also produce many cytokines such as PDGF, transforming growth factor-beta, IFNgamma, and MCP-1, all of which contribute to the initiation and propagation of the inflammatory response to lipid. Recent advances in SMC-specific gene modulation have enhanced our ability to determine the role of SMCs in early atherogenesis. 相似文献
77.
78.
The surgical decision in tetralogy of Fallot: weighing risks and benefits with decision analysis 总被引:1,自引:0,他引:1
The preferred management of the symptomatic infant less than 2 years of age with tetralogy of Fallot remains unsettled. In this study decision analysis was used to assess the risks and benefits of three courses of action: (1) primary intracardiac repair; (2) palliative operation in infancy and delayed intracardiac repair; and (3) treatment with propranolol in infancy and delayed intracardiac repair. For each action the likelihood was determined of three possible outcomes for the patient: (1) death, (2) poor surgical result, or (3) good surgical result. Each outcome was associated with an estimated life expectancy. The best action was defined as that resulting in the longest life expectancy. With use of previously reported data and those from experience at one institution, a range of probabilities was estimated for death before operation, surgical mortality, success of propranolol treatment and hemodynamic result of operation. The choice of action was affected most by the mortality of primary intracardiac repair and the likelihood of a good hemodynamic result from intracardiac repair. Less important factors were the outcome of a palliative operation and the likelihood of success with propranolol therapy. It was found that in the institution studied if the mortality rate of primary intracardiac repair is 10 percent or less, intracardiac repair should be performed; otherwise propranolol treatment, which allows delay in intracardiac repair, should be selected. Both alternatives are preferable to palliative operation. With decision analysis, the clinician can use probabilities and life expectancy appropriate to a given clinical setting in determining the best management for the infant with tetralogy of Fallot. 相似文献
79.
Saskia PJ Verkleij Pim AJ Luijsterburg Sten P Willemsen Bart W Koes Arthur M Bohnen Sita MA Bierma-Zeinstra 《The British journal of general practice》2015,65(637):e530-e537
Background
The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear.Aim
To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis.Design and setting
Randomised controlled trial in general practice.Method
There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS).Results
Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = −0.2 to 1.3) and −0.2 (95% CI = −1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of −2.8 (95% CI = −10.7 to 5.1) and KOOS function of −2.7 (−10.6 to 5.0).Conclusion
Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%). 相似文献80.
Differential effects of nitric oxide on erythroid and myeloid colony growth from CD34+ human bone marrow cells 总被引:15,自引:0,他引:15
Nitric oxide (NO) is a reactive molecule with numerous physiologic and pathophysiologic roles affecting the nervous, cardiovascular, and immune systems. In previous work, we have demonstrated that NO inhibits the growth and induces the monocytic differentiation of cells of the HL- 60 cell line. We have also demonstrated that NO inhibits the growth of acute nonlymphocytic leukemia cells freshly isolated from untreated patients and increases monocytic differentiation antigens in some. In the present work, we studied the effect of NO on the growth and differentiation of normal human bone marrow cells in vitro. Mononuclear cells isolated from human bone marrow were cultured in semisolid media and treated with the NO-donating agents sodium nitroprusside (SNP) or S- nitroso-acetyl penicillamine (SNAP) (0.25 to 1 mmol/L). Both agents decreased colony-forming unit-erythroid (CFU-E) and colony-forming unit- granulocyte macrophage (CFU-GM) formation by 34% to 100%. When CD34+ cells were examined, we noted that these cells responded to SNP and SNAP differently than did the mononuclear cells. At a concentration range of 0.25 to 1 mmol/L, SNP inhibited the growth of CFU-E by 30% to 75%. However, at the same concentration range, SNP increased the number of CFU-GM by up to 94%. At concentrations of 0.25 to 1 mmol/L, SNAP inhibited the growth of CFU-E by 33% to 100%. At a concentration of 0.25 mmol/L, SNAP did not affect CFU-GM. At higher concentrations, SNAP inhibited the growth of CFU-GM. Although SNP increased intracellular levels of cGMP in bone marrow cells, increasing cGMP in cells by addition of 8-Br-cGMP (a membrane permeable cGMP analogue) did not reproduce the observed NO effects on bone marrow colonies. These results demonstrate that NO can influence the growth and differentiation of normal human bone marrow cells. NO (generated in the bone marrow microenvironment) may play an important role modulating the growth and differentiation of bone marrow cells in vivo. 相似文献