全文获取类型
收费全文 | 712篇 |
免费 | 66篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 25篇 |
妇产科学 | 5篇 |
基础医学 | 76篇 |
口腔科学 | 56篇 |
临床医学 | 84篇 |
内科学 | 139篇 |
皮肤病学 | 27篇 |
神经病学 | 8篇 |
特种医学 | 102篇 |
外科学 | 102篇 |
综合类 | 30篇 |
预防医学 | 53篇 |
眼科学 | 8篇 |
药学 | 38篇 |
中国医学 | 1篇 |
肿瘤学 | 37篇 |
出版年
2023年 | 4篇 |
2020年 | 5篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 19篇 |
2012年 | 16篇 |
2011年 | 25篇 |
2010年 | 20篇 |
2009年 | 30篇 |
2008年 | 15篇 |
2007年 | 37篇 |
2006年 | 21篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 18篇 |
2001年 | 23篇 |
2000年 | 24篇 |
1999年 | 13篇 |
1998年 | 26篇 |
1997年 | 38篇 |
1996年 | 34篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 19篇 |
1990年 | 11篇 |
1989年 | 29篇 |
1988年 | 27篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 16篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1969年 | 6篇 |
排序方式: 共有795条查询结果,搜索用时 15 毫秒
41.
Route of breathing in patients with asthma 总被引:4,自引:0,他引:4
STUDY OBJECTIVE: To determine the correlation between simple rating of condensation seen in the flex-tube connecting the heating and humidifying device used with the endotracheal tube and hygrometric parameters (absolute and relative humidity and tracheal temperature) measured by psychrometry. DESIGN: Prospective randomized clinical trial. SETTING: Medical ICU of Louis Mourier Hospital, Colombes, France, a university-affiliated teaching hospital. PATIENTS: Forty-five consecutive mechanically ventilated critically ill patients. INTERVENTIONS: Patients undergoing mechanical ventilation were randomly assigned to receive humidification with one of the four heat and moisture exchangers (HMEs) tested or with a conventional heated humidifier. MEASUREMENTS: The hygrometric performances of four HMEs (BB2215, BB50, and BB100 from Pall Biomedical, Saint-Germaine-en-Laye, France; and Hygrobac-Dar from Mallinckrodt, Mirandola, Italy) and a heated humidifier (Fisher & Paykel; Auckland, New Zealand) were studied after 3 h and also after 48 h of use for the Hygrobac-Dar and correlated to a clinical visual inspection rating the amount of condensation in the flex-tube of the endotracheal tube. RESULTS: A total of 95 measurements in 45 patients were performed. The best hygrometric parameters were obtained with the heated humidifier (p < 0.001). The Hygrobac-Dar yielded significantly higher values for both humidities and tracheal temperature than the other three HMEs (p < 0.001). The performance of Hygrobac-Dar was unchanged after 48 h of use. There was a significant correlation between the condensation seen in the flex-tube and the hygrometric parameters measured by psychrometry (absolute humidity, rho = 0.7; relative humidity, rho = 0.7; tracheal temperature, rho = 0.5, p < 0.0001). CONCLUSION: In mechanically ventilated ICU patients, visual evaluation of the condensation in the flex-tube provides an estimation of the heating and humidifying efficacy of the heating and humidifying device used, thus allowing the clinician bedside monitoring of airway humidification. 相似文献
42.
43.
G Caso P J Garlick M C Gelato M A McNurlan 《Clinical science (London, England : 1979)》2001,101(6):583-589
HIV infection has been shown to affect lymphocyte function and to reduce lymphocyte responsiveness in vitro to mitogenic stimulation, but little is known about lymphocyte metabolism in vivo and how it is affected during the course of the disease. This study investigated the metabolic activity of lymphocytes in vivo through the progression of HIV-associated disease. Lymphocyte protein synthesis was measured with L-[(2)H(5)]phenylalanine (45 mg/kg body weight) in healthy volunteers (n=7), in patients who were HIV-positive (n=7) but asymptomatic, and in patients with AIDS (n=8). The rates of lymphocyte protein synthesis [expressed as a percentage of lymphocyte protein, i.e. fractional synthesis rate (FSR)] were not altered in HIV-positive patients compared with healthy controls (7.9+/-1.28% and 9.1+/-0.53%/day respectively), but were significantly elevated in AIDS patients (14.0+/-1.16%/day; P<0.05). The serum concentration of the cytokine tumour necrosis factor-alpha (TNF-alpha) increased with the progression of the disease, and TNF-alpha levels were significantly higher in AIDS patients (6.81+/-0.88 ng/l) than in healthy controls (3.09+/-0.27 ng/l; P<0.05). Lymphocyte protein FSR was positively correlated with serum TNF-alpha concentration (r=0.55, P=0.009) and negatively correlated with CD4(+) lymphocyte count (r=-0.70, P=0.004). The elevation of lymphocyte protein synthesis in AIDS patients suggests a higher rate of turnover of lymphocytes. This may be associated with a generalized activation of the immune system, which is also reflected by the elevated serum TNF-alpha concentration in the late stages of HIV-associated disease. 相似文献
44.
45.
Biosynthesis and secretion of factor VII, protein C, protein S, and the Protein C inhibitor from a human hepatoma cell line 总被引:7,自引:0,他引:7
Using specific radioimmunoassays, 8 day cultures of Hep G2 cells were shown to contain in their supernatants 16, 74, and 828 ng/mL and in their cell lysates, 8, 55, and 48 ng/2 X 10(8) cells of factor VII, protein C, and protein S, respectively. These proteins and the protein C inhibitor were functionally active, and each of these activities was neutralized by their respective polyclonal antibodies. Although vitamin K had a modest effect, warfarin decreased the activity of secreted factor VII, protein C, and protein S by 50% to 90%. Protein C and protein S antigens were reduced three- to fourfold by warfarin. The protein C inhibitor antigen and activity were unaffected by vitamin K or warfarin treatment. Intrinsic labeling and immunoprecipitation indicated that factor VII, protein S, and the protein C inhibitor were secreted as 52,000, 77,000, and 58,000 molecular weight (mol wt) proteins, respectively. Protein C was secreted as a single-chain protein of about 65,000 mol wt, indicating that all of the vitamin K- dependent proteins are translated and secreted as single-chain molecules. Each of the four proteins studied represented their plasma protein counterparts structurally, functionally, and immunochemically. Thus, all of the known soluble components of the protein C pathway are produced by liver parenchymal cells. 相似文献
46.
47.
48.
49.
Nocardiosis of the lung: chest radiographic findings in 21 cases 总被引:4,自引:0,他引:4
Pulmonary manifestations of nocardial infection were present in 21 patients, with microbiologic proof in all and pathologic proof in 12. An analysis of the findings in these patients, combined with a review of previous reports of nocardiosis, suggests several important conclusions for radiologists. First, nocardiosis may occur in otherwise healthy persons but is most common in compromised patients, especially those being treated with anti-inflammatory agents, particularly corticosteroids, for chronic obstructive pulmonary disease and other systemic diseases. As pathologic manifestations are both suppurative and granulomatous, the chest radiographic manifestations are pleomorphic and not specific. Consolidations and large irregular nodules, often cavitary, are most common; nodules, masses, and interstitial patterns also occur. Pleural effusions are quite common, and lymph nodes may be enlarged. Difficulty and slowness of culture growth, along with the lack of a serologic test for nocardiosis, necessitate its inclusion in the differential diagnosis for both compromised and noncompromised patients in whom an apparent pulmonary infection cannot be rapidly diagnosed. 相似文献
50.