全文获取类型
收费全文 | 7341篇 |
免费 | 447篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 241篇 |
妇产科学 | 200篇 |
基础医学 | 1112篇 |
口腔科学 | 62篇 |
临床医学 | 635篇 |
内科学 | 1568篇 |
皮肤病学 | 372篇 |
神经病学 | 536篇 |
特种医学 | 156篇 |
外国民族医学 | 6篇 |
外科学 | 1136篇 |
综合类 | 59篇 |
一般理论 | 15篇 |
预防医学 | 568篇 |
眼科学 | 122篇 |
药学 | 500篇 |
中国医学 | 6篇 |
肿瘤学 | 483篇 |
出版年
2022年 | 38篇 |
2021年 | 71篇 |
2020年 | 48篇 |
2019年 | 93篇 |
2018年 | 95篇 |
2017年 | 68篇 |
2016年 | 77篇 |
2015年 | 112篇 |
2014年 | 132篇 |
2013年 | 224篇 |
2012年 | 370篇 |
2011年 | 396篇 |
2010年 | 240篇 |
2009年 | 234篇 |
2008年 | 400篇 |
2007年 | 429篇 |
2006年 | 423篇 |
2005年 | 409篇 |
2004年 | 441篇 |
2003年 | 417篇 |
2002年 | 399篇 |
2001年 | 181篇 |
2000年 | 182篇 |
1999年 | 195篇 |
1998年 | 101篇 |
1997年 | 82篇 |
1996年 | 94篇 |
1995年 | 76篇 |
1994年 | 66篇 |
1993年 | 56篇 |
1992年 | 131篇 |
1991年 | 103篇 |
1990年 | 107篇 |
1989年 | 119篇 |
1988年 | 82篇 |
1987年 | 101篇 |
1986年 | 83篇 |
1985年 | 92篇 |
1984年 | 65篇 |
1983年 | 67篇 |
1982年 | 51篇 |
1981年 | 50篇 |
1980年 | 37篇 |
1979年 | 69篇 |
1978年 | 51篇 |
1977年 | 45篇 |
1976年 | 36篇 |
1975年 | 44篇 |
1973年 | 35篇 |
1971年 | 41篇 |
排序方式: 共有7814条查询结果,搜索用时 31 毫秒
1.
2.
3.
Adeline Tarantini Sylvie Huet Gérard Jarry Rachelle Lanceleur Martine Poul Ana Tavares Nádia Vital Henriqueta Louro Maria João Silva Valérie Fessard 《Environmental and molecular mutagenesis》2015,56(2):218-227
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
4.
5.
A simple circuit design is described which provides LED readout of transmitted and reflected pulsed rf power. The utility of monitoring these variables in physiological NMR studies is discussed. 相似文献
6.
Jean Marie Jully Marie Christine Béné Gérard Martin Gilbert Faure 《Journal of clinical periodontology》1986,13(3):223-227
The cellular infiltrate present in human diseased gingiva was analyzed in biopsies from 12 patients with gingivitis or periodontitis. The samples studied had been obtained in the course of surgery at inflammatory sites remaining after institution of periodontal treatment. Histological and immunological techniques were used to identify macrophages, B-cells, plasma-cells, T-cells and T cell subsets, as well as cells expressing class II HLA membrane antigens. T-cells appeared as the predominant population, but plasma-cells were also visualized in nearly all samples. Both OKT4+ and OKT8+ cells were seen in all cases, the latter being more numerous in periodontitis patients. Interdigitating-like cells were observed, positively labelled for class II antigens, as well as macrophages which were more numerous in periodontitis patients. These results suggest the participation of all components of the immune response in gingival disease, in a way resembling chronic recurrent inflammatory diseases. 相似文献
7.
Colonoscopy and bacteraemia: an experience in 50 patients 总被引:1,自引:0,他引:1
There is little consensus concerning the incidence of bacteraemia during colonoscopy and the need for antibiotic prophylaxis in susceptible patients. Hepatic abscesses in one patient which may have been related to prior colonoscopic examinations led the authors to carry out a prospective study of 50 patients undergoing colonoscopy. Multiple blood cultures were carried out to maximise the positive yield of transient bacteraemia and to attempt to determine the time when bacteraemia is most likely to occur. Five patients had positive blood cultures. In two patients S epidermidis was isolated, but only from the precolonoscopic blood sample. In three subjects enteric organisms were cultured from blood samples obtained during the procedure. In one of these three the same organism was cultured from the preendoscopic blood sample so that in only two patients (4%) could the bacteraemia be attributed to the colonoscopy. These results would suggest that the risk of bacteraemia during colonoscopy is low. 相似文献
8.
B Jouve F Collet R Cointe P Barragan P Bru M Metge A Vaillant A Elkouby C Malmejac R Gérard 《Archives des maladies du coeur et des vaisseaux》1989,82(3):337-343
Between 1977 and 1987, 27 consecutive patients (16 men, 11 women, mean age 66 years, range 54 to 75 years) with ventricular septal rupture complicating acute myocardial infarction underwent surgical repair. The purpose of this retrospective study was to analyse the post-operative mortality factors from clinical, haemodynamic and operative data in all patients and also from coronary angiographic data in 23/27 patients whose haemodynamic status allowed this type of exploration. Seventeen patients (63 p. 100) died during the first post-operative month, 10 survived and were discharged. Factors that influenced the prognosis were: (1) inferiorly-located necrosis associated with a 75 p. 100 mortality rate (9 out of 12 patients), as opposed to 53 p. 100 (8 out of 15 patients) with anterior necrosis; (2) right ventricular dysfunction, observed in 83 p. 100 of patients with inferior necrosis and 53 p. 100 with anterior necrosis, which was responsible for 7 out of 9 deaths in the inferior necrosis subgroup and contributed to 3 out of 8 deaths in the anterior necrosis subgroup; this established a cause-effect relationship between right ventricular function and the overmortality of patients with inferior necrosis; (3) independently of the haemodynamic status, two- and three-vessel lesions (56 p. 100 of all lesions) which had an 84 p. 100 mortality rate as opposed to 40 p. 100 with one-vessel lesions; (4) the presence of a state of shock which was associated with a 78 p. 100 mortality rate as opposed to 55 p. 100 in patients without shock. We conclude that when permitted by the patient's haemodynamic status coronary angiography should be part of the pre-operative evaluation to assess the operative risk and guide the surgical procedure. 相似文献
9.
10.
R M Sandford M J Bown R D Sayers J N London A R Naylor M J McCarthy 《European journal of vascular and endovascular surgery》2007,34(1):29-34
OBJECTIVES: Angioplasty is often used in the management of lower limb ischaemia and can reduce the need for infrainguinal bypass in some patients. There is an associated failure rate with this technique and bypass surgery is often used in this situation as a secondary limb salvage procedure. We aimed to evaluate the outcome of infrainguinal bypass grafting following failed attempt at angioplasty. METHODS: All cases of infrainguinal bypass at a single centre over a seven year period were identified and notes reviewed. Cases were divided into four groups according to their indication for surgery; acute ischaemia, chronic critical ischaemia, failed angioplasty and an 'other' group including aneurysmal disease and claudicants. The failed angioplasty group was compared with the other three groups. Survival analysis was performed using Kaplan Meier curves and groups compared in terms of long term patency and survival. RESULTS: Primary patency was 61.2% in the failed angioplasty group at 12 months compared with 60.6% in the other groups (P=1.11). There was also no significant difference in primary patency at 60 months (50% vs 40.6%, P=0.26). Survival at 12 months was also comparable between the groups (failed angioplasty group 74.2% compared with 77.3% in the other groups, P=0.662) as was 60 months survival (33.3% and 35.4% respectively, P=0.166). DISCUSSION: In this study, outcome of infrainguinal bypass following failed angioplasty was comparable to outcome of surgery performed for another indication. This paper supports the use of distal bypass surgery for limb salvage in cases where minimal access techniques have failed. 相似文献