全文获取类型
收费全文 | 14119篇 |
免费 | 1570篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 372篇 |
妇产科学 | 361篇 |
基础医学 | 2355篇 |
口腔科学 | 254篇 |
临床医学 | 1547篇 |
内科学 | 3068篇 |
皮肤病学 | 191篇 |
神经病学 | 922篇 |
特种医学 | 953篇 |
外科学 | 1790篇 |
综合类 | 322篇 |
一般理论 | 7篇 |
预防医学 | 1403篇 |
眼科学 | 212篇 |
药学 | 1023篇 |
中国医学 | 12篇 |
肿瘤学 | 818篇 |
出版年
2021年 | 235篇 |
2020年 | 129篇 |
2019年 | 198篇 |
2018年 | 257篇 |
2017年 | 188篇 |
2016年 | 194篇 |
2015年 | 226篇 |
2014年 | 318篇 |
2013年 | 450篇 |
2012年 | 639篇 |
2011年 | 670篇 |
2010年 | 439篇 |
2009年 | 368篇 |
2008年 | 588篇 |
2007年 | 612篇 |
2006年 | 622篇 |
2005年 | 563篇 |
2004年 | 528篇 |
2003年 | 500篇 |
2002年 | 469篇 |
2001年 | 428篇 |
2000年 | 423篇 |
1999年 | 417篇 |
1998年 | 218篇 |
1997年 | 213篇 |
1996年 | 210篇 |
1995年 | 218篇 |
1994年 | 200篇 |
1993年 | 206篇 |
1992年 | 343篇 |
1991年 | 351篇 |
1990年 | 288篇 |
1989年 | 324篇 |
1988年 | 279篇 |
1987年 | 293篇 |
1986年 | 284篇 |
1985年 | 303篇 |
1984年 | 237篇 |
1983年 | 198篇 |
1982年 | 144篇 |
1981年 | 131篇 |
1980年 | 115篇 |
1979年 | 160篇 |
1978年 | 133篇 |
1977年 | 109篇 |
1976年 | 108篇 |
1975年 | 113篇 |
1974年 | 110篇 |
1973年 | 109篇 |
1972年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Clinical and laboratory findings are described in the case of a patient with a vein of Galen aneurysm who presented with recurrent aseptic meningitis for which no etiology could be identified. The patient subsequently developed thalamic and intraventricular hemorrhage associated with partial thrombosis of the dilated vein of Galen. Review of the literature revealed no previously reported association of these conditions. Recurrent cerebral venous thrombosis involving the fistula is hypothesized as the cause of repeated inflammatory reactions near the subarachnoid space. More extensive thrombosis may then have precipitated the hemorrhage. 相似文献
93.
P W Lepinski T S Thielke D M Collins A Hanson 《American journal of hospital pharmacy》1986,43(11):2771-2779
Unit dose and traditional drug distribution systems were compared in a 352-bed long-term-care facility by analyzing nursing time, medication-error rate, medication costs, and waste. Time spent by nurses in preparing, administering, charting, and other tasks associated with medications was measured with a stop-watch on four different nursing units during six-week periods before and after the nursing home began using unit dose drug distribution. Medication-error rate before and after implementation of the unit dose system was determined by patient profile audits and medication inventories. Medication costs consisted of patient billing costs (acquisition cost plus fee) and cost of medications destroyed. The unit dose system required a projected 1507.2 hours less nursing time per year. Mean medication-error rates were 8.53% and 0.97% for the traditional and unit dose systems, respectively. Potential annual savings because of decreased medication waste with the unit dose system were $2238.72. The net increase in cost for the unit dose system was estimated at $615.05 per year, or approximately $1.75 per patient. The unit dose system appears safer and more time-efficient than the traditional system, although its costs are higher. 相似文献
94.
L O''Donnell N O''Meara D Owens A Johnson P Collins G Tomkin 《Journal of the Royal Society of Medicine》1987,80(6):339-342
Changes in plasma catecholamines, lipoproteins and dietary intake were examined in 13 medical students during a 3-month period prior to their examinations, and in 12 controls. In the medical students mean +/- s.e.(mean) plasma cholesterol increased over the study period (3.98 +/- 0.16 v. 4.26 +/- 0.16 mmol/l, P less than 0.05) and this was reflected by a rise in low-density lipoprotein cholesterol (2.53 +/- 0.15 v. 2.71 +/- 0.17 mmol/l, P less than 0.05). Both supine adrenaline (0.45 +/- 0.05 v. 0.70 +/- 0.07 nmol/l, P less than 0.01) and noradrenaline (2.74 +/- 0.18 v. 3.40 +/- 0.31 nmol/l, P less than 0.05) increased over this period. Apart from a decline in the modest alcohol consumption (9.1 +/- 3.45 v. 2.6 +/- 1.4 g/day, P less than 0.02) there was no change in dietary intake in the medical students. There were no significant changes in plasma catecholamines, lipoproteins or dietary intake in control subjects over the study period. Changes in catecholamines and lipoproteins occurring in association with chronic psychological stress may contribute to the increased coronary heart disease mortality associated with Type A behaviour and stressful life events. 相似文献
95.
Randomised controlled trial of ranitidine versus omeprazole in combination with antibiotics for eradication of Helicobacter pylori. 总被引:2,自引:0,他引:2 下载免费PDF全文
T. C. Tham J. S. Collins C. Molloy J. M. Sloan K. B. Bamford R. G. Watson 《The Ulster medical journal》1996,65(2):131-136
This study compared high dose ranitidine versus low dose omeprazole with antibiotics for the eradication of H pylori. 80 patients (mean age 48 years, range 18-75) who had H pylori infection were randomised in an investigator-blind manner to either a two-week regime of omeprazole 20 mg daily, amoxycillin 500 mg tid and metronidazole 400 mg tid (OAM), or ranitidine 600 mg bd, amoxycillin 500 mg tid and metronidazole 400 mg tid (RAM), or omeprazole 20 mg daily and clarithromycin 500 mg tid (OC), or omeprazole 20 mg daily and placebo (OP). H pylori was eradicated in 6 of 19 patients in the OAM group (32%); 8 of 18 in the RAM group (44%), 4 of 15 in the OC group (27%); none of 18 in the OP group (0%). [< P0.005 for OAM, RAM, OC vs OP; P = N.S. between OAM, RAM, OC]. Overall metronidazole resistance was unexpectedly high at 58%. Eradication rates in metronidazole sensitive patients were 71% (5/7) and 100% (3/3) for OAM and RAM respectively. In conclusion, H pylori eradication rates using high dose ranitidine plus amoxycillin and metronidazole may be similar to that of low dose omeprazole in combination with the same antibiotics for omeprazole with clarithromycin. Overall eradication rates were low due to a high incidence of metronidazole resistance but were higher in metronidazole-sensitive patients. Even high dose ranitidine with two antibiotics achieves a relatively low eradication rate. These metronidazole-based regimens cannot be recommended in areas with a high incidence of metronidazole resistance. 相似文献
96.
Collins R 《Journal of family issues》1988,9(1):27-50
The stratification position of women is generally more complex than that of men. By the crucial class distinction of organizational power position, most women are either white-collar working class or blue-collar working class (order takers, not order givers). However, many women are involved in the Goffmanian labor of presenting the frontstage image of an organization, with the result that they have a somewhat more official attitude than the typical male working class, who are usually in a backstage position and hence are cynical of frontstage images. In the home, housewives do considerable surplus domestic labor devoted to the production of symbolic status rather than material reproduction. Women's paid employment is often concentrated in the formal organizations producing and distributing cultural goods and status-laden objects; the leisure activities of wives of the higher social classes also concentrate in realms of symbolic status, including the arts and charity. The class cultures of women can be explained by their structural locations. Modern capitalism itself may depend heavily on the dynamic of producing and consuming status-laden material objects and hence upon female activities. 相似文献
97.
The genetic basis of the duration and incidence of male wing fanning to pheromone in the pink bollworm moth,Pectinophora gossypiella (Saunders), was examined by artificial selection. Using a still-air bioassay, males from a laboratory colony were selected for increased duration of wing fanning when exposed to a 6535 blend of (Z,E)- and (Z,Z)-7,11-hexadecadienyl acetates. The mean (±SE) duration of wing fanning in the selected line increased from 5.4±1.4 to 17.4±2.7 s after six generations. The increase in wing fanning duration was the result of an increase in response duration among responders and not the percentage of males that responded. Realized heritability of wing-fanning duration was 0.16±0.02. The amount and ratio of pheromone produced by females in the male-selected line did not change.This research was supported in part by NSF Grant PCM-8309398 and a University of Massachusetts Biomedical Research Grant. 相似文献
98.
H King C Finch A Collins G Koki L F King P Heywood P Zimmet 《The Medical journal of Australia》1989,151(4):204-210
That Melanesians of non-Austronesian genetic ancestry may be relatively resistant to glucose intolerance was supported by the results of a study of two semitraditional non-Austronesian villages in the Papua New Guinean highlands in 1983, in which an absence of diabetes and a high degree of glucose tolerance and insulin sensitivity were observed. The second of this series of surveys was conducted in 1985 in three non-traditional communities: a periurban, non-Austronesian village in the highlands, and rural and periurban Austronesian villages in coastal locations. Although an absence of diabetes was demonstrated once again in the highlanders, these periurban subjects showed an unexpectedly high insulin response which may be a precursor of glucose intolerance. The notion that highland communities that are living in non-traditional circumstances in Papua New Guinea presently are in "metabolic transition" towards diabetes and other non-communicable diseases, if correct, is of importance to the public health of the nation. In the periurban, coastal-dwelling Austronesians, diabetes with severe hyperglycaemia was demonstrated, and there was some evidence of a secular trend towards increasing glucose intolerance. The two-hour plasma glucose concentrations were shown to be associated with obesity, modernity and Seventh-Day Adventist religious persuasion. However, important and unexplained differences in glucose tolerance remained between rural and periurban coastal dwellers after taking these factors into account. 相似文献
99.
J J Tjandra I S Russell J P Collins J T Andrews M Lichtenstein D Binns I F McKenzie 《Cancer research》1989,49(6):1600-1608
The presence of metastases in the regional lymph nodes is the major prognostic factor in breast cancer in the absence of overt distant metastases and is also an important indicator of the need for adjuvant therapy in "early" breast cancer. Currently, the accurate assessment of axillary lymph node status requires axillary dissection which has an associated morbidity. An alternative method of identifying patients who are "node positive" has been developed by means of immunolymphoscintigraphy with s.c. administered radioiodinated monoclonal antibody. The 131I-labeled anti-breast cancer antibody (RCC-1; 400 micrograms) and cold iodine-labeled "blocking" antibody (Ly-2.1; 2 mg which is nonreactive with breast cancer) were injected s.c. into both arms and scintigraphy images were obtained 16-18 h after the injection, using the axilla contralateral to the side of the breast cancer as the control. Studies were reported as positive (and therefore indicative of lymph node metastases) if the amount of background-subtracted radioactive count in the axilla of interest exceeded the normal side by a radio equal to or greater than 1.5:1.0 as assessed by computer analysis. In 38 of 40 patients the findings on scintigraphy were correlated with operative and histopathological findings on the axillary dissection specimen or cytological findings of fine needle aspiration of axillary lymph nodes. In a prospective study of 26 patients, the method is more sensitive (86%) and specific (92%) than preoperative clinical assessment (57% sensitivity, 58% specificity) in the detection of axillary lymph node metastases; and by combining both modalities of assessment, there was an improvement in the sensitivity (100%) but a deterioration in the specificity (50%). There was no significant complication from this essentially outpatient procedure and only 1 of 40 patients developed a human anti-mouse antibody response. This novel and safe method of imaging may become a most useful adjunct in the surgical management of breast cancer. 相似文献
100.
CpG DNA functions via the toll-like receptor-9 (TLR-9) receptor, inducing B cell proliferation and promoting immunoglobulin production. B cell responses to CpG DNA-containing immune complexes could be important in chronic autoimmunity and immune responses to bacterial components. Therefore, we investigated the potential synergy of CpG DNA-stimulation with FcgammaR clustering (CFR) on splenic B cell activity. CFR-induced splenocyte proliferation was significantly increased compared to treatment with CpG DNA alone. While the levels of interleukin-10 (IL-10) were increased in CpG DNA-treated splenocyte cultures, particularly following FcgammaRII/III-clustering, CFR treatment reduced IL-6 levels. B-cell maturation in culture was enhanced by CFR. Indeed, the frequency of IgG expressing cells after stimulation with CpG DNA was increased and was even higher after CFR stimulation. Furthermore, the frequency of plasma cell precursors was markedly increased by stimulation with CFR. Late splenic B cell subsets, transitional type 2 (T2) and mature (M) B cells, responded strongly to CpG DNA with proliferation and the response was enhanced by FcgammaR-clustering. Immature transitional type 1 (T1) B cells showed distinctly lower proliferative response to CpG DNA and very small effects of FcgammaR-clustering, despite similar expression of Fcgamma-receptors by all B cell subsets. In conclusion, these data show synergistic impact of CpG DNA and simultaneous FcgammaR-clustering on B cell proliferation and differentiation. 相似文献