全文获取类型
收费全文 | 3209篇 |
免费 | 223篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 120篇 |
妇产科学 | 34篇 |
基础医学 | 366篇 |
口腔科学 | 38篇 |
临床医学 | 271篇 |
内科学 | 722篇 |
皮肤病学 | 32篇 |
神经病学 | 131篇 |
特种医学 | 142篇 |
外科学 | 494篇 |
综合类 | 60篇 |
一般理论 | 1篇 |
预防医学 | 309篇 |
眼科学 | 152篇 |
药学 | 335篇 |
中国医学 | 6篇 |
肿瘤学 | 218篇 |
出版年
2023年 | 26篇 |
2022年 | 37篇 |
2021年 | 107篇 |
2020年 | 56篇 |
2019年 | 86篇 |
2018年 | 95篇 |
2017年 | 63篇 |
2016年 | 73篇 |
2015年 | 80篇 |
2014年 | 135篇 |
2013年 | 191篇 |
2012年 | 268篇 |
2011年 | 258篇 |
2010年 | 135篇 |
2009年 | 122篇 |
2008年 | 165篇 |
2007年 | 149篇 |
2006年 | 168篇 |
2005年 | 141篇 |
2004年 | 122篇 |
2003年 | 110篇 |
2002年 | 110篇 |
2001年 | 51篇 |
2000年 | 50篇 |
1999年 | 49篇 |
1998年 | 21篇 |
1997年 | 19篇 |
1996年 | 11篇 |
1993年 | 10篇 |
1992年 | 26篇 |
1991年 | 40篇 |
1990年 | 33篇 |
1989年 | 32篇 |
1988年 | 24篇 |
1987年 | 23篇 |
1986年 | 33篇 |
1985年 | 24篇 |
1984年 | 30篇 |
1983年 | 28篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 18篇 |
1978年 | 23篇 |
1977年 | 19篇 |
1976年 | 23篇 |
1975年 | 15篇 |
1974年 | 19篇 |
1973年 | 9篇 |
1972年 | 8篇 |
排序方式: 共有3443条查询结果,搜索用时 15 毫秒
1.
Venkatesan Chakrapani Thilakavathi Subramanian Pandara Purayil Vijin Ruban Nelson Murali Shunmugam Trace Kershaw 《Global public health》2020,15(3):438-451
ABSTRACTHIV-positive men who have sex with men (HIV+MSM) in India need culturally-relevant interventions to promote safer sex. We tested a multi-level intervention among HIV+MSM that targeted individual, interpersonal, and community factors, based on the Social-Personal and Social Ecological Models. We conducted a 2?×?2 factorial RCT with 119 HIV+MSM randomised to receive either an individual-level intervention (ILI) using motivational interviewing to promote safer sex, a community-level intervention (CLI) to strengthen community norms toward safer sex and reduce stigma among MSM communities, a multi-level intervention combining the individual- and community-level interventions (ILI?+?CLI), or standard-of-care control. Participants completed pre- and post-intervention assessments of a composite sexual risk score and a process evaluation to assess fidelity and satisfaction. Out of the 119 HIV+MSM, 106 (89.0%) completed pre- and post-intervention assessments. Generalised Estimating Equation models showed that both CLI (Incidence Rate Ratio [IRR]?=?.67, 95% CI .47 to .96) and ILI?+?CLI (IRR?=?.66, 95% CI .48 to .91) groups had a statistically significant decrease in sexual risk compared to the standard-of-care. The interventions had high levels of fidelity and satisfaction. This pilot RCT demonstrated feasibility and potential effectiveness of a multi-level intervention that addresses individual, interpersonal and community-level contributors of sexual risk among HIV+MSM. 相似文献
2.
3.
Fayiqa Ahamed Bahkir Srinivasan Subramanian Grandee 《Indian journal of ophthalmology》2020,68(11):2378
Purpose:Since the declaration of the lockdown due to COVID-19, the usage of digital devices has gone up across the globe, resulting in a challenge for the visual systems of all ages. The purpose of this study is to assess the impact of the lockdown on digital device usage, and consequently, the ocular surface health implications and circadian rhythm abnormalities related to digital eye strain.Methods:An open online survey was sent through various social media platforms and was open for a period of 2 weeks.Results:A total of 407 usable responses were obtained; the average age of respondents was 27.4 years. Typically, 93.6% of respondents reported an increase in their screen time since the lockdown was declared. The average increase in digital device usage was calculated at about 4.8 ± 2.8 h per day. The total usage per day was found to be 8.65 ± 3.74 hours. Sleep disturbances have been reported by 62.4% of people. Typically, 95.8% of respondents had experienced at least one symptom related to digital device usage, and 56.5% said that the frequency and intensity of these symptoms increased since the lockdown was declared.Conclusion:The study highlighted the drastic increase in use of digital devices after the initiation of the COVID-19 lockdown, and along with it, the slow deterioration of ocular health across all age groups. Awareness about prevention of digital eye strain should be stressed, and going forward, measures to bring these adverse effects to a minimum should be explored. 相似文献
4.
5.
6.
Barbara A. Bresnahan Christopher P. Johnson Matthew J. McIntosh Donald Stablein Sundaram Hariharan 《American journal of transplantation》2002,2(4):366-372
The optimal allocation of cadaveric kidneys for transplantation with reference to human leukocyte antigen (HLA) match and sharing these organs to a distant center remains controversial. The current analysis was performed using the United Network for Organ Sharing (UNOS) database for cadaveric kidney transplants (Tx) between 1988 and 1997. The graft survivals of zero-mismatch (matched) kidneys with the mate (mismatched) kidneys were compared. There were 2385 donors and 4770 Tx. Significant differences in recipient demographics between matched and mismatched Tx were: fewer African-American race (AA) in the matched group (9.0% vs. 21.9%), higher number of previous Tx (25.5% vs. 14.8%) and elevated mean cold ischemia time (24.0 vs. 22.2 h). Post-Tx dialysis requirements were similar (22.8% vs. 24.1%, p = 0.62) and matched kidneys had to travel more distance (920 vs. 232 miles). Using a Cox model, the matched group had a decreased relative hazard of graft failure of 23.0% (p = 0.0002) or 35% (p < 0.0001) with and without censoring for death. There was significantly better graft survival in the matched recipients in all pairs except AA (matched) and non-AA (mismatched). For older donors (> or = 50 years, n = 1508), the matched grafts survival was marginally significant (p =0.05). Matched kidneys have improved survival compared with the mismatched kidneys despite the longer distance traveled. The benefit of mismatched transplants was predominantly seen in non-AA. 相似文献
7.
8.
Sundaram Hariharan Eric P. Cohen Brahm Vasudev Rimas Orentas Raphael P. Viscidi Justin Kakela Brian DuChateau 《American journal of transplantation》2005,5(11):2719-2724
We evaluated twenty renal transplant subjects at various stages of BKV nephritis (BKVN) for BKV-specific IgG and IgM antibodies using ELISA technique and BKV-DNA using PCR. They were divided as early onset (n = 7), stabilizing (n = 3), resolved (n = 8) and late onset (n = 2) BKVN. BKV-specific antibodies and BKV-DNA were simultaneously determined. The mean BKV-specific IgG level in early onset and stabilizing BKVN were 64 and 39 EIA units, and were significantly lower than 138 EIA units seen in resolved BKVN, P = 0.007, P = 0.008. The mean BKV-specific IgM levels in stabilizing BKVN was higher than resolved BKVN (130 vs 51 EIA units), P = 0.006. Mean plasma BKV loads for each group were 955,925, 5642 and 42 copies/mL of plasma, respectively. Prospective study in six BKVN cases revealed mean IgG, IgM levels and BKV-DNA at the time of diagnosis of BKVN as 39, 110 EIA units and 586,758 copies/mL of plasma, respectively. After a mean period of 5.2 months, IgG level increased to 120 EIA units (p = 0.0058) and had no detectable viral copies in circulation. Recovery from BKVN and elimination of BKV is associated with the development of BKV-specific IgG antibodies and this provides insight into the role of humoral immunity to BKV in the pathogenesis of BKVN. 相似文献
9.
Antimurine antibody formation following OKT3 therapy 总被引:1,自引:0,他引:1
T J Schroeder M R First M E Mansour P E Hurtubise S Hariharan F C Ryckman R Munda D B Melvin I Penn W F Ballistreri 《Transplantation》1990,49(1):48-51
OKT3 is an IgG2a murine monoclonal antibody directed against the CD3 antigen receptor of human T lymphocytes. A major concern with OKT3 treatment in solid organ transplant recipients is the development of antimouse antibody, which may preclude retreatment with this agent. We have administered OKT3 on 215 occasions (150 renal, 34 hepatic, 26 cardiac, 5 pancreatic) in 179 patients between April 1982 and December 1988. The mean duration of treatment was 10.5 days (range, 2-22 days). Antimouse antibody data were analyzed on the most recent 133 treatment courses where the antibody status was available pretreatment. Determination of antimouse antibody production was elicited by ELISA technology at days 0, 7, 14, and 28 of OKT3 treatment. Patients were categorized according to the antibody response as follows: (a) absence of antibody; (b) low titer (1:100); or (c) high titer (greater than or equal to 1:1000). Our earlier experience has demonstrated that retreatment with OKT3 is successful in groups a and b. The development of antimurine antibodies was analyzed with regard to the following parameters: (1) The duration of OKT3 treatment; (2) treatment type (prophylactic, primary, or secondary); (3) primary treatment or retreatment; (4) concomitant immunosuppressive regimen (double or triple therapy); (5) dosage of concomitant immunosuppressive drugs; and (6) transplant organ type. The following results were obtained. (1) Duration of treatment had no effect on antibody production (11.0 days in antibody negative and 10.0 days in antibody positive). (2) There was no difference in antibody formation rates for the first treatment of OKT3 when it was used as prophylaxis (26%), primary (19%), or secondary (27%) therapy. (3) Antibody formation rate with first treatment was 29%; with retreatment, patients who were antibody negative following first treatment became positive in 28% of cases, and retreated patients who were low titer positive following first treatment converted to high titer in 57% of cases. (4) Antibody formation was higher in patients receiving double immunosuppressive therapy (36%) than in those receiving triple immunosuppressive therapy (21%) during OKT3 treatment. (5) Concomitant immunosuppression was lower in the antibody-positive group during OKT3 therapy: steroids, 61 mg/day vs. 52 mg/day; azathioprine, 89 mg/day vs. 66 mg/day; CsA, 317 mg/day vs. 186 mg/day. (6) Antibody formation rates were lower in non-renal transplants following first treatment with OKT3 (liver 17%, heart 17%, kidney 28%); this reflects the higher doses of concomitant immunosuppressive therapy used in nonrenal transplants.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
10.
Ectopic prolactin secretion from a gonadoblastoma 总被引:1,自引:0,他引:1
A 6.5-year-old girl developed isosexual, pseudoprecocious puberty secondary to a gonadoblastoma. The tumor was found to produce and secrete both immunoassayable and bioassayable prolactin based on immunohistochemical techniques and the presence of a prolactin gradient between the tumor vein and peripheral vein. The source of the prolactin was a Sertoli-like cell. Neither growth hormone nor growth hormone-releasing hormone was detected within the tumor. This case confirms the ectopic production of prolactin by neoplastic tissue. 相似文献