全文获取类型
收费全文 | 68191篇 |
免费 | 5996篇 |
国内免费 | 210篇 |
专业分类
耳鼻咽喉 | 545篇 |
儿科学 | 2666篇 |
妇产科学 | 1893篇 |
基础医学 | 9775篇 |
口腔科学 | 1256篇 |
临床医学 | 9538篇 |
内科学 | 13764篇 |
皮肤病学 | 1391篇 |
神经病学 | 7011篇 |
特种医学 | 1571篇 |
外国民族医学 | 4篇 |
外科学 | 6220篇 |
综合类 | 544篇 |
一般理论 | 66篇 |
预防医学 | 7909篇 |
眼科学 | 941篇 |
药学 | 3991篇 |
2篇 | |
中国医学 | 73篇 |
肿瘤学 | 5237篇 |
出版年
2024年 | 76篇 |
2023年 | 635篇 |
2022年 | 925篇 |
2021年 | 1934篇 |
2020年 | 1460篇 |
2019年 | 2163篇 |
2018年 | 2391篇 |
2017年 | 1867篇 |
2016年 | 2027篇 |
2015年 | 2146篇 |
2014年 | 2719篇 |
2013年 | 3877篇 |
2012年 | 5297篇 |
2011年 | 5317篇 |
2010年 | 3047篇 |
2009年 | 2721篇 |
2008年 | 4399篇 |
2007年 | 4484篇 |
2006年 | 4301篇 |
2005年 | 4053篇 |
2004年 | 3892篇 |
2003年 | 3538篇 |
2002年 | 3201篇 |
2001年 | 541篇 |
2000年 | 428篇 |
1999年 | 508篇 |
1998年 | 741篇 |
1997年 | 566篇 |
1996年 | 484篇 |
1995年 | 473篇 |
1994年 | 380篇 |
1993年 | 367篇 |
1992年 | 263篇 |
1991年 | 243篇 |
1990年 | 218篇 |
1989年 | 186篇 |
1988年 | 183篇 |
1987年 | 127篇 |
1986年 | 152篇 |
1985年 | 149篇 |
1984年 | 161篇 |
1983年 | 159篇 |
1982年 | 193篇 |
1981年 | 186篇 |
1980年 | 141篇 |
1979年 | 89篇 |
1978年 | 99篇 |
1977年 | 88篇 |
1976年 | 93篇 |
1974年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
M. Laurin Council Jennifer M. Gardner Cynthia Helms Ying Liu Lynn A. Cornelius Anne M. Bowcock 《Experimental dermatology》2009,18(5):485-487
Abstract: The risks of developing malignant melanoma (MM) include ultraviolet irradiation and genetic factors. To examine the contribution of rare and common variation within known MM genes in sporadic US MM patients, coding regions of known MM susceptibility genes [cyclin-dependent kinase inhibitor 2A ( CDKN2A ), cyclin-dependent kinase 4, melanocortin 1 receptor ( MC1R ) and tyrosinase ( TYR )] were resequenced in 109–135 MM cases. The significance of variants was examined by comparing their frequencies in 390 cancer-free controls. Potential deleterious mutations in CDKN2A were found in two patients and two others had variants of unknown significance. Cases were more likely than controls to harbour the MC1R 'R' variants known or predicted to alter its function ( P = 0.002), particularly the R160W variant ( P = 0.0035). The associated TYR R402Q variant (rs1126809*A) was found in 29% of cases, similar to what has been described previously. One MM patient with a family history of MM, who had developed other skin cancers, was homozygous for a novel TYR variant (P406L) of unknown significance. Hence, rare variants in TYR may be important risk factors for skin cancer. 相似文献
63.
64.
Marie Maguire 《British Journal of Psychotherapy》2005,22(1):3-20
ABSTRACT I explore a bisexual male patient's need to differentiate highly problematic'feminine'identifications - originating in childhood sexual abuse and impingement by men as well as women - from identifications with more admired aspects of his mother. My main focus is on the patient's sexual identity - the personal meaning he gave to being male - rather than on his bisexuality - his desire for both sexes. In psychoanalytic literature powerful opposite-sex identifications are usually associated either with psychotic confusion or celebrated as a source of psychic strength. The co-existence of problematic and highly valued cross-sex identifications is rarely discussed. I also look at how this patient re-negotiated his identity through the transference relationship with a female psychotherapist, given that his'masculinity'derived mainly from childhood experiences of 'stealing'his mother's phallic power. Through a wideranging theoretical review I conclude that we need to draw together opposing psychoanalytic perspectives about maternal and paternal power, opening up new ways of thinking about triangular relationships in the transference. 相似文献
65.
Skoug John W. Borin Marie T. Fleishaker Joseph C. Cooper Anne M. 《Pharmaceutical research》1991,8(12):1482-1488
The mechanism of release from sustained-release adinazolam mesylate tablets was assessed by the Higuchi equation and by analysis of drug release profiles through 60% released using the Peppas equation. Computed values of the diffusional exponent, n, ranged from 0.59 to 0.66. Values of n in this range are consistent with a mixed mechanism of release, with diffusion of drug through the hydrated polymer matrix and relaxation of this matrix being the principal processes controlling release. The rate of in vitro drug release was increased for half tablets relative to whole tablets and is attributed to an increase in the surface to volume ratio of half tablets of about 16%. This increase in surface-to-volume ratio of half tablets was reflected by an increase in the constant, k, from the Peppas equation of 20–23% and by an increase in the slope of Higuchi plots of 12–18% for four lots of tablets. In vivo/in vitro relationships from two bioavailability studies were thoroughly evaluated. Using either a linear or a quadratic relationship, an in vivo/in vitro correlation exists for sustained-release adinazolam mesylate tablets. 相似文献
66.
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
67.
68.
Cystic Fibrosis has effects on many body systems, including the skeletal system. In this case, we describe the impact of respiratory and endocrine disease on bone healing following orthopedic trauma in a 22-year-old woman. Limitations to mobility resulting from trauma complicated her respiratory condition. Disease-related effects on bone health and healing delayed her recovery from the trauma. It is important to recognize the multisystemic nature of CF, even when managing acute orthopedic injuries. 相似文献
69.
70.
Thomas J Beck Anne C Looker Firas Mourtada Maithili M Daphtary Christopher B Ruff 《Journal of bone and mineral research》2006,21(9):1425-1432
Age trends in proximal femur stresses were evaluated by simulating a fall on the greater trochanter using femur geometry from hip DXA scans of 5334 white men and women in the NHANES III survey. Expansion of femur outer diameter seems to counter net bone loss so that stresses remain similar across age groups, but stresses are higher in older women than in older men. INTRODUCTION: The age decline in hip BMD is caused by both bone loss and expansion of outer diameter that increases the region size over which mass is measured in a DXA scan. Because expansion has an opposing effect on structural strength, it may be a homeostatic adaptation to net bone loss to ensure that load stresses are kept within a narrow range. MATERIALS AND METHODS: Age trends in femur stresses were evaluated with an engineering beam simulation of a fall on the greater trochanter. Hip geometry was extracted from hip DXA scans using the Hip Structure Analysis (HSA) software on 2613 non-Hispanic white men and 2721 women from the third National Health and Nutrition Examination Survey (NHANES III). Using body weight as load, stresses were computed on the inferior-medial and superior-lateral femur neck at its narrowest point and the medial and lateral shaft 2 cm distal to the midpoint of the lesser trochanter. Stresses and the underlying geometries in men and women >50 years oaf age were compared with those 20-49 years of age. RESULTS: Compared with men <50 years of age, stresses in older men were 6% lower on both surfaces of the shaft, 4% lower on the inferior-medial neck, and not different on the superior-lateral neck. In women >50 years of age, stresses on the proximal shaft and inferior-medial neck remained within 3% of young values but were 13% greater on the superior-lateral neck. Neck stresses in young women were lower on the superior-lateral than the inferior-medial neck, but lateral stress increased to the level on the medial surface in older women. Stresses were higher in women than in men, with a greater gender difference in those >50 years of age. CONCLUSIONS: We conclude that femur expansion has a homeostatic effect in men and women that opposes bone loss so that stresses change little with age. Because expansion preserves stresses with progressively less bone mass, the process may reduce structural stability in the femoral neck under fall conditions, especially in the elderly female. 相似文献