全文获取类型
收费全文 | 20172篇 |
免费 | 2072篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 275篇 |
儿科学 | 792篇 |
妇产科学 | 554篇 |
基础医学 | 2851篇 |
口腔科学 | 634篇 |
临床医学 | 2435篇 |
内科学 | 3829篇 |
皮肤病学 | 361篇 |
神经病学 | 1695篇 |
特种医学 | 920篇 |
外科学 | 2348篇 |
综合类 | 594篇 |
一般理论 | 9篇 |
预防医学 | 2067篇 |
眼科学 | 288篇 |
药学 | 1570篇 |
中国医学 | 26篇 |
肿瘤学 | 1067篇 |
出版年
2021年 | 309篇 |
2020年 | 195篇 |
2019年 | 295篇 |
2018年 | 360篇 |
2017年 | 303篇 |
2016年 | 322篇 |
2015年 | 337篇 |
2014年 | 497篇 |
2013年 | 694篇 |
2012年 | 813篇 |
2011年 | 837篇 |
2010年 | 590篇 |
2009年 | 510篇 |
2008年 | 858篇 |
2007年 | 883篇 |
2006年 | 884篇 |
2005年 | 746篇 |
2004年 | 728篇 |
2003年 | 659篇 |
2002年 | 671篇 |
2001年 | 651篇 |
2000年 | 666篇 |
1999年 | 545篇 |
1998年 | 330篇 |
1997年 | 259篇 |
1996年 | 276篇 |
1995年 | 257篇 |
1994年 | 227篇 |
1993年 | 256篇 |
1992年 | 461篇 |
1991年 | 431篇 |
1990年 | 439篇 |
1989年 | 461篇 |
1988年 | 453篇 |
1987年 | 351篇 |
1986年 | 376篇 |
1985年 | 408篇 |
1984年 | 276篇 |
1983年 | 228篇 |
1982年 | 170篇 |
1981年 | 168篇 |
1979年 | 215篇 |
1978年 | 194篇 |
1977年 | 207篇 |
1976年 | 184篇 |
1975年 | 174篇 |
1974年 | 172篇 |
1973年 | 181篇 |
1972年 | 169篇 |
1971年 | 163篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
21.
Claudius E Robinson Venetia Rumnong Sarode Jorge Albores-Saavedra 《International journal of gynecological pathology》2003,22(3):220-225
Although tumors consisting of a combination of transitional cell carcinoma (TCC) and adenocarcinoma have been described in the endometrium, they have not been documented in the uterine cervix to our knowledge. Three such cervical cases are reported in this article. Three patients, whose ages ranged from 40 to 61 years, presented with vaginal bleeding and malignant cells on routine Papanicolaou smears. The initial diagnoses based on a biopsy specimen were poorly differentiated squamous cell carcinoma in two patients and adenocarcinoma with a solid component in the third patient. All patients underwent radical hysterectomy. The hysterectomy specimens each contained a polypoid endocervical mass with minimal invasion of the cervical stroma. On microscopic examination, each tumor consisted of a component of papillary TCC admixed with an adenocarcinoma of endometrioid type. Both carcinomatous components were immunoreactive for cytokeratin (CK) 7 but not CK20. The three patients were alive and disease-free from 10 months to 4 years postoperatively. Recognition of this unusual variant of cervical carcinoma is important to delineate its clinical and pathologic features and establish prognostic differences, if any, from other histologic subtypes of cervical carcinoma. Papillary TCC mixed with adenocarcinoma broadens the morphologic spectrum of transitional cell neoplasms of the uterine cervix. 相似文献
22.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
23.
24.
The purposes of the present study of chronic pain patients were to (a) assess whether cognitive and behavioral coping style is related to personality factors, (b) assess how coping styles differ across personality types, and (c) assess how outpatient interdisciplinary intervention affects the coping styles of various personality types. Four MMPI clusters (Depression/Pathological, V-type, Marginal Depression, and Marginal V-type) were derived using a hierarchical clustering procedure. Seventy subjects also completed the Coping Strategies Questionnaire before and after a 3-week outpatient pain management program. Pretreatment analyses indicated the Depression/Pathological and Marginal Depression groups used diverting attention less than either V-type group. The V-type group reported using praying/hoping significantly more than either of the marginal groups. At posttreatment the Depression/Pathological group used catastrophizing significantly more than either of the marginal groups. Results of pre-post analyses indicated that the Depression/Pathological group increased their use of diverting attention, reinterpreting pain sensations, and ignoring pain sensations, while decreasing catastrophizing. The V-type group increased their use of reinterpreting pain sensations, while decreasing praying/hoping and catastrophizing. Neither of the Marginal subtypes showed significant pre-post changes in coping strategies. These results suggest that different personality types use different pain coping strategies prior to multidisciplinary treatment. Groups showing more severe psychological distress, perhaps related to an underlying personality disorder, displayed greater changes in coping strategies with treatment, but remained more dysfunctional after treatment. These findings suggest that the alteration of coping strategies may be an important treatment effect needing more individualization to maximize treatment response.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
25.
26.
27.
28.
29.
Selective inhibition of T cell proliferation but not expression of effector function by human alveolar macrophages 总被引:1,自引:0,他引:1 下载免费PDF全文
BACKGROUND: Alveolar macrophages are thought to play an important part in regulating lung immune responses. While it is clear that human alveolar macrophages suppress T cell proliferation in vitro, the mechanisms by which this is achieved are not clear, nor is it known whether alveolar macrophages also inhibit other aspects of T cell function. METHODS: Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin or house dust mite allergen, and cultured with variable numbers of autologous alveolar macrophages obtained by bronchoalveolar lavage from 20 normal subjects. RESULTS: Alveolar macrophages induced a reversible inhibition of T cell proliferation in response to both mitogen and allergen stimulation, with the latter being considerably more susceptible to inhibition. This was achieved via heterogenous mechanisms, involving both soluble factors derived from alveolar macrophages and cell-cell contact. Despite inhibiting proliferation, alveolar macrophages had little or no effect on T cell calcium flux, the characteristic changes in CD3, CD2, CD28 and interleukin-2 (IL-2) receptor expression which accompany normal T cell activation, and IL-2 and interferon gamma secretion. In contrast, alveolar macrophages inhibited the tyrosine phosphorylation of proteins which may be involved in IL-2 receptor-associated signal transduction. CONCLUSIONS: The immunoregulatory properties of alveolar macrophages are relatively selective, allowing T cell activation and cytokine secretion while inhibiting T cell proliferation within the lung.
相似文献
相似文献
30.
T. F. Chen E. Robinson S. R. Payne E. Robinson 《Annals of the Royal College of Surgeons of England》1994,76(3):190-193
A catheter audit was performed at the Central Manchester Trust, which found that there was excessive ordering, inappropriate catheter selection by size, materials, balloon size and poor guidelines on catheter storage. From these findings and from the available literature, we have proposed guidelines on catheter selection with the aim of offering the best patient care and to provide cost efficiency which may be of benefit to other hospitals. 相似文献