全文获取类型
收费全文 | 7908篇 |
免费 | 586篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 238篇 |
妇产科学 | 235篇 |
基础医学 | 1181篇 |
口腔科学 | 140篇 |
临床医学 | 858篇 |
内科学 | 1613篇 |
皮肤病学 | 206篇 |
神经病学 | 762篇 |
特种医学 | 165篇 |
外科学 | 693篇 |
综合类 | 73篇 |
一般理论 | 9篇 |
预防医学 | 934篇 |
眼科学 | 119篇 |
药学 | 644篇 |
中国医学 | 19篇 |
肿瘤学 | 565篇 |
出版年
2024年 | 12篇 |
2023年 | 85篇 |
2022年 | 158篇 |
2021年 | 310篇 |
2020年 | 190篇 |
2019年 | 262篇 |
2018年 | 290篇 |
2017年 | 186篇 |
2016年 | 241篇 |
2015年 | 265篇 |
2014年 | 332篇 |
2013年 | 417篇 |
2012年 | 679篇 |
2011年 | 684篇 |
2010年 | 396篇 |
2009年 | 308篇 |
2008年 | 529篇 |
2007年 | 509篇 |
2006年 | 498篇 |
2005年 | 444篇 |
2004年 | 371篇 |
2003年 | 354篇 |
2002年 | 319篇 |
2001年 | 33篇 |
2000年 | 32篇 |
1999年 | 36篇 |
1998年 | 61篇 |
1997年 | 51篇 |
1996年 | 33篇 |
1995年 | 36篇 |
1994年 | 31篇 |
1993年 | 19篇 |
1992年 | 16篇 |
1991年 | 24篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 29篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 20篇 |
1980年 | 21篇 |
1979年 | 12篇 |
1977年 | 8篇 |
1974年 | 9篇 |
1973年 | 12篇 |
1928年 | 13篇 |
排序方式: 共有8530条查询结果,搜索用时 15 毫秒
41.
Kathleen Rooney Caroline Hunt Leanne Humphreys David Harding Miriam Mullen John Kearney 《Clinical psychology & psychotherapy》2005,12(2):97-111
Prior reports suggest an ambivalence regarding treatment in individuals with Post-Traumatic Stress Disorder (PTSD). A model that accommodates such ambivalence is the Transtheoretical Model of Behavior Change (TTM, also known as the Stages-of-Change Model). Fifty veterans presenting for treatment completed self-report measures (94% response rate) that assessed disorder variables and constructs relating to the TTM. While the relationships between the components of each specific construct were found to be consistent with the findings of other studies and a number of predicted relationships between variables were confirmed, many results were inconsistent with the TTM. Notwithstanding questions about the suitability of the self-report measures, the unique characteristics of the veteran sample and the small sample size, the results suggest that the assumptions of the TTM were not met in veterans with PTSD. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
42.
Andrade MM Tomé MF Santiago ES Lúcia-Santos A de Andrade TG 《Physiology & behavior》2003,78(1):125-133
We conducted a longitudinal study about daily variation of Wistar male rats' behavior in the elevated plus-maze (EPM) evaluated in the 1st, 2nd, 3rd, 6th, 12th, and 18th months of life. Animals were submitted to the plus-maze in 12 sessions at 2-h intervals (n=72, 6 per time point). Spontaneous rest-activity rhythm of four animals was assessed by observation of 24-h videotape records. Time series were analyzed by Cosinor method. Behavioral rates on the six occasions and in light and dark phases were compared by means of two-way ANOVA with repeated measures. Exploratory behavior in EPM was smaller in the light phase and in older animals. Higher values of open and closed arms exploration were observed in the first and third months of the dark phase, and in the first month of the light phase. Adjustment to the 24-h period was significant at all stages for rest-activity data, number of entries in closed arms, and time on center, and for three to five stages for open-arm exploration. In general, 24 h variability was more pronounced in younger animals compared with older ones. The present study showed that: (1). a significant amount of total variability of the behavioral indexes analyzed could be attributed to 24 h variation, (2). light/dark phases differences in EPM exploration were present at all developmental stages, (3). older Wistar rats explored less the EPM and were less active in their home cage compared with younger ones, and (4). behavioral indexes (EPM) decrease was phase related and partially related to a reorganization of rest-activity rhythm. 相似文献
43.
Donnadieu E Jouvin MH Rana S Moffatt MF Mockford EH Cookson WO Kinet JP 《Immunity》2003,18(5):665-674
Allergic reactions are triggered via crosslinking of the high-affinity receptor for immunoglobulin E, F(c)epsilonRI. In humans, F(c)epsilonRI is expressed as a tetramer (alphabetagamma(2)) and a trimer (alphagamma(2)). The beta subunit is an amplifier of F(c)epsilonRI surface expression and signaling. Here, we show that as a consequence of alternative splicing, the F(c)epsilonRIbeta gene encodes two proteins with opposing and competing functions. One isoform is the full-length classical beta, the other a novel truncated form, beta(T). In contrast to beta, beta(T) prevents F(c)epsilonRI surface expression by inhibiting alpha chain maturation. Moreover, beta(T) competes with beta to control F(c)epsilonRI surface expression in vitro. We propose that the relative abundance of the products of the beta gene may control the level of F(c)epsilonRI surface expression and thereby influence susceptibility to allergic diseases. 相似文献
44.
A STAT4-dependent Th1 response is required for resistance to the helminth parasite Taenia crassiceps 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rodríguez-Sosa M Saavedra R Tenorio EP Rosas LE Satoskar AR Terrazas LI 《Infection and immunity》2004,72(8):4552-4560
To determine the role of STAT4-dependent Th1 responses in the regulation of immunity to the helminth parasite Taenia crassiceps, we monitored infections with this parasite in resistant mice lacking the STAT4 gene. While T. crassiceps-infected STAT4(+/+) mice rapidly resolved the infection, STAT4(-/-) mice were highly susceptible to infection and displayed large parasite loads. Moreover, the inability of STAT4(-/-) mice to control the infection was associated with the induction of an antigen-specific Th2-type response characterized by significantly higher levels of Th2-associated immunoglobulin G1 (IgG1) and total IgE as well as interleukin-4 (IL-4), IL-10, and IL-13 than those in STAT4(+/+) mice, who produced significantly more gamma interferon. Furthermore, early after infection, macrophages from STAT4(-/-) mice produced lower levels of the pro-inflammatory cytokines IL-12, tumor necrosis factor alpha, IL-1 beta, and nitric oxide (NO) than those from STAT4(+/+) mice, suggesting a pivotal role for macrophages in mediating protection against cysticercosis. These findings demonstrate a critical role for the STAT4 signaling pathway in the development of a Th1-type immune response that is essential for mediating protection against the larval stage of T. crassiceps infection. 相似文献
45.
Lymphatic endothelial cell identity is reversible and its maintenance requires Prox1 activity 总被引:2,自引:0,他引:2
Nicole C. Johnson Miriam E. Dillard Peter Baluk Donald M. McDonald Natasha L. Harvey Sharon L. Frase Guillermo Oliver 《Genes & development》2008,22(23):3282-3291
The activity of the homeobox gene Prox1 is necessary and sufficient for venous blood endothelial cells (BECs) to acquire a lymphatic endothelial cell (LEC) fate. We determined that the differentiated LEC phenotype is a plastic, reprogrammable condition that depends on constant Prox1 activity for its maintenance. We show that conditional down-regulation of Prox1 during embryonic, postnatal, or adult stages is sufficient to reprogram LECs into BECs. Consequently, the identity of the mutant lymphatic vessels is also partially reprogrammed as they acquire some features typical of the blood vasculature. siRNA-mediated down-regulation of Prox1 in LECs in culture demonstrates that reprogramming of LECs into BECs is a Prox1-dependent, cell-autonomous process. We propose that Prox1 acts as a binary switch that suppresses BEC identity and promotes and maintains LEC identity; switching off Prox1 activity is sufficient to initiate a reprogramming cascade leading to the dedifferentiation of LECs into BECs. Therefore, LECs are one of the few differentiated cell types that require constant expression of a certain gene to maintain their phenotypic identity. 相似文献
46.
47.
Gastrointestinal mesenchymal tumors - immunophenotypic classification and survival analysis 总被引:8,自引:0,他引:8
Rudolph P Chiaravalli AM Pauser U Oschlies I Hillemanns M Gobbo M Marichal M Eusebi V Höfler H Capella C Klöppel G 《Virchows Archiv : an international journal of pathology》2002,441(3):238-248
The current definition of gastrointestinal tumors (GIST) as CD117-positive mesenchymal tumors of uncertain malignant potential fails to include a number of cases with similar histology. In an attempt to improve the classification of these neoplasms, we conducted an immunohistochemical analysis of 244 mesenchymal tumors with histological features of GIST. According to their immunophenotype, the tumors were classified as GISTs, which are characterized by CD117 (c-kit) expression; gastrointestinal CD117-negative CD34 positive stromal tumors (GINST); alpha-smooth muscle actin and/or desmin positive gastrointestinal leiomyogenic tumors (GILT); S-100 and glial fibrillary acidic protein positive gastrointestinal glial/schwannian tumors (GIGT); gastrointestinal neuronal/glial tumors (GINT), which are positive for S-100/glial fibrillary acidic protein plus neuronal/glial markers; and gastrointestinal fibrous tumors (GIFT), which are only vimentin positive. The most common type of tumors were GIST, followed in order of frequency by GINST, GILT, GIGT, GIFT, and GINT. GISTs did not show any preferential location, whereas GINSTs occurred almost exclusively in the stomach and duodenum, and GILTs preferentially in the large intestine. Over a median follow-up period of 71 months, malignant behavior, i.e., metastatic spread, was observed in all tumor types except GINTs. Malignancy was associated with distal gut location, high mitotic activity, large tumor size, and nuclear pleomorphism, though none of these criteria alone discriminated between benign and malignant. Kaplan-Meier analysis of disease-specific survival showed significant differences in the long-term outcome of the newly defined subgroups. We conclude that, despite strong morphological similarities, gastrointestinal mesenchymal tumors are heterogeneous in their immunophenotype and biology. 相似文献
48.
Otto C Gasser M Waaga-Gasser AM Rohde AC Lenhard M Jost S Gassel HJ Ulrichs K Timmermann W 《Human immunology》2002,63(10):880-887
It has been extensively documented the role of the indirect pathway of allorecognition in allograft rejection. However, recent data demonstrate that the manipulation of this pathway could be also sufficient to promote prolongation of allograft survival. In the present study we evaluated the effect of preoperative immunization with the WF-specific MHC class II peptides RT1.D2 and RT1.B2 in combination with low-dose CsA from days 0 to 7 (5 mg/kg/day) and from days 8 to 30 (1 mg/kg/day) after WF small bowel transplantation. Seven days before and on the day of transplantation, LEW recipients were immunized with the two WF MHC class II peptides RT1.B2 and RT1.D2. The CsA monotherapy induced an allograft survival of 49.3 +/- 6.1 days. MHC class II peptide immunization had a limited effect on allograft survival for RT1.D2 (47.1 +/- 3.8 days) and induced prolongation of allograft survival for RT1.B2 (73.6 +/- 34.6 days). This effect seems to be based on the absence or silence of RT1.B2-reactive T cells and rejection seems to be correlated with the presence of RT1.B2-specific T cells in the late phase. Therefore, the combination of RT1.B2 with low-dose CsA shifts the immunological response and protects small bowel allograft rejection. 相似文献
49.
Allicin stimulates lymphocytes and elicits an antitumor effect: a possible role of p21ras 总被引:7,自引:0,他引:7
Patya M Zahalka MA Vanichkin A Rabinkov A Miron T Mirelman D Wilchek M Lander HM Novogrodsky A 《International immunology》2004,16(2):275-281
Allicin, the main organic allyl sulfur component in garlic, exhibits immune-stimulatory and antitumor properties. Allicin stimulated [(3)H]thymidine incorporation in mouse splenocytes and enhanced cell-mediated cytotoxicity in human peripheral mononuclear cells. Multiple administration (i.p.) of allicin elicited a marked antitumor effect in mice inoculated with B-16 melanoma and MCA-105 fibrosarcoma. The immune-stimulatory and antitumor effects of allicin are characterized by a bell-shaped curve, i.e. allicin at high, supra-optimal concentrations is less effective or inhibitory. Allicin induced activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in human peripheral mononuclear cells, and also in wild-type Jurkat T-cells. Allicin failed to activate ERK1/2 in Jurkat T cells that express p21(ras), in which Cys118 was replaced by Ser. These cells are not susceptible to redox-stress modification and activation. We postulate that the immune stimulatory effect of allicin is mediated by redox-sensitive signaling such as activation of p21(ras). It is suggested that the antitumor effect of allicin is related to its immune-stimulatory properties. 相似文献
50.
Hao Wang Ingeborg Barisic Maria Loane Marie‐Claude Addor Linda M. Bailey Miriam Gatt Kari Klungsoyr Olatz Mokoroa Vera Nelen Amanda J. Neville Mary O'Mahony Anna Pierini Anke Rissmann Christine Verellen‐Dumoulin Hermien E.K. de Walle Awi Wiesel Katarzyna Wisniewska Lolkje T.W. de Jong‐van den Berg Helen Dolk Babak Khoshnood Ester Garne 《American journal of medical genetics. Part A》2019,179(4):595-601
We aimed to assess prevalence, birth outcome, associated anomalies and prenatal diagnosis of congenital clubfoot in Europe using data from the EUROCAT network, and to validate the recording of congenital clubfoot as a major congenital anomaly by EUROCAT registries. Cases of congenital clubfoot were included from 18 EUROCAT registries covering more than 4.8 million births in 1995–2011. Cases without chromosomal anomalies born during 2005–2009, were randomly selected for validation using a questionnaire on diagnostic details and treatment. There was 5,458 congenital clubfoot cases of which 5,056 (93%) were liveborn infants. Total prevalence of congenital clubfoot was 1.13 per 1,000 births (95% CI 1.10–1.16). Prevalence of congenital clubfoot without chromosomal anomaly was 1.08 per 1,000 births (95% CI 1.05–1.11) and prevalence of isolated congenital clubfoot was 0.92 per 1,000 births (95% CI 0.90–0.95), both with decreasing trends over time and large variations in prevalence by registry. The majority of cases were isolated congenital clubfoot (82%) and 11% had associated major congenital anomalies. Prenatal detection rate of isolated congenital clubfoot was 22% and increased over time. Among 301 validated congenital clubfoot cases, diagnosis was confirmed for 286 (95%). In conclusion, this large population‐based study found a decreasing trend of congenital clubfoot in Europe after 1999–2002, an increasing prenatal detection rate, and a high standard of coding of congenital clubfoot in EUROCAT. 相似文献