全文获取类型
收费全文 | 270436篇 |
免费 | 23982篇 |
国内免费 | 7552篇 |
专业分类
耳鼻咽喉 | 2209篇 |
儿科学 | 9865篇 |
妇产科学 | 5467篇 |
基础医学 | 45296篇 |
口腔科学 | 4818篇 |
临床医学 | 23615篇 |
内科学 | 43618篇 |
皮肤病学 | 5277篇 |
神经病学 | 23371篇 |
特种医学 | 8015篇 |
外国民族医学 | 36篇 |
外科学 | 23162篇 |
综合类 | 32796篇 |
现状与发展 | 40篇 |
预防医学 | 13911篇 |
眼科学 | 3692篇 |
药学 | 25801篇 |
110篇 | |
中国医学 | 16318篇 |
肿瘤学 | 14553篇 |
出版年
2024年 | 758篇 |
2023年 | 4657篇 |
2022年 | 9817篇 |
2021年 | 12395篇 |
2020年 | 10938篇 |
2019年 | 10337篇 |
2018年 | 10160篇 |
2017年 | 10109篇 |
2016年 | 9925篇 |
2015年 | 10367篇 |
2014年 | 17395篇 |
2013年 | 18221篇 |
2012年 | 14953篇 |
2011年 | 17564篇 |
2010年 | 13864篇 |
2009年 | 13562篇 |
2008年 | 13370篇 |
2007年 | 12567篇 |
2006年 | 11085篇 |
2005年 | 9645篇 |
2004年 | 8302篇 |
2003年 | 7365篇 |
2002年 | 5416篇 |
2001年 | 4830篇 |
2000年 | 4075篇 |
1999年 | 3786篇 |
1998年 | 3493篇 |
1997年 | 3276篇 |
1996年 | 3023篇 |
1995年 | 2880篇 |
1994年 | 2601篇 |
1993年 | 2360篇 |
1992年 | 1889篇 |
1991年 | 1567篇 |
1990年 | 1432篇 |
1989年 | 1199篇 |
1988年 | 1110篇 |
1987年 | 1028篇 |
1986年 | 1065篇 |
1985年 | 1516篇 |
1984年 | 1460篇 |
1983年 | 1023篇 |
1982年 | 1157篇 |
1981年 | 963篇 |
1980年 | 824篇 |
1979年 | 707篇 |
1978年 | 449篇 |
1977年 | 371篇 |
1976年 | 373篇 |
1975年 | 220篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
81.
Intestinal intraepithelial lymphocytes (iIEL) are primarily CD8 cells and most of them have a CD28? phenotype, the phenotype of effector cytotoxic T cells. We asked whether the predominance of CD8+ CD28? T cells in the gut may result from peripheral blood T cells preferentially migrating to the iIEL compartment and adhering to iEC. Compared with CD4 cells, adhesion of resting CD8+ T cells to iEC cell lines was significantly higher. Adhesion could be blocked with a MoAb to gp180, a molecule expressed on iEC which is known to interact with CD8/lck. No significant difference in the level of adhesion was observed between CD8+ CD28+ and CD8+ CD28? T cells. Thus CD8 cells may preferentially migrate to the iIEL compartment, but loss of CD28 expression could occur in situ after migration. Consistent with this hypothesis, the CD8+ CD28? cells became enriched after co-culturing T cells with iEC cell lines and primary iEC. Induction of the CD8+ CD28? phenotype in cord blood and adult T cells was observed in co-cultures with iEC and also with mitogens and superantigens. In the latter case, CD28 down-modulation was seen specifically in the Vβ subset targeted by the superantigen, indicating that loss of CD28 expression is a direct result of T cell receptor (TCR)-mediated stimulation. The combined results suggest that CD8+ CD28? T cells are antigen experienced T cells, and that they may have a survival advantage in the presence of gut epithelial cells in vitro. This may contribute to the predominance of CD8+ CD28? T cells in the iIEL compartment. 相似文献
82.
A case of the neuroleptic malignant syndrome occurred in a 40-year-old male after administration of chlorpromazine while on an Intensive Therapy Unit. Treatment with dantrolene sodium was successful, and a muscle biopsy was examined in the recovery phase of the illness. The importance of this condition and the difficulties in establishing a diagnosis at an early stage in patients on an Intensive Therapy Unit are discussed, along with implications for treatment. 相似文献
83.
MASAAKI KATO MD NAOFUMI KAJIMURA MD MASANORI SEKIMOTO MD TSUYOSHI WATANABE MD KIYOHISA TAKAHASHI MD 《Psychiatry and clinical neurosciences》1998,52(2):262-263
Abstract We tried melatonin treatment in two patients with non-24 h sleep-wake syndrome, who did not respond to treatments by vitamin B12 , bright light therapy, or hypnotics. In one patient, melatonin 5–10 mg improved difficulty in falling asleep and in waking, although it failed to improve the sleep-wake rhythm. In another patient, melatonin 3 mg successfully changed the sleep-wake rhythm from free-running pattern to delayed sleep phase pattern. However, melatonin re-administration after a 4-month drug-free interval failed to improve his free-running sleep-wake rhythm. These results suggest that melatonin acted as a sleep inducer in one patient and as a phase setter in the other, although the effect on the latter patient was transient. 相似文献
84.
Hisashi Tanii Norio Taniguchi Hisayoshi Niigawa Takayoshi Hosono Yasumitsu Ikura Sakae Sakamoto Takashi Kudo Tsuyoshi Nishimura Masatoshi Takeda 《Brain research》1996,743(1-2)
The neuroleptic malignant syndrome (NMS) is a life-threatening complication of neuroleptic treatment. To elucidate the pathogenesis of NMS, an animal model has been developed. Experimental rabbits treated with haloperidol (1 mg/kg) by intramuscular injection, were studied for the diagnostic symptoms of increased muscle rigidity, elevated body temperature, and high serum creatine phosphokinase (CPK) level. Administration of haloperidol (1 mg/kg) and atropine (0.4 mg/kg), and exposure to high ambient temperature (35°C) induced a significant increase in electromyographic activity with muscle rigidity similar to that observed in patients with NMS. Such rabbits also showed elevated body temperature and serum CPK value. In addition to the similarity of the signs and symptoms, all parameters measured (muscle rigidity, body temperature, and serum CPK level) were normalized by dantrolene treatment. The effectiveness of dantrolene in the experimental animal partially confirms the validity of this animal model for NMS. This experimental animal model for NMS may be useful to elucidate the pathogenesis of NMS. 相似文献
85.
J. B. Payne R. A. Reinhardt M. P. Masada L. M. DuBois A. C. Allison 《Journal of periodontal research》1993,28(6):451-453
Gingival crevicular fluid (GCF) IL-8 and IL-1,1β levels were determined by sandwich enzyme-linked immunosorbent assays. Associations between IL-8 and IL-1β GCF levels, and between these cytokines and patient estrogen status were evaluated. IL-8 and IL-1β were detected more frequently and in higher amounts/30 s GCF sample in estrogen-deficient patients than in estrogensufficient patients. IL-8 and IL-1β GCF levels were significantly correlated. These lindings suggest that GCF IL-8 levels are associated with patient estrogen status and local IL-1β concentrations. 相似文献
86.
M. Ohshima A. Yokoyama H. Ohnishi H. Hamada N. Kohno J. Higaki T. Naka 《Clinical and experimental allergy》2007,37(5):735-742
BACKGROUND: Enhanced expression of the suppressor of cytokine signalling (SOCS)-5 might be of therapeutic benefit for T-helper type 2 (Th2) dominant diseases, as its expression is reported to result in a reduction of Th2 differentiation in vitro due to the inhibition of IL-4 signalling. OBJECTIVE: To investigate the regulatory role of SOCS-5 in vivo, we explored the phenotype of an experimental asthma model developed in SOCS-5 transgenic (Tg) mice. METHODS: The SOCS-5 Tg mice or wild-type (WT) mice were sensitized and repeatedly challenged with ovalbumin (OVA). We examined bronchoalveolar lavage fluid (BALF), lung specimens, and airway hyperresponsiveness (AHR) to methacholine. RESULTS: The production of IFN-gamma by CD4(+) T cells from unprimed SOCS-5 Tg mice was significantly increased in comparison with unprimed wild-type mice, indicating that SOCS-5 Tg mice have a Th1-polarizing condition under natural conditions. However, in an asthma model, significantly more eosinophils in the airways and higher levels of IL-5 and IL-13 in BALF were observed in the SOCS-5 Tg than the wild-type mice. AHR in the asthma model of SOCS-5 Tg was also more enhanced than that of wild-type mice. OVA-stimulated CD4(+) T cells from the primed SOCS-5 Tg mice produced significantly more IL-5 and IL-13 than CD4(+) T cells from wild-type mice. CONCLUSION: Our results demonstrate that the overexpression of SOCS-5 does not inhibit Th2 response, but rather augments the phenotype of the asthma model in vivo. This finding throws into question the therapeutic utility of using enhancement of SOCS-5 expression for Th2-dominant disease. 相似文献
87.
目的 :研究SideropenicDysphagla (S -D)综合征膜性蹼产生的机制。方法 :回顾分析S -D综合征2 6例的临床资料。结果 :影像学检查显示膜性蹼在颈段食道前壁呈 2mm深的模样陷凹。血液学检查为缺铁性低血红蛋白性贫血改变。结论 :缺铁性贫血是S -D综合征的原因 ,铁剂治疗有效 相似文献
88.
The effect of the barbiturate T2000 (1,3-dimethoxymethyl-5,5-diphenyl-barbituric acid; DMMDPB) on essential tremor, given in twice daily doses of 400 and 300 mg, was assessed in two brief, randomized, placebo-controlled, parallel-group, double-blinded, single-center trials in 12 and 22 patients, respectively. These trials represent the first clinical use of T2000 for a specific indication. The primary endpoint was the change in the mean scores of the treated and control groups based on the Fahn-Tolosa-Marin tremor scale. In the first study of 12 patients treated with 400 mg or placebo twice daily for 14 days, the mean change from baseline at day 14 was 19.3 (P < 0.0001) in the treated group and 9.0 (P = 0.0121) in the control group. Using a two-factor mixed ANOVA model to evaluate within group and between group changes, the effect of T2000 was significantly different from that of the placebo group (P = 0.03). In the second study of 22 patients treated with 300 mg of T2000 or placebo twice daily for 20 days, statistically significant changes were seen in treated patients compared to baseline, but the ANOVA model did not demonstrate a significant treatment effect of T2000 compared to placebo. When the treated groups from each study are compared, the 800-mg daily group is significantly different from the 600-mg daily group (P = 0.02). Some treated patients in each study, but no placebo patients, experienced marked improvement. These results support further evaluation of T2000 in the treatment of essential tremor. 相似文献
89.
G Weiss†‡ Y Confino† A Shemer†‡ H Trau†‡ 《Journal of the European Academy of Dermatology and Venereology》2004,18(3):324-327
We report one patient with cardiofaciocutaneous (CFC) syndrome. He presented with clinical findings characteristic of this condition such as: cutaneous abnormalities, including ichthyosis, widespread keratosis pilaris, a peculiar craniofacial appearance with sparse, curly hair and low-set posteriorly rotated ears; congenital heart defects; and mild mental and motor retardation. We submit a comprehensive review of previously published articles regarding the dermatological findings in CFC syndrome (recently shown to be a variant of Noonan syndrome) emphasizing diagnostic criteria and its differentiation from the Costello syndrome. 相似文献
90.
MC Brouard P Chavaz L Borradori 《Journal of the European Academy of Dermatology and Venereology》2004,18(1):89-92
BACKGROUND: Bowel-associated dermatosis-arthritis syndrome denotes the occurrence of diarrhoea with arthritis and skin lesions related to bowel disease with or without bowel bypass. In this condition, the histological finding of cutaneous aseptic neutrophilic cell infiltrate is non-specific and common to a wide spectrum of neutrophilic dermatoses, including pyoderma gangrenosum. OBSERVATION: We describe a 78-year-old woman with fever, abdominal discomfort and arthralgias, who developed grouped pustular lesions on her shins with histologically spongiform pustule formation. Aetiological assessment disclosed diverticular disease with sigmoid stenosis. CONCLUSION: Although clinical and histological features in our case fit the diagnosis of bowel-associated dermatosis-arthritis syndrome, they may also correspond to a pustular variant of pyoderma gangrenosum. Our observation raises the question of the nosological classification of bowel-associated dermatosis-arthritis syndrome within the spectrum of neutrophilic diseases. 相似文献