全文获取类型
收费全文 | 25079篇 |
免费 | 2238篇 |
国内免费 | 552篇 |
专业分类
耳鼻咽喉 | 932篇 |
儿科学 | 444篇 |
妇产科学 | 504篇 |
基础医学 | 4150篇 |
口腔科学 | 1374篇 |
临床医学 | 2425篇 |
内科学 | 2125篇 |
皮肤病学 | 331篇 |
神经病学 | 867篇 |
特种医学 | 1048篇 |
外国民族医学 | 20篇 |
外科学 | 3013篇 |
综合类 | 3941篇 |
现状与发展 | 1篇 |
预防医学 | 892篇 |
眼科学 | 892篇 |
药学 | 1514篇 |
25篇 | |
中国医学 | 528篇 |
肿瘤学 | 2843篇 |
出版年
2024年 | 87篇 |
2023年 | 411篇 |
2022年 | 799篇 |
2021年 | 1003篇 |
2020年 | 993篇 |
2019年 | 899篇 |
2018年 | 817篇 |
2017年 | 864篇 |
2016年 | 971篇 |
2015年 | 972篇 |
2014年 | 1535篇 |
2013年 | 1475篇 |
2012年 | 1348篇 |
2011年 | 1411篇 |
2010年 | 1255篇 |
2009年 | 1066篇 |
2008年 | 1099篇 |
2007年 | 1069篇 |
2006年 | 1003篇 |
2005年 | 894篇 |
2004年 | 789篇 |
2003年 | 698篇 |
2002年 | 571篇 |
2001年 | 562篇 |
2000年 | 481篇 |
1999年 | 441篇 |
1998年 | 406篇 |
1997年 | 381篇 |
1996年 | 359篇 |
1995年 | 322篇 |
1994年 | 279篇 |
1993年 | 278篇 |
1992年 | 233篇 |
1991年 | 227篇 |
1990年 | 203篇 |
1989年 | 196篇 |
1988年 | 162篇 |
1987年 | 133篇 |
1986年 | 151篇 |
1985年 | 153篇 |
1984年 | 147篇 |
1983年 | 73篇 |
1982年 | 114篇 |
1981年 | 120篇 |
1980年 | 105篇 |
1979年 | 61篇 |
1978年 | 63篇 |
1977年 | 57篇 |
1976年 | 35篇 |
1975年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Mehrotra P Okpokam A Bouhaidar R Johnson SJ Wilson JA Davies BR Lennard TW 《Histopathology》2004,45(5):493-500
AIMS: To determine whether galectin-3 is a sensitive indicator of thyroid malignancy. It has been suggested as a potential marker for differentiating thyroid carcinoma from benign or non-neoplastic lesions in preoperative fine-needle aspirates (FNAs). METHODS: Galectin-3 protein expression was assessed by immunohistochemistry in formalin-fixed thyroid tissues from 124 patients with histological diagnoses of papillary carcinoma (n = 38), follicular carcinoma (n = 19), follicular adenoma (n = 32) and dominant nodules of multinodular goitre (n = 35). Expression of galectin-3 was also assessed by Western blotting in 24 fresh thyroid tissues. RESULTS: Galectin-3 expression was observed in the majority of carcinomas (papillary 92%; follicular 74%). However, a large proportion of follicular adenomas (72%) and multinodular goitres (57%) also expressed galectin-3. In addition, galectin-3 expression was observed in epithelial cells of normal thyroid tissue and Hashimoto's thyroiditis. Galectin-3 immunopositivity was significantly greater in papillary carcinomas than in dominant nodules or follicular adenomas (P < 0.0001, P = 0.0005, respectively). However, galectin-3 expression was no greater in follicular carcinomas than in follicular adenomas (P = 0.8735). Western blotting analysis confirmed both the specificity of the antiserum and expression of galectin-3 in multinodular goitres, follicular adenomas/carcinomas and papillary carcinomas. CONCLUSION: The data demonstrate that galectin-3 is not a reliable immunohistochemical marker to distinguish benign from malignant thyroid follicular lesions. 相似文献
92.
目的:探讨保留甲状软骨膜对全喉切除手术进程和病人术后恢复情况的影响。方法:在甲状软骨膜下游离甲状软骨并切断其上角。不结扎和切断舌骨下肌群和喉上动脉。保留之甲状软骨膜用以加强修复咽壁黏膜。结果:本组病例较经典全喉切除术手术时间缩短30min以上。手术中出血在100ml以下。患者术后第2d下床活动,第4d开始进食流质。手术创口均一期愈合。结论:全喉切除术中保留甲状软骨膜可有效地简化手术步骤,减少创伤和出血。利用甲状软骨膜加强咽壁黏膜缝合口,进一步减少了咽漏的发生. 相似文献
93.
Negro R Mangieri T Coppola L Presicce G Casavola EC Gismondi R Locorotondo G Caroli P Pezzarossa A Dazzi D Hassan H 《Human reproduction (Oxford, England)》2005,20(6):1529-1533
BACKGROUND: Infertile women positive for thyroid antibodies suffer from a poor pregnancy/delivery outcome, although conflicting data have been published. Our objective was to investigate if levothyroxine (LT4) exerts any effect on pregnancy and/or delivery rates in thyroid peroxidase antibody (TPOAb)-positive (+) women undergoing assisted reproductive technologies. METHODS: Patients undergoing treatment were screened for TPOAb, thyroid-stimulating hormone (TSH) and free thyroxine (FT4). A total of 72 (15%) out of the 484 euthyroid women selected were TPOAb (+). These 72 patients were randomly divided into two groups: group A (n = 36) underwent LT4 treatment, group B (n = 36) placebo. Group C consisted of 412 women (85%) who were TPOAb negative (-). All patients received controlled ovarian stimulation. The endpoints of treatment were pregnancy rate, miscarriage rate and delivery rate. RESULTS: No differences in pregnancy rate were observed between the three groups. Miscarriage rate was higher in TPOAb (+) in comparison to TPOAb (-) [relative risk: 2.01 (95% CI = 1.13-3.56), P = 0.028]. CONCLUSIONS: The pregnancy rate is not affected either by presence of TPOAb or treatment with LT4. However, TPOAb (+) women show a poorer delivery rate compared to TPOAb (-). LT4 treatment in TPOAb (+) does not affect the delivery rate. 相似文献
94.
Cappelli C Tironi A Mattanza C Cumetti D Agosti B Gandossi E Pirola I De Martino E Cherubini L Micheletti L Castellano M Rosei EA 《Endocrine pathology》2005,16(4):349-354
Objective: To compare the cytological findings of hypoechoic thyroid nodules with intranodular vascular pattern (pattern II) obtained
by two different needles (Neolus 25 gauge, Chemil, Wenzhou, China vs Yale Spinal 25 gauge, Becton Dickinson, Madrid, Spain)
in euthyroid patients and to evaluate their cost-effectiveness.
Methods: From January 2001 to December 2003, 480 euthyroid patients with a hypoechoic thyroid nodule pattern II were referred for
US-FNAC. The nodules were alternatively evaluated by Neolus or by Yale Spinal with the stylet (YS+) or without the stylet
(YS−), in order to evaluate if the cytological results could be due to the presence of the stylet or to the different length
of the two needles. For each nodule two passes were performed and the material was obtained by capillary action. Material
was smeared on slides, fixed, and stained by Papanicolaou techniques. Cytological specimens were evaluated in blind by the
same experienced cytopathologist.
Results: Inadequate cytological specimens because of blood contamination were present in 30 (18.7%) samples by Neolus needle and in
22 (13.8%) by YS− compared to only 5 (3.1%) by YS+. In 6 (20%) cases of the 30 repeated US-FNAC by Neolus and in 4 (18%) of
the 22 US-FNAC by YS−, material remained inadequate for diagnosis because of blood contamination. All the five repeated samples
obtained by YS+ became adequate for diagnosis and resulted benign nodules. Direct costs of US-FNAC procedure are currently
Э 72.30 including cytological examination. The cost of Neolus and Yale needles is Э 0.19 and Э 3.0, respectively. The estimated
total cost to obtain a cytological diagnosis by a Neolus needle (160 + 30 repeated US-FNAC) was Э 13809.2 vs Э 12919.5 by
Yale Spinal needle (160 + 5 repeated US-FNAC).
Conclusion: This study demonstrates that the use of Yale Spinal needles greatly reduces inadequate cytological specimens, and therefore
limits both direct and indirect costs. 相似文献
95.
汗腺癌病理分级的预后意义 总被引:3,自引:0,他引:3
目的:探讨汗腺癌不同病理组织学分级对复发和转移及预后的影响。方法:参照Bloom-Richardson乳腺癌分级标准对105例汗腺癌进行分级,并探讨其与复发、转移和预后间的关系。结果:在105例汗腺癌中,属分化型者42例,属低分化型者63例,两者复发率、多次复发率、区域淋巴结转移率和远处转移率及死亡率比较,提示在多次复发、远处转移方面差异有显著性,在预后方面差异非常显著。结论:将汗腺癌按腺管形成多少、核的多形性和核分裂数进行病理组织学分级,对选择治疗、估计预后具有很大的指导意义 相似文献
96.
N. Tsuchikame Y. Ishimaru S. Ohshima M. Takahashi 《Virchows Archiv : an international journal of pathology》1993,422(4):337-340
We report three cases of fundic gland polyposis in the stomach identified in three patients who were related. Grossly the numerous polyps covered an area limited to the body and fundus of the stomach, no polyps were found in the antrum, duodenum, colon, or rectum, and histologically, the gastric lesions consisted of numerous hamartomatous polyps, characterized by proliferation of the fundic and cystic glands. The gastric lesions were identified in families without polyposis coli. This type of fundic gland polyposis has never been documented before in the literature. 相似文献
97.
98.
Louise A. Rollins-Smith Patrick J. Blair A. Tray Davis 《Clinical & developmental immunology》1992,2(3):207-213
Metamorphosis in amphibians presents a unique problem for the developing immune
system. Because tadpoles are free-living, they need an immune system to protect against
potential pathogens. However, at metamorphosis, they acquire a variety of new adultspecific
molecules to which the tadpole immune system must become tolerant. We
hypothesized that Xenopus laevis tadpoles may avoid potentially destructive antiself
responses by largely discarding the larval immune system at metamorphosis and
acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we
examined the influx and expansion of host T-cell precursors in the donor thymus of
normally metamorphosing and metamorphosis-inhibited frogs. We observed that donor
thymocytes are replaced by host-derived cells during metamorphosis, but inhibition of
metamorphosis does not prevent this exchange of cells. The implanted thymuses export
T cells to the spleen. This donor-derived pool of cells declines after metamorphosis in
normally developing frogs but is retained to a greater extent if metamorphosis is
inhibited. These studies confirm previous observations of a metamorphosis-associated
wave of expansion of T cells and demonstrate that it is not dependent on the relatively
high concentrations of thyroid hormones required for metamorphosis. Although some
larval T cells persist through metamorphosis, others may be destroyed or the larval
population is significantly diluted by the expanding adult population. 相似文献
99.
Anti-human thyroid peroxidase and anti-human thyroglobulin antibodies present no cross-reactivity on recombinant peptides. 下载免费PDF全文
Thyroglobulin (Tg) and thyroid peroxidase (TPO) are two antigens largely recognized by the sera from patients with autoimmune thyroid disease (AITD). Recently, the complete mapping of both antigens was established with rabbit polyclonal antibodies by the use of recombinant proteins expressed in prokaryotic vector. Several investigators have argued for the existence of a cross-reactivity of some hetero- and autologous antibodies versus these two proteins. In the present study, using rabbit polyclonal antibody, mouse polyclonal antibody and autoimmune antibody (aAb), we observed no common epitope on human Tg (hTg) and human TPO (hTPO). 相似文献
100.
Heinz Gögelein Eberhard Schlatter Rainer Greger 《Pflügers Archiv : European journal of physiology》1987,409(1-2):122-125
Besides the larger Cl– channel with a single channel conductance of about 45 pS, a small channel was observed in the luminal membrane of the dogfish rectal gland [9]. In cell excised (inside out) patches with NaCl solution on both sides, the latter channel had a single channel conductance of 11±1 pS (n=21), and its current-voltage relationship was linear in the voltage range+90 to –90 mV. The open state probability increased moderately with negative clamp potentials. Ionic replacement studies revealed a high selectivity of Cl– over gluconate, sulfate, and iodide, whereas bromide was permeable to some extent. Also the channel is impermeable for Na+. The Cl– channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoate did not affect this small conductance Cl– channel. It can be concluded that the luminal membrane of stimulated rectal gland cells possesses two types of Cl– channels, which differ markedly in their characteristics.Supported by Deutsche Forschungsgemeinschaft Gr 480/8 and by NSF and NIH grants to the MDIBL 相似文献