首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   58878篇
  免费   5341篇
  国内免费   3405篇
耳鼻咽喉   890篇
儿科学   726篇
妇产科学   618篇
基础医学   7712篇
口腔科学   1152篇
临床医学   6914篇
内科学   9603篇
皮肤病学   844篇
神经病学   3371篇
特种医学   2922篇
外国民族医学   21篇
外科学   6339篇
综合类   7208篇
现状与发展   13篇
一般理论   5篇
预防医学   3519篇
眼科学   1336篇
药学   6106篇
  46篇
中国医学   2935篇
肿瘤学   5344篇
  2024年   195篇
  2023年   936篇
  2022年   2294篇
  2021年   3202篇
  2020年   2321篇
  2019年   2108篇
  2018年   2125篇
  2017年   1955篇
  2016年   1907篇
  2015年   2828篇
  2014年   3269篇
  2013年   3210篇
  2012年   4619篇
  2011年   4838篇
  2010年   3113篇
  2009年   2492篇
  2008年   3245篇
  2007年   3149篇
  2006年   2944篇
  2005年   2728篇
  2004年   1997篇
  2003年   1820篇
  2002年   1525篇
  2001年   1237篇
  2000年   1192篇
  1999年   1163篇
  1998年   636篇
  1997年   613篇
  1996年   485篇
  1995年   431篇
  1994年   390篇
  1993年   229篇
  1992年   373篇
  1991年   285篇
  1990年   278篇
  1989年   254篇
  1988年   224篇
  1987年   195篇
  1986年   164篇
  1985年   125篇
  1984年   83篇
  1983年   71篇
  1982年   28篇
  1981年   37篇
  1980年   24篇
  1979年   37篇
  1978年   25篇
  1977年   25篇
  1976年   35篇
  1974年   26篇
排序方式: 共有10000条查询结果,搜索用时 59 毫秒
101.
Technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) uptake is known to be increased in breast cancer because of increased blood flow from angiogenesis and heightened metabolism. We performed a 99mTc-MIBI scan in a patient with mammary Paget's disease. The patient had underlying invasive cancer in the same side of the breast. 99mTc-MIBI scan exhibited a scintigraphic image of the uptake from the invasive cancer lesion located deeply in the breast toward the epidermis. 99mTc-MIBI showed an uptake in the deeply located invasive cancer lesion as well as nipple lesion. Especially, the delayed phase of Tc-MIBI scan demonstrated the tumor site more accurately. In conclusion, 99mTc-MIBI scan could be a useful adjunct to clinical decision making in the management of Paget's disease of the breast.  相似文献   
102.
The case of a 54-year-old woman with metastatic follicular thyroid cancer and undetectable serum thyroglobulin is presented. Many years after the patient had a subtotal thyroidectomy for a large goiter that had no clear evidence of malignancy, metastatic bone disease developed. When the bone metastases were detected and during the follow-up period, serum thyroglobulin values remained undetectable, but radioiodine uptake in the metastases was abundant. This case indicates that the combination of 1-131 scintigraphy and serum thyroglobulin values is superior to the measurement of serum thyroglobulin alone in detecting well-differentiated, metastatic thyroid cancer.  相似文献   
103.
104.
The preventive effects of green tea, tea pigments, and mixed tea (a composite of whole water extract of green tea, tea polyphenols, and tea pigments) on 7,12-dimethyl-benz[a]anthracene (DMBA)-induced oral carcinogenesis in golden Syrian hamsters were studied. The right buccal pouches of animals were topically treated with 0.5% DMBA three times per week for 15 weeks. Animals were killed separately after 6, 10, and 15 weeks of DMBA treatment. Oral tumors were counted and measured, and mean tumor burden was calculated. The incidence of preneoplastic lesions and micronucleated cells, the number and volume of silver-stained nucleolar organizer regions (AgNOR), the labeling index of proliferating cell nuclear antigen, and the level of epidermal growth factor receptor expression were studied. The results showed that oral administration of 1.5% green tea, 0.1% tea pigments, and 0.5% mixed tea as the sole source of drinking water for two weeks before initiation of the DMBA treatment and until the end of the experiment significantly reduced the mean tumor burden and the incidence of dysplasia and oral carcinoma (p < 0.01). The frequency of micronucleated cells, the number of AgNOR, the total volume of AgNORs, the labeling index of proliferating cell nuclear antigen, and the level of epidermal growth factor receptor expression in the oral mucosal cells were also significantly reduced (p < 0.01). These results clearly indicated that tea preparations could effectively inhibit DMBA-induced oral carcinogenesis in hamsters. Protection from DNA damage and suppression of cell proliferation could be important mechanisms of the anticarcinogenic effects of the tea preparations.  相似文献   
105.
AIMS: To evaluate the effect of trans scleral cyclophotocoagulation (TSCPC) on intraocular pressure (IOP) in the eyes retaining intravitreal silicone oil with medically uncontrolled secondary glaucoma following intravitreal silicone oil injection. METHODS: Medical records of 11 eyes of 11 patients who underwent TSCPC for medically uncontrolled glaucoma without pupillary block following intravitreal silicone oil injection for complicated retinal detachment were reviewed retrospectively. In all cases, intravitreal silicone oil was not removed for fear of retinal redetachment. Diode laser contact TSCPC was performed at a power of 1.5-2.5 W, for a duration of 2 seconds, and with 20-27 applications. IOP, number of glaucoma medications, and success rate were evaluated. RESULTS: After a mean follow up period of 52.5 (SD 8.2) (range 42-68) weeks, the mean pretreatment level of IOP, 43.0 (14.4) (26-67) mmHg, had fallen to 14.5 (4.3) (7-20) mm Hg (p=0.003). The number of glaucoma medications was reduced from 2.6 (0.8) to 0.6 (1.0) (p= 0.005). Qualified success was achieved in nine eyes (81.8%) and complete success in six (54.5%). After TSCPC, patients' retinal status had not changed. CONCLUSION: Patients with medically uncontrolled glaucoma secondary to intravitreal silicone oil injection can be treated with TSCPC in spite of the retained intravitreal silicone oil.  相似文献   
106.
PURPOSE: To present clinical and histologic findings of intraocular infection with Mycobacterium bovis-bacille Calmette-Guérin after intravesicular bacille Calmette-Guérin injections for treatment of bladder carcinoma. METHODS: A 77-year-old man was initially seen with visual acuity of 20/200, focal retinitis, vasculitis, and progressive vitreous opacity in the right eye and visual acuity of light perception, intraocular inflammation, and a dense cataract in the left eye 14 months after intravesicular injection of live bacille Calmette-Guérin organisms. RESULTS: Vitreous cultures in the right eye demonstrated growth of bacille Calmette-Guérin organisms. Bilateral loss of light perception occurred despite systemic antimy-cobacterial therapy. Histopathologic examination demonstrated nongranulomatous inflammation and acid-fast bacilli in both eyes. CONCLUSION: Delayed endogenous endophthalmitis may develop after intravesicular bacille Calmette-Guérin injection that may not respond to systemic agents. Intravitreal therapy may be indicated.  相似文献   
107.
When liriodendrin or syringin was incubated for 24 h with human intestinal bacteria, two metabolites, (+)-syringaresinol-beta-D-glucopyranoside and (+)-syringaresinol, from liriodendrin and one metabolite, synapyl alcohol, from syringin were produced. The metabolic time course of liriodendrin was as follows: at early time, liriodendrin was converted to (+)-syringaresinol-beta-D-glucopyranoside, and then (+)-syringaresinol. The in vitro cytotoxicities of these metabolites, (+)-syringaresinol and synapyl alcohol, were superior to those of liriodendrin and syringin.  相似文献   
108.
In bioassay-guided search for inducible nitric oxide synthase (iNOS) inhibitory compounds from higher plants of South Korea, two beta-carboline alkaloids, 4-methoxy-1-vinyl-beta-carboline (1) and 4,8-dimethoxy-l-vinyl-beta-carboline (2) have been isolated from the cortex of Melia azedarach var. japonica. The structures of these compounds were elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed marked inhibitory activity of iNOS on LPS- and interferon-gamma-stimulated RAW 264.7 cells.  相似文献   
109.
Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells.  相似文献   
110.
Socialization games, designed to reinforce prosocial behavior between moderately and severely mentally retarded aggressive institutionalized women, were presented to two groups on 12 occasions over 8 weeks, randomly interspersed with 12 sessions of arts and crafts or filmstrip stories. Half of the sessions were presented in the morning and half in the afternoon. Video-taped observations of interpersonal behavior for 10 minutes after each session were analyzed in terms of friendly, unfriendly, and inactive behavior, and the distance of each subject from each other subject was measured. The rate of friendly behavior was significantly greater after the games and was higher in morning than afternoon sessions. The games also significantly decreased interpersonal distance. Both unfriendly behavior and inactivity were higher after the "placebo" sessions. The relevance of these results to institutional programming was discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号