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   63745篇
  免费   4877篇
  国内免费   1751篇
耳鼻咽喉   838篇
儿科学   1187篇
妇产科学   2219篇
基础医学   8050篇
口腔科学   1160篇
临床医学   6833篇
内科学   11951篇
皮肤病学   1193篇
神经病学   3960篇
特种医学   2614篇
外国民族医学   6篇
外科学   8532篇
综合类   4199篇
现状与发展   7篇
一般理论   11篇
预防医学   3502篇
眼科学   1400篇
药学   5330篇
  20篇
中国医学   1678篇
肿瘤学   5683篇
  2023年   523篇
  2022年   1321篇
  2021年   2149篇
  2020年   1308篇
  2019年   1621篇
  2018年   2005篇
  2017年   1520篇
  2016年   1567篇
  2015年   2334篇
  2014年   2916篇
  2013年   3396篇
  2012年   4816篇
  2011年   4691篇
  2010年   2986篇
  2009年   2613篇
  2008年   3539篇
  2007年   3539篇
  2006年   3384篇
  2005年   3124篇
  2004年   2828篇
  2003年   2710篇
  2002年   2352篇
  2001年   1843篇
  2000年   1609篇
  1999年   1336篇
  1998年   553篇
  1997年   458篇
  1996年   416篇
  1995年   377篇
  1994年   348篇
  1993年   242篇
  1992年   711篇
  1991年   582篇
  1990年   531篇
  1989年   484篇
  1988年   421篇
  1987年   424篇
  1986年   355篇
  1985年   295篇
  1984年   229篇
  1983年   191篇
  1982年   114篇
  1981年   122篇
  1980年   99篇
  1979年   205篇
  1978年   161篇
  1977年   103篇
  1976年   110篇
  1975年   102篇
  1974年   99篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
目的比较DVd方案与VAdM方案治疗初治多发性骨髓瘤(MM)的临床效果及患者不良反应。方法17例初治MM患者接受DVd方案:盐酸多柔比星脂质体40mg·m^-2·d^-1,第1天;长春新碱2.0mg/d,第1天;静脉地塞米松20mg/d,第1天至第4天,每28d一个疗程。同期住院16例接受VAdM的初治MM患者作为对照:静脉注射吡柔比星9mg·m^-2·d^-1,第1天;长春新碱0.5mg/d,第1天至第4天;静脉地塞米松20mg/d,第1天至第4天;美法仑12mg/d,第1天至第4天;每28d一个疗程。结果DVd组和VAdM组的总反应率相似(76.5%比81.3%,P=0.737)。但在达到平均最大反应时间DVd组优于VAdM组[(3.2±1.7)个月比(4.6±1.0)个月,P=0.039]。DVd组Ⅲ级以上粒细胞减少的发生率(23.5%比68.8%,P=0.015)、因粒细胞缺乏或严重感染需要G—CSF注射比例(11.8%比62.5%,P=0.00.4),抗生素的使用(11.8%比37.5%,P=0.118)以及因不良反应而需要延长住院时间方面(37.5%比17.6%,P:0.259)均小于VAdM组。DVd组手足综合征的发生率明显高于VAdM组。结论DVd方案与传统VAd方案疗效类似,毒副作用小,相应支持治疗也较少,可以作为VAd的一个有效替代方案,用于MM的一线治疗。  相似文献   
942.
Female sexual function and pelvic floor disorders   总被引:2,自引:0,他引:2  
OBJECTIVE: To investigate the hypothesis that pelvic floor disorders are associated with female sexual problems, independently of other related factors. METHODS: The study population included 301 adult women seeking outpatient gynecologic and urogynecologic care. Pelvic floor disorders were assessed with the Pelvic Floor Disorders Inventory-20 (PFDI-20) and the pelvic organ prolapse quantification examination. Sexual function was assessed with the Personal Experiences Questionnaire. Using ordinal regression analysis, we identified characteristics and conditions associated with decreased libido, infrequent orgasm, decreased arousal, and dyspareunia. RESULTS: Sexual function was poorer among 78 women (26%) without a current sexual partner than among 223 with a partner (P<.01). Among the 223 with a current partner, women with a high Pelvic Floor Disorders Inventory score were significantly more likely to report decreased arousal (P<.01), infrequent orgasm (P<.01), and increased dyspareunia (P<.01). A similar pattern was observed for the urinary, colorectal-anal, and prolapse scales of the Pelvic Floor Disorders Inventory, although some associations were marginally significant. Stage III-IV prolapse was significantly associated with infrequent orgasm (P=.02), but other sexual complaints were not more common with increasing prolapse stage. CONCLUSION: Pelvic floor symptoms are significantly associated with reduced sexual arousal, infrequent orgasm, and dyspareunia. We conclude that sexual function is worse in women with symptomatic prolapse but not in women with asymptomatic prolapse. LEVEL OF EVIDENCE: II.  相似文献   
943.
STUDY OBJECTIVE: To estimate whether laparoscopic in situ morcellation (LISM) can facilitate laparoscopic-assisted vaginal hysterectomy (LAVH) for large uteri. DESIGN: Prospective study (Canadian Task Force classification II-1). SETTING: University-affiliated hospital. PATIENTS: In all, 147 women with myoma or adenomyosis weighing more than 500 g from January 2004 through December 2007 were enrolled. The patients were divided into 4 subgroups: patients with uteri weighing 500 to 749 g who had traditional LAVH without LISM (group 1A, n = 69) or with LISM (group 1B, n = 16); and patients with uteri weighing 750 g or more who were treated by traditional LAVH without LISM (group 2A, n = 38) or with LISM (group 2B, n = 24). INTERVENTIONS: Laparoscopic-assisted vaginal hysterectomy with or without LISM. MEASUREMENT AND MAIN RESULTS: No significant differences existed in age, body mass index, preoperative diagnoses, complications, or duration of hospital stay among groups. The mean uterine weights were 608 +/- 75, 597 +/- 66, 989 +/- 179, and 935 +/- 226 g for groups 1A, 1B, 2A, and 2B, respectively. The operative time (120 +/- 16 vs 157 +/- 36 minutes, p <.001; 140 +/- 19 vs 224 +/- 57 minutes, p <.001) were significantly shorter in patients with LISM than without in both groups 1 and 2. The estimated blood loss was highest in group 2A. Six (16%) patients lost more than 500 mL of blood and 3 (8%) of them needed blood transfusions. Conversion to laparotomy occurred in 1 (2.6%) of 38 patients in group 2A. No repeated surgery or surgical mortality occurred. CONCLUSION: Laparoscopic-assisted vaginal hysterectomy with LISM was an efficient and safe procedure for removal of large uteri during LAVH.  相似文献   
944.
Persistent uterine prolapse with secondary acute renal failure is a very uncommon event. We report the case of a 77-year-old woman with a 5-year history of uterine prolapse. She was referred to our gynecologic oncology service for 3rd degree uterine prolapse and was found to have bilateral hydronephrosis and acute renal insufficiency. The patient was fitted for a pessary to manage the uterine prolapse, which resulted in resolution of her hydronephrosis and renal insufficiency. Prompt assessment with nephrology consultation and pessary placement for patients with 3rd degree genital prolapse is imperative to ensure that irreversible renal complications do not manifest themselves. This study was supported by a grant from the Women’s Cancer Research Foundation.  相似文献   
945.
946.
Six new phthalides, (S)-3-ethyl-7-hydroxy-6-methoxyphthalide (1), (S)-3-ethyl-7-hydroxy-5,6-dimethoxyphthalide (2), (S)-3-ethyl-5,6,7-trimethoxyphthalide (3), (R)-3-ethyl-7-hydroxy-6-methoxyphthalide (4), (Z)-3-ethylidene-7-hydroxy-6-methoxyphthalide (5), and (Z)-3-ethylidene-6,7-dimethoxyphthalide (6), have been isolated from the root of Pittosporum illicioides var. illicioides, together with seven known compounds. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1-4 exhibited inhibition (IC50相似文献   
947.
Four new cyclopeptides, cyclomontanins A-D (1- 4), annomuricatin C (5), and (+)-corytuberine were isolated from a methanol extract of Annona montana seeds. Their structures were elucidated by 2D NMR analysis, ESIMS/MS fragment evidence, and chemical means. The structure of 1 was confirmed by synthesis. Compounds 1, 3, and 4 exhibited anti-inflammatory activity in vitro using the J774.1 macrophage model.  相似文献   
948.
Four new cucurbitane-type triterpenes, cucurbita-5,23(E)-diene-3beta,7beta,25-triol (1), 3beta-acetoxy-7beta-methoxycucurbita-5,23(E)-dien-25-ol (2), cucurbita-5(10),6,23(E)-triene-3beta,25-diol (5), and cucurbita-5,24-diene-3,7,23-trione (6), together with four known triterpenes, 3beta,25-dihydroxy-7beta-methoxycucurbita-5,23(E)-diene (3), 3beta-hydroxy-7beta,25-dimethoxycucurbita-5,23(E)-diene (4), 3beta,7beta,25-trihydroxycucurbita-5,23(E)-dien-19-al (7), and 25-methoxy-3beta,7beta-dihydroxycucurbita-5,23(E)-dien-19-al (8), were isolated from the methyl alcohol extract of the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods.  相似文献   
949.
Baicalin is a flavonoid present in many traditional Chinese medicines. A number of studies show that baicalin has anti-inflammatory actions and protects against a variety of tissue and organ injuries. The effect of baicalin in lipopolysaccharide (LPS)-induced acute lung injury is not well studied. In this study, typically acute lung injury was induced in rat by intratracheal injection of LPS, which increased lactate dehydrogenase activity and protein content in bronchoalveolar lavage fluid, wet/dry lung weight ratio, Evan's blue dye leakage, and neutrophil infiltration. Baicalin (20 mg/kg) was administrated 1 hour before or 30 min after LPS injection. Both pre and post-treatment with baicalin attenuated the increase of these parameters and improved histological finding. Our results suggest that baicalin has a therapeutic effect on LPS-induced acute lung injury.  相似文献   
950.
AIM OF THE STUDY: Hypoglycaemic and hypolipidemic properties of the ethanolic and aqueous extracts, respectively, from Chinese juniper (Juniperus chinensis L.) berries were investigated in alloxan-induced diabetic rats. MATERIALS AND METHODS: After oral administration of each extract singly or repeatedly to alloxan-induced diabetic rats, the blood glucose, glutamate-pyruvate transferase (GPT), glutamate-oxaloacetate transaminase (GOT), total cholesterol (TC) and triglyceride (TG) levels were assayed. RESULTS: The blood glucose levels after a single oral administration of the ethanolic extract significantly reduced in a time-dependent manner, which is much faster and more than that of glibenclamide. The blood glucose levels of alloxan-induced diabetic rats treated with the ethanolic extract were reduced to 94, 81%, 66%, 45% and 40% at 1, 3, 5, 7 and 9h, respectively (p<0.05), while the aqueous extract had no effect at all. Repeated oral administration of the ethanolic extract also effectively reduced the GPT value to 58% of the diabetic rats, but slightly reduced the GOT value to 87% of the diabetic rats (p<0.05). On the other hand, the repeated oral administration of aqueous extract effectively reduced the GOT value to 43% of the diabetic rats, without affecting the GPT level. Effects of both extracts on the TC and TG levels were different. There was no significant difference in the TC and TG levels between diabetic control and diabetic groups when repeatedly administered orally with ethanolic extract. On the other hand, the aqueous extract brought down the TC value to 57% and the TG value to 37% of the diabetic control rats (p<0.05). CONCLUSIONS: The results suggested that the ethanolic extract of Chinese juniper berries possesses a potential hypoglycaemic effect while the aqueous extract has a potential hypolipidemic effect.  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