全文获取类型
收费全文 | 21938篇 |
免费 | 1787篇 |
国内免费 | 2376篇 |
专业分类
耳鼻咽喉 | 359篇 |
儿科学 | 264篇 |
妇产科学 | 66篇 |
基础医学 | 1879篇 |
口腔科学 | 916篇 |
临床医学 | 1780篇 |
内科学 | 5086篇 |
皮肤病学 | 99篇 |
神经病学 | 168篇 |
特种医学 | 598篇 |
外科学 | 3682篇 |
综合类 | 3842篇 |
预防医学 | 844篇 |
眼科学 | 38篇 |
药学 | 1815篇 |
10篇 | |
中国医学 | 827篇 |
肿瘤学 | 3828篇 |
出版年
2023年 | 256篇 |
2022年 | 556篇 |
2021年 | 768篇 |
2020年 | 684篇 |
2019年 | 583篇 |
2018年 | 553篇 |
2017年 | 516篇 |
2016年 | 687篇 |
2015年 | 849篇 |
2014年 | 1650篇 |
2013年 | 1512篇 |
2012年 | 1438篇 |
2011年 | 1425篇 |
2010年 | 1224篇 |
2009年 | 1213篇 |
2008年 | 1352篇 |
2007年 | 1356篇 |
2006年 | 1284篇 |
2005年 | 1091篇 |
2004年 | 755篇 |
2003年 | 696篇 |
2002年 | 635篇 |
2001年 | 617篇 |
2000年 | 582篇 |
1999年 | 471篇 |
1998年 | 397篇 |
1997年 | 389篇 |
1996年 | 364篇 |
1995年 | 267篇 |
1994年 | 280篇 |
1993年 | 209篇 |
1992年 | 160篇 |
1991年 | 172篇 |
1990年 | 149篇 |
1989年 | 135篇 |
1988年 | 97篇 |
1987年 | 82篇 |
1986年 | 62篇 |
1985年 | 68篇 |
1984年 | 66篇 |
1983年 | 35篇 |
1982年 | 59篇 |
1981年 | 40篇 |
1980年 | 60篇 |
1979年 | 61篇 |
1978年 | 37篇 |
1977年 | 31篇 |
1976年 | 36篇 |
1975年 | 18篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
91.
用静脉内、肌肉内及鼻腔内三种给药途径给10只狗按5mg/kg用40mg/ml的庆大霉素,并使用双波长色谱扫描法测定0~180分钟血清庆大霉素的浓度,比较其生物利用度。发现鼻内给药的生物利用度为静脉注射的80.5%,肌肉注时为42%。鼻腔用药后10~30分钟血清浓度达到高峰,范围在3.7~6.6μg/ml,半衰期长达3小时左右,表明鼻粘膜对庆大霉素有良好的通透性,可使其迅速吸收入血,并能在血中长时间维持有效浓度。 相似文献
92.
胃癌组织COX-2的表达及其与细胞增殖和凋亡的关系 总被引:8,自引:1,他引:7
目的 :探讨环氧化酶 - 2 (cyclooxygenase - 2 ,COX - 2 )在胃癌组织中的表达与癌细胞增殖和凋亡的关系。 方法 :采用免疫组织化学的方法检测 4 3例胃癌患者COX - 2和增殖细胞核抗原 (PCNA)的表达 ,用TUNEL法检测原位细胞凋亡的情况。分别计算细胞增殖指数 (MI)和凋亡指数 (AI)。结果 :胃癌组织COX - 2表达的阳性率为 6 0 .4 7% ,明显高于对照组 (P <0 .0 1)。COX - 2的高表达与胃癌淋巴结的转移和临床分期有关 ,与肿瘤大小、浸润深度、分化程度均无关。COX - 2阳性胃癌组中MI高于COX - 2阴性胃癌组 ,而AI却低于COX - 2阴性胃癌组 (P均 <0 .0 1)。结论 :COX - 2的过度表达可促进胃癌细胞增殖、抑制细胞凋亡 ,在胃癌的发生、发展过程中起着重要的作用。 相似文献
93.
Background: Laparoscopic surgery has been successfully applied to several gastrointestinal procedures. Although the totally laparoscopic
gastrectomy is feasible, tactile sensation and manipulation of the organ as well as the lesion are decreased when compared
to open surgery. The Dexterity Pneumo Sleeve is a new device which allows the surgeon to insert a hand into the abdominal
cavity while preserving the pneumoperitoneum. This device was used for patients who underwent laparoscopic gastric surgery.
Methods: The first patient presented with a non-Hodgkin's lymphoma of the stomach. A laparoscopically assisted distal gastrectomy
was performed with Roux-en-Y reconstruction. The second patient had a 5-cm leiomyoma involving the greater curve of the stomach,
and this device was used for manipulation of the tumor. The last patient suffered from morbid obesity with its associated
medical complications and a ventral hernia. The Sleeve was applied at the hernia site and a laparoscopically assisted gastric
bypass was performed.
Results: The Pneumo Sleeve was useful in these cases for tactile localization of the tumor and for retraction and manipulation of
the stomach and surrounding upper abdominal organs.
Conclusions: The utilization of this device resulted in a more easily performed dissection, resection, and anastomosis and was felt to
decrease operation time.
Received: 18 September 1996/Accepted: 26 December 1996 相似文献
94.
The Workup for Bariatric Surgery Does Not Require a Routine Upper Gastrointestinal Series 总被引:1,自引:0,他引:1
Andrew J Ghassemian Kenneth G MacDonald MD Paul G Cunningham MD Melvin Swanson PhD Brenda M Brown MRA Patricia G Morris BSN Walter J Pories MD 《Obesity surgery》1997,7(1):16-18
Background: Morbid obesity is a serious disease that afflicts over five million Americans, threatening their health with such
co-morbidities as diabetes, arthritis, pulmonary failure and stroke. Surgery is the only effective therapy, providing long-term
control of weight, diabetes, pulmonary failure, and hypertension for as long as 14 years. Because the operation presents a
major expense, this study examined whether X-ray examination of the gut could be omitted safely as a cost-saving measure.
Methods: The records of 814 consecutive morbidly obese patients who underwent gastric bypass were reviewed to determine: (1)
whether these individuals had undergone an upper gastro-intestinal (GI) series, and (2) if these studies influenced therapy
or caused cancellation or postponement of surgery. Results: Of the 814 patients, 657 (80.7%) underwent a preoperative GI radiography.
Of these examinations, 393 (59.8%) were normal, with the following abnormalities in the remaining 264: hiatal hernia, 164;
esophageal reflux, 39; Schatzki's ring, 18; small bowel diverticula, four; renal stones, four; malrotation, three; gall stones,
two; pyloric ulcer, one; possible pelvic mass, one; calcified leiomyoma, one; and dysphagial lusoria, one. None of these findings
resulted in cancellation or a delay in surgery. Conclusions: The upper GI series can be safely omitted from the routine preoperative
evaluation of patients undergoing gastric bypass. At a cost of $741.00 per examination, this change represents significant
potential savings. Similar evaluations of other routine preoperative tests may well provide a better basis for the evaluation
of these complex patients. 相似文献
95.
目的 探讨环氧化酶2(COX-2)基因启动子区甲基化水平和蛋白表达与胃黏膜病变的关系,并对其相关的影响因素进行研究.方法 以1201例患有不同胃黏膜病变的高危人群为研究对象,采用免疫组织化学方法榆测COX-2表达,用亚硫酸氢钠-变性高效液相色谱(DHPLC)对COX-2启动子甲基化率进行定量分析,采用13C尿素呼气实验(13C-UBT)对幽门螺旋杆菌(H priori)感染状况进行测定.结果 COX-2甲基化率中位数随胃黏膜病变的加重逐渐升高,在浅表性胃炎和慢性萎缩性胃炎(SG/CAG)、肠上皮化生(IM)及不确定性异型增生和异璎增生(Ind DYS/DYS)病变中分别为10.6%、11.8%、13.8%,各病变组之间差异有统计学意义(X2=8.312,P=0.016).分层分析显示,在H pylori感染阴性病例中,COX-2甲基化率仍随病变加重明显升高,在SG/CAG、IM、Ind DYS/DYS病变中其中位数分别为8.8%、10.6%、14.1%(X2=6.629,P=0.036).进一步分析发现,COX-2甲基化率随着COX-2表达强度的增强而降低,由COX-2弱阳性表达的13.3%降至强阳性表达的7.6%(X2=10.400,P=0.015).结论 COX-2启动子甲基化水平与胃黏膜病变程度及H pylori感染状况密切相关,并与COX-2表达强度呈负相关,说明COX-2启动子区异常甲基化可能在胃黏膜病变的演变过程中起重要作用. 相似文献
96.
正常人口腔粘膜不同部位表面感觉的测试 总被引:1,自引:0,他引:1
目的 建立正常人口腔粘膜不同部位表面感觉的正常参考值,并测试各年龄组感觉值是否存在差异。方法 利用动静两点辨别觉试验,测试90例健康人口腔粘膜不同部位的表面感觉。结果 舌尖感觉功能最好,其次为舌背、舌腹、颊粘膜、口底和硬腭。健康人的口腔粘膜不同部位的表面感觉随着年龄增长有显著性变化。结论 口腔粘膜不同部位感觉辨别力存在差异,健康人口底、舌腹、舌背、颊和硬腭粘膜感觉功能有增龄性变化。 相似文献
97.
理气类中药对大鼠离体胃平滑肌条的作用 总被引:9,自引:0,他引:9
目的:观察理气类中药对大鼠离体胃平滑肌条运动的影响。方法:将肌条放置在灌流肌槽中,用生理记录仪记录肌条的收缩活动。结果:陈皮、枳实对胃各部位平滑肌条均为抑制效应,香附、薤白、木香、柿蒂、乌药对胃底肌条为兴奋效应,但对其他部位肌条则表现为兴奋或抑制不同的效应,沉香仅降低胃窦环行肌收缩波平均振幅,对其他肌条无影响。结论:理气类中药对大鼠离体胃平滑肌条既有兴奋作用,也有抑制作用。 相似文献
98.
rhGM-CSF对小鼠口腔粘膜损伤的防治作用 总被引:1,自引:0,他引:1
目的:探讨rhGM-CSF促进口腔腔溃愈合的作用机制。方法:取体外培养的胎儿口腔粘膜成纤维细胞,用rhGM-CSF刺激成纤维细胞后第2、4、6天用细胞计数及^3H-胸腺嘧啶掺入法(^3H-TdR)测定其增殖情况,结果rhGM-CSF对胎儿口腔粘膜成纤维细胞增殖及DNA合成有刺激作用,在80-100ng/ml时,细胞生长达到最佳状态,过高浓度rhGM-CSF的刺激作用反而下降。结论:rhGM-CSF可以通过刺激成纤维细胞增殖及DNA合成促进口腔溃疡愈合。 相似文献
99.
R. L. Cabrini A. E. Schwint A. Mendez F. Femopase H. Lanfranchi M. E. Itoiz 《Journal of oral pathology & medicine》1992,21(6):275-279
A morphometric study of nucleolar organizer regions (NOR) was performed to analyze their distribution, volume, number and shape in the different strata of human normal oral mucosa epithelium and papilloma and in squamous cell carcinoma employing microphotographs of silver-stained paraffin sections. The different NOR-related parameters evidenced significant differences between normal mucosa, papilloma and squamous cell carcinoma. The functional polarity of normal mucosa epithelium and of papilloma is also evidenced in terms of NOR-related parameters. The discriminative value of certain NOR parameters was demonstrated. 相似文献
100.
S. Chooramani Gopal A. N. Gangopadhyaya S. N. Gupta G. D. Singhal 《Pediatric surgery international》1991,6(6):438-441
Our experience of single-stage repair of severe hypospadias (penoscrotal, scrotal, and perineal) in 30 children using urinary bladder mucosa for urethroplasty is reported. These children had severe chordee, small prepuce, and often ventral transposition of the penis with bifid scrotum where Devine and Horton, Asopa, or Duckett techniques are not so suitable. The graft uptake was uniformly satisfactory. Ten patients had complications; most of the fistulae healed spontaneously. Surgical intervention was required in 2 cases only: 1 for a fistula and another for a stricture with fistula. Meatal stenosis, seen in 4 cases, led to delayed distal fistulae in 2, which healed spontaneously with meatal dilatation. Regular dilatation of the external meatus is recommended to prevent this problem. 相似文献