全文获取类型
收费全文 | 219660篇 |
免费 | 20565篇 |
国内免费 | 15418篇 |
专业分类
耳鼻咽喉 | 1901篇 |
儿科学 | 2191篇 |
妇产科学 | 2979篇 |
基础医学 | 26544篇 |
口腔科学 | 3685篇 |
临床医学 | 30822篇 |
内科学 | 32952篇 |
皮肤病学 | 2226篇 |
神经病学 | 12383篇 |
特种医学 | 8227篇 |
外国民族医学 | 138篇 |
外科学 | 21727篇 |
综合类 | 35415篇 |
现状与发展 | 55篇 |
一般理论 | 19篇 |
预防医学 | 13168篇 |
眼科学 | 6695篇 |
药学 | 22710篇 |
194篇 | |
中国医学 | 12359篇 |
肿瘤学 | 19253篇 |
出版年
2024年 | 693篇 |
2023年 | 3551篇 |
2022年 | 9181篇 |
2021年 | 11502篇 |
2020年 | 8598篇 |
2019年 | 7540篇 |
2018年 | 8035篇 |
2017年 | 7086篇 |
2016年 | 6658篇 |
2015年 | 10255篇 |
2014年 | 12552篇 |
2013年 | 10702篇 |
2012年 | 16013篇 |
2011年 | 17955篇 |
2010年 | 10517篇 |
2009年 | 8187篇 |
2008年 | 11119篇 |
2007年 | 11095篇 |
2006年 | 11236篇 |
2005年 | 11329篇 |
2004年 | 7001篇 |
2003年 | 6617篇 |
2002年 | 5501篇 |
2001年 | 4940篇 |
2000年 | 5348篇 |
1999年 | 5692篇 |
1998年 | 3526篇 |
1997年 | 3500篇 |
1996年 | 2815篇 |
1995年 | 2608篇 |
1994年 | 2145篇 |
1993年 | 1377篇 |
1992年 | 1892篇 |
1991年 | 1597篇 |
1990年 | 1293篇 |
1989年 | 1091篇 |
1988年 | 1015篇 |
1987年 | 891篇 |
1986年 | 728篇 |
1985年 | 525篇 |
1984年 | 336篇 |
1983年 | 242篇 |
1982年 | 149篇 |
1981年 | 145篇 |
1980年 | 111篇 |
1979年 | 142篇 |
1978年 | 49篇 |
1977年 | 53篇 |
1975年 | 57篇 |
1974年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
目的 探讨血清骨膜蛋白(PN)和骨硬化蛋白(SOST)与老年 2 型糖尿病(T2DM)患者骨密度的关系。方法 选取2020年8月—2022年3月海南医学院第二附属医院收治的192例老年T2DM患者作为研究对象,依据骨密度值分为骨量正常组、骨量减少组及骨质疏松组,每组64例。比较3组患者的临床资料,血清PN、SOST、25羟维生素D3[25(OH)D3]、骨钙素(OST)及I型胶原氨基端前肽(PINP)水平。多因素Logistic回归分析影响老年T2DM患者骨质疏松发生的危险因素。绘制受试者工作特征(ROC)曲线,以ROC曲线下面积(AUC)评价血清PN、SOST及两者联合对老年T2DM患者骨质疏松的诊断价值。结果 骨量正常组、骨量减少组及骨质疏松组HbA1c、HDL-C、PN、SOST、25(OH)D3、OST及PINP水平比较,差异有统计学意义(P <0.05),骨质疏松组HbA1c、PN、SOST、OST及PINP水平高于骨量正常组和骨量减少组(P <0.05),骨质疏松组HDL-C、25(OH)D 相似文献
982.
作者根据现代免疫学观点,自1989年起采用自制中药“90增血剂”治疗ITP46例。期间,应用间接免疫荧光技术检测了患者外周血T淋巴细胞亚群,结果表明病例组全T细胞(CD_3)、T辅助/诱导细胞(CD_4)降低,T抑制/细胞毒细胞(CD_8)增高,CD_4/CD_8比值明显降低。治疗后,患者T亚群恢复常态,血小板数上升,骨髓产板型巨核细胞数增加,临床总有效率达91.2%,明显优于激素组(71.4%)。提示中药具有显著的疗效和良好的免疫调节作用。同时,动态观察ITP患者T细胞亚群的变化,对帮助临床判断治疗反应和预后有很大意义。 相似文献
983.
The effect of intrauterine devices (stainless steel ring, copper-T220 and levonorgestrel) on the DNA content in isolated human endometrial cells 总被引:1,自引:0,他引:1
P D Zhu H Z Luo J Cheng R H Xu Y F Liu W M Zheng G Y Song J H Chen Z H Zhou Y M Wu 《Contraception》1989,40(5):591-604
The effect of three different intrauterine devices on the DNA content in human endometrial cells has been studied in 29 women before and after the insertion of an IUD; a stainless steel ring (9 subjects), Copper-T220 (11 subjects) and a medicated IUD releasing levonorgestrel at a rate of 2 micrograms/day (9 subjects). The material was grouped into "bleeders" (having more than 8 days of bleeding and spotting per month) and "non-bleeders" (having less than 8 days of bleeding and spotting per month). The DNA content was assessed on isolated endometrial cells smeared from thin biopsies and the amount of DNA per cell nucleus was measured by means of a Feulgen microspectrophotometric method. No significant difference was found between the "bleeders" and the "non-bleeders" as to the DNA content. Nevertheless, when the total number of subjects were pooled together, a significant increase in the DNA content was found in the post-insertion specimens in the groups of women using the SS and the T-Cu IUDs. Furthermore, a significant decrease in the DNA content was also found when the specimens obtained after the insertion of the LNG IUD were compared with those obtained after 24 months' use of the stainless steel ring and the Copper-T220 device (p less than 0.01 and p less than 0.002, respectively). It is concluded that the insertion of an inert IUD or an T-Cu IUD, induces significant alterations in the DNA content of the human endometrium adjacent to the device, whereas the use of the LNG device does not significantly modify the DNA synthesis when used for 3-10 months. No correlation was found between the DNA content per cell and the number of days of bleeding and spotting. 相似文献
984.
Hippocampal EEG and unit activities were recorded after seizures were initiated withintracerebroventricular injection of kainic acid (KA) in rats. Three kinds of hippocampal unit re-sponses to KA were found:1. Positive units: These units were characterized by high frequency burst firing temporally coincidentwith each hippocampal EEG spike.2. Negative units: These units showed a cessation of firing during each EEG paroxysm.3. Indifferent units: These units showed no evident chanses coincident with EEG paroxysms.Most positive units were hippocampal complex spike cells which correspond histologically tohippocampal pyramidal cells, and most complex spike cells fired in positive bursts after KA treat-ment. In the early period after KA injection, the positive units were concentrated in CA3 area. It was suggested that the activities of positive units may be considered as the typical epileptiformhippocampal unit activity induced by KA, and the firing features of negative units ma be the resultof the influence of hippocampal inhibitory interneurons or the result of excessive cellulardepolarization, and that hippocampal pyramidal cells were more sensitive to the epileptogenic ef-fect of KA than hippocampal intemeurons, and some pyramidal cells in CA3, in particular,may serve as "epileptic pacemaker neurons " in KA-induced epileptogenesis. 相似文献
985.
Treatment of pain according to syndrome differentiation in 169 cases of liver cancer 总被引:1,自引:0,他引:1
In 169 cases with liver cancer pain, the therapeutic effects of TCM and the authors' "analgesic therapy of four steps" were analysed. The results were that most patients with advanced liver cancer had mild pain, and only a small number of patients (14.2%) had moderate or severe pain. By the first step analgesic therapy, 46.1% of the patients were relieved and with the second or third step of analgesic therapy, 93.5% of the patients were relieved, only 6.5% of the patients with grade III pain needed the fourth step therapy. With TCM treatment alone, the remission rate of grade I and grade II pain was 100% and 76.9% respectively. "Analgesic therapy of four steps" produced less side effects or addiction to narcotics. 相似文献
986.
This apparatus is designed in accordance with the doctrine and principles of traditional Chinese medicine and based on the theory of meridian and specific massage procedure in conjunction with the "Information Theory" and electron utilizing technique. It utilizes a programmed induction "Special Wave" to stimulate a series of acupuncture points, combined with administration of western drugs from a regime of "General Attack" treatment on the gallbladder stones, to enhance their evacuation. By stimulating the specific acupuncture points with this apparatus through the action of "Special Wave" strong contraction of the gallbladder can be elicitated. Experiments on dogs showed that under such stimulation the intra-gallbladder pressure can be increased 26 times, producing a jet of bile flow which facilitates the expulsion and evacuation of stones in the gallbladder. Method of use: first place a conductive rubber pad on the acupuncture point to be stimulated, then use a hand-held electrode to massage-stimulate the meridian. It is carried out forward and backward along the direction of meridian. The whole procedure is carried out under direct visualization with the help of ultrasonic B-scan. When dilatation of the common bile duct is observed, the hand-help electrode is used to perform push-compress massage on the meridian, and acupuncture points making the stones enter the common bile duct B-scan give proper orientation for the manipulation. This method has been tested clinically on 410 patients with good results. The evacuation rate of the gallbladder stones was 92.7% with complete evacuation achieved in 17.3%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
987.
Treatment of SV40-infected monkey cells with amonafide (benzisoquinolinedione), an intercalative antitumor drug, resulted in rapid accumulation of linearized intracellular SV40 DNA molecules that were protein linked. Studies using purified mammalian DNA topoisomerase II have shown that amonafide and its structural analogs interfere with the breakage-rejoining reaction of the enzyme by stabilizing a reversible enzyme-DNA "cleavable complex." Denaturation of the cleavable complex with sodium dodecyl sulfate resulted in DNA cleavage and the covalent association of topoisomerase II polypeptides with the cleaved DNA. Unwinding measurements indicate that amonafide is a DNA intercalator. These results suggest that amonafide and its structural analogs (e.g., mitonafide) represent a new class of intercalative topoisomerase II-active antitumor drugs. Different from other topoisomerase II-active antitumor drugs, amonafide and mitonafide induce specific DNA cleavage at a single major site on pBR322 DNA. The strong site specificity of amonafide may allow detailed characterization of the intercalator-stabilized, topoisomerase II-DNA cleavable complex. 相似文献
988.
989.
990.
一种新认识的胃癌癌前病变:人胃粘膜球样异型增生的组织病理学特点 总被引:1,自引:0,他引:1
Histopathologic features of globoid dysplasia of human gastric epithelium were described by means of observation of serial paraffin sections of 53 cases of globoid dysplasia. It was divided into three grades according to the architecture and cellular atypia. Penetration of outer layer globoid dysplastic cells through the basement membrane of "double layers structure" appeared in typical globoid dysplasia Grade III and infiltration of globoid dysplastic cells into stroma as well as the formation of incipient focus of signet ring cell carcinoma were described. The twinkling scene of infiltration of the globoid dysplastic cells into lamina propria through the basement membrane and the damage of basement membrane by globoid dysplastic cells were shown by Gordon Sweet's stain. Through the analysis of background lesions of the globoid dysplasia, a conclusion can be made that the globoid dysplasia might be an important precancerous lesion of the signet ring cell carcinoma of the stomach. 相似文献