全文获取类型
收费全文 | 104644篇 |
免费 | 8724篇 |
国内免费 | 6122篇 |
专业分类
耳鼻咽喉 | 1113篇 |
儿科学 | 1544篇 |
妇产科学 | 2304篇 |
基础医学 | 12408篇 |
口腔科学 | 1949篇 |
临床医学 | 14009篇 |
内科学 | 16577篇 |
皮肤病学 | 894篇 |
神经病学 | 5671篇 |
特种医学 | 3529篇 |
外国民族医学 | 42篇 |
外科学 | 11236篇 |
综合类 | 14794篇 |
现状与发展 | 23篇 |
一般理论 | 20篇 |
预防医学 | 6116篇 |
眼科学 | 2865篇 |
药学 | 10702篇 |
56篇 | |
中国医学 | 4838篇 |
肿瘤学 | 8800篇 |
出版年
2024年 | 280篇 |
2023年 | 1503篇 |
2022年 | 3802篇 |
2021年 | 4974篇 |
2020年 | 3521篇 |
2019年 | 3241篇 |
2018年 | 3543篇 |
2017年 | 2923篇 |
2016年 | 2842篇 |
2015年 | 4407篇 |
2014年 | 5616篇 |
2013年 | 5006篇 |
2012年 | 7521篇 |
2011年 | 8264篇 |
2010年 | 4976篇 |
2009年 | 3815篇 |
2008年 | 5268篇 |
2007年 | 5524篇 |
2006年 | 5404篇 |
2005年 | 5698篇 |
2004年 | 3830篇 |
2003年 | 3398篇 |
2002年 | 3005篇 |
2001年 | 2440篇 |
2000年 | 2650篇 |
1999年 | 2703篇 |
1998年 | 1578篇 |
1997年 | 1481篇 |
1996年 | 1308篇 |
1995年 | 1161篇 |
1994年 | 982篇 |
1993年 | 635篇 |
1992年 | 998篇 |
1991年 | 805篇 |
1990年 | 684篇 |
1989年 | 600篇 |
1988年 | 593篇 |
1987年 | 529篇 |
1986年 | 420篇 |
1985年 | 330篇 |
1984年 | 208篇 |
1983年 | 159篇 |
1982年 | 85篇 |
1981年 | 98篇 |
1980年 | 83篇 |
1979年 | 115篇 |
1978年 | 54篇 |
1977年 | 56篇 |
1975年 | 44篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 4 毫秒
91.
Indomethacin promotes germinal matrix microvessel maturation in the newborn beagle pup. 总被引:1,自引:0,他引:1
L R Ment W B Stewart T A Ardito E Huang J A Madri 《Stroke; a journal of cerebral circulation》1992,23(8):1132-1137
BACKGROUND AND PURPOSE: Although indomethacin has been demonstrated to prevent germinal matrix and intraventricular hemorrhage in clinical and animal studies, the mechanism of action of this agent to prevent hemorrhage remains unclear. Previous studies have demonstrated both that the microvessels in the germinal matrix of newborn beagle pups undergo basement membrane maturation during the first 4 postnatal days and that indomethacin may promote laminin deposition in tumor cell culture systems. METHODS: We employed the newborn beagle pup model to test the hypothesis that indomethacin may stimulate laminin deposition in germinal matrix microvessels. Newborn pups were randomized to receive either 0.1 mg/kg/dose i.p. indomethacin or an equal volume of saline diluent. Pups received doses of study medication once a day for 1, 2, or 3 days and were studied on postnatal days 1, 2, 3, or 4. Pups were anesthetized and systemically perfused with buffered formalin; the brains were removed and prepared for immunohistochemical study. RESULTS: Sections stained with Bandeiraea lectin demonstrated that there was no difference in germinal matrix vessel density among the postnatal ages studied; similarly, there were no differences in vessel density between saline- and indomethacin-treated animals at any postnatal age. Quantification of germinal matrix stained intensity by confocal microscopy demonstrated significant increases in indomethacin-treated pups for both laminin staining at postnatal days 2 (p = 0.05) and 3 (p = 0.0009) and type V collagen staining at postnatal day 2 (p = 0.011). Although staining for beta 1 integrins increased across postnatal ages, there were no differences between saline- and indomethacin-treated animals. CONCLUSIONS: These data suggest that indomethacin may stimulate basement membrane deposition in the germinal matrix microvessels of newborn beagle pups to prevent germinal matrix and/or intraventricular hemorrhage. 相似文献
92.
Joen-Rong sheu Chao-Hsin Lin Jih-Luan chung Che-Ming Teng Tur-Fu Huang 《Thrombosis research》1992,66(6):679-691
Triflavin, an Arg-Gly-Asp (RGD)-containing peptide, purified from snake venom of Trimeresurus flavoviridis, inhibits human platelet aggregation through the blockade of fibrinogen binding to fibrinogen receptors associated with glycoprotein IIb/IIIa complex. In this report, we examined the effect of triflavin on tumor cells (human hepatoma J-5)-induced platelet aggregation (TCIPA) of heparinized platelet-rich plasma (PRP). ADP-scavenger agents, apyrase (10 U/ml) and creatine phosphate (5 mM)/creatine phosphokinase (5 U/ml) did not inhibit TCIPA while hirudin (5u/ml) completely inhibited it. J-5 cells initially induced platelet aggregation, then blood coagulation occurred. J-5 cells concentration-dependently shortened the recalcification time of normal as well as Factor VIII, IX-deficient human plasmas, while it was inactive at shortening the recalcification time of Factor VII-deficient plasma, suggesting J-5 cells induced platelet aggregation through activation of extrinsic pathway, leading to thrombin formation as evidenced by the amidolytic activity on S-2238 by expressing tissue factor-like activity. Triflavin inhibited TCIPA in a dose-dependent manner (IC50, 0.02 μM). When compared on molar ratio, triflavin was approximately 30,000 times more potent than GRGDS (IC50,0.58 mM). On the other hand, GRGES showed no significant effect on TCIPA, even its concentration was raised to 4 mM. Additionally, the monoclonal antibodies, raised against glycoprotein IIb/IIIa complex (i.e., 7E3 and 10 E5) inhibited J-5 TCIPA. In conclusion, we suggest the inhibitory effect of triflavin on J-5 TCIPA may be chiefly mediated by the binding of triflavin to the fibrinogen receptor associated with glycoprotein IIb/IIIa complex on platelet surface membrane. 相似文献
93.
To investigate the effects of dietary protein and polyunsaturated fat levels on tissue lipid peroxidation and antioxidative enzymes, Long-Evans male weanling rats were fed either an 8% lactalbumin diet containing 2% (L2), 5% (L5), 10% (L10), 15% (L15) or 20% (L20) soybean oil or a 20% lactalbumin diet containing 5% (N5) or 20% (N20) soybean oil for 8 weeks. The tissue thiobarbituric acid-reactive substances (TBARS) concentrations of the L2 group were similar to those of the N5 group except in plasma in which they were higher. The L5 group generally showed tissue TBARS concentrations comparable to the N20 group. Gradually increasing the dietary soybean oil level in the low protein diet further increased the tissue TBARS concentrations. The L20 group had significantly higher TBARS in RBC, liver, heart, kidney and muscle than the N20 group. The low protein-fed groups had lower activities of glutathione peroxidase (EC 1.11.1.9), superoxide dismutase (EC 1.15.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) in liver and catalase (EC 1.11.1.6) in RBC than the N5 group. Compared with the N5 group, the N20 group also showed higher TBARS concentrations and lower activities of certain antioxidative enzymes in some tissues. The antioxidative enzyme activities decreased more drastically with the increasing dietary soybean oil level in the low protein-fed groups than in those fed a normal level of protein. Supplementation of 150 mg/kg of all-rac-alpha-tocopheryl acetate to the L15 diet slightly decreased the TBARS in plasma, heart and liver and restored the depressed activities of RBC superoxide dismutase and catalase. The results indicated that insufficiency of dietary protein aggravates the enhanced production of TBARS and the reduced activities of antioxidant enzyme in rats fed a high soybean oil diet. 相似文献
94.
95.
目的分析胸部X线及CT影像征象在支气管结核临床诊断中的价值和意义。方法收集本院经病理及电子支气管镜证实为支气管结核105例,对照其胸部X线与CT表现进行回顾性分析。结果105例患者中,胸部X线显示伴有肺内结核灶77例,气管狭窄、肺叶不张分别为51例和49例,未见异常表现17例。胸部CT扫描对气管狭窄及肺叶不张检出率明显提高,分别为72例和61例,且能观察到气管内壁情况及狭窄或阻塞后肺野情况,伴肺内结核灶79例,无异常改变只有8例。结论提高对支气管结核的影像学认识,能有效地提高临床诊断准确率。 相似文献
96.
Chung-Ho Chen Chao-San Chang Chi-Hsin Hsieh Yu-Chuan Tseng Yee-Shyong Shen I-Yueh Huang Chia-Fu Yang Chun-Ming Chen 《Journal of oral and maxillofacial surgery》2006,64(8):1209-1213
PURPOSE: Various types of temporary implants have been introduced to serve as orthodontic anchorage. The hypothesis of this study is that microimplants of 1.2 mm diameter can be used as orthodontic anchors, and that their success is related to their length. The aim of this study is to determine the incidence of anchor retention after orthodontic force application for moving teeth, and to determine the relationship of microimplant length to retention rate. METHODS: Fifty-nine microimplants (diameter: 1.2 mm) were placed in 29 patients as orthodontic anchorages. After 2 weeks of microimplant placement, a force of 100 to 200 g was loaded with an elastometric chain or NiTi coil spring. Risk factors were characterized as to why a microimplant may fail, and Fisher's exact test was used for statistical analysis. RESULTS: Nine microimplants were removed and the overall success rate was 84.7%. Exploring the causes for failure, we found significant differences between the length of microimplants and success rate; 6 mm was 72.2% and 8 mm was 90.2%. CONCLUSIONS: The results suggest that microimplants are suited as an alternative orthodontic anchorage. We recommend that 8-mm microimplants are preferable to 6-mm. 相似文献
97.
The immediate, short-term and long-term depressor effects, the immediate effects on cardiac functions in grade II and grade III vascular hypertension, and the effects on angiotensin II in grade III vascular hypertension by acupuncture at otoacupoint Heart were studied in 30 cases of vascular hypertensive patients. The immediate depressor effect of acupuncture at otoacupoint Stomach was also recorded for comparison. It was found that acupuncture at otoacupoint Heart produced marked immediate depressor effect, and the short-term effective rate was 100%, the long-term effective rate was 63.3%, as well as evident immediate effects on cardiac functional activities in grade II and grade III hypertension and marked effects on angiotensin II in grade III hypertension. Acupuncture at otoacupoint Stomach produced no depressor effect on vascular hypertension. 相似文献
98.
Y Y Ng W L Lin T W Chen B C Lin S H Tsai C C Chang T P Huang 《American journal of nephrology》1992,12(4):268-270
Although cold syrup containing dextromethorpan bromide is widely administered, the bromism due to cold syrup has not been reported. We report a patient who had negative anion gap with hyperchloremia and conscious loss because of daily intake of cold complex syrup (containing dextromethorphan bromide 0.4 mg/ml, acetaminophen 8.33 mg/ml) for headache for 4-5 years. The bromide content in cold complex syrup resulted in serum levels of bromide that interfered with the automated analyzers for chloride content. When conscious change is due to bromism, hemodialysis instead of forced hydration and diuresis should be performed immediately. Therefore, patients with a markedly negative anion gap with hyperchloremia should be considered as having halide intoxication. 相似文献
99.
男性慢性胃炎患者人格特征初探 总被引:4,自引:0,他引:4
本文采用卡氏十六种人格因素量表,对纤维胃十二肠镜和活体组织病理检查确诊,剔除可能影响调查的疾患之后的56例慢性胃炎患者做了测查,结果与中国男性成人常模对照,提示男性慢性胃炎患者的主要人格特征有:严谨、保守、忧郁、紧张、顺从、依赖、有焦虑倾向,非内向个性,不属于心理不健康人群,而与消化性溃疡个性特征有所不同,但是,矫治其人格缺损及属必要。 相似文献
100.
城市污灌废水的致突变性检测及色谱/质谱分析 总被引:1,自引:0,他引:1
应用Ames致突变试验,对比研究了武汉市易家墩、黄孝河污灌区污灌废水与土壤的致突变性。同时应用色谱/质谱(GC/MS)分析技术。测定了主要污水中有机污染物的化学组成。结果表明:罗家渠废水的致突变活性最强;受各条污水灌溉的土壤的致突变活性顺序与相应废水的强弱顺序一致;罗家渠废水中致突变致癌物主要是萘、联苯等。 相似文献