全文获取类型
收费全文 | 37129篇 |
免费 | 2078篇 |
国内免费 | 821篇 |
专业分类
耳鼻咽喉 | 367篇 |
儿科学 | 649篇 |
妇产科学 | 1127篇 |
基础医学 | 8270篇 |
口腔科学 | 6307篇 |
临床医学 | 2024篇 |
内科学 | 3072篇 |
皮肤病学 | 517篇 |
神经病学 | 1803篇 |
特种医学 | 675篇 |
外科学 | 1923篇 |
综合类 | 3773篇 |
预防医学 | 3639篇 |
眼科学 | 316篇 |
药学 | 3392篇 |
8篇 | |
中国医学 | 353篇 |
肿瘤学 | 1813篇 |
出版年
2023年 | 430篇 |
2022年 | 777篇 |
2021年 | 962篇 |
2020年 | 1017篇 |
2019年 | 986篇 |
2018年 | 974篇 |
2017年 | 1075篇 |
2016年 | 1095篇 |
2015年 | 1186篇 |
2014年 | 2115篇 |
2013年 | 2243篇 |
2012年 | 1908篇 |
2011年 | 2234篇 |
2010年 | 1765篇 |
2009年 | 1762篇 |
2008年 | 1860篇 |
2007年 | 1790篇 |
2006年 | 1579篇 |
2005年 | 1295篇 |
2004年 | 1153篇 |
2003年 | 1100篇 |
2002年 | 840篇 |
2001年 | 784篇 |
2000年 | 709篇 |
1999年 | 631篇 |
1998年 | 677篇 |
1997年 | 616篇 |
1996年 | 628篇 |
1995年 | 621篇 |
1994年 | 579篇 |
1993年 | 495篇 |
1992年 | 470篇 |
1991年 | 404篇 |
1990年 | 371篇 |
1989年 | 313篇 |
1988年 | 300篇 |
1987年 | 242篇 |
1986年 | 212篇 |
1985年 | 285篇 |
1984年 | 263篇 |
1983年 | 165篇 |
1982年 | 165篇 |
1981年 | 154篇 |
1980年 | 131篇 |
1979年 | 121篇 |
1978年 | 94篇 |
1977年 | 79篇 |
1976年 | 74篇 |
1975年 | 57篇 |
1974年 | 62篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Kuntal Patel Deemesh Oudit G Ross Caroline Nicolson AJ Howcroft 《CANADIAN JOURNAL OF PLASTIC SURGERY》2005,13(4):207-208
A lump on the midface of a child can pose as a diagnostic dilemma. There is a wide variety of possible differential diagnoses, ranging from simple benign conditions such as a sebaceous cyst, dermoid cyst, lipoma, neuroma and neurofibroma, to potentially devastating conditions such as odontogenic myxoma.A case of a child in which the formulation of a definite diagnosis was clinically and histologically challenging is presented. 相似文献
112.
目的观察左旋肉毒碱(L-carnitine,L-C)对人成骨细胞增殖和凋亡的作用。方法以3H掺入法(3H-TdR)测定左旋肉毒碱对人成骨细胞增殖的影响;以吖啶橙/溴化乙啶染色和细胞凋亡ELISA(酶联免疫吸附法)试剂盒测定左旋肉毒碱对人成骨细胞凋亡的影响;以免疫印记法检测左旋肉毒碱干预前后活化型Caspase-3、-9蛋白质表达水平的改变。结果10~100mmol/L左旋肉毒碱能促进人成骨细胞增殖。吖啶橙/溴乙啶染色法示100mmol/L左旋肉毒碱干预使人成骨细胞凋亡细胞明显减少。ELISA结果示10~100mmol/L左旋肉毒碱干预可显著抑制人成骨细胞凋亡。10~100mmol/L左旋肉毒碱干预可抑制无血清饥饿诱导的人成骨细胞caspase-3、9活化增加。结论左旋肉毒碱促进人成骨细胞增殖,并通过下调Caspase-3、-9的活化抑制人成骨细胞凋亡。 相似文献
113.
局部注射VEGF对大鼠正畸牙齿移动的影响 总被引:3,自引:1,他引:2
目的:观察局部注射重组鼠的血管内皮生长因子(rrVEGF)对大鼠正畸牙齿移动的影响,探讨VEGF在正畸牙齿移动中的作用机制。方法:45只雄性SD大鼠,牵引其上颌第一磨牙近中移动,实验中分别将rrVEGF及生理盐水注射入实验组及对照组大鼠右侧上颌第一磨牙腭侧的骨粘膜下,于实验前3天开始注射,每3天一次。分别在加力l、3、7、14、2l天后记录上颌第一磨牙移动距离。然后将各组动物处死,用HE染色观察牙周组织变化情况并采用免疫组织化学方法对组织中表达的VEGF进行分析。结果:实验组大鼠压力侧破骨细胞教和成骨细胞数在实验全过程中均多于对照组,而且,实验组大鼠牙齿移动距离明显大于对照组。结论:进一步证实VEGF作为旁分泌因子,参与了牙齿移动过程中的牙周组织改建,内源性VEGF和注射VEGF都使牙齿移动量显著增加。因此,VEGF在正畸牙齿移动的机制中具有重要意义。 相似文献
114.
In enamel fluorosis model rats treated with sodium fluoride, secretory ameloblasts of incisor tooth germs exhibited disruption
of intracellular trafficking. We examined whether heterotrimeric G proteins participated in the disruption of vesicular trafficking
of the secretory ameloblast exposed to fluoride, using immunoblotting and pertussis toxin (IAP)-induced adenosyl diphosphate
(ADP)-ribosylation for membrane fractions of the cell. Immunoblotting of crude membranes, post supernatants of the ameloblast,
with anti-Gi3/o and anti-Gs antibodies showed that Gi3 or Go proteins existed in the secretory ameloblast, but Gs protein did not. Immunoblotting of the subcellular membrane fractions indicated that the Gi3 or Go proteins were located in the Golgi membrane, but were not in the rough endoplasmic reticulum (rER) membrane. Autoradiograph
of IAP-induced ADP-ribosylation, however, showed the existence of IAP-sensitive G proteins both in rER and Golgi membranes.
Fluoride treatment decreased the G proteins bound to both membranes. These findings indicate that different G proteins, both
of which are IAP-sensitive, are present in the rER and Golgi apparatus, and suggest that these G proteins participate in the
disturbance of intracellular transport of the secretory ameloblast exposed to fluoride.
Received: 24 June 1998 / Accepted: 8 September 1998 相似文献
115.
The aim of the present study was to evaluate the clinical and radiologic results of 20 autotransplantations of impacted canines performed in the Orthodontic and Pedodontic Department of the University of Geneva between 1979 and 1988. The sample, divided into two different age groups (group A: 13–20 years; group B: 20–48 years), demonstrated persistence of pulp vitality in 80% of the cases in group A, whereas routine endodontic treatment was instituted in all cases of group B. Periodontal healing was noted in 90% of the cases in group A, and in 70% of the cases in group B. The present clinical and radiologic data indicate that impacted canines can be transplanted at any age with good prognosis and are an alternative to orthodontic repositioning in selected cases of canine impaction. 相似文献
116.
Summary Human fibrin glue (Tissucol) is a plasma-derived compound endowed with adhesive and hemostatic properties and possessing a specific local anti-infection function mediated through activation of nonspecific immunity elements. The aim of this study is to show that in patients who have undergone prolonged reconstructive plastic surgery following cancer resection, Tissucol decreases infectious complications as compared to a control group. Between June 1985 and February 1988, 51 subjects were treated with fibrin glue during reconstruction operations. Analysis of the results showed that Tissucol produced a statistically significant reduction both of immediate complications, such as inflammation and partial separation of the surgical wound, and of delayed complications, such as scar hypertrophy and cutaneous fistulae. In conclusion, patients treated with Tissucol showed a better quality of surgical wound, a more rapid postoperative functional recovery and consequently a decrease in the duration of hospitalization. 相似文献
117.
118.
人碱性成纤维细胞生长因子基因在大肠杆菌中的克隆与表达 总被引:1,自引:0,他引:1
应用DNA重组技术将编码人碱性成纤维细胞生长因子(bbFGF)的基因克隆至原核高效表达质粒pBV_(221)的启动子下游。SDS-SAGE、ELISA和NTT活性监测结果表明:该重组质粒pBV-hbFGF在大肠杆菌DH5α中,经42℃诱导后,可表达出有较高生物活性的hbFGF。 相似文献
119.
P. Lekic D. Kenny H. K. Moe E. Barrettt C. A. G. McCulloch 《Journal of periodontal research》1996,31(4):294-300
The survival rate of avulsed permanent teeth following replantation is affected primarily by the duration of the extra-alveolar period and the nature of the storage conditions. These factors are believed to strongly affect the viability of periodontal ligament (PL) cells but in vitro assays of cell viability based on vital dye assays are only weakly correlated with the tooth survival rate after replantation. The aim of the present study was to examine the relative dependence of cell membrane integrity, attachment and clonogenic capacity of human PL cells on the temperature and duration of the extra-alveolar period and the type of storage medium. Twenty-four premolar teeth were extracted for orthodontic reasons from 9 patients 11–18 years of age. Teeth were maintained at 4°C or 23°C for 15, 30, 60 or 120 min in either milk or dry conditions. Cell membrane integrity was determined by BCECF/AM dye inclusion. Plating efficiency was determined by measurement of cell attachment at 3 and 6 h. The clonogenic capacity of progenitor cells was estimated by limiting dilution and colony counts. For all assays teeth stored in milk at 4°C showed the highest percentages of BCECF positive, attached cells with clonogenic capacity. Increased storage time (15–120 min) was associated with a 50% relative reduction of BCECF staining and a 5-fold relative reduction of cell attachment regardless of storage conditions. However, the clonogenic capacity of progenitor cells decreased 25-fold over the same duration of storage. These data demonstrate that in vitro assays of clonogenic capacity are much more sensitive to extra-oral storage time and storage conditions than dye inclusion or cell attachment. We suggest that in comparison with in vitro measures of cell membrane integrity, the clonogenic capacity of PL cells is more closely linked to tooth survival rate, probably reflecting the capacity of PL progenitor cells to recolonize the root surface after replantation. 相似文献
120.
Christopher A. Buneo Jyl Boline John F. Soechting Richard E. Poppele 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1995,104(3):467-479
We investigated, by using simulations, possible mechanisms responsible for the errors in the direction of arm movements exhibited by deafferented patients. Two aspects of altered feedforward control were evaluated: the inability to sense initial conditions and the degradation of an internal model. A simulation which assumed no compensation for variations in initial arm configuration failed to reproduce the characteristic pattern of errors. In contrast, a simulation that assumed random variability in the generation of joint torque resulted in a distribution of handpaths which resembled some aspects of the pattern of errors exhibited by deafferented patients. 相似文献