全文获取类型
收费全文 | 107145篇 |
免费 | 4098篇 |
国内免费 | 217篇 |
专业分类
耳鼻咽喉 | 1527篇 |
儿科学 | 3151篇 |
妇产科学 | 3144篇 |
基础医学 | 14815篇 |
口腔科学 | 2730篇 |
临床医学 | 6365篇 |
内科学 | 25080篇 |
皮肤病学 | 2928篇 |
神经病学 | 8134篇 |
特种医学 | 2210篇 |
外国民族医学 | 2篇 |
外科学 | 13232篇 |
综合类 | 485篇 |
一般理论 | 26篇 |
预防医学 | 11970篇 |
眼科学 | 2327篇 |
药学 | 8144篇 |
中国医学 | 361篇 |
肿瘤学 | 4829篇 |
出版年
2023年 | 559篇 |
2022年 | 341篇 |
2021年 | 1633篇 |
2020年 | 847篇 |
2019年 | 1900篇 |
2018年 | 3333篇 |
2017年 | 1981篇 |
2016年 | 1893篇 |
2015年 | 2195篇 |
2014年 | 2334篇 |
2013年 | 3807篇 |
2012年 | 7007篇 |
2011年 | 7339篇 |
2010年 | 3522篇 |
2009年 | 2472篇 |
2008年 | 5949篇 |
2007年 | 6382篇 |
2006年 | 6269篇 |
2005年 | 6215篇 |
2004年 | 5943篇 |
2003年 | 5444篇 |
2002年 | 5228篇 |
2001年 | 3672篇 |
2000年 | 4068篇 |
1999年 | 3085篇 |
1998年 | 481篇 |
1996年 | 320篇 |
1992年 | 1269篇 |
1991年 | 1167篇 |
1990年 | 1086篇 |
1989年 | 974篇 |
1988年 | 886篇 |
1987年 | 902篇 |
1986年 | 828篇 |
1985年 | 801篇 |
1984年 | 589篇 |
1983年 | 459篇 |
1979年 | 595篇 |
1978年 | 346篇 |
1976年 | 321篇 |
1975年 | 350篇 |
1974年 | 536篇 |
1973年 | 491篇 |
1972年 | 431篇 |
1971年 | 393篇 |
1970年 | 470篇 |
1969年 | 429篇 |
1968年 | 407篇 |
1967年 | 382篇 |
1966年 | 315篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
13.
E García-Gómez S Vaca A Pérez-Méndez J Ibarra-Caballero V Pérez-Márquez V R Tenorio E Negrete-Abascal 《Avian pathology》2005,34(5):426-429
Gallibacterium anatis (previously named Pasteurella haemolytica-like) is considered a normal inhabitant of genital and upper respiratory tracts of healthy chickens, but it is also associated with different pathological conditions. Secreted metalloproteases from field and reference G. anatis cultures were obtained by methanol precipitation and were characterized. Proteins of molecular mass higher than 100 kDa showing proteolytic activity were observed in 10% polyacrylamide gels copolymerized with 1% bovine casein. They were active at alkaline pH, and inhibited by ethylenediamine tetraacetic acid. Their activity was stable at 50 degrees C, but partially inhibited at 60 degrees C, and totally inhibited at higher temperatures. Secreted proteins were able to degrade chicken IgG after 24 h of incubation, and cross-reacted with a polyclonal antibody against purified protease from Actinobacillus pleuropneumoniae. Secreted metalloproteases could play a role in infections caused by G. anatis. 相似文献
14.
A López Bernal D J Hansell S Alexander A C Turnbull 《British journal of obstetrics and gynaecology》1987,94(11):1052-1058
The production of progesterone from pregnenolone, of cortisol from cortisone and of prostaglandin E (PGE) under basal and arachidonic acid-stimulated conditions was measured in cells dispersed from chorion and decidua. The cells were obtained after delivery from four groups of women: following spontaneous labour at term (38-42 weeks gestation), at elective caesarean section at term before the onset of labour, after induced labour at term, and after uncomplicated preterm (27-36 weeks) labour. Chorionic cells had a high progesterone output with relatively low cortisol and PGE production, whereas decidual cells had a high cortisol and PGE production rate. Free arachidonic acid stimulated PGE production in both decidual and chorionic cells. There were no significant differences in either steroid or PGE production among the four groups studied. These data suggest that steroid dehydrogenase activity in choriodecidual cells is not related to the mode of onset of labour and that the increased prostaglandin production in intrauterine tissues associated with parturition is due to enhanced availability of arachidonic acid. 相似文献
15.
Raúl González-García Francisco J Rodríguez-Campo Verónica Escorial-Hernández Mario F Mu?oz-Guerra Jesús Sastre-Pérez Luis Naval-Gías José L Gil-Díez Usandizaga 《Journal of oral and maxillofacial surgery》2006,64(11):1587-1591
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique. 相似文献
16.
Henyse G V Silva Rosangela P Tórtora Maria Lucia F Farias 《Gynecological endocrinology》2005,21(3):174-179
To evaluate the impact of pregnancy on bone, we studied bone turnover at the first (T1) and third (T3) trimester of gestation in 58 adolescents and 28 healthy adolescents who had never been pregnant. Total body (TB) and lumbar spine (LS) bone mineral density (BMD) and body composition were evaluated by dual-energy X-ray absorptiometry in all control patients (C) and after parturition in 28 pregnant patients (G). Paired and unpaired t tests, Mann-Whitney and Pearson correlation tests were used. Bone turnover markers were above the reference range for adult women in more than 80% of the adolescents, with no difference between C and G patients at T1. Increase in urinary N-telopeptide crosslinks of type I collagen and serum bone-specific alkaline phosphatase, markers of bone turnover, was seen during pregnancy ( p < 0.0001). Body composition did not differ between groups, but LS BMD, percentage of expected LS BMD, LS Z-score, percentage of expected TB BMD and TB Z-score were lower in G than C patients ( p < 0.05). TB BMD was positively correlated with LS BMD (r2 = 0.52). The inverse correlations between bone markers and LS BMD suggest that the increased bone turnover during pregnancy probably explains the low bone density after parturition. The impact on future peak bone mass must be studied. 相似文献
17.
18.
19.
G López Casasnovas 《Gaceta sanitaria / S.E.S.P.A.S》1989,3(15):573-580
The following pages try to offer some ways of arguing against pesimism in our health administration culture. In fact, the review of a wide range of feasible reforms of our health system undertaken in this paper gives some clues for a better implementation of the a priori advantages of public health systems. These advantages are not achieved today because of some dysfunctionalities of daily management. To rationalize resources distribution, to evaluate the results, to eliminate unnecessary administrative control, to coordinate responsibility and budgeting centers, to introduce free choice as a response to public demand, and to simulate marketing by private production of public services are elements suggested in this paper to improve public health services management. 相似文献
20.