全文获取类型
收费全文 | 178082篇 |
免费 | 9399篇 |
国内免费 | 1038篇 |
专业分类
耳鼻咽喉 | 2000篇 |
儿科学 | 5351篇 |
妇产科学 | 4080篇 |
基础医学 | 24938篇 |
口腔科学 | 5919篇 |
临床医学 | 14869篇 |
内科学 | 41236篇 |
皮肤病学 | 4367篇 |
神经病学 | 16793篇 |
特种医学 | 4932篇 |
外国民族医学 | 7篇 |
外科学 | 18455篇 |
综合类 | 786篇 |
一般理论 | 68篇 |
预防医学 | 17241篇 |
眼科学 | 3033篇 |
药学 | 12381篇 |
中国医学 | 732篇 |
肿瘤学 | 11331篇 |
出版年
2023年 | 1446篇 |
2022年 | 3188篇 |
2021年 | 5666篇 |
2020年 | 3350篇 |
2019年 | 4751篇 |
2018年 | 6930篇 |
2017年 | 4852篇 |
2016年 | 4755篇 |
2015年 | 5188篇 |
2014年 | 6942篇 |
2013年 | 9051篇 |
2012年 | 13677篇 |
2011年 | 14164篇 |
2010年 | 7883篇 |
2009年 | 6736篇 |
2008年 | 11363篇 |
2007年 | 11339篇 |
2006年 | 10511篇 |
2005年 | 10068篇 |
2004年 | 9077篇 |
2003年 | 8236篇 |
2002年 | 7539篇 |
2001年 | 2211篇 |
2000年 | 2119篇 |
1999年 | 2044篇 |
1998年 | 1350篇 |
1997年 | 1021篇 |
1996年 | 890篇 |
1995年 | 763篇 |
1994年 | 703篇 |
1993年 | 612篇 |
1992年 | 971篇 |
1991年 | 766篇 |
1990年 | 742篇 |
1989年 | 652篇 |
1988年 | 601篇 |
1987年 | 581篇 |
1986年 | 544篇 |
1985年 | 446篇 |
1984年 | 384篇 |
1983年 | 333篇 |
1982年 | 280篇 |
1981年 | 221篇 |
1980年 | 230篇 |
1979年 | 256篇 |
1978年 | 243篇 |
1977年 | 208篇 |
1976年 | 192篇 |
1975年 | 194篇 |
1974年 | 203篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Eser Tüfek?i Thomas E Merrill Maria R Pintado John P Beyer William A Brantley 《American journal of orthodontics and dentofacial orthopedics》2004,125(6):733-739
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn). Specimen surfaces were also examined with a scanning electron microscope. Two-way analysis of variance was performed to analyze the data. In teeth without WSL, the volume losses were 0.16 mm(3) for the bur group and 0.10 mm(3) for the disk group; the mean maximum depths were 47.7 microm for the bur group and 54.3 microm for the disk group. In teeth with WSL, the volume losses were 0.06 and 0.17 mm(3), and the mean maximum depths were 35.1 and 48.7 microm for the bur and disk groups, respectively. There were no significant differences in enamel loss between the 2 groups of teeth without WSL (P =.12). However, in teeth with WSL, the burs removed less enamel than the disks (P = 0.006). Scanning electron microscope examination showed that any damage on the enamel surface was usually located in the cervical third of the teeth. On most specimens, even though tooth surfaces appeared resin-free to the naked eye, there were remnants of it. The differences between groups were so small that they might be clinically insignificant. 相似文献
62.
A 59-year-old man developed dystonia and reflex sympathetic dystrophy after receiving high doses of ergotamine for migraine treatment. Ischemia is suggested as the precipitating factor. 相似文献
63.
This study investigates whether tissue recoil or patient intrinsic factors influence the final position of the nipple areola
complex (NAC) after reduction mammoplasty.
The age, pre-operative ptosis, BMI and weight of the tissue resected were recorded as patient intrinsic factors in 37 patients
undergoing reduction mammoplasty. The “spring-back” value was defined as the distance from the sternal notch to a nipple landmark
on the breast meridian with the patient sitting up, minus the same measurement repeated with the patient recumbent to eliminate
the pull of gravity on the breast. Spring back was measured pre-operatively for the nipple and nipple mark then post-operative
for the nipple. The difference in centimeters between the final post-operative distance from the sternal notch to the nipple
and the level intended by the pre-operative nipple mark was termed the “judgment error.” The final position of the post-operative
nipple and the judgment error was compared to the spring-back values and patient intrinsic factors.
Pre-operative ptosis was statistically related to increasing patient BMI and mass of tissue resected per breast. Pre-operative
spring-back values for the nipple increased with increasing ptosis, BMI and decreasing age. Spring-back values were greater
in the lower pole of the breast than in the upper pole. The final position of the nipple was higher than the pre-operative
mark in 65% of cases, lower in 8% and as marked in 27% of cases. The post-operative NAC was, on average, 0.6 cm higher than
planned pre-operatively. The post-operative distance from the sternal notch to the nipple increased with increasing pre-operative
ptosis, mass of breast tissue resected per breast and all three spring-back values. The difference between the level of the
pre-operative mark and the final nipple position showed a weak correlation with post-operative spring-back values.
The parameters of ptosis, BMI, weight of tissue resected per breast and pre-operative nipple spring back reflect body habitus
and breast size. Spring-back values vary between the upper and lower pole of the breast. The final NAC position was higher
than that intended at pre-operative marking in the majority of cases. The surgeon instinctively marks the nipple lower in
patients with greater pre-operative ptosis and in whom a larger resection is anticipated. Judgment error did not relate to
intrinsic factors nor to pre-operative spring-back values; hence, these parameters cannot be applied as predictive tools for
more accurate pre-operative marking of the nipple position. This study suggests that the pre-operative nipple mark should
be placed, with the patient sitting up, at least 23 cm from the sternal notch and 0.6 cm lower than the final position estimated
using the inframammary crease as a landmark.
An invited commentary on this paper is available at . 相似文献
64.
Hyper-IgM syndrome with CHARGE association 总被引:1,自引:0,他引:1
Pilar Bahillo Teresa Cantero Pilar Solís Paz Aragón Samuel Gómez Rosario Cambronero 《Pediatric allergy and immunology》2003,14(6):487-489
A girl with coloboma of the iris, sensorineural deafness, growth delay, distinctive face, and cranial nerve dysfunction was diagnosed of CHARGE association in the first year of life. She presented with repeated otitis. At 3 yr of age, the patient suffered a septicemia ( Streptococcus pneumoniae , Corynebacterium sp.). The immunoglobulin G (IgG) and IgA serum levels were decreased, IgM increased and cellular immunity parameters were normal, supporting the diagnosis of hyper-IgM (HIM) syndrome. The sequence of CD40 ligand and cytidine deaminase genes were normal. From then on, she was receiving immunoglobulin intravenously with an excellent outcome . Here, we report the first case of CHARGE association and HIM syndrome in the same patient. Although the cause could not be identified, a non-random link is likely. 相似文献
65.
66.
Rosangela Saga Kamikawa Marlene Fenyo Pereira Angela Fernandes Maria Inês Meurer 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,101(3):374-378
OBJECTIVE: To determine the location in soft tissues of the calcifications, similar to calcified carotid atheromas, that can be observed radiographically in the cervical region in panoramic radiographs. STUDY DESIGN: In each anatomic cadaver specimen preserved in formol, consisting of the head and neck, radiopaque spheres (made from gutta-percha) were positioned in anatomic structures of the cervical region that can be sites of calcification. For each anatomic structure marked in this way, panoramic radiography was performed, consisting of 17 radiographs. The images obtained were analyzed by 24 examiners who indicated which radiographs, in their opinion, presented the radiopaque reference projected in the region of bifurcation of the carotid artery. Analysis of 2 proportions from agreement and disagreement was used to determine radiopacities that could be confused in panoramic radiographs with calcified atheromas in the carotid artery. RESULTS: The results showed that 75% (18) of the examiners correctly indicated the reference in the bifurcation of the carotid artery and 79.2% (19) indicated a triticeous cartilage as calcified atheroma of the carotid artery. CONCLUSIONS: Calcified atheromas of the carotid artery are not the only features that can produce radiopaque images lateral to the panoramic radiograph; the presence of calcification in the triticeous cartilage also can induce an erroneous diagnosis of calcified carotid atheroma. 相似文献
67.
Alberto Castilla M.D. Joan Camps-Bansell M.D. Maria-Pilar Civeira M.D. Jesús Prieto M.D. 《The American journal of gastroenterology》1993,88(2):233-239
Forty patients with chronic hepatitis C (CHC) were included in an open randomized controlled trial of lymphoblastoid α-interferon (L-IFN) versus no treatment. Twenty patients entered each group, and features of therapy and control cases were similar. L-IFN was given in low doses (1.5-4.5 megaunits) for 1 yr. In 16 of 20 patients treated with L-IFN (80%), but in only one of 20 nontreated cases (0.5%; p < 0.001), aminotransferase activities became normal. In four patients there was a reactivation of the disease during treatment after 4, 5, 6, and 8 months with normal aminotransferase levels. A posttherapy reactivation of hepatitis was observed in four additional cases after 1, 1, 1, and 3 months of follow-up. The other eight patients (40%) continued with normal aminotransferase levels for 1.52 ± 0.74 (range, 1-2.1) yr after IFN doses were discontinued. In all treated patients except two nonresponders, but in only one of 20 nontreated cases ( p < 0.001), Knodell's histological activity index decreased. Procollagen type III aminoterminal peptide levels did not change significantly in nontreated and nonresponder patients, diminished slightly in patients with a transient response, and normalized in cases with a long-standing response, suggesting that this serum test may be a reliable marker for monitoring response to IFIN therapy in patients with CHC. Finally, L-IFN treatment induced significant increments in CD4/CD8 index, phytohemagglutinin-induced blastogenesis, and natural killer activity. This study shows that L-IFN diminish inflammatory and fibrogenic activity in most patients with CHC. In 40% of patients treated in this trial, a long-standing remission of the disease was observed. 相似文献
68.
J Canet J Vallés P Vila F Vidal 《Revista espa?ola de anestesiología y reanimación》1990,37(6):366-369
Patients with morbid obesity present a series of functional and morphologic alterations and require a careful planning for anesthetic management. We report a case of a woman weighing 260 kg who was operated on twice for the treatment of her base condition. In the first operation, general anesthesia was carried out and in the second one, epidural anesthesia was conducted. Main complications included hypoxemia and hypercapnia which persisted during the first week after operation carried out under general anesthesia. 相似文献
69.
Dr. J. Tajti MD PhD ; Dr. K. Sas MD ; Dr. D. Szok MD ; Dr. E. Vörös MD ; Dr. L. Vécsei MD DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache. 相似文献
70.