全文获取类型
收费全文 | 186838篇 |
免费 | 10670篇 |
国内免费 | 492篇 |
专业分类
耳鼻咽喉 | 2494篇 |
儿科学 | 5958篇 |
妇产科学 | 4057篇 |
基础医学 | 25383篇 |
口腔科学 | 8543篇 |
临床医学 | 13570篇 |
内科学 | 42005篇 |
皮肤病学 | 4882篇 |
神经病学 | 15570篇 |
特种医学 | 5778篇 |
外国民族医学 | 26篇 |
外科学 | 23412篇 |
综合类 | 1444篇 |
现状与发展 | 1篇 |
一般理论 | 63篇 |
预防医学 | 18909篇 |
眼科学 | 3389篇 |
药学 | 11268篇 |
中国医学 | 780篇 |
肿瘤学 | 10468篇 |
出版年
2023年 | 989篇 |
2022年 | 2244篇 |
2021年 | 4125篇 |
2020年 | 2770篇 |
2019年 | 3862篇 |
2018年 | 5344篇 |
2017年 | 3985篇 |
2016年 | 3768篇 |
2015年 | 4434篇 |
2014年 | 6094篇 |
2013年 | 7623篇 |
2012年 | 11825篇 |
2011年 | 12465篇 |
2010年 | 6388篇 |
2009年 | 5757篇 |
2008年 | 9739篇 |
2007年 | 10321篇 |
2006年 | 9566篇 |
2005年 | 9850篇 |
2004年 | 9110篇 |
2003年 | 8320篇 |
2002年 | 6330篇 |
2001年 | 5142篇 |
2000年 | 5095篇 |
1999年 | 4519篇 |
1998年 | 1659篇 |
1997年 | 1410篇 |
1996年 | 1372篇 |
1995年 | 1162篇 |
1994年 | 1140篇 |
1993年 | 1041篇 |
1992年 | 2701篇 |
1991年 | 2642篇 |
1990年 | 2399篇 |
1989年 | 2383篇 |
1988年 | 2154篇 |
1987年 | 1999篇 |
1986年 | 1870篇 |
1985年 | 1783篇 |
1984年 | 1298篇 |
1983年 | 1047篇 |
1982年 | 593篇 |
1981年 | 544篇 |
1980年 | 510篇 |
1979年 | 943篇 |
1978年 | 617篇 |
1977年 | 491篇 |
1975年 | 558篇 |
1974年 | 553篇 |
1973年 | 560篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Unusual central chorioretinitis as the first manifestation of early secondary syphilis 总被引:1,自引:0,他引:1
E C de Souza A E Jalkh C L Trempe S Cunha C L Schepens 《American journal of ophthalmology》1988,105(3):271-276
Three young, otherwise healthy patients had a similar picture of unilateral central chorioretinitis associated with severe visual loss. Fluorescein angiography disclosed diffuse leakage under the neurosensory retina in the posterior pole, associated with multifocal areas of staining along the retinal vessels. Systemic examination showed a positive fluorescent treponemal antibody absorption test and a sharp increase in VDRL titers, indicative of active secondary syphilis. The patients responded dramatically to penicillin treatment, with visual recovery and resolution of the fundus lesions. 相似文献
83.
Clinicopathologic correlation of pigmented epiretinal membranes 总被引:1,自引:0,他引:1
G M Cherfan W E Smiddy R G Michels Z de la Cruz C P Wilkinson W R Green 《American journal of ophthalmology》1988,106(5):536-545
We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes. 相似文献
84.
Maria Pia Francescato P. Cok O. Radillo B. de Bernard 《Journal of human nutrition and dietetics》1988,1(5):321-327
A computer-assisted method for the registration of food intakes in real time according to a concise and simple procedure was subjected to a series of controls in order to assess precision. The method employs the 'portion' of a composite dish as unit of measure. The constancy of the portion was tested. The results show that the recipes of the diet of a subject may be stored and utilized in deferred time without loss of precision: data to be recorded in real time are then very limited. The length of period of analysis was also studied. The time of investigation should not be shorter than two weeks to obtain precise information on the feeding habits of an individual subject, whereas for a group of subjects the diary of a single day provides information of sufficient precision. 相似文献
85.
Akosua N.J.A. de Groot Pieter W.J. van Dongen Tom B. Vree Tom K.A.B. Eskes 《European journal of obstetrics, gynecology, and reproductive biology》1995,60(2):101-107
Objective: To study the pharmacodynamic and pharmacokinetic properties of oral and intravenous methylergometrine upon uterine motility during menstruation. Study-design: Intra-uterine pressure was measured in six volunteers with a fluid-filled sponge-tipped catheter during menstruation. Methylergometrine was given orally (0.5 mg) or intravenously (0.2 mg) in a cross-over design. Results: After intravenous administration, a fast increase of the frequency of uterine contractions and basal tone occurred with a decrease of amplitude, lasting at least 30 min. Oral administration had a late and less marked effect on uterine motility. An intravenous dose administered 24 h after an oral dose had no effect on uterine motility. Pharmacokinetic data, such as the maximum plasma concentration (Cmax), the time at which Cmax is reached (tmax) and the half-life of absorption (t1/2abs) also demonstrated large individual variations after oral administration. Conclusion: Oral administration of methylergometrine had an unpredictable and late effect on uterine motility on the menstruating uterus, probably due to an unpredictable bioavailability, in contrast with the fast and predictable effect after intravenous administration. 相似文献
86.
Prospective study of antigenemia,plasma viremia and lymphocytic viremia in HIV-infected hemophiliacs
S. Melón Garcia M. de Oña Navarro C. Rodriguez Pinto M. Fernández Urgellés A. Martinez Gutierrez P. de la Iglesia F. J. Mendez García 《European journal of clinical microbiology & infectious diseases》1995,14(5):400-405
A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51 % of the patients and from PBMC in 87.5 % of the patients. The incidence of HIV isolation in asymptomatic patients (42.8 %) was similar to that found in symptomatic patients (51.4 %). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p<0.05). Plasma viremia was closely associated (p<0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of >500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p<0.05). 相似文献
87.
88.
Traumatic rupture of the thoracic aorta diagnosed by transoesophageal echocardiography. 总被引:2,自引:2,他引:0 下载免费PDF全文
Transoesophageal echocardiography is a safe and rapid means of obtaining anatomical and dynamic information about the descending aorta. It was used to confirm a suspected diagnosis of ruptured descending aorta. 相似文献
89.
L R van Niekerk D P de Klerk M L de Kock A C Schmidt B Stockland 《Suid-Afrikaanse tydskrif vir geneeskunde》1988,73(1):5-8
Percutaneous nephrolithotomy (PCN) enables the urologist to remove upper urinary tract stones through a percutaneous nephrostomy tract. The principal advantages of PCN are the low morbidity, shortened hospital stay and rapid recovery. Percutaneous puncture failed in 5 (11%) of the first 44 patients with upper tract urolithiasis treated by PCN at Tygerberg Hospital. In 35 patients (80%) PCN cleared the kidney of stones but in 4 patients (9%) all stone fragments were not removed during the procedure. If the puncture and dilatation was successful, then 90% of patients were stone-free after PCN. Complications were minimal except for a diabetic who died of septicaemia. PCN is an alternative to open renal surgery in the management of most upper urinary tract stones. The technique is readily mastered by any urologist experienced in endoscopic surgery. 相似文献
90.
Alexandra A. Zaia Ricardo Delia Coletta Oslei P. Almeida Sergio R. P. Line 《European journal of oral sciences》1996,104(5-6):627-629
Atrophy of salivary glands may occur by ductal obstruction caused by calculus, infection or neoplastic processes, or as consequence of systemic diseases and aging. In the present work, we have used histochemical methods to study the expression of elastic and collagen fibers during experimental atrophy of the submandibular gland of mice. Glandular atrophy was accompanied by a rapid increase in collagen deposition in both septal and intralobular regions. The expression of elastic fibers was not significantly altered during atrophy; a discrete increase of elastic fibers was noted only around ductal structures. The results showed that experimental ductal obstruction is a useful in vivo model to study molecular events that take part in the remodeling of the extracellular matrix during atrophy of salivary glands. 相似文献