全文获取类型
收费全文 | 18979篇 |
免费 | 1251篇 |
国内免费 | 88篇 |
专业分类
耳鼻咽喉 | 216篇 |
儿科学 | 429篇 |
妇产科学 | 349篇 |
基础医学 | 2614篇 |
口腔科学 | 331篇 |
临床医学 | 1638篇 |
内科学 | 4891篇 |
皮肤病学 | 416篇 |
神经病学 | 1620篇 |
特种医学 | 681篇 |
外科学 | 2667篇 |
综合类 | 248篇 |
一般理论 | 8篇 |
预防医学 | 1398篇 |
眼科学 | 414篇 |
药学 | 1127篇 |
中国医学 | 80篇 |
肿瘤学 | 1191篇 |
出版年
2023年 | 133篇 |
2022年 | 330篇 |
2021年 | 547篇 |
2020年 | 310篇 |
2019年 | 450篇 |
2018年 | 518篇 |
2017年 | 348篇 |
2016年 | 366篇 |
2015年 | 453篇 |
2014年 | 625篇 |
2013年 | 847篇 |
2012年 | 1336篇 |
2011年 | 1351篇 |
2010年 | 789篇 |
2009年 | 682篇 |
2008年 | 1127篇 |
2007年 | 1203篇 |
2006年 | 1183篇 |
2005年 | 1108篇 |
2004年 | 1009篇 |
2003年 | 961篇 |
2002年 | 957篇 |
2001年 | 136篇 |
2000年 | 117篇 |
1999年 | 163篇 |
1998年 | 220篇 |
1997年 | 180篇 |
1996年 | 182篇 |
1995年 | 131篇 |
1994年 | 126篇 |
1993年 | 106篇 |
1992年 | 102篇 |
1991年 | 103篇 |
1990年 | 91篇 |
1989年 | 79篇 |
1988年 | 85篇 |
1987年 | 90篇 |
1986年 | 74篇 |
1985年 | 96篇 |
1984年 | 99篇 |
1983年 | 94篇 |
1982年 | 115篇 |
1981年 | 126篇 |
1980年 | 110篇 |
1979年 | 65篇 |
1978年 | 76篇 |
1977年 | 90篇 |
1976年 | 65篇 |
1975年 | 51篇 |
1974年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
21.
Josh W. McDonald Victor L. Roggli William D. Bradford 《Fetal and pediatric pathology》1994,14(3):505-511
We report a unique case of coexistingexogenous lipoid pneumonia, endogenous lipoid pneumonia (EU), and pulmonary alveolar proteinosis (PAP) in a 5-year-old patient with severe neurodevelop mental disease. The patient presented with gastroesophageal reflux and presumed chronic lung disease resulting from recurrent aspiration pneumonias and succumbed to respiratory failure. The autopsy showed lipid-laden macrophages and periodic acid-SchiJf9ositive granular matm'al i n alveolar spaces and multilamellated structures within both alveolar macrophages and extracellular debris.
These findings were similar to those in previous reports of coexisting E I P and PAP in the setting of gastroesophageal refux [I] . However, the present case diJfered by the presence of scattered large osmiophilic extracellular lipid vacuob. Besides strengthening the association between EIP and PAP and their relationship to gastroesophageal refux, this case suggests that t h q may arise together with exogenous lipoid pneumonia, through related mechanisms, in the setting of neurodevelopmental disease. 相似文献
These findings were similar to those in previous reports of coexisting E I P and PAP in the setting of gastroesophageal refux [I] . However, the present case diJfered by the presence of scattered large osmiophilic extracellular lipid vacuob. Besides strengthening the association between EIP and PAP and their relationship to gastroesophageal refux, this case suggests that t h q may arise together with exogenous lipoid pneumonia, through related mechanisms, in the setting of neurodevelopmental disease. 相似文献
22.
Reports of accessory soleus muscle are rare, perhaps as a result of it often remaining unrecognized. It presents as a swelling behind the ankle and may be mistaken for a tumour or inflammatory lesion, as occurred in the first of a series of three cases. The other two were incidental findings, one in a 30 year old man with an open tibial fracture and the other in a 9 month old child with a club foot. Patients present with either pain or a diagnostic problem. When large, it may make wearing of footwear difficult. Computerized tomography with electromyography enables confirmation of the diagnosis. Pain is relieved by epimysiotomy and when encountered incidentally during surgery, incision of the epimysium is all that is needed. Excision of the muscle may be considered only if wearing of footwear is difficult. The significance of its presence in a case of club foot is unknown. Disinsertion of its insertion was all that was required to obtain surgical correction of the deformity in the present case. Awareness of the condition will prevent unnecessary surgery in asymptomatic cases. 相似文献
23.
Pedro Magno José Loureiro Alexandre Marques Pedro Farto E Abreu Machado Candido Paulo Leal Victor M Gil 《Revista portuguesa de cardiologia》2007,26(10):1033-1042
Ischemic stroke occurs in 0.2-0.4% of patients undergoing left heart catheterization, and is responsible for 5-10% of the mortality associated with the procedure. The main predisposing factors for this complication are female gender, complex atherosclerotic plaques in the ascending aorta, and peripheral arterial disease. The possibility of timely intervention with reperfusion therapy supports close clinical monitoring during the immediate post-catheterization period. The cardiologist should be familiar with the various types of stroke reperfusion therapy and its indications according to the time interval between catheterization and the stroke. The decision should be discussed with neurology and neuroradiology. 相似文献
24.
Richard B. Dewey Jr Surendra D. Rao Stephanie L. Holmburg Ronald G. Victor 《European journal of neurology》1998,5(6):593-599
Eight patients with parkinsonism who developed severe orthostatic sypotension, were treated with oral ergotamine/caffeine. Significant long-term improvement in standing systolic blood pressure and symptoms of syncope and light-headedness were observed in four of these patients. One patient in whom the drug was effective discontinued it because of nausea. Another lost benefit after 2 weeks of sucessful therapy. Significant supine systolic hypertension occureed in only one patient, which was easily managed by nifedipine given at night. Symptoms or signs of ergotism were not observed. Oral ergotamine/caffeine should be considered as a cost-effective teratment for refactory orthostatic hypotension in carefully selected patients with parkinsonism. 相似文献
25.
26.
27.
Microneurographic measurements of muscle sympathetic nerve activity (SNA) have suggested that, during static exercise, central command is much less important than skeletal muscle afferents in causing sympathetic neural activation. The possibility remains, however, that the sympathetic discharge produced by central command is targeted mainly to tissues other than skeletal muscle. To examine this possibility, we recorded SNA with microelectrodes placed selectively in skin, as well as in muscle, nerve fascicles of the peroneal nerve during static handgrip maneuvers designed to separate the effects of central command from those of muscle afferents. To study the relative effects of cutaneous sympathetic activation on sudomotor versus vasomotor function, we simultaneously estimated changes in skin blood flow (laser Doppler velocimetry) and in sudomotor (electrodermal) activation in the region of skin innervated by the impaled nerve fascicle. Two minutes of static handgrip at 10%, 20%, and 30% of maximal voluntary contraction caused large and intensity-dependent increases in skin SNA. These increases in SNA immediately preceded the onset of muscle tension, accelerated progressively during sustained handgrip, and resolved promptly with the cessation of motor effort. The handgrip-induced increases in skin SNA were not maintained when handgrip was followed by arrest of the forearm circulation, a maneuver that maintains the stimulation of chemically sensitive muscle afferents while eliminating the influences of central command and mechanically sensitive muscle afferents. During normothermia, static handgrip at 30% maximal voluntary contraction caused sustained increases in skin SNA (+400 +/- 83%, mean +/- SEM, p less than 0.05) and in electrodermal activity (+276 +/- 56%, p less than 0.05) but only transient increases in estimated skin vascular resistance (+11 +/- 2%, p less than 0.05). When skin temperature was increased or decreased to a new stable baseline level, subsequent increases in skin SNA during handgrip were accompanied by sustained but directionally opposite changes in estimated skin vascular resistance, with exercise-induced vasodilation during hyperthermia but exercise-induced vasoconstriction during hypothermia. From these observations, we conclude the following: 1) static exercise markedly increases sympathetic outflow to skin as well as to skeletal muscle; 2) the increases in skin SNA, unlike muscle SNA, appear to be caused mainly by central command rather than by muscle afferent reflexes; and 3) this cutaneous sympathetic activation appears to be targeted both to sweat glands and to vascular smooth muscle, with the relative targeting being temperature dependent.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
28.
Victor Y. Fujimoto MD J.Heath Miller MD Nancy A. Klein MD Michael R. Soules MD 《American journal of obstetrics and gynecology》1997,177(6):1419-1425
OBJECTIVE: Our aim was to evaluate the clinical course and management of congenital cervical atresia. STUDY DESIGN: This retrospective analysis included 7 patients referred to our clinic and a review of the medical literature. RESULTS: Including this case series, 58 cases of congenital cervical atresia have been reported in the literature. Forty-eight percent of patients had isolated congenital cervical atresia with a normal vagina whereas the remainder had either complete or partial vaginal atresia (“shortened blind vaginal pouches”). Surgical management has included abdominal hysterectomy or uterovaginal cannulation with or without vaginoplasty. In 59% of patients who underwent uterovaginal canalization procedures (23/39), normal menstrual bleeding was achieved. Four of these patients subsequently became pregnant and were delivered at term. CONCLUSION: Surgical canalization in selected patients with congenital cervical atresia can be successfully performed to provide patients an opportunity for conservative management, resulting in normal menstrual bleeding, resolution of cyclic pelvic pain, and some potential (albeit limited) for fertility.(Am J Obstet Gynecol 1997;177:25) 相似文献
29.
Dr. Hershel Jick M.D. Dr. Laura E. Derby D.Sc. Dr. Victor Gurewich M.D. Mr. Catherine Vasilakis M.P.H. 《Pharmacotherapy》1996,16(3):321-326
We conducted a case-control study based on computer-recorded information accrued in the United Kingdom General Practice Research Database to assess and compare the relation between different antihypertensive drug therapies and myocardial infarction in patients with no known clinical or laboratory risk factors for myocardial infarction other than hypertension. Cases were treated hypertensive patients with no other known risk factors who developed a first acute myocardial infarction between January 1, 1993, and October 31, 1994. They were ascertained from a review of the clinical record together with a questionnaire filled out by the attending general practitioner. Controls were matched to each case for age, sex, general practice, and index date. Antihypertensive therapy was derived from the computerized patient record. The study consisted of 210 cases and 793 controls. Compared with users of β-blockers alone, the adjusted relative risk (RR) estimates for all other treatment regimens were close to 1.0. A comparison of users of calcium channel blockers alone with users of β-blockers alone yielded a RR estimate of 0.9 (95% CI 0.5, 1.7). We conclude that the risk of acute myocardial infarction in otherwise healthy, treated hypertensive patients is not materially associated with the particular drug they receive. 相似文献
30.
Victor L. Roggli Philip C. Pratt Arnold R. Brody 《American journal of industrial medicine》1993,23(4):605-614
Although the association between asbestos exposure and malignant mesothelioma is indisputable, controversy continues regarding the relative contribution of the various types of asbestos fibers to the development of mesothelioma. We examined the types of asbestos fibers recovered from lung parenchyma in more than 90 cases of malignant mesothelioma from the United States, using an analytical scanning electron microscope. Almost half of the patients were former asbestos insulators or shipyard workers. The fibers were recovered from lung tissues obtained at autopsy or surgical resection by means of a sodium hypochlorite digestion procedure. Amosite absestos was identified in 81% of the cases and accounted for 58% of all fibers 5 μm or greater in length. Tremolite/actinolite/anthophyllite were identified in 55% of the cases and accounted for 10% of all fiber types. Chrysotile was identified in 21% of the cases and accounted for 3% of fibers exceeding 5 μm in length. Crocidolite was found in 16% of the cases and accounted for 3% of fibers exceeding 5 μm in length. Nonasbestos mineral fibers (commonly found in the lungs of the general population) were observed in 71% of the cases and accounted for 25% of all fibers 5 μm or greater in length. The findings in this study are at odds with the assertion that crocidolite asbestos is responsible for most mesotheliomas in the United States. © 1993 Wiley-Liss, Inc. 相似文献