首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18882篇
  免费   1573篇
  国内免费   37篇
耳鼻咽喉   168篇
儿科学   681篇
妇产科学   455篇
基础医学   2846篇
口腔科学   452篇
临床医学   1766篇
内科学   4137篇
皮肤病学   536篇
神经病学   1599篇
特种医学   798篇
外国民族医学   1篇
外科学   2289篇
综合类   225篇
一般理论   20篇
预防医学   1618篇
眼科学   456篇
药学   1049篇
  1篇
中国医学   10篇
肿瘤学   1385篇
  2021年   216篇
  2019年   204篇
  2018年   254篇
  2017年   178篇
  2016年   215篇
  2015年   237篇
  2014年   328篇
  2013年   491篇
  2012年   722篇
  2011年   758篇
  2010年   413篇
  2009年   417篇
  2008年   735篇
  2007年   743篇
  2006年   735篇
  2005年   765篇
  2004年   663篇
  2003年   665篇
  2002年   671篇
  2001年   638篇
  2000年   725篇
  1999年   577篇
  1998年   264篇
  1997年   224篇
  1996年   202篇
  1995年   229篇
  1994年   199篇
  1993年   200篇
  1992年   503篇
  1991年   497篇
  1990年   449篇
  1989年   480篇
  1988年   434篇
  1987年   458篇
  1986年   441篇
  1985年   407篇
  1984年   373篇
  1983年   255篇
  1982年   177篇
  1981年   180篇
  1980年   211篇
  1979年   275篇
  1978年   231篇
  1977年   184篇
  1976年   191篇
  1975年   184篇
  1974年   216篇
  1973年   202篇
  1972年   170篇
  1971年   166篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Crossed radioimmunoelectrophoresis (CRIE) was used to study the presence of serum IgE against antigenic components of cow milk in 21 selected milk-allergic patients. The amount of each IgE specificity was estimated by a scoring system. The milk-allergic children had mainly IgE against alpha-lactalbumin, beta-lactoglobulin, albumin and immunoglobulin, the four major proteins of bovine whey, as well as IgE against three casein components. A serum pool from 1000 normal adults had IgE against the same whey protein, but in smaller amounts, and no IgE against the casein components. Eight cow milk-based formulae, commonly used for infant feeding, and goat milk were studied by the same method. It was found that six of the milk substitutes did not differ significantly from cow milk in antibody binding, but the two hydrolysed casein products, Nutramigen and Pregestimil, consisted of such small molecules that the rabbit antisera could not precipitate the hydrolysed proteins in the gels on the CRIE plates. It was therefore not possible to study their IgE binding, if any, by this method.  相似文献   
52.
53.
In 1986, an outbreak of Moraxella follicular conjunctivitis occurred in girls attending a Navajo boarding school in New Mexico. We diagnosed 19 cases of culture-proven, and 21 of clinical conjunctivitis based on isolation of Moraxella from conjunctival cultures and the occurrence of symptoms significantly associated with positive culture. Sharing eye makeup was significantly associated with Moraxella-positive conjunctivitis (odds ratio [OR] = 7.2, P = .004) and showed a trend toward significance in those with clinical conjunctivitis (OR = 2.9, P = .09). Eyeliner and eye shadow were implicated (OR = 4.1, P less than .05). We cultured samples of 13 students' makeup; one third of the eyeliners were positive for Moraxella. Nasal carriage of Moraxella was found in 35 (44%) of the 79 female boarders and in 20 (21%) of 97 Navajo patients at two nearby clinics. In a prospective evaluation of the effect of patient education and rifampin therapy on the occurrence of conjunctivitis during an 11-month follow-up period, both types of intervention were successful in significantly reducing the rate of conjunctivitis when compared with that in a control group.  相似文献   
54.
T B Schwartz 《JAMA》1989,262(19):2730-2731
  相似文献   
55.
Physician motivations for nonscientific drug prescribing   总被引:8,自引:0,他引:8  
Although there is increasing concern about inappropriate physician prescribing and how to devise programs to improve drug therapy decisions, little research has been published documenting the reasons for such misprescribing. We analyzed the motivations reported by 141 physicians who were part of a large multi-state randomized controlled trial of 'academic detailing.' The physicians were identified from state Medicaid prescribing records as moderate to high prescribers of cerebral or peripheral vasodilators, propoxyphene, or cephalexin, and were visited by clinical pharmacists serving as outreach educators in a medical school-based prescribing improvement program. Physicians' motivations for their prescribing patterns were discussed in an informal, interactive manner; all responses were recorded in detail by the pharmacists immediately following each visit. Of the 110 responses elicited, the most common reason offered by physicians for use of these medications was patient demand (51 statements, or 46%). Physicians also frequently attributed their prescribing of these drugs to intentional use of placebo effect (24%). An equally common reason was prescribers' assertion that their own clinical experience indicated that these drugs were actually therapies of choice in the conditions presented (26%), despite evidence from the research literature that this was not the case. Such indications included the use of the 'vasodilators' for senile dementia or peripheral vascular disease, cephalexin for viral upper respiratory infections, and propoxyphene instead of acetaminophen or aspirin for mild pain. Greater attention must be paid to physicians' attitudes and motivations concerning suboptimal prescribing if programs are to succeed in replacing these practices with more rational clinical decision-making.  相似文献   
56.
57.
D A Schwartz 《Chest》1989,95(6):1338-1339
A 34-year-old man with chronic myelogenous leukemia developed hemoptysis, pain in the left side of the chest, and a systolic heart murmur eight weeks following an allogeneic bone marrow transplant. His clinical status deteriorated, and he died ten weeks after transplantation. Autopsy revealed unsuspected disseminated aspergillosis, including the unusual finding of Aspergillus pancarditis and pericarditis. Cardiac aspergillosis is a uniformly lethal disease in immunocompromised persons and must be aggressively diagnosed following early symptoms.  相似文献   
58.
The calcium channel-inhibiting drugs diltiazem, verapamil and nitrendipine represent three general classes of organic calcium antagonists. In the present study, the effect of these drugs on calcium currents (ICa++) in rabbit sternomastoid muscle fibers was examined. ICa++ were recorded at room temperature using a vaseline gap voltage clamp. ICa++ measured had similar kinetics to those reported in rat skeletal muscle, were partially blocked by 0.5 mM CdCI2 and could be reduced by substitution of Mg++ for Ca++. Diltiazem reversibly blocked ICa++ in a concentration-dependent manner with the 50% inhibitory concentration (IC50) being 63 microM. Verapamil was slightly more potent with approximately 50% block of ICa++ occurring at 10 microM. In contrast, nitrendipine at concentrations from 1 to 10 microM had no blocking action on ICa++, even after 20 min of exposure. Thus, although Ca++ channels in mammalian skeletal muscle fibers are readily blocked by cadmium, diltiazem and verapamil, these channels appear to be insensitive to the dihydropyridine compound nitrendipine.  相似文献   
59.
Human microsporidial infections.   总被引:1,自引:0,他引:1       下载免费PDF全文
Microsporidia are obligate intracellular spore-forming protozoal parasites belonging to the phylum Microspora. Their host range is extensive, including most invertebrates and all classes of vertebrates. More than 100 microsporidial genera and almost 1,000 species have now been identified. Five genera (Enterocytozoon spp., Encephalitozoon spp., Septata spp., Pleistophora sp., and Nosema spp.) and unclassified microsporidia (referred to by the collective term Microsporidium) have been associated with human disease, which appears to manifest primarily in immunocompromised persons. The clinical manifestations of microsporidiosis are diverse and include intestinal, pulmonary, ocular, muscular, and renal disease. Among persons not infected with human immunodeficiency virus, ten cases of microsporidiosis have been documented. In human immunodeficiency virus-infected patients, on the other hand, over 400 cases of microsporidiosis have been identified, the majority attributed to Enterocytozoon bieneusi, an important cause of chronic diarrhea and wasting. Diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Initial detection of microsporidia by light microscopic examination of tissue sections and of more readily obtainable specimens such as stool, duodenal aspirates, urine, sputum, nasal discharge, bronchoalveolar lavage fluid, and conjunctival smears is now becoming routine practice. Definitive species identification is made by using the specific fluorescein-tagged antibody (immunofluorescence) technique or electron microscopy. Treatment options are limited, but symptomatic improvement of Enterocytozoon bieneusi infection may be achieved with the anthelmintic-antiprotozoal drug albendazole. Preliminary observations suggest that Septata intestinalis and Encephalitozoon infections may be cured with albendazole. Progress is being made with respect to in vitro propagation of microsporidia, which is crucial for developing antimicrosporidial drugs. Furthermore, molecular techniques are being developed for diagnostic purposes, taxonomic classification, and analysis of phylogenetic relationships of microsporidia.  相似文献   
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号