全文获取类型
收费全文 | 1335791篇 |
免费 | 94291篇 |
国内免费 | 2908篇 |
专业分类
耳鼻咽喉 | 19713篇 |
儿科学 | 40225篇 |
妇产科学 | 38659篇 |
基础医学 | 187200篇 |
口腔科学 | 39817篇 |
临床医学 | 112614篇 |
内科学 | 262361篇 |
皮肤病学 | 30205篇 |
神经病学 | 106358篇 |
特种医学 | 53665篇 |
外国民族医学 | 435篇 |
外科学 | 208206篇 |
综合类 | 31044篇 |
现状与发展 | 6篇 |
一般理论 | 436篇 |
预防医学 | 92030篇 |
眼科学 | 31357篇 |
药学 | 100053篇 |
4篇 | |
中国医学 | 2988篇 |
肿瘤学 | 75614篇 |
出版年
2018年 | 11737篇 |
2015年 | 11871篇 |
2014年 | 16683篇 |
2013年 | 25237篇 |
2012年 | 32993篇 |
2011年 | 34858篇 |
2010年 | 20727篇 |
2009年 | 20224篇 |
2008年 | 33569篇 |
2007年 | 36674篇 |
2006年 | 37248篇 |
2005年 | 36003篇 |
2004年 | 35080篇 |
2003年 | 34057篇 |
2002年 | 33584篇 |
2001年 | 63613篇 |
2000年 | 65322篇 |
1999年 | 55386篇 |
1998年 | 14650篇 |
1997年 | 13458篇 |
1996年 | 12937篇 |
1995年 | 12221篇 |
1994年 | 11467篇 |
1992年 | 42761篇 |
1991年 | 41280篇 |
1990年 | 40553篇 |
1989年 | 39550篇 |
1988年 | 36963篇 |
1987年 | 36408篇 |
1986年 | 34899篇 |
1985年 | 33101篇 |
1984年 | 24822篇 |
1983年 | 21052篇 |
1982年 | 12664篇 |
1981年 | 11568篇 |
1980年 | 10772篇 |
1979年 | 23923篇 |
1978年 | 17068篇 |
1977年 | 14834篇 |
1976年 | 13386篇 |
1975年 | 15267篇 |
1974年 | 18080篇 |
1973年 | 17560篇 |
1972年 | 16810篇 |
1971年 | 15717篇 |
1970年 | 14914篇 |
1969年 | 14346篇 |
1968年 | 13460篇 |
1967年 | 12015篇 |
1966年 | 11258篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
121.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy. 相似文献
122.
Premalignant lesions and nonsquamous malignancy of the penis and carcinoma of the scrotum. 总被引:2,自引:0,他引:2
P F Schellhammer G H Jordan E L Robey J T Spaulding 《The Urologic clinics of North America》1992,19(1):131-142
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma. 相似文献
123.
A case-control study of squamous cell carcinoma of the upper aerodigestive tract conducted in Heidelberg and Giessen (FRG) provided information on occupational factors in 200 patients and 800 controls (adjusted to sex, age and area of living; 4:1 matched design). The number of subjects exposed to wood dusts, organic chemicals, coal products or to cement was significantly elevated in the tumour group. An increased risk for head and neck cancer was observed after exposition to wood dust (RR = 2,2), organic compounds (RR = 2,4), coal products (RR = 2,7) and especially to cement (RR = 4,4). The cancer risk due to cement exposition showed a positive correlation to the duration of exposition and remained significantly elevated after adjustment for alcohol and tobacco consumption. 相似文献
124.
J H Kranzler 《Journal of clinical psychology》1991,47(5):691-697
Results of an hierarchical factor analysis with university students (N = 101) do not support the construct validity of the Multidimensional Aptitude Battery (MAB). Although the MAB Full Scale IQ seems to be a valid measure of general mental ability, the construct validity of the Verbal and Performance scale IQs is not supported. Therefore, the Verbal and Performance IQs should be interpreted with caution, if at all. In addition, re-analysis of previous investigations of the MAB underscores the importance of ascertaining the reading level of subjects prior to the administration of the MAB. Marginal reading proficiency, especially on a timed paper-and-pencil test such as the MAB, will confound results. 相似文献
125.
126.
Analysis of accident logs in child day care centers indicates that biting is common, especially among toddlers 13 to 30 months of age. Children of this age often lack appropriate verbal skills and resort to aggressive means to achieve their goals. Still awkward in gross-motor skills, toddlers can also suffer self-bites following accidental falls. According to medical reports, human bites sometimes are more virulent than animal bites and can cause severe trauma. Although the AIDS virus has been cultured from saliva, transmission from saliva alone has not been documented. Bite injuries in day care, however, usually are minor and can be treated by washing, applying cold compresses, and comforting the child. Suggested methods to diminish the frequency of biting in day care include physical changes within the room, behavior modification, and other classroom management techniques. 相似文献
127.
128.
Hitoshi Ogino Nongchana Klangsuk Wu Jin Christopher T. Bowles Magdi H. Yacoub 《Artificial organs》1995,19(6):525-534
Abstract: The dependence of transient pressure characteristics of a ventricular assist device (VAD) on the compliance of its housing and cannulas was investigated in a mock circulation. The peak rate of change of pressure ( dP/dt max ) values was greater in the cannulas than other compartments and was associated with valve closure-induced pressure oscillations. When cannula compliance was increased from 0.0057 to 0.0129 cm3 /mm Hg, these values decreased by ˜20%, and outflow cannula pressure oscillation frequency decreased from 17.5 Hz by 35%. This trend was also apparent in the inflow. A VAD housing compliance increase from 0.0162 to 0.0483 cm3 /mm Hg caused a dP/dt max decrease of 30% in both the blood chamber and the outflow cannula. The effect of this change on the inflow was weaker implying that housing absorbs the energy associated with outflow deceleration more effectively than the inflow. These findings suggest that increasing VAD housing and cannulas compliance can improve hydrodynamic performance. 相似文献
129.
Development of an auxotrophic oral live Shigella flexneri vaccine 总被引:11,自引:0,他引:11
An oral live attenuated Shigella flexneri vaccine candidate strain was constructed by making it auxotrophic and dependent on aromatic metabolites not available in mammalian tissues. An aroD gene of Escherichia coli K12 strain NK 5131, inactivated by insertion in it of the Tn 10 transposon, was transduced using phage P1 into a virulent S. flexneri serotype Y strain (Sfl 1) isolated from a patient with bacillary dysentery. One of the transductant strains Sfl 114 was found to invade HeLa cells in vitro, to cause plaque formation in HeLa monolayers (i.e. maintain intracellular multiplication in vitro), but to be unable to cause keratoconjunctivitis in guinea-pig eyes. When the strain was fed to Macacca fascicularis monkeys it was well tolerated, excreted for 1-4 days, and found to elicit a local intestinal sIgA and serum IgA, IgM and IgG responses. Monkeys challenged with 100 ID50 dose (1 X 10(11) bacteria) of the virulent parent Sfl 1 strain were completely protected from development of diarrhoea. Coloscopy of the monkeys and the sampling of intestinal biopsies showed that the vaccine protected against the surface epithelial erosions and ulcerations seen in unimmunized monkeys. Killing of invading virulent shigellae apparently took place intracellularly in the mucosa suggesting that cellular immune mechanisms played a role in the elicited host defence. The constructed S. flexneri Sfl 114 strain has the properties of a promising shigella vaccine and will next be the subject of studies with human volunteers. 相似文献
130.
To study the effect of alcohol on glucose and insulin metabolism,a simultaneous infusion of glucose and insulin was given for150 min to healthy volunteers, once during alcohol and onceduring calorie-free gingerale (control) ingestion. During alcoholintake, the average steady-state (between 100 and 150 min) glucoseof 5.44±0.39 mmol/1. and the average steady-state insulinof 6.3±1.1 ng/ml were significantly higher than those(4.0±0.39 mmol/1. of glucose and 4.4±0.6 ng/mlof insulin) observed during the control state. Despite the highersteady-state insulin concentrations, the glucose metabolismwas significantly less during alcohol ingestion. These findingssuggest alcohol-induced impairment in glucose metabolism iscaused by a decreased tissue sensitivity to insulin. 相似文献