全文获取类型
收费全文 | 25652篇 |
免费 | 1839篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 312篇 |
儿科学 | 962篇 |
妇产科学 | 631篇 |
基础医学 | 3364篇 |
口腔科学 | 1055篇 |
临床医学 | 2774篇 |
内科学 | 5044篇 |
皮肤病学 | 408篇 |
神经病学 | 2059篇 |
特种医学 | 939篇 |
外科学 | 3656篇 |
综合类 | 385篇 |
一般理论 | 43篇 |
预防医学 | 2412篇 |
眼科学 | 374篇 |
药学 | 1571篇 |
1篇 | |
中国医学 | 29篇 |
肿瘤学 | 1518篇 |
出版年
2022年 | 201篇 |
2021年 | 434篇 |
2020年 | 311篇 |
2019年 | 459篇 |
2018年 | 544篇 |
2017年 | 408篇 |
2016年 | 446篇 |
2015年 | 539篇 |
2014年 | 712篇 |
2013年 | 930篇 |
2012年 | 1308篇 |
2011年 | 1467篇 |
2010年 | 796篇 |
2009年 | 674篇 |
2008年 | 1234篇 |
2007年 | 1352篇 |
2006年 | 1240篇 |
2005年 | 1217篇 |
2004年 | 1076篇 |
2003年 | 1038篇 |
2002年 | 902篇 |
2001年 | 699篇 |
2000年 | 696篇 |
1999年 | 573篇 |
1998年 | 257篇 |
1997年 | 212篇 |
1996年 | 214篇 |
1995年 | 228篇 |
1994年 | 204篇 |
1993年 | 184篇 |
1992年 | 497篇 |
1991年 | 488篇 |
1990年 | 461篇 |
1989年 | 448篇 |
1988年 | 404篇 |
1987年 | 371篇 |
1986年 | 323篇 |
1985年 | 399篇 |
1984年 | 301篇 |
1983年 | 270篇 |
1982年 | 163篇 |
1979年 | 227篇 |
1978年 | 188篇 |
1977年 | 156篇 |
1976年 | 152篇 |
1975年 | 164篇 |
1974年 | 169篇 |
1973年 | 208篇 |
1972年 | 165篇 |
1971年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
We describe two infants with heterotopic skeletal muscle in the leptomeninges of the posterior fossa. In one case, the heterotopic muscle was accompanied by adipose tissue. Leptomeningeal rhabdomyomatosis may be more common than is apparent from the literature, since these lesions are missed if the meninges become denuded from the brain stem at autopsy or brain cutting. 相似文献
132.
Cell-mediated and humoral immune responses induced by scarification vaccination of human volunteers with a new lot of the live vaccine strain of Francisella tularensis. 下载免费PDF全文
D M Waag A Galloway G Sandstrom C R Bolt M J England G O Nelson J C Williams 《Journal of clinical microbiology》1992,30(9):2256-2264
Tularemia is a disease caused by the facultative intracellular bacterium Francisella tularensis. We evaluated a new lot of live F. tularensis vaccine for its immunogenicity in human volunteers. Scarification vaccination induced humoral and cell-mediated immune responses. Indications of a positive immune response after vaccination included an increase in specific antibody levels, which were measured by enzyme-linked immunosorbent and immunoblot assays, and the ability of peripheral blood lymphocytes to respond to whole F. tularensis bacteria as recall antigens. Vaccination caused a significant rise (P less than 0.05) in immunoglobulin A (IgA), IgG, and IgM titers. Lymphocyte stimulation indices were significantly increased (P less than 0.01) in vaccinees 14 days after vaccination. These data verify that this new lot of live F. tularensis vaccine is immunogenic. 相似文献
133.
The physiological role of the amphibian paraphysis was studied by removing the paraphysis from bullfrog tadpoles (Rana catesbeiana) and observing change in frog weight, bone development, and parathyroid glands 22 months later. Development was similar in control and paraphysectomized frogs until 6 months when the experimental frogs began to show greater weight gain which persisted for the remaining 16 months. At the time of sacrifice (22 months after paraphysectomy), the parathyroid glands of the experimental frogs were enlarged with a tenfold increase in wet weight and a sevenfold increase in dry weight. The glands from experimental frogs had numerous cysts filled with eosinophilic staining material; histologically the cell nuclei were rounded and the cytoplasm was vesiculated. At the time of sacrifice the experimental frogs had knoblike deformities along the shafts of the long bones. These deformities were due to callus formation around spontaneous bone fractures as revealed by X-rays of the tibia-fibulas and femurs. The dry weight was greater but calcium content less in femurs from experimental frogs. These findings indicate the paraphysis plays a role in calcium metabolism, possibly by producing a factor necessary for calcium action on cells. 相似文献
134.
Diez-Ewald M Campos G Rivero F Alvarez L Torres E Arocha-Piñango CL Ryder E Arteaga-Vizcaíno M Vizcaíno G Fernández N 《Investigación clínica》2003,44(1):21-30
The purpose of the present work was to determine the plasma concentrations of fibrinogen and Von Willebrand Factor (VWF) as well as platelet aggregation, in an apparently healthy population of 306 men and 41 women, 33 to 65 years of age, workers of the national oil industry (PDVSA, Maracaibo), as a base investigation in a 5-year prospective national collaborative study. The participants were previously subjected to a thorough clinical examination with cardiovascular evaluation and laboratory tests. Clottable fibrinogen and VWF concentrations were determined in platelet poor plasma, the last one by immunoclectrophoresis, and a multimeric analysis of VWF was performed on those plasmas with concentrations higher than 150 U/dL by SDS agarose electrophoresis, followed by cellulose membrane transference. Platelet aggregation was studied in platelet rich plasma with no addition of stimulants and after collagen and ristocetin were added. Forty per cent of men and 65.8% of women, showed fibrinogen concentrations above 300 mg/dL (p < 0.01) and 12.2% of men and 15.4% of women had VWF values higher than 150 U/dL, with normal multimeric distribution. Fourteen individuals presented spontancous platelet aggregation and increased aggregation in 12 and 13 of them, after induction with collagen and ristocetin respectively. Comparing these findings with those of previous collaborative studies from other countries, the present results could mean that an important proportion of the population here studied, could be at risk for a future coronary event; however, as these are the base findings in Maracaibo, the significance of our results will be better evaluated at the end of the five year study. 相似文献
135.
Parotid gland enlargement and xerostomia associated with labial sialadenitis in HIV-infected patients 总被引:5,自引:0,他引:5
M Schi?dt D Greenspan T E Daniels J Nelson P J Leggott D W Wara J S Greenspan 《Journal of autoimmunity》1989,2(4):415-425
Infection with human immunodeficiency virus (HIV) may be associated with enlargement of the major salivary glands or symptoms of dry mouth. We term this condition HIV-associated salivary gland disease (HIV-SGD). In this report we describe 12 patients with HIV-SGD. Nine patients (one child, eight adults) had enlargement of the parotid glands, and three had xerostomia alone. Symptoms of dry mouth, dry eyes or arthralgia occurred in 11, five and five patients, respectively. Salivary flow rates were normal or slightly reduced in seven patients and severely reduced in five. Labial salivary gland (LSG) biopsy specimens from patients contained lymphocytic infiltrates in focal and other patterns, whereas specimens from three HIV-infected patients without salivary gland symptoms did not. The inflammatory infiltrates in LSG specimens showed a preponderance of T8-positive cells and a tissue T4/T8 average ratio of 0.66. The mean T4/T8 ratio of peripheral blood lymphocytes was 0.4. Serum antinuclear antibodies were present in one patient, but rheumatoid factor, SS-A, and SS-B antibodies were absent in all. Search for Epstein-Barr virus and cytomegalovirus in the LSG tissue of the six patients tested did not reveal evidence of antigens or DNA. HIV-SGD patients show a number of similarities to and differences from patients with Sj?gren's syndrome (SS). The similarities include the oral and salivary features, histopathology and possibly changes in other organs. The differences include the lower salivary gland T4/T8 ratio and the absence of autoantibodies in serum. The causes of HIV-SGD as well as of Sj?gren's syndrome are unknown. 相似文献
136.
P N Nelson S M Fletcher D MacDonald D M Goodall R Jefferis 《Journal of immunological methods》1991,138(1):57-64
Three monoclonal antibodies raised against a purified human IgG3 paraprotein were found to exhibit a restriction profile for IgG3/G3m(u) and pan-IgG specificity which was dependent on the assay system. When adapted to an IgG3 subclass capture ELISA, all three McAbs discriminated between paraproteins expressing G3m(u) and antithetical markers G3m(st). One of the antibodies (PNF69C) was selected and conditions were optimised for Gm typing purposes. Using this system G3m(u) could be detected on captured IgG3 derived from human sera. This system may prove useful in the elucidation of Gm allotype profiles. 相似文献
137.
138.
Differential immunoglobulin G subclass antibody titers to respiratory syncytial virus F and G glycoproteins in adults 总被引:1,自引:0,他引:1 下载免费PDF全文
D K Wagner D L Nelson E E Walsh C B Reimer F W Henderson B R Murphy 《Journal of clinical microbiology》1987,25(4):748-750
Two respiratory syncytial virus glycoproteins, F and G, which differ substantially in the amount of glycosylation were used as antigens in an enzyme-linked immunosorbent assay to determine immunoglobulin G (IgG) subclass titers in 30 experimentally infected healthy adults. The titers of antibodies to the F glycoprotein achieved in postinfection sera were highest in the IgG1 subclass, whereas those to the G glycoprotein were highest and comparable in the IgG1 and IgG2 subclasses. The high IgG2 response to the G glycoprotein suggests that it is seen by the immune system as a polysaccharide antigen, a hypothesis consistent with its large carbohydrate content. 相似文献
139.
J D Edinger W M Nelson K G Bailey J Wallace R Lyman 《Journal of clinical psychology》1979,35(4):807-814
Determined the efficacy of profile analysis with a prison population (63 white, 63 black) of the Petersburg Federal Correctional Institution as Ss. By use of Veldman's Hierarchical Profile Analysis, five distinctive WAIS profile types were derived empirically for each racial group. Analyses of covariance that controlled for full-scale IQ differences revealed significant differences among the profile types within each race in terms of Stanford Achievement Test scores and MMPI T-scores. Further, partial correlations indepepdent of full-scale IQ revealed significant relationships between some of the profile types and the commission of rule infractions while incarcerated. These findings are interpreted as supportive of profile analysis with inmate populations. However, it is suggested that further research be effected to cross-validate these findings. 相似文献
140.
D S Nelson 《Clinical and experimental immunology》1981,45(2):225-233