全文获取类型
收费全文 | 3496篇 |
免费 | 277篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 151篇 |
妇产科学 | 79篇 |
基础医学 | 432篇 |
口腔科学 | 59篇 |
临床医学 | 451篇 |
内科学 | 771篇 |
皮肤病学 | 50篇 |
神经病学 | 244篇 |
特种医学 | 305篇 |
外科学 | 379篇 |
综合类 | 50篇 |
一般理论 | 2篇 |
预防医学 | 345篇 |
眼科学 | 23篇 |
药学 | 288篇 |
中国医学 | 2篇 |
肿瘤学 | 129篇 |
出版年
2023年 | 16篇 |
2022年 | 14篇 |
2021年 | 40篇 |
2020年 | 30篇 |
2019年 | 33篇 |
2018年 | 63篇 |
2017年 | 39篇 |
2016年 | 46篇 |
2015年 | 67篇 |
2014年 | 81篇 |
2013年 | 93篇 |
2012年 | 155篇 |
2011年 | 116篇 |
2010年 | 84篇 |
2009年 | 84篇 |
2008年 | 128篇 |
2007年 | 142篇 |
2006年 | 153篇 |
2005年 | 113篇 |
2004年 | 123篇 |
2003年 | 131篇 |
2002年 | 118篇 |
2001年 | 103篇 |
2000年 | 114篇 |
1999年 | 108篇 |
1998年 | 81篇 |
1997年 | 107篇 |
1996年 | 70篇 |
1995年 | 68篇 |
1994年 | 77篇 |
1993年 | 80篇 |
1992年 | 87篇 |
1991年 | 74篇 |
1990年 | 77篇 |
1989年 | 88篇 |
1988年 | 89篇 |
1987年 | 69篇 |
1986年 | 80篇 |
1985年 | 67篇 |
1984年 | 47篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1981年 | 38篇 |
1980年 | 41篇 |
1979年 | 32篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 26篇 |
1975年 | 30篇 |
1974年 | 13篇 |
排序方式: 共有3778条查询结果,搜索用时 31 毫秒
91.
92.
93.
Kyrie Rodgers Jenny Sim Ross Clifton 《Collegian (Royal College of Nursing, Australia)》2021,28(3):310-323
BackgroundPressure injuries have a major impact on patients and healthcare organisations. The complications of pressure injuries increase morbidity and mortality rates and are costly to individuals and healthcare systems. The total prevalence rate of pressure injuries within acute care hospitals in Australia and New Zealand is unknown, and despite a focus on prevention, pressure injuries still occur within these hospital settings.AimTo report the prevalence of pressure injuries within acute care settings in Australian and New Zealand hospitals and to identify the stage and location of pressure injuries and analyse the methods used to conduct pressure injury point prevalence studies.MethodsA systematic review of studies published in CINAHL, MEDLINE and Cochrane databases and a two-part grey literature search, including a customised Google search and a targeted website search, was undertaken up to July 2019. The systematic review was prospectively registered with PROSPERO (CRD42018105566).FindingsThe overall prevalence of pressure injuries in acute-care hospitals in Australia and New Zealand is 12.9% (95% CI, 9.5%–16.8%) and the hospital-acquired pressure injury prevalence is 7.9% (95% CI, 5.7%–10.3%). Stage I and stage II are the most common pressure injuries. The most frequent locations for pressure injuries are the sacrum/buttock/coccyx area (41%) and the heels (31%). The reporting of details about methodology varies considerably between studies.DiscussionPressure injuries remain a significant problem within acute-care hospital settings. Total prevalence rates are decreasing over time with the numbers of stage I and II pressure injuries decreasing faster than other pressure injuries.ConclusionThe findings from this study can be used to set performance benchmarks within acute-care hospitals in Australia and New Zealand. Pressure injuries are preventable and pressure injury prevalence studies can be used to monitor the effectiveness of nursing care processes to improve patient outcomes. 相似文献
94.
95.
Method to map antigenic determinants recognized by monoclonal antibodies: localization of a determinant of virus neutralization on the feline leukemia virus envelope protein gp70. 总被引:12,自引:3,他引:12 下载免费PDF全文
J H Nunberg G Rodgers J H Gilbert R M Snead 《Proceedings of the National Academy of Sciences of the United States of America》1984,81(12):3675-3679
A method is presented whereby antigenic determinants recognized by specific monoclonal antibodies can be mapped to specific sites on a protein sequence with high resolution. Short DNase I-generated DNA fragments encoding portions of the protein of interest are molecularly cloned into the EcoRI site of the beta-galactosidase gene of phage lambda Charon 16 so as to obtain expression of random protein fragments as fusion proteins. The monoclonal antibody is used to screen the phage library to isolate phage expressing the specific antigenic determinant. DNA of immunoreactive phage can be analyzed rapidly and subcloned to allow DNA sequence determination. The method is generally applicable and permits antigenic determinants of functionally interesting monoclonal antibodies to be mapped and related to specific protein sequences. We have used this procedure to determine the region of the feline leukemia virus envelope protein gp70 recognized by a virus-neutralizing monoclonal antibody, cl.25. Antibody binding was mapped to a 14-amino acid region in the amino-terminal half of gp70. This region may be directly involved in an essential function of the gp70 protein, perhaps in gp70-mediated host recognition functions. Synthetic peptides derived from this region may provide useful vaccine antigens for the prevention of feline leukemia virus-associated disease in cats. 相似文献
96.
97.
Wieslaw Bochenek MD John B. Rodgers Jr MD John A. Balint MB MRCP 《Digestive diseases and sciences》1971,16(10):865-872
The inhibitory effect of duodenal acidification and intraduodenal fat infusion on pentagastrin-stimulated gastric secretion in normal subjects and in patients with duodenal ulcer was studied. Intraduodenal infusion of acid resulted in inhibition of HCl secretion found to be significant only in ulcer patients. Pepsin output, although lower during the first 15 minutes of duodenal acidification, later increased. Intraduodenal infusion of olive oil resulted in significant inhibition of HCl and pepsin output in both groups of patients, which was maximal 45–60 minutes after the beginning of fat infusion. Gastric secretion was more readily inhibited in ulcer patients than in normal subjects; this difference was particularly evident in inhibition of pepsin secretion. In addition, decrease in concentration of HCl and pepsin was observed to be significant only in ulcer patients. Mechanisms by which duodenal acidification and fat inhibit gastric secretion are discussed. The results obtained suggest that secretin, which is probably responsible for inhibition after duodenal acidification, is not the inhibitor during inhibition by fat. The ulcer patients were found to have unimpaired mechanisms of inhibition by acid and fat. 相似文献
98.
Busch MP; Laycock M; Kleinman SH; Wages JW Jr; Calabro M; Kaplan JE; Khabbaz RF; Hollingsworth CG 《Blood》1994,83(4):1143-1148
Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II. 相似文献
99.