全文获取类型
收费全文 | 21655篇 |
免费 | 1531篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 291篇 |
儿科学 | 677篇 |
妇产科学 | 344篇 |
基础医学 | 2635篇 |
口腔科学 | 533篇 |
临床医学 | 2380篇 |
内科学 | 4061篇 |
皮肤病学 | 316篇 |
神经病学 | 2012篇 |
特种医学 | 722篇 |
外科学 | 3542篇 |
综合类 | 305篇 |
一般理论 | 19篇 |
预防医学 | 1883篇 |
眼科学 | 472篇 |
药学 | 1702篇 |
中国医学 | 18篇 |
肿瘤学 | 1339篇 |
出版年
2023年 | 107篇 |
2022年 | 168篇 |
2021年 | 455篇 |
2020年 | 255篇 |
2019年 | 466篇 |
2018年 | 542篇 |
2017年 | 375篇 |
2016年 | 391篇 |
2015年 | 474篇 |
2014年 | 720篇 |
2013年 | 977篇 |
2012年 | 1552篇 |
2011年 | 1524篇 |
2010年 | 855篇 |
2009年 | 784篇 |
2008年 | 1428篇 |
2007年 | 1446篇 |
2006年 | 1481篇 |
2005年 | 1454篇 |
2004年 | 1359篇 |
2003年 | 1172篇 |
2002年 | 1098篇 |
2001年 | 243篇 |
2000年 | 242篇 |
1999年 | 261篇 |
1998年 | 251篇 |
1997年 | 186篇 |
1996年 | 161篇 |
1995年 | 146篇 |
1994年 | 143篇 |
1993年 | 130篇 |
1992年 | 141篇 |
1991年 | 147篇 |
1990年 | 137篇 |
1989年 | 127篇 |
1988年 | 141篇 |
1987年 | 124篇 |
1986年 | 109篇 |
1985年 | 106篇 |
1984年 | 117篇 |
1983年 | 106篇 |
1982年 | 97篇 |
1981年 | 102篇 |
1980年 | 81篇 |
1979年 | 81篇 |
1978年 | 79篇 |
1977年 | 59篇 |
1975年 | 59篇 |
1973年 | 64篇 |
1972年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review. 相似文献
6.
Charlotte J. Harden Bernard M. Corfe J. Craig Richardson Peter W. Dettmar Jenny R. Paxman 《Nutrition Research》2009
This cross-sectional analysis evaluated the effect of age and body mass index (BMI) on Three-Factor Eating Questionnaire scores in males. Subjects (n = 60) were recruited according to BMI status. Each completed the 51-item Three-Factor Eating Questionnaire. The group was split at the median age to produce a “younger” and “older” group for statistical analysis. A 2-way between-groups analysis of variance revealed a significant main effect of BMI on disinhibition (P = .003) and hunger (P = .041) with higher levels found in overweight males compared to healthy-weight counterparts. A significant main effect of age on hunger (P = .046) demonstrated older males were less susceptible to hunger than younger males. These insights provide a better understanding of eating behavior across the male life cycle and may assist health professionals to better guide men in weight management in the light of rising overweight/obesity. 相似文献
7.
8.
PACAP is a hypothalamic hypophysiotropic factor that acts upon a number of pituitary cells, including gonadotrophs. In the gonadotroph-derived αT3-1 cell line, PACAP acts via PVR1 receptors to stimulate adenylyl cyclase and phosphoinositidase C. PACAP-stimulated cAMP accumulation is inhibited by protein kinase C-activating phorbol esters in these cells and the current work was undertaken primarily to establish whether it is also subject to homologous regulation. In acute experiments, PACAP27-stimulated cAMP accumulation (intracellular plus extracellular) was measured (in the presence of phosphodiesterase inhibitor) both in intact cells and in cell membranes. The peptide increased cAMP accumulation, but initial rates of PACAP27-stimulated cAMP accumulation were reduced to between 10 and 50% within 10 min of stimulation in both cells and membranes. The initial rate of forskolin-stimulated cAMP accumulation was maintained in membranes but not in intact cells (although the deviation from linearity was less pronounced than with PACAP27). Thus, rapid homologous desensitization to PACAP27 occurs in intact αT3-1 cells, but is not entirely receptor specific. Rapid homologous desensitization of PACAP27-stimulated cAMP accumulation also occurred in the presence of a protein kinase C activating phorbol ester, which inhibited cAMP accumulation without altering the kinetics of the PACAP27 effect. Brief pre-treatment (3 min) with PACAP27 also reduced the ability of PACAP27, but not gonadotrophin-releasing hormone, to cause a spike-type elevation of cytosolic Ca2+ concentration (a consequence of phosphoinositidase C activation). In chronic desensitization studies, pre-treatment for 6 h with PACAP27 caused a dose-dependent (IC50 approximately 10 nM) reduction of PACAP-stimulated cAMP accumulation and down regulated cell surface PVR1 receptors (to approximately 50%). Thus, it appears that PACAP27-stimulated (PVR-1 receptor mediated) adenylyl cyclase undergoes rapid homologous desensitization in αT3-1 cells, which is paralleled by homologous desensitization of PACAP27-stimulated phosphoinositidase C activity and involves mechanisms distinct from those underlying heterologous desensitization by phorbol esters. Chronic desensitization of PACAP-stimulated cAMP accumulation and down-regulation of cell surface PVR-1 receptors also occurs in these cells although the receptor loss may not entirely explain the observed desensitization. 相似文献
9.
C J Craig 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(5):237-240
In order for cytological examination of a cervical smear to be an adequate method of screening for pre-invasive lesions, the smear must contain both squamous and endocervical cells. Figures obtained for 1988 indicated that in South Africa 45% of smears do not contain endocervical cells. The study reported, in which the same patients were compared in successive years but using different techniques, showed that with the use of biomedically designed tools 98.3% of smears can be classified as adequate. 相似文献
10.
The MMPIs of 104 cocaine abusers in treatment were subjected to a hierarchical cluster analysis and two basic profile types emerged. Type I consisted of a spike on Pd and a subspike on Hyp, reflecting a rebellious, acting out character-disordered style with narcissistic traits. Type II consisted of a high-ranging, floating profile consisting of marked elevations on F, Sc, Dep, Pt, Pd, and Pa, reflecting a psychiatric patient who concurrently abused cocaine. These findings were contrasted to other MMPI typological studies, and the similarities and differences were discussed. 相似文献