全文获取类型
收费全文 | 19340篇 |
免费 | 1530篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 211篇 |
儿科学 | 607篇 |
妇产科学 | 377篇 |
基础医学 | 3238篇 |
口腔科学 | 443篇 |
临床医学 | 1961篇 |
内科学 | 4095篇 |
皮肤病学 | 429篇 |
神经病学 | 1645篇 |
特种医学 | 680篇 |
外国民族医学 | 1篇 |
外科学 | 2402篇 |
综合类 | 129篇 |
一般理论 | 11篇 |
预防医学 | 1469篇 |
眼科学 | 385篇 |
药学 | 1496篇 |
中国医学 | 22篇 |
肿瘤学 | 1315篇 |
出版年
2023年 | 100篇 |
2022年 | 163篇 |
2021年 | 341篇 |
2020年 | 264篇 |
2019年 | 328篇 |
2018年 | 361篇 |
2017年 | 342篇 |
2016年 | 405篇 |
2015年 | 451篇 |
2014年 | 580篇 |
2013年 | 740篇 |
2012年 | 1066篇 |
2011年 | 1078篇 |
2010年 | 620篇 |
2009年 | 580篇 |
2008年 | 949篇 |
2007年 | 1018篇 |
2006年 | 885篇 |
2005年 | 904篇 |
2004年 | 918篇 |
2003年 | 811篇 |
2002年 | 761篇 |
2001年 | 457篇 |
2000年 | 481篇 |
1999年 | 449篇 |
1998年 | 252篇 |
1997年 | 197篇 |
1996年 | 200篇 |
1995年 | 182篇 |
1994年 | 172篇 |
1993年 | 158篇 |
1992年 | 321篇 |
1991年 | 351篇 |
1990年 | 342篇 |
1989年 | 346篇 |
1988年 | 272篇 |
1987年 | 285篇 |
1986年 | 247篇 |
1985年 | 299篇 |
1984年 | 203篇 |
1983年 | 173篇 |
1982年 | 133篇 |
1981年 | 111篇 |
1980年 | 98篇 |
1979年 | 171篇 |
1978年 | 126篇 |
1977年 | 110篇 |
1975年 | 102篇 |
1974年 | 120篇 |
1973年 | 108篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Interprofessional collaboration and communication in nursing homes: a qualitative exploration of problems in medical care for nursing home residents – study protocol 下载免费PDF全文
3.
Christian Holm Hansen Shelley Lees Saidi Kapiga Janet Seeley Tony Barnett 《Global public health》2020,15(3):402-413
ABSTRACTMeasuring hope reliably and accurately remains an important research objective, not least in less prosperous settings where ‘holding on to hope’ may be critically important in the struggle against adverse life conditions. The State Hope Scale was designed for use in the US. Despite reported application in diverse cultures and using translations the scale has not been extensively validated outside US populations. This study contributes to a larger project exploring the measurement of hope and provides a critique of Snyder’s scale as used in a Tanzanian female population of 1021 urban microfinance participants. We evaluate the scale’s validity through assessment of the empirical distribution of scores, item response profiles, internal consistency and discriminatory ability. Participants mostly scored very high and many reached very near the maximum attainable score. Hardly any endorsed the negative half of the response scale. Several problems are discussed including poor discrimination and strong evidence of acquiescence response bias. We also found little association of the scale scores with hypothesised correlates of hope. Future improvements on the measurement of hope are recommended, especially in studies outside the narrow Western context in which the scale was devised. 相似文献
4.
Non‐melanoma skin cancer frequently results from chronic exposure to ultraviolet (UV) irradiation. UV‐induced DNA damage activates cell cycle arrest checkpoints through degradation of the cyclin‐dependent kinase activators, the cell division cycle 25 (CDC25) phosphatases. We previously reported increased CDC25A in nonmelanoma skin cancer, but CDC25B and CDC25C had not been previously examined. Consequently, we hypothesized that increased expression of CDC25B and CDC25C increases tumor cell proliferation and skin tumor growth. We found that CDC25B and CDC25C were increased in mouse and human skin cancers. CDC25B was primarily cytoplasmic in skin and skin tumors and was significantly increased in the squamous cell carcinoma (SCC), while CDC25C was mostly nuclear in the skin, with an increased cytoplasmic signal in the premalignant and malignant tumors. Surprisingly, forced expression of CDC25B or CDC25C in cultured SCC cells did not affect proliferation, but instead suppressed apoptosis, while CDC25C silencing increased apoptosis without impacting proliferation. Targeting CDC25C to the nucleus via mutation of its nuclear export sequence, however, increased proliferation in SCC cells. Overexpression of CDC25C in the nuclear compartment did not hinder the ability of CDC25C to suppress apoptosis, neither did mutation of sites necessary for its interaction with 14‐3‐3 proteins. Analysis of apoptotic signaling pathways revealed that CDC25C increased activating phosphorylation of Akt on Ser473, increased inhibitory phosphorylation of proapoptotic BAD on Ser136, and increased the survival protein Survivin. Silencing of CDC25C significantly reduced Survivin levels. Taken together, these data suggest that increased expression of CDC25B or CDC25C are mechanisms by which skin cancers evade apoptotic cell death. 相似文献
5.
Vincent Laville Sigrid Le Clerc Khaled Ezzedine Randa Jdid Lieng Taing Toufik Labib Cdric Coulonges Damien Ulveling Pilar Galan Christiane Guinot Leopold Fezeu Frdrique Morizot Julie Latreille Denis Malvy Erwin Tschachler Jean‐Franois Zagury 《Experimental dermatology》2019,28(8):892-898
Sagging eyelid is considered as an outward of skin ageing and may cause medical issues. However, little is known about the factors involved in sagging eyelid. The study, which aims at determining genetic risk factors for eyelid sagging, was conducted in a cohort of 502 unrelated Caucasian women living in the Paris region. All included participants were aged between 44 and 70 years old (mean age, 57.6 years old). The severity of sagging eyelid was graded in 6 categories by a dermatologist using standardized photographs of the face. A genome wide association study adjusted on potential risk factors (including age and smoking habits) was conducted to identify genetic associations. Two single nucleotide polymorphisms in total linkage disequilibrium on chromosome 10, rs16927253 (P = 7.07 × 10‐10) and rs4746957 (P = 1.06 × 10‐8), were significantly associated with eyelid sagging severity. The rs16927253‐T and rs4746957‐A alleles showed a dominant protective effect towards eyelid sagging. These polymorphisms are located in intronic parts of the H2AFY2 gene which encodes a member of the H2A histone family and very close to the AIFM2 gene that induces apoptosis. Additionally, single nucleotide polymorphisms with a false discovery rate below 0.25 were located nearby the type XIII collagen COL13A1 gene on chromosome 10 and in the ADAMTS18 gene on chromosome 16. Several relevant genes were identified by the genome wide association study for their potential role in the sagging eyelid severity. 相似文献
6.
Baha’ N. Noureddin Christiane E. Al-Haddad Ziad Bashshur Bared Safieh-Garabedian 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2006,244(6):750-752
Background The objective was to measure the plasma concentrations of thymulin and nerve growth factor (NGF) in a group of patients with primary open angle glaucoma (POAG) and compare them with age- and sex-matched normal controls.Methods Twenty-eight patients newly diagnosed with POAG who were not undergoing treatment were compared with the same number of age- and sex-matched healthy controls. Blood samples were drawn into heparinized tubes and plasma samples were collected for the determination of the concentrations of thymulin and NGF, using specific enzyme-linked immunosorbent assay (ELISA). The Student’s t test was used to perform the necessary statistical analysis of the results.Results Seventeen women and 11 men were enrolled in each of the two groups (study and control), with a mean age of 63.7 (SD 10.3) years in the former and 63.3 (SD 9.6) years in the latter. There was a highly significant (p<0.001) elevation in the thymulin levels in POAG patients compared with the control group. However, no significant difference was observed when comparing the plasma NGF levels.Conclusion This is the first report to measure plasma thymulin levels in glaucoma patients. The significant results point the possible role of this immunomodulator in the pathogenesis of primary open angle glaucoma. The potential role of NGF seems to be less likely. These findings warrant further investigation. 相似文献
7.
8.
Clinical versus ultrasonographic evaluation of scrotal disorders 总被引:1,自引:0,他引:1
B Kromann-Andersen L B Hansen P N Larsen K Lawetz P Lynge D Lysen S P Nielsen K H Stockholm P Foged 《British journal of urology》1988,61(4):350-353
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings. 相似文献
9.
10.
P.J. Hansen P. Soto . 《American journal of reproductive immunology (New York, N.Y. : 1989)》2002,48(3):150-150
Increased peripheral NK cells in aborting women are considered as a predictor of immunological miscarriages. Here, we investigated the diagnostic value of the NK count at the time of abortion. Peripheral NK cells were counted by flow cytometry in 44 women undergoing therapeutic termination of first trimester missed pregnancy (A = 24) or elective abortion (B = 20). Histology of the extracted material was performed and immunological lesions (villitis, intervillositis, vascular thrombosis, increased fibrinoid necrosis) were recorded. Twenty first trimester pregnant women (C1) and 20 nonpregnant women (C2) served as controls. In 20 women of groups A and B (A1 = 10, B2 = 10) count was repeated after 5 days. At abortion time, the NK percentage and number did not differ between groups A and B (18.18%, 360 versus 15.61%, 374), but there was a statistically significant difference between A and C1 (18.18% versus 13.6%, P < 0.03). When histology negative (11) and positive (8) cases were excluded from groups A and B, respectively, NKs were slightly higher in group A (18.18–19.76%) and significantly lower in B (15.61–13.07%, P < 0.05). At the time of second count, aborters' NKs decreased (A1 = 16.64 versus 13.6 and 10.6 in groups C1 and C2 –P = 0.01, respectively). In group B, NK percentage was equal to that of nonpregnant women (10.94 versus 10.6). At the time of abortions, NKs increase only in cases of immune‐mediated miscarriages. Their – in time – count may contribute to the diagnosis of immmunological abortions. 相似文献