全文获取类型
收费全文 | 63363篇 |
免费 | 6675篇 |
国内免费 | 4811篇 |
专业分类
耳鼻咽喉 | 494篇 |
儿科学 | 624篇 |
妇产科学 | 599篇 |
基础医学 | 7418篇 |
口腔科学 | 1215篇 |
临床医学 | 8501篇 |
内科学 | 9944篇 |
皮肤病学 | 614篇 |
神经病学 | 3564篇 |
特种医学 | 2252篇 |
外国民族医学 | 52篇 |
外科学 | 6458篇 |
综合类 | 11169篇 |
现状与发展 | 19篇 |
一般理论 | 5篇 |
预防医学 | 4441篇 |
眼科学 | 1872篇 |
药学 | 6891篇 |
39篇 | |
中国医学 | 3466篇 |
肿瘤学 | 5212篇 |
出版年
2024年 | 267篇 |
2023年 | 1170篇 |
2022年 | 2725篇 |
2021年 | 3428篇 |
2020年 | 2604篇 |
2019年 | 2258篇 |
2018年 | 2255篇 |
2017年 | 2091篇 |
2016年 | 1983篇 |
2015年 | 2981篇 |
2014年 | 3711篇 |
2013年 | 3162篇 |
2012年 | 4911篇 |
2011年 | 5300篇 |
2010年 | 3140篇 |
2009年 | 2434篇 |
2008年 | 3363篇 |
2007年 | 3221篇 |
2006年 | 3164篇 |
2005年 | 3117篇 |
2004年 | 2032篇 |
2003年 | 1972篇 |
2002年 | 1629篇 |
2001年 | 1393篇 |
2000年 | 1430篇 |
1999年 | 1638篇 |
1998年 | 999篇 |
1997年 | 966篇 |
1996年 | 698篇 |
1995年 | 643篇 |
1994年 | 643篇 |
1993年 | 394篇 |
1992年 | 564篇 |
1991年 | 426篇 |
1990年 | 389篇 |
1989年 | 326篇 |
1988年 | 317篇 |
1987年 | 256篇 |
1986年 | 217篇 |
1985年 | 181篇 |
1984年 | 98篇 |
1983年 | 60篇 |
1982年 | 45篇 |
1981年 | 41篇 |
1980年 | 19篇 |
1979年 | 42篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1964年 | 7篇 |
1936年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Exaggerated neurogenic inflammation and substance P receptor upregulation in RSV-infected weanling rats 总被引:5,自引:0,他引:5
King KA Hu C Rodriguez MM Romaguera R Jiang X Piedimonte G 《American journal of respiratory cell and molecular biology》2001,24(2):101-107
Respiratory syncytial virus (RSV) infection in adult rats causes exaggerated inflammation after sensory nerve stimulation in the extrapulmonary, but not in the intrapulmonary airways. The goal of this study was to analyze neurogenic inflammation in weanling F-344 rats infected with RSV 18 +/- 2 d after birth. Five days after RSV inoculation, the extravasation of Evans blue-labeled albumin after nerve stimulation was significantly greater in the intrapulmonary airways of RSV-infected weanling rats than in pathogen-free control rats. In contrast, no difference was found in the extrapulmonary airways. The level of messenger RNA (mRNA) encoding the substance P (SP) receptor (neurokinin 1 [NK1]) increased fourfold in RSV-infected lungs, whereas mRNA encoding the VIPR1 receptor for the antiinflammatory vasoactive intestinal peptide (VIP) increased to a much lesser degree. mRNAs encoding the other neurokinin (NK2) and VIP (VIPR2) receptors were not affected by the virus. Selective inhibition of the NK1 receptor abolished neurogenic inflammation in RSV-infected intrapulmonary airways. Also, neurogenic inflammation and NK1 receptor upregulation in infected lungs were inhibited by prophylaxis with a monoclonal antibody against RSV. These data suggest that RSV lower respiratory tract infection makes the intrapulmonary airways of young rats abnormally susceptible to the proinflammatory effects of SP by selectively upregulating the expression of NK1 receptors. 相似文献
102.
Cytogenetic analysis of a uterine lipoleiomyoma. 总被引:2,自引:0,他引:2
We cytogenetically analyzed a uterine lipoleiomyoma. A primary chromosomal abnormality, t(12;14), was found in all 62 cells studied. A secondary change involving chromosomes 1 and 5 was detected in 15 of 62 cells. These findings suggest that lipoleiomyomas share the same chromosomal abnormalities found in common leiomyomas. We speculate that the secondary chromosomal change involving chromosomal 5 may be responsible for the lipomatous change. 相似文献
103.
Apodemus species mice are reservoir hosts of Borrelia garinii OspA serotype 4 in Switzerland 下载免费PDF全文
Among Borrelia burgdorferi sensu lato isolates, seven outer surface protein A (OspA) serotypes have been described: serotypes 1 and 2 correspond to B. burgdorferi sensu stricto and Borrelia afzelii, respectively, and serotypes 3 to 7 correspond to Borrelia garinii. In Europe, serotype 4 has never been isolated from Ixodes ricinus ticks until recently, although this serotype has been frequently isolated from cerebrospinal fluid from patients. In Europe, B. afzelii and B. burgdorferi sensu stricto were found associated with rodents and B. garinii was found associated with birds. In this study, the reservoir role of Apodemus mice for B. garinii OspA serotype 4 was demonstrated by xenodiagnosis. Apodemus mice are the first identified reservoir hosts for B. garinii OspA serotype 4. 相似文献
104.
Encapsidation of human immunodeficiency virus type 1 (HIV-1) RNA involves specific interactions between viral Gag proteins and viral RNA elements located at the 5' untranslated region (UTR). These RNA elements are termed packaging (psi) or encapsidation (E) signals and mainly comprise the stem-loop 1 (SL1) and SL3 RNA structures. We have previously shown that deletion of the SL1 sequences is compensated by second-site mutations within Gag. Similar studies are now extended to SL3 and the results demonstrate that deletion of this RNA structure is rescued by two point mutations, i.e., A11V in p2 and I12V in nucleocapsid (NC). These two compensatory mutations are different from those associated with the rescue of SL1 deletion, suggesting that SL1 and SL3 may bind to different residues of Gag during viral RNA packaging. Analysis of virion-derived RNA in native agarose gels shows that deletion of SL3 leads to decreases in both viral RNA packaging and dimerization. These defects are corrected by the compensatory mutations A11V and I12V. Yet, defects in viral RNA dimerization at an early stage that were caused by the SL3 deletion in the context of a viral protease-negative mutation cannot be overcome by these two suppressor mutations. Therefore, the positive effects of A11V and I12V on dimerization of the SL3-deleted RNA must have taken place at the maturation stage. 相似文献
105.
VALUE AND LIMITATIONS OF SINUS NODE FUNCTION TE.ST
BY ATRIAL PACING IN SICK SINUS SYNDROME DIAGNOSIS
Sun Rui-long孙瑞龙 Chen Xin陈新 Wang Fang-zhengHu Sheng-jun胡绳俊 Tian Rui-guo田瑞国and Qi Lian-xiaClinical Electrophysiology Laborato''ry Institute of Cardiovascular Diseases Chinese Academy of Medical Sciences Beijing 《中华医学杂志(英文版)》1984,97(2):142-146
In order to evaluate the significance of the
sinus node function test by transvenous atrial
pacing in the diagno,sis of sick sinus syndrome
(SSS), sinus node recovery time (SRT), co]rrected
sinus node recovery time (CSRT) and total atrio-
sinus and sino-atrial conduction time (SACT)
are observed in 69 patients including non-SSS
group 39 cases and SSS group 30 cases.
According to our data, we suggest criteria
for sinus node dysfunction as follows. SRT>1,400
ms and/or A-V junctional esca.pe before sinus
recovery and;or secondary pause, CSRT>560 ms.
total SACT>300 ms. With l item abnormal, the
false positive rat.e in the non-SSS group is 7.7c7。
and the false negative rate in the S.SS group 3.30i"
with 2 items abnormal, the false positive rate in
the non-SSS group Oi and the false negative
rate in the SSS grOiup 6.7'70.
Atropine test results are compared with that
of atrial pacing, 95.8To and 84.2% are compatible
with each other in these 2 groups. In order to
cut the use of invasive technic to the minimum,
we propose performing the atropine test first.
Only in those with unexplainable test results
should the trial pacing test. be resorted to.. 相似文献
106.
Quality of Life Research - To summarize the current evidence regarding the effectiveness of intradialytic exercise (IDE) on the health-related quality of life (HRQOL) of patients undergoing... 相似文献
107.
Xin-Ran Liu Na Zhu Yun-Tao Hao Xiao-Chen Yu Zhen Li Rui-Xue Mao Rui Liu Jia-Wei Kang Jia-Ni Hu Yong Li 《Nutrients》2021,13(3)
Radiation therapy is widely used in the treatment of tumor diseases, but it can also cause serious damage to the body, so it is necessary to find effective nutritional supplements. The main purpose of this study is to evaluate the protective effect of whey hydrolysate peptides (WHPs) against 60Coγ radiation damage in mice and explore the mechanism. BALB/c mice were given WHPs by oral gavage administration for 14 days. Then, some mice underwent a 30-day survival test after 8 Gy radiation, and other mice received 3.5 Gy radiation to analyze the changes in body weight, hematology and bone marrow DNA after three and 14 days. In addition, through further analysis of the level of oxidative stress and intestinal barrier function, the possible mechanism of the radioprotective effect of WHPs was explored. The study found WHPs can prolong survival time, restore body weight, and increase the number of peripheral blood white blood cells and bone marrow DNA content in irradiated mice. In addition, WHPs can significantly improve the antioxidant capacity, inhibit pro-inflammatory cytokines and protect the intestinal barrier. These results indicate that WHPs have a certain radioprotective effect in mice, and the main mechanism is related to reducing oxidative damage. 相似文献
108.
Oneofthereasonsforfailureofchemotherapyintreatingleukemiaisthattheleukemiccellspresentdrugtolerancetochemotherapeuticagents.Thecur renthotpointofanti leukemicdrugtoleranceresearchismultidrugresistance(MDR).MDRcouldbegen erallydividedaccordingtoitsmech… 相似文献
109.
Long or highly irregular menstrual cycles as a marker for risk of type 2 diabetes mellitus. 总被引:10,自引:0,他引:10
C G Solomon F B Hu A Dunaif J Rich-Edwards W C Willett D J Hunter G A Colditz F E Speizer J E Manson 《JAMA》2001,286(19):2421-2426
CONTEXT: Although oligomenorrhea has been associated cross-sectionally with insulin resistance and glucose intolerance, it is not known whether oligomenorrhea is a marker for increased future risk of type 2 diabetes mellitus (DM). OBJECTIVE: To prospectively assess risk of type 2 DM in women with a history of long or highly irregular menstrual cycles. DESIGN AND SETTING: The Nurses' Health Study II, a prospective observational cohort study. PARTICIPANTS: A total of 101 073 women who had no prior history of DM and who reported their usual menstrual cycle pattern at age 18 to 22 years on the baseline (1989) questionnaire. MAIN OUTCOME MEASURE: Incident reports of DM, with follow-up through 1997, compared among women categorized by menstrual cycle length (5 categories). RESULTS: During 564 333 person-years of follow-up, there were 507 cases of type 2 DM. Compared with women with a usual cycle length of 26 to 31 days (referent category) at age 18 to 22 years, the relative risk (RR) of type 2 DM among women with a menstrual cycle length that was 40 days or more or was too irregular to estimate was 2.08 (95% confidence interval [CI], 1.62-2.66), adjusting for body mass index at age 18 years and several other potential confounding variables. The RR of type 2 DM associated with long or highly irregular menstrual cycles was greater in obese women, but was also increased in nonobese women (at body mass indexes at age 18 years of <25, 25-29, and >/=30 kg/m, RRs were 1.67 [95% CI, 1.14-2.45], 1.74 [95% CI, 1.07-2.82], and 3.86 [95% CI, 2.33-6.38], respectively). CONCLUSION: Women with long or highly irregular menstrual cycles have a significantly increased risk for developing type 2 DM that is not completely explained by obesity. 相似文献
110.
Yu Jin Zhengyi Feng Ju Zhao Jinxiao Hu Yuanyuan Tong Shengwen Guo Peiyao Zhang Liting Bai Yixuan Li Jinping Liu 《Artificial organs》2021,45(1):6-14
Mortality and morbidity of children received veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) support after cardiac surgery remain high despite remarkable advances in medical management and devices. The purpose of this study was to describe outcomes and risk factors of applying VA‐ECMO in the surgical pediatric population. We retrospectively analyzed 85 consecutive pediatric patients (aged <18 years) who received postcardiotomy VA‐ECMO from January 2010 to December 2018. Median (IQR) age at ECMO implantation in this cohort was 12.7 (6.4, 43.2) months, median weight was 8.5 (6.0, 12.8) kg, mean ECMO duration was 143.2 ± 81.6 hours and mean hospital length of stay was 48.4 ± 32.4 days. Seventy‐five patients (88.2%) were indicated for postcardiotomy cardiogenic shock. The successful ECMO weaning rate was 70.6% and in‐hospital mortality was 52.9%. The most common diagnosis was transposition of great arteries (n = 18, 21.2%), while acute kidney injury occurred most often (n = 64, 75.3%). Multivariate logistic regression analysis showed that thrombocytopenia, hemolysis, and nosocomial infection were positively correlated with in‐hospital mortality. Multivariate Cox proportional hazard regression analysis presented that thrombocytopenia significantly increased the 180‐day mortality in patients with successful weaning. Therefore, multiple factors had adverse effects on prognosis. Patient selection and procedures from ECMO implantation to weaning need to be closely monitored and performed in a timely manner to improve outcome. 相似文献