全文获取类型
收费全文 | 3095篇 |
免费 | 315篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 113篇 |
妇产科学 | 45篇 |
基础医学 | 435篇 |
口腔科学 | 50篇 |
临床医学 | 454篇 |
内科学 | 497篇 |
皮肤病学 | 60篇 |
神经病学 | 203篇 |
特种医学 | 167篇 |
外科学 | 389篇 |
综合类 | 75篇 |
一般理论 | 3篇 |
预防医学 | 398篇 |
眼科学 | 11篇 |
药学 | 225篇 |
2篇 | |
肿瘤学 | 273篇 |
出版年
2021年 | 45篇 |
2020年 | 40篇 |
2019年 | 42篇 |
2018年 | 43篇 |
2017年 | 45篇 |
2016年 | 44篇 |
2015年 | 46篇 |
2014年 | 73篇 |
2013年 | 98篇 |
2012年 | 139篇 |
2011年 | 146篇 |
2010年 | 88篇 |
2009年 | 83篇 |
2008年 | 147篇 |
2007年 | 135篇 |
2006年 | 140篇 |
2005年 | 136篇 |
2004年 | 112篇 |
2003年 | 115篇 |
2002年 | 105篇 |
2001年 | 102篇 |
2000年 | 104篇 |
1999年 | 104篇 |
1998年 | 60篇 |
1997年 | 50篇 |
1996年 | 37篇 |
1995年 | 41篇 |
1994年 | 39篇 |
1993年 | 30篇 |
1992年 | 95篇 |
1991年 | 80篇 |
1990年 | 80篇 |
1989年 | 89篇 |
1988年 | 65篇 |
1987年 | 58篇 |
1986年 | 45篇 |
1985年 | 48篇 |
1984年 | 33篇 |
1983年 | 31篇 |
1982年 | 25篇 |
1981年 | 19篇 |
1980年 | 19篇 |
1979年 | 45篇 |
1978年 | 18篇 |
1977年 | 28篇 |
1976年 | 25篇 |
1975年 | 28篇 |
1974年 | 27篇 |
1973年 | 24篇 |
1967年 | 18篇 |
排序方式: 共有3416条查询结果,搜索用时 15 毫秒
21.
Y Z Patt C M McBride F C Ames L J Claghorn K R Cleary A W Boddie C Charnsangavej G M Mavligit 《Cancer》1987,59(5):867-873
Twenty patients with colon cancer metastatic to the liver underwent successful hepatic resection and adjuvant perioperative therapy that included hepatic arterial mitomycin C and floxuridine (FUDR). The median survival for all 20 patients was 51 months: 10 are still alive with a median postoperative follow-up of 49 months; 6 are disease-free with a median postoperative follow-up of 43 months. Among 10 patients in whom the surgical margins of the specimen contained tumor cells, the median survival was 52 months. This survival was comparable to that among 10 patients in whom the surgical margins were tumor free (P = 0.22). Neither the number of metastatic liver deposits nor the disease-free interval between the primary diagnosis of colorectal carcinoma and the development of liver metastases significantly affected survival. A transient chemical hepatitis which resolved before the next scheduled treatment was associated with 50% of arterial chemotherapy cycles (approximately 70% of the patients). Gastric or duodenal ulcerations occurred in 23% of the patients. Surgical complications were either pulmonary such as pleural effusion or atelectasis, or wound infections and subphrenic abscesses. Although these results compare favorably with the results in previously published series, this aggressive adjuvant chemotherapy appears to be particularly justified in patients with tumor positive surgical margins or those with multiple tumor masses and, therefore, are characterized by a poor prognosis. 相似文献
22.
Differences in preconceptional and prenatal behaviors in women with intended and unintended pregnancies. 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
W L Hellerstedt P L Pirie H A Lando S J Curry C M McBride L C Grothaus J C Nelson 《American journal of public health》1998,88(4):663-666
OBJECTIVES: This study examined whether pregnancy intention was associated with cigarette smoking, alcohol drinking, use of vitamins, and consumption of caffeinated drinks prior to pregnancy and in early pregnancy. METHODS: Data from a telephone survey of 7174 pregnant women were analyzed. RESULTS: In comparison with women whose pregnancies were intended, women with unintended pregnancies were more likely to report cigarette smoking and less likely to report daily vitamin use. Women with unintended pregnancies were also less likely to decrease consumption of caffeinated beverages or increase daily vitamin use. CONCLUSIONS: Pregnancy intention was associated with health behaviors, prior to pregnancy and in early pregnancy, that may influence pregnancy course and birth outcomes. 相似文献
23.
Incidence and determinants of moderate COPD (GOLD II) in male smokers aged 40–65 years: 5-year follow up
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roeland MM Geijer Alfred PE Sachs Theo JM Verheij Philippe L Salom Jan-Willem J Lammers Arno W Hoes 《The British journal of general practice》2006,56(530):656-661
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major health problem with an estimated prevalence of 10-15% among smokers. The incidence of moderate COPD, as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), is largely unknown. AIM: To determine the cumulative incidence of moderate COPD (forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC] <0.7 and FEV1 <80% predicted) and its association with patient characteristics in a cohort of male smokers. DESIGN: Prospective cohort study. SETTING: The city of IJsselstein, a small town in the Netherlands. METHOD: Smokers aged 40-65 years who were registered with local GPs, participated in a study to identify undetected COPD. Baseline measurements were taken in 1998 of 399 smokers with normal spirometry (n = 292) or mild COPD (FEV1/FVC <0.7 and FEV1 >or=80% predicted, n = 107) and follow-up measurements were conducted in 2003. RESULTS: After a mean follow-up of 5.2 years, 33 participants developed moderate COPD (GOLD II). This showed an estimated cumulative incidence of 8.3% (95% CI = 5.8 to 11.4) and a mean annual incidence of 1.6%. No participant developed severe airflow obstruction. The risk of developing moderate COPD in smokers with baseline mild COPD (GOLD I) was five times higher than in those with baseline normal spirometry (one in five versus one in 25). CONCLUSIONS: In a cohort of middle-aged male smokers, the estimated cumulative incidence of moderate COPD (GOLD II) over 5 years was relatively high (8.3%). Age, childhood smoking, cough, and one or more GP contacts for lower respiratory tract problems were independently associated with incident moderate COPD. 相似文献
24.
Interleukin-4 downregulates interleukin-6 production in human peripheral blood mononuclear cells 总被引:5,自引:0,他引:5
J D Lee S G Swisher E H Minehart W H McBride J S Economou 《Journal of leukocyte biology》1990,47(5):475-479
We report that recombinant human interleukin-4 (IL-4) downregulates interleukin-6 (IL-6) production by human peripheral blood mononuclear cells (PBMC). PBMC were preincubated for up to 24 hr in the presence of IL-4 (100 U/ml) and then activated with lipopolysaccharide B Escherichia coli 026:B6 (LPS, 10 micrograms/ml), recombinant human tumor necrosis factor-alpha (TNF-alpha, 200 U/ml), or Concanavalin A (Con A, 10 micrograms/ml). Although all these signals induced IL-6 production, IL-4-treated cells produced significantly reduced levels of IL-6 protein. This effect was dose and time dependent. We conclude that IL-4 is a potent downregulatory modulator of IL-6 expression in human PBMC. 相似文献
25.
Chest radiography in general practice: indications, diagnostic yield and consequences for patient management
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anouk M Speets Yolanda van der Graaf Arno W Hoes Sandra Kalmijn Alfred PE Sachs Matthieu JCM Rutten Jan Willem C Gratama Alexander D Montauban van Swijndregt Willem PThM Mali 《The British journal of general practice》2006,56(529):574-578
BACKGROUND: Chest radiography (CXR) is frequently performed in Western societies. There is insufficient knowledge of its diagnostic value in terms of changes in patient management decisions in primary care. AIM: To assess the influence of CXR on patient management in general practice. DESIGN OF STUDY: Prospective cohort study. SETTING: Seventy-eight GPs and three general hospitals in the Netherlands. METHOD: Patients (n = 792) aged > or =18 years referred by their GPs for CXR were included. The main outcome was change in patient management assessed by means of questionnaires filled in by GPs before and after CXR. RESULTS: Mean age of the patients was 57.3+/-16.2 years and 53% were male. Clinically relevant abnormalities were found in 24% of the CXRs. Patient management changed in 60% of the patients following CXR. Main changes included: fewer referrals to a medical specialist (from 26 to 12%); reduction in initiation or change in therapy (from 24 to 15%); and more frequent reassurance (from 25 to 46%). However, this reassurance was not perceived as such in a quarter of these patients. A change in patient management occurred significantly more frequently in patients with complaints of cough (67%), those who exhibited abnormalities during physical examination (69%), or those with a suspected diagnosis of pneumonia (68%). CONCLUSION: Patient management by the GP changed in 60% of patients following CXR. CXR substantially reduced the number of referrals and initiation or change in therapy, and more patients were reassured by their GP. Thus, CXR is an important diagnostic tool for GPs and seems a cost-effective diagnostic test. 相似文献
26.
27.
The clinical-grade 42-kilodalton fragment of merozoite surface protein 1 of Plasmodium falciparum strain FVO expressed in Escherichia coli protects Aotus nancymai against challenge with homologous erythrocytic-stage parasites 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Darko CA Angov E Collins WE Bergmann-Leitner ES Girouard AS Hitt SL McBride JS Diggs CL Holder AA Long CA Barnwell JW Lyon JA 《Infection and immunity》2005,73(1):287-297
A 42-kDa fragment from the C terminus of major merozoite surface protein 1 (MSP1) is among the leading malaria vaccine candidates that target infection by asexual erythrocytic-stage malaria parasites. The MSP1(42) gene fragment from the Vietnam-Oak Knoll (FVO) strain of Plasmodium falciparum was expressed as a soluble protein in Escherichia coli and purified according to good manufacturing practices. This clinical-grade recombinant protein retained some important elements of correct structure, as it was reactive with several functional, conformation-dependent monoclonal antibodies raised against P. falciparum malaria parasites, it induced antibodies (Abs) that were reactive to parasites in immunofluorescent Ab tests, and it induced strong growth and invasion inhibitory antisera in New Zealand White rabbits. The antigen quality was further evaluated by vaccinating Aotus nancymai monkeys and challenging them with homologous P. falciparum FVO erythrocytic-stage malaria parasites. The trial included two control groups, one vaccinated with the sexual-stage-specific antigen of Plasmodium vivax, Pvs25, as a negative control, and the other vaccinated with baculovirus-expressed MSP1(42) (FVO) as a positive control. Enzyme-linked immunosorbent assay (ELISA) Ab titers induced by E. coli MSP1(42) were significantly higher than those induced by the baculovirus-expressed antigen. None of the six monkeys that were vaccinated with the E. coli MSP1(42) antigen required treatment for uncontrolled parasitemia, but two required treatment for anemia. Protective immunity in these monkeys correlated with the ELISA Ab titer against the p19 fragment and the epidermal growth factor (EGF)-like domain 2 fragment of MSP1(42), but not the MSP1(42) protein itself or the EGF-like domain 1 fragment. Soluble MSP1(42) (FVO) expressed in E. coli offers excellent promise as a component of a vaccine against erythrocytic-stage falciparum malaria. 相似文献
28.
A rapid, cytopathic effect reduction assay for human interferon (IFN) is described. Dilutions of IFN were made with an automated diluter in 96-well microtiter plates. Total incubation time was 26 h. IFN titers were calculated from optical density readings of crystal violet-stained monolayers in an automated spectrophotometer, which required less than 1 min to read each plate. 相似文献
29.
Repeat sequences in block 2 of Plasmodium falciparum merozoite surface protein 1 are targets of antibodies associated with protection from malaria
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Polley SD Tetteh KK Cavanagh DR Pearce RJ Lloyd JM Bojang KA Okenu DM Greenwood BM McBride JS Conway DJ 《Infection and immunity》2003,71(4):1833-1842
Human antibodies to the block 2 region of Plasmodium falciparum merozoite surface protein 1 (MSP1) are associated with a reduced prospective risk of clinical malaria. Block 2 is highly polymorphic, but all known alleles can be grouped into three major types. Two of these types (the K1-like and MAD20-like types) contain type-specific sequences (found in all alleles of a particular type) that flank polymorphic tripeptide repeats. These repeats contain both type-specific and subtype-specific sequences. To evaluate the antibody recognition of these parts of block 2, a new panel of six recombinant proteins was used (fused type-specific flanking sequences and two representative repeat sequences for each of the K1-like and MAD20-like types separately). Extensive testing of these antigens and full-length block 2 antigens showed that human serum immunoglobulin G antibodies induced by infection can recognize (i) type-specific epitopes in the repeats, (ii) subtype-specific epitopes in the repeats, or (iii) type-specific epitopes in flanking sequences. A large prospective study in The Gambia showed that antibodies to the repeats are strongly associated with protection from clinical malaria. The results are important for design of a vaccine to induce protective antibodies, and they address hypotheses about repeat sequences in malaria antigens. 相似文献