首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   830篇
  免费   29篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   56篇
妇产科学   18篇
基础医学   91篇
口腔科学   23篇
临床医学   109篇
内科学   156篇
皮肤病学   9篇
神经病学   19篇
特种医学   167篇
外科学   40篇
综合类   5篇
一般理论   1篇
预防医学   30篇
眼科学   6篇
药学   94篇
肿瘤学   36篇
  2022年   6篇
  2021年   12篇
  2020年   4篇
  2018年   13篇
  2017年   5篇
  2016年   9篇
  2015年   12篇
  2014年   17篇
  2013年   31篇
  2012年   15篇
  2011年   31篇
  2010年   36篇
  2009年   27篇
  2008年   23篇
  2007年   21篇
  2006年   16篇
  2005年   22篇
  2004年   24篇
  2003年   17篇
  2002年   20篇
  2001年   17篇
  2000年   16篇
  1999年   12篇
  1998年   35篇
  1997年   29篇
  1996年   28篇
  1995年   26篇
  1994年   30篇
  1993年   20篇
  1992年   8篇
  1991年   12篇
  1990年   19篇
  1989年   21篇
  1988年   24篇
  1987年   18篇
  1986年   14篇
  1985年   21篇
  1984年   13篇
  1983年   12篇
  1982年   23篇
  1981年   15篇
  1980年   12篇
  1979年   8篇
  1978年   4篇
  1977年   9篇
  1976年   16篇
  1975年   9篇
  1968年   4篇
  1967年   3篇
  1965年   3篇
排序方式: 共有862条查询结果,搜索用时 12 毫秒
21.
Fludarabine was used to treat 68 patients with previously treated chronic lymphocytic leukemia (CLL). Nine (13%) patients achieved a complete remission and 30 (44%) a partial remission. The response rates for Rai stages 0 to 2, 3, and 4 were 64%, 58%, and 50% respectively. Seventeen (43%) of the 40 Rai stage 1 to 3 patients and four (19%) of the Rai stage 4 patients returned to Rai stage 0. Survival was strongly correlated with the final Rai stage achieved. The survival of the 11 partial responders with residual disease consisting only of residual bone-marrow nodules was similar to the complete responders (36+ months) and superior to the other partial response patients (16 months). The response to fludarabine was rapid, with 36 (92%) of the 39 responders having achieved at least a partial response following the first three courses. Complete responses occurred in the blood, liver, spleen, and lymph nodes in 48% to 69% of the patients. Eradication of all disease in the bone marrow occurred in only 13% of the cases. Neutropenia and thrombocytopenia occurred in 56% and 25% of evaluable courses. Major infections occurred in 9% of evaluable courses and fevers of unknown origin or minor infections in 12% of courses respectively. Myelosuppression and infection were more common in patients with initial Rai stages 3 and 4 and in nonresponding patients. Other toxicity was mild. No CNS toxicity was noted.  相似文献   
22.
23.
Potentially biodegradable graft polymer core‐shell nanoparticles assembling by addition of metal ions intended to be used for radionuclide and drug delivery purposes are described. With Cu2+ ions, the self‐assembly is slow (within minutes) with low efficiency. With Fe3+ ions the nanoparticles are formed immediately and are of convenient size for passive tumor accumulation by the enhanced permeation and retention effect. Full in vitro degradation of these particles is achieved with deferoxamine as a model of in vivo transchelation capacity.  相似文献   
24.
25.
IntroductionMen with erectile dysfunction (ED) are typically older and have one or more underlying cardiovascular conditions.AimTo determine the efficacy and safety of a new orodispersible tablet (ODT) formulation of vardenafil for the treatment of ED, and whether age, or the presence of underlying conditions affects treatment outcomes.MethodsThis is an integrated analysis of data from two phase III, double‐blind, multicenter, randomized, parallel‐group, placebo‐controlled studies that compared 10 mg on‐demand vardenafil ODT with placebo in a general population of men with ED, stratified so that approximately 50% of patients were aged ≥65 years. Results were reported by age (<65 vs. ≥65 years) and presence/absence of diabetes, dyslipidemia, or hypertension.Main Outcome MeasuresPrimary measures were the erectile function domain of the International Index of Erectile Function (IIEF‐EF) and Sexual Encounter Profile questions 2 (SEP2) and 3 (SEP3).ResultsOf the 701 men randomized (51% aged ≥65 years), 686 were included in the intent‐to‐treat population (placebo, n = 334; vardenafil ODT, n = 352). Vardenafil ODT was significantly superior to placebo for all primary efficacy measures, regardless of age, baseline ED severity, or underlying condition (P < 0.0001 for vardenafil vs. placebo for each endpoint). IIEF‐EF scores and SEP2/3 success rates in older patients and men with underlying conditions were not significantly different to those of younger patients or men without underlying conditions. Adverse events (AEs) were mostly mild to moderate in severity, occurring with higher incidence in the vardenafil vs. placebo group. The most frequently reported drug‐related AEs in the vardenafil group were headache, flushing, nasal congestion, dizziness, and dyspepsia, consistent with the known safety profile of phosphodiesterase type 5 inhibitors.ConclusionsVardenafil ODT significantly improves erectile function in men with ED regardless of age, baseline ED severity, or underlying condition. Sperling H, Gittelman M, Norenberg C, Ulbrich E, and Ewald S. Efficacy and safety of an orodispersible vardenafil formulation for the treatment of erectile dysfunction in elderly men and those with underlying conditions: An integrated analysis of two pivotal trials. J Sex Med 2011;8:261–271.  相似文献   
26.

Background

In November 2006, an email-based health promotion program for pregnant women was implemented nationally in the Netherlands. The program consisted of emails containing quizzes with pregnancy-related questions tailored to the number of weeks of pregnancy. Emails were sent out once every 4 weeks, up to a maximum of nine emails.

Objectives

The aims of the study were (1) to assess the recruitment of participants and their representativeness of the Dutch population and (2) to study differences in recruitment, program use, and program appreciation among women with different levels of education.

Methods

Data from 13,946 pregnant women who enrolled during the first year of the program were included. Upon registration, participants were asked how they found out about the program and subsequently received an email questionnaire to assess demographic, lifestyle, and Internet characteristics. Program use was tracked, and participants were classified into five user groups (inactive to very active). Program appreciation (low, intermediate, and high) was assessed twice with an email questionnaire that was sent after the woman had received her third and sixth quiz email. Information about pregnant women and their characteristics was obtained from Dutch registries to assess representativeness of the study population.

Results

About 8% of the pregnant women in the Netherlands enrolled in the program. Immigrants were underrepresented, and women with a low level of education seemed to be slightly underrepresented. Most women knew about the program from a promotional email sent by the organization (32%), followed by the Internet (22%) and midwives (16%). Women with little education were more often inactive users of the program than were highly educated women (15% vs 11%, P < .001), whereas highly educated women were more often very active users compared with women with little education (25% vs 20%, P< .001). However, women with less education were more likely than women with more education to have a high appreciation of the program after receiving three quiz emails (52% vs 44%, P = .001).

Conclusions

In this real-life setting, pregnant women can be reached through an email-based health promotion program. Selective engagement by education level remains a challenge.  相似文献   
27.
A novel system to study the effects of co-cross-linking CD23/FceRII and sIg on murine B lymphocytes utilizes a highly multivalent form of anti- Ig prepared by covalently linking anti-Ig antibodies to a DNP-dextran backbone. CD23-sIg co-cross-linking is accomplished by the addition of DNP-specific monoclonal IgE. Previous studies demonstrated that co- cross-linking CD23 and sIg significantly inhibited mouse B cell proliferation, especially at high doses of the multivalent anti-Ig. Interestingly, examination of early activation signals reveals no difference in B cells subjected to co-cross-linking conditions as compared to B cells activated with anti-Ig alone. Total cellular protein tyrosine phosphorylation levels are unchanged by co-cross- linking. Analysis of B cell mRNA reveals that co-cross-linking the receptors does not alter the expression levels of ornithine decarboxylase 8 h after stimulation as compared to the controls. In contrast, levels of the proto-oncogene c-myc were significantly elevated 1 h after inducing B cell activation under co-cross-linking conditions. However, it remains unclear whether this aberrant c-myc regulation plays any role in inducing apoptosis. In addition, on day 3 after stimulation, the co-cross-linking of CD23 and sIg resulted in the formation of apoptotic B cells, determined by both photomicroscopy of the B cell cultures and FACS analysis of B cell nuclei. B cells obtained from bcl-2 transgenic mice proliferated as well as controls, and failed to undergo apoptosis when CD23 and sIg were co-cross-linked on their surface. These studies indicate that co-cross-linking of CD23 with B cell sIg inhibits B cell proliferation by a mechanism that is distinct from that seen by co-cross-linking of the Fc gamma RII and sIg. In addition, these results suggest a means by which antigen- specific IgE can down-regulate additional B cell activation and IgE synthesis.   相似文献   
28.
Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused most often by mutations in the vasopressin V2 receptor (AVPR2). We studied a family which included a female patient with NDI with symptoms dating from infancy. The patient responded to large doses of desmopressin (dDAVP) which decreased urine volume from 10 to 4 I/day. Neither the parents nor the three sisters were polyuric. The patient was found to be a compound heterozygote for two novel recessive point mutations in the aquaporin-2 (AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is the site for inhibition of water permeation by mercurial compounds and is located near to the NPA motif conserved in all aquaporins. Osmotic water permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2 was not increased over water control, while expression of L22V cRNA increased the Pf to approximately 60% of that for wild-type AQP2. Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO cells showed that the C181W mutant had an endoplasmic reticulum-like intracellular distribution, whereas L22V and wild-type AQP2 showed endosome and plasma membrane staining. Water permeability assays showed a high Pf in cells expressing wild-type and L22V AQP2. This study indicates that AQP2 mutations can confer partially responsive NDI.   相似文献   
29.
We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.   相似文献   
30.
Corticosteroids are a mainstay of topical therapy for psoriasis. While efficacious and relatively safe when used carefully, the potential for side effects, notably skin atrophy and adrenal suppression, have been associated with excesses in potency, prolonged or widespread use. The International Psoriasis Council Working Group on Topical Therapy has reviewed the efficacy and safety of topical corticosteroids and recommends strategies for safe, long‐term use of these agents.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号