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   1538篇
  免费   66篇
  国内免费   57篇
耳鼻咽喉   1篇
儿科学   71篇
妇产科学   12篇
基础医学   155篇
口腔科学   21篇
临床医学   164篇
内科学   448篇
皮肤病学   52篇
神经病学   75篇
特种医学   300篇
外科学   66篇
综合类   33篇
预防医学   110篇
眼科学   15篇
药学   71篇
中国医学   2篇
肿瘤学   65篇
  2023年   4篇
  2022年   5篇
  2021年   12篇
  2020年   10篇
  2019年   10篇
  2018年   21篇
  2017年   4篇
  2016年   9篇
  2015年   19篇
  2014年   24篇
  2013年   55篇
  2012年   51篇
  2011年   33篇
  2010年   49篇
  2009年   79篇
  2008年   57篇
  2007年   108篇
  2006年   63篇
  2005年   44篇
  2004年   48篇
  2003年   27篇
  2002年   32篇
  2001年   26篇
  2000年   27篇
  1999年   42篇
  1998年   72篇
  1997年   82篇
  1996年   102篇
  1995年   63篇
  1994年   58篇
  1993年   54篇
  1992年   17篇
  1991年   17篇
  1990年   22篇
  1989年   40篇
  1988年   36篇
  1987年   34篇
  1986年   45篇
  1985年   41篇
  1984年   8篇
  1983年   14篇
  1982年   13篇
  1981年   10篇
  1980年   11篇
  1979年   10篇
  1978年   13篇
  1977年   9篇
  1976年   13篇
  1975年   13篇
  1973年   2篇
排序方式: 共有1661条查询结果,搜索用时 15 毫秒
41.
42.

Objective

To review the strengths and weaknesses of deliberative and intuitive processes in the context of patient decision support and to discuss implications for decision aid (DA) design.

Methods

Conceptual review of the strengths and weaknesses of intuitive and analytical decision making and applying these findings to the practice of DA design.

Results

DAs combine several important goals: providing information, helping to clarify treatment related values, supporting preference construction processes, and facilitating more active engagement in decision making. Many DAs encourage patients to approach a decision analytically, without solid theoretical or empirical grounding for this approach. Existing research in other domains suggests that both intuition and deliberation may support decision making. We discuss implications for patient decision support and challenge researchers to determine when combining these processes leads to better outcomes.

Conclusions

Intuitive and analytical decision processes may have complementary effects in achieving the desired outcomes of patient decision support.

Practice implications

DA developers should be aware that tools solely targeted at supporting deliberation may limit DA effectiveness and harm preference construction processes. Patients may be better served by combined strategies that draw on the strengths and minimize the weaknesses of both deliberative and intuitive processes.  相似文献   
43.

Background

Chronic kidney disease (CKD) is highly prevalent in patients with diabetes or hypertension in primary care. A shared care model could improve quality of care in these patients

Aim

To assess the effect of a shared care model in managing patients with CKD who also have diabetes or hypertension.

Design and setting

A cluster randomised controlled trial in nine general practices in The Netherlands.

Method

Five practices were allocated to the shared care model and four practices to usual care for 1 year. Primary outcome was the achievement of blood pressure targets (130/80 mmHg) and lowering of blood pressure in patients with diabetes mellitus or hypertension and an estimated glomerular filtration rate (eGFR)<60ml/min/1.73m2.

Results

Data of 90 intervention and 74 control patients could be analysed. Blood pressure in the intervention group decreased with 8.1 (95% CI = 4.8 to 11.3)/1.1 (95% CI = −1.0 to 3.2) compared to −0.2 (95% CI = −3.8 to 3.3)/−0.5 (95% CI = −2.9 to 1.8) in the control group. Use of lipid-lowering drugs, angiotensin-system inhibitors and vitamin D was higher in the intervention group than in the control group (73% versus 51%, 81% versus 64%, and 15% versus 1%, respectively, [P = 0.004, P = 0.01, and P = 0.002]).

Conclusion

A shared care model between GP, nurse practitioner and nephrologist is beneficial in reducing systolic blood pressure in patients with CKD in primary care.  相似文献   
44.

Background

Consensus guidelines have recommended that decision aids include a process for helping patients clarify their values. We sought to examine the theoretical and empirical evidence related to the use of values clarification methods in patient decision aids.

Methods

Building on the International Patient Decision Aid Standards (IPDAS) Collaboration’s 2005 review of values clarification methods in decision aids, we convened a multi-disciplinary expert group to examine key definitions, decision-making process theories, and empirical evidence about the effects of values clarification methods in decision aids. To summarize the current state of theory and evidence about the role of values clarification methods in decision aids, we undertook a process of evidence review and summary.

Results

Values clarification methods (VCMs) are best defined as methods to help patients think about the desirability of options or attributes of options within a specific decision context, in order to identify which option he/she prefers. Several decision making process theories were identified that can inform the design of values clarification methods, but no single “best” practice for how such methods should be constructed was determined. Our evidence review found that existing VCMs were used for a variety of different decisions, rarely referenced underlying theory for their design, but generally were well described in regard to their development process. Listing the pros and cons of a decision was the most common method used. The 13 trials that compared decision support with or without VCMs reached mixed results: some found that VCMs improved some decision-making processes, while others found no effect.

Conclusions

Values clarification methods may improve decision-making processes and potentially more distal outcomes. However, the small number of evaluations of VCMs and, where evaluations exist, the heterogeneity in outcome measures makes it difficult to determine their overall effectiveness or the specific characteristics that increase effectiveness.
  相似文献   
45.
Fletcher  MP; Gasson  JC 《Blood》1988,71(3):652-658
Human granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances numerous functions of mature neutrophils (PMN) including phagocytosis, superoxide responses to chemotaxins, antibody-dependent cellular cytotoxicity, and expression of complement receptors. A central question concerns whether the mechanism of enhancement involves quantitative increases in the response of all cells v subpopulation recruitment. The effects of GM-CSF on individual cell light scatter changes, membrane potential, and oxidant responses induced by the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (FMLP) were assessed by flow cytometry and by scoring individual cells for nitroblue tetrazolium dye (NBT) reduction. GM-CSF produced a dose- and time-dependent shift in forward light scatter that was very similar in character to that seen with FMLP or leukotriene B4 stimulation. Although not capable of depolarizing the cells directly, GM-CSF primed PMNs for enhanced membrane potential responses to FMLP by significantly increasing the proportion of depolarizing cells when compared with diluent-treated controls after a 60-minute incubation at 37 degrees C (79.4% +/- 3.4% v 29.5% +/- 4.7% GM-CSF v diluent, mean +/- SE, P less than .005, n = 11). Subpopulation recruitment by GM-CSF treatment was also demonstrated by the FMLP-elicited NBT test. Taken together, these results indicate that GM-CSF can modulate the function of mature PMN by enhancing the proportion of responsive cells.  相似文献   
46.
Young  JC; Bruno  E; Luens  KM; Wu  S; Backer  M; Murray  LJ 《Blood》1996,88(5):1619-1631
Thrombopoietin (TPO) or MpI ligand is known to stimulate megakaryocyte (MK) proliferation and differentiation. To identify the earliest human hematopoietic cells on which TPO acts, we cultured single CD34+Thy- 1+Lin- adult bone marrow cells in the presence of TPO alone, with TPO and interleukin-3 (IL-3), or with TPO and c-kit ligand (KL) in the presence of a murine stromal cell line (Sys1). Two distinct growth morphologies were observed: expansion of up to 200 blast cells with subsequent differentiation to large refractile CD41b+ MKs within 3 weeks or expansion to 200-10,000 blast cells, up to 25% of which expressed CD34. The latter blast cell expansions occurred over a 3- to 6-week period without obvious MK differentiation. Morphological staining, analysis of surface marker expression, and colony formation analysis revealed that these populations consisted predominantly of cells committed to the myelomonocytic lineage. The addition of IL-3 to TPO-containing cultures increased the extent of proliferation of single cells, whereas addition of KL increased the percentage of CD34+ cells among the expanding cell populations. Production of multiple colony- forming unit-MK from single CD34+Thy-1+Lin- cells in the presence of TPO was also demonstrated. In limiting dilution assays of CD34+Lin- cells, TPO was found to increase the size and frequency of cobblestone areas at 4 weeks in stromal cultures in the presence of leukemia inhibitory factor and IL-6. In stroma-free cultures, TPO activated a quiescent CD34+Lin-Rhodamine 123lo subset of primitive hematopoietic progenitor cells into cycle, without loss of CD34 expression. These data demonstrate that TPO acts directly on and supports division of cells more primitive than those committed to the MK lineage.  相似文献   
47.
48.
49.

Background and aims

The natural history of primary biliary cirrhosis (PBC) has so far mainly been studied in tertiary referral centres. The aim of the present investigation was to describe the natural history of PBC in a large population-based cohort in order to identify risk factors for development of malignancies and disease progression.

Methods

Four independent hospital databases were searched in 44 hospitals in a geographically defined area, after which all medical records were evaluated on site. In addition, PBC registries in the three liver transplant centers were checked for missed referrals from the area of interest.

Results

In total, 992 cases fulfilled the inclusion criteria. The median follow-up was 73 months (range 0–434). Mortality was similar to the age- and gender matched population (SMR 1.1; 95 % CI 0.9–1.4). Male gender, smoking, and elevated bilirubin, decreased albumin, and elevated AST at time of diagnosis, were associated with an increased risk for the combined end point PBC-related death or liver transplantation. In total, 133 (13 %) patients developed one or more malignancies (SIR 1.5; 95 % CI 1.1–1.9). There was a ninefold increased risk of developing hepatobiliary malignancies (SIR 9.4; 95 % CI 3.04–21.8), a fivefold increased risk of developing urinary bladder cancer (SIR 5.0; 95 % CI 1.6–11.6), and a 1.8-fold increased risk of developing breast cancer (SIR 1.8; 95 % CI 1.08–2.81).

Conclusion

PBC is associated with an increased risk of hepatobiliary, bladder and breast cancer. Still, survival—under treatment with ursodeoxycholic acid (UDCA)—was comparable to the general population in this population-based study.  相似文献   
50.
Objective:To investigate the wound healing properly of Napoleona vogelii leaf extract in folkloric medicine.Methods:Roth sexes of adult albino rats(n=25) were used in this study and another group(n=30) were subjected to acute toxicity test(LD_(50)) of the plant extract.For the LD_(50),three randomized groups of 5 rats were first treated with 10,100,1 000 mg/kg body weight(bw),orally.This w as followed by a second treatment of 1500,3000,and 5 000 mg/kg bw of the leaf extract with continual monitoring of the animals for mortality or non-mortality.Incision wounds(1.3cm) were created on the skin of five groups of 5 rals using surgical blade under anesthesia.The first group was topically treated with petroleum jelly alone,group 2 was topically applied 400 mg/mL w/v of the reference drug,Neobaein,while group 3-5 were topically treated with 5-50 mg/mL w/v of the plant extract,respectively.Results:The percentage yield of the extract was 49.80%w/w dry matter.The phytochemical analysis revealed several bioactive constituents including glycosides,tannins,alkaloids,perpenoids.saponins,steroids,proteins,and carbohydrates.The LD_(50) was beyond our experimental limit and was not determined.Increased concentrations(5,20,and 50mg/mL w/v) of the extract had significant(ANOVA,P0.05) healing effect on the incision wounds giving rise to 125%-140% while treatmentawith Neobacin resulted in 150% healing effect on the third treatment regimen compared to the control(100%).Conclusions:These data indicate that Napoleona vogelii leaf extract contains potent bioactive compounds containing wound healing activity,substantiating its use as a wound healer in folkloric medicine.  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