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   6233篇
  免费   379篇
  国内免费   94篇
耳鼻咽喉   52篇
儿科学   237篇
妇产科学   161篇
基础医学   756篇
口腔科学   92篇
临床医学   551篇
内科学   1391篇
皮肤病学   131篇
神经病学   465篇
特种医学   406篇
外科学   1149篇
综合类   65篇
一般理论   2篇
预防医学   447篇
眼科学   124篇
药学   348篇
  3篇
中国医学   29篇
肿瘤学   297篇
  2023年   42篇
  2022年   55篇
  2021年   154篇
  2020年   92篇
  2019年   143篇
  2018年   147篇
  2017年   127篇
  2016年   131篇
  2015年   133篇
  2014年   146篇
  2013年   205篇
  2012年   273篇
  2011年   315篇
  2010年   232篇
  2009年   205篇
  2008年   258篇
  2007年   339篇
  2006年   246篇
  2005年   264篇
  2004年   207篇
  2003年   230篇
  2002年   211篇
  2001年   176篇
  2000年   223篇
  1999年   172篇
  1998年   142篇
  1997年   132篇
  1996年   139篇
  1995年   123篇
  1994年   121篇
  1993年   93篇
  1992年   114篇
  1991年   112篇
  1990年   100篇
  1989年   94篇
  1988年   81篇
  1987年   78篇
  1986年   79篇
  1985年   74篇
  1984年   49篇
  1983年   49篇
  1982年   40篇
  1981年   42篇
  1980年   33篇
  1979年   21篇
  1977年   26篇
  1976年   23篇
  1975年   22篇
  1973年   31篇
  1971年   20篇
排序方式: 共有6706条查询结果,搜索用时 31 毫秒
81.
BACKGROUND: C-reactive protein (CRP), a marker of chronic subclinical inflammation (CSI), is related to cardiovascular mortality in the general and renal transplant populations. In the general population, high CRP levels are associated with pre-diabetic glucose homeostasis alterations which may contribute to the proatherogenic effect of CSI. METHODS: We studied 134 consecutive renal transplant recipients without pre-existing or new onset diabetes. CRP, oral glucose tolerance test, insulin sensitivity and HbA1c were measured. RESULTS: Among CRP tertiles, fasting glucose and glucose after 120 min were not different. However, HbA1c was higher (4.9+/-0.6; 5.2+/-0.5; 5.4+/-0.5; P=0.005] and insulin sensitivity lower (McAuley index: 7.2+/-2; 6.8+/-2; 6.2+/-1.3; P=0.042) in the third CRP tertile. In addition, HDL-cholesterol was lower and triglycerides and body mass index (BMI) higher in the third tertile. Consequently, metabolic syndrome was more prevalent in the upper CRP tertiles [11 (25%); 19 (43%); 22 (50%); P=0.01). In multivariate analyses, HbA1c was related to higher CRP levels (standardized beta coefficient=0.21, P=0.013), independently of BMI (standardized beta coefficient=0.24, P=0.005) and triglycerides (standardized beta coefficient=0.18; P=0.03). CONCLUSIONS: Subclinical glucose homeostasis alterations are related to chronic inflammation in renal transplant recipients without pre-existing or new onset diabetes and may contribute to their high cardiovascular mortality.  相似文献   
82.
ObjectiveParatesticular tumors are very rare and mostly bening. Wa aport a new case of adenomatoid tumor of epididymisMethodMale of 40 years old with solid lesion in epidididymis tale treated with mass exéresisResultsAdenoamotid tumor of the epididymis confirmed with hystopathologic techniqueConclusionAdenomatoid tumor of epididymis is the most frequent paratesticular tumors and when is suspected, conservative surgery must be performed  相似文献   
83.

Objective

Laparoscopic surgery is a successful treatment option offering significant advantages to patients compared with open ventral hernia repair. A cost-benefit analysis was performed to compare the clinical results and economic costs of the open and laparoscopic techniques for anterior abdominal wall hernia repair, in order to determine the more efficient procedure.

Material and methods

We performed a prospective study of 140 patients with primary and incisional hernia, and analyzed clinical data, morbidity, costs of surgery and hospital stay costs.

Results

The cost of disposable surgical supplies was higher with laparoscopic repair but reduced the average length of stay (P < .001) and patient morbidity (P < .001). The total cost of the laparoscopic procedure was, therefore, less than initially estimated, yielding a savings of 1,260 € per patient (2,865 € vs. 4,125 €).

Conclusions

Laparoscopic ventral hernia repair is associated with a reduced complication rate, a lower average length of stay and with lower total costs. Laparoscopic repair can save 1.260 € for each patient, and so this procedure should be considered a cost-effective approach.  相似文献   
84.
Transplant recipients receiving immunosuppressive therapy are at increased risk of active cytomegalovirus (CMV) infection and disease. Without appropriate prophylaxis, as many as 80% of solid organ transplant recipients may experience CMV infection. In addition to the direct effects of CMV, infection may be associated with a range of indirect effects, including an increase in risk of other infections, as well as a higher incidence of rejection, graft loss and death. The indirect effects of CMV infection can vary depending on the transplanted organ. For example, CMV-infected kidney transplant recipients may be at increased risk of cardiovascular disease and diabetes, while CMV infection in liver transplant recipients may potentiate hepatitis C infection and increase the risk of post-transplant lymphoproliferative disease. Indirect effects result from a number of pathological processes, including immune modulation and immunosuppression, generation of cytotoxic, pro-inflammatory responses, and smooth muscle proliferation. Prophylactic treatment with antiviral medication can reduce the risk of CMV disease, thereby improving graft survival and overall outcomes, particularly in kidney and heart transplant recipients. Antiviral prophylaxis should be considered for all patients at risk of CMV infection after solid organ transplantation. In this paper we review the main indirect effects of CMV infection in solid organ transplant recipients, and the impact of CMV prophylaxis on these effects.  相似文献   
85.
Animal‐assisted interventions (AAIs) have been found to decrease stress in some settings, but it is not known if AAI is feasible in an aeromedical staging facility or effective in reducing stress following aeromedical evacuation (AE) of military personnel. An experimental design was used to evaluate the efficacy of AAI at reducing stress in AE military patients (N = 120). Patients participated in a 20‐min AAI (n = 60) or 20‐min informational session about assistance dogs as an attention‐control group (n = 60). Demographics, post‐traumatic stress symptom severity (PTSSS), and stress biomarkers (cortisol, alpha‐amylase, and immunoglobulin A) were collected regular intervals. AAI was found feasible and efficacious at reducing stress. Cortisol decreased significantly (p < .05) in the AAI group compared with the attention‐control group. PTSSS moderated the immunoglobulin A responses to AAI as demonstrated by the interaction of PTSD Checklist–Military Version score, group, and time, F(1, 111.23) = 4.15 p = .044; effect size: d = 0.31. This research supports AAI as a stress‐reducing modality in AE patients, particularly those who report higher PTSSS. Implications for future research are discussed.  相似文献   
86.
87.
Morales P  Pasten C 《Andrologia》2004,36(3):101-105
In this work, we have compared two procedures that evaluate the acrosomal status of human sperm bound to the human zona pellucida. Motile sperm, selected by a Percoll gradient, were capacitated by incubation at 37 degrees C, 5% CO2, for 4.5 h, at 20 x 10(6) cells ml(-1). Then, the sperm were incubated with nonviable human oocytes for 10 min at 37 degrees C, 5% CO2. The oocytes with bound sperm were transferred to 500 microl phosphate-buffered saline (PBS) and washed to remove loosely bound sperm. The oocytes were then processed according to the procedures of Cross et al. (1986) or Liu & Baker (1996). In the Cross's procedure, the sperm were labelled while they were bound to the zona. In the Liu's procedure, the sperm were first dislodged from the zona into a droplet of PBS and labelled in there. Both procedures gave equivalent percentages of acrosome-reacted sperm. However, the total number of zona-bound sperm available for assessment with the procedure of Liu & Baker was greater than that of Cross et al. We suggest to use the former procedure to evaluate the acrosomal status of zona-bound sperm in humans. Moreover, this procedure also provided information about sperm ability to bind to the zona pellucida.  相似文献   
88.
Minactivin expression in human monocyte and macrophage populations   总被引:4,自引:0,他引:4  
Adherent monolayer cultures of human blood monocytes, peritoneal macrophages, bone marrow macrophages, and colonic mucosa macrophages were examined for their ability to produce and secrete minactivin, a specific inactivator of urokinase-type plasminogen activator. All except colonic mucosa macrophages produced and secreted appreciable amounts of minactivin, but only blood monocytes were stimulated by muramyl dipeptide (adjuvant peptide) to increase production. The minactivin from each of these populations could be shown to preferentially inhibit urokinase-type plasminogen activator and not trypsin, plasmin, or "tissue"-type plasminogen activator (HPA66). A plasminogen-activating enzyme present in monocyte cultures appeared unaffected by the presence of minactivin and could be shown to be regulated independently by dexamethasone.  相似文献   
89.
This multicenter, open, phase IIIb study assessed short-term efficacy, safety and dose adjustments in adult stable renal transplant recipients converted from tacrolimus twice-daily (BID) to once-daily (QD). Patients receiving unchanged tacrolimus BID for ≥ 12 weeks were enrolled, and after 6-weeks, converted from tacrolimus BID to QD (morning dose) on a 1 : 1 (mg : mg) total daily dose basis, for a further 12 weeks. Primary endpoint: change in steady-state creatinine clearance between treatment phases. Secondary endpoints: biopsy-proven acute rejection (BPAR), patient and graft survival, safety. 128 patients enrolled (mean age 48.9 years; time post-transplant 48.9 months); 91 evaluated for the primary endpoint. Mean total daily dose was 0.06 mg/kg (BID) and 0.07 mg/kg (QD); 79.1% required one/no dose changes post-conversion to maintain recommended blood-trough levels; average dose increase was small (0.6-0.7 mg/day) with more dose increases in patients on the lowest tacrolimus BID doses. Renal function remained stable and non-inferiority of tacrolimus QD against tacrolimus BID was demonstrated. There were no BPAR episodes; patient and graft survival were 100%. Adverse events were few; none led to dose modifications/discontinuation. Tacrolimus BID to tacrolimus QD conversion is straightforward and does not compromise renal function in stable kidney transplant patients in the short term.  相似文献   
90.
Arterial hypertension is highly prevalent after renal transplantation and may contribute to the risk of cardiovascular disease. Also, arterial hypertension has been reported to be an independent risk factor for graft failure. Immunosuppressive drugs such as corticosteroids, cyclosporine and tacrolimus may be important contributing factors to post-transplant hypertension. Recent data from multicenter trials and from conversion studies (cyclosporine to tacrolimus) suggest that renal transplant patients under tacrolimus-based therapy showed less arterial hypertension compared with cyclosporine treated patients. New immunosuppressive drugs, including mycophenolate mofetil and rapamycin, are not nephrotoxic and they do not have any hypertensive effect. New immunosuppressive combinations including mycophenolate mofetil in a triple therapy regimen (associated with corticosteroids and cyclosporine) can reduce blood pressure so that corticosteroids can be stopped or cyclosporine reduced or even eliminated. Non-nephrotoxic regimens using rapamycin (sirolimus) as basic immunosuppression, associated with azathioprine or mycophenolate mofetil, could reduce the incidence of post-transplant arterial hypertension. Also, in renal transplant patients initially immunosuppressed with rapamycin, cyclosporine and corticosteroids, after the elimination of CSA, a lower blood pressure is achieved. In summary, new protocols with mycophenolate mofetil and/or rapamycin may permit several combinations that offer important alternatives to classical immunosuppressive regimens to reduce the incidence and clinical impact of arterial hypertension after renal transplantation.  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