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   1339篇
  免费   111篇
  国内免费   14篇
耳鼻咽喉   2篇
儿科学   74篇
妇产科学   20篇
基础医学   165篇
口腔科学   32篇
临床医学   162篇
内科学   302篇
皮肤病学   4篇
神经病学   86篇
特种医学   182篇
外科学   208篇
综合类   44篇
预防医学   34篇
眼科学   14篇
药学   40篇
  1篇
肿瘤学   94篇
  2019年   9篇
  2018年   15篇
  2016年   10篇
  2015年   11篇
  2014年   21篇
  2013年   19篇
  2012年   29篇
  2011年   36篇
  2010年   23篇
  2009年   24篇
  2008年   41篇
  2007年   56篇
  2006年   49篇
  2005年   46篇
  2004年   52篇
  2003年   46篇
  2002年   37篇
  2001年   47篇
  2000年   42篇
  1999年   38篇
  1998年   34篇
  1997年   33篇
  1996年   33篇
  1995年   34篇
  1994年   32篇
  1993年   45篇
  1992年   37篇
  1991年   23篇
  1990年   31篇
  1989年   43篇
  1988年   39篇
  1987年   51篇
  1986年   39篇
  1985年   37篇
  1984年   19篇
  1983年   26篇
  1982年   21篇
  1981年   33篇
  1980年   19篇
  1979年   15篇
  1978年   18篇
  1977年   13篇
  1976年   9篇
  1975年   14篇
  1974年   13篇
  1973年   12篇
  1971年   8篇
  1970年   8篇
  1969年   8篇
  1968年   17篇
排序方式: 共有1464条查询结果,搜索用时 15 毫秒
101.
Two binding sites for l-[3H]glutamate were tentatively localized in rat fascia dentata by determining the effects of selective lesions on specific binding. Both destruction of dentate granule cells with colchicine and ablation of the ipsilateral entorhinal cortex markedly reduced radioligand binding to a quisqualate-sensitive site (GLU A), but only the entorhinal lesion significantly reduced binding to a site that is less sensitive to quisqualate (GLU B). These results suggest that GLU A binding sites are localized mainly on the dentate granule cells, whereas GLU B binding sites are localized, in part, on the perforant path fibers, but not on granule cells.  相似文献   
102.
1. In a study of the site of action of a steroid in current use for contraceptive purposes (6-chloro-Δ6-dehydro-17α-acetoxyprogesterone; `chlormadinone acetate'), the ovarian responses [secretion rate of 20α-hydroxypregn-4-en-3-one (20 α-OH), and the occurrence of ovulation] were observed in control oestrous rabbits and in rabbits following mating, injection of luteinizing hormone, and after electrical stimulation of the median eminence.  相似文献   
103.
PURPOSE: To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry portable system that utilizes a spark-gap electrode as an energy source. PATIENTS AND METHODS: We prospectively evaluated the first 312 treatments performed on 199 men and 99 women with an average age of 43.5 years (range 4 months-80 years), over a 25-month period between May 1999 and June 2001. Of the 468 stones treated, 136 were located in the ureter, 52 in the renal pelvis or ureteropelvic junction, and 230 in the kidney; the sites of 50 were not specified in our database. The average stone size was 8.0 mm (range 1-40 mm). Follow-up included a plain (KUB) film, CT scan, or intravenous urogram (IVU) and was available for 256 patients. "Stone free" was defined as no fragments visible on postoperative images. The mean radiographic follow-up was 74 days (range 0-866 days). Data collection was initially done manually by data sheets, but a Web-based medical database application was developed in order to enter, store, retrieve, and analyze the data more efficiently. RESULTS: The average number of shocks delivered per renal unit was 2689 at 25.8 kV. Seventy-five percent of the procedures were performed with intravenous sedation. Two thirds (169/256) of the patients were rendered stone free with one treatment. According to size, 71% (209/294) of stones <1 cm, 57% (39/68) of stones between 1.0 and 1.5 cm, and 22% (8/36) of stones >1.5 cm were eliminated. There were 23 patients who required further treatment; from the available data, 18 of them are currently stone free. Perioperative complications occurred in 6 patients (2%). No patient had worsening renal function or new-onset hypertension. The effectiveness quotient was 59.3%. CONCLUSION: The LithoTron lithotripter is satisfactory for stones <1 cm.  相似文献   
104.
105.
The marginal zone non-Hodgkin's lymphomas are a recently defined group of related low-grade B cell malignancies whose natural history is heterogeneous. The optimal therapy is often unclear, particularly for the subset of patients with disseminated disease that behaves aggressively. We have retrospectively analyzed the outcomes of 11 patients with chemosensitive but disseminated marginal zone lymphomas who underwent uniform conditioning with cyclophosphamide and total body irradiation followed by bone marrow transplantation (BMT) with anti-B cell monoclonal antibody-purged autologous bone marrow between January 1994 and September 1999. All patients had stage IV disease and received multiple chemotherapy regimens prior to autologous BMT. Only 36% were in complete remission at the time of bone marrow harvest, and 36% had overt bone marrow infiltration at that time. Two treatment-related deaths occurred between 100 days and 6 months. Three patients relapsed and died of disease. One patient developed and died of myelodysplasia. Five patients remain in continuous complete remission at a median follow-up of 52 months (45%). The median progression-free survival for these patients was 56 months, with median overall survival 58 months. The only significant predictor of disease-free and overall survival was age at the time of transplant; no patient under 45 at the time of transplant has relapsed or died of any cause (P = 0.003). Outcomes of autologous BMT in patients with disseminated marginal zone NHL are similar to those in follicular NHL, and suggest that certain patients may experience prolonged disease-free survival.  相似文献   
106.
Ethnic variations that may influence the preferences and outcomes associated with prostate cancer treatment are not well delineated. Our objective was to evaluate prospectively preferences, optimism, involvement in care, and quality of life (QOL) in black and white veterans newly diagnosed with localized prostate cancer. A total of 95 men who identified themselves as black/African-American or white who had newly diagnosed, localized prostate cancer completed a "time trade-off" task to assess utilities for current health and mild, moderate, and severe functional impairment; importance rankings for attributes associated with prostate cancer (eg, urinary function); and baseline and follow-up measures of optimism, involvement in care, and QOL. Interviews were scheduled before treatment, and at 3 and 12 months after treatment. At baseline, both blacks and whites ranked pain, bowel, and bladder function as their most important concerns. Optimism, involvement in care, and QOL were similar. Utilities for mild impairment were lower for blacks than whites, but were similar for moderate and severe problems. Decline in QOL at 3 and 12 months compared to baseline occurred for both groups. However, even with adjustment for marital status, education level, and treatment, blacks had less increase in nausea and vomiting and more increase in difficulty with sexual interest and weight gain compared with whites. Black and white veterans entered localized prostate cancer treatment with similar priorities, optimism, and involvement in care. Quality-of-life declines were common to both groups during the first year after diagnosis, but ethnic variation occurred with respect to nausea and vomiting, sexual interest, and weight gain.  相似文献   
107.
BACKGROUND: After markedly decreasing for 3 years, HIV/AIDS mortality declined only slightly in 1999. METHODS: The authors conducted a case-control study in four Florida urban public health HIV clinics to evaluate modifiable factors associated with HIV/AIDS mortality in a non-research setting. Structured chart review was conducted for 120 case-patients who died in 1999 and for 240 randomly selected control-patients. Risk factors associated with death in univariate analysis were entered into three conceptually related, matched logistic regression models. RESULTS: In the final multivariate model, homelessness (adjusted odds ratio [AOR], 9.98; 95% confidence interval [CI], 2.34-42.5), Medicaid insurance (AOR, 3.10; 95% CI, 1.43-6.74), having a documented adherence problem (AOR, 3.50; 95% CI, 1.64-7.47), injection drug use (AOR, 2.46; 95% CI, 1.11-5.43), non-specific liver failure (AOR, 76.9; 95% CI, 6.79-870.9), interrupted highly active antiretroviral therapy (HAART) secondary to side effects (AOR, 4.00; 95% CI, 1.46-10.9), and not receiving HAART (AOR, 2.62; 95% CI, 1.03-6.68) were independent predictors of mortality. CONCLUSIONS: In addition to medical and clinical indicators, several sociobehavioral-demographic factors remained important throughout the multivariate analysis. Improvement in care should include a focus on social circumstances of infected people. Special attention to the homeless, those with adherence problems, and those with liver disease is clearly indicated.  相似文献   
108.
109.
OBJECTIVE: Professional shampoos have previously been implicated in beauty parlor stroke syndrome and salon sink radiculopathy. The purpose of this study was to record pain, dizziness, and cervical blood flow while subjects were specifically placed into the salon sink position and to determine whether an additional cervical support would alter these symptoms and measurements. DESIGN: In 25 volunteers who reported previous dizziness from salon shampoos, we recorded subjective levels of pain and dizziness and objective measurements of blood flow within the vertebral and carotid arteries at baseline and then during cervical extension into a salon sink, with and without additional cervical support. RESULTS: When the additional cervical support was not used, there was significantly greater dizziness, neck pain, and carotid blood flow. No statistically significant differences were seen in the vertebral artery blood flow when comparing the three positions. CONCLUSIONS: Pain and dizziness were commonly reproduced in this previously symptomatic population but significantly less frequently when a supplemental cervical support was used. Individuals with a history of such symptoms should probably exercise caution when deciding whether to receive a salon sink shampoo.  相似文献   
110.
OBJECTIVE: To evaluate whether athletes with a history of low back pain (LBP) would, on average, perform slower on a timed 20-m shuttle run as compared with a normal athletic population. DESIGN: A timed shuttle run to evaluate residual functional limitations in college athletes with resolved LBP. SETTING: National College Athletic Association (NCAA) division I college. PARTICIPANTS: NCAA division I athletes (161 men, 50 women). INTERVENTION: A timed 20-m shuttle run. MAIN OUTCOME MEASURE: Each athlete was timed in a divided 20 m (66 ft) run in which 2 taped lines were positioned 6.7 m (22 ft) apart. RESULTS: Of 211 athletes evaluated, 27 had been treated for LBP during the previous year. Currently asymptomatic athletes with a recent history of LBP were slower (6.3s vs 5.8s) during performance of the timed 20-m shuttle run than athletes without LBP (P=.0002). CONCLUSIONS: Athletes with resolved LBP were slower than a matched group of normal athletes without LBP in the timed 20-m shuttle run. Further research is needed to support these findings and to understand fully the influence of the kinetic chain and the effects of both gender and sport on the observed findings.  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