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   99825篇
  免费   7118篇
  国内免费   321篇
耳鼻咽喉   1276篇
儿科学   2562篇
妇产科学   2308篇
基础医学   12465篇
口腔科学   2061篇
临床医学   9755篇
内科学   21797篇
皮肤病学   1065篇
神经病学   8661篇
特种医学   3362篇
外国民族医学   3篇
外科学   16244篇
综合类   1402篇
现状与发展   1篇
一般理论   75篇
预防医学   7924篇
眼科学   2650篇
药学   6353篇
中国医学   143篇
肿瘤学   7157篇
  2023年   402篇
  2022年   692篇
  2021年   1648篇
  2020年   880篇
  2019年   1588篇
  2018年   1905篇
  2017年   1400篇
  2016年   1556篇
  2015年   1836篇
  2014年   2728篇
  2013年   4323篇
  2012年   6190篇
  2011年   6462篇
  2010年   3618篇
  2009年   3343篇
  2008年   6126篇
  2007年   6823篇
  2006年   6516篇
  2005年   6666篇
  2004年   6500篇
  2003年   6122篇
  2002年   6114篇
  2001年   786篇
  2000年   549篇
  1999年   770篇
  1998年   1283篇
  1997年   1141篇
  1996年   967篇
  1995年   969篇
  1994年   846篇
  1993年   742篇
  1992年   567篇
  1991年   519篇
  1990年   456篇
  1989年   470篇
  1988年   438篇
  1987年   459篇
  1986年   447篇
  1985年   509篇
  1984年   709篇
  1983年   761篇
  1982年   980篇
  1981年   916篇
  1980年   867篇
  1979年   450篇
  1978年   531篇
  1977年   583篇
  1976年   492篇
  1975年   430篇
  1974年   341篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
BackgroundPortal vein embolization before liver resection is considered the therapy of choice for patients with inadequate future liver remnants. The concept of radioembolization with Yttrium-90 to achieve the same goal has limited data.MethodsWe retrospectively compared patients who underwent portal vein embolization and Yttrium-90 lobectomy before resection of hepatocellular carcinoma in patients with chronic liver disease.ResultsSeventy-three patients underwent portal vein embolization and 22 patients underwent Yttrium-90. Forty-seven percent of patients before portal vein embolization required additional procedures for tumor control, and 27% of patients after Yttrium-90 required additional procedure to mainly induce further hypertrophy. Both therapies achieved the goal of future liver remnants >40%, but the degree of hypertrophy was significantly higher in Yttrium-90 patients (63% for Yttrium-90, 36% for portal vein embolization, P < .01). Tumor response was significantly better with Yttrium-90, achieving complete response in 50% of patients. Resectability rate was higher after portal vein embolization (85% for portal vein embolization, 64% for Yttrium-90, P = .03). Tumor progression was the most common reason precluding surgery. Complete tumor control was the reason not to pursue surgery in 18% of patients after Yttrium-90.ConclusionBoth preoperative portal vein embolization and Yttrium-90, increases liver resectability rates by inducing hypertrophy of future liver remnants in patients with hepatocellular carcinoma and chronic liver disease. Yttrium-90 lobectomy achieved better tumor control and provided more time to assess therapy response, optimizing the indication for surgery.  相似文献   
992.
Most patients diagnosed with pancreatic cancer are classified as nonoperative candidates based on the contemporary guidelines of resectability. The advent of more potent control of systemic disease using neoadjuvant chemotherapy has enabled more aggressive operative interventions. In our multidisciplinary practice, patients with Stage III, locally advanced pancreatic cancer and superior mesenteric artery (SMA) encasement are now carefully triaged with high quality, preoperative imaging to determine if they can be considered candidates for operative resection with periadventitial dissection of the SMA. Patients displaying a “halo sign,” where the encased SMA remains fully patent and free from arterial invasion, are now candidates for SMA periadventitial dissection. This procedure involves the surgical stripping of the infiltrated neurolymphatic tissue off the SMA leaving behind a bare “skeletonized artery.” Alternatively, the “string sign” involving the SMA confers a more likely case of arterial invasion, where a complete oncologic resection cannot be achieved successfully. This method of patient selection in case of SMA involvement abandons the traditional metrics of circumferential degrees of the arterial encasement to guide surgical decisions. Our institutional approach has allowed us to meaningfully expand our operative methods of resection with the potential for improved longitudinal outcomes to pancreatic cancer patients who were deprived historically from the more effective and possibly curative treatment.  相似文献   
993.
BackgroundLiver transplantation is a complex surgical procedure. The experience of the anesthesiologist, and its potential relationship to patient morbidity and mortality, is yet to be determined. We sought to explore this possible association using our institutional training patterns as the subject of study.MethodsThis is a single center retrospective analysis investigating the association of an anesthesiologist's experience with liver transplantation and its potential effect on early patient outcomes in adult liver transplant recipients from January 2010 to September 2016. Training of team members consisted of a 6-month period of clinical shadowing with a senior anesthesiologist and co-staffing 8 liver transplant procedures before solo staffing a liver transplant. Specifically, patient outcomes for the first 5 transplants after this training were investigated.ResultsThe only independent risk factor for early death or early graft loss was the amount of packed red blood cells administered during transplantation. With respect to secondary outcomes, the amount of packed red blood cells and hospitalization at the time of transplant were associated with the number of days on a ventilator, length of intensive care unit stay, and overall hospital length of stay.ConclusionsThe results of this study conclude that the training model currently in place for our new team members has no negative impact on patient outcomes after liver transplantation.  相似文献   
994.
The role of mid-treatment monitoring dual-energy X-ray absorptiometry–bone mineral density (DXA-BMD) for bisphosphonate-treated patients with osteoporosis remains unsettled. A common reason for such monitoring is to encourage ongoing medication adherence. We sought to determine if a DXA-BMD treatment monitoring test was associated with improved medication adherence and whether improved adherence after a DXA-BMD treatment monitoring test was associated with subsequent reduction in fracture rates. Using linked administrative databases within Manitoba, Canada, we performed a retrospective cohort study of women starting and continuing antiresorptive therapy in whom a mid-treatment DXA-BMD monitoring test was performed. From the provincial pharmacy database, we estimated medication adherence by calculating annual medication possession ratio (MPR) and determining the change in MPR with respect to change (stable/decrease) in the DXA-BMD monitoring test, in addition to fracture rates before and after the test. The cohort comprised 3418 women, 90.7% treated with oral bisphosphonate, with pharmacy data for the 3 years before and after the mid-treatment DXA-BMD. Median (interquartile range) MPR was 0.84 (0.49–0.99) in the year before DXA-BMD and 0.84 (0.48–0.99) in the year after DXA-BMD (p = 0.37). Among those whose DXA-BMD declined, MPR in the prior year was 0.54 (0.04–0.92) but improved to 0.70 (0.31–0.92) in the year after DXA-BMD (p < 0.001). Among those whose DXA-BMD monitoring test was stable/improved, the fracture rate before the monitoring DXA-BMD was 10.1 per 1000 person-years and in those whose DXA-BMD monitoring test showed a decrease, the rate was 23.7 per 1000 person-years (p < 0.001). Despite improved adherence in those with DXA-BMD decline, the post DXA-BMD fracture rate was 22.4 per 1000 person-years versus 12.9 per 1000 person-years in those who had stable DXA-BMD (p < 0.001). A mid-treatment DXA-BMD reassessment strategy may be useful to focus attention upon adherence, but for optimal fracture outcomes, treatment adherence should be specifically addressed at the commencement of therapy. © 2021 American Society for Bone and Mineral Research (ASBMR).  相似文献   
995.
BackgroundSurvivors of childhood cancer may be at increased risk for treatment-related kidney dysfunction. Although associations with acute kidney toxicity are well described, evidence informing late kidney sequelae is less robust.MethodsTo define the prevalence of and risk factors for impaired kidney function among adult survivors of childhood cancer who had been diagnosed ≥10 years earlier, we evaluated kidney function (eGFR and proteinuria). We abstracted information from medical records about exposure to chemotherapeutic agents, surgery, and radiation treatment and evaluated the latter as the percentage of the total kidney volume treated with ≥5 Gy (V5), ≥10 Gy (V10), ≥15 Gy (V15), and ≥20 Gy (V20). We also used multivariable logistic regression models to assess demographic and clinical factors associated with impaired kidney function and Elastic Net to perform model selection for outcomes of kidney function.ResultsOf the 2753 survivors, 51.3% were men, and 82.5% were non-Hispanic White. Median age at diagnosis was 7.3 years (interquartile range [IQR], 3.3–13.2), and mean age was 31.4 years (IQR, 25.8–37.8) at evaluation. Time from diagnosis was 23.2 years (IQR, 17.6–29.7). Approximately 2.1% had stages 3–5 CKD. Older age at evaluation; grade ≥2 hypertension; increasing cumulative dose of ifosfamide, cisplatin, or carboplatin; treatment ever with a calcineurin inhibitor; and volume of kidney irradiated to ≥5 or ≥10 Gy increased the odds for stages 3–5 CKD. Nephrectomy was significantly associated with stages 3–5 CKD in models for V15 or V20.ConclusionsWe found that 2.1% of our cohort of childhood cancer survivors had stages 3–5 CKD. These data may inform screening guidelines and new protocol development.  相似文献   
996.
997.
998.
999.
The purpose of the present study was to analyze the difference in frontal plane rotation of the entire first ray in patients with and without hallux valgus using standing weightbearing computed tomography (CT). Ten feet of 10 patients with hallux valgus and 36 feet of 36 patients without hallux valgus were examined. Standing weightbearing CT scans and radiographs were taken for all subjects. Frontal plane measurements of the sesamoid apparatus, first metatarsal head, first metatarsal base, and medial cuneiform were performed. Frontal plane rotation of the first tarsometatarsal joint and intrinsic first metatarsal torsion was calculated. An independent 2 sample t test was used to compare means of outcomes of interest across control and treatment groups. Statistical significance was set at an alpha level of 0.05. There was a significant increase in pronation of the sesamoid apparatus (23.49° vs 6.60°) and first metatarsal head (17.79° vs 9.81°) in patients with hallux valgus. There was a significant increase in first metatarsal torsion toward pronation in patients with hallux valgus (22.28° vs 13.52°). No significant difference was detected in the rotation at the first tarsometatarsal joint or the frontal plane orientations of the first metatarsal base and medial cuneiform. By examining the frontal plane position of the entire first ray during weightbearing using standing CT in patients with and without hallux valgus, we determined the level at which pronation originates to be within the first metatarsal bone rather than the first tarsometatarsal joint.  相似文献   
1000.
Annals of Surgical Oncology - De-escalation of axillary surgery after neoadjuvant chemotherapy (NAC) requires careful patient selection. We seek to determine predictors of nodal pathologic complete...  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