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   168449篇
  免费   15664篇
  国内免费   7781篇
耳鼻咽喉   2305篇
儿科学   3888篇
妇产科学   1820篇
基础医学   31025篇
口腔科学   5380篇
临床医学   12910篇
内科学   22977篇
皮肤病学   4691篇
神经病学   9475篇
特种医学   3701篇
外国民族医学   118篇
外科学   14690篇
综合类   25725篇
现状与发展   48篇
预防医学   4522篇
眼科学   3523篇
药学   12815篇
  29篇
中国医学   5036篇
肿瘤学   27216篇
  2024年   337篇
  2023年   2411篇
  2022年   4260篇
  2021年   6000篇
  2020年   5351篇
  2019年   5212篇
  2018年   5402篇
  2017年   5708篇
  2016年   5993篇
  2015年   6840篇
  2014年   9866篇
  2013年   10940篇
  2012年   9448篇
  2011年   10634篇
  2010年   8809篇
  2009年   8453篇
  2008年   8909篇
  2007年   9139篇
  2006年   8299篇
  2005年   7639篇
  2004年   6787篇
  2003年   5872篇
  2002年   4812篇
  2001年   4150篇
  2000年   3426篇
  1999年   3114篇
  1998年   2934篇
  1997年   2679篇
  1996年   2410篇
  1995年   2111篇
  1994年   1874篇
  1993年   1560篇
  1992年   1255篇
  1991年   1195篇
  1990年   917篇
  1989年   873篇
  1988年   820篇
  1987年   650篇
  1986年   604篇
  1985年   798篇
  1984年   707篇
  1983年   497篇
  1982年   520篇
  1981年   415篇
  1980年   356篇
  1979年   264篇
  1978年   184篇
  1977年   145篇
  1976年   110篇
  1973年   42篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.

Background

Partial nephrectomy (PN) is generally favored for cT1 tumors over radical nephrectomy (RN) when technically feasible. However, it can be unclear whether the additional risks of PN are worth the magnitude of renal function benefit.

Objective

To develop preoperative tools to predict long-term estimated glomerular filtration rate (eGFR) beyond 30 d following PN and RN, separately.

Design, setting, and participants

In this retrospective cohort study, patients who underwent RN or PN for a single nonmetastatic renal tumor between 1997 and 2014 at our institution were identified. Exclusion criteria were venous tumor thrombus and preoperative eGFR <15 ml/min/1.73 m2.

Intervention

RN and PN.

Outcome measurements and statistical analysis

Hierarchical generalized linear mixed-effect models with backward selection of candidate preoperative features were used to predict long-term eGFR following RN and PN, separately. Predictive ability was summarized using marginal RGLMM2, which ranges from 0 to 1, with higher values indicating increased predictive ability.

Results and limitations

The analysis included 1152 patients (13 206 eGFR observations) who underwent RN and 1920 patients (18 652 eGFR observations) who underwent PN, with mean preoperative eGFRs of 66 ml/min/1.73 m2 (standard deviation [SD] = 18) and 72 ml/min/1.73 m2 (SD = 20), respectively. The model to predict eGFR after RN included age, diabetes, preoperative eGFR, preoperative proteinuria, tumor size, time from surgery, and an interaction between time from surgery and age (marginal RGLMM2=0.41). The model to predict eGFR after PN included age, presence of a solitary kidney, diabetes, hypertension, preoperative eGFR, preoperative proteinuria, surgical approach, time from surgery, and interaction terms between time from surgery and age, diabetes, preoperative eGFR, and preoperative proteinuria (marginal RGLMM2). Limitations include the lack of data on renal tumor complexity and the single-center design; generalizability needs to be confirmed in external cohorts.

Conclusions

We developed preoperative tools to predict renal function outcomes following RN and PN. Pending validation, these tools should be helpful for patient counseling and clinical decision-making.

Patient summary

We developed models to predict kidney function outcomes after partial and radical nephrectomy based on preoperative features. This should help clinicians during patient counseling and decision-making in the management of kidney tumors.  相似文献   
93.
94.

Background

Clear cell renal cell carcinoma (ccRCC) is known to occur across the adult lifetime traversing the spectrum of age-related organismal changes. Little is known as to how the aging process may affect the course of renal cell carcinoma (RCC) and the repertoire of genes involved.

Methods

Using The Cancer Genome Atlas (n?=?436) and Cancer Genomics of the Kidney (n?=?89) datasets, we applied regression analysis to examine associations between patient age and gene expression profiles in ccRCC tumors and normal kidney tissues. Pathway enrichment analysis was performed to identify cellular process that is affected by aging in ccRCC. Moreover, connectivity mapping analysis was used to predict age-dependent response to drug treatments.

Results

Our analysis revealed different age-dependent gene expression spectra in ccRCC and normal kidney tissues. These findings were significant and independently reproducible in both datasets examined. Age up-regulated genes, showing higher expression in older patients, were significantly enriched (false discovery rate <0.05) in normal tissues for pathways associated with immune response and extracellular matrix organization, whereas age up-regulated genes in tumors were enriched for metabolism and oxidation pathways. Strikingly, age down-regulated genes in normal cells were also enriched for metabolism and oxidation, while those in tumors were enriched for extracellular matrix organization. Further in silico analysis of potential drug targets predicted preferential efficacy of Phosphoinositide 3-kinase inhibitor or immunotherapy in association with age.

Conclusion

We report on previously unrecognized associations between age and molecular underpinnings of RCC, including age-associated expression of genes implicated in RCC development or treatment.  相似文献   
95.
96.
Introduction: Nanoparticle albumin-bound paclitaxel (nab-paclitaxel), a microtubule inhibitor, has demonstrated clinical efficacy in the treatment of advanced non-small cell lung cancer (NSCLC) either as monotherapy or in combination. Nab-paclitaxel was developed to reduce the toxicities associated with solvent-bound paclitaxel (sb-paclitaxel).

Areas covered: This review first focuses on the clinical trials evaluating the efficacy and tolerability of nab-paclitaxel in NSCLC at different settings. The approval of nab-paclitaxel in combination with carboplatin at the front-line setting for advanced NSCLC was based on the key phase III study, which showed that nab-paclitaxel/carboplatin was associated with superior overall response rate and favorable toxicity profile compared to sb-paclitaxel/carboplatin. The review also addresses the nab-paclitaxel pharmacology, other combinations (e.g. immunotherapy with PD-1/PD-L1 inhibitors), potential biomarkers (e.g. caveolin-1), and special subgroups (e.g. the elderly, squamous histology).

Expert opinion: Existing data has established the role of nab-paclitaxel in the management of advanced NSCLC. Emerging evidence, such as preliminary results from Keynote-407 and IMpower 131 studies, indicates that novel combinations of nab-paclitaxel/carboplatin and PD-1/PD-L1 inhibitors could further improve clinical benefits with manageable toxicity. Nevertheless, in order to better position nab-paclitaxel and to improve patient selection, future studies are warranted to further understand its mechanism of action, predictive biomarkers, and potential synergism with other agents.  相似文献   

97.

Background

Acute myocardial infarction (AMI) causes irreversible myocardial damage and release of inflammatory mediators, including cytokines, chemokines and miRNAs. We aimed to investigate changes in the levels of cytokines (IL-6, TNF-α and IL-10), miRNAs profiles (miR-146 and miR-155) and distribution of different monocyte subsets (CD14++CD16-, CD14++CD16+, CD14+CD16++) in the acute and post-healing phases of AMI.

Methods

In eighteen consecutive AMI patients (mean age 56.78?±?12.4 years, mean left ventricle ejection fraction – LVEF: 41.9?±?9.8%), treated invasively, monocyte subsets frequencies were evaluated (flow cytometry), cytokine concentrations were analyzed (ELISA) as well as plasma miRNAs were isolated twice – on admission and after 19.2?±?5.9 weeks of follow-up. Measurements were also performed among healthy volunteers.

Results

AMI patients presented significantly decreased frequencies of classical cells in comparison to healthy controls (median 71.22% [IQR: 64.4–79.04] vs. 84.35% [IQR: 81.2–86.7], p?=?0.001) and higher percent of both intermediate and non-classical cells, yet without statistical significance (median 6.54% [IQR: 5.14–16.64] vs. 5.87% [IQR: 4.48–8.6], p?=?0.37 and median 5.99% [IQR: 3.39–11.5] vs. 5.26% [IQR: 3.62–6.2], p?=?0.42, respectively). In AMI patients both, analyzed plasma miRNA concentrations were higher than in healthy subjects (miR-146: median 5.48 [IQR: 2.4–11.27] vs. 1.84 [IQR: 0.87–2.53], p?=?0.003; miR-155: median 25.35 [IQR: 8.17–43.15] vs. 8.4 [IQR: 0.08–16.9], p?=?0.027, respectively), and returned back to the values found in the control group in follow-up. miR-155/miR-146 ratio correlated with the frequencies of classical monocytes (r=0.6, p?=?0.01) and miR-155 correlated positively with the concentration of inflammatory cytokines ? IL-6 and TNF-α.

Conclusions

These results may suggest cooperation of both pro-inflammatory and anti-inflammatory signals in AMI in order to promote appropriate healing of the infarcted myocardium.  相似文献   
98.
Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) has a high death rate in patients with comorbidities or in an immunocompromised state. We report a mild and attenuated SARS CoV-2 infection in a patient who is 17 months post stem cell transplantation and maintained on the JAK/STAT inhibitor ruxolitinib, a proposed novel therapy for SARS CoV-2 pneumonia.  相似文献   
99.
INTRODUCTIONThis study aimed to investigate the therapeutic response to injected human umbilical cord blood mesenchymal stem cells (UCBMSCs) among albino rats with streptozotocin (STZ)-induced diabetes mellitus.METHODSControl group (GI; n = 25) rats were fed with standard rat diet. Rats with STZ-induced diabetes mellitus without (GII; n = 25) and with (GIII; n = 25) differentiated human UCBMSCs implantation were the test groups. Rats were sacrificed in Week 11 following implantation. Liver biopsies were sectioned and stained in order to highlight both the presence and function of impregnated cells in the liver tissue.RESULTSHaematoxylin and eosin-stained sections in GI and GII rats showed normal liver architecture while GIII rats showed presence of cell clusters inside the liver tissue and around the central veins. Cell clusters with blue cytoplasm were present in sections in GIII rats but absent in GI and GII rats, indicating the presence of injected differentiated human UCBMSCs. The anti-human insulin immunostaining of GIII rats showed clusters of cells within the liver parenchyma and around central veins, indicating that these cells were active and secreting insulin.CONCLUSIONUCBMSCs are proficient in differentiating into insulin-producing cells in vivo under specific conditions and, when transplanted into the liver of albino rats with STZ-induced diabetes mellitus, were able to secrete insulin and partially control the status of diabetes mellitus in rats.  相似文献   
100.
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