全文获取类型
收费全文 | 8061篇 |
免费 | 431篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 206篇 |
妇产科学 | 647篇 |
基础医学 | 915篇 |
口腔科学 | 120篇 |
临床医学 | 902篇 |
内科学 | 1663篇 |
皮肤病学 | 79篇 |
神经病学 | 526篇 |
特种医学 | 240篇 |
外科学 | 1087篇 |
综合类 | 181篇 |
预防医学 | 408篇 |
眼科学 | 72篇 |
药学 | 586篇 |
中国医学 | 114篇 |
肿瘤学 | 768篇 |
出版年
2023年 | 39篇 |
2022年 | 99篇 |
2021年 | 176篇 |
2020年 | 93篇 |
2019年 | 146篇 |
2018年 | 248篇 |
2017年 | 168篇 |
2016年 | 157篇 |
2015年 | 210篇 |
2014年 | 244篇 |
2013年 | 385篇 |
2012年 | 586篇 |
2011年 | 592篇 |
2010年 | 383篇 |
2009年 | 323篇 |
2008年 | 501篇 |
2007年 | 549篇 |
2006年 | 547篇 |
2005年 | 445篇 |
2004年 | 386篇 |
2003年 | 319篇 |
2002年 | 316篇 |
2001年 | 262篇 |
2000年 | 272篇 |
1999年 | 201篇 |
1998年 | 54篇 |
1997年 | 55篇 |
1996年 | 57篇 |
1995年 | 31篇 |
1994年 | 44篇 |
1993年 | 25篇 |
1992年 | 128篇 |
1991年 | 92篇 |
1990年 | 68篇 |
1989年 | 42篇 |
1988年 | 46篇 |
1987年 | 44篇 |
1986年 | 44篇 |
1985年 | 27篇 |
1984年 | 34篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1979年 | 15篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1971年 | 10篇 |
排序方式: 共有8567条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVE To investigate the expression of Coxsackie and Adenovirus receptor (CAR) in renal-cell carcinoma and the relationship of the CAR to the biological behavior of the carcinomas.METHODS The immunohistochemical SP method was used to detect the expression of Coxsaekie and Adenovirus receptor in 48 cases of renalcell carcinoma and in 12 cases of normal renal tissue 2 cm away from the tumor tissue.RESULTS The positive rates of CAR were 100% in 12 cases of para-tumcr normal renal tissue and 35.4% in 48 cases of renal-cell carcinoma respectively. The difference of CAR expression between them was significant (P<0.05). The grades of the tumor were as follows: 22 in Grade Ⅰ, 17in Grade Ⅱ and 9 in Grade Ⅲ with the CAR positive rate being 54.5%,23.5% and 11.1%, respectively. There was a negative correlation between CAR expression and tumor grading (P<0.05). In addition, the number of the cases in stages Ⅰ to ⅣV were 19, 13, 11 and 5 respectively, with the respective positive rates being 57.9%, 30.8%, 18.2% and 0.0%, i.e. there also was a negative relationship between CAR expression and the stage (P<0.05).CONCLUSION CAR expression is down-regulated in renal-cell carcinoma compared with normal tissue. The level of CAR may be a sensitive predictor of differentiation, invasion and metastasis. Loss of CAR expression correlates with the invasive phenotype in our analysis of renal-cell carcinoma. 相似文献
93.
94.
Sulfath Hakkim Hazeena Chih-Yao Hou Jing-Huei Zeng Bo-Heng Li Tzu-Chih Lin Cai-Sian Liu Chi-I Chang Shu-Ling Hsieh Ming-Kuei Shih 《Materials》2022,15(22)
In fish processing, reducing the waste rate and increasing the economic value of products is an important issue for global environmental protection and resource sustainability. It has been discovered that cuttlefish bones can be an excellent resource for producing attractive amounts of chitin and chitosan. Therefore, this study optimized chitosan extraction conditions using response surface methodology (RSM) to establish application conditions suitable for industrial production and reducing environmental impact. In addition, Fourier-transform infrared spectroscopy (FTIR), 1H NMR and scanning electron microscope (SEM) characteristics of extracted chitosan were evaluated. The optimum extraction conditions for chitosan from cuttlebone chitin were 12.5M NaOH, 6 h and 80 °C, and the highest average yield was 56.47%. FTIR spectroscopy, 1H NMR, and SEM identification proved that the chitosan prepared from cuttlefish bone has a unique molecular structure, and the degree of deacetylation of chitosan was about 81.3%. In addition, it was also confirmed that chitosan has significant anti-oxidation and oil-absorbing abilities. This research has successfully transformed the by-products of cuttlefish processing into value-added products. The process not only achieved the recycling and utilization of by-products but also enhanced industrial competitiveness and resource sustainability. 相似文献
95.
Po-Yao Hsu Po-Cheng Liang Ching-I Huang Meng-Hsuan Hsieh Yi-Shan Tsai Tzu-Chun Lin Ming-Lun Yeh Chung-Feng Huang Chih-Wen Wang Tyng-Yuan Jang Yi-Hung Lin Zu-Yau Lin Wan-Long Chuang Chia-Yen Dai 《Viruses》2022,14(11)
The high accessibility to healthcare and increasing awareness of hepatocellular carcinoma (HCC) surveillance after sustained virologic response (SVR) to HCV treatment allow early detection of operable HCC in Taiwan. However, the effects of achieving SVR on patient characteristics and surgical outcomes after curative resection remain elusive. We aimed to compare the clinical presentation and postoperative prognosis among patients with early-stage HCV-related HCC and different viral status. We retrospectively analyzed 208 patients with BCLC stage 0 or A-HCC, including 44 patients who remained HCV viremic, 90 patients who developed HCC after achieving SVR (post-SVR HCC), and 74 patients who subsequently achieved SVR after resection. Patients with post-SVR HCC had a lower degree of hepatitis and better liver function than those who achieved SVR or remained viremic after resection. Notably, 75.6% of patients with post-SVR HCC did not have cirrhosis. Patients with post-SVR HCC and those achieving SVR after resection exhibited comparable recurrence rates and recurrence-free survival, while patients with persistent viremia had the worst surgical outcomes. We concluded that patients with post-SVR HCC had a better liver function but similar surgical outcomes compared with patients who achieved SVR after resection. The low prevalence of cirrhosis in patients with post-SVR HCC highlights the importance of regular surveillance after SVR. 相似文献
96.
Chi-Heng Kuo Te-I Chang Cheng-Hsien Chen Chun-You Chen Hui-Ling Hsieh Shih-Chang Hsu Ho-Shun Cheng Yuh-Mou Sue Tso-Hsiao Chen Yung-Ho Hsu Feng-Yen Lin Chun-Ming Shih Po-Hsun Huang Chung-Te Liu 《Medicine》2022,101(39)
While arteriovenous fistula (AVF) nonmaturation is a major issue of hemodialysis care, an effective treatment to improve AVF maturation remains lacking. AVF introduces pulsatile arterial blood flow into its venous limb and produces high luminal pressure gradient, which may have adverse effect on vascular remodeling. As such, the aim of the present study is to investigate effect of luminal pressure gradient on AVF nonmaturation. This single-center, prospective observational study includes patients receiving autologous AVF creation. Participants received early postoperative ultrasound 5–7 days after surgery to collect parameters including diameters, flow rates, and volume at inflow and outflow sites. Luminal pressure gradient was estimated by using modified Bernoulli equation. The outcome was spontaneous AVF maturation within 8 weeks after surgery without intervention. Thirty patients were included, of which the mean age was 66.9 years and 70% were male. At the end of study, 13 (43.3%) patients had spontaneous AVF maturation. All demographic and laboratory characteristics were similar between patients with mature and nonmature AVF. Regarding ultrasonographic parameters, nonmature AVF showed significantly higher inflow/outflow diameter ratio, inflow velocity, and luminal pressure gradient. While these 3 parameters were significantly correlated, multivariate logistic regression showed their significant association with AVF nonmaturation. Receiver operating characteristic curve exhibited their high predictive value for AVF nonmaturation. Our findings showed that higher inflow/outflow ratio, inflow velocity, and AVF luminal pressure gradient in early postoperative ultrasound predicted risk of AVF nonmaturation. Reducing inflow/outflow diameter ratio or inflow rate may be an approach to improve AVF maturation. The predictive value of this early assessment might have impact on the clinical practice of AVF care. 相似文献
97.
Dian-Jeng Li Hui-Ching Wu Frank Huang-Chih Chou Su-Ting Hsu Joh-Jong Huang Kuan-Ying Hsieh Guei-Ging Lin Pei-Jhen Wu 《Medicine》2022,101(42)
The coronavirus disease 2019 (COVID-19) pandemic has caused a heavily burden on healthcare workers (HCWs) worldwide. The aim of this study was to compare differences in psychological and social impact between two waves of the pandemic among first- and second-line HCWs in Taiwan. The current study derived data from two cross-sectional surveys conducted in 2020 and 2021. Levels of depression, sleep disturbance, psychological distress, social impact, and demographic variables were collected through self-reported questionnaires. The independent t test was used to compare differences in scores between the first and second wave of the pandemic. Differences between first- and second-line HCWs were also analyzed. A total of 711 HCWs in the first wave and 560 HCWs in the second wave were recruited. For the first- and second-line HCWs, the social impact during the second wave was higher than during the first wave, and they expressed a higher intention to maintain social distancing and were more aware of the pandemic overseas in the second wave. The first-line HCWs had a trend of worse sleep quality during the second wave. In addition, sleep quality was worse in the first-line HCWs than in the second-line HCWs during both waves. The second-line HCWs expressed a greater desire to seek COVID-19-related information than the first-line HCWs during the first wave, and more intended to maintain social distancing during the second wave. Our results show the importance of evaluating the social and mental health burden of HCWs, and especially first-line workers. 相似文献
98.
Hemangioblastomas are rare and benign tumors of the central nervous system. They account for 1.5%-2.5% of all intracranial tumors and have an incidence of 3.2%. The resemblance of hemangioblastomas to other tumors renders preoperative diagnosis and management challenging. Herein, we report a case of a supratentorial hemangioblastoma accompanied by extensive reactive gliosis and diagnosed through magnetic resonance imaging. In addition, we review the relevant literature. 相似文献
99.
Background: Nutrition and inflammation have been implicated in predicting mortality in patients on peritoneal dialysis (PD). Serum albumin and globulin can be regarded for the nutritional and inflammatory status. However, there is lack of data to evaluate the synergistic effect of albumin and globulin on mortality prediction. Methods: In 554 patients initiating PD from January 2001 to July 2016, we divided them into four groups by the combination of two categories of low vs. high albumin and low vs. high globulin. The median values for albumin and globulin were chosen to classify them into low or high groups. Their associations with all-cause and cardiovascular (CV) mortality were examined in Cox regression models adjusted for confounding clinical and laboratory data. Results: Patients, 52.91 ± 15.2 years old and 47.8% men, had a median (interquartile range) value of 3.3 (2.9–3.8) g/dL for albumin and 2.8 (2.5–3.2) g/dL for globulin, respectively. Patients with low albumin and high globulin had the highest all-cause mortality and CV mortality, with adjusted hazard ratios of 3.87 (95% CI 1.83–8.20, p < 0.001) and 5.65 (95% CI 2.23–14.34, p < 0.001), respectively, compared with those with a high albumin and low globulin having the lowest mortality rate. Sensitivity analyses further confirmed this relationship. Conclusions: A patient profile of either low albumin or high globulin is linked to a higher risk for mortality, particularly for a profile of both low albumin and high globulin compared with one without either of them. Further studies are needed to explore the mechanisms underlying this phenomenon and how to improve clinical outcomes in those high-risk patients. 相似文献
100.
Chun‐Liang Tung Da‐Tong Ju Bharath Kumar Velmurugan Bo Ban Tran D. Dung Dennis J.‐Y. Hsieh Vijaya P. Viswanadha Cecilia H. Day Yueh‐Min Lin Chih‐Yang Huang 《Environmental toxicology》2019,34(12):1320-1328
Carthamus tinctorius L. (Compositae) is used in Chinese medicine to treat heart disease and inflammation. In our previous study, we found that C. tinctorius L. inhibited lipopolysaccharides (LPS)‐induced tumor necrosis factor‐alpha (TNF‐α) activation, JNK expression, and apoptosis in H9c2 cardiomyoblast cells. The present study was performed to investigate the protective effect of C. tinctorius extract (CTF) on LPS‐challenged H9c2 myocardioblast cell and to explore the possible underlying mechanism. Cell viability assay showed that LPS treatment decreased the cell viability of H9c2 cell, whereas CTF treatment reversed LPS cytotoxicity in a dose‐dependent manner, especially in the LPS + CTF 25 (μg/mL) group. LPS treatment‐induced apoptosis was determined by transferase‐mediated dUTP nick end labeling assay, and by Western blot. LPS‐induced apoptotic bodies were decreased following CTF treatment. Expression of TNF‐α, FAS‐L, FAS, FADD, caspase‐8, BID, and t‐BID was significantly increased in LPS‐treated H9c2 cells. In contrast, it was significantly suppressed by the administration of CTF extract. In addition, CTF treatment activates antiapoptotic proteins, Bcl‐2 and p‐Bad, and downregulates Bax, cytochrome‐c, caspase‐9, caspase‐3, and apoptosis‐inducing factor expression. Furthermore, CTF exerted cytoprotective effects by activating insulin‐like growth factor‐I (IGF‐I) signaling pathway leading to downregulation of the apoptotic proteins involved in FAS death receptor pathway. In addition, AG1024 and IGF‐I receptor (IGF‐IR) inhibitor and siRNA silencing reverses the effect of CTF implying that CTF functions through the IGF‐IR pathway to inhibit LPS‐induced H9c2 apoptosis. These results suggest that treatment with CTF extract prevented the LPS‐induced apoptotic response through IGF‐I pathway. 相似文献