全文获取类型
收费全文 | 3880篇 |
免费 | 158篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 180篇 |
妇产科学 | 51篇 |
基础医学 | 479篇 |
口腔科学 | 80篇 |
临床医学 | 271篇 |
内科学 | 686篇 |
皮肤病学 | 80篇 |
神经病学 | 272篇 |
特种医学 | 120篇 |
外科学 | 496篇 |
综合类 | 192篇 |
一般理论 | 1篇 |
预防医学 | 232篇 |
眼科学 | 202篇 |
药学 | 424篇 |
中国医学 | 24篇 |
肿瘤学 | 248篇 |
出版年
2023年 | 29篇 |
2022年 | 68篇 |
2021年 | 138篇 |
2020年 | 73篇 |
2019年 | 74篇 |
2018年 | 107篇 |
2017年 | 67篇 |
2016年 | 99篇 |
2015年 | 111篇 |
2014年 | 131篇 |
2013年 | 176篇 |
2012年 | 269篇 |
2011年 | 268篇 |
2010年 | 150篇 |
2009年 | 134篇 |
2008年 | 205篇 |
2007年 | 220篇 |
2006年 | 198篇 |
2005年 | 160篇 |
2004年 | 149篇 |
2003年 | 135篇 |
2002年 | 149篇 |
2001年 | 121篇 |
2000年 | 109篇 |
1999年 | 81篇 |
1998年 | 39篇 |
1997年 | 31篇 |
1996年 | 45篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 32篇 |
1991年 | 32篇 |
1990年 | 39篇 |
1989年 | 47篇 |
1988年 | 41篇 |
1987年 | 36篇 |
1986年 | 29篇 |
1985年 | 30篇 |
1984年 | 27篇 |
1983年 | 22篇 |
1982年 | 15篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 26篇 |
1978年 | 7篇 |
1977年 | 13篇 |
1974年 | 9篇 |
1971年 | 7篇 |
1970年 | 9篇 |
排序方式: 共有4051条查询结果,搜索用时 15 毫秒
81.
Nilay Kumar Ambarish Pandey Neetika Garg Emmanuel Sampene Carl J. Lavie 《Mayo Clinic proceedings. Mayo Clinic》2018,93(9):1185-1190
Objective
To ascertain whether temporal and geographic interest in seeking cardiovascular disease (CVD) information online follows seasonal and geographic patterns similar to those observed in real-world data.Methods
We searched Google Trends for popular search terms relating to CVD. Relative search volumes (RSVs) were obtained for the period January 4, 2004, to April 19, 2014, for the United States and Australia. We compared average RSVs by month and season and used cosinor analysis to test for seasonal variation in RSVs. We also assessed correlations between state-level RSVs and CVD burden using an ecological correlational design.Results
RSVs were 15% higher in the United States and 45% higher in Australia for winter compared with summer (P<.001 for difference for both). In the United States, RSVs were 36% higher in February compared with August, while in Australia, RSVs were 75% higher in August compared with January. On cosinor analysis, we found a significant seasonal variability in RSVs, with winter peaks and summer troughs for both the United States and Australia (P<.001 for zero amplitude test for both). We found a significant correlation between state-level RSVs and mortality from CVD (r=0.62; P<.001), heart disease (r=0.58; P<.001), coronary heart disease (r=0.48; P<.001), heart failure (r=0.51; P<.001), and stroke (r=0.60; P<.001).Conclusion
Google search query volumes related to CVD follow strong seasonal patterns with winter peaks and summer troughs. There is moderate to strong positive correlation between state-level search query volumes and burden of CVD mortality. 相似文献82.
B.?N.?Shashikumar P.?K.?Pandey Kundan?Kumar Saurav?KumarEmail author 《Proceedings of the National Academy of Sciences, India. Section B.》2018,88(2):553-557
The study was conducted to evaluate the effect of higher temperature beyond optimum range on acute toxicity for malathion (effective concentration 50 %) in Pangasianodon hypophthalmus. A 2 days renewal bioassay system for 96 h was used to determine LC50 value of malathion at three different regimes of temperature that is 30, 32 and 34 °C considering as T1, T2 and T3, respectively. The physico-chemical parameters of water of different treatment groups were estimated during pre and post-exposure of test chemical, following standard methods. The result of short term acute toxicity test at 96 h LC50 values through probit analysis was found to be 7.76, 6.45 and 4.46 µL L?1 for T1, T2, and T3, respectively. The 96 h LC50 of malathion at 34 °C was found to be significantly (p < 0.01) lower as compared with estimated LC50 for malathion at 30 and 32 °C. High temperature and free carbon dioxide coupled with low dissolved oxygen were significantly noticed in T3 group when compared to T1 and T2 groups. Lower LC50 of malathion at 34 °C as compared to 30 and 32 °C showed that at a higher temperature, the toxicity of malathion increased, signifying diminished fish protective response to malathion toxicity. The current study reflects the impact of increased temperature on pesticide toxicity in the aquatic ecosystem, alarming the aqua farmers to judiciously use malathion in ponds. 相似文献
83.
Gupta Rupali Singh Akanksha Kanaujia Ranjana Kushwaha Shaivya Pandey Rakesh 《Proceedings of the National Academy of Sciences, India. Section B.》2018,88(1):219-227
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Ocimum, an important commercial aromatic crop, is well known for the industrially acclaimed essential oil. In... 相似文献
84.
Ashok Kumar Reddy Raja Rami Reddy Muralidhar Rao Paruvelli Srinivas Ambatipudi Alka Rani Sikander A. K. Lodhi Juturi Maruthi Lokabhi Reddy K. Ramakanth Reddy Niraj Pandey Rituraj Videkar Manish Kumar Sinha Ajit Babu Majji Nilanjana Deb-Jorder Atul Kumar Sahu Jyostna Myneni Anina Abraham 《International ophthalmology》2015,35(1):37-42
85.
86.
87.
Khagesh Tanwar Deepankar Sri Gyan Prashant Gupta Shukdev Pandey OmParkash Devendra Kumar 《RSC advances》2018,8(35):19600
Ce4+ and Zn2+ co-doped barium hexaferrites (BFO) have been synthesized via a citrate-nitrate autocombustion route. Phase purity has been confirmed by high resolution (HR) powder X-ray diffraction analysis. Rietveld refinement on HR-XRD data has been carried out to reveal the crystal structure, bond angles and bond lengths. High-resolution scanning electron microscope (HR-SEM) has been used to study the effect of Ce4+ and Zn2+ on microstructure. Magnetic behavior of co-doped barium hexaferrites in the low temperature regime, 2–300 K has been studied. Further, it has been explained on the basis of superexchange interactions and formation of Bloch walls due to the presence of imperfections in the doped samples. It has been found that BFO changes hard to soft magnetic behavior when the temperature is decreased from 300 K to 2 K. Moreover, doping of Ce4+ and Zn2+ at Fe3+ site also brings similar effects which strengthens with decreasing temperature.Preparation of Ce–Zn substituted barium hexaferrites and investigation of their magnetic behavior in low temperature regime (2–300 K). 相似文献
88.
Risha Ganguly Ashutosh Gupta Abhay K Pandey 《World journal of gastroenterology : WJG》2022,28(26):3047-3062
Baicalin is a natural bioactive compound derived from Scutellaria baicalensis, which is extensively used in traditional Chinese medicine. A literature survey demonstrated the broad spectrum of health benefits of baicalin such as antio xidant, anticancer, anti-inflammatory, antimicrobial, cardio-protective, hepatoprotective, renal protective, and neuroprotective properties. Baicalin is hydrolyzed to its metabolite baicalein by the action of gut microbiota, which is further recon verted to baicalin via phase 2 metabolism in the liver. Many studies have suggested that baicalin exhibits therapeutic potential against several types of hepatic disorders including hepatic fibrosis, xenobiotic-induced liver injury, fatty liver disease, viral hepatitis, cholestasis, ulcerative colitis, hepatocellular and colorectal cancer. During in vitro and in vivo examinations, it has been observed that baicalin showed a protective role against liver and gut-associated abno rmalities by modifying several signaling pathways such as nuclear factor-kappa B, transforming growth factor beta 1/SMAD3, sirtuin 1, p38/mitogen-activated protein kinase/Janus kinase, and calcium/calmodulin-dependent protein kinase kinaseβ/adenosine monophosphate-activated protein kinase/acetyl-coenzyme A carboxylase pathways. Furthermore, baicalin also regulates the expression of fibrotic genes such as smooth muscle actin, connective tissue growth factor, β-catenin, and inflammatory cytokines such as interferon gamma, interleukin-6 (IL-6), tumor necrosis factor-alpha, and IL-1β, and attenuates the production of apoptotic proteins such as caspase-3, caspase-9 and B-cell lymphoma 2. However, due to its low solubility and poor bioavailability, widespread therapeutic applications of baicalin still remain a challenge. This review summarized the hepatic and gastrointestinal protective attributes of baicalin with an emphasis on the molecular mechanisms that regulate the interaction of baicalin with the gut microbiota. 相似文献
89.
Sinha PK Bimal S Pandey K Singh SK Ranjan A Kumar N Lal CS Barman SB Verma RB Jeyakumar A Das P Bhattacharya M Sur D Bhattacharya SK 《Annals of tropical medicine and parasitology》2008,102(2):119-125
In the Indian state of Bihar, the sensitivities and specificities of direct agglutination tests (DAT) and rK39 test strips for the detection of Leishmania donovani infection in humans were explored and found to be generally good (92%-100%). When 172 asymptomatic individuals [16 'case-contacts' who lived in the same households as past or current, confirmed cases of visceral leishmaniasis (VL) and 156 other subjects from neighbouring households] were tested, the same 36 (21%) individuals, including all 16 'case-contacts', were found seropositive using each type of test. When followed-up after 3 months, 18 of the individuals who had been found seropositive in the baseline survey remained seropositive, and eight (44%) of these had developed symptomatic VL, with amastigotes in their splenic aspirates. Seven (44%) of the 16 'case-contacts' but only one (5%) of the other 20 subjects found seropositive at baseline went on to develop VL within 3 months. Although the strip test appeared slightly better than DAT for predicting the development of VL in the 172 subjects, either type of test may be very useful for the early detection of asymptomatic L. donovani infection and thus the identification of those at relatively high risk of developing VL. 相似文献
90.
C. S. Lal R. B. Verma N. Verma N. A. Siddiqui V. N. Rabidas K. Pandey D. Singh S. Kumar R. K. Paswan A. Kumari P. Sinha P. Das 《Infection》2016,44(1):39-45