全文获取类型
收费全文 | 78745篇 |
免费 | 4330篇 |
国内免费 | 92篇 |
专业分类
林业 | 3193篇 |
农学 | 2042篇 |
基础科学 | 461篇 |
8563篇 | |
综合类 | 15390篇 |
农作物 | 3121篇 |
水产渔业 | 3410篇 |
畜牧兽医 | 41695篇 |
园艺 | 854篇 |
植物保护 | 4438篇 |
出版年
2019年 | 721篇 |
2018年 | 1093篇 |
2017年 | 1215篇 |
2016年 | 1051篇 |
2015年 | 903篇 |
2014年 | 1196篇 |
2013年 | 2622篇 |
2012年 | 2120篇 |
2011年 | 2575篇 |
2010年 | 1617篇 |
2009年 | 1729篇 |
2008年 | 2596篇 |
2007年 | 2406篇 |
2006年 | 2286篇 |
2005年 | 2135篇 |
2004年 | 2076篇 |
2003年 | 2136篇 |
2002年 | 1921篇 |
2001年 | 2384篇 |
2000年 | 2440篇 |
1999年 | 1869篇 |
1998年 | 719篇 |
1997年 | 711篇 |
1996年 | 711篇 |
1995年 | 805篇 |
1993年 | 741篇 |
1992年 | 1553篇 |
1991年 | 1750篇 |
1990年 | 1634篇 |
1989年 | 1646篇 |
1988年 | 1472篇 |
1987年 | 1534篇 |
1986年 | 1596篇 |
1985年 | 1547篇 |
1984年 | 1184篇 |
1983年 | 1057篇 |
1982年 | 704篇 |
1979年 | 1152篇 |
1978年 | 894篇 |
1977年 | 755篇 |
1975年 | 774篇 |
1974年 | 1024篇 |
1973年 | 1024篇 |
1972年 | 1043篇 |
1971年 | 993篇 |
1970年 | 987篇 |
1969年 | 903篇 |
1968年 | 810篇 |
1967年 | 799篇 |
1966年 | 732篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
912.
913.
An improved vitrification protocol for equine immature oocytes,resulting in a first live foal 下载免费PDF全文
914.
915.
916.
917.
Clinical Evaluation of Tavocept to Decrease Diuresis Time and Volume in Dogs with Bladder Cancer Receiving Cisplatin 下载免费PDF全文
C.J. Henry B.K. Flesner S.A. Bechtel J.N. Bryan D.J. Tate K.A. Selting J.C. Lattimer M.E. Bryan L. Grubb F. Hausheer 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(1):370-376
Background
Transitional cell carcinoma is the most common bladder cancer of dogs. Cisplatin combined with piroxicam provides superior response rates, but unacceptable rates of nephrotoxicity. Tavocept is a chemoprotectant that has mitigated cisplatin toxicity and decreased the required infusion/diuresis volume in clinical trials in humans.Hypothesis/Objectives
We hypothesized that Tavocept would decrease diuresis volume and time and facilitate safe administration of a cisplatin/piroxicam protocol to dogs with bladder cancer. Secondary objectives were to compare response rate and survival times to an historical comparator group treated without Tavocept.Animals
Fourteen client‐owned dogs were prospectively enrolled.Methods
Tumor volume was measured by computed tomography at days 0, 42, and 84. Dogs received combination Tavocept/cisplatin with a shortened diuresis protocol. A total of 4 doses was planned, with concurrent administration of piroxicam. Serial biochemical analyses were evaluated for azotemia.Results
A 90‐minute infusion/diuresis time was used for all dogs. Three dogs (21%) had concurrent increases in serum creatinine (>2.0 mg/dL) and BUN (>42 mg/dL) concentrations; 2 of these dogs were isosthenuric. This frequency of nephrotoxicity is significantly less (P = 0.0406) than that of an historical control group treated without Tavocept. Overall response rate was 27%. Median survival time was comparable to historical controls (253 vs. 246 days).Conclusions and Clinical Importance
Tavocept decreased the required diuresis time with cisplatin from > 6 hours to 90 minutes, while also decreasing occurrence of azotemia. Survival time was comparable, but the response rate was inferior to an historical comparator group. Further evaluation in other tumors susceptible to platinum agents is warranted. 相似文献918.
Questionnaire‐based Analysis of Owner‐reported Scratching and Pain Signs in Cavalier King Charles Spaniels Screened for Chiari‐like Malformation and Syringomyelia 下载免费PDF全文
C.R. Sparks S. Cerda‐Gonzalez E.H. Griffith B.D.X. Lascelles N.J. Olby 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(1):331-339
Background
Chiari‐like malformation (CM) and syringomyelia (SM) cause a pain syndrome in Cavalier King Charles spaniels (CKCS). Clinical signs are not consistently apparent on neurologic examination, and owner reporting of signs provides vital clinical history. However, owner questionnaires for this disease are not well developed.Objectives
To develop a tool to capture owner‐reported clinical signs for use in clinical trials and to compare owner‐reported signs with the presence of pain on neurologic examination and SM on magnetic resonance imaging (MRI).Animals
Fifty client‐owned CKCS.Methods
Owners completed a questionnaire and pain/scratch map. Each dog underwent a neurologic examination and craniocervical magnetic resonance imaging (MRI). Questionnaire responses were developed into scores, area of shading for pain/scratch maps was measured, and consistency of responses between these tools was assessed. Owner‐reported findings were compared with neurologic examination findings and presence and severity of SM on MRI.Results
Thirty‐three dogs were symptomatic and 17 asymptomatic; 30 had SM. The most common sign of pain was crying out when lifted (n = 11). Extent of shaded areas on maps positively correlated with questionnaire scores for pain (r2 = 0.213, P = 0.006) and scratch (r2 = 0.104, P = 0.089). Owner‐reported findings were not significantly associated with presence or severity of SM or neurologic examination findings. Owner‐reported lateralization of signs was significantly associated with SM lateralization (P < 0.0001).Conclusions
The questionnaire and maps may be useful for clinical trials. Lack of association of owner‐reported signs with SM highlights our lack of understanding of the pathophysiology of pain in this disease. 相似文献919.
Canine GM2‐Gangliosidosis Sandhoff Disease Associated with a 3‐Base Pair Deletion in the HEXB Gene 下载免费PDF全文
P. Wang P.S. Henthorn E. Galban G. Lin T. Takedai M. Casal 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(1):340-347
Background
GM2‐gangliosidosis is a fatal neurodegenerative lysosomal storage disease (LSD) caused by deficiency of either β‐hexosaminidase A (Hex‐A) and β‐hexosaminidase B (Hex‐B) together, or the GM2 activator protein. Clinical signs can be variable and are not pathognomonic for the specific, causal deficiency.Objectives
To characterize the phenotype and genotype of GM2‐gangliosidosis disease in an affected dog.Animals
One affected Shiba Inu and a clinically healthy dog.Methods
Clinical and neurologic evaluation, brain magnetic resonance imaging (MRI), assays of lysosomal enzyme activities, and sequencing of all coding regions of HEXA, HEXB, and GM2A genes.Results
A 14‐month‐old, female Shiba Inu presented with clinical signs resembling GM2‐gangliosidosis in humans and GM1‐gangliosidosis in the Shiba Inu. Magnetic resonance imaging (MRI) of the dog's brain indicated neurodegenerative disease, and evaluation of cerebrospinal fluid (CSF) identified storage granules in leukocytes. Lysosomal enzyme assays of plasma and leukocytes showed deficiencies of Hex‐A and Hex‐B activities in both tissues. Genetic analysis identified a homozygous, 3‐base pair deletion in the HEXB gene (c.618‐620delCCT).Conclusions and Clinical Importance
Clinical, biochemical, and molecular features are characterized in a Shiba Inu with GM2‐gangliosidosis. The deletion of 3 adjacent base pairs in HEXB predicts the loss of a leucine residue at amino acid position 207 (p.Leu207del) supporting the hypothesis that GM2‐gangliosidosis seen in this dog is the Sandhoff type. Because GM1‐gangliosidosis also exists in this breed with almost identical clinical signs, genetic testing for both GM1‐ and GM2‐gangliosidosis should be considered to make a definitive diagnosis. 相似文献920.
Contrast‐Enhanced Ultrasound Examination for the Assessment of Renal Perfusion in Cats with Chronic Kidney Disease 下载免费PDF全文
E. Stock D. Paepe S. Daminet E. Vandermeulen L. Duchateau K. Vanderperren 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(1):260-266